Annotation of embedaddon/php/ext/sqlite/libsqlite/src/vacuum.c, revision 1.1.1.1
1.1 misho 1: /*
2: ** 2003 April 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 file contains code used to implement the VACUUM command.
13: **
14: ** Most of the code in this file may be omitted by defining the
15: ** SQLITE_OMIT_VACUUM macro.
16: **
17: ** $Id: vacuum.c 195361 2005-09-07 15:11:33Z iliaa $
18: */
19: #include "sqliteInt.h"
20: #include "os.h"
21:
22: /*
23: ** A structure for holding a dynamic string - a string that can grow
24: ** without bound.
25: */
26: typedef struct dynStr dynStr;
27: struct dynStr {
28: char *z; /* Text of the string in space obtained from sqliteMalloc() */
29: int nAlloc; /* Amount of space allocated to z[] */
30: int nUsed; /* Next unused slot in z[] */
31: };
32:
33: /*
34: ** A structure that holds the vacuum context
35: */
36: typedef struct vacuumStruct vacuumStruct;
37: struct vacuumStruct {
38: sqlite *dbOld; /* Original database */
39: sqlite *dbNew; /* New database */
40: char **pzErrMsg; /* Write errors here */
41: int rc; /* Set to non-zero on an error */
42: const char *zTable; /* Name of a table being copied */
43: const char *zPragma; /* Pragma to execute with results */
44: dynStr s1, s2; /* Two dynamic strings */
45: };
46:
47: #if !defined(SQLITE_OMIT_VACUUM) || SQLITE_OMIT_VACUUM
48: /*
49: ** Append text to a dynamic string
50: */
51: static void appendText(dynStr *p, const char *zText, int nText){
52: if( nText<0 ) nText = strlen(zText);
53: if( p->z==0 || p->nUsed + nText + 1 >= p->nAlloc ){
54: char *zNew;
55: p->nAlloc = p->nUsed + nText + 1000;
56: zNew = sqliteRealloc(p->z, p->nAlloc);
57: if( zNew==0 ){
58: sqliteFree(p->z);
59: memset(p, 0, sizeof(*p));
60: return;
61: }
62: p->z = zNew;
63: }
64: memcpy(&p->z[p->nUsed], zText, nText+1);
65: p->nUsed += nText;
66: }
67:
68: /*
69: ** Append text to a dynamic string, having first put the text in quotes.
70: */
71: static void appendQuoted(dynStr *p, const char *zText){
72: int i, j;
73: appendText(p, "'", 1);
74: for(i=j=0; zText[i]; i++){
75: if( zText[i]=='\'' ){
76: appendText(p, &zText[j], i-j+1);
77: j = i + 1;
78: appendText(p, "'", 1);
79: }
80: }
81: if( j<i ){
82: appendText(p, &zText[j], i-j);
83: }
84: appendText(p, "'", 1);
85: }
86:
87: /*
88: ** Execute statements of SQL. If an error occurs, write the error
89: ** message into *pzErrMsg and return non-zero.
90: */
91: static int execsql(char **pzErrMsg, sqlite *db, const char *zSql){
92: char *zErrMsg = 0;
93: int rc;
94:
95: /* printf("***** executing *****\n%s\n", zSql); */
96: rc = sqlite_exec(db, zSql, 0, 0, &zErrMsg);
97: if( zErrMsg ){
98: sqliteSetString(pzErrMsg, zErrMsg, (char*)0);
99: sqlite_freemem(zErrMsg);
100: }
101: return rc;
102: }
103:
104: /*
105: ** This is the second stage callback. Each invocation contains all the
106: ** data for a single row of a single table in the original database. This
107: ** routine must write that information into the new database.
108: */
109: static int vacuumCallback2(void *pArg, int argc, char **argv, char **NotUsed){
110: vacuumStruct *p = (vacuumStruct*)pArg;
111: const char *zSep = "(";
112: int i;
113:
114: if( argv==0 ) return 0;
115: p->s2.nUsed = 0;
116: appendText(&p->s2, "INSERT INTO ", -1);
117: appendQuoted(&p->s2, p->zTable);
118: appendText(&p->s2, " VALUES", -1);
119: for(i=0; i<argc; i++){
120: appendText(&p->s2, zSep, 1);
121: zSep = ",";
122: if( argv[i]==0 ){
123: appendText(&p->s2, "NULL", 4);
124: }else{
125: appendQuoted(&p->s2, argv[i]);
126: }
127: }
128: appendText(&p->s2,")", 1);
129: p->rc = execsql(p->pzErrMsg, p->dbNew, p->s2.z);
130: return p->rc;
131: }
132:
133: /*
134: ** This is the first stage callback. Each invocation contains three
135: ** arguments where are taken from the SQLITE_MASTER table of the original
136: ** database: (1) the entry type, (2) the entry name, and (3) the SQL for
137: ** the entry. In all cases, execute the SQL of the third argument.
138: ** For tables, run a query to select all entries in that table and
139: ** transfer them to the second-stage callback.
140: */
141: static int vacuumCallback1(void *pArg, int argc, char **argv, char **NotUsed){
142: vacuumStruct *p = (vacuumStruct*)pArg;
143: int rc = 0;
144: assert( argc==3 );
145: if( argv==0 ) return 0;
146: assert( argv[0]!=0 );
147: assert( argv[1]!=0 );
148: assert( argv[2]!=0 );
149: rc = execsql(p->pzErrMsg, p->dbNew, argv[2]);
150: if( rc==SQLITE_OK && strcmp(argv[0],"table")==0 ){
151: char *zErrMsg = 0;
152: p->s1.nUsed = 0;
153: appendText(&p->s1, "SELECT * FROM ", -1);
154: appendQuoted(&p->s1, argv[1]);
155: p->zTable = argv[1];
156: rc = sqlite_exec(p->dbOld, p->s1.z, vacuumCallback2, p, &zErrMsg);
157: if( zErrMsg ){
158: sqliteSetString(p->pzErrMsg, zErrMsg, (char*)0);
159: sqlite_freemem(zErrMsg);
160: }
161: }
162: if( rc!=SQLITE_ABORT ) p->rc = rc;
163: return rc;
164: }
165:
166: /*
167: ** Generate a random name of 20 character in length.
168: */
169: static void randomName(unsigned char *zBuf){
170: static const unsigned char zChars[] =
171: "abcdefghijklmnopqrstuvwxyz"
172: "0123456789";
173: int i;
174: sqliteRandomness(20, zBuf);
175: for(i=0; i<20; i++){
176: zBuf[i] = zChars[ zBuf[i]%(sizeof(zChars)-1) ];
177: }
178: }
179: #endif
180:
181: /*
182: ** The non-standard VACUUM command is used to clean up the database,
183: ** collapse free space, etc. It is modelled after the VACUUM command
184: ** in PostgreSQL.
185: **
186: ** In version 1.0.x of SQLite, the VACUUM command would call
187: ** gdbm_reorganize() on all the database tables. But beginning
188: ** with 2.0.0, SQLite no longer uses GDBM so this command has
189: ** become a no-op.
190: */
191: void sqliteVacuum(Parse *pParse, Token *pTableName){
192: Vdbe *v = sqliteGetVdbe(pParse);
193: sqliteVdbeAddOp(v, OP_Vacuum, 0, 0);
194: return;
195: }
196:
197: /*
198: ** This routine implements the OP_Vacuum opcode of the VDBE.
199: */
200: int sqliteRunVacuum(char **pzErrMsg, sqlite *db){
201: #if !defined(SQLITE_OMIT_VACUUM) || SQLITE_OMIT_VACUUM
202: const char *zFilename; /* full pathname of the database file */
203: int nFilename; /* number of characters in zFilename[] */
204: char *zTemp = 0; /* a temporary file in same directory as zFilename */
205: sqlite *dbNew = 0; /* The new vacuumed database */
206: int rc = SQLITE_OK; /* Return code from service routines */
207: int i; /* Loop counter */
208: char *zErrMsg; /* Error message */
209: vacuumStruct sVac; /* Information passed to callbacks */
210:
211: if( db->flags & SQLITE_InTrans ){
212: sqliteSetString(pzErrMsg, "cannot VACUUM from within a transaction",
213: (char*)0);
214: return SQLITE_ERROR;
215: }
216: if( db->flags & SQLITE_Interrupt ){
217: return SQLITE_INTERRUPT;
218: }
219: memset(&sVac, 0, sizeof(sVac));
220:
221: /* Get the full pathname of the database file and create two
222: ** temporary filenames in the same directory as the original file.
223: */
224: zFilename = sqliteBtreeGetFilename(db->aDb[0].pBt);
225: if( zFilename==0 ){
226: /* This only happens with the in-memory database. VACUUM is a no-op
227: ** there, so just return */
228: return SQLITE_OK;
229: }
230: nFilename = strlen(zFilename);
231: zTemp = sqliteMalloc( nFilename+100 );
232: if( zTemp==0 ) return SQLITE_NOMEM;
233: strcpy(zTemp, zFilename);
234: for(i=0; i<10; i++){
235: zTemp[nFilename] = '-';
236: randomName((unsigned char*)&zTemp[nFilename+1]);
237: if( !sqliteOsFileExists(zTemp) ) break;
238: }
239: if( i>=10 ){
240: sqliteSetString(pzErrMsg, "unable to create a temporary database file "
241: "in the same directory as the original database", (char*)0);
242: goto end_of_vacuum;
243: }
244:
245:
246: dbNew = sqlite_open(zTemp, 0, &zErrMsg);
247: if( dbNew==0 ){
248: sqliteSetString(pzErrMsg, "unable to open a temporary database at ",
249: zTemp, " - ", zErrMsg, (char*)0);
250: goto end_of_vacuum;
251: }
252: if( (rc = execsql(pzErrMsg, db, "BEGIN"))!=0 ) goto end_of_vacuum;
253: if( (rc = execsql(pzErrMsg, dbNew, "PRAGMA synchronous=off; BEGIN"))!=0 ){
254: goto end_of_vacuum;
255: }
256:
257: sVac.dbOld = db;
258: sVac.dbNew = dbNew;
259: sVac.pzErrMsg = pzErrMsg;
260: if( rc==SQLITE_OK ){
261: rc = sqlite_exec(db,
262: "SELECT type, name, sql FROM sqlite_master "
263: "WHERE sql NOT NULL AND type!='view' "
264: "UNION ALL "
265: "SELECT type, name, sql FROM sqlite_master "
266: "WHERE sql NOT NULL AND type=='view'",
267: vacuumCallback1, &sVac, &zErrMsg);
268: }
269: if( rc==SQLITE_OK ){
270: int meta1[SQLITE_N_BTREE_META];
271: int meta2[SQLITE_N_BTREE_META];
272: sqliteBtreeGetMeta(db->aDb[0].pBt, meta1);
273: sqliteBtreeGetMeta(dbNew->aDb[0].pBt, meta2);
274: meta2[1] = meta1[1]+1;
275: meta2[3] = meta1[3];
276: meta2[4] = meta1[4];
277: meta2[6] = meta1[6];
278: rc = sqliteBtreeUpdateMeta(dbNew->aDb[0].pBt, meta2);
279: }
280: if( rc==SQLITE_OK ){
281: rc = sqliteBtreeCopyFile(db->aDb[0].pBt, dbNew->aDb[0].pBt);
282: sqlite_exec(db, "COMMIT", 0, 0, 0);
283: sqliteResetInternalSchema(db, 0);
284: }
285:
286: end_of_vacuum:
287: if( rc && zErrMsg!=0 ){
288: sqliteSetString(pzErrMsg, "unable to vacuum database - ",
289: zErrMsg, (char*)0);
290: }
291: sqlite_exec(db, "ROLLBACK", 0, 0, 0);
292: if( (dbNew && (dbNew->flags & SQLITE_Interrupt))
293: || (db->flags & SQLITE_Interrupt) ){
294: rc = SQLITE_INTERRUPT;
295: }
296: if( dbNew ) sqlite_close(dbNew);
297: sqliteOsDelete(zTemp);
298: sqliteFree(zTemp);
299: sqliteFree(sVac.s1.z);
300: sqliteFree(sVac.s2.z);
301: if( zErrMsg ) sqlite_freemem(zErrMsg);
302: if( rc==SQLITE_ABORT && sVac.rc!=SQLITE_INTERRUPT ) sVac.rc = SQLITE_ERROR;
303: return sVac.rc;
304: #endif
305: }
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