1: /*
2: ** 2001 September 15
3: **
4: ** The author disclaims copyright to this source code. In place of
5: ** a legal notice, here is a blessing:
6: **
7: ** May you do good and not evil.
8: ** May you find forgiveness for yourself and forgive others.
9: ** May you share freely, never taking more than you give.
10: **
11: *************************************************************************
12: ** This header file defines the interface that the SQLite library
13: ** presents to client programs. If a C-function, structure, datatype,
14: ** or constant definition does not appear in this file, then it is
15: ** not a published API of SQLite, is subject to change without
16: ** notice, and should not be referenced by programs that use SQLite.
17: **
18: ** Some of the definitions that are in this file are marked as
19: ** "experimental". Experimental interfaces are normally new
20: ** features recently added to SQLite. We do not anticipate changes
21: ** to experimental interfaces but reserve the right to make minor changes
22: ** if experience from use "in the wild" suggest such changes are prudent.
23: **
24: ** The official C-language API documentation for SQLite is derived
25: ** from comments in this file. This file is the authoritative source
26: ** on how SQLite interfaces are supposed to operate.
27: **
28: ** The name of this file under configuration management is "sqlite.h.in".
29: ** The makefile makes some minor changes to this file (such as inserting
30: ** the version number) and changes its name to "sqlite3.h" as
31: ** part of the build process.
32: */
33: #ifndef SQLITE3_H
34: #define SQLITE3_H
35: #include <stdarg.h> /* Needed for the definition of va_list */
36:
37: /*
38: ** Make sure we can call this stuff from C++.
39: */
40: #ifdef __cplusplus
41: extern "C" {
42: #endif
43:
44:
45: /*
46: ** Provide the ability to override linkage features of the interface.
47: */
48: #ifndef SQLITE_EXTERN
49: # define SQLITE_EXTERN extern
50: #endif
51: #ifndef SQLITE_API
52: # define SQLITE_API
53: #endif
54: #ifndef SQLITE_CDECL
55: # define SQLITE_CDECL
56: #endif
57: #ifndef SQLITE_APICALL
58: # define SQLITE_APICALL
59: #endif
60: #ifndef SQLITE_STDCALL
61: # define SQLITE_STDCALL SQLITE_APICALL
62: #endif
63: #ifndef SQLITE_CALLBACK
64: # define SQLITE_CALLBACK
65: #endif
66: #ifndef SQLITE_SYSAPI
67: # define SQLITE_SYSAPI
68: #endif
69:
70: /*
71: ** These no-op macros are used in front of interfaces to mark those
72: ** interfaces as either deprecated or experimental. New applications
73: ** should not use deprecated interfaces - they are supported for backwards
74: ** compatibility only. Application writers should be aware that
75: ** experimental interfaces are subject to change in point releases.
76: **
77: ** These macros used to resolve to various kinds of compiler magic that
78: ** would generate warning messages when they were used. But that
79: ** compiler magic ended up generating such a flurry of bug reports
80: ** that we have taken it all out and gone back to using simple
81: ** noop macros.
82: */
83: #define SQLITE_DEPRECATED
84: #define SQLITE_EXPERIMENTAL
85:
86: /*
87: ** Ensure these symbols were not defined by some previous header file.
88: */
89: #ifdef SQLITE_VERSION
90: # undef SQLITE_VERSION
91: #endif
92: #ifdef SQLITE_VERSION_NUMBER
93: # undef SQLITE_VERSION_NUMBER
94: #endif
95:
96: /*
97: ** CAPI3REF: Compile-Time Library Version Numbers
98: **
99: ** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header
100: ** evaluates to a string literal that is the SQLite version in the
101: ** format "X.Y.Z" where X is the major version number (always 3 for
102: ** SQLite3) and Y is the minor version number and Z is the release number.)^
103: ** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer
104: ** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same
105: ** numbers used in [SQLITE_VERSION].)^
106: ** The SQLITE_VERSION_NUMBER for any given release of SQLite will also
107: ** be larger than the release from which it is derived. Either Y will
108: ** be held constant and Z will be incremented or else Y will be incremented
109: ** and Z will be reset to zero.
110: **
111: ** Since version 3.6.18, SQLite source code has been stored in the
112: ** <a href="http://www.fossil-scm.org/">Fossil configuration management
113: ** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to
114: ** a string which identifies a particular check-in of SQLite
115: ** within its configuration management system. ^The SQLITE_SOURCE_ID
116: ** string contains the date and time of the check-in (UTC) and an SHA1
117: ** hash of the entire source tree.
118: **
119: ** See also: [sqlite3_libversion()],
120: ** [sqlite3_libversion_number()], [sqlite3_sourceid()],
121: ** [sqlite_version()] and [sqlite_source_id()].
122: */
123: #define SQLITE_VERSION "3.14.2"
124: #define SQLITE_VERSION_NUMBER 3014002
125: #define SQLITE_SOURCE_ID "2016-09-12 18:50:49 29dbef4b8585f753861a36d6dd102ca634197bd6"
126:
127: /*
128: ** CAPI3REF: Run-Time Library Version Numbers
129: ** KEYWORDS: sqlite3_version, sqlite3_sourceid
130: **
131: ** These interfaces provide the same information as the [SQLITE_VERSION],
132: ** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros
133: ** but are associated with the library instead of the header file. ^(Cautious
134: ** programmers might include assert() statements in their application to
135: ** verify that values returned by these interfaces match the macros in
136: ** the header, and thus ensure that the application is
137: ** compiled with matching library and header files.
138: **
139: ** <blockquote><pre>
140: ** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
141: ** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 );
142: ** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
143: ** </pre></blockquote>)^
144: **
145: ** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION]
146: ** macro. ^The sqlite3_libversion() function returns a pointer to the
147: ** to the sqlite3_version[] string constant. The sqlite3_libversion()
148: ** function is provided for use in DLLs since DLL users usually do not have
149: ** direct access to string constants within the DLL. ^The
150: ** sqlite3_libversion_number() function returns an integer equal to
151: ** [SQLITE_VERSION_NUMBER]. ^The sqlite3_sourceid() function returns
152: ** a pointer to a string constant whose value is the same as the
153: ** [SQLITE_SOURCE_ID] C preprocessor macro.
154: **
155: ** See also: [sqlite_version()] and [sqlite_source_id()].
156: */
157: SQLITE_API SQLITE_EXTERN const char sqlite3_version[];
158: SQLITE_API const char *sqlite3_libversion(void);
159: SQLITE_API const char *sqlite3_sourceid(void);
160: SQLITE_API int sqlite3_libversion_number(void);
161:
162: /*
163: ** CAPI3REF: Run-Time Library Compilation Options Diagnostics
164: **
165: ** ^The sqlite3_compileoption_used() function returns 0 or 1
166: ** indicating whether the specified option was defined at
167: ** compile time. ^The SQLITE_ prefix may be omitted from the
168: ** option name passed to sqlite3_compileoption_used().
169: **
170: ** ^The sqlite3_compileoption_get() function allows iterating
171: ** over the list of options that were defined at compile time by
172: ** returning the N-th compile time option string. ^If N is out of range,
173: ** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_
174: ** prefix is omitted from any strings returned by
175: ** sqlite3_compileoption_get().
176: **
177: ** ^Support for the diagnostic functions sqlite3_compileoption_used()
178: ** and sqlite3_compileoption_get() may be omitted by specifying the
179: ** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time.
180: **
181: ** See also: SQL functions [sqlite_compileoption_used()] and
182: ** [sqlite_compileoption_get()] and the [compile_options pragma].
183: */
184: #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
185: SQLITE_API int sqlite3_compileoption_used(const char *zOptName);
186: SQLITE_API const char *sqlite3_compileoption_get(int N);
187: #endif
188:
189: /*
190: ** CAPI3REF: Test To See If The Library Is Threadsafe
191: **
192: ** ^The sqlite3_threadsafe() function returns zero if and only if
193: ** SQLite was compiled with mutexing code omitted due to the
194: ** [SQLITE_THREADSAFE] compile-time option being set to 0.
195: **
196: ** SQLite can be compiled with or without mutexes. When
197: ** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
198: ** are enabled and SQLite is threadsafe. When the
199: ** [SQLITE_THREADSAFE] macro is 0,
200: ** the mutexes are omitted. Without the mutexes, it is not safe
201: ** to use SQLite concurrently from more than one thread.
202: **
203: ** Enabling mutexes incurs a measurable performance penalty.
204: ** So if speed is of utmost importance, it makes sense to disable
205: ** the mutexes. But for maximum safety, mutexes should be enabled.
206: ** ^The default behavior is for mutexes to be enabled.
207: **
208: ** This interface can be used by an application to make sure that the
209: ** version of SQLite that it is linking against was compiled with
210: ** the desired setting of the [SQLITE_THREADSAFE] macro.
211: **
212: ** This interface only reports on the compile-time mutex setting
213: ** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with
214: ** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
215: ** can be fully or partially disabled using a call to [sqlite3_config()]
216: ** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD],
217: ** or [SQLITE_CONFIG_SERIALIZED]. ^(The return value of the
218: ** sqlite3_threadsafe() function shows only the compile-time setting of
219: ** thread safety, not any run-time changes to that setting made by
220: ** sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
221: ** is unchanged by calls to sqlite3_config().)^
222: **
223: ** See the [threading mode] documentation for additional information.
224: */
225: SQLITE_API int sqlite3_threadsafe(void);
226:
227: /*
228: ** CAPI3REF: Database Connection Handle
229: ** KEYWORDS: {database connection} {database connections}
230: **
231: ** Each open SQLite database is represented by a pointer to an instance of
232: ** the opaque structure named "sqlite3". It is useful to think of an sqlite3
233: ** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and
234: ** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
235: ** and [sqlite3_close_v2()] are its destructors. There are many other
236: ** interfaces (such as
237: ** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
238: ** [sqlite3_busy_timeout()] to name but three) that are methods on an
239: ** sqlite3 object.
240: */
241: typedef struct sqlite3 sqlite3;
242:
243: /*
244: ** CAPI3REF: 64-Bit Integer Types
245: ** KEYWORDS: sqlite_int64 sqlite_uint64
246: **
247: ** Because there is no cross-platform way to specify 64-bit integer types
248: ** SQLite includes typedefs for 64-bit signed and unsigned integers.
249: **
250: ** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
251: ** The sqlite_int64 and sqlite_uint64 types are supported for backwards
252: ** compatibility only.
253: **
254: ** ^The sqlite3_int64 and sqlite_int64 types can store integer values
255: ** between -9223372036854775808 and +9223372036854775807 inclusive. ^The
256: ** sqlite3_uint64 and sqlite_uint64 types can store integer values
257: ** between 0 and +18446744073709551615 inclusive.
258: */
259: #ifdef SQLITE_INT64_TYPE
260: typedef SQLITE_INT64_TYPE sqlite_int64;
261: typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
262: #elif defined(_MSC_VER) || defined(__BORLANDC__)
263: typedef __int64 sqlite_int64;
264: typedef unsigned __int64 sqlite_uint64;
265: #else
266: typedef long long int sqlite_int64;
267: typedef unsigned long long int sqlite_uint64;
268: #endif
269: typedef sqlite_int64 sqlite3_int64;
270: typedef sqlite_uint64 sqlite3_uint64;
271:
272: /*
273: ** If compiling for a processor that lacks floating point support,
274: ** substitute integer for floating-point.
275: */
276: #ifdef SQLITE_OMIT_FLOATING_POINT
277: # define double sqlite3_int64
278: #endif
279:
280: /*
281: ** CAPI3REF: Closing A Database Connection
282: ** DESTRUCTOR: sqlite3
283: **
284: ** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors
285: ** for the [sqlite3] object.
286: ** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if
287: ** the [sqlite3] object is successfully destroyed and all associated
288: ** resources are deallocated.
289: **
290: ** ^If the database connection is associated with unfinalized prepared
291: ** statements or unfinished sqlite3_backup objects then sqlite3_close()
292: ** will leave the database connection open and return [SQLITE_BUSY].
293: ** ^If sqlite3_close_v2() is called with unfinalized prepared statements
294: ** and/or unfinished sqlite3_backups, then the database connection becomes
295: ** an unusable "zombie" which will automatically be deallocated when the
296: ** last prepared statement is finalized or the last sqlite3_backup is
297: ** finished. The sqlite3_close_v2() interface is intended for use with
298: ** host languages that are garbage collected, and where the order in which
299: ** destructors are called is arbitrary.
300: **
301: ** Applications should [sqlite3_finalize | finalize] all [prepared statements],
302: ** [sqlite3_blob_close | close] all [BLOB handles], and
303: ** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated
304: ** with the [sqlite3] object prior to attempting to close the object. ^If
305: ** sqlite3_close_v2() is called on a [database connection] that still has
306: ** outstanding [prepared statements], [BLOB handles], and/or
307: ** [sqlite3_backup] objects then it returns [SQLITE_OK] and the deallocation
308: ** of resources is deferred until all [prepared statements], [BLOB handles],
309: ** and [sqlite3_backup] objects are also destroyed.
310: **
311: ** ^If an [sqlite3] object is destroyed while a transaction is open,
312: ** the transaction is automatically rolled back.
313: **
314: ** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)]
315: ** must be either a NULL
316: ** pointer or an [sqlite3] object pointer obtained
317: ** from [sqlite3_open()], [sqlite3_open16()], or
318: ** [sqlite3_open_v2()], and not previously closed.
319: ** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer
320: ** argument is a harmless no-op.
321: */
322: SQLITE_API int sqlite3_close(sqlite3*);
323: SQLITE_API int sqlite3_close_v2(sqlite3*);
324:
325: /*
326: ** The type for a callback function.
327: ** This is legacy and deprecated. It is included for historical
328: ** compatibility and is not documented.
329: */
330: typedef int (*sqlite3_callback)(void*,int,char**, char**);
331:
332: /*
333: ** CAPI3REF: One-Step Query Execution Interface
334: ** METHOD: sqlite3
335: **
336: ** The sqlite3_exec() interface is a convenience wrapper around
337: ** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
338: ** that allows an application to run multiple statements of SQL
339: ** without having to use a lot of C code.
340: **
341: ** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
342: ** semicolon-separate SQL statements passed into its 2nd argument,
343: ** in the context of the [database connection] passed in as its 1st
344: ** argument. ^If the callback function of the 3rd argument to
345: ** sqlite3_exec() is not NULL, then it is invoked for each result row
346: ** coming out of the evaluated SQL statements. ^The 4th argument to
347: ** sqlite3_exec() is relayed through to the 1st argument of each
348: ** callback invocation. ^If the callback pointer to sqlite3_exec()
349: ** is NULL, then no callback is ever invoked and result rows are
350: ** ignored.
351: **
352: ** ^If an error occurs while evaluating the SQL statements passed into
353: ** sqlite3_exec(), then execution of the current statement stops and
354: ** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec()
355: ** is not NULL then any error message is written into memory obtained
356: ** from [sqlite3_malloc()] and passed back through the 5th parameter.
357: ** To avoid memory leaks, the application should invoke [sqlite3_free()]
358: ** on error message strings returned through the 5th parameter of
359: ** sqlite3_exec() after the error message string is no longer needed.
360: ** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
361: ** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
362: ** NULL before returning.
363: **
364: ** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
365: ** routine returns SQLITE_ABORT without invoking the callback again and
366: ** without running any subsequent SQL statements.
367: **
368: ** ^The 2nd argument to the sqlite3_exec() callback function is the
369: ** number of columns in the result. ^The 3rd argument to the sqlite3_exec()
370: ** callback is an array of pointers to strings obtained as if from
371: ** [sqlite3_column_text()], one for each column. ^If an element of a
372: ** result row is NULL then the corresponding string pointer for the
373: ** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the
374: ** sqlite3_exec() callback is an array of pointers to strings where each
375: ** entry represents the name of corresponding result column as obtained
376: ** from [sqlite3_column_name()].
377: **
378: ** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
379: ** to an empty string, or a pointer that contains only whitespace and/or
380: ** SQL comments, then no SQL statements are evaluated and the database
381: ** is not changed.
382: **
383: ** Restrictions:
384: **
385: ** <ul>
386: ** <li> The application must ensure that the 1st parameter to sqlite3_exec()
387: ** is a valid and open [database connection].
388: ** <li> The application must not close the [database connection] specified by
389: ** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
390: ** <li> The application must not modify the SQL statement text passed into
391: ** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
392: ** </ul>
393: */
394: SQLITE_API int sqlite3_exec(
395: sqlite3*, /* An open database */
396: const char *sql, /* SQL to be evaluated */
397: int (*callback)(void*,int,char**,char**), /* Callback function */
398: void *, /* 1st argument to callback */
399: char **errmsg /* Error msg written here */
400: );
401:
402: /*
403: ** CAPI3REF: Result Codes
404: ** KEYWORDS: {result code definitions}
405: **
406: ** Many SQLite functions return an integer result code from the set shown
407: ** here in order to indicate success or failure.
408: **
409: ** New error codes may be added in future versions of SQLite.
410: **
411: ** See also: [extended result code definitions]
412: */
413: #define SQLITE_OK 0 /* Successful result */
414: /* beginning-of-error-codes */
415: #define SQLITE_ERROR 1 /* SQL error or missing database */
416: #define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */
417: #define SQLITE_PERM 3 /* Access permission denied */
418: #define SQLITE_ABORT 4 /* Callback routine requested an abort */
419: #define SQLITE_BUSY 5 /* The database file is locked */
420: #define SQLITE_LOCKED 6 /* A table in the database is locked */
421: #define SQLITE_NOMEM 7 /* A malloc() failed */
422: #define SQLITE_READONLY 8 /* Attempt to write a readonly database */
423: #define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/
424: #define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */
425: #define SQLITE_CORRUPT 11 /* The database disk image is malformed */
426: #define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */
427: #define SQLITE_FULL 13 /* Insertion failed because database is full */
428: #define SQLITE_CANTOPEN 14 /* Unable to open the database file */
429: #define SQLITE_PROTOCOL 15 /* Database lock protocol error */
430: #define SQLITE_EMPTY 16 /* Database is empty */
431: #define SQLITE_SCHEMA 17 /* The database schema changed */
432: #define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */
433: #define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */
434: #define SQLITE_MISMATCH 20 /* Data type mismatch */
435: #define SQLITE_MISUSE 21 /* Library used incorrectly */
436: #define SQLITE_NOLFS 22 /* Uses OS features not supported on host */
437: #define SQLITE_AUTH 23 /* Authorization denied */
438: #define SQLITE_FORMAT 24 /* Auxiliary database format error */
439: #define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */
440: #define SQLITE_NOTADB 26 /* File opened that is not a database file */
441: #define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */
442: #define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */
443: #define SQLITE_ROW 100 /* sqlite3_step() has another row ready */
444: #define SQLITE_DONE 101 /* sqlite3_step() has finished executing */
445: /* end-of-error-codes */
446:
447: /*
448: ** CAPI3REF: Extended Result Codes
449: ** KEYWORDS: {extended result code definitions}
450: **
451: ** In its default configuration, SQLite API routines return one of 30 integer
452: ** [result codes]. However, experience has shown that many of
453: ** these result codes are too coarse-grained. They do not provide as
454: ** much information about problems as programmers might like. In an effort to
455: ** address this, newer versions of SQLite (version 3.3.8 and later) include
456: ** support for additional result codes that provide more detailed information
457: ** about errors. These [extended result codes] are enabled or disabled
458: ** on a per database connection basis using the
459: ** [sqlite3_extended_result_codes()] API. Or, the extended code for
460: ** the most recent error can be obtained using
461: ** [sqlite3_extended_errcode()].
462: */
463: #define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8))
464: #define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8))
465: #define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8))
466: #define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8))
467: #define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8))
468: #define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8))
469: #define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8))
470: #define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8))
471: #define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8))
472: #define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8))
473: #define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8))
474: #define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8))
475: #define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8))
476: #define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
477: #define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8))
478: #define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8))
479: #define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8))
480: #define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8))
481: #define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8))
482: #define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8))
483: #define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8))
484: #define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8))
485: #define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8))
486: #define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8))
487: #define SQLITE_IOERR_GETTEMPPATH (SQLITE_IOERR | (25<<8))
488: #define SQLITE_IOERR_CONVPATH (SQLITE_IOERR | (26<<8))
489: #define SQLITE_IOERR_VNODE (SQLITE_IOERR | (27<<8))
490: #define SQLITE_IOERR_AUTH (SQLITE_IOERR | (28<<8))
491: #define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8))
492: #define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8))
493: #define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY | (2<<8))
494: #define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8))
495: #define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8))
496: #define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8))
497: #define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN | (4<<8))
498: #define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8))
499: #define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8))
500: #define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8))
501: #define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8))
502: #define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8))
503: #define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8))
504: #define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8))
505: #define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8))
506: #define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8))
507: #define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8))
508: #define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8))
509: #define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8))
510: #define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8))
511: #define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8))
512: #define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8))
513: #define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT |(10<<8))
514: #define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8))
515: #define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8))
516: #define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING | (1<<8))
517: #define SQLITE_AUTH_USER (SQLITE_AUTH | (1<<8))
518: #define SQLITE_OK_LOAD_PERMANENTLY (SQLITE_OK | (1<<8))
519:
520: /*
521: ** CAPI3REF: Flags For File Open Operations
522: **
523: ** These bit values are intended for use in the
524: ** 3rd parameter to the [sqlite3_open_v2()] interface and
525: ** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
526: */
527: #define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */
528: #define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */
529: #define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */
530: #define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */
531: #define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */
532: #define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */
533: #define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */
534: #define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */
535: #define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */
536: #define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */
537: #define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */
538: #define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */
539: #define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */
540: #define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */
541: #define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */
542: #define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */
543: #define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */
544: #define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */
545: #define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */
546: #define SQLITE_OPEN_WAL 0x00080000 /* VFS only */
547:
548: /* Reserved: 0x00F00000 */
549:
550: /*
551: ** CAPI3REF: Device Characteristics
552: **
553: ** The xDeviceCharacteristics method of the [sqlite3_io_methods]
554: ** object returns an integer which is a vector of these
555: ** bit values expressing I/O characteristics of the mass storage
556: ** device that holds the file that the [sqlite3_io_methods]
557: ** refers to.
558: **
559: ** The SQLITE_IOCAP_ATOMIC property means that all writes of
560: ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
561: ** mean that writes of blocks that are nnn bytes in size and
562: ** are aligned to an address which is an integer multiple of
563: ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
564: ** that when data is appended to a file, the data is appended
565: ** first then the size of the file is extended, never the other
566: ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
567: ** information is written to disk in the same order as calls
568: ** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
569: ** after reboot following a crash or power loss, the only bytes in a
570: ** file that were written at the application level might have changed
571: ** and that adjacent bytes, even bytes within the same sector are
572: ** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN
573: ** flag indicate that a file cannot be deleted when open. The
574: ** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on
575: ** read-only media and cannot be changed even by processes with
576: ** elevated privileges.
577: */
578: #define SQLITE_IOCAP_ATOMIC 0x00000001
579: #define SQLITE_IOCAP_ATOMIC512 0x00000002
580: #define SQLITE_IOCAP_ATOMIC1K 0x00000004
581: #define SQLITE_IOCAP_ATOMIC2K 0x00000008
582: #define SQLITE_IOCAP_ATOMIC4K 0x00000010
583: #define SQLITE_IOCAP_ATOMIC8K 0x00000020
584: #define SQLITE_IOCAP_ATOMIC16K 0x00000040
585: #define SQLITE_IOCAP_ATOMIC32K 0x00000080
586: #define SQLITE_IOCAP_ATOMIC64K 0x00000100
587: #define SQLITE_IOCAP_SAFE_APPEND 0x00000200
588: #define SQLITE_IOCAP_SEQUENTIAL 0x00000400
589: #define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800
590: #define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000
591: #define SQLITE_IOCAP_IMMUTABLE 0x00002000
592:
593: /*
594: ** CAPI3REF: File Locking Levels
595: **
596: ** SQLite uses one of these integer values as the second
597: ** argument to calls it makes to the xLock() and xUnlock() methods
598: ** of an [sqlite3_io_methods] object.
599: */
600: #define SQLITE_LOCK_NONE 0
601: #define SQLITE_LOCK_SHARED 1
602: #define SQLITE_LOCK_RESERVED 2
603: #define SQLITE_LOCK_PENDING 3
604: #define SQLITE_LOCK_EXCLUSIVE 4
605:
606: /*
607: ** CAPI3REF: Synchronization Type Flags
608: **
609: ** When SQLite invokes the xSync() method of an
610: ** [sqlite3_io_methods] object it uses a combination of
611: ** these integer values as the second argument.
612: **
613: ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
614: ** sync operation only needs to flush data to mass storage. Inode
615: ** information need not be flushed. If the lower four bits of the flag
616: ** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
617: ** If the lower four bits equal SQLITE_SYNC_FULL, that means
618: ** to use Mac OS X style fullsync instead of fsync().
619: **
620: ** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
621: ** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
622: ** settings. The [synchronous pragma] determines when calls to the
623: ** xSync VFS method occur and applies uniformly across all platforms.
624: ** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
625: ** energetic or rigorous or forceful the sync operations are and
626: ** only make a difference on Mac OSX for the default SQLite code.
627: ** (Third-party VFS implementations might also make the distinction
628: ** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
629: ** operating systems natively supported by SQLite, only Mac OSX
630: ** cares about the difference.)
631: */
632: #define SQLITE_SYNC_NORMAL 0x00002
633: #define SQLITE_SYNC_FULL 0x00003
634: #define SQLITE_SYNC_DATAONLY 0x00010
635:
636: /*
637: ** CAPI3REF: OS Interface Open File Handle
638: **
639: ** An [sqlite3_file] object represents an open file in the
640: ** [sqlite3_vfs | OS interface layer]. Individual OS interface
641: ** implementations will
642: ** want to subclass this object by appending additional fields
643: ** for their own use. The pMethods entry is a pointer to an
644: ** [sqlite3_io_methods] object that defines methods for performing
645: ** I/O operations on the open file.
646: */
647: typedef struct sqlite3_file sqlite3_file;
648: struct sqlite3_file {
649: const struct sqlite3_io_methods *pMethods; /* Methods for an open file */
650: };
651:
652: /*
653: ** CAPI3REF: OS Interface File Virtual Methods Object
654: **
655: ** Every file opened by the [sqlite3_vfs.xOpen] method populates an
656: ** [sqlite3_file] object (or, more commonly, a subclass of the
657: ** [sqlite3_file] object) with a pointer to an instance of this object.
658: ** This object defines the methods used to perform various operations
659: ** against the open file represented by the [sqlite3_file] object.
660: **
661: ** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element
662: ** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
663: ** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The
664: ** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
665: ** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
666: ** to NULL.
667: **
668: ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
669: ** [SQLITE_SYNC_FULL]. The first choice is the normal fsync().
670: ** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY]
671: ** flag may be ORed in to indicate that only the data of the file
672: ** and not its inode needs to be synced.
673: **
674: ** The integer values to xLock() and xUnlock() are one of
675: ** <ul>
676: ** <li> [SQLITE_LOCK_NONE],
677: ** <li> [SQLITE_LOCK_SHARED],
678: ** <li> [SQLITE_LOCK_RESERVED],
679: ** <li> [SQLITE_LOCK_PENDING], or
680: ** <li> [SQLITE_LOCK_EXCLUSIVE].
681: ** </ul>
682: ** xLock() increases the lock. xUnlock() decreases the lock.
683: ** The xCheckReservedLock() method checks whether any database connection,
684: ** either in this process or in some other process, is holding a RESERVED,
685: ** PENDING, or EXCLUSIVE lock on the file. It returns true
686: ** if such a lock exists and false otherwise.
687: **
688: ** The xFileControl() method is a generic interface that allows custom
689: ** VFS implementations to directly control an open file using the
690: ** [sqlite3_file_control()] interface. The second "op" argument is an
691: ** integer opcode. The third argument is a generic pointer intended to
692: ** point to a structure that may contain arguments or space in which to
693: ** write return values. Potential uses for xFileControl() might be
694: ** functions to enable blocking locks with timeouts, to change the
695: ** locking strategy (for example to use dot-file locks), to inquire
696: ** about the status of a lock, or to break stale locks. The SQLite
697: ** core reserves all opcodes less than 100 for its own use.
698: ** A [file control opcodes | list of opcodes] less than 100 is available.
699: ** Applications that define a custom xFileControl method should use opcodes
700: ** greater than 100 to avoid conflicts. VFS implementations should
701: ** return [SQLITE_NOTFOUND] for file control opcodes that they do not
702: ** recognize.
703: **
704: ** The xSectorSize() method returns the sector size of the
705: ** device that underlies the file. The sector size is the
706: ** minimum write that can be performed without disturbing
707: ** other bytes in the file. The xDeviceCharacteristics()
708: ** method returns a bit vector describing behaviors of the
709: ** underlying device:
710: **
711: ** <ul>
712: ** <li> [SQLITE_IOCAP_ATOMIC]
713: ** <li> [SQLITE_IOCAP_ATOMIC512]
714: ** <li> [SQLITE_IOCAP_ATOMIC1K]
715: ** <li> [SQLITE_IOCAP_ATOMIC2K]
716: ** <li> [SQLITE_IOCAP_ATOMIC4K]
717: ** <li> [SQLITE_IOCAP_ATOMIC8K]
718: ** <li> [SQLITE_IOCAP_ATOMIC16K]
719: ** <li> [SQLITE_IOCAP_ATOMIC32K]
720: ** <li> [SQLITE_IOCAP_ATOMIC64K]
721: ** <li> [SQLITE_IOCAP_SAFE_APPEND]
722: ** <li> [SQLITE_IOCAP_SEQUENTIAL]
723: ** </ul>
724: **
725: ** The SQLITE_IOCAP_ATOMIC property means that all writes of
726: ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
727: ** mean that writes of blocks that are nnn bytes in size and
728: ** are aligned to an address which is an integer multiple of
729: ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
730: ** that when data is appended to a file, the data is appended
731: ** first then the size of the file is extended, never the other
732: ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
733: ** information is written to disk in the same order as calls
734: ** to xWrite().
735: **
736: ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
737: ** in the unread portions of the buffer with zeros. A VFS that
738: ** fails to zero-fill short reads might seem to work. However,
739: ** failure to zero-fill short reads will eventually lead to
740: ** database corruption.
741: */
742: typedef struct sqlite3_io_methods sqlite3_io_methods;
743: struct sqlite3_io_methods {
744: int iVersion;
745: int (*xClose)(sqlite3_file*);
746: int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
747: int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
748: int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
749: int (*xSync)(sqlite3_file*, int flags);
750: int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
751: int (*xLock)(sqlite3_file*, int);
752: int (*xUnlock)(sqlite3_file*, int);
753: int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
754: int (*xFileControl)(sqlite3_file*, int op, void *pArg);
755: int (*xSectorSize)(sqlite3_file*);
756: int (*xDeviceCharacteristics)(sqlite3_file*);
757: /* Methods above are valid for version 1 */
758: int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
759: int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
760: void (*xShmBarrier)(sqlite3_file*);
761: int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
762: /* Methods above are valid for version 2 */
763: int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp);
764: int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p);
765: /* Methods above are valid for version 3 */
766: /* Additional methods may be added in future releases */
767: };
768:
769: /*
770: ** CAPI3REF: Standard File Control Opcodes
771: ** KEYWORDS: {file control opcodes} {file control opcode}
772: **
773: ** These integer constants are opcodes for the xFileControl method
774: ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
775: ** interface.
776: **
777: ** <ul>
778: ** <li>[[SQLITE_FCNTL_LOCKSTATE]]
779: ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This
780: ** opcode causes the xFileControl method to write the current state of
781: ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
782: ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
783: ** into an integer that the pArg argument points to. This capability
784: ** is used during testing and is only available when the SQLITE_TEST
785: ** compile-time option is used.
786: **
787: ** <li>[[SQLITE_FCNTL_SIZE_HINT]]
788: ** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
789: ** layer a hint of how large the database file will grow to be during the
790: ** current transaction. This hint is not guaranteed to be accurate but it
791: ** is often close. The underlying VFS might choose to preallocate database
792: ** file space based on this hint in order to help writes to the database
793: ** file run faster.
794: **
795: ** <li>[[SQLITE_FCNTL_CHUNK_SIZE]]
796: ** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
797: ** extends and truncates the database file in chunks of a size specified
798: ** by the user. The fourth argument to [sqlite3_file_control()] should
799: ** point to an integer (type int) containing the new chunk-size to use
800: ** for the nominated database. Allocating database file space in large
801: ** chunks (say 1MB at a time), may reduce file-system fragmentation and
802: ** improve performance on some systems.
803: **
804: ** <li>[[SQLITE_FCNTL_FILE_POINTER]]
805: ** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
806: ** to the [sqlite3_file] object associated with a particular database
807: ** connection. See also [SQLITE_FCNTL_JOURNAL_POINTER].
808: **
809: ** <li>[[SQLITE_FCNTL_JOURNAL_POINTER]]
810: ** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer
811: ** to the [sqlite3_file] object associated with the journal file (either
812: ** the [rollback journal] or the [write-ahead log]) for a particular database
813: ** connection. See also [SQLITE_FCNTL_FILE_POINTER].
814: **
815: ** <li>[[SQLITE_FCNTL_SYNC_OMITTED]]
816: ** No longer in use.
817: **
818: ** <li>[[SQLITE_FCNTL_SYNC]]
819: ** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and
820: ** sent to the VFS immediately before the xSync method is invoked on a
821: ** database file descriptor. Or, if the xSync method is not invoked
822: ** because the user has configured SQLite with
823: ** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place
824: ** of the xSync method. In most cases, the pointer argument passed with
825: ** this file-control is NULL. However, if the database file is being synced
826: ** as part of a multi-database commit, the argument points to a nul-terminated
827: ** string containing the transactions master-journal file name. VFSes that
828: ** do not need this signal should silently ignore this opcode. Applications
829: ** should not call [sqlite3_file_control()] with this opcode as doing so may
830: ** disrupt the operation of the specialized VFSes that do require it.
831: **
832: ** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]]
833: ** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite
834: ** and sent to the VFS after a transaction has been committed immediately
835: ** but before the database is unlocked. VFSes that do not need this signal
836: ** should silently ignore this opcode. Applications should not call
837: ** [sqlite3_file_control()] with this opcode as doing so may disrupt the
838: ** operation of the specialized VFSes that do require it.
839: **
840: ** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]]
841: ** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
842: ** retry counts and intervals for certain disk I/O operations for the
843: ** windows [VFS] in order to provide robustness in the presence of
844: ** anti-virus programs. By default, the windows VFS will retry file read,
845: ** file write, and file delete operations up to 10 times, with a delay
846: ** of 25 milliseconds before the first retry and with the delay increasing
847: ** by an additional 25 milliseconds with each subsequent retry. This
848: ** opcode allows these two values (10 retries and 25 milliseconds of delay)
849: ** to be adjusted. The values are changed for all database connections
850: ** within the same process. The argument is a pointer to an array of two
851: ** integers where the first integer i the new retry count and the second
852: ** integer is the delay. If either integer is negative, then the setting
853: ** is not changed but instead the prior value of that setting is written
854: ** into the array entry, allowing the current retry settings to be
855: ** interrogated. The zDbName parameter is ignored.
856: **
857: ** <li>[[SQLITE_FCNTL_PERSIST_WAL]]
858: ** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
859: ** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary
860: ** write ahead log and shared memory files used for transaction control
861: ** are automatically deleted when the latest connection to the database
862: ** closes. Setting persistent WAL mode causes those files to persist after
863: ** close. Persisting the files is useful when other processes that do not
864: ** have write permission on the directory containing the database file want
865: ** to read the database file, as the WAL and shared memory files must exist
866: ** in order for the database to be readable. The fourth parameter to
867: ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
868: ** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
869: ** WAL mode. If the integer is -1, then it is overwritten with the current
870: ** WAL persistence setting.
871: **
872: ** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]]
873: ** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
874: ** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting
875: ** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
876: ** xDeviceCharacteristics methods. The fourth parameter to
877: ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
878: ** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
879: ** mode. If the integer is -1, then it is overwritten with the current
880: ** zero-damage mode setting.
881: **
882: ** <li>[[SQLITE_FCNTL_OVERWRITE]]
883: ** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
884: ** a write transaction to indicate that, unless it is rolled back for some
885: ** reason, the entire database file will be overwritten by the current
886: ** transaction. This is used by VACUUM operations.
887: **
888: ** <li>[[SQLITE_FCNTL_VFSNAME]]
889: ** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
890: ** all [VFSes] in the VFS stack. The names are of all VFS shims and the
891: ** final bottom-level VFS are written into memory obtained from
892: ** [sqlite3_malloc()] and the result is stored in the char* variable
893: ** that the fourth parameter of [sqlite3_file_control()] points to.
894: ** The caller is responsible for freeing the memory when done. As with
895: ** all file-control actions, there is no guarantee that this will actually
896: ** do anything. Callers should initialize the char* variable to a NULL
897: ** pointer in case this file-control is not implemented. This file-control
898: ** is intended for diagnostic use only.
899: **
900: ** <li>[[SQLITE_FCNTL_VFS_POINTER]]
901: ** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level
902: ** [VFSes] currently in use. ^(The argument X in
903: ** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be
904: ** of type "[sqlite3_vfs] **". This opcodes will set *X
905: ** to a pointer to the top-level VFS.)^
906: ** ^When there are multiple VFS shims in the stack, this opcode finds the
907: ** upper-most shim only.
908: **
909: ** <li>[[SQLITE_FCNTL_PRAGMA]]
910: ** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA]
911: ** file control is sent to the open [sqlite3_file] object corresponding
912: ** to the database file to which the pragma statement refers. ^The argument
913: ** to the [SQLITE_FCNTL_PRAGMA] file control is an array of
914: ** pointers to strings (char**) in which the second element of the array
915: ** is the name of the pragma and the third element is the argument to the
916: ** pragma or NULL if the pragma has no argument. ^The handler for an
917: ** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element
918: ** of the char** argument point to a string obtained from [sqlite3_mprintf()]
919: ** or the equivalent and that string will become the result of the pragma or
920: ** the error message if the pragma fails. ^If the
921: ** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal
922: ** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA]
923: ** file control returns [SQLITE_OK], then the parser assumes that the
924: ** VFS has handled the PRAGMA itself and the parser generates a no-op
925: ** prepared statement if result string is NULL, or that returns a copy
926: ** of the result string if the string is non-NULL.
927: ** ^If the [SQLITE_FCNTL_PRAGMA] file control returns
928: ** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means
929: ** that the VFS encountered an error while handling the [PRAGMA] and the
930: ** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA]
931: ** file control occurs at the beginning of pragma statement analysis and so
932: ** it is able to override built-in [PRAGMA] statements.
933: **
934: ** <li>[[SQLITE_FCNTL_BUSYHANDLER]]
935: ** ^The [SQLITE_FCNTL_BUSYHANDLER]
936: ** file-control may be invoked by SQLite on the database file handle
937: ** shortly after it is opened in order to provide a custom VFS with access
938: ** to the connections busy-handler callback. The argument is of type (void **)
939: ** - an array of two (void *) values. The first (void *) actually points
940: ** to a function of type (int (*)(void *)). In order to invoke the connections
941: ** busy-handler, this function should be invoked with the second (void *) in
942: ** the array as the only argument. If it returns non-zero, then the operation
943: ** should be retried. If it returns zero, the custom VFS should abandon the
944: ** current operation.
945: **
946: ** <li>[[SQLITE_FCNTL_TEMPFILENAME]]
947: ** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control
948: ** to have SQLite generate a
949: ** temporary filename using the same algorithm that is followed to generate
950: ** temporary filenames for TEMP tables and other internal uses. The
951: ** argument should be a char** which will be filled with the filename
952: ** written into memory obtained from [sqlite3_malloc()]. The caller should
953: ** invoke [sqlite3_free()] on the result to avoid a memory leak.
954: **
955: ** <li>[[SQLITE_FCNTL_MMAP_SIZE]]
956: ** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the
957: ** maximum number of bytes that will be used for memory-mapped I/O.
958: ** The argument is a pointer to a value of type sqlite3_int64 that
959: ** is an advisory maximum number of bytes in the file to memory map. The
960: ** pointer is overwritten with the old value. The limit is not changed if
961: ** the value originally pointed to is negative, and so the current limit
962: ** can be queried by passing in a pointer to a negative number. This
963: ** file-control is used internally to implement [PRAGMA mmap_size].
964: **
965: ** <li>[[SQLITE_FCNTL_TRACE]]
966: ** The [SQLITE_FCNTL_TRACE] file control provides advisory information
967: ** to the VFS about what the higher layers of the SQLite stack are doing.
968: ** This file control is used by some VFS activity tracing [shims].
969: ** The argument is a zero-terminated string. Higher layers in the
970: ** SQLite stack may generate instances of this file control if
971: ** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled.
972: **
973: ** <li>[[SQLITE_FCNTL_HAS_MOVED]]
974: ** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a
975: ** pointer to an integer and it writes a boolean into that integer depending
976: ** on whether or not the file has been renamed, moved, or deleted since it
977: ** was first opened.
978: **
979: ** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]]
980: ** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This
981: ** opcode causes the xFileControl method to swap the file handle with the one
982: ** pointed to by the pArg argument. This capability is used during testing
983: ** and only needs to be supported when SQLITE_TEST is defined.
984: **
985: ** <li>[[SQLITE_FCNTL_WAL_BLOCK]]
986: ** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might
987: ** be advantageous to block on the next WAL lock if the lock is not immediately
988: ** available. The WAL subsystem issues this signal during rare
989: ** circumstances in order to fix a problem with priority inversion.
990: ** Applications should <em>not</em> use this file-control.
991: **
992: ** <li>[[SQLITE_FCNTL_ZIPVFS]]
993: ** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other
994: ** VFS should return SQLITE_NOTFOUND for this opcode.
995: **
996: ** <li>[[SQLITE_FCNTL_RBU]]
997: ** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by
998: ** the RBU extension only. All other VFS should return SQLITE_NOTFOUND for
999: ** this opcode.
1000: ** </ul>
1001: */
1002: #define SQLITE_FCNTL_LOCKSTATE 1
1003: #define SQLITE_FCNTL_GET_LOCKPROXYFILE 2
1004: #define SQLITE_FCNTL_SET_LOCKPROXYFILE 3
1005: #define SQLITE_FCNTL_LAST_ERRNO 4
1006: #define SQLITE_FCNTL_SIZE_HINT 5
1007: #define SQLITE_FCNTL_CHUNK_SIZE 6
1008: #define SQLITE_FCNTL_FILE_POINTER 7
1009: #define SQLITE_FCNTL_SYNC_OMITTED 8
1010: #define SQLITE_FCNTL_WIN32_AV_RETRY 9
1011: #define SQLITE_FCNTL_PERSIST_WAL 10
1012: #define SQLITE_FCNTL_OVERWRITE 11
1013: #define SQLITE_FCNTL_VFSNAME 12
1014: #define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13
1015: #define SQLITE_FCNTL_PRAGMA 14
1016: #define SQLITE_FCNTL_BUSYHANDLER 15
1017: #define SQLITE_FCNTL_TEMPFILENAME 16
1018: #define SQLITE_FCNTL_MMAP_SIZE 18
1019: #define SQLITE_FCNTL_TRACE 19
1020: #define SQLITE_FCNTL_HAS_MOVED 20
1021: #define SQLITE_FCNTL_SYNC 21
1022: #define SQLITE_FCNTL_COMMIT_PHASETWO 22
1023: #define SQLITE_FCNTL_WIN32_SET_HANDLE 23
1024: #define SQLITE_FCNTL_WAL_BLOCK 24
1025: #define SQLITE_FCNTL_ZIPVFS 25
1026: #define SQLITE_FCNTL_RBU 26
1027: #define SQLITE_FCNTL_VFS_POINTER 27
1028: #define SQLITE_FCNTL_JOURNAL_POINTER 28
1029:
1030: /* deprecated names */
1031: #define SQLITE_GET_LOCKPROXYFILE SQLITE_FCNTL_GET_LOCKPROXYFILE
1032: #define SQLITE_SET_LOCKPROXYFILE SQLITE_FCNTL_SET_LOCKPROXYFILE
1033: #define SQLITE_LAST_ERRNO SQLITE_FCNTL_LAST_ERRNO
1034:
1035:
1036: /*
1037: ** CAPI3REF: Mutex Handle
1038: **
1039: ** The mutex module within SQLite defines [sqlite3_mutex] to be an
1040: ** abstract type for a mutex object. The SQLite core never looks
1041: ** at the internal representation of an [sqlite3_mutex]. It only
1042: ** deals with pointers to the [sqlite3_mutex] object.
1043: **
1044: ** Mutexes are created using [sqlite3_mutex_alloc()].
1045: */
1046: typedef struct sqlite3_mutex sqlite3_mutex;
1047:
1048: /*
1049: ** CAPI3REF: Loadable Extension Thunk
1050: **
1051: ** A pointer to the opaque sqlite3_api_routines structure is passed as
1052: ** the third parameter to entry points of [loadable extensions]. This
1053: ** structure must be typedefed in order to work around compiler warnings
1054: ** on some platforms.
1055: */
1056: typedef struct sqlite3_api_routines sqlite3_api_routines;
1057:
1058: /*
1059: ** CAPI3REF: OS Interface Object
1060: **
1061: ** An instance of the sqlite3_vfs object defines the interface between
1062: ** the SQLite core and the underlying operating system. The "vfs"
1063: ** in the name of the object stands for "virtual file system". See
1064: ** the [VFS | VFS documentation] for further information.
1065: **
1066: ** The value of the iVersion field is initially 1 but may be larger in
1067: ** future versions of SQLite. Additional fields may be appended to this
1068: ** object when the iVersion value is increased. Note that the structure
1069: ** of the sqlite3_vfs object changes in the transaction between
1070: ** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not
1071: ** modified.
1072: **
1073: ** The szOsFile field is the size of the subclassed [sqlite3_file]
1074: ** structure used by this VFS. mxPathname is the maximum length of
1075: ** a pathname in this VFS.
1076: **
1077: ** Registered sqlite3_vfs objects are kept on a linked list formed by
1078: ** the pNext pointer. The [sqlite3_vfs_register()]
1079: ** and [sqlite3_vfs_unregister()] interfaces manage this list
1080: ** in a thread-safe way. The [sqlite3_vfs_find()] interface
1081: ** searches the list. Neither the application code nor the VFS
1082: ** implementation should use the pNext pointer.
1083: **
1084: ** The pNext field is the only field in the sqlite3_vfs
1085: ** structure that SQLite will ever modify. SQLite will only access
1086: ** or modify this field while holding a particular static mutex.
1087: ** The application should never modify anything within the sqlite3_vfs
1088: ** object once the object has been registered.
1089: **
1090: ** The zName field holds the name of the VFS module. The name must
1091: ** be unique across all VFS modules.
1092: **
1093: ** [[sqlite3_vfs.xOpen]]
1094: ** ^SQLite guarantees that the zFilename parameter to xOpen
1095: ** is either a NULL pointer or string obtained
1096: ** from xFullPathname() with an optional suffix added.
1097: ** ^If a suffix is added to the zFilename parameter, it will
1098: ** consist of a single "-" character followed by no more than
1099: ** 11 alphanumeric and/or "-" characters.
1100: ** ^SQLite further guarantees that
1101: ** the string will be valid and unchanged until xClose() is
1102: ** called. Because of the previous sentence,
1103: ** the [sqlite3_file] can safely store a pointer to the
1104: ** filename if it needs to remember the filename for some reason.
1105: ** If the zFilename parameter to xOpen is a NULL pointer then xOpen
1106: ** must invent its own temporary name for the file. ^Whenever the
1107: ** xFilename parameter is NULL it will also be the case that the
1108: ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
1109: **
1110: ** The flags argument to xOpen() includes all bits set in
1111: ** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()]
1112: ** or [sqlite3_open16()] is used, then flags includes at least
1113: ** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE].
1114: ** If xOpen() opens a file read-only then it sets *pOutFlags to
1115: ** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set.
1116: **
1117: ** ^(SQLite will also add one of the following flags to the xOpen()
1118: ** call, depending on the object being opened:
1119: **
1120: ** <ul>
1121: ** <li> [SQLITE_OPEN_MAIN_DB]
1122: ** <li> [SQLITE_OPEN_MAIN_JOURNAL]
1123: ** <li> [SQLITE_OPEN_TEMP_DB]
1124: ** <li> [SQLITE_OPEN_TEMP_JOURNAL]
1125: ** <li> [SQLITE_OPEN_TRANSIENT_DB]
1126: ** <li> [SQLITE_OPEN_SUBJOURNAL]
1127: ** <li> [SQLITE_OPEN_MASTER_JOURNAL]
1128: ** <li> [SQLITE_OPEN_WAL]
1129: ** </ul>)^
1130: **
1131: ** The file I/O implementation can use the object type flags to
1132: ** change the way it deals with files. For example, an application
1133: ** that does not care about crash recovery or rollback might make
1134: ** the open of a journal file a no-op. Writes to this journal would
1135: ** also be no-ops, and any attempt to read the journal would return
1136: ** SQLITE_IOERR. Or the implementation might recognize that a database
1137: ** file will be doing page-aligned sector reads and writes in a random
1138: ** order and set up its I/O subsystem accordingly.
1139: **
1140: ** SQLite might also add one of the following flags to the xOpen method:
1141: **
1142: ** <ul>
1143: ** <li> [SQLITE_OPEN_DELETEONCLOSE]
1144: ** <li> [SQLITE_OPEN_EXCLUSIVE]
1145: ** </ul>
1146: **
1147: ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
1148: ** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE]
1149: ** will be set for TEMP databases and their journals, transient
1150: ** databases, and subjournals.
1151: **
1152: ** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
1153: ** with the [SQLITE_OPEN_CREATE] flag, which are both directly
1154: ** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
1155: ** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
1156: ** SQLITE_OPEN_CREATE, is used to indicate that file should always
1157: ** be created, and that it is an error if it already exists.
1158: ** It is <i>not</i> used to indicate the file should be opened
1159: ** for exclusive access.
1160: **
1161: ** ^At least szOsFile bytes of memory are allocated by SQLite
1162: ** to hold the [sqlite3_file] structure passed as the third
1163: ** argument to xOpen. The xOpen method does not have to
1164: ** allocate the structure; it should just fill it in. Note that
1165: ** the xOpen method must set the sqlite3_file.pMethods to either
1166: ** a valid [sqlite3_io_methods] object or to NULL. xOpen must do
1167: ** this even if the open fails. SQLite expects that the sqlite3_file.pMethods
1168: ** element will be valid after xOpen returns regardless of the success
1169: ** or failure of the xOpen call.
1170: **
1171: ** [[sqlite3_vfs.xAccess]]
1172: ** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
1173: ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
1174: ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
1175: ** to test whether a file is at least readable. The file can be a
1176: ** directory.
1177: **
1178: ** ^SQLite will always allocate at least mxPathname+1 bytes for the
1179: ** output buffer xFullPathname. The exact size of the output buffer
1180: ** is also passed as a parameter to both methods. If the output buffer
1181: ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
1182: ** handled as a fatal error by SQLite, vfs implementations should endeavor
1183: ** to prevent this by setting mxPathname to a sufficiently large value.
1184: **
1185: ** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
1186: ** interfaces are not strictly a part of the filesystem, but they are
1187: ** included in the VFS structure for completeness.
1188: ** The xRandomness() function attempts to return nBytes bytes
1189: ** of good-quality randomness into zOut. The return value is
1190: ** the actual number of bytes of randomness obtained.
1191: ** The xSleep() method causes the calling thread to sleep for at
1192: ** least the number of microseconds given. ^The xCurrentTime()
1193: ** method returns a Julian Day Number for the current date and time as
1194: ** a floating point value.
1195: ** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
1196: ** Day Number multiplied by 86400000 (the number of milliseconds in
1197: ** a 24-hour day).
1198: ** ^SQLite will use the xCurrentTimeInt64() method to get the current
1199: ** date and time if that method is available (if iVersion is 2 or
1200: ** greater and the function pointer is not NULL) and will fall back
1201: ** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
1202: **
1203: ** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
1204: ** are not used by the SQLite core. These optional interfaces are provided
1205: ** by some VFSes to facilitate testing of the VFS code. By overriding
1206: ** system calls with functions under its control, a test program can
1207: ** simulate faults and error conditions that would otherwise be difficult
1208: ** or impossible to induce. The set of system calls that can be overridden
1209: ** varies from one VFS to another, and from one version of the same VFS to the
1210: ** next. Applications that use these interfaces must be prepared for any
1211: ** or all of these interfaces to be NULL or for their behavior to change
1212: ** from one release to the next. Applications must not attempt to access
1213: ** any of these methods if the iVersion of the VFS is less than 3.
1214: */
1215: typedef struct sqlite3_vfs sqlite3_vfs;
1216: typedef void (*sqlite3_syscall_ptr)(void);
1217: struct sqlite3_vfs {
1218: int iVersion; /* Structure version number (currently 3) */
1219: int szOsFile; /* Size of subclassed sqlite3_file */
1220: int mxPathname; /* Maximum file pathname length */
1221: sqlite3_vfs *pNext; /* Next registered VFS */
1222: const char *zName; /* Name of this virtual file system */
1223: void *pAppData; /* Pointer to application-specific data */
1224: int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
1225: int flags, int *pOutFlags);
1226: int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
1227: int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
1228: int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
1229: void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
1230: void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
1231: void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
1232: void (*xDlClose)(sqlite3_vfs*, void*);
1233: int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
1234: int (*xSleep)(sqlite3_vfs*, int microseconds);
1235: int (*xCurrentTime)(sqlite3_vfs*, double*);
1236: int (*xGetLastError)(sqlite3_vfs*, int, char *);
1237: /*
1238: ** The methods above are in version 1 of the sqlite_vfs object
1239: ** definition. Those that follow are added in version 2 or later
1240: */
1241: int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
1242: /*
1243: ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
1244: ** Those below are for version 3 and greater.
1245: */
1246: int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
1247: sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
1248: const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
1249: /*
1250: ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
1251: ** New fields may be appended in future versions. The iVersion
1252: ** value will increment whenever this happens.
1253: */
1254: };
1255:
1256: /*
1257: ** CAPI3REF: Flags for the xAccess VFS method
1258: **
1259: ** These integer constants can be used as the third parameter to
1260: ** the xAccess method of an [sqlite3_vfs] object. They determine
1261: ** what kind of permissions the xAccess method is looking for.
1262: ** With SQLITE_ACCESS_EXISTS, the xAccess method
1263: ** simply checks whether the file exists.
1264: ** With SQLITE_ACCESS_READWRITE, the xAccess method
1265: ** checks whether the named directory is both readable and writable
1266: ** (in other words, if files can be added, removed, and renamed within
1267: ** the directory).
1268: ** The SQLITE_ACCESS_READWRITE constant is currently used only by the
1269: ** [temp_store_directory pragma], though this could change in a future
1270: ** release of SQLite.
1271: ** With SQLITE_ACCESS_READ, the xAccess method
1272: ** checks whether the file is readable. The SQLITE_ACCESS_READ constant is
1273: ** currently unused, though it might be used in a future release of
1274: ** SQLite.
1275: */
1276: #define SQLITE_ACCESS_EXISTS 0
1277: #define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */
1278: #define SQLITE_ACCESS_READ 2 /* Unused */
1279:
1280: /*
1281: ** CAPI3REF: Flags for the xShmLock VFS method
1282: **
1283: ** These integer constants define the various locking operations
1284: ** allowed by the xShmLock method of [sqlite3_io_methods]. The
1285: ** following are the only legal combinations of flags to the
1286: ** xShmLock method:
1287: **
1288: ** <ul>
1289: ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
1290: ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
1291: ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
1292: ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
1293: ** </ul>
1294: **
1295: ** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
1296: ** was given on the corresponding lock.
1297: **
1298: ** The xShmLock method can transition between unlocked and SHARED or
1299: ** between unlocked and EXCLUSIVE. It cannot transition between SHARED
1300: ** and EXCLUSIVE.
1301: */
1302: #define SQLITE_SHM_UNLOCK 1
1303: #define SQLITE_SHM_LOCK 2
1304: #define SQLITE_SHM_SHARED 4
1305: #define SQLITE_SHM_EXCLUSIVE 8
1306:
1307: /*
1308: ** CAPI3REF: Maximum xShmLock index
1309: **
1310: ** The xShmLock method on [sqlite3_io_methods] may use values
1311: ** between 0 and this upper bound as its "offset" argument.
1312: ** The SQLite core will never attempt to acquire or release a
1313: ** lock outside of this range
1314: */
1315: #define SQLITE_SHM_NLOCK 8
1316:
1317:
1318: /*
1319: ** CAPI3REF: Initialize The SQLite Library
1320: **
1321: ** ^The sqlite3_initialize() routine initializes the
1322: ** SQLite library. ^The sqlite3_shutdown() routine
1323: ** deallocates any resources that were allocated by sqlite3_initialize().
1324: ** These routines are designed to aid in process initialization and
1325: ** shutdown on embedded systems. Workstation applications using
1326: ** SQLite normally do not need to invoke either of these routines.
1327: **
1328: ** A call to sqlite3_initialize() is an "effective" call if it is
1329: ** the first time sqlite3_initialize() is invoked during the lifetime of
1330: ** the process, or if it is the first time sqlite3_initialize() is invoked
1331: ** following a call to sqlite3_shutdown(). ^(Only an effective call
1332: ** of sqlite3_initialize() does any initialization. All other calls
1333: ** are harmless no-ops.)^
1334: **
1335: ** A call to sqlite3_shutdown() is an "effective" call if it is the first
1336: ** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only
1337: ** an effective call to sqlite3_shutdown() does any deinitialization.
1338: ** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
1339: **
1340: ** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
1341: ** is not. The sqlite3_shutdown() interface must only be called from a
1342: ** single thread. All open [database connections] must be closed and all
1343: ** other SQLite resources must be deallocated prior to invoking
1344: ** sqlite3_shutdown().
1345: **
1346: ** Among other things, ^sqlite3_initialize() will invoke
1347: ** sqlite3_os_init(). Similarly, ^sqlite3_shutdown()
1348: ** will invoke sqlite3_os_end().
1349: **
1350: ** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
1351: ** ^If for some reason, sqlite3_initialize() is unable to initialize
1352: ** the library (perhaps it is unable to allocate a needed resource such
1353: ** as a mutex) it returns an [error code] other than [SQLITE_OK].
1354: **
1355: ** ^The sqlite3_initialize() routine is called internally by many other
1356: ** SQLite interfaces so that an application usually does not need to
1357: ** invoke sqlite3_initialize() directly. For example, [sqlite3_open()]
1358: ** calls sqlite3_initialize() so the SQLite library will be automatically
1359: ** initialized when [sqlite3_open()] is called if it has not be initialized
1360: ** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
1361: ** compile-time option, then the automatic calls to sqlite3_initialize()
1362: ** are omitted and the application must call sqlite3_initialize() directly
1363: ** prior to using any other SQLite interface. For maximum portability,
1364: ** it is recommended that applications always invoke sqlite3_initialize()
1365: ** directly prior to using any other SQLite interface. Future releases
1366: ** of SQLite may require this. In other words, the behavior exhibited
1367: ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
1368: ** default behavior in some future release of SQLite.
1369: **
1370: ** The sqlite3_os_init() routine does operating-system specific
1371: ** initialization of the SQLite library. The sqlite3_os_end()
1372: ** routine undoes the effect of sqlite3_os_init(). Typical tasks
1373: ** performed by these routines include allocation or deallocation
1374: ** of static resources, initialization of global variables,
1375: ** setting up a default [sqlite3_vfs] module, or setting up
1376: ** a default configuration using [sqlite3_config()].
1377: **
1378: ** The application should never invoke either sqlite3_os_init()
1379: ** or sqlite3_os_end() directly. The application should only invoke
1380: ** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init()
1381: ** interface is called automatically by sqlite3_initialize() and
1382: ** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate
1383: ** implementations for sqlite3_os_init() and sqlite3_os_end()
1384: ** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
1385: ** When [custom builds | built for other platforms]
1386: ** (using the [SQLITE_OS_OTHER=1] compile-time
1387: ** option) the application must supply a suitable implementation for
1388: ** sqlite3_os_init() and sqlite3_os_end(). An application-supplied
1389: ** implementation of sqlite3_os_init() or sqlite3_os_end()
1390: ** must return [SQLITE_OK] on success and some other [error code] upon
1391: ** failure.
1392: */
1393: SQLITE_API int sqlite3_initialize(void);
1394: SQLITE_API int sqlite3_shutdown(void);
1395: SQLITE_API int sqlite3_os_init(void);
1396: SQLITE_API int sqlite3_os_end(void);
1397:
1398: /*
1399: ** CAPI3REF: Configuring The SQLite Library
1400: **
1401: ** The sqlite3_config() interface is used to make global configuration
1402: ** changes to SQLite in order to tune SQLite to the specific needs of
1403: ** the application. The default configuration is recommended for most
1404: ** applications and so this routine is usually not necessary. It is
1405: ** provided to support rare applications with unusual needs.
1406: **
1407: ** <b>The sqlite3_config() interface is not threadsafe. The application
1408: ** must ensure that no other SQLite interfaces are invoked by other
1409: ** threads while sqlite3_config() is running.</b>
1410: **
1411: ** The sqlite3_config() interface
1412: ** may only be invoked prior to library initialization using
1413: ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
1414: ** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
1415: ** [sqlite3_shutdown()] then it will return SQLITE_MISUSE.
1416: ** Note, however, that ^sqlite3_config() can be called as part of the
1417: ** implementation of an application-defined [sqlite3_os_init()].
1418: **
1419: ** The first argument to sqlite3_config() is an integer
1420: ** [configuration option] that determines
1421: ** what property of SQLite is to be configured. Subsequent arguments
1422: ** vary depending on the [configuration option]
1423: ** in the first argument.
1424: **
1425: ** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
1426: ** ^If the option is unknown or SQLite is unable to set the option
1427: ** then this routine returns a non-zero [error code].
1428: */
1429: SQLITE_API int sqlite3_config(int, ...);
1430:
1431: /*
1432: ** CAPI3REF: Configure database connections
1433: ** METHOD: sqlite3
1434: **
1435: ** The sqlite3_db_config() interface is used to make configuration
1436: ** changes to a [database connection]. The interface is similar to
1437: ** [sqlite3_config()] except that the changes apply to a single
1438: ** [database connection] (specified in the first argument).
1439: **
1440: ** The second argument to sqlite3_db_config(D,V,...) is the
1441: ** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code
1442: ** that indicates what aspect of the [database connection] is being configured.
1443: ** Subsequent arguments vary depending on the configuration verb.
1444: **
1445: ** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
1446: ** the call is considered successful.
1447: */
1448: SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...);
1449:
1450: /*
1451: ** CAPI3REF: Memory Allocation Routines
1452: **
1453: ** An instance of this object defines the interface between SQLite
1454: ** and low-level memory allocation routines.
1455: **
1456: ** This object is used in only one place in the SQLite interface.
1457: ** A pointer to an instance of this object is the argument to
1458: ** [sqlite3_config()] when the configuration option is
1459: ** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].
1460: ** By creating an instance of this object
1461: ** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
1462: ** during configuration, an application can specify an alternative
1463: ** memory allocation subsystem for SQLite to use for all of its
1464: ** dynamic memory needs.
1465: **
1466: ** Note that SQLite comes with several [built-in memory allocators]
1467: ** that are perfectly adequate for the overwhelming majority of applications
1468: ** and that this object is only useful to a tiny minority of applications
1469: ** with specialized memory allocation requirements. This object is
1470: ** also used during testing of SQLite in order to specify an alternative
1471: ** memory allocator that simulates memory out-of-memory conditions in
1472: ** order to verify that SQLite recovers gracefully from such
1473: ** conditions.
1474: **
1475: ** The xMalloc, xRealloc, and xFree methods must work like the
1476: ** malloc(), realloc() and free() functions from the standard C library.
1477: ** ^SQLite guarantees that the second argument to
1478: ** xRealloc is always a value returned by a prior call to xRoundup.
1479: **
1480: ** xSize should return the allocated size of a memory allocation
1481: ** previously obtained from xMalloc or xRealloc. The allocated size
1482: ** is always at least as big as the requested size but may be larger.
1483: **
1484: ** The xRoundup method returns what would be the allocated size of
1485: ** a memory allocation given a particular requested size. Most memory
1486: ** allocators round up memory allocations at least to the next multiple
1487: ** of 8. Some allocators round up to a larger multiple or to a power of 2.
1488: ** Every memory allocation request coming in through [sqlite3_malloc()]
1489: ** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0,
1490: ** that causes the corresponding memory allocation to fail.
1491: **
1492: ** The xInit method initializes the memory allocator. For example,
1493: ** it might allocate any require mutexes or initialize internal data
1494: ** structures. The xShutdown method is invoked (indirectly) by
1495: ** [sqlite3_shutdown()] and should deallocate any resources acquired
1496: ** by xInit. The pAppData pointer is used as the only parameter to
1497: ** xInit and xShutdown.
1498: **
1499: ** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes
1500: ** the xInit method, so the xInit method need not be threadsafe. The
1501: ** xShutdown method is only called from [sqlite3_shutdown()] so it does
1502: ** not need to be threadsafe either. For all other methods, SQLite
1503: ** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
1504: ** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
1505: ** it is by default) and so the methods are automatically serialized.
1506: ** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
1507: ** methods must be threadsafe or else make their own arrangements for
1508: ** serialization.
1509: **
1510: ** SQLite will never invoke xInit() more than once without an intervening
1511: ** call to xShutdown().
1512: */
1513: typedef struct sqlite3_mem_methods sqlite3_mem_methods;
1514: struct sqlite3_mem_methods {
1515: void *(*xMalloc)(int); /* Memory allocation function */
1516: void (*xFree)(void*); /* Free a prior allocation */
1517: void *(*xRealloc)(void*,int); /* Resize an allocation */
1518: int (*xSize)(void*); /* Return the size of an allocation */
1519: int (*xRoundup)(int); /* Round up request size to allocation size */
1520: int (*xInit)(void*); /* Initialize the memory allocator */
1521: void (*xShutdown)(void*); /* Deinitialize the memory allocator */
1522: void *pAppData; /* Argument to xInit() and xShutdown() */
1523: };
1524:
1525: /*
1526: ** CAPI3REF: Configuration Options
1527: ** KEYWORDS: {configuration option}
1528: **
1529: ** These constants are the available integer configuration options that
1530: ** can be passed as the first argument to the [sqlite3_config()] interface.
1531: **
1532: ** New configuration options may be added in future releases of SQLite.
1533: ** Existing configuration options might be discontinued. Applications
1534: ** should check the return code from [sqlite3_config()] to make sure that
1535: ** the call worked. The [sqlite3_config()] interface will return a
1536: ** non-zero [error code] if a discontinued or unsupported configuration option
1537: ** is invoked.
1538: **
1539: ** <dl>
1540: ** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
1541: ** <dd>There are no arguments to this option. ^This option sets the
1542: ** [threading mode] to Single-thread. In other words, it disables
1543: ** all mutexing and puts SQLite into a mode where it can only be used
1544: ** by a single thread. ^If SQLite is compiled with
1545: ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1546: ** it is not possible to change the [threading mode] from its default
1547: ** value of Single-thread and so [sqlite3_config()] will return
1548: ** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
1549: ** configuration option.</dd>
1550: **
1551: ** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt>
1552: ** <dd>There are no arguments to this option. ^This option sets the
1553: ** [threading mode] to Multi-thread. In other words, it disables
1554: ** mutexing on [database connection] and [prepared statement] objects.
1555: ** The application is responsible for serializing access to
1556: ** [database connections] and [prepared statements]. But other mutexes
1557: ** are enabled so that SQLite will be safe to use in a multi-threaded
1558: ** environment as long as no two threads attempt to use the same
1559: ** [database connection] at the same time. ^If SQLite is compiled with
1560: ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1561: ** it is not possible to set the Multi-thread [threading mode] and
1562: ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1563: ** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
1564: **
1565: ** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt>
1566: ** <dd>There are no arguments to this option. ^This option sets the
1567: ** [threading mode] to Serialized. In other words, this option enables
1568: ** all mutexes including the recursive
1569: ** mutexes on [database connection] and [prepared statement] objects.
1570: ** In this mode (which is the default when SQLite is compiled with
1571: ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
1572: ** to [database connections] and [prepared statements] so that the
1573: ** application is free to use the same [database connection] or the
1574: ** same [prepared statement] in different threads at the same time.
1575: ** ^If SQLite is compiled with
1576: ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1577: ** it is not possible to set the Serialized [threading mode] and
1578: ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1579: ** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
1580: **
1581: ** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt>
1582: ** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is
1583: ** a pointer to an instance of the [sqlite3_mem_methods] structure.
1584: ** The argument specifies
1585: ** alternative low-level memory allocation routines to be used in place of
1586: ** the memory allocation routines built into SQLite.)^ ^SQLite makes
1587: ** its own private copy of the content of the [sqlite3_mem_methods] structure
1588: ** before the [sqlite3_config()] call returns.</dd>
1589: **
1590: ** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt>
1591: ** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which
1592: ** is a pointer to an instance of the [sqlite3_mem_methods] structure.
1593: ** The [sqlite3_mem_methods]
1594: ** structure is filled with the currently defined memory allocation routines.)^
1595: ** This option can be used to overload the default memory allocation
1596: ** routines with a wrapper that simulations memory allocation failure or
1597: ** tracks memory usage, for example. </dd>
1598: **
1599: ** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt>
1600: ** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int,
1601: ** interpreted as a boolean, which enables or disables the collection of
1602: ** memory allocation statistics. ^(When memory allocation statistics are
1603: ** disabled, the following SQLite interfaces become non-operational:
1604: ** <ul>
1605: ** <li> [sqlite3_memory_used()]
1606: ** <li> [sqlite3_memory_highwater()]
1607: ** <li> [sqlite3_soft_heap_limit64()]
1608: ** <li> [sqlite3_status64()]
1609: ** </ul>)^
1610: ** ^Memory allocation statistics are enabled by default unless SQLite is
1611: ** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
1612: ** allocation statistics are disabled by default.
1613: ** </dd>
1614: **
1615: ** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt>
1616: ** <dd> ^The SQLITE_CONFIG_SCRATCH option specifies a static memory buffer
1617: ** that SQLite can use for scratch memory. ^(There are three arguments
1618: ** to SQLITE_CONFIG_SCRATCH: A pointer an 8-byte
1619: ** aligned memory buffer from which the scratch allocations will be
1620: ** drawn, the size of each scratch allocation (sz),
1621: ** and the maximum number of scratch allocations (N).)^
1622: ** The first argument must be a pointer to an 8-byte aligned buffer
1623: ** of at least sz*N bytes of memory.
1624: ** ^SQLite will not use more than one scratch buffers per thread.
1625: ** ^SQLite will never request a scratch buffer that is more than 6
1626: ** times the database page size.
1627: ** ^If SQLite needs needs additional
1628: ** scratch memory beyond what is provided by this configuration option, then
1629: ** [sqlite3_malloc()] will be used to obtain the memory needed.<p>
1630: ** ^When the application provides any amount of scratch memory using
1631: ** SQLITE_CONFIG_SCRATCH, SQLite avoids unnecessary large
1632: ** [sqlite3_malloc|heap allocations].
1633: ** This can help [Robson proof|prevent memory allocation failures] due to heap
1634: ** fragmentation in low-memory embedded systems.
1635: ** </dd>
1636: **
1637: ** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>
1638: ** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool
1639: ** that SQLite can use for the database page cache with the default page
1640: ** cache implementation.
1641: ** This configuration option is a no-op if an application-define page
1642: ** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2].
1643: ** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to
1644: ** 8-byte aligned memory (pMem), the size of each page cache line (sz),
1645: ** and the number of cache lines (N).
1646: ** The sz argument should be the size of the largest database page
1647: ** (a power of two between 512 and 65536) plus some extra bytes for each
1648: ** page header. ^The number of extra bytes needed by the page header
1649: ** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ].
1650: ** ^It is harmless, apart from the wasted memory,
1651: ** for the sz parameter to be larger than necessary. The pMem
1652: ** argument must be either a NULL pointer or a pointer to an 8-byte
1653: ** aligned block of memory of at least sz*N bytes, otherwise
1654: ** subsequent behavior is undefined.
1655: ** ^When pMem is not NULL, SQLite will strive to use the memory provided
1656: ** to satisfy page cache needs, falling back to [sqlite3_malloc()] if
1657: ** a page cache line is larger than sz bytes or if all of the pMem buffer
1658: ** is exhausted.
1659: ** ^If pMem is NULL and N is non-zero, then each database connection
1660: ** does an initial bulk allocation for page cache memory
1661: ** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or
1662: ** of -1024*N bytes if N is negative, . ^If additional
1663: ** page cache memory is needed beyond what is provided by the initial
1664: ** allocation, then SQLite goes to [sqlite3_malloc()] separately for each
1665: ** additional cache line. </dd>
1666: **
1667: ** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt>
1668: ** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer
1669: ** that SQLite will use for all of its dynamic memory allocation needs
1670: ** beyond those provided for by [SQLITE_CONFIG_SCRATCH] and
1671: ** [SQLITE_CONFIG_PAGECACHE].
1672: ** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled
1673: ** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns
1674: ** [SQLITE_ERROR] if invoked otherwise.
1675: ** ^There are three arguments to SQLITE_CONFIG_HEAP:
1676: ** An 8-byte aligned pointer to the memory,
1677: ** the number of bytes in the memory buffer, and the minimum allocation size.
1678: ** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
1679: ** to using its default memory allocator (the system malloc() implementation),
1680: ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the
1681: ** memory pointer is not NULL then the alternative memory
1682: ** allocator is engaged to handle all of SQLites memory allocation needs.
1683: ** The first pointer (the memory pointer) must be aligned to an 8-byte
1684: ** boundary or subsequent behavior of SQLite will be undefined.
1685: ** The minimum allocation size is capped at 2**12. Reasonable values
1686: ** for the minimum allocation size are 2**5 through 2**8.</dd>
1687: **
1688: ** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt>
1689: ** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a
1690: ** pointer to an instance of the [sqlite3_mutex_methods] structure.
1691: ** The argument specifies alternative low-level mutex routines to be used
1692: ** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of
1693: ** the content of the [sqlite3_mutex_methods] structure before the call to
1694: ** [sqlite3_config()] returns. ^If SQLite is compiled with
1695: ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1696: ** the entire mutexing subsystem is omitted from the build and hence calls to
1697: ** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
1698: ** return [SQLITE_ERROR].</dd>
1699: **
1700: ** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt>
1701: ** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which
1702: ** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The
1703: ** [sqlite3_mutex_methods]
1704: ** structure is filled with the currently defined mutex routines.)^
1705: ** This option can be used to overload the default mutex allocation
1706: ** routines with a wrapper used to track mutex usage for performance
1707: ** profiling or testing, for example. ^If SQLite is compiled with
1708: ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1709: ** the entire mutexing subsystem is omitted from the build and hence calls to
1710: ** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
1711: ** return [SQLITE_ERROR].</dd>
1712: **
1713: ** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt>
1714: ** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine
1715: ** the default size of lookaside memory on each [database connection].
1716: ** The first argument is the
1717: ** size of each lookaside buffer slot and the second is the number of
1718: ** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE
1719: ** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
1720: ** option to [sqlite3_db_config()] can be used to change the lookaside
1721: ** configuration on individual connections.)^ </dd>
1722: **
1723: ** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt>
1724: ** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is
1725: ** a pointer to an [sqlite3_pcache_methods2] object. This object specifies
1726: ** the interface to a custom page cache implementation.)^
1727: ** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd>
1728: **
1729: ** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt>
1730: ** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which
1731: ** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of
1732: ** the current page cache implementation into that object.)^ </dd>
1733: **
1734: ** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>
1735: ** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite
1736: ** global [error log].
1737: ** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
1738: ** function with a call signature of void(*)(void*,int,const char*),
1739: ** and a pointer to void. ^If the function pointer is not NULL, it is
1740: ** invoked by [sqlite3_log()] to process each logging event. ^If the
1741: ** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
1742: ** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
1743: ** passed through as the first parameter to the application-defined logger
1744: ** function whenever that function is invoked. ^The second parameter to
1745: ** the logger function is a copy of the first parameter to the corresponding
1746: ** [sqlite3_log()] call and is intended to be a [result code] or an
1747: ** [extended result code]. ^The third parameter passed to the logger is
1748: ** log message after formatting via [sqlite3_snprintf()].
1749: ** The SQLite logging interface is not reentrant; the logger function
1750: ** supplied by the application must not invoke any SQLite interface.
1751: ** In a multi-threaded application, the application-defined logger
1752: ** function must be threadsafe. </dd>
1753: **
1754: ** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI
1755: ** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int.
1756: ** If non-zero, then URI handling is globally enabled. If the parameter is zero,
1757: ** then URI handling is globally disabled.)^ ^If URI handling is globally
1758: ** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()],
1759: ** [sqlite3_open16()] or
1760: ** specified as part of [ATTACH] commands are interpreted as URIs, regardless
1761: ** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
1762: ** connection is opened. ^If it is globally disabled, filenames are
1763: ** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
1764: ** database connection is opened. ^(By default, URI handling is globally
1765: ** disabled. The default value may be changed by compiling with the
1766: ** [SQLITE_USE_URI] symbol defined.)^
1767: **
1768: ** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN
1769: ** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer
1770: ** argument which is interpreted as a boolean in order to enable or disable
1771: ** the use of covering indices for full table scans in the query optimizer.
1772: ** ^The default setting is determined
1773: ** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on"
1774: ** if that compile-time option is omitted.
1775: ** The ability to disable the use of covering indices for full table scans
1776: ** is because some incorrectly coded legacy applications might malfunction
1777: ** when the optimization is enabled. Providing the ability to
1778: ** disable the optimization allows the older, buggy application code to work
1779: ** without change even with newer versions of SQLite.
1780: **
1781: ** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]]
1782: ** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE
1783: ** <dd> These options are obsolete and should not be used by new code.
1784: ** They are retained for backwards compatibility but are now no-ops.
1785: ** </dd>
1786: **
1787: ** [[SQLITE_CONFIG_SQLLOG]]
1788: ** <dt>SQLITE_CONFIG_SQLLOG
1789: ** <dd>This option is only available if sqlite is compiled with the
1790: ** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should
1791: ** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int).
1792: ** The second should be of type (void*). The callback is invoked by the library
1793: ** in three separate circumstances, identified by the value passed as the
1794: ** fourth parameter. If the fourth parameter is 0, then the database connection
1795: ** passed as the second argument has just been opened. The third argument
1796: ** points to a buffer containing the name of the main database file. If the
1797: ** fourth parameter is 1, then the SQL statement that the third parameter
1798: ** points to has just been executed. Or, if the fourth parameter is 2, then
1799: ** the connection being passed as the second parameter is being closed. The
1800: ** third parameter is passed NULL In this case. An example of using this
1801: ** configuration option can be seen in the "test_sqllog.c" source file in
1802: ** the canonical SQLite source tree.</dd>
1803: **
1804: ** [[SQLITE_CONFIG_MMAP_SIZE]]
1805: ** <dt>SQLITE_CONFIG_MMAP_SIZE
1806: ** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values
1807: ** that are the default mmap size limit (the default setting for
1808: ** [PRAGMA mmap_size]) and the maximum allowed mmap size limit.
1809: ** ^The default setting can be overridden by each database connection using
1810: ** either the [PRAGMA mmap_size] command, or by using the
1811: ** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size
1812: ** will be silently truncated if necessary so that it does not exceed the
1813: ** compile-time maximum mmap size set by the
1814: ** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^
1815: ** ^If either argument to this option is negative, then that argument is
1816: ** changed to its compile-time default.
1817: **
1818: ** [[SQLITE_CONFIG_WIN32_HEAPSIZE]]
1819: ** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE
1820: ** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is
1821: ** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro
1822: ** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value
1823: ** that specifies the maximum size of the created heap.
1824: **
1825: ** [[SQLITE_CONFIG_PCACHE_HDRSZ]]
1826: ** <dt>SQLITE_CONFIG_PCACHE_HDRSZ
1827: ** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which
1828: ** is a pointer to an integer and writes into that integer the number of extra
1829: ** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE].
1830: ** The amount of extra space required can change depending on the compiler,
1831: ** target platform, and SQLite version.
1832: **
1833: ** [[SQLITE_CONFIG_PMASZ]]
1834: ** <dt>SQLITE_CONFIG_PMASZ
1835: ** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which
1836: ** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded
1837: ** sorter to that integer. The default minimum PMA Size is set by the
1838: ** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched
1839: ** to help with sort operations when multithreaded sorting
1840: ** is enabled (using the [PRAGMA threads] command) and the amount of content
1841: ** to be sorted exceeds the page size times the minimum of the
1842: ** [PRAGMA cache_size] setting and this value.
1843: **
1844: ** [[SQLITE_CONFIG_STMTJRNL_SPILL]]
1845: ** <dt>SQLITE_CONFIG_STMTJRNL_SPILL
1846: ** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which
1847: ** becomes the [statement journal] spill-to-disk threshold.
1848: ** [Statement journals] are held in memory until their size (in bytes)
1849: ** exceeds this threshold, at which point they are written to disk.
1850: ** Or if the threshold is -1, statement journals are always held
1851: ** exclusively in memory.
1852: ** Since many statement journals never become large, setting the spill
1853: ** threshold to a value such as 64KiB can greatly reduce the amount of
1854: ** I/O required to support statement rollback.
1855: ** The default value for this setting is controlled by the
1856: ** [SQLITE_STMTJRNL_SPILL] compile-time option.
1857: ** </dl>
1858: */
1859: #define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */
1860: #define SQLITE_CONFIG_MULTITHREAD 2 /* nil */
1861: #define SQLITE_CONFIG_SERIALIZED 3 /* nil */
1862: #define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */
1863: #define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */
1864: #define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */
1865: #define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */
1866: #define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */
1867: #define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */
1868: #define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */
1869: #define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */
1870: /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */
1871: #define SQLITE_CONFIG_LOOKASIDE 13 /* int int */
1872: #define SQLITE_CONFIG_PCACHE 14 /* no-op */
1873: #define SQLITE_CONFIG_GETPCACHE 15 /* no-op */
1874: #define SQLITE_CONFIG_LOG 16 /* xFunc, void* */
1875: #define SQLITE_CONFIG_URI 17 /* int */
1876: #define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */
1877: #define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */
1878: #define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */
1879: #define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */
1880: #define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */
1881: #define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */
1882: #define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */
1883: #define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */
1884: #define SQLITE_CONFIG_STMTJRNL_SPILL 26 /* int nByte */
1885:
1886: /*
1887: ** CAPI3REF: Database Connection Configuration Options
1888: **
1889: ** These constants are the available integer configuration options that
1890: ** can be passed as the second argument to the [sqlite3_db_config()] interface.
1891: **
1892: ** New configuration options may be added in future releases of SQLite.
1893: ** Existing configuration options might be discontinued. Applications
1894: ** should check the return code from [sqlite3_db_config()] to make sure that
1895: ** the call worked. ^The [sqlite3_db_config()] interface will return a
1896: ** non-zero [error code] if a discontinued or unsupported configuration option
1897: ** is invoked.
1898: **
1899: ** <dl>
1900: ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
1901: ** <dd> ^This option takes three additional arguments that determine the
1902: ** [lookaside memory allocator] configuration for the [database connection].
1903: ** ^The first argument (the third parameter to [sqlite3_db_config()] is a
1904: ** pointer to a memory buffer to use for lookaside memory.
1905: ** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
1906: ** may be NULL in which case SQLite will allocate the
1907: ** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
1908: ** size of each lookaside buffer slot. ^The third argument is the number of
1909: ** slots. The size of the buffer in the first argument must be greater than
1910: ** or equal to the product of the second and third arguments. The buffer
1911: ** must be aligned to an 8-byte boundary. ^If the second argument to
1912: ** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
1913: ** rounded down to the next smaller multiple of 8. ^(The lookaside memory
1914: ** configuration for a database connection can only be changed when that
1915: ** connection is not currently using lookaside memory, or in other words
1916: ** when the "current value" returned by
1917: ** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero.
1918: ** Any attempt to change the lookaside memory configuration when lookaside
1919: ** memory is in use leaves the configuration unchanged and returns
1920: ** [SQLITE_BUSY].)^</dd>
1921: **
1922: ** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
1923: ** <dd> ^This option is used to enable or disable the enforcement of
1924: ** [foreign key constraints]. There should be two additional arguments.
1925: ** The first argument is an integer which is 0 to disable FK enforcement,
1926: ** positive to enable FK enforcement or negative to leave FK enforcement
1927: ** unchanged. The second parameter is a pointer to an integer into which
1928: ** is written 0 or 1 to indicate whether FK enforcement is off or on
1929: ** following this call. The second parameter may be a NULL pointer, in
1930: ** which case the FK enforcement setting is not reported back. </dd>
1931: **
1932: ** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
1933: ** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
1934: ** There should be two additional arguments.
1935: ** The first argument is an integer which is 0 to disable triggers,
1936: ** positive to enable triggers or negative to leave the setting unchanged.
1937: ** The second parameter is a pointer to an integer into which
1938: ** is written 0 or 1 to indicate whether triggers are disabled or enabled
1939: ** following this call. The second parameter may be a NULL pointer, in
1940: ** which case the trigger setting is not reported back. </dd>
1941: **
1942: ** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt>
1943: ** <dd> ^This option is used to enable or disable the two-argument
1944: ** version of the [fts3_tokenizer()] function which is part of the
1945: ** [FTS3] full-text search engine extension.
1946: ** There should be two additional arguments.
1947: ** The first argument is an integer which is 0 to disable fts3_tokenizer() or
1948: ** positive to enable fts3_tokenizer() or negative to leave the setting
1949: ** unchanged.
1950: ** The second parameter is a pointer to an integer into which
1951: ** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled
1952: ** following this call. The second parameter may be a NULL pointer, in
1953: ** which case the new setting is not reported back. </dd>
1954: **
1955: ** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt>
1956: ** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()]
1957: ** interface independently of the [load_extension()] SQL function.
1958: ** The [sqlite3_enable_load_extension()] API enables or disables both the
1959: ** C-API [sqlite3_load_extension()] and the SQL function [load_extension()].
1960: ** There should be two additional arguments.
1961: ** When the first argument to this interface is 1, then only the C-API is
1962: ** enabled and the SQL function remains disabled. If the first argument to
1963: ** this interface is 0, then both the C-API and the SQL function are disabled.
1964: ** If the first argument is -1, then no changes are made to state of either the
1965: ** C-API or the SQL function.
1966: ** The second parameter is a pointer to an integer into which
1967: ** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface
1968: ** is disabled or enabled following this call. The second parameter may
1969: ** be a NULL pointer, in which case the new setting is not reported back.
1970: ** </dd>
1971: **
1972: ** </dl>
1973: */
1974: #define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */
1975: #define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */
1976: #define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */
1977: #define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */
1978: #define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */
1979:
1980:
1981: /*
1982: ** CAPI3REF: Enable Or Disable Extended Result Codes
1983: ** METHOD: sqlite3
1984: **
1985: ** ^The sqlite3_extended_result_codes() routine enables or disables the
1986: ** [extended result codes] feature of SQLite. ^The extended result
1987: ** codes are disabled by default for historical compatibility.
1988: */
1989: SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff);
1990:
1991: /*
1992: ** CAPI3REF: Last Insert Rowid
1993: ** METHOD: sqlite3
1994: **
1995: ** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables)
1996: ** has a unique 64-bit signed
1997: ** integer key called the [ROWID | "rowid"]. ^The rowid is always available
1998: ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
1999: ** names are not also used by explicitly declared columns. ^If
2000: ** the table has a column of type [INTEGER PRIMARY KEY] then that column
2001: ** is another alias for the rowid.
2002: **
2003: ** ^The sqlite3_last_insert_rowid(D) interface returns the [rowid] of the
2004: ** most recent successful [INSERT] into a rowid table or [virtual table]
2005: ** on database connection D.
2006: ** ^Inserts into [WITHOUT ROWID] tables are not recorded.
2007: ** ^If no successful [INSERT]s into rowid tables
2008: ** have ever occurred on the database connection D,
2009: ** then sqlite3_last_insert_rowid(D) returns zero.
2010: **
2011: ** ^(If an [INSERT] occurs within a trigger or within a [virtual table]
2012: ** method, then this routine will return the [rowid] of the inserted
2013: ** row as long as the trigger or virtual table method is running.
2014: ** But once the trigger or virtual table method ends, the value returned
2015: ** by this routine reverts to what it was before the trigger or virtual
2016: ** table method began.)^
2017: **
2018: ** ^An [INSERT] that fails due to a constraint violation is not a
2019: ** successful [INSERT] and does not change the value returned by this
2020: ** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
2021: ** and INSERT OR ABORT make no changes to the return value of this
2022: ** routine when their insertion fails. ^(When INSERT OR REPLACE
2023: ** encounters a constraint violation, it does not fail. The
2024: ** INSERT continues to completion after deleting rows that caused
2025: ** the constraint problem so INSERT OR REPLACE will always change
2026: ** the return value of this interface.)^
2027: **
2028: ** ^For the purposes of this routine, an [INSERT] is considered to
2029: ** be successful even if it is subsequently rolled back.
2030: **
2031: ** This function is accessible to SQL statements via the
2032: ** [last_insert_rowid() SQL function].
2033: **
2034: ** If a separate thread performs a new [INSERT] on the same
2035: ** database connection while the [sqlite3_last_insert_rowid()]
2036: ** function is running and thus changes the last insert [rowid],
2037: ** then the value returned by [sqlite3_last_insert_rowid()] is
2038: ** unpredictable and might not equal either the old or the new
2039: ** last insert [rowid].
2040: */
2041: SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
2042:
2043: /*
2044: ** CAPI3REF: Count The Number Of Rows Modified
2045: ** METHOD: sqlite3
2046: **
2047: ** ^This function returns the number of rows modified, inserted or
2048: ** deleted by the most recently completed INSERT, UPDATE or DELETE
2049: ** statement on the database connection specified by the only parameter.
2050: ** ^Executing any other type of SQL statement does not modify the value
2051: ** returned by this function.
2052: **
2053: ** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are
2054: ** considered - auxiliary changes caused by [CREATE TRIGGER | triggers],
2055: ** [foreign key actions] or [REPLACE] constraint resolution are not counted.
2056: **
2057: ** Changes to a view that are intercepted by
2058: ** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value
2059: ** returned by sqlite3_changes() immediately after an INSERT, UPDATE or
2060: ** DELETE statement run on a view is always zero. Only changes made to real
2061: ** tables are counted.
2062: **
2063: ** Things are more complicated if the sqlite3_changes() function is
2064: ** executed while a trigger program is running. This may happen if the
2065: ** program uses the [changes() SQL function], or if some other callback
2066: ** function invokes sqlite3_changes() directly. Essentially:
2067: **
2068: ** <ul>
2069: ** <li> ^(Before entering a trigger program the value returned by
2070: ** sqlite3_changes() function is saved. After the trigger program
2071: ** has finished, the original value is restored.)^
2072: **
2073: ** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE
2074: ** statement sets the value returned by sqlite3_changes()
2075: ** upon completion as normal. Of course, this value will not include
2076: ** any changes performed by sub-triggers, as the sqlite3_changes()
2077: ** value will be saved and restored after each sub-trigger has run.)^
2078: ** </ul>
2079: **
2080: ** ^This means that if the changes() SQL function (or similar) is used
2081: ** by the first INSERT, UPDATE or DELETE statement within a trigger, it
2082: ** returns the value as set when the calling statement began executing.
2083: ** ^If it is used by the second or subsequent such statement within a trigger
2084: ** program, the value returned reflects the number of rows modified by the
2085: ** previous INSERT, UPDATE or DELETE statement within the same trigger.
2086: **
2087: ** See also the [sqlite3_total_changes()] interface, the
2088: ** [count_changes pragma], and the [changes() SQL function].
2089: **
2090: ** If a separate thread makes changes on the same database connection
2091: ** while [sqlite3_changes()] is running then the value returned
2092: ** is unpredictable and not meaningful.
2093: */
2094: SQLITE_API int sqlite3_changes(sqlite3*);
2095:
2096: /*
2097: ** CAPI3REF: Total Number Of Rows Modified
2098: ** METHOD: sqlite3
2099: **
2100: ** ^This function returns the total number of rows inserted, modified or
2101: ** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed
2102: ** since the database connection was opened, including those executed as
2103: ** part of trigger programs. ^Executing any other type of SQL statement
2104: ** does not affect the value returned by sqlite3_total_changes().
2105: **
2106: ** ^Changes made as part of [foreign key actions] are included in the
2107: ** count, but those made as part of REPLACE constraint resolution are
2108: ** not. ^Changes to a view that are intercepted by INSTEAD OF triggers
2109: ** are not counted.
2110: **
2111: ** See also the [sqlite3_changes()] interface, the
2112: ** [count_changes pragma], and the [total_changes() SQL function].
2113: **
2114: ** If a separate thread makes changes on the same database connection
2115: ** while [sqlite3_total_changes()] is running then the value
2116: ** returned is unpredictable and not meaningful.
2117: */
2118: SQLITE_API int sqlite3_total_changes(sqlite3*);
2119:
2120: /*
2121: ** CAPI3REF: Interrupt A Long-Running Query
2122: ** METHOD: sqlite3
2123: **
2124: ** ^This function causes any pending database operation to abort and
2125: ** return at its earliest opportunity. This routine is typically
2126: ** called in response to a user action such as pressing "Cancel"
2127: ** or Ctrl-C where the user wants a long query operation to halt
2128: ** immediately.
2129: **
2130: ** ^It is safe to call this routine from a thread different from the
2131: ** thread that is currently running the database operation. But it
2132: ** is not safe to call this routine with a [database connection] that
2133: ** is closed or might close before sqlite3_interrupt() returns.
2134: **
2135: ** ^If an SQL operation is very nearly finished at the time when
2136: ** sqlite3_interrupt() is called, then it might not have an opportunity
2137: ** to be interrupted and might continue to completion.
2138: **
2139: ** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
2140: ** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
2141: ** that is inside an explicit transaction, then the entire transaction
2142: ** will be rolled back automatically.
2143: **
2144: ** ^The sqlite3_interrupt(D) call is in effect until all currently running
2145: ** SQL statements on [database connection] D complete. ^Any new SQL statements
2146: ** that are started after the sqlite3_interrupt() call and before the
2147: ** running statements reaches zero are interrupted as if they had been
2148: ** running prior to the sqlite3_interrupt() call. ^New SQL statements
2149: ** that are started after the running statement count reaches zero are
2150: ** not effected by the sqlite3_interrupt().
2151: ** ^A call to sqlite3_interrupt(D) that occurs when there are no running
2152: ** SQL statements is a no-op and has no effect on SQL statements
2153: ** that are started after the sqlite3_interrupt() call returns.
2154: **
2155: ** If the database connection closes while [sqlite3_interrupt()]
2156: ** is running then bad things will likely happen.
2157: */
2158: SQLITE_API void sqlite3_interrupt(sqlite3*);
2159:
2160: /*
2161: ** CAPI3REF: Determine If An SQL Statement Is Complete
2162: **
2163: ** These routines are useful during command-line input to determine if the
2164: ** currently entered text seems to form a complete SQL statement or
2165: ** if additional input is needed before sending the text into
2166: ** SQLite for parsing. ^These routines return 1 if the input string
2167: ** appears to be a complete SQL statement. ^A statement is judged to be
2168: ** complete if it ends with a semicolon token and is not a prefix of a
2169: ** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within
2170: ** string literals or quoted identifier names or comments are not
2171: ** independent tokens (they are part of the token in which they are
2172: ** embedded) and thus do not count as a statement terminator. ^Whitespace
2173: ** and comments that follow the final semicolon are ignored.
2174: **
2175: ** ^These routines return 0 if the statement is incomplete. ^If a
2176: ** memory allocation fails, then SQLITE_NOMEM is returned.
2177: **
2178: ** ^These routines do not parse the SQL statements thus
2179: ** will not detect syntactically incorrect SQL.
2180: **
2181: ** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior
2182: ** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
2183: ** automatically by sqlite3_complete16(). If that initialization fails,
2184: ** then the return value from sqlite3_complete16() will be non-zero
2185: ** regardless of whether or not the input SQL is complete.)^
2186: **
2187: ** The input to [sqlite3_complete()] must be a zero-terminated
2188: ** UTF-8 string.
2189: **
2190: ** The input to [sqlite3_complete16()] must be a zero-terminated
2191: ** UTF-16 string in native byte order.
2192: */
2193: SQLITE_API int sqlite3_complete(const char *sql);
2194: SQLITE_API int sqlite3_complete16(const void *sql);
2195:
2196: /*
2197: ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
2198: ** KEYWORDS: {busy-handler callback} {busy handler}
2199: ** METHOD: sqlite3
2200: **
2201: ** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X
2202: ** that might be invoked with argument P whenever
2203: ** an attempt is made to access a database table associated with
2204: ** [database connection] D when another thread
2205: ** or process has the table locked.
2206: ** The sqlite3_busy_handler() interface is used to implement
2207: ** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout].
2208: **
2209: ** ^If the busy callback is NULL, then [SQLITE_BUSY]
2210: ** is returned immediately upon encountering the lock. ^If the busy callback
2211: ** is not NULL, then the callback might be invoked with two arguments.
2212: **
2213: ** ^The first argument to the busy handler is a copy of the void* pointer which
2214: ** is the third argument to sqlite3_busy_handler(). ^The second argument to
2215: ** the busy handler callback is the number of times that the busy handler has
2216: ** been invoked previously for the same locking event. ^If the
2217: ** busy callback returns 0, then no additional attempts are made to
2218: ** access the database and [SQLITE_BUSY] is returned
2219: ** to the application.
2220: ** ^If the callback returns non-zero, then another attempt
2221: ** is made to access the database and the cycle repeats.
2222: **
2223: ** The presence of a busy handler does not guarantee that it will be invoked
2224: ** when there is lock contention. ^If SQLite determines that invoking the busy
2225: ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
2226: ** to the application instead of invoking the
2227: ** busy handler.
2228: ** Consider a scenario where one process is holding a read lock that
2229: ** it is trying to promote to a reserved lock and
2230: ** a second process is holding a reserved lock that it is trying
2231: ** to promote to an exclusive lock. The first process cannot proceed
2232: ** because it is blocked by the second and the second process cannot
2233: ** proceed because it is blocked by the first. If both processes
2234: ** invoke the busy handlers, neither will make any progress. Therefore,
2235: ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
2236: ** will induce the first process to release its read lock and allow
2237: ** the second process to proceed.
2238: **
2239: ** ^The default busy callback is NULL.
2240: **
2241: ** ^(There can only be a single busy handler defined for each
2242: ** [database connection]. Setting a new busy handler clears any
2243: ** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()]
2244: ** or evaluating [PRAGMA busy_timeout=N] will change the
2245: ** busy handler and thus clear any previously set busy handler.
2246: **
2247: ** The busy callback should not take any actions which modify the
2248: ** database connection that invoked the busy handler. In other words,
2249: ** the busy handler is not reentrant. Any such actions
2250: ** result in undefined behavior.
2251: **
2252: ** A busy handler must not close the database connection
2253: ** or [prepared statement] that invoked the busy handler.
2254: */
2255: SQLITE_API int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*);
2256:
2257: /*
2258: ** CAPI3REF: Set A Busy Timeout
2259: ** METHOD: sqlite3
2260: **
2261: ** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
2262: ** for a specified amount of time when a table is locked. ^The handler
2263: ** will sleep multiple times until at least "ms" milliseconds of sleeping
2264: ** have accumulated. ^After at least "ms" milliseconds of sleeping,
2265: ** the handler returns 0 which causes [sqlite3_step()] to return
2266: ** [SQLITE_BUSY].
2267: **
2268: ** ^Calling this routine with an argument less than or equal to zero
2269: ** turns off all busy handlers.
2270: **
2271: ** ^(There can only be a single busy handler for a particular
2272: ** [database connection] at any given moment. If another busy handler
2273: ** was defined (using [sqlite3_busy_handler()]) prior to calling
2274: ** this routine, that other busy handler is cleared.)^
2275: **
2276: ** See also: [PRAGMA busy_timeout]
2277: */
2278: SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms);
2279:
2280: /*
2281: ** CAPI3REF: Convenience Routines For Running Queries
2282: ** METHOD: sqlite3
2283: **
2284: ** This is a legacy interface that is preserved for backwards compatibility.
2285: ** Use of this interface is not recommended.
2286: **
2287: ** Definition: A <b>result table</b> is memory data structure created by the
2288: ** [sqlite3_get_table()] interface. A result table records the
2289: ** complete query results from one or more queries.
2290: **
2291: ** The table conceptually has a number of rows and columns. But
2292: ** these numbers are not part of the result table itself. These
2293: ** numbers are obtained separately. Let N be the number of rows
2294: ** and M be the number of columns.
2295: **
2296: ** A result table is an array of pointers to zero-terminated UTF-8 strings.
2297: ** There are (N+1)*M elements in the array. The first M pointers point
2298: ** to zero-terminated strings that contain the names of the columns.
2299: ** The remaining entries all point to query results. NULL values result
2300: ** in NULL pointers. All other values are in their UTF-8 zero-terminated
2301: ** string representation as returned by [sqlite3_column_text()].
2302: **
2303: ** A result table might consist of one or more memory allocations.
2304: ** It is not safe to pass a result table directly to [sqlite3_free()].
2305: ** A result table should be deallocated using [sqlite3_free_table()].
2306: **
2307: ** ^(As an example of the result table format, suppose a query result
2308: ** is as follows:
2309: **
2310: ** <blockquote><pre>
2311: ** Name | Age
2312: ** -----------------------
2313: ** Alice | 43
2314: ** Bob | 28
2315: ** Cindy | 21
2316: ** </pre></blockquote>
2317: **
2318: ** There are two column (M==2) and three rows (N==3). Thus the
2319: ** result table has 8 entries. Suppose the result table is stored
2320: ** in an array names azResult. Then azResult holds this content:
2321: **
2322: ** <blockquote><pre>
2323: ** azResult[0] = "Name";
2324: ** azResult[1] = "Age";
2325: ** azResult[2] = "Alice";
2326: ** azResult[3] = "43";
2327: ** azResult[4] = "Bob";
2328: ** azResult[5] = "28";
2329: ** azResult[6] = "Cindy";
2330: ** azResult[7] = "21";
2331: ** </pre></blockquote>)^
2332: **
2333: ** ^The sqlite3_get_table() function evaluates one or more
2334: ** semicolon-separated SQL statements in the zero-terminated UTF-8
2335: ** string of its 2nd parameter and returns a result table to the
2336: ** pointer given in its 3rd parameter.
2337: **
2338: ** After the application has finished with the result from sqlite3_get_table(),
2339: ** it must pass the result table pointer to sqlite3_free_table() in order to
2340: ** release the memory that was malloced. Because of the way the
2341: ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
2342: ** function must not try to call [sqlite3_free()] directly. Only
2343: ** [sqlite3_free_table()] is able to release the memory properly and safely.
2344: **
2345: ** The sqlite3_get_table() interface is implemented as a wrapper around
2346: ** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access
2347: ** to any internal data structures of SQLite. It uses only the public
2348: ** interface defined here. As a consequence, errors that occur in the
2349: ** wrapper layer outside of the internal [sqlite3_exec()] call are not
2350: ** reflected in subsequent calls to [sqlite3_errcode()] or
2351: ** [sqlite3_errmsg()].
2352: */
2353: SQLITE_API int sqlite3_get_table(
2354: sqlite3 *db, /* An open database */
2355: const char *zSql, /* SQL to be evaluated */
2356: char ***pazResult, /* Results of the query */
2357: int *pnRow, /* Number of result rows written here */
2358: int *pnColumn, /* Number of result columns written here */
2359: char **pzErrmsg /* Error msg written here */
2360: );
2361: SQLITE_API void sqlite3_free_table(char **result);
2362:
2363: /*
2364: ** CAPI3REF: Formatted String Printing Functions
2365: **
2366: ** These routines are work-alikes of the "printf()" family of functions
2367: ** from the standard C library.
2368: ** These routines understand most of the common K&R formatting options,
2369: ** plus some additional non-standard formats, detailed below.
2370: ** Note that some of the more obscure formatting options from recent
2371: ** C-library standards are omitted from this implementation.
2372: **
2373: ** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
2374: ** results into memory obtained from [sqlite3_malloc()].
2375: ** The strings returned by these two routines should be
2376: ** released by [sqlite3_free()]. ^Both routines return a
2377: ** NULL pointer if [sqlite3_malloc()] is unable to allocate enough
2378: ** memory to hold the resulting string.
2379: **
2380: ** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
2381: ** the standard C library. The result is written into the
2382: ** buffer supplied as the second parameter whose size is given by
2383: ** the first parameter. Note that the order of the
2384: ** first two parameters is reversed from snprintf().)^ This is an
2385: ** historical accident that cannot be fixed without breaking
2386: ** backwards compatibility. ^(Note also that sqlite3_snprintf()
2387: ** returns a pointer to its buffer instead of the number of
2388: ** characters actually written into the buffer.)^ We admit that
2389: ** the number of characters written would be a more useful return
2390: ** value but we cannot change the implementation of sqlite3_snprintf()
2391: ** now without breaking compatibility.
2392: **
2393: ** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
2394: ** guarantees that the buffer is always zero-terminated. ^The first
2395: ** parameter "n" is the total size of the buffer, including space for
2396: ** the zero terminator. So the longest string that can be completely
2397: ** written will be n-1 characters.
2398: **
2399: ** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
2400: **
2401: ** These routines all implement some additional formatting
2402: ** options that are useful for constructing SQL statements.
2403: ** All of the usual printf() formatting options apply. In addition, there
2404: ** is are "%q", "%Q", "%w" and "%z" options.
2405: **
2406: ** ^(The %q option works like %s in that it substitutes a nul-terminated
2407: ** string from the argument list. But %q also doubles every '\'' character.
2408: ** %q is designed for use inside a string literal.)^ By doubling each '\''
2409: ** character it escapes that character and allows it to be inserted into
2410: ** the string.
2411: **
2412: ** For example, assume the string variable zText contains text as follows:
2413: **
2414: ** <blockquote><pre>
2415: ** char *zText = "It's a happy day!";
2416: ** </pre></blockquote>
2417: **
2418: ** One can use this text in an SQL statement as follows:
2419: **
2420: ** <blockquote><pre>
2421: ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText);
2422: ** sqlite3_exec(db, zSQL, 0, 0, 0);
2423: ** sqlite3_free(zSQL);
2424: ** </pre></blockquote>
2425: **
2426: ** Because the %q format string is used, the '\'' character in zText
2427: ** is escaped and the SQL generated is as follows:
2428: **
2429: ** <blockquote><pre>
2430: ** INSERT INTO table1 VALUES('It''s a happy day!')
2431: ** </pre></blockquote>
2432: **
2433: ** This is correct. Had we used %s instead of %q, the generated SQL
2434: ** would have looked like this:
2435: **
2436: ** <blockquote><pre>
2437: ** INSERT INTO table1 VALUES('It's a happy day!');
2438: ** </pre></blockquote>
2439: **
2440: ** This second example is an SQL syntax error. As a general rule you should
2441: ** always use %q instead of %s when inserting text into a string literal.
2442: **
2443: ** ^(The %Q option works like %q except it also adds single quotes around
2444: ** the outside of the total string. Additionally, if the parameter in the
2445: ** argument list is a NULL pointer, %Q substitutes the text "NULL" (without
2446: ** single quotes).)^ So, for example, one could say:
2447: **
2448: ** <blockquote><pre>
2449: ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText);
2450: ** sqlite3_exec(db, zSQL, 0, 0, 0);
2451: ** sqlite3_free(zSQL);
2452: ** </pre></blockquote>
2453: **
2454: ** The code above will render a correct SQL statement in the zSQL
2455: ** variable even if the zText variable is a NULL pointer.
2456: **
2457: ** ^(The "%w" formatting option is like "%q" except that it expects to
2458: ** be contained within double-quotes instead of single quotes, and it
2459: ** escapes the double-quote character instead of the single-quote
2460: ** character.)^ The "%w" formatting option is intended for safely inserting
2461: ** table and column names into a constructed SQL statement.
2462: **
2463: ** ^(The "%z" formatting option works like "%s" but with the
2464: ** addition that after the string has been read and copied into
2465: ** the result, [sqlite3_free()] is called on the input string.)^
2466: */
2467: SQLITE_API char *sqlite3_mprintf(const char*,...);
2468: SQLITE_API char *sqlite3_vmprintf(const char*, va_list);
2469: SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...);
2470: SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list);
2471:
2472: /*
2473: ** CAPI3REF: Memory Allocation Subsystem
2474: **
2475: ** The SQLite core uses these three routines for all of its own
2476: ** internal memory allocation needs. "Core" in the previous sentence
2477: ** does not include operating-system specific VFS implementation. The
2478: ** Windows VFS uses native malloc() and free() for some operations.
2479: **
2480: ** ^The sqlite3_malloc() routine returns a pointer to a block
2481: ** of memory at least N bytes in length, where N is the parameter.
2482: ** ^If sqlite3_malloc() is unable to obtain sufficient free
2483: ** memory, it returns a NULL pointer. ^If the parameter N to
2484: ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
2485: ** a NULL pointer.
2486: **
2487: ** ^The sqlite3_malloc64(N) routine works just like
2488: ** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead
2489: ** of a signed 32-bit integer.
2490: **
2491: ** ^Calling sqlite3_free() with a pointer previously returned
2492: ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
2493: ** that it might be reused. ^The sqlite3_free() routine is
2494: ** a no-op if is called with a NULL pointer. Passing a NULL pointer
2495: ** to sqlite3_free() is harmless. After being freed, memory
2496: ** should neither be read nor written. Even reading previously freed
2497: ** memory might result in a segmentation fault or other severe error.
2498: ** Memory corruption, a segmentation fault, or other severe error
2499: ** might result if sqlite3_free() is called with a non-NULL pointer that
2500: ** was not obtained from sqlite3_malloc() or sqlite3_realloc().
2501: **
2502: ** ^The sqlite3_realloc(X,N) interface attempts to resize a
2503: ** prior memory allocation X to be at least N bytes.
2504: ** ^If the X parameter to sqlite3_realloc(X,N)
2505: ** is a NULL pointer then its behavior is identical to calling
2506: ** sqlite3_malloc(N).
2507: ** ^If the N parameter to sqlite3_realloc(X,N) is zero or
2508: ** negative then the behavior is exactly the same as calling
2509: ** sqlite3_free(X).
2510: ** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation
2511: ** of at least N bytes in size or NULL if insufficient memory is available.
2512: ** ^If M is the size of the prior allocation, then min(N,M) bytes
2513: ** of the prior allocation are copied into the beginning of buffer returned
2514: ** by sqlite3_realloc(X,N) and the prior allocation is freed.
2515: ** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the
2516: ** prior allocation is not freed.
2517: **
2518: ** ^The sqlite3_realloc64(X,N) interfaces works the same as
2519: ** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead
2520: ** of a 32-bit signed integer.
2521: **
2522: ** ^If X is a memory allocation previously obtained from sqlite3_malloc(),
2523: ** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then
2524: ** sqlite3_msize(X) returns the size of that memory allocation in bytes.
2525: ** ^The value returned by sqlite3_msize(X) might be larger than the number
2526: ** of bytes requested when X was allocated. ^If X is a NULL pointer then
2527: ** sqlite3_msize(X) returns zero. If X points to something that is not
2528: ** the beginning of memory allocation, or if it points to a formerly
2529: ** valid memory allocation that has now been freed, then the behavior
2530: ** of sqlite3_msize(X) is undefined and possibly harmful.
2531: **
2532: ** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(),
2533: ** sqlite3_malloc64(), and sqlite3_realloc64()
2534: ** is always aligned to at least an 8 byte boundary, or to a
2535: ** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
2536: ** option is used.
2537: **
2538: ** In SQLite version 3.5.0 and 3.5.1, it was possible to define
2539: ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in
2540: ** implementation of these routines to be omitted. That capability
2541: ** is no longer provided. Only built-in memory allocators can be used.
2542: **
2543: ** Prior to SQLite version 3.7.10, the Windows OS interface layer called
2544: ** the system malloc() and free() directly when converting
2545: ** filenames between the UTF-8 encoding used by SQLite
2546: ** and whatever filename encoding is used by the particular Windows
2547: ** installation. Memory allocation errors were detected, but
2548: ** they were reported back as [SQLITE_CANTOPEN] or
2549: ** [SQLITE_IOERR] rather than [SQLITE_NOMEM].
2550: **
2551: ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
2552: ** must be either NULL or else pointers obtained from a prior
2553: ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
2554: ** not yet been released.
2555: **
2556: ** The application must not read or write any part of
2557: ** a block of memory after it has been released using
2558: ** [sqlite3_free()] or [sqlite3_realloc()].
2559: */
2560: SQLITE_API void *sqlite3_malloc(int);
2561: SQLITE_API void *sqlite3_malloc64(sqlite3_uint64);
2562: SQLITE_API void *sqlite3_realloc(void*, int);
2563: SQLITE_API void *sqlite3_realloc64(void*, sqlite3_uint64);
2564: SQLITE_API void sqlite3_free(void*);
2565: SQLITE_API sqlite3_uint64 sqlite3_msize(void*);
2566:
2567: /*
2568: ** CAPI3REF: Memory Allocator Statistics
2569: **
2570: ** SQLite provides these two interfaces for reporting on the status
2571: ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
2572: ** routines, which form the built-in memory allocation subsystem.
2573: **
2574: ** ^The [sqlite3_memory_used()] routine returns the number of bytes
2575: ** of memory currently outstanding (malloced but not freed).
2576: ** ^The [sqlite3_memory_highwater()] routine returns the maximum
2577: ** value of [sqlite3_memory_used()] since the high-water mark
2578: ** was last reset. ^The values returned by [sqlite3_memory_used()] and
2579: ** [sqlite3_memory_highwater()] include any overhead
2580: ** added by SQLite in its implementation of [sqlite3_malloc()],
2581: ** but not overhead added by the any underlying system library
2582: ** routines that [sqlite3_malloc()] may call.
2583: **
2584: ** ^The memory high-water mark is reset to the current value of
2585: ** [sqlite3_memory_used()] if and only if the parameter to
2586: ** [sqlite3_memory_highwater()] is true. ^The value returned
2587: ** by [sqlite3_memory_highwater(1)] is the high-water mark
2588: ** prior to the reset.
2589: */
2590: SQLITE_API sqlite3_int64 sqlite3_memory_used(void);
2591: SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
2592:
2593: /*
2594: ** CAPI3REF: Pseudo-Random Number Generator
2595: **
2596: ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
2597: ** select random [ROWID | ROWIDs] when inserting new records into a table that
2598: ** already uses the largest possible [ROWID]. The PRNG is also used for
2599: ** the build-in random() and randomblob() SQL functions. This interface allows
2600: ** applications to access the same PRNG for other purposes.
2601: **
2602: ** ^A call to this routine stores N bytes of randomness into buffer P.
2603: ** ^The P parameter can be a NULL pointer.
2604: **
2605: ** ^If this routine has not been previously called or if the previous
2606: ** call had N less than one or a NULL pointer for P, then the PRNG is
2607: ** seeded using randomness obtained from the xRandomness method of
2608: ** the default [sqlite3_vfs] object.
2609: ** ^If the previous call to this routine had an N of 1 or more and a
2610: ** non-NULL P then the pseudo-randomness is generated
2611: ** internally and without recourse to the [sqlite3_vfs] xRandomness
2612: ** method.
2613: */
2614: SQLITE_API void sqlite3_randomness(int N, void *P);
2615:
2616: /*
2617: ** CAPI3REF: Compile-Time Authorization Callbacks
2618: ** METHOD: sqlite3
2619: **
2620: ** ^This routine registers an authorizer callback with a particular
2621: ** [database connection], supplied in the first argument.
2622: ** ^The authorizer callback is invoked as SQL statements are being compiled
2623: ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
2624: ** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various
2625: ** points during the compilation process, as logic is being created
2626: ** to perform various actions, the authorizer callback is invoked to
2627: ** see if those actions are allowed. ^The authorizer callback should
2628: ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
2629: ** specific action but allow the SQL statement to continue to be
2630: ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
2631: ** rejected with an error. ^If the authorizer callback returns
2632: ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
2633: ** then the [sqlite3_prepare_v2()] or equivalent call that triggered
2634: ** the authorizer will fail with an error message.
2635: **
2636: ** When the callback returns [SQLITE_OK], that means the operation
2637: ** requested is ok. ^When the callback returns [SQLITE_DENY], the
2638: ** [sqlite3_prepare_v2()] or equivalent call that triggered the
2639: ** authorizer will fail with an error message explaining that
2640: ** access is denied.
2641: **
2642: ** ^The first parameter to the authorizer callback is a copy of the third
2643: ** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
2644: ** to the callback is an integer [SQLITE_COPY | action code] that specifies
2645: ** the particular action to be authorized. ^The third through sixth parameters
2646: ** to the callback are zero-terminated strings that contain additional
2647: ** details about the action to be authorized.
2648: **
2649: ** ^If the action code is [SQLITE_READ]
2650: ** and the callback returns [SQLITE_IGNORE] then the
2651: ** [prepared statement] statement is constructed to substitute
2652: ** a NULL value in place of the table column that would have
2653: ** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE]
2654: ** return can be used to deny an untrusted user access to individual
2655: ** columns of a table.
2656: ** ^If the action code is [SQLITE_DELETE] and the callback returns
2657: ** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
2658: ** [truncate optimization] is disabled and all rows are deleted individually.
2659: **
2660: ** An authorizer is used when [sqlite3_prepare | preparing]
2661: ** SQL statements from an untrusted source, to ensure that the SQL statements
2662: ** do not try to access data they are not allowed to see, or that they do not
2663: ** try to execute malicious statements that damage the database. For
2664: ** example, an application may allow a user to enter arbitrary
2665: ** SQL queries for evaluation by a database. But the application does
2666: ** not want the user to be able to make arbitrary changes to the
2667: ** database. An authorizer could then be put in place while the
2668: ** user-entered SQL is being [sqlite3_prepare | prepared] that
2669: ** disallows everything except [SELECT] statements.
2670: **
2671: ** Applications that need to process SQL from untrusted sources
2672: ** might also consider lowering resource limits using [sqlite3_limit()]
2673: ** and limiting database size using the [max_page_count] [PRAGMA]
2674: ** in addition to using an authorizer.
2675: **
2676: ** ^(Only a single authorizer can be in place on a database connection
2677: ** at a time. Each call to sqlite3_set_authorizer overrides the
2678: ** previous call.)^ ^Disable the authorizer by installing a NULL callback.
2679: ** The authorizer is disabled by default.
2680: **
2681: ** The authorizer callback must not do anything that will modify
2682: ** the database connection that invoked the authorizer callback.
2683: ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2684: ** database connections for the meaning of "modify" in this paragraph.
2685: **
2686: ** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
2687: ** statement might be re-prepared during [sqlite3_step()] due to a
2688: ** schema change. Hence, the application should ensure that the
2689: ** correct authorizer callback remains in place during the [sqlite3_step()].
2690: **
2691: ** ^Note that the authorizer callback is invoked only during
2692: ** [sqlite3_prepare()] or its variants. Authorization is not
2693: ** performed during statement evaluation in [sqlite3_step()], unless
2694: ** as stated in the previous paragraph, sqlite3_step() invokes
2695: ** sqlite3_prepare_v2() to reprepare a statement after a schema change.
2696: */
2697: SQLITE_API int sqlite3_set_authorizer(
2698: sqlite3*,
2699: int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
2700: void *pUserData
2701: );
2702:
2703: /*
2704: ** CAPI3REF: Authorizer Return Codes
2705: **
2706: ** The [sqlite3_set_authorizer | authorizer callback function] must
2707: ** return either [SQLITE_OK] or one of these two constants in order
2708: ** to signal SQLite whether or not the action is permitted. See the
2709: ** [sqlite3_set_authorizer | authorizer documentation] for additional
2710: ** information.
2711: **
2712: ** Note that SQLITE_IGNORE is also used as a [conflict resolution mode]
2713: ** returned from the [sqlite3_vtab_on_conflict()] interface.
2714: */
2715: #define SQLITE_DENY 1 /* Abort the SQL statement with an error */
2716: #define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */
2717:
2718: /*
2719: ** CAPI3REF: Authorizer Action Codes
2720: **
2721: ** The [sqlite3_set_authorizer()] interface registers a callback function
2722: ** that is invoked to authorize certain SQL statement actions. The
2723: ** second parameter to the callback is an integer code that specifies
2724: ** what action is being authorized. These are the integer action codes that
2725: ** the authorizer callback may be passed.
2726: **
2727: ** These action code values signify what kind of operation is to be
2728: ** authorized. The 3rd and 4th parameters to the authorization
2729: ** callback function will be parameters or NULL depending on which of these
2730: ** codes is used as the second parameter. ^(The 5th parameter to the
2731: ** authorizer callback is the name of the database ("main", "temp",
2732: ** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback
2733: ** is the name of the inner-most trigger or view that is responsible for
2734: ** the access attempt or NULL if this access attempt is directly from
2735: ** top-level SQL code.
2736: */
2737: /******************************************* 3rd ************ 4th ***********/
2738: #define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */
2739: #define SQLITE_CREATE_TABLE 2 /* Table Name NULL */
2740: #define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */
2741: #define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */
2742: #define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */
2743: #define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */
2744: #define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */
2745: #define SQLITE_CREATE_VIEW 8 /* View Name NULL */
2746: #define SQLITE_DELETE 9 /* Table Name NULL */
2747: #define SQLITE_DROP_INDEX 10 /* Index Name Table Name */
2748: #define SQLITE_DROP_TABLE 11 /* Table Name NULL */
2749: #define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */
2750: #define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */
2751: #define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */
2752: #define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */
2753: #define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */
2754: #define SQLITE_DROP_VIEW 17 /* View Name NULL */
2755: #define SQLITE_INSERT 18 /* Table Name NULL */
2756: #define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */
2757: #define SQLITE_READ 20 /* Table Name Column Name */
2758: #define SQLITE_SELECT 21 /* NULL NULL */
2759: #define SQLITE_TRANSACTION 22 /* Operation NULL */
2760: #define SQLITE_UPDATE 23 /* Table Name Column Name */
2761: #define SQLITE_ATTACH 24 /* Filename NULL */
2762: #define SQLITE_DETACH 25 /* Database Name NULL */
2763: #define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */
2764: #define SQLITE_REINDEX 27 /* Index Name NULL */
2765: #define SQLITE_ANALYZE 28 /* Table Name NULL */
2766: #define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */
2767: #define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */
2768: #define SQLITE_FUNCTION 31 /* NULL Function Name */
2769: #define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */
2770: #define SQLITE_COPY 0 /* No longer used */
2771: #define SQLITE_RECURSIVE 33 /* NULL NULL */
2772:
2773: /*
2774: ** CAPI3REF: Tracing And Profiling Functions
2775: ** METHOD: sqlite3
2776: **
2777: ** These routines are deprecated. Use the [sqlite3_trace_v2()] interface
2778: ** instead of the routines described here.
2779: **
2780: ** These routines register callback functions that can be used for
2781: ** tracing and profiling the execution of SQL statements.
2782: **
2783: ** ^The callback function registered by sqlite3_trace() is invoked at
2784: ** various times when an SQL statement is being run by [sqlite3_step()].
2785: ** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
2786: ** SQL statement text as the statement first begins executing.
2787: ** ^(Additional sqlite3_trace() callbacks might occur
2788: ** as each triggered subprogram is entered. The callbacks for triggers
2789: ** contain a UTF-8 SQL comment that identifies the trigger.)^
2790: **
2791: ** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit
2792: ** the length of [bound parameter] expansion in the output of sqlite3_trace().
2793: **
2794: ** ^The callback function registered by sqlite3_profile() is invoked
2795: ** as each SQL statement finishes. ^The profile callback contains
2796: ** the original statement text and an estimate of wall-clock time
2797: ** of how long that statement took to run. ^The profile callback
2798: ** time is in units of nanoseconds, however the current implementation
2799: ** is only capable of millisecond resolution so the six least significant
2800: ** digits in the time are meaningless. Future versions of SQLite
2801: ** might provide greater resolution on the profiler callback. The
2802: ** sqlite3_profile() function is considered experimental and is
2803: ** subject to change in future versions of SQLite.
2804: */
2805: SQLITE_API SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*,
2806: void(*xTrace)(void*,const char*), void*);
2807: SQLITE_API SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*,
2808: void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
2809:
2810: /*
2811: ** CAPI3REF: SQL Trace Event Codes
2812: ** KEYWORDS: SQLITE_TRACE
2813: **
2814: ** These constants identify classes of events that can be monitored
2815: ** using the [sqlite3_trace_v2()] tracing logic. The third argument
2816: ** to [sqlite3_trace_v2()] is an OR-ed combination of one or more of
2817: ** the following constants. ^The first argument to the trace callback
2818: ** is one of the following constants.
2819: **
2820: ** New tracing constants may be added in future releases.
2821: **
2822: ** ^A trace callback has four arguments: xCallback(T,C,P,X).
2823: ** ^The T argument is one of the integer type codes above.
2824: ** ^The C argument is a copy of the context pointer passed in as the
2825: ** fourth argument to [sqlite3_trace_v2()].
2826: ** The P and X arguments are pointers whose meanings depend on T.
2827: **
2828: ** <dl>
2829: ** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt>
2830: ** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement
2831: ** first begins running and possibly at other times during the
2832: ** execution of the prepared statement, such as at the start of each
2833: ** trigger subprogram. ^The P argument is a pointer to the
2834: ** [prepared statement]. ^The X argument is a pointer to a string which
2835: ** is the unexpanded SQL text of the prepared statement or an SQL comment
2836: ** that indicates the invocation of a trigger. ^The callback can compute
2837: ** the same text that would have been returned by the legacy [sqlite3_trace()]
2838: ** interface by using the X argument when X begins with "--" and invoking
2839: ** [sqlite3_expanded_sql(P)] otherwise.
2840: **
2841: ** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt>
2842: ** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same
2843: ** information as is provided by the [sqlite3_profile()] callback.
2844: ** ^The P argument is a pointer to the [prepared statement] and the
2845: ** X argument points to a 64-bit integer which is the estimated of
2846: ** the number of nanosecond that the prepared statement took to run.
2847: ** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes.
2848: **
2849: ** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt>
2850: ** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared
2851: ** statement generates a single row of result.
2852: ** ^The P argument is a pointer to the [prepared statement] and the
2853: ** X argument is unused.
2854: **
2855: ** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt>
2856: ** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database
2857: ** connection closes.
2858: ** ^The P argument is a pointer to the [database connection] object
2859: ** and the X argument is unused.
2860: ** </dl>
2861: */
2862: #define SQLITE_TRACE_STMT 0x01
2863: #define SQLITE_TRACE_PROFILE 0x02
2864: #define SQLITE_TRACE_ROW 0x04
2865: #define SQLITE_TRACE_CLOSE 0x08
2866:
2867: /*
2868: ** CAPI3REF: SQL Trace Hook
2869: ** METHOD: sqlite3
2870: **
2871: ** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback
2872: ** function X against [database connection] D, using property mask M
2873: ** and context pointer P. ^If the X callback is
2874: ** NULL or if the M mask is zero, then tracing is disabled. The
2875: ** M argument should be the bitwise OR-ed combination of
2876: ** zero or more [SQLITE_TRACE] constants.
2877: **
2878: ** ^Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides
2879: ** (cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2().
2880: **
2881: ** ^The X callback is invoked whenever any of the events identified by
2882: ** mask M occur. ^The integer return value from the callback is currently
2883: ** ignored, though this may change in future releases. Callback
2884: ** implementations should return zero to ensure future compatibility.
2885: **
2886: ** ^A trace callback is invoked with four arguments: callback(T,C,P,X).
2887: ** ^The T argument is one of the [SQLITE_TRACE]
2888: ** constants to indicate why the callback was invoked.
2889: ** ^The C argument is a copy of the context pointer.
2890: ** The P and X arguments are pointers whose meanings depend on T.
2891: **
2892: ** The sqlite3_trace_v2() interface is intended to replace the legacy
2893: ** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which
2894: ** are deprecated.
2895: */
2896: SQLITE_API int sqlite3_trace_v2(
2897: sqlite3*,
2898: unsigned uMask,
2899: int(*xCallback)(unsigned,void*,void*,void*),
2900: void *pCtx
2901: );
2902:
2903: /*
2904: ** CAPI3REF: Query Progress Callbacks
2905: ** METHOD: sqlite3
2906: **
2907: ** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
2908: ** function X to be invoked periodically during long running calls to
2909: ** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for
2910: ** database connection D. An example use for this
2911: ** interface is to keep a GUI updated during a large query.
2912: **
2913: ** ^The parameter P is passed through as the only parameter to the
2914: ** callback function X. ^The parameter N is the approximate number of
2915: ** [virtual machine instructions] that are evaluated between successive
2916: ** invocations of the callback X. ^If N is less than one then the progress
2917: ** handler is disabled.
2918: **
2919: ** ^Only a single progress handler may be defined at one time per
2920: ** [database connection]; setting a new progress handler cancels the
2921: ** old one. ^Setting parameter X to NULL disables the progress handler.
2922: ** ^The progress handler is also disabled by setting N to a value less
2923: ** than 1.
2924: **
2925: ** ^If the progress callback returns non-zero, the operation is
2926: ** interrupted. This feature can be used to implement a
2927: ** "Cancel" button on a GUI progress dialog box.
2928: **
2929: ** The progress handler callback must not do anything that will modify
2930: ** the database connection that invoked the progress handler.
2931: ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2932: ** database connections for the meaning of "modify" in this paragraph.
2933: **
2934: */
2935: SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
2936:
2937: /*
2938: ** CAPI3REF: Opening A New Database Connection
2939: ** CONSTRUCTOR: sqlite3
2940: **
2941: ** ^These routines open an SQLite database file as specified by the
2942: ** filename argument. ^The filename argument is interpreted as UTF-8 for
2943: ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
2944: ** order for sqlite3_open16(). ^(A [database connection] handle is usually
2945: ** returned in *ppDb, even if an error occurs. The only exception is that
2946: ** if SQLite is unable to allocate memory to hold the [sqlite3] object,
2947: ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
2948: ** object.)^ ^(If the database is opened (and/or created) successfully, then
2949: ** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The
2950: ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
2951: ** an English language description of the error following a failure of any
2952: ** of the sqlite3_open() routines.
2953: **
2954: ** ^The default encoding will be UTF-8 for databases created using
2955: ** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases
2956: ** created using sqlite3_open16() will be UTF-16 in the native byte order.
2957: **
2958: ** Whether or not an error occurs when it is opened, resources
2959: ** associated with the [database connection] handle should be released by
2960: ** passing it to [sqlite3_close()] when it is no longer required.
2961: **
2962: ** The sqlite3_open_v2() interface works like sqlite3_open()
2963: ** except that it accepts two additional parameters for additional control
2964: ** over the new database connection. ^(The flags parameter to
2965: ** sqlite3_open_v2() can take one of
2966: ** the following three values, optionally combined with the
2967: ** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE],
2968: ** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^
2969: **
2970: ** <dl>
2971: ** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
2972: ** <dd>The database is opened in read-only mode. If the database does not
2973: ** already exist, an error is returned.</dd>)^
2974: **
2975: ** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
2976: ** <dd>The database is opened for reading and writing if possible, or reading
2977: ** only if the file is write protected by the operating system. In either
2978: ** case the database must already exist, otherwise an error is returned.</dd>)^
2979: **
2980: ** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
2981: ** <dd>The database is opened for reading and writing, and is created if
2982: ** it does not already exist. This is the behavior that is always used for
2983: ** sqlite3_open() and sqlite3_open16().</dd>)^
2984: ** </dl>
2985: **
2986: ** If the 3rd parameter to sqlite3_open_v2() is not one of the
2987: ** combinations shown above optionally combined with other
2988: ** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits]
2989: ** then the behavior is undefined.
2990: **
2991: ** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection
2992: ** opens in the multi-thread [threading mode] as long as the single-thread
2993: ** mode has not been set at compile-time or start-time. ^If the
2994: ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens
2995: ** in the serialized [threading mode] unless single-thread was
2996: ** previously selected at compile-time or start-time.
2997: ** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be
2998: ** eligible to use [shared cache mode], regardless of whether or not shared
2999: ** cache is enabled using [sqlite3_enable_shared_cache()]. ^The
3000: ** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not
3001: ** participate in [shared cache mode] even if it is enabled.
3002: **
3003: ** ^The fourth parameter to sqlite3_open_v2() is the name of the
3004: ** [sqlite3_vfs] object that defines the operating system interface that
3005: ** the new database connection should use. ^If the fourth parameter is
3006: ** a NULL pointer then the default [sqlite3_vfs] object is used.
3007: **
3008: ** ^If the filename is ":memory:", then a private, temporary in-memory database
3009: ** is created for the connection. ^This in-memory database will vanish when
3010: ** the database connection is closed. Future versions of SQLite might
3011: ** make use of additional special filenames that begin with the ":" character.
3012: ** It is recommended that when a database filename actually does begin with
3013: ** a ":" character you should prefix the filename with a pathname such as
3014: ** "./" to avoid ambiguity.
3015: **
3016: ** ^If the filename is an empty string, then a private, temporary
3017: ** on-disk database will be created. ^This private database will be
3018: ** automatically deleted as soon as the database connection is closed.
3019: **
3020: ** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
3021: **
3022: ** ^If [URI filename] interpretation is enabled, and the filename argument
3023: ** begins with "file:", then the filename is interpreted as a URI. ^URI
3024: ** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
3025: ** set in the fourth argument to sqlite3_open_v2(), or if it has
3026: ** been enabled globally using the [SQLITE_CONFIG_URI] option with the
3027: ** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
3028: ** As of SQLite version 3.7.7, URI filename interpretation is turned off
3029: ** by default, but future releases of SQLite might enable URI filename
3030: ** interpretation by default. See "[URI filenames]" for additional
3031: ** information.
3032: **
3033: ** URI filenames are parsed according to RFC 3986. ^If the URI contains an
3034: ** authority, then it must be either an empty string or the string
3035: ** "localhost". ^If the authority is not an empty string or "localhost", an
3036: ** error is returned to the caller. ^The fragment component of a URI, if
3037: ** present, is ignored.
3038: **
3039: ** ^SQLite uses the path component of the URI as the name of the disk file
3040: ** which contains the database. ^If the path begins with a '/' character,
3041: ** then it is interpreted as an absolute path. ^If the path does not begin
3042: ** with a '/' (meaning that the authority section is omitted from the URI)
3043: ** then the path is interpreted as a relative path.
3044: ** ^(On windows, the first component of an absolute path
3045: ** is a drive specification (e.g. "C:").)^
3046: **
3047: ** [[core URI query parameters]]
3048: ** The query component of a URI may contain parameters that are interpreted
3049: ** either by SQLite itself, or by a [VFS | custom VFS implementation].
3050: ** SQLite and its built-in [VFSes] interpret the
3051: ** following query parameters:
3052: **
3053: ** <ul>
3054: ** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
3055: ** a VFS object that provides the operating system interface that should
3056: ** be used to access the database file on disk. ^If this option is set to
3057: ** an empty string the default VFS object is used. ^Specifying an unknown
3058: ** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
3059: ** present, then the VFS specified by the option takes precedence over
3060: ** the value passed as the fourth parameter to sqlite3_open_v2().
3061: **
3062: ** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw",
3063: ** "rwc", or "memory". Attempting to set it to any other value is
3064: ** an error)^.
3065: ** ^If "ro" is specified, then the database is opened for read-only
3066: ** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the
3067: ** third argument to sqlite3_open_v2(). ^If the mode option is set to
3068: ** "rw", then the database is opened for read-write (but not create)
3069: ** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had
3070: ** been set. ^Value "rwc" is equivalent to setting both
3071: ** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is
3072: ** set to "memory" then a pure [in-memory database] that never reads
3073: ** or writes from disk is used. ^It is an error to specify a value for
3074: ** the mode parameter that is less restrictive than that specified by
3075: ** the flags passed in the third parameter to sqlite3_open_v2().
3076: **
3077: ** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
3078: ** "private". ^Setting it to "shared" is equivalent to setting the
3079: ** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
3080: ** sqlite3_open_v2(). ^Setting the cache parameter to "private" is
3081: ** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
3082: ** ^If sqlite3_open_v2() is used and the "cache" parameter is present in
3083: ** a URI filename, its value overrides any behavior requested by setting
3084: ** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.
3085: **
3086: ** <li> <b>psow</b>: ^The psow parameter indicates whether or not the
3087: ** [powersafe overwrite] property does or does not apply to the
3088: ** storage media on which the database file resides.
3089: **
3090: ** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter
3091: ** which if set disables file locking in rollback journal modes. This
3092: ** is useful for accessing a database on a filesystem that does not
3093: ** support locking. Caution: Database corruption might result if two
3094: ** or more processes write to the same database and any one of those
3095: ** processes uses nolock=1.
3096: **
3097: ** <li> <b>immutable</b>: ^The immutable parameter is a boolean query
3098: ** parameter that indicates that the database file is stored on
3099: ** read-only media. ^When immutable is set, SQLite assumes that the
3100: ** database file cannot be changed, even by a process with higher
3101: ** privilege, and so the database is opened read-only and all locking
3102: ** and change detection is disabled. Caution: Setting the immutable
3103: ** property on a database file that does in fact change can result
3104: ** in incorrect query results and/or [SQLITE_CORRUPT] errors.
3105: ** See also: [SQLITE_IOCAP_IMMUTABLE].
3106: **
3107: ** </ul>
3108: **
3109: ** ^Specifying an unknown parameter in the query component of a URI is not an
3110: ** error. Future versions of SQLite might understand additional query
3111: ** parameters. See "[query parameters with special meaning to SQLite]" for
3112: ** additional information.
3113: **
3114: ** [[URI filename examples]] <h3>URI filename examples</h3>
3115: **
3116: ** <table border="1" align=center cellpadding=5>
3117: ** <tr><th> URI filenames <th> Results
3118: ** <tr><td> file:data.db <td>
3119: ** Open the file "data.db" in the current directory.
3120: ** <tr><td> file:/home/fred/data.db<br>
3121: ** file:///home/fred/data.db <br>
3122: ** file://localhost/home/fred/data.db <br> <td>
3123: ** Open the database file "/home/fred/data.db".
3124: ** <tr><td> file://darkstar/home/fred/data.db <td>
3125: ** An error. "darkstar" is not a recognized authority.
3126: ** <tr><td style="white-space:nowrap">
3127: ** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
3128: ** <td> Windows only: Open the file "data.db" on fred's desktop on drive
3129: ** C:. Note that the %20 escaping in this example is not strictly
3130: ** necessary - space characters can be used literally
3131: ** in URI filenames.
3132: ** <tr><td> file:data.db?mode=ro&cache=private <td>
3133: ** Open file "data.db" in the current directory for read-only access.
3134: ** Regardless of whether or not shared-cache mode is enabled by
3135: ** default, use a private cache.
3136: ** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td>
3137: ** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile"
3138: ** that uses dot-files in place of posix advisory locking.
3139: ** <tr><td> file:data.db?mode=readonly <td>
3140: ** An error. "readonly" is not a valid option for the "mode" parameter.
3141: ** </table>
3142: **
3143: ** ^URI hexadecimal escape sequences (%HH) are supported within the path and
3144: ** query components of a URI. A hexadecimal escape sequence consists of a
3145: ** percent sign - "%" - followed by exactly two hexadecimal digits
3146: ** specifying an octet value. ^Before the path or query components of a
3147: ** URI filename are interpreted, they are encoded using UTF-8 and all
3148: ** hexadecimal escape sequences replaced by a single byte containing the
3149: ** corresponding octet. If this process generates an invalid UTF-8 encoding,
3150: ** the results are undefined.
3151: **
3152: ** <b>Note to Windows users:</b> The encoding used for the filename argument
3153: ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
3154: ** codepage is currently defined. Filenames containing international
3155: ** characters must be converted to UTF-8 prior to passing them into
3156: ** sqlite3_open() or sqlite3_open_v2().
3157: **
3158: ** <b>Note to Windows Runtime users:</b> The temporary directory must be set
3159: ** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various
3160: ** features that require the use of temporary files may fail.
3161: **
3162: ** See also: [sqlite3_temp_directory]
3163: */
3164: SQLITE_API int sqlite3_open(
3165: const char *filename, /* Database filename (UTF-8) */
3166: sqlite3 **ppDb /* OUT: SQLite db handle */
3167: );
3168: SQLITE_API int sqlite3_open16(
3169: const void *filename, /* Database filename (UTF-16) */
3170: sqlite3 **ppDb /* OUT: SQLite db handle */
3171: );
3172: SQLITE_API int sqlite3_open_v2(
3173: const char *filename, /* Database filename (UTF-8) */
3174: sqlite3 **ppDb, /* OUT: SQLite db handle */
3175: int flags, /* Flags */
3176: const char *zVfs /* Name of VFS module to use */
3177: );
3178:
3179: /*
3180: ** CAPI3REF: Obtain Values For URI Parameters
3181: **
3182: ** These are utility routines, useful to VFS implementations, that check
3183: ** to see if a database file was a URI that contained a specific query
3184: ** parameter, and if so obtains the value of that query parameter.
3185: **
3186: ** If F is the database filename pointer passed into the xOpen() method of
3187: ** a VFS implementation when the flags parameter to xOpen() has one or
3188: ** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and
3189: ** P is the name of the query parameter, then
3190: ** sqlite3_uri_parameter(F,P) returns the value of the P
3191: ** parameter if it exists or a NULL pointer if P does not appear as a
3192: ** query parameter on F. If P is a query parameter of F
3193: ** has no explicit value, then sqlite3_uri_parameter(F,P) returns
3194: ** a pointer to an empty string.
3195: **
3196: ** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
3197: ** parameter and returns true (1) or false (0) according to the value
3198: ** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
3199: ** value of query parameter P is one of "yes", "true", or "on" in any
3200: ** case or if the value begins with a non-zero number. The
3201: ** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
3202: ** query parameter P is one of "no", "false", or "off" in any case or
3203: ** if the value begins with a numeric zero. If P is not a query
3204: ** parameter on F or if the value of P is does not match any of the
3205: ** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).
3206: **
3207: ** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
3208: ** 64-bit signed integer and returns that integer, or D if P does not
3209: ** exist. If the value of P is something other than an integer, then
3210: ** zero is returned.
3211: **
3212: ** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
3213: ** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and
3214: ** is not a database file pathname pointer that SQLite passed into the xOpen
3215: ** VFS method, then the behavior of this routine is undefined and probably
3216: ** undesirable.
3217: */
3218: SQLITE_API const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam);
3219: SQLITE_API int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault);
3220: SQLITE_API sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64);
3221:
3222:
3223: /*
3224: ** CAPI3REF: Error Codes And Messages
3225: ** METHOD: sqlite3
3226: **
3227: ** ^If the most recent sqlite3_* API call associated with
3228: ** [database connection] D failed, then the sqlite3_errcode(D) interface
3229: ** returns the numeric [result code] or [extended result code] for that
3230: ** API call.
3231: ** If the most recent API call was successful,
3232: ** then the return value from sqlite3_errcode() is undefined.
3233: ** ^The sqlite3_extended_errcode()
3234: ** interface is the same except that it always returns the
3235: ** [extended result code] even when extended result codes are
3236: ** disabled.
3237: **
3238: ** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
3239: ** text that describes the error, as either UTF-8 or UTF-16 respectively.
3240: ** ^(Memory to hold the error message string is managed internally.
3241: ** The application does not need to worry about freeing the result.
3242: ** However, the error string might be overwritten or deallocated by
3243: ** subsequent calls to other SQLite interface functions.)^
3244: **
3245: ** ^The sqlite3_errstr() interface returns the English-language text
3246: ** that describes the [result code], as UTF-8.
3247: ** ^(Memory to hold the error message string is managed internally
3248: ** and must not be freed by the application)^.
3249: **
3250: ** When the serialized [threading mode] is in use, it might be the
3251: ** case that a second error occurs on a separate thread in between
3252: ** the time of the first error and the call to these interfaces.
3253: ** When that happens, the second error will be reported since these
3254: ** interfaces always report the most recent result. To avoid
3255: ** this, each thread can obtain exclusive use of the [database connection] D
3256: ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
3257: ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
3258: ** all calls to the interfaces listed here are completed.
3259: **
3260: ** If an interface fails with SQLITE_MISUSE, that means the interface
3261: ** was invoked incorrectly by the application. In that case, the
3262: ** error code and message may or may not be set.
3263: */
3264: SQLITE_API int sqlite3_errcode(sqlite3 *db);
3265: SQLITE_API int sqlite3_extended_errcode(sqlite3 *db);
3266: SQLITE_API const char *sqlite3_errmsg(sqlite3*);
3267: SQLITE_API const void *sqlite3_errmsg16(sqlite3*);
3268: SQLITE_API const char *sqlite3_errstr(int);
3269:
3270: /*
3271: ** CAPI3REF: Prepared Statement Object
3272: ** KEYWORDS: {prepared statement} {prepared statements}
3273: **
3274: ** An instance of this object represents a single SQL statement that
3275: ** has been compiled into binary form and is ready to be evaluated.
3276: **
3277: ** Think of each SQL statement as a separate computer program. The
3278: ** original SQL text is source code. A prepared statement object
3279: ** is the compiled object code. All SQL must be converted into a
3280: ** prepared statement before it can be run.
3281: **
3282: ** The life-cycle of a prepared statement object usually goes like this:
3283: **
3284: ** <ol>
3285: ** <li> Create the prepared statement object using [sqlite3_prepare_v2()].
3286: ** <li> Bind values to [parameters] using the sqlite3_bind_*()
3287: ** interfaces.
3288: ** <li> Run the SQL by calling [sqlite3_step()] one or more times.
3289: ** <li> Reset the prepared statement using [sqlite3_reset()] then go back
3290: ** to step 2. Do this zero or more times.
3291: ** <li> Destroy the object using [sqlite3_finalize()].
3292: ** </ol>
3293: */
3294: typedef struct sqlite3_stmt sqlite3_stmt;
3295:
3296: /*
3297: ** CAPI3REF: Run-time Limits
3298: ** METHOD: sqlite3
3299: **
3300: ** ^(This interface allows the size of various constructs to be limited
3301: ** on a connection by connection basis. The first parameter is the
3302: ** [database connection] whose limit is to be set or queried. The
3303: ** second parameter is one of the [limit categories] that define a
3304: ** class of constructs to be size limited. The third parameter is the
3305: ** new limit for that construct.)^
3306: **
3307: ** ^If the new limit is a negative number, the limit is unchanged.
3308: ** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
3309: ** [limits | hard upper bound]
3310: ** set at compile-time by a C preprocessor macro called
3311: ** [limits | SQLITE_MAX_<i>NAME</i>].
3312: ** (The "_LIMIT_" in the name is changed to "_MAX_".))^
3313: ** ^Attempts to increase a limit above its hard upper bound are
3314: ** silently truncated to the hard upper bound.
3315: **
3316: ** ^Regardless of whether or not the limit was changed, the
3317: ** [sqlite3_limit()] interface returns the prior value of the limit.
3318: ** ^Hence, to find the current value of a limit without changing it,
3319: ** simply invoke this interface with the third parameter set to -1.
3320: **
3321: ** Run-time limits are intended for use in applications that manage
3322: ** both their own internal database and also databases that are controlled
3323: ** by untrusted external sources. An example application might be a
3324: ** web browser that has its own databases for storing history and
3325: ** separate databases controlled by JavaScript applications downloaded
3326: ** off the Internet. The internal databases can be given the
3327: ** large, default limits. Databases managed by external sources can
3328: ** be given much smaller limits designed to prevent a denial of service
3329: ** attack. Developers might also want to use the [sqlite3_set_authorizer()]
3330: ** interface to further control untrusted SQL. The size of the database
3331: ** created by an untrusted script can be contained using the
3332: ** [max_page_count] [PRAGMA].
3333: **
3334: ** New run-time limit categories may be added in future releases.
3335: */
3336: SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal);
3337:
3338: /*
3339: ** CAPI3REF: Run-Time Limit Categories
3340: ** KEYWORDS: {limit category} {*limit categories}
3341: **
3342: ** These constants define various performance limits
3343: ** that can be lowered at run-time using [sqlite3_limit()].
3344: ** The synopsis of the meanings of the various limits is shown below.
3345: ** Additional information is available at [limits | Limits in SQLite].
3346: **
3347: ** <dl>
3348: ** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt>
3349: ** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
3350: **
3351: ** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
3352: ** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
3353: **
3354: ** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt>
3355: ** <dd>The maximum number of columns in a table definition or in the
3356: ** result set of a [SELECT] or the maximum number of columns in an index
3357: ** or in an ORDER BY or GROUP BY clause.</dd>)^
3358: **
3359: ** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
3360: ** <dd>The maximum depth of the parse tree on any expression.</dd>)^
3361: **
3362: ** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
3363: ** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
3364: **
3365: ** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
3366: ** <dd>The maximum number of instructions in a virtual machine program
3367: ** used to implement an SQL statement. This limit is not currently
3368: ** enforced, though that might be added in some future release of
3369: ** SQLite.</dd>)^
3370: **
3371: ** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
3372: ** <dd>The maximum number of arguments on a function.</dd>)^
3373: **
3374: ** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
3375: ** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
3376: **
3377: ** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]]
3378: ** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
3379: ** <dd>The maximum length of the pattern argument to the [LIKE] or
3380: ** [GLOB] operators.</dd>)^
3381: **
3382: ** [[SQLITE_LIMIT_VARIABLE_NUMBER]]
3383: ** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
3384: ** <dd>The maximum index number of any [parameter] in an SQL statement.)^
3385: **
3386: ** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
3387: ** <dd>The maximum depth of recursion for triggers.</dd>)^
3388: **
3389: ** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt>
3390: ** <dd>The maximum number of auxiliary worker threads that a single
3391: ** [prepared statement] may start.</dd>)^
3392: ** </dl>
3393: */
3394: #define SQLITE_LIMIT_LENGTH 0
3395: #define SQLITE_LIMIT_SQL_LENGTH 1
3396: #define SQLITE_LIMIT_COLUMN 2
3397: #define SQLITE_LIMIT_EXPR_DEPTH 3
3398: #define SQLITE_LIMIT_COMPOUND_SELECT 4
3399: #define SQLITE_LIMIT_VDBE_OP 5
3400: #define SQLITE_LIMIT_FUNCTION_ARG 6
3401: #define SQLITE_LIMIT_ATTACHED 7
3402: #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8
3403: #define SQLITE_LIMIT_VARIABLE_NUMBER 9
3404: #define SQLITE_LIMIT_TRIGGER_DEPTH 10
3405: #define SQLITE_LIMIT_WORKER_THREADS 11
3406:
3407: /*
3408: ** CAPI3REF: Compiling An SQL Statement
3409: ** KEYWORDS: {SQL statement compiler}
3410: ** METHOD: sqlite3
3411: ** CONSTRUCTOR: sqlite3_stmt
3412: **
3413: ** To execute an SQL query, it must first be compiled into a byte-code
3414: ** program using one of these routines.
3415: **
3416: ** The first argument, "db", is a [database connection] obtained from a
3417: ** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
3418: ** [sqlite3_open16()]. The database connection must not have been closed.
3419: **
3420: ** The second argument, "zSql", is the statement to be compiled, encoded
3421: ** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2()
3422: ** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2()
3423: ** use UTF-16.
3424: **
3425: ** ^If the nByte argument is negative, then zSql is read up to the
3426: ** first zero terminator. ^If nByte is positive, then it is the
3427: ** number of bytes read from zSql. ^If nByte is zero, then no prepared
3428: ** statement is generated.
3429: ** If the caller knows that the supplied string is nul-terminated, then
3430: ** there is a small performance advantage to passing an nByte parameter that
3431: ** is the number of bytes in the input string <i>including</i>
3432: ** the nul-terminator.
3433: **
3434: ** ^If pzTail is not NULL then *pzTail is made to point to the first byte
3435: ** past the end of the first SQL statement in zSql. These routines only
3436: ** compile the first statement in zSql, so *pzTail is left pointing to
3437: ** what remains uncompiled.
3438: **
3439: ** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
3440: ** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set
3441: ** to NULL. ^If the input text contains no SQL (if the input is an empty
3442: ** string or a comment) then *ppStmt is set to NULL.
3443: ** The calling procedure is responsible for deleting the compiled
3444: ** SQL statement using [sqlite3_finalize()] after it has finished with it.
3445: ** ppStmt may not be NULL.
3446: **
3447: ** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
3448: ** otherwise an [error code] is returned.
3449: **
3450: ** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are
3451: ** recommended for all new programs. The two older interfaces are retained
3452: ** for backwards compatibility, but their use is discouraged.
3453: ** ^In the "v2" interfaces, the prepared statement
3454: ** that is returned (the [sqlite3_stmt] object) contains a copy of the
3455: ** original SQL text. This causes the [sqlite3_step()] interface to
3456: ** behave differently in three ways:
3457: **
3458: ** <ol>
3459: ** <li>
3460: ** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
3461: ** always used to do, [sqlite3_step()] will automatically recompile the SQL
3462: ** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY]
3463: ** retries will occur before sqlite3_step() gives up and returns an error.
3464: ** </li>
3465: **
3466: ** <li>
3467: ** ^When an error occurs, [sqlite3_step()] will return one of the detailed
3468: ** [error codes] or [extended error codes]. ^The legacy behavior was that
3469: ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
3470: ** and the application would have to make a second call to [sqlite3_reset()]
3471: ** in order to find the underlying cause of the problem. With the "v2" prepare
3472: ** interfaces, the underlying reason for the error is returned immediately.
3473: ** </li>
3474: **
3475: ** <li>
3476: ** ^If the specific value bound to [parameter | host parameter] in the
3477: ** WHERE clause might influence the choice of query plan for a statement,
3478: ** then the statement will be automatically recompiled, as if there had been
3479: ** a schema change, on the first [sqlite3_step()] call following any change
3480: ** to the [sqlite3_bind_text | bindings] of that [parameter].
3481: ** ^The specific value of WHERE-clause [parameter] might influence the
3482: ** choice of query plan if the parameter is the left-hand side of a [LIKE]
3483: ** or [GLOB] operator or if the parameter is compared to an indexed column
3484: ** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled.
3485: ** </li>
3486: ** </ol>
3487: */
3488: SQLITE_API int sqlite3_prepare(
3489: sqlite3 *db, /* Database handle */
3490: const char *zSql, /* SQL statement, UTF-8 encoded */
3491: int nByte, /* Maximum length of zSql in bytes. */
3492: sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3493: const char **pzTail /* OUT: Pointer to unused portion of zSql */
3494: );
3495: SQLITE_API int sqlite3_prepare_v2(
3496: sqlite3 *db, /* Database handle */
3497: const char *zSql, /* SQL statement, UTF-8 encoded */
3498: int nByte, /* Maximum length of zSql in bytes. */
3499: sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3500: const char **pzTail /* OUT: Pointer to unused portion of zSql */
3501: );
3502: SQLITE_API int sqlite3_prepare16(
3503: sqlite3 *db, /* Database handle */
3504: const void *zSql, /* SQL statement, UTF-16 encoded */
3505: int nByte, /* Maximum length of zSql in bytes. */
3506: sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3507: const void **pzTail /* OUT: Pointer to unused portion of zSql */
3508: );
3509: SQLITE_API int sqlite3_prepare16_v2(
3510: sqlite3 *db, /* Database handle */
3511: const void *zSql, /* SQL statement, UTF-16 encoded */
3512: int nByte, /* Maximum length of zSql in bytes. */
3513: sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3514: const void **pzTail /* OUT: Pointer to unused portion of zSql */
3515: );
3516:
3517: /*
3518: ** CAPI3REF: Retrieving Statement SQL
3519: ** METHOD: sqlite3_stmt
3520: **
3521: ** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8
3522: ** SQL text used to create [prepared statement] P if P was
3523: ** created by either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()].
3524: ** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8
3525: ** string containing the SQL text of prepared statement P with
3526: ** [bound parameters] expanded.
3527: **
3528: ** ^(For example, if a prepared statement is created using the SQL
3529: ** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345
3530: ** and parameter :xyz is unbound, then sqlite3_sql() will return
3531: ** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql()
3532: ** will return "SELECT 2345,NULL".)^
3533: **
3534: ** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory
3535: ** is available to hold the result, or if the result would exceed the
3536: ** the maximum string length determined by the [SQLITE_LIMIT_LENGTH].
3537: **
3538: ** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of
3539: ** bound parameter expansions. ^The [SQLITE_OMIT_TRACE] compile-time
3540: ** option causes sqlite3_expanded_sql() to always return NULL.
3541: **
3542: ** ^The string returned by sqlite3_sql(P) is managed by SQLite and is
3543: ** automatically freed when the prepared statement is finalized.
3544: ** ^The string returned by sqlite3_expanded_sql(P), on the other hand,
3545: ** is obtained from [sqlite3_malloc()] and must be free by the application
3546: ** by passing it to [sqlite3_free()].
3547: */
3548: SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt);
3549: SQLITE_API char *sqlite3_expanded_sql(sqlite3_stmt *pStmt);
3550:
3551: /*
3552: ** CAPI3REF: Determine If An SQL Statement Writes The Database
3553: ** METHOD: sqlite3_stmt
3554: **
3555: ** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
3556: ** and only if the [prepared statement] X makes no direct changes to
3557: ** the content of the database file.
3558: **
3559: ** Note that [application-defined SQL functions] or
3560: ** [virtual tables] might change the database indirectly as a side effect.
3561: ** ^(For example, if an application defines a function "eval()" that
3562: ** calls [sqlite3_exec()], then the following SQL statement would
3563: ** change the database file through side-effects:
3564: **
3565: ** <blockquote><pre>
3566: ** SELECT eval('DELETE FROM t1') FROM t2;
3567: ** </pre></blockquote>
3568: **
3569: ** But because the [SELECT] statement does not change the database file
3570: ** directly, sqlite3_stmt_readonly() would still return true.)^
3571: **
3572: ** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
3573: ** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
3574: ** since the statements themselves do not actually modify the database but
3575: ** rather they control the timing of when other statements modify the
3576: ** database. ^The [ATTACH] and [DETACH] statements also cause
3577: ** sqlite3_stmt_readonly() to return true since, while those statements
3578: ** change the configuration of a database connection, they do not make
3579: ** changes to the content of the database files on disk.
3580: */
3581: SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
3582:
3583: /*
3584: ** CAPI3REF: Determine If A Prepared Statement Has Been Reset
3585: ** METHOD: sqlite3_stmt
3586: **
3587: ** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
3588: ** [prepared statement] S has been stepped at least once using
3589: ** [sqlite3_step(S)] but has neither run to completion (returned
3590: ** [SQLITE_DONE] from [sqlite3_step(S)]) nor
3591: ** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S)
3592: ** interface returns false if S is a NULL pointer. If S is not a
3593: ** NULL pointer and is not a pointer to a valid [prepared statement]
3594: ** object, then the behavior is undefined and probably undesirable.
3595: **
3596: ** This interface can be used in combination [sqlite3_next_stmt()]
3597: ** to locate all prepared statements associated with a database
3598: ** connection that are in need of being reset. This can be used,
3599: ** for example, in diagnostic routines to search for prepared
3600: ** statements that are holding a transaction open.
3601: */
3602: SQLITE_API int sqlite3_stmt_busy(sqlite3_stmt*);
3603:
3604: /*
3605: ** CAPI3REF: Dynamically Typed Value Object
3606: ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
3607: **
3608: ** SQLite uses the sqlite3_value object to represent all values
3609: ** that can be stored in a database table. SQLite uses dynamic typing
3610: ** for the values it stores. ^Values stored in sqlite3_value objects
3611: ** can be integers, floating point values, strings, BLOBs, or NULL.
3612: **
3613: ** An sqlite3_value object may be either "protected" or "unprotected".
3614: ** Some interfaces require a protected sqlite3_value. Other interfaces
3615: ** will accept either a protected or an unprotected sqlite3_value.
3616: ** Every interface that accepts sqlite3_value arguments specifies
3617: ** whether or not it requires a protected sqlite3_value. The
3618: ** [sqlite3_value_dup()] interface can be used to construct a new
3619: ** protected sqlite3_value from an unprotected sqlite3_value.
3620: **
3621: ** The terms "protected" and "unprotected" refer to whether or not
3622: ** a mutex is held. An internal mutex is held for a protected
3623: ** sqlite3_value object but no mutex is held for an unprotected
3624: ** sqlite3_value object. If SQLite is compiled to be single-threaded
3625: ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
3626: ** or if SQLite is run in one of reduced mutex modes
3627: ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
3628: ** then there is no distinction between protected and unprotected
3629: ** sqlite3_value objects and they can be used interchangeably. However,
3630: ** for maximum code portability it is recommended that applications
3631: ** still make the distinction between protected and unprotected
3632: ** sqlite3_value objects even when not strictly required.
3633: **
3634: ** ^The sqlite3_value objects that are passed as parameters into the
3635: ** implementation of [application-defined SQL functions] are protected.
3636: ** ^The sqlite3_value object returned by
3637: ** [sqlite3_column_value()] is unprotected.
3638: ** Unprotected sqlite3_value objects may only be used with
3639: ** [sqlite3_result_value()] and [sqlite3_bind_value()].
3640: ** The [sqlite3_value_blob | sqlite3_value_type()] family of
3641: ** interfaces require protected sqlite3_value objects.
3642: */
3643: typedef struct Mem sqlite3_value;
3644:
3645: /*
3646: ** CAPI3REF: SQL Function Context Object
3647: **
3648: ** The context in which an SQL function executes is stored in an
3649: ** sqlite3_context object. ^A pointer to an sqlite3_context object
3650: ** is always first parameter to [application-defined SQL functions].
3651: ** The application-defined SQL function implementation will pass this
3652: ** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
3653: ** [sqlite3_aggregate_context()], [sqlite3_user_data()],
3654: ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
3655: ** and/or [sqlite3_set_auxdata()].
3656: */
3657: typedef struct sqlite3_context sqlite3_context;
3658:
3659: /*
3660: ** CAPI3REF: Binding Values To Prepared Statements
3661: ** KEYWORDS: {host parameter} {host parameters} {host parameter name}
3662: ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
3663: ** METHOD: sqlite3_stmt
3664: **
3665: ** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
3666: ** literals may be replaced by a [parameter] that matches one of following
3667: ** templates:
3668: **
3669: ** <ul>
3670: ** <li> ?
3671: ** <li> ?NNN
3672: ** <li> :VVV
3673: ** <li> @VVV
3674: ** <li> $VVV
3675: ** </ul>
3676: **
3677: ** In the templates above, NNN represents an integer literal,
3678: ** and VVV represents an alphanumeric identifier.)^ ^The values of these
3679: ** parameters (also called "host parameter names" or "SQL parameters")
3680: ** can be set using the sqlite3_bind_*() routines defined here.
3681: **
3682: ** ^The first argument to the sqlite3_bind_*() routines is always
3683: ** a pointer to the [sqlite3_stmt] object returned from
3684: ** [sqlite3_prepare_v2()] or its variants.
3685: **
3686: ** ^The second argument is the index of the SQL parameter to be set.
3687: ** ^The leftmost SQL parameter has an index of 1. ^When the same named
3688: ** SQL parameter is used more than once, second and subsequent
3689: ** occurrences have the same index as the first occurrence.
3690: ** ^The index for named parameters can be looked up using the
3691: ** [sqlite3_bind_parameter_index()] API if desired. ^The index
3692: ** for "?NNN" parameters is the value of NNN.
3693: ** ^The NNN value must be between 1 and the [sqlite3_limit()]
3694: ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999).
3695: **
3696: ** ^The third argument is the value to bind to the parameter.
3697: ** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16()
3698: ** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter
3699: ** is ignored and the end result is the same as sqlite3_bind_null().
3700: **
3701: ** ^(In those routines that have a fourth argument, its value is the
3702: ** number of bytes in the parameter. To be clear: the value is the
3703: ** number of <u>bytes</u> in the value, not the number of characters.)^
3704: ** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()
3705: ** is negative, then the length of the string is
3706: ** the number of bytes up to the first zero terminator.
3707: ** If the fourth parameter to sqlite3_bind_blob() is negative, then
3708: ** the behavior is undefined.
3709: ** If a non-negative fourth parameter is provided to sqlite3_bind_text()
3710: ** or sqlite3_bind_text16() or sqlite3_bind_text64() then
3711: ** that parameter must be the byte offset
3712: ** where the NUL terminator would occur assuming the string were NUL
3713: ** terminated. If any NUL characters occur at byte offsets less than
3714: ** the value of the fourth parameter then the resulting string value will
3715: ** contain embedded NULs. The result of expressions involving strings
3716: ** with embedded NULs is undefined.
3717: **
3718: ** ^The fifth argument to the BLOB and string binding interfaces
3719: ** is a destructor used to dispose of the BLOB or
3720: ** string after SQLite has finished with it. ^The destructor is called
3721: ** to dispose of the BLOB or string even if the call to bind API fails.
3722: ** ^If the fifth argument is
3723: ** the special value [SQLITE_STATIC], then SQLite assumes that the
3724: ** information is in static, unmanaged space and does not need to be freed.
3725: ** ^If the fifth argument has the value [SQLITE_TRANSIENT], then
3726: ** SQLite makes its own private copy of the data immediately, before
3727: ** the sqlite3_bind_*() routine returns.
3728: **
3729: ** ^The sixth argument to sqlite3_bind_text64() must be one of
3730: ** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]
3731: ** to specify the encoding of the text in the third parameter. If
3732: ** the sixth argument to sqlite3_bind_text64() is not one of the
3733: ** allowed values shown above, or if the text encoding is different
3734: ** from the encoding specified by the sixth parameter, then the behavior
3735: ** is undefined.
3736: **
3737: ** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
3738: ** is filled with zeroes. ^A zeroblob uses a fixed amount of memory
3739: ** (just an integer to hold its size) while it is being processed.
3740: ** Zeroblobs are intended to serve as placeholders for BLOBs whose
3741: ** content is later written using
3742: ** [sqlite3_blob_open | incremental BLOB I/O] routines.
3743: ** ^A negative value for the zeroblob results in a zero-length BLOB.
3744: **
3745: ** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
3746: ** for the [prepared statement] or with a prepared statement for which
3747: ** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
3748: ** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_()
3749: ** routine is passed a [prepared statement] that has been finalized, the
3750: ** result is undefined and probably harmful.
3751: **
3752: ** ^Bindings are not cleared by the [sqlite3_reset()] routine.
3753: ** ^Unbound parameters are interpreted as NULL.
3754: **
3755: ** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
3756: ** [error code] if anything goes wrong.
3757: ** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB
3758: ** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or
3759: ** [SQLITE_MAX_LENGTH].
3760: ** ^[SQLITE_RANGE] is returned if the parameter
3761: ** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails.
3762: **
3763: ** See also: [sqlite3_bind_parameter_count()],
3764: ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
3765: */
3766: SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
3767: SQLITE_API int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64,
3768: void(*)(void*));
3769: SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double);
3770: SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int);
3771: SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
3772: SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int);
3773: SQLITE_API int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*));
3774: SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
3775: SQLITE_API int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64,
3776: void(*)(void*), unsigned char encoding);
3777: SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
3778: SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
3779: SQLITE_API int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64);
3780:
3781: /*
3782: ** CAPI3REF: Number Of SQL Parameters
3783: ** METHOD: sqlite3_stmt
3784: **
3785: ** ^This routine can be used to find the number of [SQL parameters]
3786: ** in a [prepared statement]. SQL parameters are tokens of the
3787: ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
3788: ** placeholders for values that are [sqlite3_bind_blob | bound]
3789: ** to the parameters at a later time.
3790: **
3791: ** ^(This routine actually returns the index of the largest (rightmost)
3792: ** parameter. For all forms except ?NNN, this will correspond to the
3793: ** number of unique parameters. If parameters of the ?NNN form are used,
3794: ** there may be gaps in the list.)^
3795: **
3796: ** See also: [sqlite3_bind_blob|sqlite3_bind()],
3797: ** [sqlite3_bind_parameter_name()], and
3798: ** [sqlite3_bind_parameter_index()].
3799: */
3800: SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*);
3801:
3802: /*
3803: ** CAPI3REF: Name Of A Host Parameter
3804: ** METHOD: sqlite3_stmt
3805: **
3806: ** ^The sqlite3_bind_parameter_name(P,N) interface returns
3807: ** the name of the N-th [SQL parameter] in the [prepared statement] P.
3808: ** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
3809: ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
3810: ** respectively.
3811: ** In other words, the initial ":" or "$" or "@" or "?"
3812: ** is included as part of the name.)^
3813: ** ^Parameters of the form "?" without a following integer have no name
3814: ** and are referred to as "nameless" or "anonymous parameters".
3815: **
3816: ** ^The first host parameter has an index of 1, not 0.
3817: **
3818: ** ^If the value N is out of range or if the N-th parameter is
3819: ** nameless, then NULL is returned. ^The returned string is
3820: ** always in UTF-8 encoding even if the named parameter was
3821: ** originally specified as UTF-16 in [sqlite3_prepare16()] or
3822: ** [sqlite3_prepare16_v2()].
3823: **
3824: ** See also: [sqlite3_bind_blob|sqlite3_bind()],
3825: ** [sqlite3_bind_parameter_count()], and
3826: ** [sqlite3_bind_parameter_index()].
3827: */
3828: SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
3829:
3830: /*
3831: ** CAPI3REF: Index Of A Parameter With A Given Name
3832: ** METHOD: sqlite3_stmt
3833: **
3834: ** ^Return the index of an SQL parameter given its name. ^The
3835: ** index value returned is suitable for use as the second
3836: ** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero
3837: ** is returned if no matching parameter is found. ^The parameter
3838: ** name must be given in UTF-8 even if the original statement
3839: ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()].
3840: **
3841: ** See also: [sqlite3_bind_blob|sqlite3_bind()],
3842: ** [sqlite3_bind_parameter_count()], and
3843: ** [sqlite3_bind_parameter_name()].
3844: */
3845: SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
3846:
3847: /*
3848: ** CAPI3REF: Reset All Bindings On A Prepared Statement
3849: ** METHOD: sqlite3_stmt
3850: **
3851: ** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
3852: ** the [sqlite3_bind_blob | bindings] on a [prepared statement].
3853: ** ^Use this routine to reset all host parameters to NULL.
3854: */
3855: SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*);
3856:
3857: /*
3858: ** CAPI3REF: Number Of Columns In A Result Set
3859: ** METHOD: sqlite3_stmt
3860: **
3861: ** ^Return the number of columns in the result set returned by the
3862: ** [prepared statement]. ^This routine returns 0 if pStmt is an SQL
3863: ** statement that does not return data (for example an [UPDATE]).
3864: **
3865: ** See also: [sqlite3_data_count()]
3866: */
3867: SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt);
3868:
3869: /*
3870: ** CAPI3REF: Column Names In A Result Set
3871: ** METHOD: sqlite3_stmt
3872: **
3873: ** ^These routines return the name assigned to a particular column
3874: ** in the result set of a [SELECT] statement. ^The sqlite3_column_name()
3875: ** interface returns a pointer to a zero-terminated UTF-8 string
3876: ** and sqlite3_column_name16() returns a pointer to a zero-terminated
3877: ** UTF-16 string. ^The first parameter is the [prepared statement]
3878: ** that implements the [SELECT] statement. ^The second parameter is the
3879: ** column number. ^The leftmost column is number 0.
3880: **
3881: ** ^The returned string pointer is valid until either the [prepared statement]
3882: ** is destroyed by [sqlite3_finalize()] or until the statement is automatically
3883: ** reprepared by the first call to [sqlite3_step()] for a particular run
3884: ** or until the next call to
3885: ** sqlite3_column_name() or sqlite3_column_name16() on the same column.
3886: **
3887: ** ^If sqlite3_malloc() fails during the processing of either routine
3888: ** (for example during a conversion from UTF-8 to UTF-16) then a
3889: ** NULL pointer is returned.
3890: **
3891: ** ^The name of a result column is the value of the "AS" clause for
3892: ** that column, if there is an AS clause. If there is no AS clause
3893: ** then the name of the column is unspecified and may change from
3894: ** one release of SQLite to the next.
3895: */
3896: SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N);
3897: SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N);
3898:
3899: /*
3900: ** CAPI3REF: Source Of Data In A Query Result
3901: ** METHOD: sqlite3_stmt
3902: **
3903: ** ^These routines provide a means to determine the database, table, and
3904: ** table column that is the origin of a particular result column in
3905: ** [SELECT] statement.
3906: ** ^The name of the database or table or column can be returned as
3907: ** either a UTF-8 or UTF-16 string. ^The _database_ routines return
3908: ** the database name, the _table_ routines return the table name, and
3909: ** the origin_ routines return the column name.
3910: ** ^The returned string is valid until the [prepared statement] is destroyed
3911: ** using [sqlite3_finalize()] or until the statement is automatically
3912: ** reprepared by the first call to [sqlite3_step()] for a particular run
3913: ** or until the same information is requested
3914: ** again in a different encoding.
3915: **
3916: ** ^The names returned are the original un-aliased names of the
3917: ** database, table, and column.
3918: **
3919: ** ^The first argument to these interfaces is a [prepared statement].
3920: ** ^These functions return information about the Nth result column returned by
3921: ** the statement, where N is the second function argument.
3922: ** ^The left-most column is column 0 for these routines.
3923: **
3924: ** ^If the Nth column returned by the statement is an expression or
3925: ** subquery and is not a column value, then all of these functions return
3926: ** NULL. ^These routine might also return NULL if a memory allocation error
3927: ** occurs. ^Otherwise, they return the name of the attached database, table,
3928: ** or column that query result column was extracted from.
3929: **
3930: ** ^As with all other SQLite APIs, those whose names end with "16" return
3931: ** UTF-16 encoded strings and the other functions return UTF-8.
3932: **
3933: ** ^These APIs are only available if the library was compiled with the
3934: ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
3935: **
3936: ** If two or more threads call one or more of these routines against the same
3937: ** prepared statement and column at the same time then the results are
3938: ** undefined.
3939: **
3940: ** If two or more threads call one or more
3941: ** [sqlite3_column_database_name | column metadata interfaces]
3942: ** for the same [prepared statement] and result column
3943: ** at the same time then the results are undefined.
3944: */
3945: SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int);
3946: SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
3947: SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int);
3948: SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
3949: SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
3950: SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
3951:
3952: /*
3953: ** CAPI3REF: Declared Datatype Of A Query Result
3954: ** METHOD: sqlite3_stmt
3955: **
3956: ** ^(The first parameter is a [prepared statement].
3957: ** If this statement is a [SELECT] statement and the Nth column of the
3958: ** returned result set of that [SELECT] is a table column (not an
3959: ** expression or subquery) then the declared type of the table
3960: ** column is returned.)^ ^If the Nth column of the result set is an
3961: ** expression or subquery, then a NULL pointer is returned.
3962: ** ^The returned string is always UTF-8 encoded.
3963: **
3964: ** ^(For example, given the database schema:
3965: **
3966: ** CREATE TABLE t1(c1 VARIANT);
3967: **
3968: ** and the following statement to be compiled:
3969: **
3970: ** SELECT c1 + 1, c1 FROM t1;
3971: **
3972: ** this routine would return the string "VARIANT" for the second result
3973: ** column (i==1), and a NULL pointer for the first result column (i==0).)^
3974: **
3975: ** ^SQLite uses dynamic run-time typing. ^So just because a column
3976: ** is declared to contain a particular type does not mean that the
3977: ** data stored in that column is of the declared type. SQLite is
3978: ** strongly typed, but the typing is dynamic not static. ^Type
3979: ** is associated with individual values, not with the containers
3980: ** used to hold those values.
3981: */
3982: SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int);
3983: SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
3984:
3985: /*
3986: ** CAPI3REF: Evaluate An SQL Statement
3987: ** METHOD: sqlite3_stmt
3988: **
3989: ** After a [prepared statement] has been prepared using either
3990: ** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy
3991: ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
3992: ** must be called one or more times to evaluate the statement.
3993: **
3994: ** The details of the behavior of the sqlite3_step() interface depend
3995: ** on whether the statement was prepared using the newer "v2" interface
3996: ** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy
3997: ** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the
3998: ** new "v2" interface is recommended for new applications but the legacy
3999: ** interface will continue to be supported.
4000: **
4001: ** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
4002: ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
4003: ** ^With the "v2" interface, any of the other [result codes] or
4004: ** [extended result codes] might be returned as well.
4005: **
4006: ** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
4007: ** database locks it needs to do its job. ^If the statement is a [COMMIT]
4008: ** or occurs outside of an explicit transaction, then you can retry the
4009: ** statement. If the statement is not a [COMMIT] and occurs within an
4010: ** explicit transaction then you should rollback the transaction before
4011: ** continuing.
4012: **
4013: ** ^[SQLITE_DONE] means that the statement has finished executing
4014: ** successfully. sqlite3_step() should not be called again on this virtual
4015: ** machine without first calling [sqlite3_reset()] to reset the virtual
4016: ** machine back to its initial state.
4017: **
4018: ** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
4019: ** is returned each time a new row of data is ready for processing by the
4020: ** caller. The values may be accessed using the [column access functions].
4021: ** sqlite3_step() is called again to retrieve the next row of data.
4022: **
4023: ** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
4024: ** violation) has occurred. sqlite3_step() should not be called again on
4025: ** the VM. More information may be found by calling [sqlite3_errmsg()].
4026: ** ^With the legacy interface, a more specific error code (for example,
4027: ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
4028: ** can be obtained by calling [sqlite3_reset()] on the
4029: ** [prepared statement]. ^In the "v2" interface,
4030: ** the more specific error code is returned directly by sqlite3_step().
4031: **
4032: ** [SQLITE_MISUSE] means that the this routine was called inappropriately.
4033: ** Perhaps it was called on a [prepared statement] that has
4034: ** already been [sqlite3_finalize | finalized] or on one that had
4035: ** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could
4036: ** be the case that the same database connection is being used by two or
4037: ** more threads at the same moment in time.
4038: **
4039: ** For all versions of SQLite up to and including 3.6.23.1, a call to
4040: ** [sqlite3_reset()] was required after sqlite3_step() returned anything
4041: ** other than [SQLITE_ROW] before any subsequent invocation of
4042: ** sqlite3_step(). Failure to reset the prepared statement using
4043: ** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
4044: ** sqlite3_step(). But after version 3.6.23.1, sqlite3_step() began
4045: ** calling [sqlite3_reset()] automatically in this circumstance rather
4046: ** than returning [SQLITE_MISUSE]. This is not considered a compatibility
4047: ** break because any application that ever receives an SQLITE_MISUSE error
4048: ** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option
4049: ** can be used to restore the legacy behavior.
4050: **
4051: ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
4052: ** API always returns a generic error code, [SQLITE_ERROR], following any
4053: ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call
4054: ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
4055: ** specific [error codes] that better describes the error.
4056: ** We admit that this is a goofy design. The problem has been fixed
4057: ** with the "v2" interface. If you prepare all of your SQL statements
4058: ** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead
4059: ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
4060: ** then the more specific [error codes] are returned directly
4061: ** by sqlite3_step(). The use of the "v2" interface is recommended.
4062: */
4063: SQLITE_API int sqlite3_step(sqlite3_stmt*);
4064:
4065: /*
4066: ** CAPI3REF: Number of columns in a result set
4067: ** METHOD: sqlite3_stmt
4068: **
4069: ** ^The sqlite3_data_count(P) interface returns the number of columns in the
4070: ** current row of the result set of [prepared statement] P.
4071: ** ^If prepared statement P does not have results ready to return
4072: ** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of
4073: ** interfaces) then sqlite3_data_count(P) returns 0.
4074: ** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
4075: ** ^The sqlite3_data_count(P) routine returns 0 if the previous call to
4076: ** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P)
4077: ** will return non-zero if previous call to [sqlite3_step](P) returned
4078: ** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum]
4079: ** where it always returns zero since each step of that multi-step
4080: ** pragma returns 0 columns of data.
4081: **
4082: ** See also: [sqlite3_column_count()]
4083: */
4084: SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
4085:
4086: /*
4087: ** CAPI3REF: Fundamental Datatypes
4088: ** KEYWORDS: SQLITE_TEXT
4089: **
4090: ** ^(Every value in SQLite has one of five fundamental datatypes:
4091: **
4092: ** <ul>
4093: ** <li> 64-bit signed integer
4094: ** <li> 64-bit IEEE floating point number
4095: ** <li> string
4096: ** <li> BLOB
4097: ** <li> NULL
4098: ** </ul>)^
4099: **
4100: ** These constants are codes for each of those types.
4101: **
4102: ** Note that the SQLITE_TEXT constant was also used in SQLite version 2
4103: ** for a completely different meaning. Software that links against both
4104: ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
4105: ** SQLITE_TEXT.
4106: */
4107: #define SQLITE_INTEGER 1
4108: #define SQLITE_FLOAT 2
4109: #define SQLITE_BLOB 4
4110: #define SQLITE_NULL 5
4111: #ifdef SQLITE_TEXT
4112: # undef SQLITE_TEXT
4113: #else
4114: # define SQLITE_TEXT 3
4115: #endif
4116: #define SQLITE3_TEXT 3
4117:
4118: /*
4119: ** CAPI3REF: Result Values From A Query
4120: ** KEYWORDS: {column access functions}
4121: ** METHOD: sqlite3_stmt
4122: **
4123: ** ^These routines return information about a single column of the current
4124: ** result row of a query. ^In every case the first argument is a pointer
4125: ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
4126: ** that was returned from [sqlite3_prepare_v2()] or one of its variants)
4127: ** and the second argument is the index of the column for which information
4128: ** should be returned. ^The leftmost column of the result set has the index 0.
4129: ** ^The number of columns in the result can be determined using
4130: ** [sqlite3_column_count()].
4131: **
4132: ** If the SQL statement does not currently point to a valid row, or if the
4133: ** column index is out of range, the result is undefined.
4134: ** These routines may only be called when the most recent call to
4135: ** [sqlite3_step()] has returned [SQLITE_ROW] and neither
4136: ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
4137: ** If any of these routines are called after [sqlite3_reset()] or
4138: ** [sqlite3_finalize()] or after [sqlite3_step()] has returned
4139: ** something other than [SQLITE_ROW], the results are undefined.
4140: ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
4141: ** are called from a different thread while any of these routines
4142: ** are pending, then the results are undefined.
4143: **
4144: ** ^The sqlite3_column_type() routine returns the
4145: ** [SQLITE_INTEGER | datatype code] for the initial data type
4146: ** of the result column. ^The returned value is one of [SQLITE_INTEGER],
4147: ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value
4148: ** returned by sqlite3_column_type() is only meaningful if no type
4149: ** conversions have occurred as described below. After a type conversion,
4150: ** the value returned by sqlite3_column_type() is undefined. Future
4151: ** versions of SQLite may change the behavior of sqlite3_column_type()
4152: ** following a type conversion.
4153: **
4154: ** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
4155: ** routine returns the number of bytes in that BLOB or string.
4156: ** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
4157: ** the string to UTF-8 and then returns the number of bytes.
4158: ** ^If the result is a numeric value then sqlite3_column_bytes() uses
4159: ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
4160: ** the number of bytes in that string.
4161: ** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
4162: **
4163: ** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
4164: ** routine returns the number of bytes in that BLOB or string.
4165: ** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
4166: ** the string to UTF-16 and then returns the number of bytes.
4167: ** ^If the result is a numeric value then sqlite3_column_bytes16() uses
4168: ** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
4169: ** the number of bytes in that string.
4170: ** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
4171: **
4172: ** ^The values returned by [sqlite3_column_bytes()] and
4173: ** [sqlite3_column_bytes16()] do not include the zero terminators at the end
4174: ** of the string. ^For clarity: the values returned by
4175: ** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
4176: ** bytes in the string, not the number of characters.
4177: **
4178: ** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
4179: ** even empty strings, are always zero-terminated. ^The return
4180: ** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
4181: **
4182: ** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an
4183: ** [unprotected sqlite3_value] object. In a multithreaded environment,
4184: ** an unprotected sqlite3_value object may only be used safely with
4185: ** [sqlite3_bind_value()] and [sqlite3_result_value()].
4186: ** If the [unprotected sqlite3_value] object returned by
4187: ** [sqlite3_column_value()] is used in any other way, including calls
4188: ** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
4189: ** or [sqlite3_value_bytes()], the behavior is not threadsafe.
4190: **
4191: ** These routines attempt to convert the value where appropriate. ^For
4192: ** example, if the internal representation is FLOAT and a text result
4193: ** is requested, [sqlite3_snprintf()] is used internally to perform the
4194: ** conversion automatically. ^(The following table details the conversions
4195: ** that are applied:
4196: **
4197: ** <blockquote>
4198: ** <table border="1">
4199: ** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion
4200: **
4201: ** <tr><td> NULL <td> INTEGER <td> Result is 0
4202: ** <tr><td> NULL <td> FLOAT <td> Result is 0.0
4203: ** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer
4204: ** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer
4205: ** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float
4206: ** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer
4207: ** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT
4208: ** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER
4209: ** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float
4210: ** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB
4211: ** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER
4212: ** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL
4213: ** <tr><td> TEXT <td> BLOB <td> No change
4214: ** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER
4215: ** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL
4216: ** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed
4217: ** </table>
4218: ** </blockquote>)^
4219: **
4220: ** Note that when type conversions occur, pointers returned by prior
4221: ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
4222: ** sqlite3_column_text16() may be invalidated.
4223: ** Type conversions and pointer invalidations might occur
4224: ** in the following cases:
4225: **
4226: ** <ul>
4227: ** <li> The initial content is a BLOB and sqlite3_column_text() or
4228: ** sqlite3_column_text16() is called. A zero-terminator might
4229: ** need to be added to the string.</li>
4230: ** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
4231: ** sqlite3_column_text16() is called. The content must be converted
4232: ** to UTF-16.</li>
4233: ** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
4234: ** sqlite3_column_text() is called. The content must be converted
4235: ** to UTF-8.</li>
4236: ** </ul>
4237: **
4238: ** ^Conversions between UTF-16be and UTF-16le are always done in place and do
4239: ** not invalidate a prior pointer, though of course the content of the buffer
4240: ** that the prior pointer references will have been modified. Other kinds
4241: ** of conversion are done in place when it is possible, but sometimes they
4242: ** are not possible and in those cases prior pointers are invalidated.
4243: **
4244: ** The safest policy is to invoke these routines
4245: ** in one of the following ways:
4246: **
4247: ** <ul>
4248: ** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
4249: ** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
4250: ** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
4251: ** </ul>
4252: **
4253: ** In other words, you should call sqlite3_column_text(),
4254: ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
4255: ** into the desired format, then invoke sqlite3_column_bytes() or
4256: ** sqlite3_column_bytes16() to find the size of the result. Do not mix calls
4257: ** to sqlite3_column_text() or sqlite3_column_blob() with calls to
4258: ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
4259: ** with calls to sqlite3_column_bytes().
4260: **
4261: ** ^The pointers returned are valid until a type conversion occurs as
4262: ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
4263: ** [sqlite3_finalize()] is called. ^The memory space used to hold strings
4264: ** and BLOBs is freed automatically. Do <em>not</em> pass the pointers returned
4265: ** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
4266: ** [sqlite3_free()].
4267: **
4268: ** ^(If a memory allocation error occurs during the evaluation of any
4269: ** of these routines, a default value is returned. The default value
4270: ** is either the integer 0, the floating point number 0.0, or a NULL
4271: ** pointer. Subsequent calls to [sqlite3_errcode()] will return
4272: ** [SQLITE_NOMEM].)^
4273: */
4274: SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
4275: SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
4276: SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
4277: SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol);
4278: SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol);
4279: SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
4280: SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
4281: SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
4282: SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol);
4283: SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
4284:
4285: /*
4286: ** CAPI3REF: Destroy A Prepared Statement Object
4287: ** DESTRUCTOR: sqlite3_stmt
4288: **
4289: ** ^The sqlite3_finalize() function is called to delete a [prepared statement].
4290: ** ^If the most recent evaluation of the statement encountered no errors
4291: ** or if the statement is never been evaluated, then sqlite3_finalize() returns
4292: ** SQLITE_OK. ^If the most recent evaluation of statement S failed, then
4293: ** sqlite3_finalize(S) returns the appropriate [error code] or
4294: ** [extended error code].
4295: **
4296: ** ^The sqlite3_finalize(S) routine can be called at any point during
4297: ** the life cycle of [prepared statement] S:
4298: ** before statement S is ever evaluated, after
4299: ** one or more calls to [sqlite3_reset()], or after any call
4300: ** to [sqlite3_step()] regardless of whether or not the statement has
4301: ** completed execution.
4302: **
4303: ** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
4304: **
4305: ** The application must finalize every [prepared statement] in order to avoid
4306: ** resource leaks. It is a grievous error for the application to try to use
4307: ** a prepared statement after it has been finalized. Any use of a prepared
4308: ** statement after it has been finalized can result in undefined and
4309: ** undesirable behavior such as segfaults and heap corruption.
4310: */
4311: SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt);
4312:
4313: /*
4314: ** CAPI3REF: Reset A Prepared Statement Object
4315: ** METHOD: sqlite3_stmt
4316: **
4317: ** The sqlite3_reset() function is called to reset a [prepared statement]
4318: ** object back to its initial state, ready to be re-executed.
4319: ** ^Any SQL statement variables that had values bound to them using
4320: ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
4321: ** Use [sqlite3_clear_bindings()] to reset the bindings.
4322: **
4323: ** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
4324: ** back to the beginning of its program.
4325: **
4326: ** ^If the most recent call to [sqlite3_step(S)] for the
4327: ** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
4328: ** or if [sqlite3_step(S)] has never before been called on S,
4329: ** then [sqlite3_reset(S)] returns [SQLITE_OK].
4330: **
4331: ** ^If the most recent call to [sqlite3_step(S)] for the
4332: ** [prepared statement] S indicated an error, then
4333: ** [sqlite3_reset(S)] returns an appropriate [error code].
4334: **
4335: ** ^The [sqlite3_reset(S)] interface does not change the values
4336: ** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
4337: */
4338: SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt);
4339:
4340: /*
4341: ** CAPI3REF: Create Or Redefine SQL Functions
4342: ** KEYWORDS: {function creation routines}
4343: ** KEYWORDS: {application-defined SQL function}
4344: ** KEYWORDS: {application-defined SQL functions}
4345: ** METHOD: sqlite3
4346: **
4347: ** ^These functions (collectively known as "function creation routines")
4348: ** are used to add SQL functions or aggregates or to redefine the behavior
4349: ** of existing SQL functions or aggregates. The only differences between
4350: ** these routines are the text encoding expected for
4351: ** the second parameter (the name of the function being created)
4352: ** and the presence or absence of a destructor callback for
4353: ** the application data pointer.
4354: **
4355: ** ^The first parameter is the [database connection] to which the SQL
4356: ** function is to be added. ^If an application uses more than one database
4357: ** connection then application-defined SQL functions must be added
4358: ** to each database connection separately.
4359: **
4360: ** ^The second parameter is the name of the SQL function to be created or
4361: ** redefined. ^The length of the name is limited to 255 bytes in a UTF-8
4362: ** representation, exclusive of the zero-terminator. ^Note that the name
4363: ** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
4364: ** ^Any attempt to create a function with a longer name
4365: ** will result in [SQLITE_MISUSE] being returned.
4366: **
4367: ** ^The third parameter (nArg)
4368: ** is the number of arguments that the SQL function or
4369: ** aggregate takes. ^If this parameter is -1, then the SQL function or
4370: ** aggregate may take any number of arguments between 0 and the limit
4371: ** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third
4372: ** parameter is less than -1 or greater than 127 then the behavior is
4373: ** undefined.
4374: **
4375: ** ^The fourth parameter, eTextRep, specifies what
4376: ** [SQLITE_UTF8 | text encoding] this SQL function prefers for
4377: ** its parameters. The application should set this parameter to
4378: ** [SQLITE_UTF16LE] if the function implementation invokes
4379: ** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the
4380: ** implementation invokes [sqlite3_value_text16be()] on an input, or
4381: ** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8]
4382: ** otherwise. ^The same SQL function may be registered multiple times using
4383: ** different preferred text encodings, with different implementations for
4384: ** each encoding.
4385: ** ^When multiple implementations of the same function are available, SQLite
4386: ** will pick the one that involves the least amount of data conversion.
4387: **
4388: ** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC]
4389: ** to signal that the function will always return the same result given
4390: ** the same inputs within a single SQL statement. Most SQL functions are
4391: ** deterministic. The built-in [random()] SQL function is an example of a
4392: ** function that is not deterministic. The SQLite query planner is able to
4393: ** perform additional optimizations on deterministic functions, so use
4394: ** of the [SQLITE_DETERMINISTIC] flag is recommended where possible.
4395: **
4396: ** ^(The fifth parameter is an arbitrary pointer. The implementation of the
4397: ** function can gain access to this pointer using [sqlite3_user_data()].)^
4398: **
4399: ** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are
4400: ** pointers to C-language functions that implement the SQL function or
4401: ** aggregate. ^A scalar SQL function requires an implementation of the xFunc
4402: ** callback only; NULL pointers must be passed as the xStep and xFinal
4403: ** parameters. ^An aggregate SQL function requires an implementation of xStep
4404: ** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
4405: ** SQL function or aggregate, pass NULL pointers for all three function
4406: ** callbacks.
4407: **
4408: ** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL,
4409: ** then it is destructor for the application data pointer.
4410: ** The destructor is invoked when the function is deleted, either by being
4411: ** overloaded or when the database connection closes.)^
4412: ** ^The destructor is also invoked if the call to
4413: ** sqlite3_create_function_v2() fails.
4414: ** ^When the destructor callback of the tenth parameter is invoked, it
4415: ** is passed a single argument which is a copy of the application data
4416: ** pointer which was the fifth parameter to sqlite3_create_function_v2().
4417: **
4418: ** ^It is permitted to register multiple implementations of the same
4419: ** functions with the same name but with either differing numbers of
4420: ** arguments or differing preferred text encodings. ^SQLite will use
4421: ** the implementation that most closely matches the way in which the
4422: ** SQL function is used. ^A function implementation with a non-negative
4423: ** nArg parameter is a better match than a function implementation with
4424: ** a negative nArg. ^A function where the preferred text encoding
4425: ** matches the database encoding is a better
4426: ** match than a function where the encoding is different.
4427: ** ^A function where the encoding difference is between UTF16le and UTF16be
4428: ** is a closer match than a function where the encoding difference is
4429: ** between UTF8 and UTF16.
4430: **
4431: ** ^Built-in functions may be overloaded by new application-defined functions.
4432: **
4433: ** ^An application-defined function is permitted to call other
4434: ** SQLite interfaces. However, such calls must not
4435: ** close the database connection nor finalize or reset the prepared
4436: ** statement in which the function is running.
4437: */
4438: SQLITE_API int sqlite3_create_function(
4439: sqlite3 *db,
4440: const char *zFunctionName,
4441: int nArg,
4442: int eTextRep,
4443: void *pApp,
4444: void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4445: void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4446: void (*xFinal)(sqlite3_context*)
4447: );
4448: SQLITE_API int sqlite3_create_function16(
4449: sqlite3 *db,
4450: const void *zFunctionName,
4451: int nArg,
4452: int eTextRep,
4453: void *pApp,
4454: void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4455: void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4456: void (*xFinal)(sqlite3_context*)
4457: );
4458: SQLITE_API int sqlite3_create_function_v2(
4459: sqlite3 *db,
4460: const char *zFunctionName,
4461: int nArg,
4462: int eTextRep,
4463: void *pApp,
4464: void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4465: void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4466: void (*xFinal)(sqlite3_context*),
4467: void(*xDestroy)(void*)
4468: );
4469:
4470: /*
4471: ** CAPI3REF: Text Encodings
4472: **
4473: ** These constant define integer codes that represent the various
4474: ** text encodings supported by SQLite.
4475: */
4476: #define SQLITE_UTF8 1 /* IMP: R-37514-35566 */
4477: #define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */
4478: #define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */
4479: #define SQLITE_UTF16 4 /* Use native byte order */
4480: #define SQLITE_ANY 5 /* Deprecated */
4481: #define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */
4482:
4483: /*
4484: ** CAPI3REF: Function Flags
4485: **
4486: ** These constants may be ORed together with the
4487: ** [SQLITE_UTF8 | preferred text encoding] as the fourth argument
4488: ** to [sqlite3_create_function()], [sqlite3_create_function16()], or
4489: ** [sqlite3_create_function_v2()].
4490: */
4491: #define SQLITE_DETERMINISTIC 0x800
4492:
4493: /*
4494: ** CAPI3REF: Deprecated Functions
4495: ** DEPRECATED
4496: **
4497: ** These functions are [deprecated]. In order to maintain
4498: ** backwards compatibility with older code, these functions continue
4499: ** to be supported. However, new applications should avoid
4500: ** the use of these functions. To encourage programmers to avoid
4501: ** these functions, we will not explain what they do.
4502: */
4503: #ifndef SQLITE_OMIT_DEPRECATED
4504: SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
4505: SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
4506: SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
4507: SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void);
4508: SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
4509: SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),
4510: void*,sqlite3_int64);
4511: #endif
4512:
4513: /*
4514: ** CAPI3REF: Obtaining SQL Values
4515: ** METHOD: sqlite3_value
4516: **
4517: ** The C-language implementation of SQL functions and aggregates uses
4518: ** this set of interface routines to access the parameter values on
4519: ** the function or aggregate.
4520: **
4521: ** The xFunc (for scalar functions) or xStep (for aggregates) parameters
4522: ** to [sqlite3_create_function()] and [sqlite3_create_function16()]
4523: ** define callbacks that implement the SQL functions and aggregates.
4524: ** The 3rd parameter to these callbacks is an array of pointers to
4525: ** [protected sqlite3_value] objects. There is one [sqlite3_value] object for
4526: ** each parameter to the SQL function. These routines are used to
4527: ** extract values from the [sqlite3_value] objects.
4528: **
4529: ** These routines work only with [protected sqlite3_value] objects.
4530: ** Any attempt to use these routines on an [unprotected sqlite3_value]
4531: ** object results in undefined behavior.
4532: **
4533: ** ^These routines work just like the corresponding [column access functions]
4534: ** except that these routines take a single [protected sqlite3_value] object
4535: ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
4536: **
4537: ** ^The sqlite3_value_text16() interface extracts a UTF-16 string
4538: ** in the native byte-order of the host machine. ^The
4539: ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
4540: ** extract UTF-16 strings as big-endian and little-endian respectively.
4541: **
4542: ** ^(The sqlite3_value_numeric_type() interface attempts to apply
4543: ** numeric affinity to the value. This means that an attempt is
4544: ** made to convert the value to an integer or floating point. If
4545: ** such a conversion is possible without loss of information (in other
4546: ** words, if the value is a string that looks like a number)
4547: ** then the conversion is performed. Otherwise no conversion occurs.
4548: ** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
4549: **
4550: ** Please pay particular attention to the fact that the pointer returned
4551: ** from [sqlite3_value_blob()], [sqlite3_value_text()], or
4552: ** [sqlite3_value_text16()] can be invalidated by a subsequent call to
4553: ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
4554: ** or [sqlite3_value_text16()].
4555: **
4556: ** These routines must be called from the same thread as
4557: ** the SQL function that supplied the [sqlite3_value*] parameters.
4558: */
4559: SQLITE_API const void *sqlite3_value_blob(sqlite3_value*);
4560: SQLITE_API int sqlite3_value_bytes(sqlite3_value*);
4561: SQLITE_API int sqlite3_value_bytes16(sqlite3_value*);
4562: SQLITE_API double sqlite3_value_double(sqlite3_value*);
4563: SQLITE_API int sqlite3_value_int(sqlite3_value*);
4564: SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
4565: SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*);
4566: SQLITE_API const void *sqlite3_value_text16(sqlite3_value*);
4567: SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*);
4568: SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*);
4569: SQLITE_API int sqlite3_value_type(sqlite3_value*);
4570: SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*);
4571:
4572: /*
4573: ** CAPI3REF: Finding The Subtype Of SQL Values
4574: ** METHOD: sqlite3_value
4575: **
4576: ** The sqlite3_value_subtype(V) function returns the subtype for
4577: ** an [application-defined SQL function] argument V. The subtype
4578: ** information can be used to pass a limited amount of context from
4579: ** one SQL function to another. Use the [sqlite3_result_subtype()]
4580: ** routine to set the subtype for the return value of an SQL function.
4581: **
4582: ** SQLite makes no use of subtype itself. It merely passes the subtype
4583: ** from the result of one [application-defined SQL function] into the
4584: ** input of another.
4585: */
4586: SQLITE_API unsigned int sqlite3_value_subtype(sqlite3_value*);
4587:
4588: /*
4589: ** CAPI3REF: Copy And Free SQL Values
4590: ** METHOD: sqlite3_value
4591: **
4592: ** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value]
4593: ** object D and returns a pointer to that copy. ^The [sqlite3_value] returned
4594: ** is a [protected sqlite3_value] object even if the input is not.
4595: ** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a
4596: ** memory allocation fails.
4597: **
4598: ** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object
4599: ** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer
4600: ** then sqlite3_value_free(V) is a harmless no-op.
4601: */
4602: SQLITE_API sqlite3_value *sqlite3_value_dup(const sqlite3_value*);
4603: SQLITE_API void sqlite3_value_free(sqlite3_value*);
4604:
4605: /*
4606: ** CAPI3REF: Obtain Aggregate Function Context
4607: ** METHOD: sqlite3_context
4608: **
4609: ** Implementations of aggregate SQL functions use this
4610: ** routine to allocate memory for storing their state.
4611: **
4612: ** ^The first time the sqlite3_aggregate_context(C,N) routine is called
4613: ** for a particular aggregate function, SQLite
4614: ** allocates N of memory, zeroes out that memory, and returns a pointer
4615: ** to the new memory. ^On second and subsequent calls to
4616: ** sqlite3_aggregate_context() for the same aggregate function instance,
4617: ** the same buffer is returned. Sqlite3_aggregate_context() is normally
4618: ** called once for each invocation of the xStep callback and then one
4619: ** last time when the xFinal callback is invoked. ^(When no rows match
4620: ** an aggregate query, the xStep() callback of the aggregate function
4621: ** implementation is never called and xFinal() is called exactly once.
4622: ** In those cases, sqlite3_aggregate_context() might be called for the
4623: ** first time from within xFinal().)^
4624: **
4625: ** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer
4626: ** when first called if N is less than or equal to zero or if a memory
4627: ** allocate error occurs.
4628: **
4629: ** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
4630: ** determined by the N parameter on first successful call. Changing the
4631: ** value of N in subsequent call to sqlite3_aggregate_context() within
4632: ** the same aggregate function instance will not resize the memory
4633: ** allocation.)^ Within the xFinal callback, it is customary to set
4634: ** N=0 in calls to sqlite3_aggregate_context(C,N) so that no
4635: ** pointless memory allocations occur.
4636: **
4637: ** ^SQLite automatically frees the memory allocated by
4638: ** sqlite3_aggregate_context() when the aggregate query concludes.
4639: **
4640: ** The first parameter must be a copy of the
4641: ** [sqlite3_context | SQL function context] that is the first parameter
4642: ** to the xStep or xFinal callback routine that implements the aggregate
4643: ** function.
4644: **
4645: ** This routine must be called from the same thread in which
4646: ** the aggregate SQL function is running.
4647: */
4648: SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
4649:
4650: /*
4651: ** CAPI3REF: User Data For Functions
4652: ** METHOD: sqlite3_context
4653: **
4654: ** ^The sqlite3_user_data() interface returns a copy of
4655: ** the pointer that was the pUserData parameter (the 5th parameter)
4656: ** of the [sqlite3_create_function()]
4657: ** and [sqlite3_create_function16()] routines that originally
4658: ** registered the application defined function.
4659: **
4660: ** This routine must be called from the same thread in which
4661: ** the application-defined function is running.
4662: */
4663: SQLITE_API void *sqlite3_user_data(sqlite3_context*);
4664:
4665: /*
4666: ** CAPI3REF: Database Connection For Functions
4667: ** METHOD: sqlite3_context
4668: **
4669: ** ^The sqlite3_context_db_handle() interface returns a copy of
4670: ** the pointer to the [database connection] (the 1st parameter)
4671: ** of the [sqlite3_create_function()]
4672: ** and [sqlite3_create_function16()] routines that originally
4673: ** registered the application defined function.
4674: */
4675: SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
4676:
4677: /*
4678: ** CAPI3REF: Function Auxiliary Data
4679: ** METHOD: sqlite3_context
4680: **
4681: ** These functions may be used by (non-aggregate) SQL functions to
4682: ** associate metadata with argument values. If the same value is passed to
4683: ** multiple invocations of the same SQL function during query execution, under
4684: ** some circumstances the associated metadata may be preserved. An example
4685: ** of where this might be useful is in a regular-expression matching
4686: ** function. The compiled version of the regular expression can be stored as
4687: ** metadata associated with the pattern string.
4688: ** Then as long as the pattern string remains the same,
4689: ** the compiled regular expression can be reused on multiple
4690: ** invocations of the same function.
4691: **
4692: ** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata
4693: ** associated by the sqlite3_set_auxdata() function with the Nth argument
4694: ** value to the application-defined function. ^If there is no metadata
4695: ** associated with the function argument, this sqlite3_get_auxdata() interface
4696: ** returns a NULL pointer.
4697: **
4698: ** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th
4699: ** argument of the application-defined function. ^Subsequent
4700: ** calls to sqlite3_get_auxdata(C,N) return P from the most recent
4701: ** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or
4702: ** NULL if the metadata has been discarded.
4703: ** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL,
4704: ** SQLite will invoke the destructor function X with parameter P exactly
4705: ** once, when the metadata is discarded.
4706: ** SQLite is free to discard the metadata at any time, including: <ul>
4707: ** <li> ^(when the corresponding function parameter changes)^, or
4708: ** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the
4709: ** SQL statement)^, or
4710: ** <li> ^(when sqlite3_set_auxdata() is invoked again on the same
4711: ** parameter)^, or
4712: ** <li> ^(during the original sqlite3_set_auxdata() call when a memory
4713: ** allocation error occurs.)^ </ul>
4714: **
4715: ** Note the last bullet in particular. The destructor X in
4716: ** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the
4717: ** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata()
4718: ** should be called near the end of the function implementation and the
4719: ** function implementation should not make any use of P after
4720: ** sqlite3_set_auxdata() has been called.
4721: **
4722: ** ^(In practice, metadata is preserved between function calls for
4723: ** function parameters that are compile-time constants, including literal
4724: ** values and [parameters] and expressions composed from the same.)^
4725: **
4726: ** These routines must be called from the same thread in which
4727: ** the SQL function is running.
4728: */
4729: SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N);
4730: SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
4731:
4732:
4733: /*
4734: ** CAPI3REF: Constants Defining Special Destructor Behavior
4735: **
4736: ** These are special values for the destructor that is passed in as the
4737: ** final argument to routines like [sqlite3_result_blob()]. ^If the destructor
4738: ** argument is SQLITE_STATIC, it means that the content pointer is constant
4739: ** and will never change. It does not need to be destroyed. ^The
4740: ** SQLITE_TRANSIENT value means that the content will likely change in
4741: ** the near future and that SQLite should make its own private copy of
4742: ** the content before returning.
4743: **
4744: ** The typedef is necessary to work around problems in certain
4745: ** C++ compilers.
4746: */
4747: typedef void (*sqlite3_destructor_type)(void*);
4748: #define SQLITE_STATIC ((sqlite3_destructor_type)0)
4749: #define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1)
4750:
4751: /*
4752: ** CAPI3REF: Setting The Result Of An SQL Function
4753: ** METHOD: sqlite3_context
4754: **
4755: ** These routines are used by the xFunc or xFinal callbacks that
4756: ** implement SQL functions and aggregates. See
4757: ** [sqlite3_create_function()] and [sqlite3_create_function16()]
4758: ** for additional information.
4759: **
4760: ** These functions work very much like the [parameter binding] family of
4761: ** functions used to bind values to host parameters in prepared statements.
4762: ** Refer to the [SQL parameter] documentation for additional information.
4763: **
4764: ** ^The sqlite3_result_blob() interface sets the result from
4765: ** an application-defined function to be the BLOB whose content is pointed
4766: ** to by the second parameter and which is N bytes long where N is the
4767: ** third parameter.
4768: **
4769: ** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N)
4770: ** interfaces set the result of the application-defined function to be
4771: ** a BLOB containing all zero bytes and N bytes in size.
4772: **
4773: ** ^The sqlite3_result_double() interface sets the result from
4774: ** an application-defined function to be a floating point value specified
4775: ** by its 2nd argument.
4776: **
4777: ** ^The sqlite3_result_error() and sqlite3_result_error16() functions
4778: ** cause the implemented SQL function to throw an exception.
4779: ** ^SQLite uses the string pointed to by the
4780: ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
4781: ** as the text of an error message. ^SQLite interprets the error
4782: ** message string from sqlite3_result_error() as UTF-8. ^SQLite
4783: ** interprets the string from sqlite3_result_error16() as UTF-16 in native
4784: ** byte order. ^If the third parameter to sqlite3_result_error()
4785: ** or sqlite3_result_error16() is negative then SQLite takes as the error
4786: ** message all text up through the first zero character.
4787: ** ^If the third parameter to sqlite3_result_error() or
4788: ** sqlite3_result_error16() is non-negative then SQLite takes that many
4789: ** bytes (not characters) from the 2nd parameter as the error message.
4790: ** ^The sqlite3_result_error() and sqlite3_result_error16()
4791: ** routines make a private copy of the error message text before
4792: ** they return. Hence, the calling function can deallocate or
4793: ** modify the text after they return without harm.
4794: ** ^The sqlite3_result_error_code() function changes the error code
4795: ** returned by SQLite as a result of an error in a function. ^By default,
4796: ** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error()
4797: ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
4798: **
4799: ** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an
4800: ** error indicating that a string or BLOB is too long to represent.
4801: **
4802: ** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an
4803: ** error indicating that a memory allocation failed.
4804: **
4805: ** ^The sqlite3_result_int() interface sets the return value
4806: ** of the application-defined function to be the 32-bit signed integer
4807: ** value given in the 2nd argument.
4808: ** ^The sqlite3_result_int64() interface sets the return value
4809: ** of the application-defined function to be the 64-bit signed integer
4810: ** value given in the 2nd argument.
4811: **
4812: ** ^The sqlite3_result_null() interface sets the return value
4813: ** of the application-defined function to be NULL.
4814: **
4815: ** ^The sqlite3_result_text(), sqlite3_result_text16(),
4816: ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
4817: ** set the return value of the application-defined function to be
4818: ** a text string which is represented as UTF-8, UTF-16 native byte order,
4819: ** UTF-16 little endian, or UTF-16 big endian, respectively.
4820: ** ^The sqlite3_result_text64() interface sets the return value of an
4821: ** application-defined function to be a text string in an encoding
4822: ** specified by the fifth (and last) parameter, which must be one
4823: ** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE].
4824: ** ^SQLite takes the text result from the application from
4825: ** the 2nd parameter of the sqlite3_result_text* interfaces.
4826: ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
4827: ** is negative, then SQLite takes result text from the 2nd parameter
4828: ** through the first zero character.
4829: ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
4830: ** is non-negative, then as many bytes (not characters) of the text
4831: ** pointed to by the 2nd parameter are taken as the application-defined
4832: ** function result. If the 3rd parameter is non-negative, then it
4833: ** must be the byte offset into the string where the NUL terminator would
4834: ** appear if the string where NUL terminated. If any NUL characters occur
4835: ** in the string at a byte offset that is less than the value of the 3rd
4836: ** parameter, then the resulting string will contain embedded NULs and the
4837: ** result of expressions operating on strings with embedded NULs is undefined.
4838: ** ^If the 4th parameter to the sqlite3_result_text* interfaces
4839: ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
4840: ** function as the destructor on the text or BLOB result when it has
4841: ** finished using that result.
4842: ** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
4843: ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
4844: ** assumes that the text or BLOB result is in constant space and does not
4845: ** copy the content of the parameter nor call a destructor on the content
4846: ** when it has finished using that result.
4847: ** ^If the 4th parameter to the sqlite3_result_text* interfaces
4848: ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
4849: ** then SQLite makes a copy of the result into space obtained from
4850: ** from [sqlite3_malloc()] before it returns.
4851: **
4852: ** ^The sqlite3_result_value() interface sets the result of
4853: ** the application-defined function to be a copy of the
4854: ** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The
4855: ** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
4856: ** so that the [sqlite3_value] specified in the parameter may change or
4857: ** be deallocated after sqlite3_result_value() returns without harm.
4858: ** ^A [protected sqlite3_value] object may always be used where an
4859: ** [unprotected sqlite3_value] object is required, so either
4860: ** kind of [sqlite3_value] object can be used with this interface.
4861: **
4862: ** If these routines are called from within the different thread
4863: ** than the one containing the application-defined function that received
4864: ** the [sqlite3_context] pointer, the results are undefined.
4865: */
4866: SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
4867: SQLITE_API void sqlite3_result_blob64(sqlite3_context*,const void*,
4868: sqlite3_uint64,void(*)(void*));
4869: SQLITE_API void sqlite3_result_double(sqlite3_context*, double);
4870: SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int);
4871: SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int);
4872: SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*);
4873: SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*);
4874: SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int);
4875: SQLITE_API void sqlite3_result_int(sqlite3_context*, int);
4876: SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
4877: SQLITE_API void sqlite3_result_null(sqlite3_context*);
4878: SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
4879: SQLITE_API void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64,
4880: void(*)(void*), unsigned char encoding);
4881: SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
4882: SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
4883: SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
4884: SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
4885: SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n);
4886: SQLITE_API int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n);
4887:
4888:
4889: /*
4890: ** CAPI3REF: Setting The Subtype Of An SQL Function
4891: ** METHOD: sqlite3_context
4892: **
4893: ** The sqlite3_result_subtype(C,T) function causes the subtype of
4894: ** the result from the [application-defined SQL function] with
4895: ** [sqlite3_context] C to be the value T. Only the lower 8 bits
4896: ** of the subtype T are preserved in current versions of SQLite;
4897: ** higher order bits are discarded.
4898: ** The number of subtype bytes preserved by SQLite might increase
4899: ** in future releases of SQLite.
4900: */
4901: SQLITE_API void sqlite3_result_subtype(sqlite3_context*,unsigned int);
4902:
4903: /*
4904: ** CAPI3REF: Define New Collating Sequences
4905: ** METHOD: sqlite3
4906: **
4907: ** ^These functions add, remove, or modify a [collation] associated
4908: ** with the [database connection] specified as the first argument.
4909: **
4910: ** ^The name of the collation is a UTF-8 string
4911: ** for sqlite3_create_collation() and sqlite3_create_collation_v2()
4912: ** and a UTF-16 string in native byte order for sqlite3_create_collation16().
4913: ** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
4914: ** considered to be the same name.
4915: **
4916: ** ^(The third argument (eTextRep) must be one of the constants:
4917: ** <ul>
4918: ** <li> [SQLITE_UTF8],
4919: ** <li> [SQLITE_UTF16LE],
4920: ** <li> [SQLITE_UTF16BE],
4921: ** <li> [SQLITE_UTF16], or
4922: ** <li> [SQLITE_UTF16_ALIGNED].
4923: ** </ul>)^
4924: ** ^The eTextRep argument determines the encoding of strings passed
4925: ** to the collating function callback, xCallback.
4926: ** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
4927: ** force strings to be UTF16 with native byte order.
4928: ** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
4929: ** on an even byte address.
4930: **
4931: ** ^The fourth argument, pArg, is an application data pointer that is passed
4932: ** through as the first argument to the collating function callback.
4933: **
4934: ** ^The fifth argument, xCallback, is a pointer to the collating function.
4935: ** ^Multiple collating functions can be registered using the same name but
4936: ** with different eTextRep parameters and SQLite will use whichever
4937: ** function requires the least amount of data transformation.
4938: ** ^If the xCallback argument is NULL then the collating function is
4939: ** deleted. ^When all collating functions having the same name are deleted,
4940: ** that collation is no longer usable.
4941: **
4942: ** ^The collating function callback is invoked with a copy of the pArg
4943: ** application data pointer and with two strings in the encoding specified
4944: ** by the eTextRep argument. The collating function must return an
4945: ** integer that is negative, zero, or positive
4946: ** if the first string is less than, equal to, or greater than the second,
4947: ** respectively. A collating function must always return the same answer
4948: ** given the same inputs. If two or more collating functions are registered
4949: ** to the same collation name (using different eTextRep values) then all
4950: ** must give an equivalent answer when invoked with equivalent strings.
4951: ** The collating function must obey the following properties for all
4952: ** strings A, B, and C:
4953: **
4954: ** <ol>
4955: ** <li> If A==B then B==A.
4956: ** <li> If A==B and B==C then A==C.
4957: ** <li> If A<B THEN B>A.
4958: ** <li> If A<B and B<C then A<C.
4959: ** </ol>
4960: **
4961: ** If a collating function fails any of the above constraints and that
4962: ** collating function is registered and used, then the behavior of SQLite
4963: ** is undefined.
4964: **
4965: ** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
4966: ** with the addition that the xDestroy callback is invoked on pArg when
4967: ** the collating function is deleted.
4968: ** ^Collating functions are deleted when they are overridden by later
4969: ** calls to the collation creation functions or when the
4970: ** [database connection] is closed using [sqlite3_close()].
4971: **
4972: ** ^The xDestroy callback is <u>not</u> called if the
4973: ** sqlite3_create_collation_v2() function fails. Applications that invoke
4974: ** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
4975: ** check the return code and dispose of the application data pointer
4976: ** themselves rather than expecting SQLite to deal with it for them.
4977: ** This is different from every other SQLite interface. The inconsistency
4978: ** is unfortunate but cannot be changed without breaking backwards
4979: ** compatibility.
4980: **
4981: ** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
4982: */
4983: SQLITE_API int sqlite3_create_collation(
4984: sqlite3*,
4985: const char *zName,
4986: int eTextRep,
4987: void *pArg,
4988: int(*xCompare)(void*,int,const void*,int,const void*)
4989: );
4990: SQLITE_API int sqlite3_create_collation_v2(
4991: sqlite3*,
4992: const char *zName,
4993: int eTextRep,
4994: void *pArg,
4995: int(*xCompare)(void*,int,const void*,int,const void*),
4996: void(*xDestroy)(void*)
4997: );
4998: SQLITE_API int sqlite3_create_collation16(
4999: sqlite3*,
5000: const void *zName,
5001: int eTextRep,
5002: void *pArg,
5003: int(*xCompare)(void*,int,const void*,int,const void*)
5004: );
5005:
5006: /*
5007: ** CAPI3REF: Collation Needed Callbacks
5008: ** METHOD: sqlite3
5009: **
5010: ** ^To avoid having to register all collation sequences before a database
5011: ** can be used, a single callback function may be registered with the
5012: ** [database connection] to be invoked whenever an undefined collation
5013: ** sequence is required.
5014: **
5015: ** ^If the function is registered using the sqlite3_collation_needed() API,
5016: ** then it is passed the names of undefined collation sequences as strings
5017: ** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
5018: ** the names are passed as UTF-16 in machine native byte order.
5019: ** ^A call to either function replaces the existing collation-needed callback.
5020: **
5021: ** ^(When the callback is invoked, the first argument passed is a copy
5022: ** of the second argument to sqlite3_collation_needed() or
5023: ** sqlite3_collation_needed16(). The second argument is the database
5024: ** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
5025: ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
5026: ** sequence function required. The fourth parameter is the name of the
5027: ** required collation sequence.)^
5028: **
5029: ** The callback function should register the desired collation using
5030: ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
5031: ** [sqlite3_create_collation_v2()].
5032: */
5033: SQLITE_API int sqlite3_collation_needed(
5034: sqlite3*,
5035: void*,
5036: void(*)(void*,sqlite3*,int eTextRep,const char*)
5037: );
5038: SQLITE_API int sqlite3_collation_needed16(
5039: sqlite3*,
5040: void*,
5041: void(*)(void*,sqlite3*,int eTextRep,const void*)
5042: );
5043:
5044: #ifdef SQLITE_HAS_CODEC
5045: /*
5046: ** Specify the key for an encrypted database. This routine should be
5047: ** called right after sqlite3_open().
5048: **
5049: ** The code to implement this API is not available in the public release
5050: ** of SQLite.
5051: */
5052: SQLITE_API int sqlite3_key(
5053: sqlite3 *db, /* Database to be rekeyed */
5054: const void *pKey, int nKey /* The key */
5055: );
5056: SQLITE_API int sqlite3_key_v2(
5057: sqlite3 *db, /* Database to be rekeyed */
5058: const char *zDbName, /* Name of the database */
5059: const void *pKey, int nKey /* The key */
5060: );
5061:
5062: /*
5063: ** Change the key on an open database. If the current database is not
5064: ** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the
5065: ** database is decrypted.
5066: **
5067: ** The code to implement this API is not available in the public release
5068: ** of SQLite.
5069: */
5070: SQLITE_API int sqlite3_rekey(
5071: sqlite3 *db, /* Database to be rekeyed */
5072: const void *pKey, int nKey /* The new key */
5073: );
5074: SQLITE_API int sqlite3_rekey_v2(
5075: sqlite3 *db, /* Database to be rekeyed */
5076: const char *zDbName, /* Name of the database */
5077: const void *pKey, int nKey /* The new key */
5078: );
5079:
5080: /*
5081: ** Specify the activation key for a SEE database. Unless
5082: ** activated, none of the SEE routines will work.
5083: */
5084: SQLITE_API void sqlite3_activate_see(
5085: const char *zPassPhrase /* Activation phrase */
5086: );
5087: #endif
5088:
5089: #ifdef SQLITE_ENABLE_CEROD
5090: /*
5091: ** Specify the activation key for a CEROD database. Unless
5092: ** activated, none of the CEROD routines will work.
5093: */
5094: SQLITE_API void sqlite3_activate_cerod(
5095: const char *zPassPhrase /* Activation phrase */
5096: );
5097: #endif
5098:
5099: /*
5100: ** CAPI3REF: Suspend Execution For A Short Time
5101: **
5102: ** The sqlite3_sleep() function causes the current thread to suspend execution
5103: ** for at least a number of milliseconds specified in its parameter.
5104: **
5105: ** If the operating system does not support sleep requests with
5106: ** millisecond time resolution, then the time will be rounded up to
5107: ** the nearest second. The number of milliseconds of sleep actually
5108: ** requested from the operating system is returned.
5109: **
5110: ** ^SQLite implements this interface by calling the xSleep()
5111: ** method of the default [sqlite3_vfs] object. If the xSleep() method
5112: ** of the default VFS is not implemented correctly, or not implemented at
5113: ** all, then the behavior of sqlite3_sleep() may deviate from the description
5114: ** in the previous paragraphs.
5115: */
5116: SQLITE_API int sqlite3_sleep(int);
5117:
5118: /*
5119: ** CAPI3REF: Name Of The Folder Holding Temporary Files
5120: **
5121: ** ^(If this global variable is made to point to a string which is
5122: ** the name of a folder (a.k.a. directory), then all temporary files
5123: ** created by SQLite when using a built-in [sqlite3_vfs | VFS]
5124: ** will be placed in that directory.)^ ^If this variable
5125: ** is a NULL pointer, then SQLite performs a search for an appropriate
5126: ** temporary file directory.
5127: **
5128: ** Applications are strongly discouraged from using this global variable.
5129: ** It is required to set a temporary folder on Windows Runtime (WinRT).
5130: ** But for all other platforms, it is highly recommended that applications
5131: ** neither read nor write this variable. This global variable is a relic
5132: ** that exists for backwards compatibility of legacy applications and should
5133: ** be avoided in new projects.
5134: **
5135: ** It is not safe to read or modify this variable in more than one
5136: ** thread at a time. It is not safe to read or modify this variable
5137: ** if a [database connection] is being used at the same time in a separate
5138: ** thread.
5139: ** It is intended that this variable be set once
5140: ** as part of process initialization and before any SQLite interface
5141: ** routines have been called and that this variable remain unchanged
5142: ** thereafter.
5143: **
5144: ** ^The [temp_store_directory pragma] may modify this variable and cause
5145: ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,
5146: ** the [temp_store_directory pragma] always assumes that any string
5147: ** that this variable points to is held in memory obtained from
5148: ** [sqlite3_malloc] and the pragma may attempt to free that memory
5149: ** using [sqlite3_free].
5150: ** Hence, if this variable is modified directly, either it should be
5151: ** made NULL or made to point to memory obtained from [sqlite3_malloc]
5152: ** or else the use of the [temp_store_directory pragma] should be avoided.
5153: ** Except when requested by the [temp_store_directory pragma], SQLite
5154: ** does not free the memory that sqlite3_temp_directory points to. If
5155: ** the application wants that memory to be freed, it must do
5156: ** so itself, taking care to only do so after all [database connection]
5157: ** objects have been destroyed.
5158: **
5159: ** <b>Note to Windows Runtime users:</b> The temporary directory must be set
5160: ** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various
5161: ** features that require the use of temporary files may fail. Here is an
5162: ** example of how to do this using C++ with the Windows Runtime:
5163: **
5164: ** <blockquote><pre>
5165: ** LPCWSTR zPath = Windows::Storage::ApplicationData::Current->
5166: ** TemporaryFolder->Path->Data();
5167: ** char zPathBuf[MAX_PATH + 1];
5168: ** memset(zPathBuf, 0, sizeof(zPathBuf));
5169: ** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),
5170: ** NULL, NULL);
5171: ** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);
5172: ** </pre></blockquote>
5173: */
5174: SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory;
5175:
5176: /*
5177: ** CAPI3REF: Name Of The Folder Holding Database Files
5178: **
5179: ** ^(If this global variable is made to point to a string which is
5180: ** the name of a folder (a.k.a. directory), then all database files
5181: ** specified with a relative pathname and created or accessed by
5182: ** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed
5183: ** to be relative to that directory.)^ ^If this variable is a NULL
5184: ** pointer, then SQLite assumes that all database files specified
5185: ** with a relative pathname are relative to the current directory
5186: ** for the process. Only the windows VFS makes use of this global
5187: ** variable; it is ignored by the unix VFS.
5188: **
5189: ** Changing the value of this variable while a database connection is
5190: ** open can result in a corrupt database.
5191: **
5192: ** It is not safe to read or modify this variable in more than one
5193: ** thread at a time. It is not safe to read or modify this variable
5194: ** if a [database connection] is being used at the same time in a separate
5195: ** thread.
5196: ** It is intended that this variable be set once
5197: ** as part of process initialization and before any SQLite interface
5198: ** routines have been called and that this variable remain unchanged
5199: ** thereafter.
5200: **
5201: ** ^The [data_store_directory pragma] may modify this variable and cause
5202: ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,
5203: ** the [data_store_directory pragma] always assumes that any string
5204: ** that this variable points to is held in memory obtained from
5205: ** [sqlite3_malloc] and the pragma may attempt to free that memory
5206: ** using [sqlite3_free].
5207: ** Hence, if this variable is modified directly, either it should be
5208: ** made NULL or made to point to memory obtained from [sqlite3_malloc]
5209: ** or else the use of the [data_store_directory pragma] should be avoided.
5210: */
5211: SQLITE_API SQLITE_EXTERN char *sqlite3_data_directory;
5212:
5213: /*
5214: ** CAPI3REF: Test For Auto-Commit Mode
5215: ** KEYWORDS: {autocommit mode}
5216: ** METHOD: sqlite3
5217: **
5218: ** ^The sqlite3_get_autocommit() interface returns non-zero or
5219: ** zero if the given database connection is or is not in autocommit mode,
5220: ** respectively. ^Autocommit mode is on by default.
5221: ** ^Autocommit mode is disabled by a [BEGIN] statement.
5222: ** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
5223: **
5224: ** If certain kinds of errors occur on a statement within a multi-statement
5225: ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
5226: ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
5227: ** transaction might be rolled back automatically. The only way to
5228: ** find out whether SQLite automatically rolled back the transaction after
5229: ** an error is to use this function.
5230: **
5231: ** If another thread changes the autocommit status of the database
5232: ** connection while this routine is running, then the return value
5233: ** is undefined.
5234: */
5235: SQLITE_API int sqlite3_get_autocommit(sqlite3*);
5236:
5237: /*
5238: ** CAPI3REF: Find The Database Handle Of A Prepared Statement
5239: ** METHOD: sqlite3_stmt
5240: **
5241: ** ^The sqlite3_db_handle interface returns the [database connection] handle
5242: ** to which a [prepared statement] belongs. ^The [database connection]
5243: ** returned by sqlite3_db_handle is the same [database connection]
5244: ** that was the first argument
5245: ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
5246: ** create the statement in the first place.
5247: */
5248: SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
5249:
5250: /*
5251: ** CAPI3REF: Return The Filename For A Database Connection
5252: ** METHOD: sqlite3
5253: **
5254: ** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename
5255: ** associated with database N of connection D. ^The main database file
5256: ** has the name "main". If there is no attached database N on the database
5257: ** connection D, or if database N is a temporary or in-memory database, then
5258: ** a NULL pointer is returned.
5259: **
5260: ** ^The filename returned by this function is the output of the
5261: ** xFullPathname method of the [VFS]. ^In other words, the filename
5262: ** will be an absolute pathname, even if the filename used
5263: ** to open the database originally was a URI or relative pathname.
5264: */
5265: SQLITE_API const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName);
5266:
5267: /*
5268: ** CAPI3REF: Determine if a database is read-only
5269: ** METHOD: sqlite3
5270: **
5271: ** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N
5272: ** of connection D is read-only, 0 if it is read/write, or -1 if N is not
5273: ** the name of a database on connection D.
5274: */
5275: SQLITE_API int sqlite3_db_readonly(sqlite3 *db, const char *zDbName);
5276:
5277: /*
5278: ** CAPI3REF: Find the next prepared statement
5279: ** METHOD: sqlite3
5280: **
5281: ** ^This interface returns a pointer to the next [prepared statement] after
5282: ** pStmt associated with the [database connection] pDb. ^If pStmt is NULL
5283: ** then this interface returns a pointer to the first prepared statement
5284: ** associated with the database connection pDb. ^If no prepared statement
5285: ** satisfies the conditions of this routine, it returns NULL.
5286: **
5287: ** The [database connection] pointer D in a call to
5288: ** [sqlite3_next_stmt(D,S)] must refer to an open database
5289: ** connection and in particular must not be a NULL pointer.
5290: */
5291: SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
5292:
5293: /*
5294: ** CAPI3REF: Commit And Rollback Notification Callbacks
5295: ** METHOD: sqlite3
5296: **
5297: ** ^The sqlite3_commit_hook() interface registers a callback
5298: ** function to be invoked whenever a transaction is [COMMIT | committed].
5299: ** ^Any callback set by a previous call to sqlite3_commit_hook()
5300: ** for the same database connection is overridden.
5301: ** ^The sqlite3_rollback_hook() interface registers a callback
5302: ** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
5303: ** ^Any callback set by a previous call to sqlite3_rollback_hook()
5304: ** for the same database connection is overridden.
5305: ** ^The pArg argument is passed through to the callback.
5306: ** ^If the callback on a commit hook function returns non-zero,
5307: ** then the commit is converted into a rollback.
5308: **
5309: ** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
5310: ** return the P argument from the previous call of the same function
5311: ** on the same [database connection] D, or NULL for
5312: ** the first call for each function on D.
5313: **
5314: ** The commit and rollback hook callbacks are not reentrant.
5315: ** The callback implementation must not do anything that will modify
5316: ** the database connection that invoked the callback. Any actions
5317: ** to modify the database connection must be deferred until after the
5318: ** completion of the [sqlite3_step()] call that triggered the commit
5319: ** or rollback hook in the first place.
5320: ** Note that running any other SQL statements, including SELECT statements,
5321: ** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
5322: ** the database connections for the meaning of "modify" in this paragraph.
5323: **
5324: ** ^Registering a NULL function disables the callback.
5325: **
5326: ** ^When the commit hook callback routine returns zero, the [COMMIT]
5327: ** operation is allowed to continue normally. ^If the commit hook
5328: ** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
5329: ** ^The rollback hook is invoked on a rollback that results from a commit
5330: ** hook returning non-zero, just as it would be with any other rollback.
5331: **
5332: ** ^For the purposes of this API, a transaction is said to have been
5333: ** rolled back if an explicit "ROLLBACK" statement is executed, or
5334: ** an error or constraint causes an implicit rollback to occur.
5335: ** ^The rollback callback is not invoked if a transaction is
5336: ** automatically rolled back because the database connection is closed.
5337: **
5338: ** See also the [sqlite3_update_hook()] interface.
5339: */
5340: SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
5341: SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
5342:
5343: /*
5344: ** CAPI3REF: Data Change Notification Callbacks
5345: ** METHOD: sqlite3
5346: **
5347: ** ^The sqlite3_update_hook() interface registers a callback function
5348: ** with the [database connection] identified by the first argument
5349: ** to be invoked whenever a row is updated, inserted or deleted in
5350: ** a [rowid table].
5351: ** ^Any callback set by a previous call to this function
5352: ** for the same database connection is overridden.
5353: **
5354: ** ^The second argument is a pointer to the function to invoke when a
5355: ** row is updated, inserted or deleted in a rowid table.
5356: ** ^The first argument to the callback is a copy of the third argument
5357: ** to sqlite3_update_hook().
5358: ** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
5359: ** or [SQLITE_UPDATE], depending on the operation that caused the callback
5360: ** to be invoked.
5361: ** ^The third and fourth arguments to the callback contain pointers to the
5362: ** database and table name containing the affected row.
5363: ** ^The final callback parameter is the [rowid] of the row.
5364: ** ^In the case of an update, this is the [rowid] after the update takes place.
5365: **
5366: ** ^(The update hook is not invoked when internal system tables are
5367: ** modified (i.e. sqlite_master and sqlite_sequence).)^
5368: ** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified.
5369: **
5370: ** ^In the current implementation, the update hook
5371: ** is not invoked when duplication rows are deleted because of an
5372: ** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook
5373: ** invoked when rows are deleted using the [truncate optimization].
5374: ** The exceptions defined in this paragraph might change in a future
5375: ** release of SQLite.
5376: **
5377: ** The update hook implementation must not do anything that will modify
5378: ** the database connection that invoked the update hook. Any actions
5379: ** to modify the database connection must be deferred until after the
5380: ** completion of the [sqlite3_step()] call that triggered the update hook.
5381: ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
5382: ** database connections for the meaning of "modify" in this paragraph.
5383: **
5384: ** ^The sqlite3_update_hook(D,C,P) function
5385: ** returns the P argument from the previous call
5386: ** on the same [database connection] D, or NULL for
5387: ** the first call on D.
5388: **
5389: ** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()],
5390: ** and [sqlite3_preupdate_hook()] interfaces.
5391: */
5392: SQLITE_API void *sqlite3_update_hook(
5393: sqlite3*,
5394: void(*)(void *,int ,char const *,char const *,sqlite3_int64),
5395: void*
5396: );
5397:
5398: /*
5399: ** CAPI3REF: Enable Or Disable Shared Pager Cache
5400: **
5401: ** ^(This routine enables or disables the sharing of the database cache
5402: ** and schema data structures between [database connection | connections]
5403: ** to the same database. Sharing is enabled if the argument is true
5404: ** and disabled if the argument is false.)^
5405: **
5406: ** ^Cache sharing is enabled and disabled for an entire process.
5407: ** This is a change as of SQLite version 3.5.0. In prior versions of SQLite,
5408: ** sharing was enabled or disabled for each thread separately.
5409: **
5410: ** ^(The cache sharing mode set by this interface effects all subsequent
5411: ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
5412: ** Existing database connections continue use the sharing mode
5413: ** that was in effect at the time they were opened.)^
5414: **
5415: ** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
5416: ** successfully. An [error code] is returned otherwise.)^
5417: **
5418: ** ^Shared cache is disabled by default. But this might change in
5419: ** future releases of SQLite. Applications that care about shared
5420: ** cache setting should set it explicitly.
5421: **
5422: ** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0
5423: ** and will always return SQLITE_MISUSE. On those systems,
5424: ** shared cache mode should be enabled per-database connection via
5425: ** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE].
5426: **
5427: ** This interface is threadsafe on processors where writing a
5428: ** 32-bit integer is atomic.
5429: **
5430: ** See Also: [SQLite Shared-Cache Mode]
5431: */
5432: SQLITE_API int sqlite3_enable_shared_cache(int);
5433:
5434: /*
5435: ** CAPI3REF: Attempt To Free Heap Memory
5436: **
5437: ** ^The sqlite3_release_memory() interface attempts to free N bytes
5438: ** of heap memory by deallocating non-essential memory allocations
5439: ** held by the database library. Memory used to cache database
5440: ** pages to improve performance is an example of non-essential memory.
5441: ** ^sqlite3_release_memory() returns the number of bytes actually freed,
5442: ** which might be more or less than the amount requested.
5443: ** ^The sqlite3_release_memory() routine is a no-op returning zero
5444: ** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
5445: **
5446: ** See also: [sqlite3_db_release_memory()]
5447: */
5448: SQLITE_API int sqlite3_release_memory(int);
5449:
5450: /*
5451: ** CAPI3REF: Free Memory Used By A Database Connection
5452: ** METHOD: sqlite3
5453: **
5454: ** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap
5455: ** memory as possible from database connection D. Unlike the
5456: ** [sqlite3_release_memory()] interface, this interface is in effect even
5457: ** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
5458: ** omitted.
5459: **
5460: ** See also: [sqlite3_release_memory()]
5461: */
5462: SQLITE_API int sqlite3_db_release_memory(sqlite3*);
5463:
5464: /*
5465: ** CAPI3REF: Impose A Limit On Heap Size
5466: **
5467: ** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
5468: ** soft limit on the amount of heap memory that may be allocated by SQLite.
5469: ** ^SQLite strives to keep heap memory utilization below the soft heap
5470: ** limit by reducing the number of pages held in the page cache
5471: ** as heap memory usages approaches the limit.
5472: ** ^The soft heap limit is "soft" because even though SQLite strives to stay
5473: ** below the limit, it will exceed the limit rather than generate
5474: ** an [SQLITE_NOMEM] error. In other words, the soft heap limit
5475: ** is advisory only.
5476: **
5477: ** ^The return value from sqlite3_soft_heap_limit64() is the size of
5478: ** the soft heap limit prior to the call, or negative in the case of an
5479: ** error. ^If the argument N is negative
5480: ** then no change is made to the soft heap limit. Hence, the current
5481: ** size of the soft heap limit can be determined by invoking
5482: ** sqlite3_soft_heap_limit64() with a negative argument.
5483: **
5484: ** ^If the argument N is zero then the soft heap limit is disabled.
5485: **
5486: ** ^(The soft heap limit is not enforced in the current implementation
5487: ** if one or more of following conditions are true:
5488: **
5489: ** <ul>
5490: ** <li> The soft heap limit is set to zero.
5491: ** <li> Memory accounting is disabled using a combination of the
5492: ** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
5493: ** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
5494: ** <li> An alternative page cache implementation is specified using
5495: ** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
5496: ** <li> The page cache allocates from its own memory pool supplied
5497: ** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
5498: ** from the heap.
5499: ** </ul>)^
5500: **
5501: ** Beginning with SQLite version 3.7.3, the soft heap limit is enforced
5502: ** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT]
5503: ** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT],
5504: ** the soft heap limit is enforced on every memory allocation. Without
5505: ** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced
5506: ** when memory is allocated by the page cache. Testing suggests that because
5507: ** the page cache is the predominate memory user in SQLite, most
5508: ** applications will achieve adequate soft heap limit enforcement without
5509: ** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT].
5510: **
5511: ** The circumstances under which SQLite will enforce the soft heap limit may
5512: ** changes in future releases of SQLite.
5513: */
5514: SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);
5515:
5516: /*
5517: ** CAPI3REF: Deprecated Soft Heap Limit Interface
5518: ** DEPRECATED
5519: **
5520: ** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
5521: ** interface. This routine is provided for historical compatibility
5522: ** only. All new applications should use the
5523: ** [sqlite3_soft_heap_limit64()] interface rather than this one.
5524: */
5525: SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N);
5526:
5527:
5528: /*
5529: ** CAPI3REF: Extract Metadata About A Column Of A Table
5530: ** METHOD: sqlite3
5531: **
5532: ** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns
5533: ** information about column C of table T in database D
5534: ** on [database connection] X.)^ ^The sqlite3_table_column_metadata()
5535: ** interface returns SQLITE_OK and fills in the non-NULL pointers in
5536: ** the final five arguments with appropriate values if the specified
5537: ** column exists. ^The sqlite3_table_column_metadata() interface returns
5538: ** SQLITE_ERROR and if the specified column does not exist.
5539: ** ^If the column-name parameter to sqlite3_table_column_metadata() is a
5540: ** NULL pointer, then this routine simply checks for the existence of the
5541: ** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it
5542: ** does not.
5543: **
5544: ** ^The column is identified by the second, third and fourth parameters to
5545: ** this function. ^(The second parameter is either the name of the database
5546: ** (i.e. "main", "temp", or an attached database) containing the specified
5547: ** table or NULL.)^ ^If it is NULL, then all attached databases are searched
5548: ** for the table using the same algorithm used by the database engine to
5549: ** resolve unqualified table references.
5550: **
5551: ** ^The third and fourth parameters to this function are the table and column
5552: ** name of the desired column, respectively.
5553: **
5554: ** ^Metadata is returned by writing to the memory locations passed as the 5th
5555: ** and subsequent parameters to this function. ^Any of these arguments may be
5556: ** NULL, in which case the corresponding element of metadata is omitted.
5557: **
5558: ** ^(<blockquote>
5559: ** <table border="1">
5560: ** <tr><th> Parameter <th> Output<br>Type <th> Description
5561: **
5562: ** <tr><td> 5th <td> const char* <td> Data type
5563: ** <tr><td> 6th <td> const char* <td> Name of default collation sequence
5564: ** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint
5565: ** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY
5566: ** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT]
5567: ** </table>
5568: ** </blockquote>)^
5569: **
5570: ** ^The memory pointed to by the character pointers returned for the
5571: ** declaration type and collation sequence is valid until the next
5572: ** call to any SQLite API function.
5573: **
5574: ** ^If the specified table is actually a view, an [error code] is returned.
5575: **
5576: ** ^If the specified column is "rowid", "oid" or "_rowid_" and the table
5577: ** is not a [WITHOUT ROWID] table and an
5578: ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
5579: ** parameters are set for the explicitly declared column. ^(If there is no
5580: ** [INTEGER PRIMARY KEY] column, then the outputs
5581: ** for the [rowid] are set as follows:
5582: **
5583: ** <pre>
5584: ** data type: "INTEGER"
5585: ** collation sequence: "BINARY"
5586: ** not null: 0
5587: ** primary key: 1
5588: ** auto increment: 0
5589: ** </pre>)^
5590: **
5591: ** ^This function causes all database schemas to be read from disk and
5592: ** parsed, if that has not already been done, and returns an error if
5593: ** any errors are encountered while loading the schema.
5594: */
5595: SQLITE_API int sqlite3_table_column_metadata(
5596: sqlite3 *db, /* Connection handle */
5597: const char *zDbName, /* Database name or NULL */
5598: const char *zTableName, /* Table name */
5599: const char *zColumnName, /* Column name */
5600: char const **pzDataType, /* OUTPUT: Declared data type */
5601: char const **pzCollSeq, /* OUTPUT: Collation sequence name */
5602: int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */
5603: int *pPrimaryKey, /* OUTPUT: True if column part of PK */
5604: int *pAutoinc /* OUTPUT: True if column is auto-increment */
5605: );
5606:
5607: /*
5608: ** CAPI3REF: Load An Extension
5609: ** METHOD: sqlite3
5610: **
5611: ** ^This interface loads an SQLite extension library from the named file.
5612: **
5613: ** ^The sqlite3_load_extension() interface attempts to load an
5614: ** [SQLite extension] library contained in the file zFile. If
5615: ** the file cannot be loaded directly, attempts are made to load
5616: ** with various operating-system specific extensions added.
5617: ** So for example, if "samplelib" cannot be loaded, then names like
5618: ** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might
5619: ** be tried also.
5620: **
5621: ** ^The entry point is zProc.
5622: ** ^(zProc may be 0, in which case SQLite will try to come up with an
5623: ** entry point name on its own. It first tries "sqlite3_extension_init".
5624: ** If that does not work, it constructs a name "sqlite3_X_init" where the
5625: ** X is consists of the lower-case equivalent of all ASCII alphabetic
5626: ** characters in the filename from the last "/" to the first following
5627: ** "." and omitting any initial "lib".)^
5628: ** ^The sqlite3_load_extension() interface returns
5629: ** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
5630: ** ^If an error occurs and pzErrMsg is not 0, then the
5631: ** [sqlite3_load_extension()] interface shall attempt to
5632: ** fill *pzErrMsg with error message text stored in memory
5633: ** obtained from [sqlite3_malloc()]. The calling function
5634: ** should free this memory by calling [sqlite3_free()].
5635: **
5636: ** ^Extension loading must be enabled using
5637: ** [sqlite3_enable_load_extension()] or
5638: ** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL)
5639: ** prior to calling this API,
5640: ** otherwise an error will be returned.
5641: **
5642: ** <b>Security warning:</b> It is recommended that the
5643: ** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this
5644: ** interface. The use of the [sqlite3_enable_load_extension()] interface
5645: ** should be avoided. This will keep the SQL function [load_extension()]
5646: ** disabled and prevent SQL injections from giving attackers
5647: ** access to extension loading capabilities.
5648: **
5649: ** See also the [load_extension() SQL function].
5650: */
5651: SQLITE_API int sqlite3_load_extension(
5652: sqlite3 *db, /* Load the extension into this database connection */
5653: const char *zFile, /* Name of the shared library containing extension */
5654: const char *zProc, /* Entry point. Derived from zFile if 0 */
5655: char **pzErrMsg /* Put error message here if not 0 */
5656: );
5657:
5658: /*
5659: ** CAPI3REF: Enable Or Disable Extension Loading
5660: ** METHOD: sqlite3
5661: **
5662: ** ^So as not to open security holes in older applications that are
5663: ** unprepared to deal with [extension loading], and as a means of disabling
5664: ** [extension loading] while evaluating user-entered SQL, the following API
5665: ** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
5666: **
5667: ** ^Extension loading is off by default.
5668: ** ^Call the sqlite3_enable_load_extension() routine with onoff==1
5669: ** to turn extension loading on and call it with onoff==0 to turn
5670: ** it back off again.
5671: **
5672: ** ^This interface enables or disables both the C-API
5673: ** [sqlite3_load_extension()] and the SQL function [load_extension()].
5674: ** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..)
5675: ** to enable or disable only the C-API.)^
5676: **
5677: ** <b>Security warning:</b> It is recommended that extension loading
5678: ** be disabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method
5679: ** rather than this interface, so the [load_extension()] SQL function
5680: ** remains disabled. This will prevent SQL injections from giving attackers
5681: ** access to extension loading capabilities.
5682: */
5683: SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
5684:
5685: /*
5686: ** CAPI3REF: Automatically Load Statically Linked Extensions
5687: **
5688: ** ^This interface causes the xEntryPoint() function to be invoked for
5689: ** each new [database connection] that is created. The idea here is that
5690: ** xEntryPoint() is the entry point for a statically linked [SQLite extension]
5691: ** that is to be automatically loaded into all new database connections.
5692: **
5693: ** ^(Even though the function prototype shows that xEntryPoint() takes
5694: ** no arguments and returns void, SQLite invokes xEntryPoint() with three
5695: ** arguments and expects an integer result as if the signature of the
5696: ** entry point where as follows:
5697: **
5698: ** <blockquote><pre>
5699: ** int xEntryPoint(
5700: ** sqlite3 *db,
5701: ** const char **pzErrMsg,
5702: ** const struct sqlite3_api_routines *pThunk
5703: ** );
5704: ** </pre></blockquote>)^
5705: **
5706: ** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
5707: ** point to an appropriate error message (obtained from [sqlite3_mprintf()])
5708: ** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg
5709: ** is NULL before calling the xEntryPoint(). ^SQLite will invoke
5710: ** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any
5711: ** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
5712: ** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
5713: **
5714: ** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
5715: ** on the list of automatic extensions is a harmless no-op. ^No entry point
5716: ** will be called more than once for each database connection that is opened.
5717: **
5718: ** See also: [sqlite3_reset_auto_extension()]
5719: ** and [sqlite3_cancel_auto_extension()]
5720: */
5721: SQLITE_API int sqlite3_auto_extension(void(*xEntryPoint)(void));
5722:
5723: /*
5724: ** CAPI3REF: Cancel Automatic Extension Loading
5725: **
5726: ** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the
5727: ** initialization routine X that was registered using a prior call to
5728: ** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)]
5729: ** routine returns 1 if initialization routine X was successfully
5730: ** unregistered and it returns 0 if X was not on the list of initialization
5731: ** routines.
5732: */
5733: SQLITE_API int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void));
5734:
5735: /*
5736: ** CAPI3REF: Reset Automatic Extension Loading
5737: **
5738: ** ^This interface disables all automatic extensions previously
5739: ** registered using [sqlite3_auto_extension()].
5740: */
5741: SQLITE_API void sqlite3_reset_auto_extension(void);
5742:
5743: /*
5744: ** The interface to the virtual-table mechanism is currently considered
5745: ** to be experimental. The interface might change in incompatible ways.
5746: ** If this is a problem for you, do not use the interface at this time.
5747: **
5748: ** When the virtual-table mechanism stabilizes, we will declare the
5749: ** interface fixed, support it indefinitely, and remove this comment.
5750: */
5751:
5752: /*
5753: ** Structures used by the virtual table interface
5754: */
5755: typedef struct sqlite3_vtab sqlite3_vtab;
5756: typedef struct sqlite3_index_info sqlite3_index_info;
5757: typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
5758: typedef struct sqlite3_module sqlite3_module;
5759:
5760: /*
5761: ** CAPI3REF: Virtual Table Object
5762: ** KEYWORDS: sqlite3_module {virtual table module}
5763: **
5764: ** This structure, sometimes called a "virtual table module",
5765: ** defines the implementation of a [virtual tables].
5766: ** This structure consists mostly of methods for the module.
5767: **
5768: ** ^A virtual table module is created by filling in a persistent
5769: ** instance of this structure and passing a pointer to that instance
5770: ** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
5771: ** ^The registration remains valid until it is replaced by a different
5772: ** module or until the [database connection] closes. The content
5773: ** of this structure must not change while it is registered with
5774: ** any database connection.
5775: */
5776: struct sqlite3_module {
5777: int iVersion;
5778: int (*xCreate)(sqlite3*, void *pAux,
5779: int argc, const char *const*argv,
5780: sqlite3_vtab **ppVTab, char**);
5781: int (*xConnect)(sqlite3*, void *pAux,
5782: int argc, const char *const*argv,
5783: sqlite3_vtab **ppVTab, char**);
5784: int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
5785: int (*xDisconnect)(sqlite3_vtab *pVTab);
5786: int (*xDestroy)(sqlite3_vtab *pVTab);
5787: int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
5788: int (*xClose)(sqlite3_vtab_cursor*);
5789: int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
5790: int argc, sqlite3_value **argv);
5791: int (*xNext)(sqlite3_vtab_cursor*);
5792: int (*xEof)(sqlite3_vtab_cursor*);
5793: int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
5794: int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
5795: int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
5796: int (*xBegin)(sqlite3_vtab *pVTab);
5797: int (*xSync)(sqlite3_vtab *pVTab);
5798: int (*xCommit)(sqlite3_vtab *pVTab);
5799: int (*xRollback)(sqlite3_vtab *pVTab);
5800: int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
5801: void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
5802: void **ppArg);
5803: int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
5804: /* The methods above are in version 1 of the sqlite_module object. Those
5805: ** below are for version 2 and greater. */
5806: int (*xSavepoint)(sqlite3_vtab *pVTab, int);
5807: int (*xRelease)(sqlite3_vtab *pVTab, int);
5808: int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
5809: };
5810:
5811: /*
5812: ** CAPI3REF: Virtual Table Indexing Information
5813: ** KEYWORDS: sqlite3_index_info
5814: **
5815: ** The sqlite3_index_info structure and its substructures is used as part
5816: ** of the [virtual table] interface to
5817: ** pass information into and receive the reply from the [xBestIndex]
5818: ** method of a [virtual table module]. The fields under **Inputs** are the
5819: ** inputs to xBestIndex and are read-only. xBestIndex inserts its
5820: ** results into the **Outputs** fields.
5821: **
5822: ** ^(The aConstraint[] array records WHERE clause constraints of the form:
5823: **
5824: ** <blockquote>column OP expr</blockquote>
5825: **
5826: ** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is
5827: ** stored in aConstraint[].op using one of the
5828: ** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
5829: ** ^(The index of the column is stored in
5830: ** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the
5831: ** expr on the right-hand side can be evaluated (and thus the constraint
5832: ** is usable) and false if it cannot.)^
5833: **
5834: ** ^The optimizer automatically inverts terms of the form "expr OP column"
5835: ** and makes other simplifications to the WHERE clause in an attempt to
5836: ** get as many WHERE clause terms into the form shown above as possible.
5837: ** ^The aConstraint[] array only reports WHERE clause terms that are
5838: ** relevant to the particular virtual table being queried.
5839: **
5840: ** ^Information about the ORDER BY clause is stored in aOrderBy[].
5841: ** ^Each term of aOrderBy records a column of the ORDER BY clause.
5842: **
5843: ** The colUsed field indicates which columns of the virtual table may be
5844: ** required by the current scan. Virtual table columns are numbered from
5845: ** zero in the order in which they appear within the CREATE TABLE statement
5846: ** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62),
5847: ** the corresponding bit is set within the colUsed mask if the column may be
5848: ** required by SQLite. If the table has at least 64 columns and any column
5849: ** to the right of the first 63 is required, then bit 63 of colUsed is also
5850: ** set. In other words, column iCol may be required if the expression
5851: ** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to
5852: ** non-zero.
5853: **
5854: ** The [xBestIndex] method must fill aConstraintUsage[] with information
5855: ** about what parameters to pass to xFilter. ^If argvIndex>0 then
5856: ** the right-hand side of the corresponding aConstraint[] is evaluated
5857: ** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit
5858: ** is true, then the constraint is assumed to be fully handled by the
5859: ** virtual table and is not checked again by SQLite.)^
5860: **
5861: ** ^The idxNum and idxPtr values are recorded and passed into the
5862: ** [xFilter] method.
5863: ** ^[sqlite3_free()] is used to free idxPtr if and only if
5864: ** needToFreeIdxPtr is true.
5865: **
5866: ** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
5867: ** the correct order to satisfy the ORDER BY clause so that no separate
5868: ** sorting step is required.
5869: **
5870: ** ^The estimatedCost value is an estimate of the cost of a particular
5871: ** strategy. A cost of N indicates that the cost of the strategy is similar
5872: ** to a linear scan of an SQLite table with N rows. A cost of log(N)
5873: ** indicates that the expense of the operation is similar to that of a
5874: ** binary search on a unique indexed field of an SQLite table with N rows.
5875: **
5876: ** ^The estimatedRows value is an estimate of the number of rows that
5877: ** will be returned by the strategy.
5878: **
5879: ** The xBestIndex method may optionally populate the idxFlags field with a
5880: ** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag -
5881: ** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite
5882: ** assumes that the strategy may visit at most one row.
5883: **
5884: ** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then
5885: ** SQLite also assumes that if a call to the xUpdate() method is made as
5886: ** part of the same statement to delete or update a virtual table row and the
5887: ** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback
5888: ** any database changes. In other words, if the xUpdate() returns
5889: ** SQLITE_CONSTRAINT, the database contents must be exactly as they were
5890: ** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not
5891: ** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by
5892: ** the xUpdate method are automatically rolled back by SQLite.
5893: **
5894: ** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info
5895: ** structure for SQLite version 3.8.2. If a virtual table extension is
5896: ** used with an SQLite version earlier than 3.8.2, the results of attempting
5897: ** to read or write the estimatedRows field are undefined (but are likely
5898: ** to included crashing the application). The estimatedRows field should
5899: ** therefore only be used if [sqlite3_libversion_number()] returns a
5900: ** value greater than or equal to 3008002. Similarly, the idxFlags field
5901: ** was added for version 3.9.0. It may therefore only be used if
5902: ** sqlite3_libversion_number() returns a value greater than or equal to
5903: ** 3009000.
5904: */
5905: struct sqlite3_index_info {
5906: /* Inputs */
5907: int nConstraint; /* Number of entries in aConstraint */
5908: struct sqlite3_index_constraint {
5909: int iColumn; /* Column constrained. -1 for ROWID */
5910: unsigned char op; /* Constraint operator */
5911: unsigned char usable; /* True if this constraint is usable */
5912: int iTermOffset; /* Used internally - xBestIndex should ignore */
5913: } *aConstraint; /* Table of WHERE clause constraints */
5914: int nOrderBy; /* Number of terms in the ORDER BY clause */
5915: struct sqlite3_index_orderby {
5916: int iColumn; /* Column number */
5917: unsigned char desc; /* True for DESC. False for ASC. */
5918: } *aOrderBy; /* The ORDER BY clause */
5919: /* Outputs */
5920: struct sqlite3_index_constraint_usage {
5921: int argvIndex; /* if >0, constraint is part of argv to xFilter */
5922: unsigned char omit; /* Do not code a test for this constraint */
5923: } *aConstraintUsage;
5924: int idxNum; /* Number used to identify the index */
5925: char *idxStr; /* String, possibly obtained from sqlite3_malloc */
5926: int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */
5927: int orderByConsumed; /* True if output is already ordered */
5928: double estimatedCost; /* Estimated cost of using this index */
5929: /* Fields below are only available in SQLite 3.8.2 and later */
5930: sqlite3_int64 estimatedRows; /* Estimated number of rows returned */
5931: /* Fields below are only available in SQLite 3.9.0 and later */
5932: int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */
5933: /* Fields below are only available in SQLite 3.10.0 and later */
5934: sqlite3_uint64 colUsed; /* Input: Mask of columns used by statement */
5935: };
5936:
5937: /*
5938: ** CAPI3REF: Virtual Table Scan Flags
5939: */
5940: #define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */
5941:
5942: /*
5943: ** CAPI3REF: Virtual Table Constraint Operator Codes
5944: **
5945: ** These macros defined the allowed values for the
5946: ** [sqlite3_index_info].aConstraint[].op field. Each value represents
5947: ** an operator that is part of a constraint term in the wHERE clause of
5948: ** a query that uses a [virtual table].
5949: */
5950: #define SQLITE_INDEX_CONSTRAINT_EQ 2
5951: #define SQLITE_INDEX_CONSTRAINT_GT 4
5952: #define SQLITE_INDEX_CONSTRAINT_LE 8
5953: #define SQLITE_INDEX_CONSTRAINT_LT 16
5954: #define SQLITE_INDEX_CONSTRAINT_GE 32
5955: #define SQLITE_INDEX_CONSTRAINT_MATCH 64
5956: #define SQLITE_INDEX_CONSTRAINT_LIKE 65
5957: #define SQLITE_INDEX_CONSTRAINT_GLOB 66
5958: #define SQLITE_INDEX_CONSTRAINT_REGEXP 67
5959:
5960: /*
5961: ** CAPI3REF: Register A Virtual Table Implementation
5962: ** METHOD: sqlite3
5963: **
5964: ** ^These routines are used to register a new [virtual table module] name.
5965: ** ^Module names must be registered before
5966: ** creating a new [virtual table] using the module and before using a
5967: ** preexisting [virtual table] for the module.
5968: **
5969: ** ^The module name is registered on the [database connection] specified
5970: ** by the first parameter. ^The name of the module is given by the
5971: ** second parameter. ^The third parameter is a pointer to
5972: ** the implementation of the [virtual table module]. ^The fourth
5973: ** parameter is an arbitrary client data pointer that is passed through
5974: ** into the [xCreate] and [xConnect] methods of the virtual table module
5975: ** when a new virtual table is be being created or reinitialized.
5976: **
5977: ** ^The sqlite3_create_module_v2() interface has a fifth parameter which
5978: ** is a pointer to a destructor for the pClientData. ^SQLite will
5979: ** invoke the destructor function (if it is not NULL) when SQLite
5980: ** no longer needs the pClientData pointer. ^The destructor will also
5981: ** be invoked if the call to sqlite3_create_module_v2() fails.
5982: ** ^The sqlite3_create_module()
5983: ** interface is equivalent to sqlite3_create_module_v2() with a NULL
5984: ** destructor.
5985: */
5986: SQLITE_API int sqlite3_create_module(
5987: sqlite3 *db, /* SQLite connection to register module with */
5988: const char *zName, /* Name of the module */
5989: const sqlite3_module *p, /* Methods for the module */
5990: void *pClientData /* Client data for xCreate/xConnect */
5991: );
5992: SQLITE_API int sqlite3_create_module_v2(
5993: sqlite3 *db, /* SQLite connection to register module with */
5994: const char *zName, /* Name of the module */
5995: const sqlite3_module *p, /* Methods for the module */
5996: void *pClientData, /* Client data for xCreate/xConnect */
5997: void(*xDestroy)(void*) /* Module destructor function */
5998: );
5999:
6000: /*
6001: ** CAPI3REF: Virtual Table Instance Object
6002: ** KEYWORDS: sqlite3_vtab
6003: **
6004: ** Every [virtual table module] implementation uses a subclass
6005: ** of this object to describe a particular instance
6006: ** of the [virtual table]. Each subclass will
6007: ** be tailored to the specific needs of the module implementation.
6008: ** The purpose of this superclass is to define certain fields that are
6009: ** common to all module implementations.
6010: **
6011: ** ^Virtual tables methods can set an error message by assigning a
6012: ** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should
6013: ** take care that any prior string is freed by a call to [sqlite3_free()]
6014: ** prior to assigning a new string to zErrMsg. ^After the error message
6015: ** is delivered up to the client application, the string will be automatically
6016: ** freed by sqlite3_free() and the zErrMsg field will be zeroed.
6017: */
6018: struct sqlite3_vtab {
6019: const sqlite3_module *pModule; /* The module for this virtual table */
6020: int nRef; /* Number of open cursors */
6021: char *zErrMsg; /* Error message from sqlite3_mprintf() */
6022: /* Virtual table implementations will typically add additional fields */
6023: };
6024:
6025: /*
6026: ** CAPI3REF: Virtual Table Cursor Object
6027: ** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
6028: **
6029: ** Every [virtual table module] implementation uses a subclass of the
6030: ** following structure to describe cursors that point into the
6031: ** [virtual table] and are used
6032: ** to loop through the virtual table. Cursors are created using the
6033: ** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
6034: ** by the [sqlite3_module.xClose | xClose] method. Cursors are used
6035: ** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
6036: ** of the module. Each module implementation will define
6037: ** the content of a cursor structure to suit its own needs.
6038: **
6039: ** This superclass exists in order to define fields of the cursor that
6040: ** are common to all implementations.
6041: */
6042: struct sqlite3_vtab_cursor {
6043: sqlite3_vtab *pVtab; /* Virtual table of this cursor */
6044: /* Virtual table implementations will typically add additional fields */
6045: };
6046:
6047: /*
6048: ** CAPI3REF: Declare The Schema Of A Virtual Table
6049: **
6050: ** ^The [xCreate] and [xConnect] methods of a
6051: ** [virtual table module] call this interface
6052: ** to declare the format (the names and datatypes of the columns) of
6053: ** the virtual tables they implement.
6054: */
6055: SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
6056:
6057: /*
6058: ** CAPI3REF: Overload A Function For A Virtual Table
6059: ** METHOD: sqlite3
6060: **
6061: ** ^(Virtual tables can provide alternative implementations of functions
6062: ** using the [xFindFunction] method of the [virtual table module].
6063: ** But global versions of those functions
6064: ** must exist in order to be overloaded.)^
6065: **
6066: ** ^(This API makes sure a global version of a function with a particular
6067: ** name and number of parameters exists. If no such function exists
6068: ** before this API is called, a new function is created.)^ ^The implementation
6069: ** of the new function always causes an exception to be thrown. So
6070: ** the new function is not good for anything by itself. Its only
6071: ** purpose is to be a placeholder function that can be overloaded
6072: ** by a [virtual table].
6073: */
6074: SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
6075:
6076: /*
6077: ** The interface to the virtual-table mechanism defined above (back up
6078: ** to a comment remarkably similar to this one) is currently considered
6079: ** to be experimental. The interface might change in incompatible ways.
6080: ** If this is a problem for you, do not use the interface at this time.
6081: **
6082: ** When the virtual-table mechanism stabilizes, we will declare the
6083: ** interface fixed, support it indefinitely, and remove this comment.
6084: */
6085:
6086: /*
6087: ** CAPI3REF: A Handle To An Open BLOB
6088: ** KEYWORDS: {BLOB handle} {BLOB handles}
6089: **
6090: ** An instance of this object represents an open BLOB on which
6091: ** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
6092: ** ^Objects of this type are created by [sqlite3_blob_open()]
6093: ** and destroyed by [sqlite3_blob_close()].
6094: ** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
6095: ** can be used to read or write small subsections of the BLOB.
6096: ** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
6097: */
6098: typedef struct sqlite3_blob sqlite3_blob;
6099:
6100: /*
6101: ** CAPI3REF: Open A BLOB For Incremental I/O
6102: ** METHOD: sqlite3
6103: ** CONSTRUCTOR: sqlite3_blob
6104: **
6105: ** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
6106: ** in row iRow, column zColumn, table zTable in database zDb;
6107: ** in other words, the same BLOB that would be selected by:
6108: **
6109: ** <pre>
6110: ** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
6111: ** </pre>)^
6112: **
6113: ** ^(Parameter zDb is not the filename that contains the database, but
6114: ** rather the symbolic name of the database. For attached databases, this is
6115: ** the name that appears after the AS keyword in the [ATTACH] statement.
6116: ** For the main database file, the database name is "main". For TEMP
6117: ** tables, the database name is "temp".)^
6118: **
6119: ** ^If the flags parameter is non-zero, then the BLOB is opened for read
6120: ** and write access. ^If the flags parameter is zero, the BLOB is opened for
6121: ** read-only access.
6122: **
6123: ** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored
6124: ** in *ppBlob. Otherwise an [error code] is returned and, unless the error
6125: ** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided
6126: ** the API is not misused, it is always safe to call [sqlite3_blob_close()]
6127: ** on *ppBlob after this function it returns.
6128: **
6129: ** This function fails with SQLITE_ERROR if any of the following are true:
6130: ** <ul>
6131: ** <li> ^(Database zDb does not exist)^,
6132: ** <li> ^(Table zTable does not exist within database zDb)^,
6133: ** <li> ^(Table zTable is a WITHOUT ROWID table)^,
6134: ** <li> ^(Column zColumn does not exist)^,
6135: ** <li> ^(Row iRow is not present in the table)^,
6136: ** <li> ^(The specified column of row iRow contains a value that is not
6137: ** a TEXT or BLOB value)^,
6138: ** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE
6139: ** constraint and the blob is being opened for read/write access)^,
6140: ** <li> ^([foreign key constraints | Foreign key constraints] are enabled,
6141: ** column zColumn is part of a [child key] definition and the blob is
6142: ** being opened for read/write access)^.
6143: ** </ul>
6144: **
6145: ** ^Unless it returns SQLITE_MISUSE, this function sets the
6146: ** [database connection] error code and message accessible via
6147: ** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
6148: **
6149: **
6150: ** ^(If the row that a BLOB handle points to is modified by an
6151: ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
6152: ** then the BLOB handle is marked as "expired".
6153: ** This is true if any column of the row is changed, even a column
6154: ** other than the one the BLOB handle is open on.)^
6155: ** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
6156: ** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
6157: ** ^(Changes written into a BLOB prior to the BLOB expiring are not
6158: ** rolled back by the expiration of the BLOB. Such changes will eventually
6159: ** commit if the transaction continues to completion.)^
6160: **
6161: ** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
6162: ** the opened blob. ^The size of a blob may not be changed by this
6163: ** interface. Use the [UPDATE] SQL command to change the size of a
6164: ** blob.
6165: **
6166: ** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
6167: ** and the built-in [zeroblob] SQL function may be used to create a
6168: ** zero-filled blob to read or write using the incremental-blob interface.
6169: **
6170: ** To avoid a resource leak, every open [BLOB handle] should eventually
6171: ** be released by a call to [sqlite3_blob_close()].
6172: */
6173: SQLITE_API int sqlite3_blob_open(
6174: sqlite3*,
6175: const char *zDb,
6176: const char *zTable,
6177: const char *zColumn,
6178: sqlite3_int64 iRow,
6179: int flags,
6180: sqlite3_blob **ppBlob
6181: );
6182:
6183: /*
6184: ** CAPI3REF: Move a BLOB Handle to a New Row
6185: ** METHOD: sqlite3_blob
6186: **
6187: ** ^This function is used to move an existing blob handle so that it points
6188: ** to a different row of the same database table. ^The new row is identified
6189: ** by the rowid value passed as the second argument. Only the row can be
6190: ** changed. ^The database, table and column on which the blob handle is open
6191: ** remain the same. Moving an existing blob handle to a new row can be
6192: ** faster than closing the existing handle and opening a new one.
6193: **
6194: ** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
6195: ** it must exist and there must be either a blob or text value stored in
6196: ** the nominated column.)^ ^If the new row is not present in the table, or if
6197: ** it does not contain a blob or text value, or if another error occurs, an
6198: ** SQLite error code is returned and the blob handle is considered aborted.
6199: ** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
6200: ** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
6201: ** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
6202: ** always returns zero.
6203: **
6204: ** ^This function sets the database handle error code and message.
6205: */
6206: SQLITE_API int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
6207:
6208: /*
6209: ** CAPI3REF: Close A BLOB Handle
6210: ** DESTRUCTOR: sqlite3_blob
6211: **
6212: ** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed
6213: ** unconditionally. Even if this routine returns an error code, the
6214: ** handle is still closed.)^
6215: **
6216: ** ^If the blob handle being closed was opened for read-write access, and if
6217: ** the database is in auto-commit mode and there are no other open read-write
6218: ** blob handles or active write statements, the current transaction is
6219: ** committed. ^If an error occurs while committing the transaction, an error
6220: ** code is returned and the transaction rolled back.
6221: **
6222: ** Calling this function with an argument that is not a NULL pointer or an
6223: ** open blob handle results in undefined behaviour. ^Calling this routine
6224: ** with a null pointer (such as would be returned by a failed call to
6225: ** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function
6226: ** is passed a valid open blob handle, the values returned by the
6227: ** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning.
6228: */
6229: SQLITE_API int sqlite3_blob_close(sqlite3_blob *);
6230:
6231: /*
6232: ** CAPI3REF: Return The Size Of An Open BLOB
6233: ** METHOD: sqlite3_blob
6234: **
6235: ** ^Returns the size in bytes of the BLOB accessible via the
6236: ** successfully opened [BLOB handle] in its only argument. ^The
6237: ** incremental blob I/O routines can only read or overwriting existing
6238: ** blob content; they cannot change the size of a blob.
6239: **
6240: ** This routine only works on a [BLOB handle] which has been created
6241: ** by a prior successful call to [sqlite3_blob_open()] and which has not
6242: ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
6243: ** to this routine results in undefined and probably undesirable behavior.
6244: */
6245: SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *);
6246:
6247: /*
6248: ** CAPI3REF: Read Data From A BLOB Incrementally
6249: ** METHOD: sqlite3_blob
6250: **
6251: ** ^(This function is used to read data from an open [BLOB handle] into a
6252: ** caller-supplied buffer. N bytes of data are copied into buffer Z
6253: ** from the open BLOB, starting at offset iOffset.)^
6254: **
6255: ** ^If offset iOffset is less than N bytes from the end of the BLOB,
6256: ** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is
6257: ** less than zero, [SQLITE_ERROR] is returned and no data is read.
6258: ** ^The size of the blob (and hence the maximum value of N+iOffset)
6259: ** can be determined using the [sqlite3_blob_bytes()] interface.
6260: **
6261: ** ^An attempt to read from an expired [BLOB handle] fails with an
6262: ** error code of [SQLITE_ABORT].
6263: **
6264: ** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
6265: ** Otherwise, an [error code] or an [extended error code] is returned.)^
6266: **
6267: ** This routine only works on a [BLOB handle] which has been created
6268: ** by a prior successful call to [sqlite3_blob_open()] and which has not
6269: ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
6270: ** to this routine results in undefined and probably undesirable behavior.
6271: **
6272: ** See also: [sqlite3_blob_write()].
6273: */
6274: SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
6275:
6276: /*
6277: ** CAPI3REF: Write Data Into A BLOB Incrementally
6278: ** METHOD: sqlite3_blob
6279: **
6280: ** ^(This function is used to write data into an open [BLOB handle] from a
6281: ** caller-supplied buffer. N bytes of data are copied from the buffer Z
6282: ** into the open BLOB, starting at offset iOffset.)^
6283: **
6284: ** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
6285: ** Otherwise, an [error code] or an [extended error code] is returned.)^
6286: ** ^Unless SQLITE_MISUSE is returned, this function sets the
6287: ** [database connection] error code and message accessible via
6288: ** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
6289: **
6290: ** ^If the [BLOB handle] passed as the first argument was not opened for
6291: ** writing (the flags parameter to [sqlite3_blob_open()] was zero),
6292: ** this function returns [SQLITE_READONLY].
6293: **
6294: ** This function may only modify the contents of the BLOB; it is
6295: ** not possible to increase the size of a BLOB using this API.
6296: ** ^If offset iOffset is less than N bytes from the end of the BLOB,
6297: ** [SQLITE_ERROR] is returned and no data is written. The size of the
6298: ** BLOB (and hence the maximum value of N+iOffset) can be determined
6299: ** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less
6300: ** than zero [SQLITE_ERROR] is returned and no data is written.
6301: **
6302: ** ^An attempt to write to an expired [BLOB handle] fails with an
6303: ** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred
6304: ** before the [BLOB handle] expired are not rolled back by the
6305: ** expiration of the handle, though of course those changes might
6306: ** have been overwritten by the statement that expired the BLOB handle
6307: ** or by other independent statements.
6308: **
6309: ** This routine only works on a [BLOB handle] which has been created
6310: ** by a prior successful call to [sqlite3_blob_open()] and which has not
6311: ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
6312: ** to this routine results in undefined and probably undesirable behavior.
6313: **
6314: ** See also: [sqlite3_blob_read()].
6315: */
6316: SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
6317:
6318: /*
6319: ** CAPI3REF: Virtual File System Objects
6320: **
6321: ** A virtual filesystem (VFS) is an [sqlite3_vfs] object
6322: ** that SQLite uses to interact
6323: ** with the underlying operating system. Most SQLite builds come with a
6324: ** single default VFS that is appropriate for the host computer.
6325: ** New VFSes can be registered and existing VFSes can be unregistered.
6326: ** The following interfaces are provided.
6327: **
6328: ** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
6329: ** ^Names are case sensitive.
6330: ** ^Names are zero-terminated UTF-8 strings.
6331: ** ^If there is no match, a NULL pointer is returned.
6332: ** ^If zVfsName is NULL then the default VFS is returned.
6333: **
6334: ** ^New VFSes are registered with sqlite3_vfs_register().
6335: ** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
6336: ** ^The same VFS can be registered multiple times without injury.
6337: ** ^To make an existing VFS into the default VFS, register it again
6338: ** with the makeDflt flag set. If two different VFSes with the
6339: ** same name are registered, the behavior is undefined. If a
6340: ** VFS is registered with a name that is NULL or an empty string,
6341: ** then the behavior is undefined.
6342: **
6343: ** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
6344: ** ^(If the default VFS is unregistered, another VFS is chosen as
6345: ** the default. The choice for the new VFS is arbitrary.)^
6346: */
6347: SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
6348: SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
6349: SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*);
6350:
6351: /*
6352: ** CAPI3REF: Mutexes
6353: **
6354: ** The SQLite core uses these routines for thread
6355: ** synchronization. Though they are intended for internal
6356: ** use by SQLite, code that links against SQLite is
6357: ** permitted to use any of these routines.
6358: **
6359: ** The SQLite source code contains multiple implementations
6360: ** of these mutex routines. An appropriate implementation
6361: ** is selected automatically at compile-time. The following
6362: ** implementations are available in the SQLite core:
6363: **
6364: ** <ul>
6365: ** <li> SQLITE_MUTEX_PTHREADS
6366: ** <li> SQLITE_MUTEX_W32
6367: ** <li> SQLITE_MUTEX_NOOP
6368: ** </ul>
6369: **
6370: ** The SQLITE_MUTEX_NOOP implementation is a set of routines
6371: ** that does no real locking and is appropriate for use in
6372: ** a single-threaded application. The SQLITE_MUTEX_PTHREADS and
6373: ** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
6374: ** and Windows.
6375: **
6376: ** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
6377: ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
6378: ** implementation is included with the library. In this case the
6379: ** application must supply a custom mutex implementation using the
6380: ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
6381: ** before calling sqlite3_initialize() or any other public sqlite3_
6382: ** function that calls sqlite3_initialize().
6383: **
6384: ** ^The sqlite3_mutex_alloc() routine allocates a new
6385: ** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc()
6386: ** routine returns NULL if it is unable to allocate the requested
6387: ** mutex. The argument to sqlite3_mutex_alloc() must one of these
6388: ** integer constants:
6389: **
6390: ** <ul>
6391: ** <li> SQLITE_MUTEX_FAST
6392: ** <li> SQLITE_MUTEX_RECURSIVE
6393: ** <li> SQLITE_MUTEX_STATIC_MASTER
6394: ** <li> SQLITE_MUTEX_STATIC_MEM
6395: ** <li> SQLITE_MUTEX_STATIC_OPEN
6396: ** <li> SQLITE_MUTEX_STATIC_PRNG
6397: ** <li> SQLITE_MUTEX_STATIC_LRU
6398: ** <li> SQLITE_MUTEX_STATIC_PMEM
6399: ** <li> SQLITE_MUTEX_STATIC_APP1
6400: ** <li> SQLITE_MUTEX_STATIC_APP2
6401: ** <li> SQLITE_MUTEX_STATIC_APP3
6402: ** <li> SQLITE_MUTEX_STATIC_VFS1
6403: ** <li> SQLITE_MUTEX_STATIC_VFS2
6404: ** <li> SQLITE_MUTEX_STATIC_VFS3
6405: ** </ul>
6406: **
6407: ** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
6408: ** cause sqlite3_mutex_alloc() to create
6409: ** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
6410: ** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
6411: ** The mutex implementation does not need to make a distinction
6412: ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
6413: ** not want to. SQLite will only request a recursive mutex in
6414: ** cases where it really needs one. If a faster non-recursive mutex
6415: ** implementation is available on the host platform, the mutex subsystem
6416: ** might return such a mutex in response to SQLITE_MUTEX_FAST.
6417: **
6418: ** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
6419: ** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
6420: ** a pointer to a static preexisting mutex. ^Nine static mutexes are
6421: ** used by the current version of SQLite. Future versions of SQLite
6422: ** may add additional static mutexes. Static mutexes are for internal
6423: ** use by SQLite only. Applications that use SQLite mutexes should
6424: ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
6425: ** SQLITE_MUTEX_RECURSIVE.
6426: **
6427: ** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
6428: ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
6429: ** returns a different mutex on every call. ^For the static
6430: ** mutex types, the same mutex is returned on every call that has
6431: ** the same type number.
6432: **
6433: ** ^The sqlite3_mutex_free() routine deallocates a previously
6434: ** allocated dynamic mutex. Attempting to deallocate a static
6435: ** mutex results in undefined behavior.
6436: **
6437: ** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
6438: ** to enter a mutex. ^If another thread is already within the mutex,
6439: ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
6440: ** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
6441: ** upon successful entry. ^(Mutexes created using
6442: ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
6443: ** In such cases, the
6444: ** mutex must be exited an equal number of times before another thread
6445: ** can enter.)^ If the same thread tries to enter any mutex other
6446: ** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined.
6447: **
6448: ** ^(Some systems (for example, Windows 95) do not support the operation
6449: ** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try()
6450: ** will always return SQLITE_BUSY. The SQLite core only ever uses
6451: ** sqlite3_mutex_try() as an optimization so this is acceptable
6452: ** behavior.)^
6453: **
6454: ** ^The sqlite3_mutex_leave() routine exits a mutex that was
6455: ** previously entered by the same thread. The behavior
6456: ** is undefined if the mutex is not currently entered by the
6457: ** calling thread or is not currently allocated.
6458: **
6459: ** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
6460: ** sqlite3_mutex_leave() is a NULL pointer, then all three routines
6461: ** behave as no-ops.
6462: **
6463: ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
6464: */
6465: SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int);
6466: SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*);
6467: SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*);
6468: SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*);
6469: SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*);
6470:
6471: /*
6472: ** CAPI3REF: Mutex Methods Object
6473: **
6474: ** An instance of this structure defines the low-level routines
6475: ** used to allocate and use mutexes.
6476: **
6477: ** Usually, the default mutex implementations provided by SQLite are
6478: ** sufficient, however the application has the option of substituting a custom
6479: ** implementation for specialized deployments or systems for which SQLite
6480: ** does not provide a suitable implementation. In this case, the application
6481: ** creates and populates an instance of this structure to pass
6482: ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
6483: ** Additionally, an instance of this structure can be used as an
6484: ** output variable when querying the system for the current mutex
6485: ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
6486: **
6487: ** ^The xMutexInit method defined by this structure is invoked as
6488: ** part of system initialization by the sqlite3_initialize() function.
6489: ** ^The xMutexInit routine is called by SQLite exactly once for each
6490: ** effective call to [sqlite3_initialize()].
6491: **
6492: ** ^The xMutexEnd method defined by this structure is invoked as
6493: ** part of system shutdown by the sqlite3_shutdown() function. The
6494: ** implementation of this method is expected to release all outstanding
6495: ** resources obtained by the mutex methods implementation, especially
6496: ** those obtained by the xMutexInit method. ^The xMutexEnd()
6497: ** interface is invoked exactly once for each call to [sqlite3_shutdown()].
6498: **
6499: ** ^(The remaining seven methods defined by this structure (xMutexAlloc,
6500: ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
6501: ** xMutexNotheld) implement the following interfaces (respectively):
6502: **
6503: ** <ul>
6504: ** <li> [sqlite3_mutex_alloc()] </li>
6505: ** <li> [sqlite3_mutex_free()] </li>
6506: ** <li> [sqlite3_mutex_enter()] </li>
6507: ** <li> [sqlite3_mutex_try()] </li>
6508: ** <li> [sqlite3_mutex_leave()] </li>
6509: ** <li> [sqlite3_mutex_held()] </li>
6510: ** <li> [sqlite3_mutex_notheld()] </li>
6511: ** </ul>)^
6512: **
6513: ** The only difference is that the public sqlite3_XXX functions enumerated
6514: ** above silently ignore any invocations that pass a NULL pointer instead
6515: ** of a valid mutex handle. The implementations of the methods defined
6516: ** by this structure are not required to handle this case, the results
6517: ** of passing a NULL pointer instead of a valid mutex handle are undefined
6518: ** (i.e. it is acceptable to provide an implementation that segfaults if
6519: ** it is passed a NULL pointer).
6520: **
6521: ** The xMutexInit() method must be threadsafe. It must be harmless to
6522: ** invoke xMutexInit() multiple times within the same process and without
6523: ** intervening calls to xMutexEnd(). Second and subsequent calls to
6524: ** xMutexInit() must be no-ops.
6525: **
6526: ** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
6527: ** and its associates). Similarly, xMutexAlloc() must not use SQLite memory
6528: ** allocation for a static mutex. ^However xMutexAlloc() may use SQLite
6529: ** memory allocation for a fast or recursive mutex.
6530: **
6531: ** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
6532: ** called, but only if the prior call to xMutexInit returned SQLITE_OK.
6533: ** If xMutexInit fails in any way, it is expected to clean up after itself
6534: ** prior to returning.
6535: */
6536: typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
6537: struct sqlite3_mutex_methods {
6538: int (*xMutexInit)(void);
6539: int (*xMutexEnd)(void);
6540: sqlite3_mutex *(*xMutexAlloc)(int);
6541: void (*xMutexFree)(sqlite3_mutex *);
6542: void (*xMutexEnter)(sqlite3_mutex *);
6543: int (*xMutexTry)(sqlite3_mutex *);
6544: void (*xMutexLeave)(sqlite3_mutex *);
6545: int (*xMutexHeld)(sqlite3_mutex *);
6546: int (*xMutexNotheld)(sqlite3_mutex *);
6547: };
6548:
6549: /*
6550: ** CAPI3REF: Mutex Verification Routines
6551: **
6552: ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
6553: ** are intended for use inside assert() statements. The SQLite core
6554: ** never uses these routines except inside an assert() and applications
6555: ** are advised to follow the lead of the core. The SQLite core only
6556: ** provides implementations for these routines when it is compiled
6557: ** with the SQLITE_DEBUG flag. External mutex implementations
6558: ** are only required to provide these routines if SQLITE_DEBUG is
6559: ** defined and if NDEBUG is not defined.
6560: **
6561: ** These routines should return true if the mutex in their argument
6562: ** is held or not held, respectively, by the calling thread.
6563: **
6564: ** The implementation is not required to provide versions of these
6565: ** routines that actually work. If the implementation does not provide working
6566: ** versions of these routines, it should at least provide stubs that always
6567: ** return true so that one does not get spurious assertion failures.
6568: **
6569: ** If the argument to sqlite3_mutex_held() is a NULL pointer then
6570: ** the routine should return 1. This seems counter-intuitive since
6571: ** clearly the mutex cannot be held if it does not exist. But
6572: ** the reason the mutex does not exist is because the build is not
6573: ** using mutexes. And we do not want the assert() containing the
6574: ** call to sqlite3_mutex_held() to fail, so a non-zero return is
6575: ** the appropriate thing to do. The sqlite3_mutex_notheld()
6576: ** interface should also return 1 when given a NULL pointer.
6577: */
6578: #ifndef NDEBUG
6579: SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*);
6580: SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*);
6581: #endif
6582:
6583: /*
6584: ** CAPI3REF: Mutex Types
6585: **
6586: ** The [sqlite3_mutex_alloc()] interface takes a single argument
6587: ** which is one of these integer constants.
6588: **
6589: ** The set of static mutexes may change from one SQLite release to the
6590: ** next. Applications that override the built-in mutex logic must be
6591: ** prepared to accommodate additional static mutexes.
6592: */
6593: #define SQLITE_MUTEX_FAST 0
6594: #define SQLITE_MUTEX_RECURSIVE 1
6595: #define SQLITE_MUTEX_STATIC_MASTER 2
6596: #define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */
6597: #define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */
6598: #define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */
6599: #define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */
6600: #define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */
6601: #define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */
6602: #define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */
6603: #define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */
6604: #define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */
6605: #define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */
6606: #define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */
6607: #define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */
6608: #define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */
6609:
6610: /*
6611: ** CAPI3REF: Retrieve the mutex for a database connection
6612: ** METHOD: sqlite3
6613: **
6614: ** ^This interface returns a pointer the [sqlite3_mutex] object that
6615: ** serializes access to the [database connection] given in the argument
6616: ** when the [threading mode] is Serialized.
6617: ** ^If the [threading mode] is Single-thread or Multi-thread then this
6618: ** routine returns a NULL pointer.
6619: */
6620: SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
6621:
6622: /*
6623: ** CAPI3REF: Low-Level Control Of Database Files
6624: ** METHOD: sqlite3
6625: **
6626: ** ^The [sqlite3_file_control()] interface makes a direct call to the
6627: ** xFileControl method for the [sqlite3_io_methods] object associated
6628: ** with a particular database identified by the second argument. ^The
6629: ** name of the database is "main" for the main database or "temp" for the
6630: ** TEMP database, or the name that appears after the AS keyword for
6631: ** databases that are added using the [ATTACH] SQL command.
6632: ** ^A NULL pointer can be used in place of "main" to refer to the
6633: ** main database file.
6634: ** ^The third and fourth parameters to this routine
6635: ** are passed directly through to the second and third parameters of
6636: ** the xFileControl method. ^The return value of the xFileControl
6637: ** method becomes the return value of this routine.
6638: **
6639: ** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes
6640: ** a pointer to the underlying [sqlite3_file] object to be written into
6641: ** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER
6642: ** case is a short-circuit path which does not actually invoke the
6643: ** underlying sqlite3_io_methods.xFileControl method.
6644: **
6645: ** ^If the second parameter (zDbName) does not match the name of any
6646: ** open database file, then SQLITE_ERROR is returned. ^This error
6647: ** code is not remembered and will not be recalled by [sqlite3_errcode()]
6648: ** or [sqlite3_errmsg()]. The underlying xFileControl method might
6649: ** also return SQLITE_ERROR. There is no way to distinguish between
6650: ** an incorrect zDbName and an SQLITE_ERROR return from the underlying
6651: ** xFileControl method.
6652: **
6653: ** See also: [SQLITE_FCNTL_LOCKSTATE]
6654: */
6655: SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
6656:
6657: /*
6658: ** CAPI3REF: Testing Interface
6659: **
6660: ** ^The sqlite3_test_control() interface is used to read out internal
6661: ** state of SQLite and to inject faults into SQLite for testing
6662: ** purposes. ^The first parameter is an operation code that determines
6663: ** the number, meaning, and operation of all subsequent parameters.
6664: **
6665: ** This interface is not for use by applications. It exists solely
6666: ** for verifying the correct operation of the SQLite library. Depending
6667: ** on how the SQLite library is compiled, this interface might not exist.
6668: **
6669: ** The details of the operation codes, their meanings, the parameters
6670: ** they take, and what they do are all subject to change without notice.
6671: ** Unlike most of the SQLite API, this function is not guaranteed to
6672: ** operate consistently from one release to the next.
6673: */
6674: SQLITE_API int sqlite3_test_control(int op, ...);
6675:
6676: /*
6677: ** CAPI3REF: Testing Interface Operation Codes
6678: **
6679: ** These constants are the valid operation code parameters used
6680: ** as the first argument to [sqlite3_test_control()].
6681: **
6682: ** These parameters and their meanings are subject to change
6683: ** without notice. These values are for testing purposes only.
6684: ** Applications should not use any of these parameters or the
6685: ** [sqlite3_test_control()] interface.
6686: */
6687: #define SQLITE_TESTCTRL_FIRST 5
6688: #define SQLITE_TESTCTRL_PRNG_SAVE 5
6689: #define SQLITE_TESTCTRL_PRNG_RESTORE 6
6690: #define SQLITE_TESTCTRL_PRNG_RESET 7
6691: #define SQLITE_TESTCTRL_BITVEC_TEST 8
6692: #define SQLITE_TESTCTRL_FAULT_INSTALL 9
6693: #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10
6694: #define SQLITE_TESTCTRL_PENDING_BYTE 11
6695: #define SQLITE_TESTCTRL_ASSERT 12
6696: #define SQLITE_TESTCTRL_ALWAYS 13
6697: #define SQLITE_TESTCTRL_RESERVE 14
6698: #define SQLITE_TESTCTRL_OPTIMIZATIONS 15
6699: #define SQLITE_TESTCTRL_ISKEYWORD 16
6700: #define SQLITE_TESTCTRL_SCRATCHMALLOC 17
6701: #define SQLITE_TESTCTRL_LOCALTIME_FAULT 18
6702: #define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */
6703: #define SQLITE_TESTCTRL_NEVER_CORRUPT 20
6704: #define SQLITE_TESTCTRL_VDBE_COVERAGE 21
6705: #define SQLITE_TESTCTRL_BYTEORDER 22
6706: #define SQLITE_TESTCTRL_ISINIT 23
6707: #define SQLITE_TESTCTRL_SORTER_MMAP 24
6708: #define SQLITE_TESTCTRL_IMPOSTER 25
6709: #define SQLITE_TESTCTRL_LAST 25
6710:
6711: /*
6712: ** CAPI3REF: SQLite Runtime Status
6713: **
6714: ** ^These interfaces are used to retrieve runtime status information
6715: ** about the performance of SQLite, and optionally to reset various
6716: ** highwater marks. ^The first argument is an integer code for
6717: ** the specific parameter to measure. ^(Recognized integer codes
6718: ** are of the form [status parameters | SQLITE_STATUS_...].)^
6719: ** ^The current value of the parameter is returned into *pCurrent.
6720: ** ^The highest recorded value is returned in *pHighwater. ^If the
6721: ** resetFlag is true, then the highest record value is reset after
6722: ** *pHighwater is written. ^(Some parameters do not record the highest
6723: ** value. For those parameters
6724: ** nothing is written into *pHighwater and the resetFlag is ignored.)^
6725: ** ^(Other parameters record only the highwater mark and not the current
6726: ** value. For these latter parameters nothing is written into *pCurrent.)^
6727: **
6728: ** ^The sqlite3_status() and sqlite3_status64() routines return
6729: ** SQLITE_OK on success and a non-zero [error code] on failure.
6730: **
6731: ** If either the current value or the highwater mark is too large to
6732: ** be represented by a 32-bit integer, then the values returned by
6733: ** sqlite3_status() are undefined.
6734: **
6735: ** See also: [sqlite3_db_status()]
6736: */
6737: SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
6738: SQLITE_API int sqlite3_status64(
6739: int op,
6740: sqlite3_int64 *pCurrent,
6741: sqlite3_int64 *pHighwater,
6742: int resetFlag
6743: );
6744:
6745:
6746: /*
6747: ** CAPI3REF: Status Parameters
6748: ** KEYWORDS: {status parameters}
6749: **
6750: ** These integer constants designate various run-time status parameters
6751: ** that can be returned by [sqlite3_status()].
6752: **
6753: ** <dl>
6754: ** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
6755: ** <dd>This parameter is the current amount of memory checked out
6756: ** using [sqlite3_malloc()], either directly or indirectly. The
6757: ** figure includes calls made to [sqlite3_malloc()] by the application
6758: ** and internal memory usage by the SQLite library. Scratch memory
6759: ** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache
6760: ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
6761: ** this parameter. The amount returned is the sum of the allocation
6762: ** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
6763: **
6764: ** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
6765: ** <dd>This parameter records the largest memory allocation request
6766: ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
6767: ** internal equivalents). Only the value returned in the
6768: ** *pHighwater parameter to [sqlite3_status()] is of interest.
6769: ** The value written into the *pCurrent parameter is undefined.</dd>)^
6770: **
6771: ** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
6772: ** <dd>This parameter records the number of separate memory allocations
6773: ** currently checked out.</dd>)^
6774: **
6775: ** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
6776: ** <dd>This parameter returns the number of pages used out of the
6777: ** [pagecache memory allocator] that was configured using
6778: ** [SQLITE_CONFIG_PAGECACHE]. The
6779: ** value returned is in pages, not in bytes.</dd>)^
6780: **
6781: ** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]]
6782: ** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
6783: ** <dd>This parameter returns the number of bytes of page cache
6784: ** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
6785: ** buffer and where forced to overflow to [sqlite3_malloc()]. The
6786: ** returned value includes allocations that overflowed because they
6787: ** where too large (they were larger than the "sz" parameter to
6788: ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
6789: ** no space was left in the page cache.</dd>)^
6790: **
6791: ** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
6792: ** <dd>This parameter records the largest memory allocation request
6793: ** handed to [pagecache memory allocator]. Only the value returned in the
6794: ** *pHighwater parameter to [sqlite3_status()] is of interest.
6795: ** The value written into the *pCurrent parameter is undefined.</dd>)^
6796: **
6797: ** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt>
6798: ** <dd>This parameter returns the number of allocations used out of the
6799: ** [scratch memory allocator] configured using
6800: ** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not
6801: ** in bytes. Since a single thread may only have one scratch allocation
6802: ** outstanding at time, this parameter also reports the number of threads
6803: ** using scratch memory at the same time.</dd>)^
6804: **
6805: ** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
6806: ** <dd>This parameter returns the number of bytes of scratch memory
6807: ** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH]
6808: ** buffer and where forced to overflow to [sqlite3_malloc()]. The values
6809: ** returned include overflows because the requested allocation was too
6810: ** larger (that is, because the requested allocation was larger than the
6811: ** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer
6812: ** slots were available.
6813: ** </dd>)^
6814: **
6815: ** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
6816: ** <dd>This parameter records the largest memory allocation request
6817: ** handed to [scratch memory allocator]. Only the value returned in the
6818: ** *pHighwater parameter to [sqlite3_status()] is of interest.
6819: ** The value written into the *pCurrent parameter is undefined.</dd>)^
6820: **
6821: ** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
6822: ** <dd>The *pHighwater parameter records the deepest parser stack.
6823: ** The *pCurrent value is undefined. The *pHighwater value is only
6824: ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
6825: ** </dl>
6826: **
6827: ** New status parameters may be added from time to time.
6828: */
6829: #define SQLITE_STATUS_MEMORY_USED 0
6830: #define SQLITE_STATUS_PAGECACHE_USED 1
6831: #define SQLITE_STATUS_PAGECACHE_OVERFLOW 2
6832: #define SQLITE_STATUS_SCRATCH_USED 3
6833: #define SQLITE_STATUS_SCRATCH_OVERFLOW 4
6834: #define SQLITE_STATUS_MALLOC_SIZE 5
6835: #define SQLITE_STATUS_PARSER_STACK 6
6836: #define SQLITE_STATUS_PAGECACHE_SIZE 7
6837: #define SQLITE_STATUS_SCRATCH_SIZE 8
6838: #define SQLITE_STATUS_MALLOC_COUNT 9
6839:
6840: /*
6841: ** CAPI3REF: Database Connection Status
6842: ** METHOD: sqlite3
6843: **
6844: ** ^This interface is used to retrieve runtime status information
6845: ** about a single [database connection]. ^The first argument is the
6846: ** database connection object to be interrogated. ^The second argument
6847: ** is an integer constant, taken from the set of
6848: ** [SQLITE_DBSTATUS options], that
6849: ** determines the parameter to interrogate. The set of
6850: ** [SQLITE_DBSTATUS options] is likely
6851: ** to grow in future releases of SQLite.
6852: **
6853: ** ^The current value of the requested parameter is written into *pCur
6854: ** and the highest instantaneous value is written into *pHiwtr. ^If
6855: ** the resetFlg is true, then the highest instantaneous value is
6856: ** reset back down to the current value.
6857: **
6858: ** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
6859: ** non-zero [error code] on failure.
6860: **
6861: ** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
6862: */
6863: SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
6864:
6865: /*
6866: ** CAPI3REF: Status Parameters for database connections
6867: ** KEYWORDS: {SQLITE_DBSTATUS options}
6868: **
6869: ** These constants are the available integer "verbs" that can be passed as
6870: ** the second argument to the [sqlite3_db_status()] interface.
6871: **
6872: ** New verbs may be added in future releases of SQLite. Existing verbs
6873: ** might be discontinued. Applications should check the return code from
6874: ** [sqlite3_db_status()] to make sure that the call worked.
6875: ** The [sqlite3_db_status()] interface will return a non-zero error code
6876: ** if a discontinued or unsupported verb is invoked.
6877: **
6878: ** <dl>
6879: ** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
6880: ** <dd>This parameter returns the number of lookaside memory slots currently
6881: ** checked out.</dd>)^
6882: **
6883: ** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
6884: ** <dd>This parameter returns the number malloc attempts that were
6885: ** satisfied using lookaside memory. Only the high-water value is meaningful;
6886: ** the current value is always zero.)^
6887: **
6888: ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]]
6889: ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
6890: ** <dd>This parameter returns the number malloc attempts that might have
6891: ** been satisfied using lookaside memory but failed due to the amount of
6892: ** memory requested being larger than the lookaside slot size.
6893: ** Only the high-water value is meaningful;
6894: ** the current value is always zero.)^
6895: **
6896: ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]]
6897: ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
6898: ** <dd>This parameter returns the number malloc attempts that might have
6899: ** been satisfied using lookaside memory but failed due to all lookaside
6900: ** memory already being in use.
6901: ** Only the high-water value is meaningful;
6902: ** the current value is always zero.)^
6903: **
6904: ** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
6905: ** <dd>This parameter returns the approximate number of bytes of heap
6906: ** memory used by all pager caches associated with the database connection.)^
6907: ** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
6908: **
6909: ** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]]
6910: ** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt>
6911: ** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a
6912: ** pager cache is shared between two or more connections the bytes of heap
6913: ** memory used by that pager cache is divided evenly between the attached
6914: ** connections.)^ In other words, if none of the pager caches associated
6915: ** with the database connection are shared, this request returns the same
6916: ** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are
6917: ** shared, the value returned by this call will be smaller than that returned
6918: ** by DBSTATUS_CACHE_USED. ^The highwater mark associated with
6919: ** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0.
6920: **
6921: ** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
6922: ** <dd>This parameter returns the approximate number of bytes of heap
6923: ** memory used to store the schema for all databases associated
6924: ** with the connection - main, temp, and any [ATTACH]-ed databases.)^
6925: ** ^The full amount of memory used by the schemas is reported, even if the
6926: ** schema memory is shared with other database connections due to
6927: ** [shared cache mode] being enabled.
6928: ** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
6929: **
6930: ** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
6931: ** <dd>This parameter returns the approximate number of bytes of heap
6932: ** and lookaside memory used by all prepared statements associated with
6933: ** the database connection.)^
6934: ** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
6935: ** </dd>
6936: **
6937: ** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt>
6938: ** <dd>This parameter returns the number of pager cache hits that have
6939: ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT
6940: ** is always 0.
6941: ** </dd>
6942: **
6943: ** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt>
6944: ** <dd>This parameter returns the number of pager cache misses that have
6945: ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS
6946: ** is always 0.
6947: ** </dd>
6948: **
6949: ** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt>
6950: ** <dd>This parameter returns the number of dirty cache entries that have
6951: ** been written to disk. Specifically, the number of pages written to the
6952: ** wal file in wal mode databases, or the number of pages written to the
6953: ** database file in rollback mode databases. Any pages written as part of
6954: ** transaction rollback or database recovery operations are not included.
6955: ** If an IO or other error occurs while writing a page to disk, the effect
6956: ** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The
6957: ** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0.
6958: ** </dd>
6959: **
6960: ** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt>
6961: ** <dd>This parameter returns zero for the current value if and only if
6962: ** all foreign key constraints (deferred or immediate) have been
6963: ** resolved.)^ ^The highwater mark is always 0.
6964: ** </dd>
6965: ** </dl>
6966: */
6967: #define SQLITE_DBSTATUS_LOOKASIDE_USED 0
6968: #define SQLITE_DBSTATUS_CACHE_USED 1
6969: #define SQLITE_DBSTATUS_SCHEMA_USED 2
6970: #define SQLITE_DBSTATUS_STMT_USED 3
6971: #define SQLITE_DBSTATUS_LOOKASIDE_HIT 4
6972: #define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5
6973: #define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6
6974: #define SQLITE_DBSTATUS_CACHE_HIT 7
6975: #define SQLITE_DBSTATUS_CACHE_MISS 8
6976: #define SQLITE_DBSTATUS_CACHE_WRITE 9
6977: #define SQLITE_DBSTATUS_DEFERRED_FKS 10
6978: #define SQLITE_DBSTATUS_CACHE_USED_SHARED 11
6979: #define SQLITE_DBSTATUS_MAX 11 /* Largest defined DBSTATUS */
6980:
6981:
6982: /*
6983: ** CAPI3REF: Prepared Statement Status
6984: ** METHOD: sqlite3_stmt
6985: **
6986: ** ^(Each prepared statement maintains various
6987: ** [SQLITE_STMTSTATUS counters] that measure the number
6988: ** of times it has performed specific operations.)^ These counters can
6989: ** be used to monitor the performance characteristics of the prepared
6990: ** statements. For example, if the number of table steps greatly exceeds
6991: ** the number of table searches or result rows, that would tend to indicate
6992: ** that the prepared statement is using a full table scan rather than
6993: ** an index.
6994: **
6995: ** ^(This interface is used to retrieve and reset counter values from
6996: ** a [prepared statement]. The first argument is the prepared statement
6997: ** object to be interrogated. The second argument
6998: ** is an integer code for a specific [SQLITE_STMTSTATUS counter]
6999: ** to be interrogated.)^
7000: ** ^The current value of the requested counter is returned.
7001: ** ^If the resetFlg is true, then the counter is reset to zero after this
7002: ** interface call returns.
7003: **
7004: ** See also: [sqlite3_status()] and [sqlite3_db_status()].
7005: */
7006: SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
7007:
7008: /*
7009: ** CAPI3REF: Status Parameters for prepared statements
7010: ** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters}
7011: **
7012: ** These preprocessor macros define integer codes that name counter
7013: ** values associated with the [sqlite3_stmt_status()] interface.
7014: ** The meanings of the various counters are as follows:
7015: **
7016: ** <dl>
7017: ** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
7018: ** <dd>^This is the number of times that SQLite has stepped forward in
7019: ** a table as part of a full table scan. Large numbers for this counter
7020: ** may indicate opportunities for performance improvement through
7021: ** careful use of indices.</dd>
7022: **
7023: ** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt>
7024: ** <dd>^This is the number of sort operations that have occurred.
7025: ** A non-zero value in this counter may indicate an opportunity to
7026: ** improvement performance through careful use of indices.</dd>
7027: **
7028: ** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
7029: ** <dd>^This is the number of rows inserted into transient indices that
7030: ** were created automatically in order to help joins run faster.
7031: ** A non-zero value in this counter may indicate an opportunity to
7032: ** improvement performance by adding permanent indices that do not
7033: ** need to be reinitialized each time the statement is run.</dd>
7034: **
7035: ** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt>
7036: ** <dd>^This is the number of virtual machine operations executed
7037: ** by the prepared statement if that number is less than or equal
7038: ** to 2147483647. The number of virtual machine operations can be
7039: ** used as a proxy for the total work done by the prepared statement.
7040: ** If the number of virtual machine operations exceeds 2147483647
7041: ** then the value returned by this statement status code is undefined.
7042: ** </dd>
7043: ** </dl>
7044: */
7045: #define SQLITE_STMTSTATUS_FULLSCAN_STEP 1
7046: #define SQLITE_STMTSTATUS_SORT 2
7047: #define SQLITE_STMTSTATUS_AUTOINDEX 3
7048: #define SQLITE_STMTSTATUS_VM_STEP 4
7049:
7050: /*
7051: ** CAPI3REF: Custom Page Cache Object
7052: **
7053: ** The sqlite3_pcache type is opaque. It is implemented by
7054: ** the pluggable module. The SQLite core has no knowledge of
7055: ** its size or internal structure and never deals with the
7056: ** sqlite3_pcache object except by holding and passing pointers
7057: ** to the object.
7058: **
7059: ** See [sqlite3_pcache_methods2] for additional information.
7060: */
7061: typedef struct sqlite3_pcache sqlite3_pcache;
7062:
7063: /*
7064: ** CAPI3REF: Custom Page Cache Object
7065: **
7066: ** The sqlite3_pcache_page object represents a single page in the
7067: ** page cache. The page cache will allocate instances of this
7068: ** object. Various methods of the page cache use pointers to instances
7069: ** of this object as parameters or as their return value.
7070: **
7071: ** See [sqlite3_pcache_methods2] for additional information.
7072: */
7073: typedef struct sqlite3_pcache_page sqlite3_pcache_page;
7074: struct sqlite3_pcache_page {
7075: void *pBuf; /* The content of the page */
7076: void *pExtra; /* Extra information associated with the page */
7077: };
7078:
7079: /*
7080: ** CAPI3REF: Application Defined Page Cache.
7081: ** KEYWORDS: {page cache}
7082: **
7083: ** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can
7084: ** register an alternative page cache implementation by passing in an
7085: ** instance of the sqlite3_pcache_methods2 structure.)^
7086: ** In many applications, most of the heap memory allocated by
7087: ** SQLite is used for the page cache.
7088: ** By implementing a
7089: ** custom page cache using this API, an application can better control
7090: ** the amount of memory consumed by SQLite, the way in which
7091: ** that memory is allocated and released, and the policies used to
7092: ** determine exactly which parts of a database file are cached and for
7093: ** how long.
7094: **
7095: ** The alternative page cache mechanism is an
7096: ** extreme measure that is only needed by the most demanding applications.
7097: ** The built-in page cache is recommended for most uses.
7098: **
7099: ** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an
7100: ** internal buffer by SQLite within the call to [sqlite3_config]. Hence
7101: ** the application may discard the parameter after the call to
7102: ** [sqlite3_config()] returns.)^
7103: **
7104: ** [[the xInit() page cache method]]
7105: ** ^(The xInit() method is called once for each effective
7106: ** call to [sqlite3_initialize()])^
7107: ** (usually only once during the lifetime of the process). ^(The xInit()
7108: ** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^
7109: ** The intent of the xInit() method is to set up global data structures
7110: ** required by the custom page cache implementation.
7111: ** ^(If the xInit() method is NULL, then the
7112: ** built-in default page cache is used instead of the application defined
7113: ** page cache.)^
7114: **
7115: ** [[the xShutdown() page cache method]]
7116: ** ^The xShutdown() method is called by [sqlite3_shutdown()].
7117: ** It can be used to clean up
7118: ** any outstanding resources before process shutdown, if required.
7119: ** ^The xShutdown() method may be NULL.
7120: **
7121: ** ^SQLite automatically serializes calls to the xInit method,
7122: ** so the xInit method need not be threadsafe. ^The
7123: ** xShutdown method is only called from [sqlite3_shutdown()] so it does
7124: ** not need to be threadsafe either. All other methods must be threadsafe
7125: ** in multithreaded applications.
7126: **
7127: ** ^SQLite will never invoke xInit() more than once without an intervening
7128: ** call to xShutdown().
7129: **
7130: ** [[the xCreate() page cache methods]]
7131: ** ^SQLite invokes the xCreate() method to construct a new cache instance.
7132: ** SQLite will typically create one cache instance for each open database file,
7133: ** though this is not guaranteed. ^The
7134: ** first parameter, szPage, is the size in bytes of the pages that must
7135: ** be allocated by the cache. ^szPage will always a power of two. ^The
7136: ** second parameter szExtra is a number of bytes of extra storage
7137: ** associated with each page cache entry. ^The szExtra parameter will
7138: ** a number less than 250. SQLite will use the
7139: ** extra szExtra bytes on each page to store metadata about the underlying
7140: ** database page on disk. The value passed into szExtra depends
7141: ** on the SQLite version, the target platform, and how SQLite was compiled.
7142: ** ^The third argument to xCreate(), bPurgeable, is true if the cache being
7143: ** created will be used to cache database pages of a file stored on disk, or
7144: ** false if it is used for an in-memory database. The cache implementation
7145: ** does not have to do anything special based with the value of bPurgeable;
7146: ** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will
7147: ** never invoke xUnpin() except to deliberately delete a page.
7148: ** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
7149: ** false will always have the "discard" flag set to true.
7150: ** ^Hence, a cache created with bPurgeable false will
7151: ** never contain any unpinned pages.
7152: **
7153: ** [[the xCachesize() page cache method]]
7154: ** ^(The xCachesize() method may be called at any time by SQLite to set the
7155: ** suggested maximum cache-size (number of pages stored by) the cache
7156: ** instance passed as the first argument. This is the value configured using
7157: ** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable
7158: ** parameter, the implementation is not required to do anything with this
7159: ** value; it is advisory only.
7160: **
7161: ** [[the xPagecount() page cache methods]]
7162: ** The xPagecount() method must return the number of pages currently
7163: ** stored in the cache, both pinned and unpinned.
7164: **
7165: ** [[the xFetch() page cache methods]]
7166: ** The xFetch() method locates a page in the cache and returns a pointer to
7167: ** an sqlite3_pcache_page object associated with that page, or a NULL pointer.
7168: ** The pBuf element of the returned sqlite3_pcache_page object will be a
7169: ** pointer to a buffer of szPage bytes used to store the content of a
7170: ** single database page. The pExtra element of sqlite3_pcache_page will be
7171: ** a pointer to the szExtra bytes of extra storage that SQLite has requested
7172: ** for each entry in the page cache.
7173: **
7174: ** The page to be fetched is determined by the key. ^The minimum key value
7175: ** is 1. After it has been retrieved using xFetch, the page is considered
7176: ** to be "pinned".
7177: **
7178: ** If the requested page is already in the page cache, then the page cache
7179: ** implementation must return a pointer to the page buffer with its content
7180: ** intact. If the requested page is not already in the cache, then the
7181: ** cache implementation should use the value of the createFlag
7182: ** parameter to help it determined what action to take:
7183: **
7184: ** <table border=1 width=85% align=center>
7185: ** <tr><th> createFlag <th> Behavior when page is not already in cache
7186: ** <tr><td> 0 <td> Do not allocate a new page. Return NULL.
7187: ** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
7188: ** Otherwise return NULL.
7189: ** <tr><td> 2 <td> Make every effort to allocate a new page. Only return
7190: ** NULL if allocating a new page is effectively impossible.
7191: ** </table>
7192: **
7193: ** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite
7194: ** will only use a createFlag of 2 after a prior call with a createFlag of 1
7195: ** failed.)^ In between the to xFetch() calls, SQLite may
7196: ** attempt to unpin one or more cache pages by spilling the content of
7197: ** pinned pages to disk and synching the operating system disk cache.
7198: **
7199: ** [[the xUnpin() page cache method]]
7200: ** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
7201: ** as its second argument. If the third parameter, discard, is non-zero,
7202: ** then the page must be evicted from the cache.
7203: ** ^If the discard parameter is
7204: ** zero, then the page may be discarded or retained at the discretion of
7205: ** page cache implementation. ^The page cache implementation
7206: ** may choose to evict unpinned pages at any time.
7207: **
7208: ** The cache must not perform any reference counting. A single
7209: ** call to xUnpin() unpins the page regardless of the number of prior calls
7210: ** to xFetch().
7211: **
7212: ** [[the xRekey() page cache methods]]
7213: ** The xRekey() method is used to change the key value associated with the
7214: ** page passed as the second argument. If the cache
7215: ** previously contains an entry associated with newKey, it must be
7216: ** discarded. ^Any prior cache entry associated with newKey is guaranteed not
7217: ** to be pinned.
7218: **
7219: ** When SQLite calls the xTruncate() method, the cache must discard all
7220: ** existing cache entries with page numbers (keys) greater than or equal
7221: ** to the value of the iLimit parameter passed to xTruncate(). If any
7222: ** of these pages are pinned, they are implicitly unpinned, meaning that
7223: ** they can be safely discarded.
7224: **
7225: ** [[the xDestroy() page cache method]]
7226: ** ^The xDestroy() method is used to delete a cache allocated by xCreate().
7227: ** All resources associated with the specified cache should be freed. ^After
7228: ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
7229: ** handle invalid, and will not use it with any other sqlite3_pcache_methods2
7230: ** functions.
7231: **
7232: ** [[the xShrink() page cache method]]
7233: ** ^SQLite invokes the xShrink() method when it wants the page cache to
7234: ** free up as much of heap memory as possible. The page cache implementation
7235: ** is not obligated to free any memory, but well-behaved implementations should
7236: ** do their best.
7237: */
7238: typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
7239: struct sqlite3_pcache_methods2 {
7240: int iVersion;
7241: void *pArg;
7242: int (*xInit)(void*);
7243: void (*xShutdown)(void*);
7244: sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
7245: void (*xCachesize)(sqlite3_pcache*, int nCachesize);
7246: int (*xPagecount)(sqlite3_pcache*);
7247: sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
7248: void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
7249: void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*,
7250: unsigned oldKey, unsigned newKey);
7251: void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
7252: void (*xDestroy)(sqlite3_pcache*);
7253: void (*xShrink)(sqlite3_pcache*);
7254: };
7255:
7256: /*
7257: ** This is the obsolete pcache_methods object that has now been replaced
7258: ** by sqlite3_pcache_methods2. This object is not used by SQLite. It is
7259: ** retained in the header file for backwards compatibility only.
7260: */
7261: typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
7262: struct sqlite3_pcache_methods {
7263: void *pArg;
7264: int (*xInit)(void*);
7265: void (*xShutdown)(void*);
7266: sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
7267: void (*xCachesize)(sqlite3_pcache*, int nCachesize);
7268: int (*xPagecount)(sqlite3_pcache*);
7269: void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
7270: void (*xUnpin)(sqlite3_pcache*, void*, int discard);
7271: void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
7272: void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
7273: void (*xDestroy)(sqlite3_pcache*);
7274: };
7275:
7276:
7277: /*
7278: ** CAPI3REF: Online Backup Object
7279: **
7280: ** The sqlite3_backup object records state information about an ongoing
7281: ** online backup operation. ^The sqlite3_backup object is created by
7282: ** a call to [sqlite3_backup_init()] and is destroyed by a call to
7283: ** [sqlite3_backup_finish()].
7284: **
7285: ** See Also: [Using the SQLite Online Backup API]
7286: */
7287: typedef struct sqlite3_backup sqlite3_backup;
7288:
7289: /*
7290: ** CAPI3REF: Online Backup API.
7291: **
7292: ** The backup API copies the content of one database into another.
7293: ** It is useful either for creating backups of databases or
7294: ** for copying in-memory databases to or from persistent files.
7295: **
7296: ** See Also: [Using the SQLite Online Backup API]
7297: **
7298: ** ^SQLite holds a write transaction open on the destination database file
7299: ** for the duration of the backup operation.
7300: ** ^The source database is read-locked only while it is being read;
7301: ** it is not locked continuously for the entire backup operation.
7302: ** ^Thus, the backup may be performed on a live source database without
7303: ** preventing other database connections from
7304: ** reading or writing to the source database while the backup is underway.
7305: **
7306: ** ^(To perform a backup operation:
7307: ** <ol>
7308: ** <li><b>sqlite3_backup_init()</b> is called once to initialize the
7309: ** backup,
7310: ** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
7311: ** the data between the two databases, and finally
7312: ** <li><b>sqlite3_backup_finish()</b> is called to release all resources
7313: ** associated with the backup operation.
7314: ** </ol>)^
7315: ** There should be exactly one call to sqlite3_backup_finish() for each
7316: ** successful call to sqlite3_backup_init().
7317: **
7318: ** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
7319: **
7320: ** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
7321: ** [database connection] associated with the destination database
7322: ** and the database name, respectively.
7323: ** ^The database name is "main" for the main database, "temp" for the
7324: ** temporary database, or the name specified after the AS keyword in
7325: ** an [ATTACH] statement for an attached database.
7326: ** ^The S and M arguments passed to
7327: ** sqlite3_backup_init(D,N,S,M) identify the [database connection]
7328: ** and database name of the source database, respectively.
7329: ** ^The source and destination [database connections] (parameters S and D)
7330: ** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
7331: ** an error.
7332: **
7333: ** ^A call to sqlite3_backup_init() will fail, returning NULL, if
7334: ** there is already a read or read-write transaction open on the
7335: ** destination database.
7336: **
7337: ** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
7338: ** returned and an error code and error message are stored in the
7339: ** destination [database connection] D.
7340: ** ^The error code and message for the failed call to sqlite3_backup_init()
7341: ** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
7342: ** [sqlite3_errmsg16()] functions.
7343: ** ^A successful call to sqlite3_backup_init() returns a pointer to an
7344: ** [sqlite3_backup] object.
7345: ** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
7346: ** sqlite3_backup_finish() functions to perform the specified backup
7347: ** operation.
7348: **
7349: ** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
7350: **
7351: ** ^Function sqlite3_backup_step(B,N) will copy up to N pages between
7352: ** the source and destination databases specified by [sqlite3_backup] object B.
7353: ** ^If N is negative, all remaining source pages are copied.
7354: ** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
7355: ** are still more pages to be copied, then the function returns [SQLITE_OK].
7356: ** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
7357: ** from source to destination, then it returns [SQLITE_DONE].
7358: ** ^If an error occurs while running sqlite3_backup_step(B,N),
7359: ** then an [error code] is returned. ^As well as [SQLITE_OK] and
7360: ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
7361: ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
7362: ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
7363: **
7364: ** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
7365: ** <ol>
7366: ** <li> the destination database was opened read-only, or
7367: ** <li> the destination database is using write-ahead-log journaling
7368: ** and the destination and source page sizes differ, or
7369: ** <li> the destination database is an in-memory database and the
7370: ** destination and source page sizes differ.
7371: ** </ol>)^
7372: **
7373: ** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
7374: ** the [sqlite3_busy_handler | busy-handler function]
7375: ** is invoked (if one is specified). ^If the
7376: ** busy-handler returns non-zero before the lock is available, then
7377: ** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
7378: ** sqlite3_backup_step() can be retried later. ^If the source
7379: ** [database connection]
7380: ** is being used to write to the source database when sqlite3_backup_step()
7381: ** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
7382: ** case the call to sqlite3_backup_step() can be retried later on. ^(If
7383: ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
7384: ** [SQLITE_READONLY] is returned, then
7385: ** there is no point in retrying the call to sqlite3_backup_step(). These
7386: ** errors are considered fatal.)^ The application must accept
7387: ** that the backup operation has failed and pass the backup operation handle
7388: ** to the sqlite3_backup_finish() to release associated resources.
7389: **
7390: ** ^The first call to sqlite3_backup_step() obtains an exclusive lock
7391: ** on the destination file. ^The exclusive lock is not released until either
7392: ** sqlite3_backup_finish() is called or the backup operation is complete
7393: ** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to
7394: ** sqlite3_backup_step() obtains a [shared lock] on the source database that
7395: ** lasts for the duration of the sqlite3_backup_step() call.
7396: ** ^Because the source database is not locked between calls to
7397: ** sqlite3_backup_step(), the source database may be modified mid-way
7398: ** through the backup process. ^If the source database is modified by an
7399: ** external process or via a database connection other than the one being
7400: ** used by the backup operation, then the backup will be automatically
7401: ** restarted by the next call to sqlite3_backup_step(). ^If the source
7402: ** database is modified by the using the same database connection as is used
7403: ** by the backup operation, then the backup database is automatically
7404: ** updated at the same time.
7405: **
7406: ** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
7407: **
7408: ** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the
7409: ** application wishes to abandon the backup operation, the application
7410: ** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
7411: ** ^The sqlite3_backup_finish() interfaces releases all
7412: ** resources associated with the [sqlite3_backup] object.
7413: ** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
7414: ** active write-transaction on the destination database is rolled back.
7415: ** The [sqlite3_backup] object is invalid
7416: ** and may not be used following a call to sqlite3_backup_finish().
7417: **
7418: ** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
7419: ** sqlite3_backup_step() errors occurred, regardless or whether or not
7420: ** sqlite3_backup_step() completed.
7421: ** ^If an out-of-memory condition or IO error occurred during any prior
7422: ** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
7423: ** sqlite3_backup_finish() returns the corresponding [error code].
7424: **
7425: ** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
7426: ** is not a permanent error and does not affect the return value of
7427: ** sqlite3_backup_finish().
7428: **
7429: ** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]]
7430: ** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
7431: **
7432: ** ^The sqlite3_backup_remaining() routine returns the number of pages still
7433: ** to be backed up at the conclusion of the most recent sqlite3_backup_step().
7434: ** ^The sqlite3_backup_pagecount() routine returns the total number of pages
7435: ** in the source database at the conclusion of the most recent
7436: ** sqlite3_backup_step().
7437: ** ^(The values returned by these functions are only updated by
7438: ** sqlite3_backup_step(). If the source database is modified in a way that
7439: ** changes the size of the source database or the number of pages remaining,
7440: ** those changes are not reflected in the output of sqlite3_backup_pagecount()
7441: ** and sqlite3_backup_remaining() until after the next
7442: ** sqlite3_backup_step().)^
7443: **
7444: ** <b>Concurrent Usage of Database Handles</b>
7445: **
7446: ** ^The source [database connection] may be used by the application for other
7447: ** purposes while a backup operation is underway or being initialized.
7448: ** ^If SQLite is compiled and configured to support threadsafe database
7449: ** connections, then the source database connection may be used concurrently
7450: ** from within other threads.
7451: **
7452: ** However, the application must guarantee that the destination
7453: ** [database connection] is not passed to any other API (by any thread) after
7454: ** sqlite3_backup_init() is called and before the corresponding call to
7455: ** sqlite3_backup_finish(). SQLite does not currently check to see
7456: ** if the application incorrectly accesses the destination [database connection]
7457: ** and so no error code is reported, but the operations may malfunction
7458: ** nevertheless. Use of the destination database connection while a
7459: ** backup is in progress might also also cause a mutex deadlock.
7460: **
7461: ** If running in [shared cache mode], the application must
7462: ** guarantee that the shared cache used by the destination database
7463: ** is not accessed while the backup is running. In practice this means
7464: ** that the application must guarantee that the disk file being
7465: ** backed up to is not accessed by any connection within the process,
7466: ** not just the specific connection that was passed to sqlite3_backup_init().
7467: **
7468: ** The [sqlite3_backup] object itself is partially threadsafe. Multiple
7469: ** threads may safely make multiple concurrent calls to sqlite3_backup_step().
7470: ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
7471: ** APIs are not strictly speaking threadsafe. If they are invoked at the
7472: ** same time as another thread is invoking sqlite3_backup_step() it is
7473: ** possible that they return invalid values.
7474: */
7475: SQLITE_API sqlite3_backup *sqlite3_backup_init(
7476: sqlite3 *pDest, /* Destination database handle */
7477: const char *zDestName, /* Destination database name */
7478: sqlite3 *pSource, /* Source database handle */
7479: const char *zSourceName /* Source database name */
7480: );
7481: SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage);
7482: SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p);
7483: SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p);
7484: SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p);
7485:
7486: /*
7487: ** CAPI3REF: Unlock Notification
7488: ** METHOD: sqlite3
7489: **
7490: ** ^When running in shared-cache mode, a database operation may fail with
7491: ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
7492: ** individual tables within the shared-cache cannot be obtained. See
7493: ** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
7494: ** ^This API may be used to register a callback that SQLite will invoke
7495: ** when the connection currently holding the required lock relinquishes it.
7496: ** ^This API is only available if the library was compiled with the
7497: ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
7498: **
7499: ** See Also: [Using the SQLite Unlock Notification Feature].
7500: **
7501: ** ^Shared-cache locks are released when a database connection concludes
7502: ** its current transaction, either by committing it or rolling it back.
7503: **
7504: ** ^When a connection (known as the blocked connection) fails to obtain a
7505: ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
7506: ** identity of the database connection (the blocking connection) that
7507: ** has locked the required resource is stored internally. ^After an
7508: ** application receives an SQLITE_LOCKED error, it may call the
7509: ** sqlite3_unlock_notify() method with the blocked connection handle as
7510: ** the first argument to register for a callback that will be invoked
7511: ** when the blocking connections current transaction is concluded. ^The
7512: ** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
7513: ** call that concludes the blocking connections transaction.
7514: **
7515: ** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
7516: ** there is a chance that the blocking connection will have already
7517: ** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
7518: ** If this happens, then the specified callback is invoked immediately,
7519: ** from within the call to sqlite3_unlock_notify().)^
7520: **
7521: ** ^If the blocked connection is attempting to obtain a write-lock on a
7522: ** shared-cache table, and more than one other connection currently holds
7523: ** a read-lock on the same table, then SQLite arbitrarily selects one of
7524: ** the other connections to use as the blocking connection.
7525: **
7526: ** ^(There may be at most one unlock-notify callback registered by a
7527: ** blocked connection. If sqlite3_unlock_notify() is called when the
7528: ** blocked connection already has a registered unlock-notify callback,
7529: ** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
7530: ** called with a NULL pointer as its second argument, then any existing
7531: ** unlock-notify callback is canceled. ^The blocked connections
7532: ** unlock-notify callback may also be canceled by closing the blocked
7533: ** connection using [sqlite3_close()].
7534: **
7535: ** The unlock-notify callback is not reentrant. If an application invokes
7536: ** any sqlite3_xxx API functions from within an unlock-notify callback, a
7537: ** crash or deadlock may be the result.
7538: **
7539: ** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
7540: ** returns SQLITE_OK.
7541: **
7542: ** <b>Callback Invocation Details</b>
7543: **
7544: ** When an unlock-notify callback is registered, the application provides a
7545: ** single void* pointer that is passed to the callback when it is invoked.
7546: ** However, the signature of the callback function allows SQLite to pass
7547: ** it an array of void* context pointers. The first argument passed to
7548: ** an unlock-notify callback is a pointer to an array of void* pointers,
7549: ** and the second is the number of entries in the array.
7550: **
7551: ** When a blocking connections transaction is concluded, there may be
7552: ** more than one blocked connection that has registered for an unlock-notify
7553: ** callback. ^If two or more such blocked connections have specified the
7554: ** same callback function, then instead of invoking the callback function
7555: ** multiple times, it is invoked once with the set of void* context pointers
7556: ** specified by the blocked connections bundled together into an array.
7557: ** This gives the application an opportunity to prioritize any actions
7558: ** related to the set of unblocked database connections.
7559: **
7560: ** <b>Deadlock Detection</b>
7561: **
7562: ** Assuming that after registering for an unlock-notify callback a
7563: ** database waits for the callback to be issued before taking any further
7564: ** action (a reasonable assumption), then using this API may cause the
7565: ** application to deadlock. For example, if connection X is waiting for
7566: ** connection Y's transaction to be concluded, and similarly connection
7567: ** Y is waiting on connection X's transaction, then neither connection
7568: ** will proceed and the system may remain deadlocked indefinitely.
7569: **
7570: ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
7571: ** detection. ^If a given call to sqlite3_unlock_notify() would put the
7572: ** system in a deadlocked state, then SQLITE_LOCKED is returned and no
7573: ** unlock-notify callback is registered. The system is said to be in
7574: ** a deadlocked state if connection A has registered for an unlock-notify
7575: ** callback on the conclusion of connection B's transaction, and connection
7576: ** B has itself registered for an unlock-notify callback when connection
7577: ** A's transaction is concluded. ^Indirect deadlock is also detected, so
7578: ** the system is also considered to be deadlocked if connection B has
7579: ** registered for an unlock-notify callback on the conclusion of connection
7580: ** C's transaction, where connection C is waiting on connection A. ^Any
7581: ** number of levels of indirection are allowed.
7582: **
7583: ** <b>The "DROP TABLE" Exception</b>
7584: **
7585: ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost
7586: ** always appropriate to call sqlite3_unlock_notify(). There is however,
7587: ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
7588: ** SQLite checks if there are any currently executing SELECT statements
7589: ** that belong to the same connection. If there are, SQLITE_LOCKED is
7590: ** returned. In this case there is no "blocking connection", so invoking
7591: ** sqlite3_unlock_notify() results in the unlock-notify callback being
7592: ** invoked immediately. If the application then re-attempts the "DROP TABLE"
7593: ** or "DROP INDEX" query, an infinite loop might be the result.
7594: **
7595: ** One way around this problem is to check the extended error code returned
7596: ** by an sqlite3_step() call. ^(If there is a blocking connection, then the
7597: ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
7598: ** the special "DROP TABLE/INDEX" case, the extended error code is just
7599: ** SQLITE_LOCKED.)^
7600: */
7601: SQLITE_API int sqlite3_unlock_notify(
7602: sqlite3 *pBlocked, /* Waiting connection */
7603: void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */
7604: void *pNotifyArg /* Argument to pass to xNotify */
7605: );
7606:
7607:
7608: /*
7609: ** CAPI3REF: String Comparison
7610: **
7611: ** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications
7612: ** and extensions to compare the contents of two buffers containing UTF-8
7613: ** strings in a case-independent fashion, using the same definition of "case
7614: ** independence" that SQLite uses internally when comparing identifiers.
7615: */
7616: SQLITE_API int sqlite3_stricmp(const char *, const char *);
7617: SQLITE_API int sqlite3_strnicmp(const char *, const char *, int);
7618:
7619: /*
7620: ** CAPI3REF: String Globbing
7621: *
7622: ** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if
7623: ** string X matches the [GLOB] pattern P.
7624: ** ^The definition of [GLOB] pattern matching used in
7625: ** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the
7626: ** SQL dialect understood by SQLite. ^The [sqlite3_strglob(P,X)] function
7627: ** is case sensitive.
7628: **
7629: ** Note that this routine returns zero on a match and non-zero if the strings
7630: ** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
7631: **
7632: ** See also: [sqlite3_strlike()].
7633: */
7634: SQLITE_API int sqlite3_strglob(const char *zGlob, const char *zStr);
7635:
7636: /*
7637: ** CAPI3REF: String LIKE Matching
7638: *
7639: ** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if
7640: ** string X matches the [LIKE] pattern P with escape character E.
7641: ** ^The definition of [LIKE] pattern matching used in
7642: ** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E"
7643: ** operator in the SQL dialect understood by SQLite. ^For "X LIKE P" without
7644: ** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0.
7645: ** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case
7646: ** insensitive - equivalent upper and lower case ASCII characters match
7647: ** one another.
7648: **
7649: ** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though
7650: ** only ASCII characters are case folded.
7651: **
7652: ** Note that this routine returns zero on a match and non-zero if the strings
7653: ** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
7654: **
7655: ** See also: [sqlite3_strglob()].
7656: */
7657: SQLITE_API int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc);
7658:
7659: /*
7660: ** CAPI3REF: Error Logging Interface
7661: **
7662: ** ^The [sqlite3_log()] interface writes a message into the [error log]
7663: ** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
7664: ** ^If logging is enabled, the zFormat string and subsequent arguments are
7665: ** used with [sqlite3_snprintf()] to generate the final output string.
7666: **
7667: ** The sqlite3_log() interface is intended for use by extensions such as
7668: ** virtual tables, collating functions, and SQL functions. While there is
7669: ** nothing to prevent an application from calling sqlite3_log(), doing so
7670: ** is considered bad form.
7671: **
7672: ** The zFormat string must not be NULL.
7673: **
7674: ** To avoid deadlocks and other threading problems, the sqlite3_log() routine
7675: ** will not use dynamically allocated memory. The log message is stored in
7676: ** a fixed-length buffer on the stack. If the log message is longer than
7677: ** a few hundred characters, it will be truncated to the length of the
7678: ** buffer.
7679: */
7680: SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...);
7681:
7682: /*
7683: ** CAPI3REF: Write-Ahead Log Commit Hook
7684: ** METHOD: sqlite3
7685: **
7686: ** ^The [sqlite3_wal_hook()] function is used to register a callback that
7687: ** is invoked each time data is committed to a database in wal mode.
7688: **
7689: ** ^(The callback is invoked by SQLite after the commit has taken place and
7690: ** the associated write-lock on the database released)^, so the implementation
7691: ** may read, write or [checkpoint] the database as required.
7692: **
7693: ** ^The first parameter passed to the callback function when it is invoked
7694: ** is a copy of the third parameter passed to sqlite3_wal_hook() when
7695: ** registering the callback. ^The second is a copy of the database handle.
7696: ** ^The third parameter is the name of the database that was written to -
7697: ** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
7698: ** is the number of pages currently in the write-ahead log file,
7699: ** including those that were just committed.
7700: **
7701: ** The callback function should normally return [SQLITE_OK]. ^If an error
7702: ** code is returned, that error will propagate back up through the
7703: ** SQLite code base to cause the statement that provoked the callback
7704: ** to report an error, though the commit will have still occurred. If the
7705: ** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
7706: ** that does not correspond to any valid SQLite error code, the results
7707: ** are undefined.
7708: **
7709: ** A single database handle may have at most a single write-ahead log callback
7710: ** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
7711: ** previously registered write-ahead log callback. ^Note that the
7712: ** [sqlite3_wal_autocheckpoint()] interface and the
7713: ** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
7714: ** overwrite any prior [sqlite3_wal_hook()] settings.
7715: */
7716: SQLITE_API void *sqlite3_wal_hook(
7717: sqlite3*,
7718: int(*)(void *,sqlite3*,const char*,int),
7719: void*
7720: );
7721:
7722: /*
7723: ** CAPI3REF: Configure an auto-checkpoint
7724: ** METHOD: sqlite3
7725: **
7726: ** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
7727: ** [sqlite3_wal_hook()] that causes any database on [database connection] D
7728: ** to automatically [checkpoint]
7729: ** after committing a transaction if there are N or
7730: ** more frames in the [write-ahead log] file. ^Passing zero or
7731: ** a negative value as the nFrame parameter disables automatic
7732: ** checkpoints entirely.
7733: **
7734: ** ^The callback registered by this function replaces any existing callback
7735: ** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback
7736: ** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
7737: ** configured by this function.
7738: **
7739: ** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
7740: ** from SQL.
7741: **
7742: ** ^Checkpoints initiated by this mechanism are
7743: ** [sqlite3_wal_checkpoint_v2|PASSIVE].
7744: **
7745: ** ^Every new [database connection] defaults to having the auto-checkpoint
7746: ** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
7747: ** pages. The use of this interface
7748: ** is only necessary if the default setting is found to be suboptimal
7749: ** for a particular application.
7750: */
7751: SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
7752:
7753: /*
7754: ** CAPI3REF: Checkpoint a database
7755: ** METHOD: sqlite3
7756: **
7757: ** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to
7758: ** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^
7759: **
7760: ** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the
7761: ** [write-ahead log] for database X on [database connection] D to be
7762: ** transferred into the database file and for the write-ahead log to
7763: ** be reset. See the [checkpointing] documentation for addition
7764: ** information.
7765: **
7766: ** This interface used to be the only way to cause a checkpoint to
7767: ** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()]
7768: ** interface was added. This interface is retained for backwards
7769: ** compatibility and as a convenience for applications that need to manually
7770: ** start a callback but which do not need the full power (and corresponding
7771: ** complication) of [sqlite3_wal_checkpoint_v2()].
7772: */
7773: SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
7774:
7775: /*
7776: ** CAPI3REF: Checkpoint a database
7777: ** METHOD: sqlite3
7778: **
7779: ** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint
7780: ** operation on database X of [database connection] D in mode M. Status
7781: ** information is written back into integers pointed to by L and C.)^
7782: ** ^(The M parameter must be a valid [checkpoint mode]:)^
7783: **
7784: ** <dl>
7785: ** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
7786: ** ^Checkpoint as many frames as possible without waiting for any database
7787: ** readers or writers to finish, then sync the database file if all frames
7788: ** in the log were checkpointed. ^The [busy-handler callback]
7789: ** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode.
7790: ** ^On the other hand, passive mode might leave the checkpoint unfinished
7791: ** if there are concurrent readers or writers.
7792: **
7793: ** <dt>SQLITE_CHECKPOINT_FULL<dd>
7794: ** ^This mode blocks (it invokes the
7795: ** [sqlite3_busy_handler|busy-handler callback]) until there is no
7796: ** database writer and all readers are reading from the most recent database
7797: ** snapshot. ^It then checkpoints all frames in the log file and syncs the
7798: ** database file. ^This mode blocks new database writers while it is pending,
7799: ** but new database readers are allowed to continue unimpeded.
7800: **
7801: ** <dt>SQLITE_CHECKPOINT_RESTART<dd>
7802: ** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition
7803: ** that after checkpointing the log file it blocks (calls the
7804: ** [busy-handler callback])
7805: ** until all readers are reading from the database file only. ^This ensures
7806: ** that the next writer will restart the log file from the beginning.
7807: ** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new
7808: ** database writer attempts while it is pending, but does not impede readers.
7809: **
7810: ** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd>
7811: ** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the
7812: ** addition that it also truncates the log file to zero bytes just prior
7813: ** to a successful return.
7814: ** </dl>
7815: **
7816: ** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in
7817: ** the log file or to -1 if the checkpoint could not run because
7818: ** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not
7819: ** NULL,then *pnCkpt is set to the total number of checkpointed frames in the
7820: ** log file (including any that were already checkpointed before the function
7821: ** was called) or to -1 if the checkpoint could not run due to an error or
7822: ** because the database is not in WAL mode. ^Note that upon successful
7823: ** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been
7824: ** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero.
7825: **
7826: ** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If
7827: ** any other process is running a checkpoint operation at the same time, the
7828: ** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a
7829: ** busy-handler configured, it will not be invoked in this case.
7830: **
7831: ** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the
7832: ** exclusive "writer" lock on the database file. ^If the writer lock cannot be
7833: ** obtained immediately, and a busy-handler is configured, it is invoked and
7834: ** the writer lock retried until either the busy-handler returns 0 or the lock
7835: ** is successfully obtained. ^The busy-handler is also invoked while waiting for
7836: ** database readers as described above. ^If the busy-handler returns 0 before
7837: ** the writer lock is obtained or while waiting for database readers, the
7838: ** checkpoint operation proceeds from that point in the same way as
7839: ** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible
7840: ** without blocking any further. ^SQLITE_BUSY is returned in this case.
7841: **
7842: ** ^If parameter zDb is NULL or points to a zero length string, then the
7843: ** specified operation is attempted on all WAL databases [attached] to
7844: ** [database connection] db. In this case the
7845: ** values written to output parameters *pnLog and *pnCkpt are undefined. ^If
7846: ** an SQLITE_BUSY error is encountered when processing one or more of the
7847: ** attached WAL databases, the operation is still attempted on any remaining
7848: ** attached databases and SQLITE_BUSY is returned at the end. ^If any other
7849: ** error occurs while processing an attached database, processing is abandoned
7850: ** and the error code is returned to the caller immediately. ^If no error
7851: ** (SQLITE_BUSY or otherwise) is encountered while processing the attached
7852: ** databases, SQLITE_OK is returned.
7853: **
7854: ** ^If database zDb is the name of an attached database that is not in WAL
7855: ** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If
7856: ** zDb is not NULL (or a zero length string) and is not the name of any
7857: ** attached database, SQLITE_ERROR is returned to the caller.
7858: **
7859: ** ^Unless it returns SQLITE_MISUSE,
7860: ** the sqlite3_wal_checkpoint_v2() interface
7861: ** sets the error information that is queried by
7862: ** [sqlite3_errcode()] and [sqlite3_errmsg()].
7863: **
7864: ** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface
7865: ** from SQL.
7866: */
7867: SQLITE_API int sqlite3_wal_checkpoint_v2(
7868: sqlite3 *db, /* Database handle */
7869: const char *zDb, /* Name of attached database (or NULL) */
7870: int eMode, /* SQLITE_CHECKPOINT_* value */
7871: int *pnLog, /* OUT: Size of WAL log in frames */
7872: int *pnCkpt /* OUT: Total number of frames checkpointed */
7873: );
7874:
7875: /*
7876: ** CAPI3REF: Checkpoint Mode Values
7877: ** KEYWORDS: {checkpoint mode}
7878: **
7879: ** These constants define all valid values for the "checkpoint mode" passed
7880: ** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface.
7881: ** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the
7882: ** meaning of each of these checkpoint modes.
7883: */
7884: #define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */
7885: #define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */
7886: #define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */
7887: #define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */
7888:
7889: /*
7890: ** CAPI3REF: Virtual Table Interface Configuration
7891: **
7892: ** This function may be called by either the [xConnect] or [xCreate] method
7893: ** of a [virtual table] implementation to configure
7894: ** various facets of the virtual table interface.
7895: **
7896: ** If this interface is invoked outside the context of an xConnect or
7897: ** xCreate virtual table method then the behavior is undefined.
7898: **
7899: ** At present, there is only one option that may be configured using
7900: ** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options
7901: ** may be added in the future.
7902: */
7903: SQLITE_API int sqlite3_vtab_config(sqlite3*, int op, ...);
7904:
7905: /*
7906: ** CAPI3REF: Virtual Table Configuration Options
7907: **
7908: ** These macros define the various options to the
7909: ** [sqlite3_vtab_config()] interface that [virtual table] implementations
7910: ** can use to customize and optimize their behavior.
7911: **
7912: ** <dl>
7913: ** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT
7914: ** <dd>Calls of the form
7915: ** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
7916: ** where X is an integer. If X is zero, then the [virtual table] whose
7917: ** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not
7918: ** support constraints. In this configuration (which is the default) if
7919: ** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire
7920: ** statement is rolled back as if [ON CONFLICT | OR ABORT] had been
7921: ** specified as part of the users SQL statement, regardless of the actual
7922: ** ON CONFLICT mode specified.
7923: **
7924: ** If X is non-zero, then the virtual table implementation guarantees
7925: ** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before
7926: ** any modifications to internal or persistent data structures have been made.
7927: ** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite
7928: ** is able to roll back a statement or database transaction, and abandon
7929: ** or continue processing the current SQL statement as appropriate.
7930: ** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns
7931: ** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode
7932: ** had been ABORT.
7933: **
7934: ** Virtual table implementations that are required to handle OR REPLACE
7935: ** must do so within the [xUpdate] method. If a call to the
7936: ** [sqlite3_vtab_on_conflict()] function indicates that the current ON
7937: ** CONFLICT policy is REPLACE, the virtual table implementation should
7938: ** silently replace the appropriate rows within the xUpdate callback and
7939: ** return SQLITE_OK. Or, if this is not possible, it may return
7940: ** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT
7941: ** constraint handling.
7942: ** </dl>
7943: */
7944: #define SQLITE_VTAB_CONSTRAINT_SUPPORT 1
7945:
7946: /*
7947: ** CAPI3REF: Determine The Virtual Table Conflict Policy
7948: **
7949: ** This function may only be called from within a call to the [xUpdate] method
7950: ** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The
7951: ** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
7952: ** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
7953: ** of the SQL statement that triggered the call to the [xUpdate] method of the
7954: ** [virtual table].
7955: */
7956: SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *);
7957:
7958: /*
7959: ** CAPI3REF: Conflict resolution modes
7960: ** KEYWORDS: {conflict resolution mode}
7961: **
7962: ** These constants are returned by [sqlite3_vtab_on_conflict()] to
7963: ** inform a [virtual table] implementation what the [ON CONFLICT] mode
7964: ** is for the SQL statement being evaluated.
7965: **
7966: ** Note that the [SQLITE_IGNORE] constant is also used as a potential
7967: ** return value from the [sqlite3_set_authorizer()] callback and that
7968: ** [SQLITE_ABORT] is also a [result code].
7969: */
7970: #define SQLITE_ROLLBACK 1
7971: /* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
7972: #define SQLITE_FAIL 3
7973: /* #define SQLITE_ABORT 4 // Also an error code */
7974: #define SQLITE_REPLACE 5
7975:
7976: /*
7977: ** CAPI3REF: Prepared Statement Scan Status Opcodes
7978: ** KEYWORDS: {scanstatus options}
7979: **
7980: ** The following constants can be used for the T parameter to the
7981: ** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a
7982: ** different metric for sqlite3_stmt_scanstatus() to return.
7983: **
7984: ** When the value returned to V is a string, space to hold that string is
7985: ** managed by the prepared statement S and will be automatically freed when
7986: ** S is finalized.
7987: **
7988: ** <dl>
7989: ** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt>
7990: ** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be
7991: ** set to the total number of times that the X-th loop has run.</dd>
7992: **
7993: ** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt>
7994: ** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set
7995: ** to the total number of rows examined by all iterations of the X-th loop.</dd>
7996: **
7997: ** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt>
7998: ** <dd>^The "double" variable pointed to by the T parameter will be set to the
7999: ** query planner's estimate for the average number of rows output from each
8000: ** iteration of the X-th loop. If the query planner's estimates was accurate,
8001: ** then this value will approximate the quotient NVISIT/NLOOP and the
8002: ** product of this value for all prior loops with the same SELECTID will
8003: ** be the NLOOP value for the current loop.
8004: **
8005: ** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt>
8006: ** <dd>^The "const char *" variable pointed to by the T parameter will be set
8007: ** to a zero-terminated UTF-8 string containing the name of the index or table
8008: ** used for the X-th loop.
8009: **
8010: ** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt>
8011: ** <dd>^The "const char *" variable pointed to by the T parameter will be set
8012: ** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN]
8013: ** description for the X-th loop.
8014: **
8015: ** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt>
8016: ** <dd>^The "int" variable pointed to by the T parameter will be set to the
8017: ** "select-id" for the X-th loop. The select-id identifies which query or
8018: ** subquery the loop is part of. The main query has a select-id of zero.
8019: ** The select-id is the same value as is output in the first column
8020: ** of an [EXPLAIN QUERY PLAN] query.
8021: ** </dl>
8022: */
8023: #define SQLITE_SCANSTAT_NLOOP 0
8024: #define SQLITE_SCANSTAT_NVISIT 1
8025: #define SQLITE_SCANSTAT_EST 2
8026: #define SQLITE_SCANSTAT_NAME 3
8027: #define SQLITE_SCANSTAT_EXPLAIN 4
8028: #define SQLITE_SCANSTAT_SELECTID 5
8029:
8030: /*
8031: ** CAPI3REF: Prepared Statement Scan Status
8032: ** METHOD: sqlite3_stmt
8033: **
8034: ** This interface returns information about the predicted and measured
8035: ** performance for pStmt. Advanced applications can use this
8036: ** interface to compare the predicted and the measured performance and
8037: ** issue warnings and/or rerun [ANALYZE] if discrepancies are found.
8038: **
8039: ** Since this interface is expected to be rarely used, it is only
8040: ** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS]
8041: ** compile-time option.
8042: **
8043: ** The "iScanStatusOp" parameter determines which status information to return.
8044: ** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior
8045: ** of this interface is undefined.
8046: ** ^The requested measurement is written into a variable pointed to by
8047: ** the "pOut" parameter.
8048: ** Parameter "idx" identifies the specific loop to retrieve statistics for.
8049: ** Loops are numbered starting from zero. ^If idx is out of range - less than
8050: ** zero or greater than or equal to the total number of loops used to implement
8051: ** the statement - a non-zero value is returned and the variable that pOut
8052: ** points to is unchanged.
8053: **
8054: ** ^Statistics might not be available for all loops in all statements. ^In cases
8055: ** where there exist loops with no available statistics, this function behaves
8056: ** as if the loop did not exist - it returns non-zero and leave the variable
8057: ** that pOut points to unchanged.
8058: **
8059: ** See also: [sqlite3_stmt_scanstatus_reset()]
8060: */
8061: SQLITE_API int sqlite3_stmt_scanstatus(
8062: sqlite3_stmt *pStmt, /* Prepared statement for which info desired */
8063: int idx, /* Index of loop to report on */
8064: int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */
8065: void *pOut /* Result written here */
8066: );
8067:
8068: /*
8069: ** CAPI3REF: Zero Scan-Status Counters
8070: ** METHOD: sqlite3_stmt
8071: **
8072: ** ^Zero all [sqlite3_stmt_scanstatus()] related event counters.
8073: **
8074: ** This API is only available if the library is built with pre-processor
8075: ** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined.
8076: */
8077: SQLITE_API void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*);
8078:
8079: /*
8080: ** CAPI3REF: Flush caches to disk mid-transaction
8081: **
8082: ** ^If a write-transaction is open on [database connection] D when the
8083: ** [sqlite3_db_cacheflush(D)] interface invoked, any dirty
8084: ** pages in the pager-cache that are not currently in use are written out
8085: ** to disk. A dirty page may be in use if a database cursor created by an
8086: ** active SQL statement is reading from it, or if it is page 1 of a database
8087: ** file (page 1 is always "in use"). ^The [sqlite3_db_cacheflush(D)]
8088: ** interface flushes caches for all schemas - "main", "temp", and
8089: ** any [attached] databases.
8090: **
8091: ** ^If this function needs to obtain extra database locks before dirty pages
8092: ** can be flushed to disk, it does so. ^If those locks cannot be obtained
8093: ** immediately and there is a busy-handler callback configured, it is invoked
8094: ** in the usual manner. ^If the required lock still cannot be obtained, then
8095: ** the database is skipped and an attempt made to flush any dirty pages
8096: ** belonging to the next (if any) database. ^If any databases are skipped
8097: ** because locks cannot be obtained, but no other error occurs, this
8098: ** function returns SQLITE_BUSY.
8099: **
8100: ** ^If any other error occurs while flushing dirty pages to disk (for
8101: ** example an IO error or out-of-memory condition), then processing is
8102: ** abandoned and an SQLite [error code] is returned to the caller immediately.
8103: **
8104: ** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK.
8105: **
8106: ** ^This function does not set the database handle error code or message
8107: ** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions.
8108: */
8109: SQLITE_API int sqlite3_db_cacheflush(sqlite3*);
8110:
8111: /*
8112: ** CAPI3REF: The pre-update hook.
8113: **
8114: ** ^These interfaces are only available if SQLite is compiled using the
8115: ** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option.
8116: **
8117: ** ^The [sqlite3_preupdate_hook()] interface registers a callback function
8118: ** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation
8119: ** on a [rowid table].
8120: ** ^At most one preupdate hook may be registered at a time on a single
8121: ** [database connection]; each call to [sqlite3_preupdate_hook()] overrides
8122: ** the previous setting.
8123: ** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()]
8124: ** with a NULL pointer as the second parameter.
8125: ** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as
8126: ** the first parameter to callbacks.
8127: **
8128: ** ^The preupdate hook only fires for changes to [rowid tables]; the preupdate
8129: ** hook is not invoked for changes to [virtual tables] or [WITHOUT ROWID]
8130: ** tables.
8131: **
8132: ** ^The second parameter to the preupdate callback is a pointer to
8133: ** the [database connection] that registered the preupdate hook.
8134: ** ^The third parameter to the preupdate callback is one of the constants
8135: ** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the
8136: ** kind of update operation that is about to occur.
8137: ** ^(The fourth parameter to the preupdate callback is the name of the
8138: ** database within the database connection that is being modified. This
8139: ** will be "main" for the main database or "temp" for TEMP tables or
8140: ** the name given after the AS keyword in the [ATTACH] statement for attached
8141: ** databases.)^
8142: ** ^The fifth parameter to the preupdate callback is the name of the
8143: ** table that is being modified.
8144: ** ^The sixth parameter to the preupdate callback is the initial [rowid] of the
8145: ** row being changes for SQLITE_UPDATE and SQLITE_DELETE changes and is
8146: ** undefined for SQLITE_INSERT changes.
8147: ** ^The seventh parameter to the preupdate callback is the final [rowid] of
8148: ** the row being changed for SQLITE_UPDATE and SQLITE_INSERT changes and is
8149: ** undefined for SQLITE_DELETE changes.
8150: **
8151: ** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()],
8152: ** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces
8153: ** provide additional information about a preupdate event. These routines
8154: ** may only be called from within a preupdate callback. Invoking any of
8155: ** these routines from outside of a preupdate callback or with a
8156: ** [database connection] pointer that is different from the one supplied
8157: ** to the preupdate callback results in undefined and probably undesirable
8158: ** behavior.
8159: **
8160: ** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns
8161: ** in the row that is being inserted, updated, or deleted.
8162: **
8163: ** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to
8164: ** a [protected sqlite3_value] that contains the value of the Nth column of
8165: ** the table row before it is updated. The N parameter must be between 0
8166: ** and one less than the number of columns or the behavior will be
8167: ** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE
8168: ** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the
8169: ** behavior is undefined. The [sqlite3_value] that P points to
8170: ** will be destroyed when the preupdate callback returns.
8171: **
8172: ** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to
8173: ** a [protected sqlite3_value] that contains the value of the Nth column of
8174: ** the table row after it is updated. The N parameter must be between 0
8175: ** and one less than the number of columns or the behavior will be
8176: ** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE
8177: ** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the
8178: ** behavior is undefined. The [sqlite3_value] that P points to
8179: ** will be destroyed when the preupdate callback returns.
8180: **
8181: ** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate
8182: ** callback was invoked as a result of a direct insert, update, or delete
8183: ** operation; or 1 for inserts, updates, or deletes invoked by top-level
8184: ** triggers; or 2 for changes resulting from triggers called by top-level
8185: ** triggers; and so forth.
8186: **
8187: ** See also: [sqlite3_update_hook()]
8188: */
8189: SQLITE_API SQLITE_EXPERIMENTAL void *sqlite3_preupdate_hook(
8190: sqlite3 *db,
8191: void(*xPreUpdate)(
8192: void *pCtx, /* Copy of third arg to preupdate_hook() */
8193: sqlite3 *db, /* Database handle */
8194: int op, /* SQLITE_UPDATE, DELETE or INSERT */
8195: char const *zDb, /* Database name */
8196: char const *zName, /* Table name */
8197: sqlite3_int64 iKey1, /* Rowid of row about to be deleted/updated */
8198: sqlite3_int64 iKey2 /* New rowid value (for a rowid UPDATE) */
8199: ),
8200: void*
8201: );
8202: SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **);
8203: SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_preupdate_count(sqlite3 *);
8204: SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_preupdate_depth(sqlite3 *);
8205: SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **);
8206:
8207: /*
8208: ** CAPI3REF: Low-level system error code
8209: **
8210: ** ^Attempt to return the underlying operating system error code or error
8211: ** number that caused the most recent I/O error or failure to open a file.
8212: ** The return value is OS-dependent. For example, on unix systems, after
8213: ** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be
8214: ** called to get back the underlying "errno" that caused the problem, such
8215: ** as ENOSPC, EAUTH, EISDIR, and so forth.
8216: */
8217: SQLITE_API int sqlite3_system_errno(sqlite3*);
8218:
8219: /*
8220: ** CAPI3REF: Database Snapshot
8221: ** KEYWORDS: {snapshot}
8222: ** EXPERIMENTAL
8223: **
8224: ** An instance of the snapshot object records the state of a [WAL mode]
8225: ** database for some specific point in history.
8226: **
8227: ** In [WAL mode], multiple [database connections] that are open on the
8228: ** same database file can each be reading a different historical version
8229: ** of the database file. When a [database connection] begins a read
8230: ** transaction, that connection sees an unchanging copy of the database
8231: ** as it existed for the point in time when the transaction first started.
8232: ** Subsequent changes to the database from other connections are not seen
8233: ** by the reader until a new read transaction is started.
8234: **
8235: ** The sqlite3_snapshot object records state information about an historical
8236: ** version of the database file so that it is possible to later open a new read
8237: ** transaction that sees that historical version of the database rather than
8238: ** the most recent version.
8239: **
8240: ** The constructor for this object is [sqlite3_snapshot_get()]. The
8241: ** [sqlite3_snapshot_open()] method causes a fresh read transaction to refer
8242: ** to an historical snapshot (if possible). The destructor for
8243: ** sqlite3_snapshot objects is [sqlite3_snapshot_free()].
8244: */
8245: typedef struct sqlite3_snapshot sqlite3_snapshot;
8246:
8247: /*
8248: ** CAPI3REF: Record A Database Snapshot
8249: ** EXPERIMENTAL
8250: **
8251: ** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a
8252: ** new [sqlite3_snapshot] object that records the current state of
8253: ** schema S in database connection D. ^On success, the
8254: ** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly
8255: ** created [sqlite3_snapshot] object into *P and returns SQLITE_OK.
8256: ** ^If schema S of [database connection] D is not a [WAL mode] database
8257: ** that is in a read transaction, then [sqlite3_snapshot_get(D,S,P)]
8258: ** leaves the *P value unchanged and returns an appropriate [error code].
8259: **
8260: ** The [sqlite3_snapshot] object returned from a successful call to
8261: ** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()]
8262: ** to avoid a memory leak.
8263: **
8264: ** The [sqlite3_snapshot_get()] interface is only available when the
8265: ** SQLITE_ENABLE_SNAPSHOT compile-time option is used.
8266: */
8267: SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_get(
8268: sqlite3 *db,
8269: const char *zSchema,
8270: sqlite3_snapshot **ppSnapshot
8271: );
8272:
8273: /*
8274: ** CAPI3REF: Start a read transaction on an historical snapshot
8275: ** EXPERIMENTAL
8276: **
8277: ** ^The [sqlite3_snapshot_open(D,S,P)] interface starts a
8278: ** read transaction for schema S of
8279: ** [database connection] D such that the read transaction
8280: ** refers to historical [snapshot] P, rather than the most
8281: ** recent change to the database.
8282: ** ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK on success
8283: ** or an appropriate [error code] if it fails.
8284: **
8285: ** ^In order to succeed, a call to [sqlite3_snapshot_open(D,S,P)] must be
8286: ** the first operation following the [BEGIN] that takes the schema S
8287: ** out of [autocommit mode].
8288: ** ^In other words, schema S must not currently be in
8289: ** a transaction for [sqlite3_snapshot_open(D,S,P)] to work, but the
8290: ** database connection D must be out of [autocommit mode].
8291: ** ^A [snapshot] will fail to open if it has been overwritten by a
8292: ** [checkpoint].
8293: ** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the
8294: ** database connection D does not know that the database file for
8295: ** schema S is in [WAL mode]. A database connection might not know
8296: ** that the database file is in [WAL mode] if there has been no prior
8297: ** I/O on that database connection, or if the database entered [WAL mode]
8298: ** after the most recent I/O on the database connection.)^
8299: ** (Hint: Run "[PRAGMA application_id]" against a newly opened
8300: ** database connection in order to make it ready to use snapshots.)
8301: **
8302: ** The [sqlite3_snapshot_open()] interface is only available when the
8303: ** SQLITE_ENABLE_SNAPSHOT compile-time option is used.
8304: */
8305: SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_open(
8306: sqlite3 *db,
8307: const char *zSchema,
8308: sqlite3_snapshot *pSnapshot
8309: );
8310:
8311: /*
8312: ** CAPI3REF: Destroy a snapshot
8313: ** EXPERIMENTAL
8314: **
8315: ** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P.
8316: ** The application must eventually free every [sqlite3_snapshot] object
8317: ** using this routine to avoid a memory leak.
8318: **
8319: ** The [sqlite3_snapshot_free()] interface is only available when the
8320: ** SQLITE_ENABLE_SNAPSHOT compile-time option is used.
8321: */
8322: SQLITE_API SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*);
8323:
8324: /*
8325: ** CAPI3REF: Compare the ages of two snapshot handles.
8326: ** EXPERIMENTAL
8327: **
8328: ** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages
8329: ** of two valid snapshot handles.
8330: **
8331: ** If the two snapshot handles are not associated with the same database
8332: ** file, the result of the comparison is undefined.
8333: **
8334: ** Additionally, the result of the comparison is only valid if both of the
8335: ** snapshot handles were obtained by calling sqlite3_snapshot_get() since the
8336: ** last time the wal file was deleted. The wal file is deleted when the
8337: ** database is changed back to rollback mode or when the number of database
8338: ** clients drops to zero. If either snapshot handle was obtained before the
8339: ** wal file was last deleted, the value returned by this function
8340: ** is undefined.
8341: **
8342: ** Otherwise, this API returns a negative value if P1 refers to an older
8343: ** snapshot than P2, zero if the two handles refer to the same database
8344: ** snapshot, and a positive value if P1 is a newer snapshot than P2.
8345: */
8346: SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp(
8347: sqlite3_snapshot *p1,
8348: sqlite3_snapshot *p2
8349: );
8350:
8351: /*
8352: ** Undo the hack that converts floating point types to integer for
8353: ** builds on processors without floating point support.
8354: */
8355: #ifdef SQLITE_OMIT_FLOATING_POINT
8356: # undef double
8357: #endif
8358:
8359: #ifdef __cplusplus
8360: } /* End of the 'extern "C"' block */
8361: #endif
8362: #endif /* SQLITE3_H */
8363:
8364: /******** Begin file sqlite3rtree.h *********/
8365: /*
8366: ** 2010 August 30
8367: **
8368: ** The author disclaims copyright to this source code. In place of
8369: ** a legal notice, here is a blessing:
8370: **
8371: ** May you do good and not evil.
8372: ** May you find forgiveness for yourself and forgive others.
8373: ** May you share freely, never taking more than you give.
8374: **
8375: *************************************************************************
8376: */
8377:
8378: #ifndef _SQLITE3RTREE_H_
8379: #define _SQLITE3RTREE_H_
8380:
8381:
8382: #ifdef __cplusplus
8383: extern "C" {
8384: #endif
8385:
8386: typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry;
8387: typedef struct sqlite3_rtree_query_info sqlite3_rtree_query_info;
8388:
8389: /* The double-precision datatype used by RTree depends on the
8390: ** SQLITE_RTREE_INT_ONLY compile-time option.
8391: */
8392: #ifdef SQLITE_RTREE_INT_ONLY
8393: typedef sqlite3_int64 sqlite3_rtree_dbl;
8394: #else
8395: typedef double sqlite3_rtree_dbl;
8396: #endif
8397:
8398: /*
8399: ** Register a geometry callback named zGeom that can be used as part of an
8400: ** R-Tree geometry query as follows:
8401: **
8402: ** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...)
8403: */
8404: SQLITE_API int sqlite3_rtree_geometry_callback(
8405: sqlite3 *db,
8406: const char *zGeom,
8407: int (*xGeom)(sqlite3_rtree_geometry*, int, sqlite3_rtree_dbl*,int*),
8408: void *pContext
8409: );
8410:
8411:
8412: /*
8413: ** A pointer to a structure of the following type is passed as the first
8414: ** argument to callbacks registered using rtree_geometry_callback().
8415: */
8416: struct sqlite3_rtree_geometry {
8417: void *pContext; /* Copy of pContext passed to s_r_g_c() */
8418: int nParam; /* Size of array aParam[] */
8419: sqlite3_rtree_dbl *aParam; /* Parameters passed to SQL geom function */
8420: void *pUser; /* Callback implementation user data */
8421: void (*xDelUser)(void *); /* Called by SQLite to clean up pUser */
8422: };
8423:
8424: /*
8425: ** Register a 2nd-generation geometry callback named zScore that can be
8426: ** used as part of an R-Tree geometry query as follows:
8427: **
8428: ** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zQueryFunc(... params ...)
8429: */
8430: SQLITE_API int sqlite3_rtree_query_callback(
8431: sqlite3 *db,
8432: const char *zQueryFunc,
8433: int (*xQueryFunc)(sqlite3_rtree_query_info*),
8434: void *pContext,
8435: void (*xDestructor)(void*)
8436: );
8437:
8438:
8439: /*
8440: ** A pointer to a structure of the following type is passed as the
8441: ** argument to scored geometry callback registered using
8442: ** sqlite3_rtree_query_callback().
8443: **
8444: ** Note that the first 5 fields of this structure are identical to
8445: ** sqlite3_rtree_geometry. This structure is a subclass of
8446: ** sqlite3_rtree_geometry.
8447: */
8448: struct sqlite3_rtree_query_info {
8449: void *pContext; /* pContext from when function registered */
8450: int nParam; /* Number of function parameters */
8451: sqlite3_rtree_dbl *aParam; /* value of function parameters */
8452: void *pUser; /* callback can use this, if desired */
8453: void (*xDelUser)(void*); /* function to free pUser */
8454: sqlite3_rtree_dbl *aCoord; /* Coordinates of node or entry to check */
8455: unsigned int *anQueue; /* Number of pending entries in the queue */
8456: int nCoord; /* Number of coordinates */
8457: int iLevel; /* Level of current node or entry */
8458: int mxLevel; /* The largest iLevel value in the tree */
8459: sqlite3_int64 iRowid; /* Rowid for current entry */
8460: sqlite3_rtree_dbl rParentScore; /* Score of parent node */
8461: int eParentWithin; /* Visibility of parent node */
8462: int eWithin; /* OUT: Visiblity */
8463: sqlite3_rtree_dbl rScore; /* OUT: Write the score here */
8464: /* The following fields are only available in 3.8.11 and later */
8465: sqlite3_value **apSqlParam; /* Original SQL values of parameters */
8466: };
8467:
8468: /*
8469: ** Allowed values for sqlite3_rtree_query.eWithin and .eParentWithin.
8470: */
8471: #define NOT_WITHIN 0 /* Object completely outside of query region */
8472: #define PARTLY_WITHIN 1 /* Object partially overlaps query region */
8473: #define FULLY_WITHIN 2 /* Object fully contained within query region */
8474:
8475:
8476: #ifdef __cplusplus
8477: } /* end of the 'extern "C"' block */
8478: #endif
8479:
8480: #endif /* ifndef _SQLITE3RTREE_H_ */
8481:
8482: /******** End of sqlite3rtree.h *********/
8483: /******** Begin file sqlite3session.h *********/
8484:
8485: #if !defined(__SQLITESESSION_H_) && defined(SQLITE_ENABLE_SESSION)
8486: #define __SQLITESESSION_H_ 1
8487:
8488: /*
8489: ** Make sure we can call this stuff from C++.
8490: */
8491: #ifdef __cplusplus
8492: extern "C" {
8493: #endif
8494:
8495:
8496: /*
8497: ** CAPI3REF: Session Object Handle
8498: */
8499: typedef struct sqlite3_session sqlite3_session;
8500:
8501: /*
8502: ** CAPI3REF: Changeset Iterator Handle
8503: */
8504: typedef struct sqlite3_changeset_iter sqlite3_changeset_iter;
8505:
8506: /*
8507: ** CAPI3REF: Create A New Session Object
8508: **
8509: ** Create a new session object attached to database handle db. If successful,
8510: ** a pointer to the new object is written to *ppSession and SQLITE_OK is
8511: ** returned. If an error occurs, *ppSession is set to NULL and an SQLite
8512: ** error code (e.g. SQLITE_NOMEM) is returned.
8513: **
8514: ** It is possible to create multiple session objects attached to a single
8515: ** database handle.
8516: **
8517: ** Session objects created using this function should be deleted using the
8518: ** [sqlite3session_delete()] function before the database handle that they
8519: ** are attached to is itself closed. If the database handle is closed before
8520: ** the session object is deleted, then the results of calling any session
8521: ** module function, including [sqlite3session_delete()] on the session object
8522: ** are undefined.
8523: **
8524: ** Because the session module uses the [sqlite3_preupdate_hook()] API, it
8525: ** is not possible for an application to register a pre-update hook on a
8526: ** database handle that has one or more session objects attached. Nor is
8527: ** it possible to create a session object attached to a database handle for
8528: ** which a pre-update hook is already defined. The results of attempting
8529: ** either of these things are undefined.
8530: **
8531: ** The session object will be used to create changesets for tables in
8532: ** database zDb, where zDb is either "main", or "temp", or the name of an
8533: ** attached database. It is not an error if database zDb is not attached
8534: ** to the database when the session object is created.
8535: */
8536: int sqlite3session_create(
8537: sqlite3 *db, /* Database handle */
8538: const char *zDb, /* Name of db (e.g. "main") */
8539: sqlite3_session **ppSession /* OUT: New session object */
8540: );
8541:
8542: /*
8543: ** CAPI3REF: Delete A Session Object
8544: **
8545: ** Delete a session object previously allocated using
8546: ** [sqlite3session_create()]. Once a session object has been deleted, the
8547: ** results of attempting to use pSession with any other session module
8548: ** function are undefined.
8549: **
8550: ** Session objects must be deleted before the database handle to which they
8551: ** are attached is closed. Refer to the documentation for
8552: ** [sqlite3session_create()] for details.
8553: */
8554: void sqlite3session_delete(sqlite3_session *pSession);
8555:
8556:
8557: /*
8558: ** CAPI3REF: Enable Or Disable A Session Object
8559: **
8560: ** Enable or disable the recording of changes by a session object. When
8561: ** enabled, a session object records changes made to the database. When
8562: ** disabled - it does not. A newly created session object is enabled.
8563: ** Refer to the documentation for [sqlite3session_changeset()] for further
8564: ** details regarding how enabling and disabling a session object affects
8565: ** the eventual changesets.
8566: **
8567: ** Passing zero to this function disables the session. Passing a value
8568: ** greater than zero enables it. Passing a value less than zero is a
8569: ** no-op, and may be used to query the current state of the session.
8570: **
8571: ** The return value indicates the final state of the session object: 0 if
8572: ** the session is disabled, or 1 if it is enabled.
8573: */
8574: int sqlite3session_enable(sqlite3_session *pSession, int bEnable);
8575:
8576: /*
8577: ** CAPI3REF: Set Or Clear the Indirect Change Flag
8578: **
8579: ** Each change recorded by a session object is marked as either direct or
8580: ** indirect. A change is marked as indirect if either:
8581: **
8582: ** <ul>
8583: ** <li> The session object "indirect" flag is set when the change is
8584: ** made, or
8585: ** <li> The change is made by an SQL trigger or foreign key action
8586: ** instead of directly as a result of a users SQL statement.
8587: ** </ul>
8588: **
8589: ** If a single row is affected by more than one operation within a session,
8590: ** then the change is considered indirect if all operations meet the criteria
8591: ** for an indirect change above, or direct otherwise.
8592: **
8593: ** This function is used to set, clear or query the session object indirect
8594: ** flag. If the second argument passed to this function is zero, then the
8595: ** indirect flag is cleared. If it is greater than zero, the indirect flag
8596: ** is set. Passing a value less than zero does not modify the current value
8597: ** of the indirect flag, and may be used to query the current state of the
8598: ** indirect flag for the specified session object.
8599: **
8600: ** The return value indicates the final state of the indirect flag: 0 if
8601: ** it is clear, or 1 if it is set.
8602: */
8603: int sqlite3session_indirect(sqlite3_session *pSession, int bIndirect);
8604:
8605: /*
8606: ** CAPI3REF: Attach A Table To A Session Object
8607: **
8608: ** If argument zTab is not NULL, then it is the name of a table to attach
8609: ** to the session object passed as the first argument. All subsequent changes
8610: ** made to the table while the session object is enabled will be recorded. See
8611: ** documentation for [sqlite3session_changeset()] for further details.
8612: **
8613: ** Or, if argument zTab is NULL, then changes are recorded for all tables
8614: ** in the database. If additional tables are added to the database (by
8615: ** executing "CREATE TABLE" statements) after this call is made, changes for
8616: ** the new tables are also recorded.
8617: **
8618: ** Changes can only be recorded for tables that have a PRIMARY KEY explicitly
8619: ** defined as part of their CREATE TABLE statement. It does not matter if the
8620: ** PRIMARY KEY is an "INTEGER PRIMARY KEY" (rowid alias) or not. The PRIMARY
8621: ** KEY may consist of a single column, or may be a composite key.
8622: **
8623: ** It is not an error if the named table does not exist in the database. Nor
8624: ** is it an error if the named table does not have a PRIMARY KEY. However,
8625: ** no changes will be recorded in either of these scenarios.
8626: **
8627: ** Changes are not recorded for individual rows that have NULL values stored
8628: ** in one or more of their PRIMARY KEY columns.
8629: **
8630: ** SQLITE_OK is returned if the call completes without error. Or, if an error
8631: ** occurs, an SQLite error code (e.g. SQLITE_NOMEM) is returned.
8632: */
8633: int sqlite3session_attach(
8634: sqlite3_session *pSession, /* Session object */
8635: const char *zTab /* Table name */
8636: );
8637:
8638: /*
8639: ** CAPI3REF: Set a table filter on a Session Object.
8640: **
8641: ** The second argument (xFilter) is the "filter callback". For changes to rows
8642: ** in tables that are not attached to the Session oject, the filter is called
8643: ** to determine whether changes to the table's rows should be tracked or not.
8644: ** If xFilter returns 0, changes is not tracked. Note that once a table is
8645: ** attached, xFilter will not be called again.
8646: */
8647: void sqlite3session_table_filter(
8648: sqlite3_session *pSession, /* Session object */
8649: int(*xFilter)(
8650: void *pCtx, /* Copy of third arg to _filter_table() */
8651: const char *zTab /* Table name */
8652: ),
8653: void *pCtx /* First argument passed to xFilter */
8654: );
8655:
8656: /*
8657: ** CAPI3REF: Generate A Changeset From A Session Object
8658: **
8659: ** Obtain a changeset containing changes to the tables attached to the
8660: ** session object passed as the first argument. If successful,
8661: ** set *ppChangeset to point to a buffer containing the changeset
8662: ** and *pnChangeset to the size of the changeset in bytes before returning
8663: ** SQLITE_OK. If an error occurs, set both *ppChangeset and *pnChangeset to
8664: ** zero and return an SQLite error code.
8665: **
8666: ** A changeset consists of zero or more INSERT, UPDATE and/or DELETE changes,
8667: ** each representing a change to a single row of an attached table. An INSERT
8668: ** change contains the values of each field of a new database row. A DELETE
8669: ** contains the original values of each field of a deleted database row. An
8670: ** UPDATE change contains the original values of each field of an updated
8671: ** database row along with the updated values for each updated non-primary-key
8672: ** column. It is not possible for an UPDATE change to represent a change that
8673: ** modifies the values of primary key columns. If such a change is made, it
8674: ** is represented in a changeset as a DELETE followed by an INSERT.
8675: **
8676: ** Changes are not recorded for rows that have NULL values stored in one or
8677: ** more of their PRIMARY KEY columns. If such a row is inserted or deleted,
8678: ** no corresponding change is present in the changesets returned by this
8679: ** function. If an existing row with one or more NULL values stored in
8680: ** PRIMARY KEY columns is updated so that all PRIMARY KEY columns are non-NULL,
8681: ** only an INSERT is appears in the changeset. Similarly, if an existing row
8682: ** with non-NULL PRIMARY KEY values is updated so that one or more of its
8683: ** PRIMARY KEY columns are set to NULL, the resulting changeset contains a
8684: ** DELETE change only.
8685: **
8686: ** The contents of a changeset may be traversed using an iterator created
8687: ** using the [sqlite3changeset_start()] API. A changeset may be applied to
8688: ** a database with a compatible schema using the [sqlite3changeset_apply()]
8689: ** API.
8690: **
8691: ** Within a changeset generated by this function, all changes related to a
8692: ** single table are grouped together. In other words, when iterating through
8693: ** a changeset or when applying a changeset to a database, all changes related
8694: ** to a single table are processed before moving on to the next table. Tables
8695: ** are sorted in the same order in which they were attached (or auto-attached)
8696: ** to the sqlite3_session object. The order in which the changes related to
8697: ** a single table are stored is undefined.
8698: **
8699: ** Following a successful call to this function, it is the responsibility of
8700: ** the caller to eventually free the buffer that *ppChangeset points to using
8701: ** [sqlite3_free()].
8702: **
8703: ** <h3>Changeset Generation</h3>
8704: **
8705: ** Once a table has been attached to a session object, the session object
8706: ** records the primary key values of all new rows inserted into the table.
8707: ** It also records the original primary key and other column values of any
8708: ** deleted or updated rows. For each unique primary key value, data is only
8709: ** recorded once - the first time a row with said primary key is inserted,
8710: ** updated or deleted in the lifetime of the session.
8711: **
8712: ** There is one exception to the previous paragraph: when a row is inserted,
8713: ** updated or deleted, if one or more of its primary key columns contain a
8714: ** NULL value, no record of the change is made.
8715: **
8716: ** The session object therefore accumulates two types of records - those
8717: ** that consist of primary key values only (created when the user inserts
8718: ** a new record) and those that consist of the primary key values and the
8719: ** original values of other table columns (created when the users deletes
8720: ** or updates a record).
8721: **
8722: ** When this function is called, the requested changeset is created using
8723: ** both the accumulated records and the current contents of the database
8724: ** file. Specifically:
8725: **
8726: ** <ul>
8727: ** <li> For each record generated by an insert, the database is queried
8728: ** for a row with a matching primary key. If one is found, an INSERT
8729: ** change is added to the changeset. If no such row is found, no change
8730: ** is added to the changeset.
8731: **
8732: ** <li> For each record generated by an update or delete, the database is
8733: ** queried for a row with a matching primary key. If such a row is
8734: ** found and one or more of the non-primary key fields have been
8735: ** modified from their original values, an UPDATE change is added to
8736: ** the changeset. Or, if no such row is found in the table, a DELETE
8737: ** change is added to the changeset. If there is a row with a matching
8738: ** primary key in the database, but all fields contain their original
8739: ** values, no change is added to the changeset.
8740: ** </ul>
8741: **
8742: ** This means, amongst other things, that if a row is inserted and then later
8743: ** deleted while a session object is active, neither the insert nor the delete
8744: ** will be present in the changeset. Or if a row is deleted and then later a
8745: ** row with the same primary key values inserted while a session object is
8746: ** active, the resulting changeset will contain an UPDATE change instead of
8747: ** a DELETE and an INSERT.
8748: **
8749: ** When a session object is disabled (see the [sqlite3session_enable()] API),
8750: ** it does not accumulate records when rows are inserted, updated or deleted.
8751: ** This may appear to have some counter-intuitive effects if a single row
8752: ** is written to more than once during a session. For example, if a row
8753: ** is inserted while a session object is enabled, then later deleted while
8754: ** the same session object is disabled, no INSERT record will appear in the
8755: ** changeset, even though the delete took place while the session was disabled.
8756: ** Or, if one field of a row is updated while a session is disabled, and
8757: ** another field of the same row is updated while the session is enabled, the
8758: ** resulting changeset will contain an UPDATE change that updates both fields.
8759: */
8760: int sqlite3session_changeset(
8761: sqlite3_session *pSession, /* Session object */
8762: int *pnChangeset, /* OUT: Size of buffer at *ppChangeset */
8763: void **ppChangeset /* OUT: Buffer containing changeset */
8764: );
8765:
8766: /*
8767: ** CAPI3REF: Load The Difference Between Tables Into A Session
8768: **
8769: ** If it is not already attached to the session object passed as the first
8770: ** argument, this function attaches table zTbl in the same manner as the
8771: ** [sqlite3session_attach()] function. If zTbl does not exist, or if it
8772: ** does not have a primary key, this function is a no-op (but does not return
8773: ** an error).
8774: **
8775: ** Argument zFromDb must be the name of a database ("main", "temp" etc.)
8776: ** attached to the same database handle as the session object that contains
8777: ** a table compatible with the table attached to the session by this function.
8778: ** A table is considered compatible if it:
8779: **
8780: ** <ul>
8781: ** <li> Has the same name,
8782: ** <li> Has the same set of columns declared in the same order, and
8783: ** <li> Has the same PRIMARY KEY definition.
8784: ** </ul>
8785: **
8786: ** If the tables are not compatible, SQLITE_SCHEMA is returned. If the tables
8787: ** are compatible but do not have any PRIMARY KEY columns, it is not an error
8788: ** but no changes are added to the session object. As with other session
8789: ** APIs, tables without PRIMARY KEYs are simply ignored.
8790: **
8791: ** This function adds a set of changes to the session object that could be
8792: ** used to update the table in database zFrom (call this the "from-table")
8793: ** so that its content is the same as the table attached to the session
8794: ** object (call this the "to-table"). Specifically:
8795: **
8796: ** <ul>
8797: ** <li> For each row (primary key) that exists in the to-table but not in
8798: ** the from-table, an INSERT record is added to the session object.
8799: **
8800: ** <li> For each row (primary key) that exists in the to-table but not in
8801: ** the from-table, a DELETE record is added to the session object.
8802: **
8803: ** <li> For each row (primary key) that exists in both tables, but features
8804: ** different in each, an UPDATE record is added to the session.
8805: ** </ul>
8806: **
8807: ** To clarify, if this function is called and then a changeset constructed
8808: ** using [sqlite3session_changeset()], then after applying that changeset to
8809: ** database zFrom the contents of the two compatible tables would be
8810: ** identical.
8811: **
8812: ** It an error if database zFrom does not exist or does not contain the
8813: ** required compatible table.
8814: **
8815: ** If the operation successful, SQLITE_OK is returned. Otherwise, an SQLite
8816: ** error code. In this case, if argument pzErrMsg is not NULL, *pzErrMsg
8817: ** may be set to point to a buffer containing an English language error
8818: ** message. It is the responsibility of the caller to free this buffer using
8819: ** sqlite3_free().
8820: */
8821: int sqlite3session_diff(
8822: sqlite3_session *pSession,
8823: const char *zFromDb,
8824: const char *zTbl,
8825: char **pzErrMsg
8826: );
8827:
8828:
8829: /*
8830: ** CAPI3REF: Generate A Patchset From A Session Object
8831: **
8832: ** The differences between a patchset and a changeset are that:
8833: **
8834: ** <ul>
8835: ** <li> DELETE records consist of the primary key fields only. The
8836: ** original values of other fields are omitted.
8837: ** <li> The original values of any modified fields are omitted from
8838: ** UPDATE records.
8839: ** </ul>
8840: **
8841: ** A patchset blob may be used with up to date versions of all
8842: ** sqlite3changeset_xxx API functions except for sqlite3changeset_invert(),
8843: ** which returns SQLITE_CORRUPT if it is passed a patchset. Similarly,
8844: ** attempting to use a patchset blob with old versions of the
8845: ** sqlite3changeset_xxx APIs also provokes an SQLITE_CORRUPT error.
8846: **
8847: ** Because the non-primary key "old.*" fields are omitted, no
8848: ** SQLITE_CHANGESET_DATA conflicts can be detected or reported if a patchset
8849: ** is passed to the sqlite3changeset_apply() API. Other conflict types work
8850: ** in the same way as for changesets.
8851: **
8852: ** Changes within a patchset are ordered in the same way as for changesets
8853: ** generated by the sqlite3session_changeset() function (i.e. all changes for
8854: ** a single table are grouped together, tables appear in the order in which
8855: ** they were attached to the session object).
8856: */
8857: int sqlite3session_patchset(
8858: sqlite3_session *pSession, /* Session object */
8859: int *pnPatchset, /* OUT: Size of buffer at *ppChangeset */
8860: void **ppPatchset /* OUT: Buffer containing changeset */
8861: );
8862:
8863: /*
8864: ** CAPI3REF: Test if a changeset has recorded any changes.
8865: **
8866: ** Return non-zero if no changes to attached tables have been recorded by
8867: ** the session object passed as the first argument. Otherwise, if one or
8868: ** more changes have been recorded, return zero.
8869: **
8870: ** Even if this function returns zero, it is possible that calling
8871: ** [sqlite3session_changeset()] on the session handle may still return a
8872: ** changeset that contains no changes. This can happen when a row in
8873: ** an attached table is modified and then later on the original values
8874: ** are restored. However, if this function returns non-zero, then it is
8875: ** guaranteed that a call to sqlite3session_changeset() will return a
8876: ** changeset containing zero changes.
8877: */
8878: int sqlite3session_isempty(sqlite3_session *pSession);
8879:
8880: /*
8881: ** CAPI3REF: Create An Iterator To Traverse A Changeset
8882: **
8883: ** Create an iterator used to iterate through the contents of a changeset.
8884: ** If successful, *pp is set to point to the iterator handle and SQLITE_OK
8885: ** is returned. Otherwise, if an error occurs, *pp is set to zero and an
8886: ** SQLite error code is returned.
8887: **
8888: ** The following functions can be used to advance and query a changeset
8889: ** iterator created by this function:
8890: **
8891: ** <ul>
8892: ** <li> [sqlite3changeset_next()]
8893: ** <li> [sqlite3changeset_op()]
8894: ** <li> [sqlite3changeset_new()]
8895: ** <li> [sqlite3changeset_old()]
8896: ** </ul>
8897: **
8898: ** It is the responsibility of the caller to eventually destroy the iterator
8899: ** by passing it to [sqlite3changeset_finalize()]. The buffer containing the
8900: ** changeset (pChangeset) must remain valid until after the iterator is
8901: ** destroyed.
8902: **
8903: ** Assuming the changeset blob was created by one of the
8904: ** [sqlite3session_changeset()], [sqlite3changeset_concat()] or
8905: ** [sqlite3changeset_invert()] functions, all changes within the changeset
8906: ** that apply to a single table are grouped together. This means that when
8907: ** an application iterates through a changeset using an iterator created by
8908: ** this function, all changes that relate to a single table are visted
8909: ** consecutively. There is no chance that the iterator will visit a change
8910: ** the applies to table X, then one for table Y, and then later on visit
8911: ** another change for table X.
8912: */
8913: int sqlite3changeset_start(
8914: sqlite3_changeset_iter **pp, /* OUT: New changeset iterator handle */
8915: int nChangeset, /* Size of changeset blob in bytes */
8916: void *pChangeset /* Pointer to blob containing changeset */
8917: );
8918:
8919:
8920: /*
8921: ** CAPI3REF: Advance A Changeset Iterator
8922: **
8923: ** This function may only be used with iterators created by function
8924: ** [sqlite3changeset_start()]. If it is called on an iterator passed to
8925: ** a conflict-handler callback by [sqlite3changeset_apply()], SQLITE_MISUSE
8926: ** is returned and the call has no effect.
8927: **
8928: ** Immediately after an iterator is created by sqlite3changeset_start(), it
8929: ** does not point to any change in the changeset. Assuming the changeset
8930: ** is not empty, the first call to this function advances the iterator to
8931: ** point to the first change in the changeset. Each subsequent call advances
8932: ** the iterator to point to the next change in the changeset (if any). If
8933: ** no error occurs and the iterator points to a valid change after a call
8934: ** to sqlite3changeset_next() has advanced it, SQLITE_ROW is returned.
8935: ** Otherwise, if all changes in the changeset have already been visited,
8936: ** SQLITE_DONE is returned.
8937: **
8938: ** If an error occurs, an SQLite error code is returned. Possible error
8939: ** codes include SQLITE_CORRUPT (if the changeset buffer is corrupt) or
8940: ** SQLITE_NOMEM.
8941: */
8942: int sqlite3changeset_next(sqlite3_changeset_iter *pIter);
8943:
8944: /*
8945: ** CAPI3REF: Obtain The Current Operation From A Changeset Iterator
8946: **
8947: ** The pIter argument passed to this function may either be an iterator
8948: ** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
8949: ** created by [sqlite3changeset_start()]. In the latter case, the most recent
8950: ** call to [sqlite3changeset_next()] must have returned [SQLITE_ROW]. If this
8951: ** is not the case, this function returns [SQLITE_MISUSE].
8952: **
8953: ** If argument pzTab is not NULL, then *pzTab is set to point to a
8954: ** nul-terminated utf-8 encoded string containing the name of the table
8955: ** affected by the current change. The buffer remains valid until either
8956: ** sqlite3changeset_next() is called on the iterator or until the
8957: ** conflict-handler function returns. If pnCol is not NULL, then *pnCol is
8958: ** set to the number of columns in the table affected by the change. If
8959: ** pbIncorrect is not NULL, then *pbIndirect is set to true (1) if the change
8960: ** is an indirect change, or false (0) otherwise. See the documentation for
8961: ** [sqlite3session_indirect()] for a description of direct and indirect
8962: ** changes. Finally, if pOp is not NULL, then *pOp is set to one of
8963: ** [SQLITE_INSERT], [SQLITE_DELETE] or [SQLITE_UPDATE], depending on the
8964: ** type of change that the iterator currently points to.
8965: **
8966: ** If no error occurs, SQLITE_OK is returned. If an error does occur, an
8967: ** SQLite error code is returned. The values of the output variables may not
8968: ** be trusted in this case.
8969: */
8970: int sqlite3changeset_op(
8971: sqlite3_changeset_iter *pIter, /* Iterator object */
8972: const char **pzTab, /* OUT: Pointer to table name */
8973: int *pnCol, /* OUT: Number of columns in table */
8974: int *pOp, /* OUT: SQLITE_INSERT, DELETE or UPDATE */
8975: int *pbIndirect /* OUT: True for an 'indirect' change */
8976: );
8977:
8978: /*
8979: ** CAPI3REF: Obtain The Primary Key Definition Of A Table
8980: **
8981: ** For each modified table, a changeset includes the following:
8982: **
8983: ** <ul>
8984: ** <li> The number of columns in the table, and
8985: ** <li> Which of those columns make up the tables PRIMARY KEY.
8986: ** </ul>
8987: **
8988: ** This function is used to find which columns comprise the PRIMARY KEY of
8989: ** the table modified by the change that iterator pIter currently points to.
8990: ** If successful, *pabPK is set to point to an array of nCol entries, where
8991: ** nCol is the number of columns in the table. Elements of *pabPK are set to
8992: ** 0x01 if the corresponding column is part of the tables primary key, or
8993: ** 0x00 if it is not.
8994: **
8995: ** If argumet pnCol is not NULL, then *pnCol is set to the number of columns
8996: ** in the table.
8997: **
8998: ** If this function is called when the iterator does not point to a valid
8999: ** entry, SQLITE_MISUSE is returned and the output variables zeroed. Otherwise,
9000: ** SQLITE_OK is returned and the output variables populated as described
9001: ** above.
9002: */
9003: int sqlite3changeset_pk(
9004: sqlite3_changeset_iter *pIter, /* Iterator object */
9005: unsigned char **pabPK, /* OUT: Array of boolean - true for PK cols */
9006: int *pnCol /* OUT: Number of entries in output array */
9007: );
9008:
9009: /*
9010: ** CAPI3REF: Obtain old.* Values From A Changeset Iterator
9011: **
9012: ** The pIter argument passed to this function may either be an iterator
9013: ** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
9014: ** created by [sqlite3changeset_start()]. In the latter case, the most recent
9015: ** call to [sqlite3changeset_next()] must have returned SQLITE_ROW.
9016: ** Furthermore, it may only be called if the type of change that the iterator
9017: ** currently points to is either [SQLITE_DELETE] or [SQLITE_UPDATE]. Otherwise,
9018: ** this function returns [SQLITE_MISUSE] and sets *ppValue to NULL.
9019: **
9020: ** Argument iVal must be greater than or equal to 0, and less than the number
9021: ** of columns in the table affected by the current change. Otherwise,
9022: ** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
9023: **
9024: ** If successful, this function sets *ppValue to point to a protected
9025: ** sqlite3_value object containing the iVal'th value from the vector of
9026: ** original row values stored as part of the UPDATE or DELETE change and
9027: ** returns SQLITE_OK. The name of the function comes from the fact that this
9028: ** is similar to the "old.*" columns available to update or delete triggers.
9029: **
9030: ** If some other error occurs (e.g. an OOM condition), an SQLite error code
9031: ** is returned and *ppValue is set to NULL.
9032: */
9033: int sqlite3changeset_old(
9034: sqlite3_changeset_iter *pIter, /* Changeset iterator */
9035: int iVal, /* Column number */
9036: sqlite3_value **ppValue /* OUT: Old value (or NULL pointer) */
9037: );
9038:
9039: /*
9040: ** CAPI3REF: Obtain new.* Values From A Changeset Iterator
9041: **
9042: ** The pIter argument passed to this function may either be an iterator
9043: ** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
9044: ** created by [sqlite3changeset_start()]. In the latter case, the most recent
9045: ** call to [sqlite3changeset_next()] must have returned SQLITE_ROW.
9046: ** Furthermore, it may only be called if the type of change that the iterator
9047: ** currently points to is either [SQLITE_UPDATE] or [SQLITE_INSERT]. Otherwise,
9048: ** this function returns [SQLITE_MISUSE] and sets *ppValue to NULL.
9049: **
9050: ** Argument iVal must be greater than or equal to 0, and less than the number
9051: ** of columns in the table affected by the current change. Otherwise,
9052: ** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
9053: **
9054: ** If successful, this function sets *ppValue to point to a protected
9055: ** sqlite3_value object containing the iVal'th value from the vector of
9056: ** new row values stored as part of the UPDATE or INSERT change and
9057: ** returns SQLITE_OK. If the change is an UPDATE and does not include
9058: ** a new value for the requested column, *ppValue is set to NULL and
9059: ** SQLITE_OK returned. The name of the function comes from the fact that
9060: ** this is similar to the "new.*" columns available to update or delete
9061: ** triggers.
9062: **
9063: ** If some other error occurs (e.g. an OOM condition), an SQLite error code
9064: ** is returned and *ppValue is set to NULL.
9065: */
9066: int sqlite3changeset_new(
9067: sqlite3_changeset_iter *pIter, /* Changeset iterator */
9068: int iVal, /* Column number */
9069: sqlite3_value **ppValue /* OUT: New value (or NULL pointer) */
9070: );
9071:
9072: /*
9073: ** CAPI3REF: Obtain Conflicting Row Values From A Changeset Iterator
9074: **
9075: ** This function should only be used with iterator objects passed to a
9076: ** conflict-handler callback by [sqlite3changeset_apply()] with either
9077: ** [SQLITE_CHANGESET_DATA] or [SQLITE_CHANGESET_CONFLICT]. If this function
9078: ** is called on any other iterator, [SQLITE_MISUSE] is returned and *ppValue
9079: ** is set to NULL.
9080: **
9081: ** Argument iVal must be greater than or equal to 0, and less than the number
9082: ** of columns in the table affected by the current change. Otherwise,
9083: ** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
9084: **
9085: ** If successful, this function sets *ppValue to point to a protected
9086: ** sqlite3_value object containing the iVal'th value from the
9087: ** "conflicting row" associated with the current conflict-handler callback
9088: ** and returns SQLITE_OK.
9089: **
9090: ** If some other error occurs (e.g. an OOM condition), an SQLite error code
9091: ** is returned and *ppValue is set to NULL.
9092: */
9093: int sqlite3changeset_conflict(
9094: sqlite3_changeset_iter *pIter, /* Changeset iterator */
9095: int iVal, /* Column number */
9096: sqlite3_value **ppValue /* OUT: Value from conflicting row */
9097: );
9098:
9099: /*
9100: ** CAPI3REF: Determine The Number Of Foreign Key Constraint Violations
9101: **
9102: ** This function may only be called with an iterator passed to an
9103: ** SQLITE_CHANGESET_FOREIGN_KEY conflict handler callback. In this case
9104: ** it sets the output variable to the total number of known foreign key
9105: ** violations in the destination database and returns SQLITE_OK.
9106: **
9107: ** In all other cases this function returns SQLITE_MISUSE.
9108: */
9109: int sqlite3changeset_fk_conflicts(
9110: sqlite3_changeset_iter *pIter, /* Changeset iterator */
9111: int *pnOut /* OUT: Number of FK violations */
9112: );
9113:
9114:
9115: /*
9116: ** CAPI3REF: Finalize A Changeset Iterator
9117: **
9118: ** This function is used to finalize an iterator allocated with
9119: ** [sqlite3changeset_start()].
9120: **
9121: ** This function should only be called on iterators created using the
9122: ** [sqlite3changeset_start()] function. If an application calls this
9123: ** function with an iterator passed to a conflict-handler by
9124: ** [sqlite3changeset_apply()], [SQLITE_MISUSE] is immediately returned and the
9125: ** call has no effect.
9126: **
9127: ** If an error was encountered within a call to an sqlite3changeset_xxx()
9128: ** function (for example an [SQLITE_CORRUPT] in [sqlite3changeset_next()] or an
9129: ** [SQLITE_NOMEM] in [sqlite3changeset_new()]) then an error code corresponding
9130: ** to that error is returned by this function. Otherwise, SQLITE_OK is
9131: ** returned. This is to allow the following pattern (pseudo-code):
9132: **
9133: ** sqlite3changeset_start();
9134: ** while( SQLITE_ROW==sqlite3changeset_next() ){
9135: ** // Do something with change.
9136: ** }
9137: ** rc = sqlite3changeset_finalize();
9138: ** if( rc!=SQLITE_OK ){
9139: ** // An error has occurred
9140: ** }
9141: */
9142: int sqlite3changeset_finalize(sqlite3_changeset_iter *pIter);
9143:
9144: /*
9145: ** CAPI3REF: Invert A Changeset
9146: **
9147: ** This function is used to "invert" a changeset object. Applying an inverted
9148: ** changeset to a database reverses the effects of applying the uninverted
9149: ** changeset. Specifically:
9150: **
9151: ** <ul>
9152: ** <li> Each DELETE change is changed to an INSERT, and
9153: ** <li> Each INSERT change is changed to a DELETE, and
9154: ** <li> For each UPDATE change, the old.* and new.* values are exchanged.
9155: ** </ul>
9156: **
9157: ** This function does not change the order in which changes appear within
9158: ** the changeset. It merely reverses the sense of each individual change.
9159: **
9160: ** If successful, a pointer to a buffer containing the inverted changeset
9161: ** is stored in *ppOut, the size of the same buffer is stored in *pnOut, and
9162: ** SQLITE_OK is returned. If an error occurs, both *pnOut and *ppOut are
9163: ** zeroed and an SQLite error code returned.
9164: **
9165: ** It is the responsibility of the caller to eventually call sqlite3_free()
9166: ** on the *ppOut pointer to free the buffer allocation following a successful
9167: ** call to this function.
9168: **
9169: ** WARNING/TODO: This function currently assumes that the input is a valid
9170: ** changeset. If it is not, the results are undefined.
9171: */
9172: int sqlite3changeset_invert(
9173: int nIn, const void *pIn, /* Input changeset */
9174: int *pnOut, void **ppOut /* OUT: Inverse of input */
9175: );
9176:
9177: /*
9178: ** CAPI3REF: Concatenate Two Changeset Objects
9179: **
9180: ** This function is used to concatenate two changesets, A and B, into a
9181: ** single changeset. The result is a changeset equivalent to applying
9182: ** changeset A followed by changeset B.
9183: **
9184: ** This function combines the two input changesets using an
9185: ** sqlite3_changegroup object. Calling it produces similar results as the
9186: ** following code fragment:
9187: **
9188: ** sqlite3_changegroup *pGrp;
9189: ** rc = sqlite3_changegroup_new(&pGrp);
9190: ** if( rc==SQLITE_OK ) rc = sqlite3changegroup_add(pGrp, nA, pA);
9191: ** if( rc==SQLITE_OK ) rc = sqlite3changegroup_add(pGrp, nB, pB);
9192: ** if( rc==SQLITE_OK ){
9193: ** rc = sqlite3changegroup_output(pGrp, pnOut, ppOut);
9194: ** }else{
9195: ** *ppOut = 0;
9196: ** *pnOut = 0;
9197: ** }
9198: **
9199: ** Refer to the sqlite3_changegroup documentation below for details.
9200: */
9201: int sqlite3changeset_concat(
9202: int nA, /* Number of bytes in buffer pA */
9203: void *pA, /* Pointer to buffer containing changeset A */
9204: int nB, /* Number of bytes in buffer pB */
9205: void *pB, /* Pointer to buffer containing changeset B */
9206: int *pnOut, /* OUT: Number of bytes in output changeset */
9207: void **ppOut /* OUT: Buffer containing output changeset */
9208: );
9209:
9210:
9211: /*
9212: ** Changegroup handle.
9213: */
9214: typedef struct sqlite3_changegroup sqlite3_changegroup;
9215:
9216: /*
9217: ** CAPI3REF: Combine two or more changesets into a single changeset.
9218: **
9219: ** An sqlite3_changegroup object is used to combine two or more changesets
9220: ** (or patchsets) into a single changeset (or patchset). A single changegroup
9221: ** object may combine changesets or patchsets, but not both. The output is
9222: ** always in the same format as the input.
9223: **
9224: ** If successful, this function returns SQLITE_OK and populates (*pp) with
9225: ** a pointer to a new sqlite3_changegroup object before returning. The caller
9226: ** should eventually free the returned object using a call to
9227: ** sqlite3changegroup_delete(). If an error occurs, an SQLite error code
9228: ** (i.e. SQLITE_NOMEM) is returned and *pp is set to NULL.
9229: **
9230: ** The usual usage pattern for an sqlite3_changegroup object is as follows:
9231: **
9232: ** <ul>
9233: ** <li> It is created using a call to sqlite3changegroup_new().
9234: **
9235: ** <li> Zero or more changesets (or patchsets) are added to the object
9236: ** by calling sqlite3changegroup_add().
9237: **
9238: ** <li> The result of combining all input changesets together is obtained
9239: ** by the application via a call to sqlite3changegroup_output().
9240: **
9241: ** <li> The object is deleted using a call to sqlite3changegroup_delete().
9242: ** </ul>
9243: **
9244: ** Any number of calls to add() and output() may be made between the calls to
9245: ** new() and delete(), and in any order.
9246: **
9247: ** As well as the regular sqlite3changegroup_add() and
9248: ** sqlite3changegroup_output() functions, also available are the streaming
9249: ** versions sqlite3changegroup_add_strm() and sqlite3changegroup_output_strm().
9250: */
9251: int sqlite3changegroup_new(sqlite3_changegroup **pp);
9252:
9253: /*
9254: ** Add all changes within the changeset (or patchset) in buffer pData (size
9255: ** nData bytes) to the changegroup.
9256: **
9257: ** If the buffer contains a patchset, then all prior calls to this function
9258: ** on the same changegroup object must also have specified patchsets. Or, if
9259: ** the buffer contains a changeset, so must have the earlier calls to this
9260: ** function. Otherwise, SQLITE_ERROR is returned and no changes are added
9261: ** to the changegroup.
9262: **
9263: ** Rows within the changeset and changegroup are identified by the values in
9264: ** their PRIMARY KEY columns. A change in the changeset is considered to
9265: ** apply to the same row as a change already present in the changegroup if
9266: ** the two rows have the same primary key.
9267: **
9268: ** Changes to rows that that do not already appear in the changegroup are
9269: ** simply copied into it. Or, if both the new changeset and the changegroup
9270: ** contain changes that apply to a single row, the final contents of the
9271: ** changegroup depends on the type of each change, as follows:
9272: **
9273: ** <table border=1 style="margin-left:8ex;margin-right:8ex">
9274: ** <tr><th style="white-space:pre">Existing Change </th>
9275: ** <th style="white-space:pre">New Change </th>
9276: ** <th>Output Change
9277: ** <tr><td>INSERT <td>INSERT <td>
9278: ** The new change is ignored. This case does not occur if the new
9279: ** changeset was recorded immediately after the changesets already
9280: ** added to the changegroup.
9281: ** <tr><td>INSERT <td>UPDATE <td>
9282: ** The INSERT change remains in the changegroup. The values in the
9283: ** INSERT change are modified as if the row was inserted by the
9284: ** existing change and then updated according to the new change.
9285: ** <tr><td>INSERT <td>DELETE <td>
9286: ** The existing INSERT is removed from the changegroup. The DELETE is
9287: ** not added.
9288: ** <tr><td>UPDATE <td>INSERT <td>
9289: ** The new change is ignored. This case does not occur if the new
9290: ** changeset was recorded immediately after the changesets already
9291: ** added to the changegroup.
9292: ** <tr><td>UPDATE <td>UPDATE <td>
9293: ** The existing UPDATE remains within the changegroup. It is amended
9294: ** so that the accompanying values are as if the row was updated once
9295: ** by the existing change and then again by the new change.
9296: ** <tr><td>UPDATE <td>DELETE <td>
9297: ** The existing UPDATE is replaced by the new DELETE within the
9298: ** changegroup.
9299: ** <tr><td>DELETE <td>INSERT <td>
9300: ** If one or more of the column values in the row inserted by the
9301: ** new change differ from those in the row deleted by the existing
9302: ** change, the existing DELETE is replaced by an UPDATE within the
9303: ** changegroup. Otherwise, if the inserted row is exactly the same
9304: ** as the deleted row, the existing DELETE is simply discarded.
9305: ** <tr><td>DELETE <td>UPDATE <td>
9306: ** The new change is ignored. This case does not occur if the new
9307: ** changeset was recorded immediately after the changesets already
9308: ** added to the changegroup.
9309: ** <tr><td>DELETE <td>DELETE <td>
9310: ** The new change is ignored. This case does not occur if the new
9311: ** changeset was recorded immediately after the changesets already
9312: ** added to the changegroup.
9313: ** </table>
9314: **
9315: ** If the new changeset contains changes to a table that is already present
9316: ** in the changegroup, then the number of columns and the position of the
9317: ** primary key columns for the table must be consistent. If this is not the
9318: ** case, this function fails with SQLITE_SCHEMA. If the input changeset
9319: ** appears to be corrupt and the corruption is detected, SQLITE_CORRUPT is
9320: ** returned. Or, if an out-of-memory condition occurs during processing, this
9321: ** function returns SQLITE_NOMEM. In all cases, if an error occurs the
9322: ** final contents of the changegroup is undefined.
9323: **
9324: ** If no error occurs, SQLITE_OK is returned.
9325: */
9326: int sqlite3changegroup_add(sqlite3_changegroup*, int nData, void *pData);
9327:
9328: /*
9329: ** Obtain a buffer containing a changeset (or patchset) representing the
9330: ** current contents of the changegroup. If the inputs to the changegroup
9331: ** were themselves changesets, the output is a changeset. Or, if the
9332: ** inputs were patchsets, the output is also a patchset.
9333: **
9334: ** As with the output of the sqlite3session_changeset() and
9335: ** sqlite3session_patchset() functions, all changes related to a single
9336: ** table are grouped together in the output of this function. Tables appear
9337: ** in the same order as for the very first changeset added to the changegroup.
9338: ** If the second or subsequent changesets added to the changegroup contain
9339: ** changes for tables that do not appear in the first changeset, they are
9340: ** appended onto the end of the output changeset, again in the order in
9341: ** which they are first encountered.
9342: **
9343: ** If an error occurs, an SQLite error code is returned and the output
9344: ** variables (*pnData) and (*ppData) are set to 0. Otherwise, SQLITE_OK
9345: ** is returned and the output variables are set to the size of and a
9346: ** pointer to the output buffer, respectively. In this case it is the
9347: ** responsibility of the caller to eventually free the buffer using a
9348: ** call to sqlite3_free().
9349: */
9350: int sqlite3changegroup_output(
9351: sqlite3_changegroup*,
9352: int *pnData, /* OUT: Size of output buffer in bytes */
9353: void **ppData /* OUT: Pointer to output buffer */
9354: );
9355:
9356: /*
9357: ** Delete a changegroup object.
9358: */
9359: void sqlite3changegroup_delete(sqlite3_changegroup*);
9360:
9361: /*
9362: ** CAPI3REF: Apply A Changeset To A Database
9363: **
9364: ** Apply a changeset to a database. This function attempts to update the
9365: ** "main" database attached to handle db with the changes found in the
9366: ** changeset passed via the second and third arguments.
9367: **
9368: ** The fourth argument (xFilter) passed to this function is the "filter
9369: ** callback". If it is not NULL, then for each table affected by at least one
9370: ** change in the changeset, the filter callback is invoked with
9371: ** the table name as the second argument, and a copy of the context pointer
9372: ** passed as the sixth argument to this function as the first. If the "filter
9373: ** callback" returns zero, then no attempt is made to apply any changes to
9374: ** the table. Otherwise, if the return value is non-zero or the xFilter
9375: ** argument to this function is NULL, all changes related to the table are
9376: ** attempted.
9377: **
9378: ** For each table that is not excluded by the filter callback, this function
9379: ** tests that the target database contains a compatible table. A table is
9380: ** considered compatible if all of the following are true:
9381: **
9382: ** <ul>
9383: ** <li> The table has the same name as the name recorded in the
9384: ** changeset, and
9385: ** <li> The table has the same number of columns as recorded in the
9386: ** changeset, and
9387: ** <li> The table has primary key columns in the same position as
9388: ** recorded in the changeset.
9389: ** </ul>
9390: **
9391: ** If there is no compatible table, it is not an error, but none of the
9392: ** changes associated with the table are applied. A warning message is issued
9393: ** via the sqlite3_log() mechanism with the error code SQLITE_SCHEMA. At most
9394: ** one such warning is issued for each table in the changeset.
9395: **
9396: ** For each change for which there is a compatible table, an attempt is made
9397: ** to modify the table contents according to the UPDATE, INSERT or DELETE
9398: ** change. If a change cannot be applied cleanly, the conflict handler
9399: ** function passed as the fifth argument to sqlite3changeset_apply() may be
9400: ** invoked. A description of exactly when the conflict handler is invoked for
9401: ** each type of change is below.
9402: **
9403: ** Unlike the xFilter argument, xConflict may not be passed NULL. The results
9404: ** of passing anything other than a valid function pointer as the xConflict
9405: ** argument are undefined.
9406: **
9407: ** Each time the conflict handler function is invoked, it must return one
9408: ** of [SQLITE_CHANGESET_OMIT], [SQLITE_CHANGESET_ABORT] or
9409: ** [SQLITE_CHANGESET_REPLACE]. SQLITE_CHANGESET_REPLACE may only be returned
9410: ** if the second argument passed to the conflict handler is either
9411: ** SQLITE_CHANGESET_DATA or SQLITE_CHANGESET_CONFLICT. If the conflict-handler
9412: ** returns an illegal value, any changes already made are rolled back and
9413: ** the call to sqlite3changeset_apply() returns SQLITE_MISUSE. Different
9414: ** actions are taken by sqlite3changeset_apply() depending on the value
9415: ** returned by each invocation of the conflict-handler function. Refer to
9416: ** the documentation for the three
9417: ** [SQLITE_CHANGESET_OMIT|available return values] for details.
9418: **
9419: ** <dl>
9420: ** <dt>DELETE Changes<dd>
9421: ** For each DELETE change, this function checks if the target database
9422: ** contains a row with the same primary key value (or values) as the
9423: ** original row values stored in the changeset. If it does, and the values
9424: ** stored in all non-primary key columns also match the values stored in
9425: ** the changeset the row is deleted from the target database.
9426: **
9427: ** If a row with matching primary key values is found, but one or more of
9428: ** the non-primary key fields contains a value different from the original
9429: ** row value stored in the changeset, the conflict-handler function is
9430: ** invoked with [SQLITE_CHANGESET_DATA] as the second argument.
9431: **
9432: ** If no row with matching primary key values is found in the database,
9433: ** the conflict-handler function is invoked with [SQLITE_CHANGESET_NOTFOUND]
9434: ** passed as the second argument.
9435: **
9436: ** If the DELETE operation is attempted, but SQLite returns SQLITE_CONSTRAINT
9437: ** (which can only happen if a foreign key constraint is violated), the
9438: ** conflict-handler function is invoked with [SQLITE_CHANGESET_CONSTRAINT]
9439: ** passed as the second argument. This includes the case where the DELETE
9440: ** operation is attempted because an earlier call to the conflict handler
9441: ** function returned [SQLITE_CHANGESET_REPLACE].
9442: **
9443: ** <dt>INSERT Changes<dd>
9444: ** For each INSERT change, an attempt is made to insert the new row into
9445: ** the database.
9446: **
9447: ** If the attempt to insert the row fails because the database already
9448: ** contains a row with the same primary key values, the conflict handler
9449: ** function is invoked with the second argument set to
9450: ** [SQLITE_CHANGESET_CONFLICT].
9451: **
9452: ** If the attempt to insert the row fails because of some other constraint
9453: ** violation (e.g. NOT NULL or UNIQUE), the conflict handler function is
9454: ** invoked with the second argument set to [SQLITE_CHANGESET_CONSTRAINT].
9455: ** This includes the case where the INSERT operation is re-attempted because
9456: ** an earlier call to the conflict handler function returned
9457: ** [SQLITE_CHANGESET_REPLACE].
9458: **
9459: ** <dt>UPDATE Changes<dd>
9460: ** For each UPDATE change, this function checks if the target database
9461: ** contains a row with the same primary key value (or values) as the
9462: ** original row values stored in the changeset. If it does, and the values
9463: ** stored in all non-primary key columns also match the values stored in
9464: ** the changeset the row is updated within the target database.
9465: **
9466: ** If a row with matching primary key values is found, but one or more of
9467: ** the non-primary key fields contains a value different from an original
9468: ** row value stored in the changeset, the conflict-handler function is
9469: ** invoked with [SQLITE_CHANGESET_DATA] as the second argument. Since
9470: ** UPDATE changes only contain values for non-primary key fields that are
9471: ** to be modified, only those fields need to match the original values to
9472: ** avoid the SQLITE_CHANGESET_DATA conflict-handler callback.
9473: **
9474: ** If no row with matching primary key values is found in the database,
9475: ** the conflict-handler function is invoked with [SQLITE_CHANGESET_NOTFOUND]
9476: ** passed as the second argument.
9477: **
9478: ** If the UPDATE operation is attempted, but SQLite returns
9479: ** SQLITE_CONSTRAINT, the conflict-handler function is invoked with
9480: ** [SQLITE_CHANGESET_CONSTRAINT] passed as the second argument.
9481: ** This includes the case where the UPDATE operation is attempted after
9482: ** an earlier call to the conflict handler function returned
9483: ** [SQLITE_CHANGESET_REPLACE].
9484: ** </dl>
9485: **
9486: ** It is safe to execute SQL statements, including those that write to the
9487: ** table that the callback related to, from within the xConflict callback.
9488: ** This can be used to further customize the applications conflict
9489: ** resolution strategy.
9490: **
9491: ** All changes made by this function are enclosed in a savepoint transaction.
9492: ** If any other error (aside from a constraint failure when attempting to
9493: ** write to the target database) occurs, then the savepoint transaction is
9494: ** rolled back, restoring the target database to its original state, and an
9495: ** SQLite error code returned.
9496: */
9497: int sqlite3changeset_apply(
9498: sqlite3 *db, /* Apply change to "main" db of this handle */
9499: int nChangeset, /* Size of changeset in bytes */
9500: void *pChangeset, /* Changeset blob */
9501: int(*xFilter)(
9502: void *pCtx, /* Copy of sixth arg to _apply() */
9503: const char *zTab /* Table name */
9504: ),
9505: int(*xConflict)(
9506: void *pCtx, /* Copy of sixth arg to _apply() */
9507: int eConflict, /* DATA, MISSING, CONFLICT, CONSTRAINT */
9508: sqlite3_changeset_iter *p /* Handle describing change and conflict */
9509: ),
9510: void *pCtx /* First argument passed to xConflict */
9511: );
9512:
9513: /*
9514: ** CAPI3REF: Constants Passed To The Conflict Handler
9515: **
9516: ** Values that may be passed as the second argument to a conflict-handler.
9517: **
9518: ** <dl>
9519: ** <dt>SQLITE_CHANGESET_DATA<dd>
9520: ** The conflict handler is invoked with CHANGESET_DATA as the second argument
9521: ** when processing a DELETE or UPDATE change if a row with the required
9522: ** PRIMARY KEY fields is present in the database, but one or more other
9523: ** (non primary-key) fields modified by the update do not contain the
9524: ** expected "before" values.
9525: **
9526: ** The conflicting row, in this case, is the database row with the matching
9527: ** primary key.
9528: **
9529: ** <dt>SQLITE_CHANGESET_NOTFOUND<dd>
9530: ** The conflict handler is invoked with CHANGESET_NOTFOUND as the second
9531: ** argument when processing a DELETE or UPDATE change if a row with the
9532: ** required PRIMARY KEY fields is not present in the database.
9533: **
9534: ** There is no conflicting row in this case. The results of invoking the
9535: ** sqlite3changeset_conflict() API are undefined.
9536: **
9537: ** <dt>SQLITE_CHANGESET_CONFLICT<dd>
9538: ** CHANGESET_CONFLICT is passed as the second argument to the conflict
9539: ** handler while processing an INSERT change if the operation would result
9540: ** in duplicate primary key values.
9541: **
9542: ** The conflicting row in this case is the database row with the matching
9543: ** primary key.
9544: **
9545: ** <dt>SQLITE_CHANGESET_FOREIGN_KEY<dd>
9546: ** If foreign key handling is enabled, and applying a changeset leaves the
9547: ** database in a state containing foreign key violations, the conflict
9548: ** handler is invoked with CHANGESET_FOREIGN_KEY as the second argument
9549: ** exactly once before the changeset is committed. If the conflict handler
9550: ** returns CHANGESET_OMIT, the changes, including those that caused the
9551: ** foreign key constraint violation, are committed. Or, if it returns
9552: ** CHANGESET_ABORT, the changeset is rolled back.
9553: **
9554: ** No current or conflicting row information is provided. The only function
9555: ** it is possible to call on the supplied sqlite3_changeset_iter handle
9556: ** is sqlite3changeset_fk_conflicts().
9557: **
9558: ** <dt>SQLITE_CHANGESET_CONSTRAINT<dd>
9559: ** If any other constraint violation occurs while applying a change (i.e.
9560: ** a UNIQUE, CHECK or NOT NULL constraint), the conflict handler is
9561: ** invoked with CHANGESET_CONSTRAINT as the second argument.
9562: **
9563: ** There is no conflicting row in this case. The results of invoking the
9564: ** sqlite3changeset_conflict() API are undefined.
9565: **
9566: ** </dl>
9567: */
9568: #define SQLITE_CHANGESET_DATA 1
9569: #define SQLITE_CHANGESET_NOTFOUND 2
9570: #define SQLITE_CHANGESET_CONFLICT 3
9571: #define SQLITE_CHANGESET_CONSTRAINT 4
9572: #define SQLITE_CHANGESET_FOREIGN_KEY 5
9573:
9574: /*
9575: ** CAPI3REF: Constants Returned By The Conflict Handler
9576: **
9577: ** A conflict handler callback must return one of the following three values.
9578: **
9579: ** <dl>
9580: ** <dt>SQLITE_CHANGESET_OMIT<dd>
9581: ** If a conflict handler returns this value no special action is taken. The
9582: ** change that caused the conflict is not applied. The session module
9583: ** continues to the next change in the changeset.
9584: **
9585: ** <dt>SQLITE_CHANGESET_REPLACE<dd>
9586: ** This value may only be returned if the second argument to the conflict
9587: ** handler was SQLITE_CHANGESET_DATA or SQLITE_CHANGESET_CONFLICT. If this
9588: ** is not the case, any changes applied so far are rolled back and the
9589: ** call to sqlite3changeset_apply() returns SQLITE_MISUSE.
9590: **
9591: ** If CHANGESET_REPLACE is returned by an SQLITE_CHANGESET_DATA conflict
9592: ** handler, then the conflicting row is either updated or deleted, depending
9593: ** on the type of change.
9594: **
9595: ** If CHANGESET_REPLACE is returned by an SQLITE_CHANGESET_CONFLICT conflict
9596: ** handler, then the conflicting row is removed from the database and a
9597: ** second attempt to apply the change is made. If this second attempt fails,
9598: ** the original row is restored to the database before continuing.
9599: **
9600: ** <dt>SQLITE_CHANGESET_ABORT<dd>
9601: ** If this value is returned, any changes applied so far are rolled back
9602: ** and the call to sqlite3changeset_apply() returns SQLITE_ABORT.
9603: ** </dl>
9604: */
9605: #define SQLITE_CHANGESET_OMIT 0
9606: #define SQLITE_CHANGESET_REPLACE 1
9607: #define SQLITE_CHANGESET_ABORT 2
9608:
9609: /*
9610: ** CAPI3REF: Streaming Versions of API functions.
9611: **
9612: ** The six streaming API xxx_strm() functions serve similar purposes to the
9613: ** corresponding non-streaming API functions:
9614: **
9615: ** <table border=1 style="margin-left:8ex;margin-right:8ex">
9616: ** <tr><th>Streaming function<th>Non-streaming equivalent</th>
9617: ** <tr><td>sqlite3changeset_apply_str<td>[sqlite3changeset_apply]
9618: ** <tr><td>sqlite3changeset_concat_str<td>[sqlite3changeset_concat]
9619: ** <tr><td>sqlite3changeset_invert_str<td>[sqlite3changeset_invert]
9620: ** <tr><td>sqlite3changeset_start_str<td>[sqlite3changeset_start]
9621: ** <tr><td>sqlite3session_changeset_str<td>[sqlite3session_changeset]
9622: ** <tr><td>sqlite3session_patchset_str<td>[sqlite3session_patchset]
9623: ** </table>
9624: **
9625: ** Non-streaming functions that accept changesets (or patchsets) as input
9626: ** require that the entire changeset be stored in a single buffer in memory.
9627: ** Similarly, those that return a changeset or patchset do so by returning
9628: ** a pointer to a single large buffer allocated using sqlite3_malloc().
9629: ** Normally this is convenient. However, if an application running in a
9630: ** low-memory environment is required to handle very large changesets, the
9631: ** large contiguous memory allocations required can become onerous.
9632: **
9633: ** In order to avoid this problem, instead of a single large buffer, input
9634: ** is passed to a streaming API functions by way of a callback function that
9635: ** the sessions module invokes to incrementally request input data as it is
9636: ** required. In all cases, a pair of API function parameters such as
9637: **
9638: ** <pre>
9639: ** int nChangeset,
9640: ** void *pChangeset,
9641: ** </pre>
9642: **
9643: ** Is replaced by:
9644: **
9645: ** <pre>
9646: ** int (*xInput)(void *pIn, void *pData, int *pnData),
9647: ** void *pIn,
9648: ** </pre>
9649: **
9650: ** Each time the xInput callback is invoked by the sessions module, the first
9651: ** argument passed is a copy of the supplied pIn context pointer. The second
9652: ** argument, pData, points to a buffer (*pnData) bytes in size. Assuming no
9653: ** error occurs the xInput method should copy up to (*pnData) bytes of data
9654: ** into the buffer and set (*pnData) to the actual number of bytes copied
9655: ** before returning SQLITE_OK. If the input is completely exhausted, (*pnData)
9656: ** should be set to zero to indicate this. Or, if an error occurs, an SQLite
9657: ** error code should be returned. In all cases, if an xInput callback returns
9658: ** an error, all processing is abandoned and the streaming API function
9659: ** returns a copy of the error code to the caller.
9660: **
9661: ** In the case of sqlite3changeset_start_strm(), the xInput callback may be
9662: ** invoked by the sessions module at any point during the lifetime of the
9663: ** iterator. If such an xInput callback returns an error, the iterator enters
9664: ** an error state, whereby all subsequent calls to iterator functions
9665: ** immediately fail with the same error code as returned by xInput.
9666: **
9667: ** Similarly, streaming API functions that return changesets (or patchsets)
9668: ** return them in chunks by way of a callback function instead of via a
9669: ** pointer to a single large buffer. In this case, a pair of parameters such
9670: ** as:
9671: **
9672: ** <pre>
9673: ** int *pnChangeset,
9674: ** void **ppChangeset,
9675: ** </pre>
9676: **
9677: ** Is replaced by:
9678: **
9679: ** <pre>
9680: ** int (*xOutput)(void *pOut, const void *pData, int nData),
9681: ** void *pOut
9682: ** </pre>
9683: **
9684: ** The xOutput callback is invoked zero or more times to return data to
9685: ** the application. The first parameter passed to each call is a copy of the
9686: ** pOut pointer supplied by the application. The second parameter, pData,
9687: ** points to a buffer nData bytes in size containing the chunk of output
9688: ** data being returned. If the xOutput callback successfully processes the
9689: ** supplied data, it should return SQLITE_OK to indicate success. Otherwise,
9690: ** it should return some other SQLite error code. In this case processing
9691: ** is immediately abandoned and the streaming API function returns a copy
9692: ** of the xOutput error code to the application.
9693: **
9694: ** The sessions module never invokes an xOutput callback with the third
9695: ** parameter set to a value less than or equal to zero. Other than this,
9696: ** no guarantees are made as to the size of the chunks of data returned.
9697: */
9698: int sqlite3changeset_apply_strm(
9699: sqlite3 *db, /* Apply change to "main" db of this handle */
9700: int (*xInput)(void *pIn, void *pData, int *pnData), /* Input function */
9701: void *pIn, /* First arg for xInput */
9702: int(*xFilter)(
9703: void *pCtx, /* Copy of sixth arg to _apply() */
9704: const char *zTab /* Table name */
9705: ),
9706: int(*xConflict)(
9707: void *pCtx, /* Copy of sixth arg to _apply() */
9708: int eConflict, /* DATA, MISSING, CONFLICT, CONSTRAINT */
9709: sqlite3_changeset_iter *p /* Handle describing change and conflict */
9710: ),
9711: void *pCtx /* First argument passed to xConflict */
9712: );
9713: int sqlite3changeset_concat_strm(
9714: int (*xInputA)(void *pIn, void *pData, int *pnData),
9715: void *pInA,
9716: int (*xInputB)(void *pIn, void *pData, int *pnData),
9717: void *pInB,
9718: int (*xOutput)(void *pOut, const void *pData, int nData),
9719: void *pOut
9720: );
9721: int sqlite3changeset_invert_strm(
9722: int (*xInput)(void *pIn, void *pData, int *pnData),
9723: void *pIn,
9724: int (*xOutput)(void *pOut, const void *pData, int nData),
9725: void *pOut
9726: );
9727: int sqlite3changeset_start_strm(
9728: sqlite3_changeset_iter **pp,
9729: int (*xInput)(void *pIn, void *pData, int *pnData),
9730: void *pIn
9731: );
9732: int sqlite3session_changeset_strm(
9733: sqlite3_session *pSession,
9734: int (*xOutput)(void *pOut, const void *pData, int nData),
9735: void *pOut
9736: );
9737: int sqlite3session_patchset_strm(
9738: sqlite3_session *pSession,
9739: int (*xOutput)(void *pOut, const void *pData, int nData),
9740: void *pOut
9741: );
9742: int sqlite3changegroup_add_strm(sqlite3_changegroup*,
9743: int (*xInput)(void *pIn, void *pData, int *pnData),
9744: void *pIn
9745: );
9746: int sqlite3changegroup_output_strm(sqlite3_changegroup*,
9747: int (*xOutput)(void *pOut, const void *pData, int nData),
9748: void *pOut
9749: );
9750:
9751:
9752: /*
9753: ** Make sure we can call this stuff from C++.
9754: */
9755: #ifdef __cplusplus
9756: }
9757: #endif
9758:
9759: #endif /* !defined(__SQLITESESSION_H_) && defined(SQLITE_ENABLE_SESSION) */
9760:
9761: /******** End of sqlite3session.h *********/
9762: /******** Begin file fts5.h *********/
9763: /*
9764: ** 2014 May 31
9765: **
9766: ** The author disclaims copyright to this source code. In place of
9767: ** a legal notice, here is a blessing:
9768: **
9769: ** May you do good and not evil.
9770: ** May you find forgiveness for yourself and forgive others.
9771: ** May you share freely, never taking more than you give.
9772: **
9773: ******************************************************************************
9774: **
9775: ** Interfaces to extend FTS5. Using the interfaces defined in this file,
9776: ** FTS5 may be extended with:
9777: **
9778: ** * custom tokenizers, and
9779: ** * custom auxiliary functions.
9780: */
9781:
9782:
9783: #ifndef _FTS5_H
9784: #define _FTS5_H
9785:
9786:
9787: #ifdef __cplusplus
9788: extern "C" {
9789: #endif
9790:
9791: /*************************************************************************
9792: ** CUSTOM AUXILIARY FUNCTIONS
9793: **
9794: ** Virtual table implementations may overload SQL functions by implementing
9795: ** the sqlite3_module.xFindFunction() method.
9796: */
9797:
9798: typedef struct Fts5ExtensionApi Fts5ExtensionApi;
9799: typedef struct Fts5Context Fts5Context;
9800: typedef struct Fts5PhraseIter Fts5PhraseIter;
9801:
9802: typedef void (*fts5_extension_function)(
9803: const Fts5ExtensionApi *pApi, /* API offered by current FTS version */
9804: Fts5Context *pFts, /* First arg to pass to pApi functions */
9805: sqlite3_context *pCtx, /* Context for returning result/error */
9806: int nVal, /* Number of values in apVal[] array */
9807: sqlite3_value **apVal /* Array of trailing arguments */
9808: );
9809:
9810: struct Fts5PhraseIter {
9811: const unsigned char *a;
9812: const unsigned char *b;
9813: };
9814:
9815: /*
9816: ** EXTENSION API FUNCTIONS
9817: **
9818: ** xUserData(pFts):
9819: ** Return a copy of the context pointer the extension function was
9820: ** registered with.
9821: **
9822: ** xColumnTotalSize(pFts, iCol, pnToken):
9823: ** If parameter iCol is less than zero, set output variable *pnToken
9824: ** to the total number of tokens in the FTS5 table. Or, if iCol is
9825: ** non-negative but less than the number of columns in the table, return
9826: ** the total number of tokens in column iCol, considering all rows in
9827: ** the FTS5 table.
9828: **
9829: ** If parameter iCol is greater than or equal to the number of columns
9830: ** in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g.
9831: ** an OOM condition or IO error), an appropriate SQLite error code is
9832: ** returned.
9833: **
9834: ** xColumnCount(pFts):
9835: ** Return the number of columns in the table.
9836: **
9837: ** xColumnSize(pFts, iCol, pnToken):
9838: ** If parameter iCol is less than zero, set output variable *pnToken
9839: ** to the total number of tokens in the current row. Or, if iCol is
9840: ** non-negative but less than the number of columns in the table, set
9841: ** *pnToken to the number of tokens in column iCol of the current row.
9842: **
9843: ** If parameter iCol is greater than or equal to the number of columns
9844: ** in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g.
9845: ** an OOM condition or IO error), an appropriate SQLite error code is
9846: ** returned.
9847: **
9848: ** This function may be quite inefficient if used with an FTS5 table
9849: ** created with the "columnsize=0" option.
9850: **
9851: ** xColumnText:
9852: ** This function attempts to retrieve the text of column iCol of the
9853: ** current document. If successful, (*pz) is set to point to a buffer
9854: ** containing the text in utf-8 encoding, (*pn) is set to the size in bytes
9855: ** (not characters) of the buffer and SQLITE_OK is returned. Otherwise,
9856: ** if an error occurs, an SQLite error code is returned and the final values
9857: ** of (*pz) and (*pn) are undefined.
9858: **
9859: ** xPhraseCount:
9860: ** Returns the number of phrases in the current query expression.
9861: **
9862: ** xPhraseSize:
9863: ** Returns the number of tokens in phrase iPhrase of the query. Phrases
9864: ** are numbered starting from zero.
9865: **
9866: ** xInstCount:
9867: ** Set *pnInst to the total number of occurrences of all phrases within
9868: ** the query within the current row. Return SQLITE_OK if successful, or
9869: ** an error code (i.e. SQLITE_NOMEM) if an error occurs.
9870: **
9871: ** This API can be quite slow if used with an FTS5 table created with the
9872: ** "detail=none" or "detail=column" option. If the FTS5 table is created
9873: ** with either "detail=none" or "detail=column" and "content=" option
9874: ** (i.e. if it is a contentless table), then this API always returns 0.
9875: **
9876: ** xInst:
9877: ** Query for the details of phrase match iIdx within the current row.
9878: ** Phrase matches are numbered starting from zero, so the iIdx argument
9879: ** should be greater than or equal to zero and smaller than the value
9880: ** output by xInstCount().
9881: **
9882: ** Usually, output parameter *piPhrase is set to the phrase number, *piCol
9883: ** to the column in which it occurs and *piOff the token offset of the
9884: ** first token of the phrase. The exception is if the table was created
9885: ** with the offsets=0 option specified. In this case *piOff is always
9886: ** set to -1.
9887: **
9888: ** Returns SQLITE_OK if successful, or an error code (i.e. SQLITE_NOMEM)
9889: ** if an error occurs.
9890: **
9891: ** This API can be quite slow if used with an FTS5 table created with the
9892: ** "detail=none" or "detail=column" option.
9893: **
9894: ** xRowid:
9895: ** Returns the rowid of the current row.
9896: **
9897: ** xTokenize:
9898: ** Tokenize text using the tokenizer belonging to the FTS5 table.
9899: **
9900: ** xQueryPhrase(pFts5, iPhrase, pUserData, xCallback):
9901: ** This API function is used to query the FTS table for phrase iPhrase
9902: ** of the current query. Specifically, a query equivalent to:
9903: **
9904: ** ... FROM ftstable WHERE ftstable MATCH $p ORDER BY rowid
9905: **
9906: ** with $p set to a phrase equivalent to the phrase iPhrase of the
9907: ** current query is executed. Any column filter that applies to
9908: ** phrase iPhrase of the current query is included in $p. For each
9909: ** row visited, the callback function passed as the fourth argument
9910: ** is invoked. The context and API objects passed to the callback
9911: ** function may be used to access the properties of each matched row.
9912: ** Invoking Api.xUserData() returns a copy of the pointer passed as
9913: ** the third argument to pUserData.
9914: **
9915: ** If the callback function returns any value other than SQLITE_OK, the
9916: ** query is abandoned and the xQueryPhrase function returns immediately.
9917: ** If the returned value is SQLITE_DONE, xQueryPhrase returns SQLITE_OK.
9918: ** Otherwise, the error code is propagated upwards.
9919: **
9920: ** If the query runs to completion without incident, SQLITE_OK is returned.
9921: ** Or, if some error occurs before the query completes or is aborted by
9922: ** the callback, an SQLite error code is returned.
9923: **
9924: **
9925: ** xSetAuxdata(pFts5, pAux, xDelete)
9926: **
9927: ** Save the pointer passed as the second argument as the extension functions
9928: ** "auxiliary data". The pointer may then be retrieved by the current or any
9929: ** future invocation of the same fts5 extension function made as part of
9930: ** of the same MATCH query using the xGetAuxdata() API.
9931: **
9932: ** Each extension function is allocated a single auxiliary data slot for
9933: ** each FTS query (MATCH expression). If the extension function is invoked
9934: ** more than once for a single FTS query, then all invocations share a
9935: ** single auxiliary data context.
9936: **
9937: ** If there is already an auxiliary data pointer when this function is
9938: ** invoked, then it is replaced by the new pointer. If an xDelete callback
9939: ** was specified along with the original pointer, it is invoked at this
9940: ** point.
9941: **
9942: ** The xDelete callback, if one is specified, is also invoked on the
9943: ** auxiliary data pointer after the FTS5 query has finished.
9944: **
9945: ** If an error (e.g. an OOM condition) occurs within this function, an
9946: ** the auxiliary data is set to NULL and an error code returned. If the
9947: ** xDelete parameter was not NULL, it is invoked on the auxiliary data
9948: ** pointer before returning.
9949: **
9950: **
9951: ** xGetAuxdata(pFts5, bClear)
9952: **
9953: ** Returns the current auxiliary data pointer for the fts5 extension
9954: ** function. See the xSetAuxdata() method for details.
9955: **
9956: ** If the bClear argument is non-zero, then the auxiliary data is cleared
9957: ** (set to NULL) before this function returns. In this case the xDelete,
9958: ** if any, is not invoked.
9959: **
9960: **
9961: ** xRowCount(pFts5, pnRow)
9962: **
9963: ** This function is used to retrieve the total number of rows in the table.
9964: ** In other words, the same value that would be returned by:
9965: **
9966: ** SELECT count(*) FROM ftstable;
9967: **
9968: ** xPhraseFirst()
9969: ** This function is used, along with type Fts5PhraseIter and the xPhraseNext
9970: ** method, to iterate through all instances of a single query phrase within
9971: ** the current row. This is the same information as is accessible via the
9972: ** xInstCount/xInst APIs. While the xInstCount/xInst APIs are more convenient
9973: ** to use, this API may be faster under some circumstances. To iterate
9974: ** through instances of phrase iPhrase, use the following code:
9975: **
9976: ** Fts5PhraseIter iter;
9977: ** int iCol, iOff;
9978: ** for(pApi->xPhraseFirst(pFts, iPhrase, &iter, &iCol, &iOff);
9979: ** iCol>=0;
9980: ** pApi->xPhraseNext(pFts, &iter, &iCol, &iOff)
9981: ** ){
9982: ** // An instance of phrase iPhrase at offset iOff of column iCol
9983: ** }
9984: **
9985: ** The Fts5PhraseIter structure is defined above. Applications should not
9986: ** modify this structure directly - it should only be used as shown above
9987: ** with the xPhraseFirst() and xPhraseNext() API methods (and by
9988: ** xPhraseFirstColumn() and xPhraseNextColumn() as illustrated below).
9989: **
9990: ** This API can be quite slow if used with an FTS5 table created with the
9991: ** "detail=none" or "detail=column" option. If the FTS5 table is created
9992: ** with either "detail=none" or "detail=column" and "content=" option
9993: ** (i.e. if it is a contentless table), then this API always iterates
9994: ** through an empty set (all calls to xPhraseFirst() set iCol to -1).
9995: **
9996: ** xPhraseNext()
9997: ** See xPhraseFirst above.
9998: **
9999: ** xPhraseFirstColumn()
10000: ** This function and xPhraseNextColumn() are similar to the xPhraseFirst()
10001: ** and xPhraseNext() APIs described above. The difference is that instead
10002: ** of iterating through all instances of a phrase in the current row, these
10003: ** APIs are used to iterate through the set of columns in the current row
10004: ** that contain one or more instances of a specified phrase. For example:
10005: **
10006: ** Fts5PhraseIter iter;
10007: ** int iCol;
10008: ** for(pApi->xPhraseFirstColumn(pFts, iPhrase, &iter, &iCol);
10009: ** iCol>=0;
10010: ** pApi->xPhraseNextColumn(pFts, &iter, &iCol)
10011: ** ){
10012: ** // Column iCol contains at least one instance of phrase iPhrase
10013: ** }
10014: **
10015: ** This API can be quite slow if used with an FTS5 table created with the
10016: ** "detail=none" option. If the FTS5 table is created with either
10017: ** "detail=none" "content=" option (i.e. if it is a contentless table),
10018: ** then this API always iterates through an empty set (all calls to
10019: ** xPhraseFirstColumn() set iCol to -1).
10020: **
10021: ** The information accessed using this API and its companion
10022: ** xPhraseFirstColumn() may also be obtained using xPhraseFirst/xPhraseNext
10023: ** (or xInst/xInstCount). The chief advantage of this API is that it is
10024: ** significantly more efficient than those alternatives when used with
10025: ** "detail=column" tables.
10026: **
10027: ** xPhraseNextColumn()
10028: ** See xPhraseFirstColumn above.
10029: */
10030: struct Fts5ExtensionApi {
10031: int iVersion; /* Currently always set to 3 */
10032:
10033: void *(*xUserData)(Fts5Context*);
10034:
10035: int (*xColumnCount)(Fts5Context*);
10036: int (*xRowCount)(Fts5Context*, sqlite3_int64 *pnRow);
10037: int (*xColumnTotalSize)(Fts5Context*, int iCol, sqlite3_int64 *pnToken);
10038:
10039: int (*xTokenize)(Fts5Context*,
10040: const char *pText, int nText, /* Text to tokenize */
10041: void *pCtx, /* Context passed to xToken() */
10042: int (*xToken)(void*, int, const char*, int, int, int) /* Callback */
10043: );
10044:
10045: int (*xPhraseCount)(Fts5Context*);
10046: int (*xPhraseSize)(Fts5Context*, int iPhrase);
10047:
10048: int (*xInstCount)(Fts5Context*, int *pnInst);
10049: int (*xInst)(Fts5Context*, int iIdx, int *piPhrase, int *piCol, int *piOff);
10050:
10051: sqlite3_int64 (*xRowid)(Fts5Context*);
10052: int (*xColumnText)(Fts5Context*, int iCol, const char **pz, int *pn);
10053: int (*xColumnSize)(Fts5Context*, int iCol, int *pnToken);
10054:
10055: int (*xQueryPhrase)(Fts5Context*, int iPhrase, void *pUserData,
10056: int(*)(const Fts5ExtensionApi*,Fts5Context*,void*)
10057: );
10058: int (*xSetAuxdata)(Fts5Context*, void *pAux, void(*xDelete)(void*));
10059: void *(*xGetAuxdata)(Fts5Context*, int bClear);
10060:
10061: int (*xPhraseFirst)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*, int*);
10062: void (*xPhraseNext)(Fts5Context*, Fts5PhraseIter*, int *piCol, int *piOff);
10063:
10064: int (*xPhraseFirstColumn)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*);
10065: void (*xPhraseNextColumn)(Fts5Context*, Fts5PhraseIter*, int *piCol);
10066: };
10067:
10068: /*
10069: ** CUSTOM AUXILIARY FUNCTIONS
10070: *************************************************************************/
10071:
10072: /*************************************************************************
10073: ** CUSTOM TOKENIZERS
10074: **
10075: ** Applications may also register custom tokenizer types. A tokenizer
10076: ** is registered by providing fts5 with a populated instance of the
10077: ** following structure. All structure methods must be defined, setting
10078: ** any member of the fts5_tokenizer struct to NULL leads to undefined
10079: ** behaviour. The structure methods are expected to function as follows:
10080: **
10081: ** xCreate:
10082: ** This function is used to allocate and initialize a tokenizer instance.
10083: ** A tokenizer instance is required to actually tokenize text.
10084: **
10085: ** The first argument passed to this function is a copy of the (void*)
10086: ** pointer provided by the application when the fts5_tokenizer object
10087: ** was registered with FTS5 (the third argument to xCreateTokenizer()).
10088: ** The second and third arguments are an array of nul-terminated strings
10089: ** containing the tokenizer arguments, if any, specified following the
10090: ** tokenizer name as part of the CREATE VIRTUAL TABLE statement used
10091: ** to create the FTS5 table.
10092: **
10093: ** The final argument is an output variable. If successful, (*ppOut)
10094: ** should be set to point to the new tokenizer handle and SQLITE_OK
10095: ** returned. If an error occurs, some value other than SQLITE_OK should
10096: ** be returned. In this case, fts5 assumes that the final value of *ppOut
10097: ** is undefined.
10098: **
10099: ** xDelete:
10100: ** This function is invoked to delete a tokenizer handle previously
10101: ** allocated using xCreate(). Fts5 guarantees that this function will
10102: ** be invoked exactly once for each successful call to xCreate().
10103: **
10104: ** xTokenize:
10105: ** This function is expected to tokenize the nText byte string indicated
10106: ** by argument pText. pText may or may not be nul-terminated. The first
10107: ** argument passed to this function is a pointer to an Fts5Tokenizer object
10108: ** returned by an earlier call to xCreate().
10109: **
10110: ** The second argument indicates the reason that FTS5 is requesting
10111: ** tokenization of the supplied text. This is always one of the following
10112: ** four values:
10113: **
10114: ** <ul><li> <b>FTS5_TOKENIZE_DOCUMENT</b> - A document is being inserted into
10115: ** or removed from the FTS table. The tokenizer is being invoked to
10116: ** determine the set of tokens to add to (or delete from) the
10117: ** FTS index.
10118: **
10119: ** <li> <b>FTS5_TOKENIZE_QUERY</b> - A MATCH query is being executed
10120: ** against the FTS index. The tokenizer is being called to tokenize
10121: ** a bareword or quoted string specified as part of the query.
10122: **
10123: ** <li> <b>(FTS5_TOKENIZE_QUERY | FTS5_TOKENIZE_PREFIX)</b> - Same as
10124: ** FTS5_TOKENIZE_QUERY, except that the bareword or quoted string is
10125: ** followed by a "*" character, indicating that the last token
10126: ** returned by the tokenizer will be treated as a token prefix.
10127: **
10128: ** <li> <b>FTS5_TOKENIZE_AUX</b> - The tokenizer is being invoked to
10129: ** satisfy an fts5_api.xTokenize() request made by an auxiliary
10130: ** function. Or an fts5_api.xColumnSize() request made by the same
10131: ** on a columnsize=0 database.
10132: ** </ul>
10133: **
10134: ** For each token in the input string, the supplied callback xToken() must
10135: ** be invoked. The first argument to it should be a copy of the pointer
10136: ** passed as the second argument to xTokenize(). The third and fourth
10137: ** arguments are a pointer to a buffer containing the token text, and the
10138: ** size of the token in bytes. The 4th and 5th arguments are the byte offsets
10139: ** of the first byte of and first byte immediately following the text from
10140: ** which the token is derived within the input.
10141: **
10142: ** The second argument passed to the xToken() callback ("tflags") should
10143: ** normally be set to 0. The exception is if the tokenizer supports
10144: ** synonyms. In this case see the discussion below for details.
10145: **
10146: ** FTS5 assumes the xToken() callback is invoked for each token in the
10147: ** order that they occur within the input text.
10148: **
10149: ** If an xToken() callback returns any value other than SQLITE_OK, then
10150: ** the tokenization should be abandoned and the xTokenize() method should
10151: ** immediately return a copy of the xToken() return value. Or, if the
10152: ** input buffer is exhausted, xTokenize() should return SQLITE_OK. Finally,
10153: ** if an error occurs with the xTokenize() implementation itself, it
10154: ** may abandon the tokenization and return any error code other than
10155: ** SQLITE_OK or SQLITE_DONE.
10156: **
10157: ** SYNONYM SUPPORT
10158: **
10159: ** Custom tokenizers may also support synonyms. Consider a case in which a
10160: ** user wishes to query for a phrase such as "first place". Using the
10161: ** built-in tokenizers, the FTS5 query 'first + place' will match instances
10162: ** of "first place" within the document set, but not alternative forms
10163: ** such as "1st place". In some applications, it would be better to match
10164: ** all instances of "first place" or "1st place" regardless of which form
10165: ** the user specified in the MATCH query text.
10166: **
10167: ** There are several ways to approach this in FTS5:
10168: **
10169: ** <ol><li> By mapping all synonyms to a single token. In this case, the
10170: ** In the above example, this means that the tokenizer returns the
10171: ** same token for inputs "first" and "1st". Say that token is in
10172: ** fact "first", so that when the user inserts the document "I won
10173: ** 1st place" entries are added to the index for tokens "i", "won",
10174: ** "first" and "place". If the user then queries for '1st + place',
10175: ** the tokenizer substitutes "first" for "1st" and the query works
10176: ** as expected.
10177: **
10178: ** <li> By adding multiple synonyms for a single term to the FTS index.
10179: ** In this case, when tokenizing query text, the tokenizer may
10180: ** provide multiple synonyms for a single term within the document.
10181: ** FTS5 then queries the index for each synonym individually. For
10182: ** example, faced with the query:
10183: **
10184: ** <codeblock>
10185: ** ... MATCH 'first place'</codeblock>
10186: **
10187: ** the tokenizer offers both "1st" and "first" as synonyms for the
10188: ** first token in the MATCH query and FTS5 effectively runs a query
10189: ** similar to:
10190: **
10191: ** <codeblock>
10192: ** ... MATCH '(first OR 1st) place'</codeblock>
10193: **
10194: ** except that, for the purposes of auxiliary functions, the query
10195: ** still appears to contain just two phrases - "(first OR 1st)"
10196: ** being treated as a single phrase.
10197: **
10198: ** <li> By adding multiple synonyms for a single term to the FTS index.
10199: ** Using this method, when tokenizing document text, the tokenizer
10200: ** provides multiple synonyms for each token. So that when a
10201: ** document such as "I won first place" is tokenized, entries are
10202: ** added to the FTS index for "i", "won", "first", "1st" and
10203: ** "place".
10204: **
10205: ** This way, even if the tokenizer does not provide synonyms
10206: ** when tokenizing query text (it should not - to do would be
10207: ** inefficient), it doesn't matter if the user queries for
10208: ** 'first + place' or '1st + place', as there are entires in the
10209: ** FTS index corresponding to both forms of the first token.
10210: ** </ol>
10211: **
10212: ** Whether it is parsing document or query text, any call to xToken that
10213: ** specifies a <i>tflags</i> argument with the FTS5_TOKEN_COLOCATED bit
10214: ** is considered to supply a synonym for the previous token. For example,
10215: ** when parsing the document "I won first place", a tokenizer that supports
10216: ** synonyms would call xToken() 5 times, as follows:
10217: **
10218: ** <codeblock>
10219: ** xToken(pCtx, 0, "i", 1, 0, 1);
10220: ** xToken(pCtx, 0, "won", 3, 2, 5);
10221: ** xToken(pCtx, 0, "first", 5, 6, 11);
10222: ** xToken(pCtx, FTS5_TOKEN_COLOCATED, "1st", 3, 6, 11);
10223: ** xToken(pCtx, 0, "place", 5, 12, 17);
10224: **</codeblock>
10225: **
10226: ** It is an error to specify the FTS5_TOKEN_COLOCATED flag the first time
10227: ** xToken() is called. Multiple synonyms may be specified for a single token
10228: ** by making multiple calls to xToken(FTS5_TOKEN_COLOCATED) in sequence.
10229: ** There is no limit to the number of synonyms that may be provided for a
10230: ** single token.
10231: **
10232: ** In many cases, method (1) above is the best approach. It does not add
10233: ** extra data to the FTS index or require FTS5 to query for multiple terms,
10234: ** so it is efficient in terms of disk space and query speed. However, it
10235: ** does not support prefix queries very well. If, as suggested above, the
10236: ** token "first" is subsituted for "1st" by the tokenizer, then the query:
10237: **
10238: ** <codeblock>
10239: ** ... MATCH '1s*'</codeblock>
10240: **
10241: ** will not match documents that contain the token "1st" (as the tokenizer
10242: ** will probably not map "1s" to any prefix of "first").
10243: **
10244: ** For full prefix support, method (3) may be preferred. In this case,
10245: ** because the index contains entries for both "first" and "1st", prefix
10246: ** queries such as 'fi*' or '1s*' will match correctly. However, because
10247: ** extra entries are added to the FTS index, this method uses more space
10248: ** within the database.
10249: **
10250: ** Method (2) offers a midpoint between (1) and (3). Using this method,
10251: ** a query such as '1s*' will match documents that contain the literal
10252: ** token "1st", but not "first" (assuming the tokenizer is not able to
10253: ** provide synonyms for prefixes). However, a non-prefix query like '1st'
10254: ** will match against "1st" and "first". This method does not require
10255: ** extra disk space, as no extra entries are added to the FTS index.
10256: ** On the other hand, it may require more CPU cycles to run MATCH queries,
10257: ** as separate queries of the FTS index are required for each synonym.
10258: **
10259: ** When using methods (2) or (3), it is important that the tokenizer only
10260: ** provide synonyms when tokenizing document text (method (2)) or query
10261: ** text (method (3)), not both. Doing so will not cause any errors, but is
10262: ** inefficient.
10263: */
10264: typedef struct Fts5Tokenizer Fts5Tokenizer;
10265: typedef struct fts5_tokenizer fts5_tokenizer;
10266: struct fts5_tokenizer {
10267: int (*xCreate)(void*, const char **azArg, int nArg, Fts5Tokenizer **ppOut);
10268: void (*xDelete)(Fts5Tokenizer*);
10269: int (*xTokenize)(Fts5Tokenizer*,
10270: void *pCtx,
10271: int flags, /* Mask of FTS5_TOKENIZE_* flags */
10272: const char *pText, int nText,
10273: int (*xToken)(
10274: void *pCtx, /* Copy of 2nd argument to xTokenize() */
10275: int tflags, /* Mask of FTS5_TOKEN_* flags */
10276: const char *pToken, /* Pointer to buffer containing token */
10277: int nToken, /* Size of token in bytes */
10278: int iStart, /* Byte offset of token within input text */
10279: int iEnd /* Byte offset of end of token within input text */
10280: )
10281: );
10282: };
10283:
10284: /* Flags that may be passed as the third argument to xTokenize() */
10285: #define FTS5_TOKENIZE_QUERY 0x0001
10286: #define FTS5_TOKENIZE_PREFIX 0x0002
10287: #define FTS5_TOKENIZE_DOCUMENT 0x0004
10288: #define FTS5_TOKENIZE_AUX 0x0008
10289:
10290: /* Flags that may be passed by the tokenizer implementation back to FTS5
10291: ** as the third argument to the supplied xToken callback. */
10292: #define FTS5_TOKEN_COLOCATED 0x0001 /* Same position as prev. token */
10293:
10294: /*
10295: ** END OF CUSTOM TOKENIZERS
10296: *************************************************************************/
10297:
10298: /*************************************************************************
10299: ** FTS5 EXTENSION REGISTRATION API
10300: */
10301: typedef struct fts5_api fts5_api;
10302: struct fts5_api {
10303: int iVersion; /* Currently always set to 2 */
10304:
10305: /* Create a new tokenizer */
10306: int (*xCreateTokenizer)(
10307: fts5_api *pApi,
10308: const char *zName,
10309: void *pContext,
10310: fts5_tokenizer *pTokenizer,
10311: void (*xDestroy)(void*)
10312: );
10313:
10314: /* Find an existing tokenizer */
10315: int (*xFindTokenizer)(
10316: fts5_api *pApi,
10317: const char *zName,
10318: void **ppContext,
10319: fts5_tokenizer *pTokenizer
10320: );
10321:
10322: /* Create a new auxiliary function */
10323: int (*xCreateFunction)(
10324: fts5_api *pApi,
10325: const char *zName,
10326: void *pContext,
10327: fts5_extension_function xFunction,
10328: void (*xDestroy)(void*)
10329: );
10330: };
10331:
10332: /*
10333: ** END OF REGISTRATION API
10334: *************************************************************************/
10335:
10336: #ifdef __cplusplus
10337: } /* end of the 'extern "C"' block */
10338: #endif
10339:
10340: #endif /* _FTS5_H */
10341:
10342: /******** End of fts5.h *********/
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