Annotation of embedaddon/php/ext/sqlite/libsqlite/src/vdbeInt.h, revision 1.1.1.1
1.1 misho 1: /*
2: ** 2003 September 6
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 is the header file for information that is private to the
13: ** VDBE. This information used to all be at the top of the single
14: ** source code file "vdbe.c". When that file became too big (over
15: ** 6000 lines long) it was split up into several smaller files and
16: ** this header information was factored out.
17: */
18:
19: /*
20: ** When converting from the native format to the key format and back
21: ** again, in addition to changing the byte order we invert the high-order
22: ** bit of the most significant byte. This causes negative numbers to
23: ** sort before positive numbers in the memcmp() function.
24: */
25: #define keyToInt(X) (sqliteVdbeByteSwap(X) ^ 0x80000000)
26: #define intToKey(X) (sqliteVdbeByteSwap((X) ^ 0x80000000))
27:
28: /*
29: ** The makefile scans this source file and creates the following
30: ** array of string constants which are the names of all VDBE opcodes.
31: ** This array is defined in a separate source code file named opcode.c
32: ** which is automatically generated by the makefile.
33: */
34: extern char *sqliteOpcodeNames[];
35:
36: /*
37: ** SQL is translated into a sequence of instructions to be
38: ** executed by a virtual machine. Each instruction is an instance
39: ** of the following structure.
40: */
41: typedef struct VdbeOp Op;
42:
43: /*
44: ** Boolean values
45: */
46: typedef unsigned char Bool;
47:
48: /*
49: ** A cursor is a pointer into a single BTree within a database file.
50: ** The cursor can seek to a BTree entry with a particular key, or
51: ** loop over all entries of the Btree. You can also insert new BTree
52: ** entries or retrieve the key or data from the entry that the cursor
53: ** is currently pointing to.
54: **
55: ** Every cursor that the virtual machine has open is represented by an
56: ** instance of the following structure.
57: **
58: ** If the Cursor.isTriggerRow flag is set it means that this cursor is
59: ** really a single row that represents the NEW or OLD pseudo-table of
60: ** a row trigger. The data for the row is stored in Cursor.pData and
61: ** the rowid is in Cursor.iKey.
62: */
63: struct Cursor {
64: BtCursor *pCursor; /* The cursor structure of the backend */
65: int lastRecno; /* Last recno from a Next or NextIdx operation */
66: int nextRowid; /* Next rowid returned by OP_NewRowid */
67: Bool recnoIsValid; /* True if lastRecno is valid */
68: Bool keyAsData; /* The OP_Column command works on key instead of data */
69: Bool atFirst; /* True if pointing to first entry */
70: Bool useRandomRowid; /* Generate new record numbers semi-randomly */
71: Bool nullRow; /* True if pointing to a row with no data */
72: Bool nextRowidValid; /* True if the nextRowid field is valid */
73: Bool pseudoTable; /* This is a NEW or OLD pseudo-tables of a trigger */
74: Bool deferredMoveto; /* A call to sqliteBtreeMoveto() is needed */
75: int movetoTarget; /* Argument to the deferred sqliteBtreeMoveto() */
76: Btree *pBt; /* Separate file holding temporary table */
77: int nData; /* Number of bytes in pData */
78: char *pData; /* Data for a NEW or OLD pseudo-table */
79: int iKey; /* Key for the NEW or OLD pseudo-table row */
80: };
81: typedef struct Cursor Cursor;
82:
83: /*
84: ** A sorter builds a list of elements to be sorted. Each element of
85: ** the list is an instance of the following structure.
86: */
87: typedef struct Sorter Sorter;
88: struct Sorter {
89: int nKey; /* Number of bytes in the key */
90: char *zKey; /* The key by which we will sort */
91: int nData; /* Number of bytes in the data */
92: char *pData; /* The data associated with this key */
93: Sorter *pNext; /* Next in the list */
94: };
95:
96: /*
97: ** Number of buckets used for merge-sort.
98: */
99: #define NSORT 30
100:
101: /*
102: ** Number of bytes of string storage space available to each stack
103: ** layer without having to malloc. NBFS is short for Number of Bytes
104: ** For Strings.
105: */
106: #define NBFS 32
107:
108: /*
109: ** A single level of the stack or a single memory cell
110: ** is an instance of the following structure.
111: */
112: struct Mem {
113: int i; /* Integer value */
114: int n; /* Number of characters in string value, including '\0' */
115: int flags; /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */
116: double r; /* Real value */
117: char *z; /* String value */
118: char zShort[NBFS]; /* Space for short strings */
119: };
120: typedef struct Mem Mem;
121:
122: /*
123: ** Allowed values for Mem.flags
124: */
125: #define MEM_Null 0x0001 /* Value is NULL */
126: #define MEM_Str 0x0002 /* Value is a string */
127: #define MEM_Int 0x0004 /* Value is an integer */
128: #define MEM_Real 0x0008 /* Value is a real number */
129: #define MEM_Dyn 0x0010 /* Need to call sqliteFree() on Mem.z */
130: #define MEM_Static 0x0020 /* Mem.z points to a static string */
131: #define MEM_Ephem 0x0040 /* Mem.z points to an ephemeral string */
132: #define MEM_Short 0x0080 /* Mem.z points to Mem.zShort */
133:
134: /* The following MEM_ value appears only in AggElem.aMem.s.flag fields.
135: ** It indicates that the corresponding AggElem.aMem.z points to a
136: ** aggregate function context that needs to be finalized.
137: */
138: #define MEM_AggCtx 0x0100 /* Mem.z points to an agg function context */
139:
140: /*
141: ** The "context" argument for a installable function. A pointer to an
142: ** instance of this structure is the first argument to the routines used
143: ** implement the SQL functions.
144: **
145: ** There is a typedef for this structure in sqlite.h. So all routines,
146: ** even the public interface to SQLite, can use a pointer to this structure.
147: ** But this file is the only place where the internal details of this
148: ** structure are known.
149: **
150: ** This structure is defined inside of vdbe.c because it uses substructures
151: ** (Mem) which are only defined there.
152: */
153: struct sqlite_func {
154: FuncDef *pFunc; /* Pointer to function information. MUST BE FIRST */
155: Mem s; /* The return value is stored here */
156: void *pAgg; /* Aggregate context */
157: u8 isError; /* Set to true for an error */
158: u8 isStep; /* Current in the step function */
159: int cnt; /* Number of times that the step function has been called */
160: };
161:
162: /*
163: ** An Agg structure describes an Aggregator. Each Agg consists of
164: ** zero or more Aggregator elements (AggElem). Each AggElem contains
165: ** a key and one or more values. The values are used in processing
166: ** aggregate functions in a SELECT. The key is used to implement
167: ** the GROUP BY clause of a select.
168: */
169: typedef struct Agg Agg;
170: typedef struct AggElem AggElem;
171: struct Agg {
172: int nMem; /* Number of values stored in each AggElem */
173: AggElem *pCurrent; /* The AggElem currently in focus */
174: HashElem *pSearch; /* The hash element for pCurrent */
175: Hash hash; /* Hash table of all aggregate elements */
176: FuncDef **apFunc; /* Information about aggregate functions */
177: };
178: struct AggElem {
179: char *zKey; /* The key to this AggElem */
180: int nKey; /* Number of bytes in the key, including '\0' at end */
181: Mem aMem[1]; /* The values for this AggElem */
182: };
183:
184: /*
185: ** A Set structure is used for quick testing to see if a value
186: ** is part of a small set. Sets are used to implement code like
187: ** this:
188: ** x.y IN ('hi','hoo','hum')
189: */
190: typedef struct Set Set;
191: struct Set {
192: Hash hash; /* A set is just a hash table */
193: HashElem *prev; /* Previously accessed hash elemen */
194: };
195:
196: /*
197: ** A Keylist is a bunch of keys into a table. The keylist can
198: ** grow without bound. The keylist stores the ROWIDs of database
199: ** records that need to be deleted or updated.
200: */
201: typedef struct Keylist Keylist;
202: struct Keylist {
203: int nKey; /* Number of slots in aKey[] */
204: int nUsed; /* Next unwritten slot in aKey[] */
205: int nRead; /* Next unread slot in aKey[] */
206: Keylist *pNext; /* Next block of keys */
207: int aKey[1]; /* One or more keys. Extra space allocated as needed */
208: };
209:
210: /*
211: ** A Context stores the last insert rowid, the last statement change count,
212: ** and the current statement change count (i.e. changes since last statement).
213: ** Elements of Context structure type make up the ContextStack, which is
214: ** updated by the ContextPush and ContextPop opcodes (used by triggers)
215: */
216: typedef struct Context Context;
217: struct Context {
218: int lastRowid; /* Last insert rowid (from db->lastRowid) */
219: int lsChange; /* Last statement change count (from db->lsChange) */
220: int csChange; /* Current statement change count (from db->csChange) */
221: };
222:
223: /*
224: ** An instance of the virtual machine. This structure contains the complete
225: ** state of the virtual machine.
226: **
227: ** The "sqlite_vm" structure pointer that is returned by sqlite_compile()
228: ** is really a pointer to an instance of this structure.
229: */
230: struct Vdbe {
231: sqlite *db; /* The whole database */
232: Vdbe *pPrev,*pNext; /* Linked list of VDBEs with the same Vdbe.db */
233: FILE *trace; /* Write an execution trace here, if not NULL */
234: int nOp; /* Number of instructions in the program */
235: int nOpAlloc; /* Number of slots allocated for aOp[] */
236: Op *aOp; /* Space to hold the virtual machine's program */
237: int nLabel; /* Number of labels used */
238: int nLabelAlloc; /* Number of slots allocated in aLabel[] */
239: int *aLabel; /* Space to hold the labels */
240: Mem *aStack; /* The operand stack, except string values */
241: Mem *pTos; /* Top entry in the operand stack */
242: char **zArgv; /* Text values used by the callback */
243: char **azColName; /* Becomes the 4th parameter to callbacks */
244: int nCursor; /* Number of slots in aCsr[] */
245: Cursor *aCsr; /* One element of this array for each open cursor */
246: Sorter *pSort; /* A linked list of objects to be sorted */
247: FILE *pFile; /* At most one open file handler */
248: int nField; /* Number of file fields */
249: char **azField; /* Data for each file field */
250: int nVar; /* Number of entries in azVariable[] */
251: char **azVar; /* Values for the OP_Variable opcode */
252: int *anVar; /* Length of each value in azVariable[] */
253: u8 *abVar; /* TRUE if azVariable[i] needs to be sqliteFree()ed */
254: char *zLine; /* A single line from the input file */
255: int nLineAlloc; /* Number of spaces allocated for zLine */
256: int magic; /* Magic number for sanity checking */
257: int nMem; /* Number of memory locations currently allocated */
258: Mem *aMem; /* The memory locations */
259: Agg agg; /* Aggregate information */
260: int nSet; /* Number of sets allocated */
261: Set *aSet; /* An array of sets */
262: int nCallback; /* Number of callbacks invoked so far */
263: Keylist *pList; /* A list of ROWIDs */
264: int keylistStackDepth; /* The size of the "keylist" stack */
265: Keylist **keylistStack; /* The stack used by opcodes ListPush & ListPop */
266: int contextStackDepth; /* The size of the "context" stack */
267: Context *contextStack; /* Stack used by opcodes ContextPush & ContextPop*/
268: int pc; /* The program counter */
269: int rc; /* Value to return */
270: unsigned uniqueCnt; /* Used by OP_MakeRecord when P2!=0 */
271: int errorAction; /* Recovery action to do in case of an error */
272: int undoTransOnError; /* If error, either ROLLBACK or COMMIT */
273: int inTempTrans; /* True if temp database is transactioned */
274: int returnStack[100]; /* Return address stack for OP_Gosub & OP_Return */
275: int returnDepth; /* Next unused element in returnStack[] */
276: int nResColumn; /* Number of columns in one row of the result set */
277: char **azResColumn; /* Values for one row of result */
278: int popStack; /* Pop the stack this much on entry to VdbeExec() */
279: char *zErrMsg; /* Error message written here */
280: u8 explain; /* True if EXPLAIN present on SQL command */
281: };
282:
283: /*
284: ** The following are allowed values for Vdbe.magic
285: */
286: #define VDBE_MAGIC_INIT 0x26bceaa5 /* Building a VDBE program */
287: #define VDBE_MAGIC_RUN 0xbdf20da3 /* VDBE is ready to execute */
288: #define VDBE_MAGIC_HALT 0x519c2973 /* VDBE has completed execution */
289: #define VDBE_MAGIC_DEAD 0xb606c3c8 /* The VDBE has been deallocated */
290:
291: /*
292: ** Function prototypes
293: */
294: void sqliteVdbeCleanupCursor(Cursor*);
295: void sqliteVdbeSorterReset(Vdbe*);
296: void sqliteVdbeAggReset(Agg*);
297: void sqliteVdbeKeylistFree(Keylist*);
298: void sqliteVdbePopStack(Vdbe*,int);
299: int sqliteVdbeCursorMoveto(Cursor*);
300: int sqliteVdbeByteSwap(int);
301: #if !defined(NDEBUG) || defined(VDBE_PROFILE)
302: void sqliteVdbePrintOp(FILE*, int, Op*);
303: #endif
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