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| 1 /* | |
| 2 ** 2006 June 10 | |
| 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 help implement virtual tables. | |
| 13 ** | |
| 14 ** $Id: vtab.c,v 1.94 2009/08/08 18:01:08 drh Exp $ | |
| 15 */ | |
| 16 #ifndef SQLITE_OMIT_VIRTUALTABLE | |
| 17 #include "sqliteInt.h" | |
| 18 | |
| 19 /* | |
| 20 ** The actual function that does the work of creating a new module. | |
| 21 ** This function implements the sqlite3_create_module() and | |
| 22 ** sqlite3_create_module_v2() interfaces. | |
| 23 */ | |
| 24 static int createModule( | |
| 25 sqlite3 *db, /* Database in which module is registered */ | |
| 26 const char *zName, /* Name assigned to this module */ | |
| 27 const sqlite3_module *pModule, /* The definition of the module */ | |
| 28 void *pAux, /* Context pointer for xCreate/xConnect */ | |
| 29 void (*xDestroy)(void *) /* Module destructor function */ | |
| 30 ){ | |
| 31 int rc, nName; | |
| 32 Module *pMod; | |
| 33 | |
| 34 sqlite3_mutex_enter(db->mutex); | |
| 35 nName = sqlite3Strlen30(zName); | |
| 36 pMod = (Module *)sqlite3DbMallocRaw(db, sizeof(Module) + nName + 1); | |
| 37 if( pMod ){ | |
| 38 Module *pDel; | |
| 39 char *zCopy = (char *)(&pMod[1]); | |
| 40 memcpy(zCopy, zName, nName+1); | |
| 41 pMod->zName = zCopy; | |
| 42 pMod->pModule = pModule; | |
| 43 pMod->pAux = pAux; | |
| 44 pMod->xDestroy = xDestroy; | |
| 45 pDel = (Module *)sqlite3HashInsert(&db->aModule, zCopy, nName, (void*)pMod); | |
| 46 if( pDel && pDel->xDestroy ){ | |
| 47 pDel->xDestroy(pDel->pAux); | |
| 48 } | |
| 49 sqlite3DbFree(db, pDel); | |
| 50 if( pDel==pMod ){ | |
| 51 db->mallocFailed = 1; | |
| 52 } | |
| 53 sqlite3ResetInternalSchema(db, 0); | |
| 54 }else if( xDestroy ){ | |
| 55 xDestroy(pAux); | |
| 56 } | |
| 57 rc = sqlite3ApiExit(db, SQLITE_OK); | |
| 58 sqlite3_mutex_leave(db->mutex); | |
| 59 return rc; | |
| 60 } | |
| 61 | |
| 62 | |
| 63 /* | |
| 64 ** External API function used to create a new virtual-table module. | |
| 65 */ | |
| 66 int sqlite3_create_module( | |
| 67 sqlite3 *db, /* Database in which module is registered */ | |
| 68 const char *zName, /* Name assigned to this module */ | |
| 69 const sqlite3_module *pModule, /* The definition of the module */ | |
| 70 void *pAux /* Context pointer for xCreate/xConnect */ | |
| 71 ){ | |
| 72 return createModule(db, zName, pModule, pAux, 0); | |
| 73 } | |
| 74 | |
| 75 /* | |
| 76 ** External API function used to create a new virtual-table module. | |
| 77 */ | |
| 78 int sqlite3_create_module_v2( | |
| 79 sqlite3 *db, /* Database in which module is registered */ | |
| 80 const char *zName, /* Name assigned to this module */ | |
| 81 const sqlite3_module *pModule, /* The definition of the module */ | |
| 82 void *pAux, /* Context pointer for xCreate/xConnect */ | |
| 83 void (*xDestroy)(void *) /* Module destructor function */ | |
| 84 ){ | |
| 85 return createModule(db, zName, pModule, pAux, xDestroy); | |
| 86 } | |
| 87 | |
| 88 /* | |
| 89 ** Lock the virtual table so that it cannot be disconnected. | |
| 90 ** Locks nest. Every lock should have a corresponding unlock. | |
| 91 ** If an unlock is omitted, resources leaks will occur. | |
| 92 ** | |
| 93 ** If a disconnect is attempted while a virtual table is locked, | |
| 94 ** the disconnect is deferred until all locks have been removed. | |
| 95 */ | |
| 96 void sqlite3VtabLock(VTable *pVTab){ | |
| 97 pVTab->nRef++; | |
| 98 } | |
| 99 | |
| 100 | |
| 101 /* | |
| 102 ** pTab is a pointer to a Table structure representing a virtual-table. | |
| 103 ** Return a pointer to the VTable object used by connection db to access | |
| 104 ** this virtual-table, if one has been created, or NULL otherwise. | |
| 105 */ | |
| 106 VTable *sqlite3GetVTable(sqlite3 *db, Table *pTab){ | |
| 107 VTable *pVtab; | |
| 108 assert( IsVirtual(pTab) ); | |
| 109 for(pVtab=pTab->pVTable; pVtab && pVtab->db!=db; pVtab=pVtab->pNext); | |
| 110 return pVtab; | |
| 111 } | |
| 112 | |
| 113 /* | |
| 114 ** Decrement the ref-count on a virtual table object. When the ref-count | |
| 115 ** reaches zero, call the xDisconnect() method to delete the object. | |
| 116 */ | |
| 117 void sqlite3VtabUnlock(VTable *pVTab){ | |
| 118 sqlite3 *db = pVTab->db; | |
| 119 | |
| 120 assert( db ); | |
| 121 assert( pVTab->nRef>0 ); | |
| 122 assert( sqlite3SafetyCheckOk(db) ); | |
| 123 | |
| 124 pVTab->nRef--; | |
| 125 if( pVTab->nRef==0 ){ | |
| 126 sqlite3_vtab *p = pVTab->pVtab; | |
| 127 if( p ){ | |
| 128 #ifdef SQLITE_DEBUG | |
| 129 if( pVTab->db->magic==SQLITE_MAGIC_BUSY ){ | |
| 130 (void)sqlite3SafetyOff(db); | |
| 131 p->pModule->xDisconnect(p); | |
| 132 (void)sqlite3SafetyOn(db); | |
| 133 } else | |
| 134 #endif | |
| 135 { | |
| 136 p->pModule->xDisconnect(p); | |
| 137 } | |
| 138 } | |
| 139 sqlite3DbFree(db, pVTab); | |
| 140 } | |
| 141 } | |
| 142 | |
| 143 /* | |
| 144 ** Table p is a virtual table. This function moves all elements in the | |
| 145 ** p->pVTable list to the sqlite3.pDisconnect lists of their associated | |
| 146 ** database connections to be disconnected at the next opportunity. | |
| 147 ** Except, if argument db is not NULL, then the entry associated with | |
| 148 ** connection db is left in the p->pVTable list. | |
| 149 */ | |
| 150 static VTable *vtabDisconnectAll(sqlite3 *db, Table *p){ | |
| 151 VTable *pRet = 0; | |
| 152 VTable *pVTable = p->pVTable; | |
| 153 p->pVTable = 0; | |
| 154 | |
| 155 /* Assert that the mutex (if any) associated with the BtShared database | |
| 156 ** that contains table p is held by the caller. See header comments | |
| 157 ** above function sqlite3VtabUnlockList() for an explanation of why | |
| 158 ** this makes it safe to access the sqlite3.pDisconnect list of any | |
| 159 ** database connection that may have an entry in the p->pVTable list. */ | |
| 160 assert( db==0 || | |
| 161 sqlite3BtreeHoldsMutex(db->aDb[sqlite3SchemaToIndex(db, p->pSchema)].pBt) | |
| 162 ); | |
| 163 | |
| 164 while( pVTable ){ | |
| 165 sqlite3 *db2 = pVTable->db; | |
| 166 VTable *pNext = pVTable->pNext; | |
| 167 assert( db2 ); | |
| 168 if( db2==db ){ | |
| 169 pRet = pVTable; | |
| 170 p->pVTable = pRet; | |
| 171 pRet->pNext = 0; | |
| 172 }else{ | |
| 173 pVTable->pNext = db2->pDisconnect; | |
| 174 db2->pDisconnect = pVTable; | |
| 175 } | |
| 176 pVTable = pNext; | |
| 177 } | |
| 178 | |
| 179 assert( !db || pRet ); | |
| 180 return pRet; | |
| 181 } | |
| 182 | |
| 183 | |
| 184 /* | |
| 185 ** Disconnect all the virtual table objects in the sqlite3.pDisconnect list. | |
| 186 ** | |
| 187 ** This function may only be called when the mutexes associated with all | |
| 188 ** shared b-tree databases opened using connection db are held by the | |
| 189 ** caller. This is done to protect the sqlite3.pDisconnect list. The | |
| 190 ** sqlite3.pDisconnect list is accessed only as follows: | |
| 191 ** | |
| 192 ** 1) By this function. In this case, all BtShared mutexes and the mutex | |
| 193 ** associated with the database handle itself must be held. | |
| 194 ** | |
| 195 ** 2) By function vtabDisconnectAll(), when it adds a VTable entry to | |
| 196 ** the sqlite3.pDisconnect list. In this case either the BtShared mutex | |
| 197 ** associated with the database the virtual table is stored in is held | |
| 198 ** or, if the virtual table is stored in a non-sharable database, then | |
| 199 ** the database handle mutex is held. | |
| 200 ** | |
| 201 ** As a result, a sqlite3.pDisconnect cannot be accessed simultaneously | |
| 202 ** by multiple threads. It is thread-safe. | |
| 203 */ | |
| 204 void sqlite3VtabUnlockList(sqlite3 *db){ | |
| 205 VTable *p = db->pDisconnect; | |
| 206 db->pDisconnect = 0; | |
| 207 | |
| 208 assert( sqlite3BtreeHoldsAllMutexes(db) ); | |
| 209 assert( sqlite3_mutex_held(db->mutex) ); | |
| 210 | |
| 211 if( p ){ | |
| 212 sqlite3ExpirePreparedStatements(db); | |
| 213 do { | |
| 214 VTable *pNext = p->pNext; | |
| 215 sqlite3VtabUnlock(p); | |
| 216 p = pNext; | |
| 217 }while( p ); | |
| 218 } | |
| 219 } | |
| 220 | |
| 221 /* | |
| 222 ** Clear any and all virtual-table information from the Table record. | |
| 223 ** This routine is called, for example, just before deleting the Table | |
| 224 ** record. | |
| 225 ** | |
| 226 ** Since it is a virtual-table, the Table structure contains a pointer | |
| 227 ** to the head of a linked list of VTable structures. Each VTable | |
| 228 ** structure is associated with a single sqlite3* user of the schema. | |
| 229 ** The reference count of the VTable structure associated with database | |
| 230 ** connection db is decremented immediately (which may lead to the | |
| 231 ** structure being xDisconnected and free). Any other VTable structures | |
| 232 ** in the list are moved to the sqlite3.pDisconnect list of the associated | |
| 233 ** database connection. | |
| 234 */ | |
| 235 void sqlite3VtabClear(Table *p){ | |
| 236 vtabDisconnectAll(0, p); | |
| 237 if( p->azModuleArg ){ | |
| 238 int i; | |
| 239 for(i=0; i<p->nModuleArg; i++){ | |
| 240 sqlite3DbFree(p->dbMem, p->azModuleArg[i]); | |
| 241 } | |
| 242 sqlite3DbFree(p->dbMem, p->azModuleArg); | |
| 243 } | |
| 244 } | |
| 245 | |
| 246 /* | |
| 247 ** Add a new module argument to pTable->azModuleArg[]. | |
| 248 ** The string is not copied - the pointer is stored. The | |
| 249 ** string will be freed automatically when the table is | |
| 250 ** deleted. | |
| 251 */ | |
| 252 static void addModuleArgument(sqlite3 *db, Table *pTable, char *zArg){ | |
| 253 int i = pTable->nModuleArg++; | |
| 254 int nBytes = sizeof(char *)*(1+pTable->nModuleArg); | |
| 255 char **azModuleArg; | |
| 256 azModuleArg = sqlite3DbRealloc(db, pTable->azModuleArg, nBytes); | |
| 257 if( azModuleArg==0 ){ | |
| 258 int j; | |
| 259 for(j=0; j<i; j++){ | |
| 260 sqlite3DbFree(db, pTable->azModuleArg[j]); | |
| 261 } | |
| 262 sqlite3DbFree(db, zArg); | |
| 263 sqlite3DbFree(db, pTable->azModuleArg); | |
| 264 pTable->nModuleArg = 0; | |
| 265 }else{ | |
| 266 azModuleArg[i] = zArg; | |
| 267 azModuleArg[i+1] = 0; | |
| 268 } | |
| 269 pTable->azModuleArg = azModuleArg; | |
| 270 } | |
| 271 | |
| 272 /* | |
| 273 ** The parser calls this routine when it first sees a CREATE VIRTUAL TABLE | |
| 274 ** statement. The module name has been parsed, but the optional list | |
| 275 ** of parameters that follow the module name are still pending. | |
| 276 */ | |
| 277 void sqlite3VtabBeginParse( | |
| 278 Parse *pParse, /* Parsing context */ | |
| 279 Token *pName1, /* Name of new table, or database name */ | |
| 280 Token *pName2, /* Name of new table or NULL */ | |
| 281 Token *pModuleName /* Name of the module for the virtual table */ | |
| 282 ){ | |
| 283 int iDb; /* The database the table is being created in */ | |
| 284 Table *pTable; /* The new virtual table */ | |
| 285 sqlite3 *db; /* Database connection */ | |
| 286 | |
| 287 sqlite3StartTable(pParse, pName1, pName2, 0, 0, 1, 0); | |
| 288 pTable = pParse->pNewTable; | |
| 289 if( pTable==0 ) return; | |
| 290 assert( 0==pTable->pIndex ); | |
| 291 | |
| 292 db = pParse->db; | |
| 293 iDb = sqlite3SchemaToIndex(db, pTable->pSchema); | |
| 294 assert( iDb>=0 ); | |
| 295 | |
| 296 pTable->tabFlags |= TF_Virtual; | |
| 297 pTable->nModuleArg = 0; | |
| 298 addModuleArgument(db, pTable, sqlite3NameFromToken(db, pModuleName)); | |
| 299 addModuleArgument(db, pTable, sqlite3DbStrDup(db, db->aDb[iDb].zName)); | |
| 300 addModuleArgument(db, pTable, sqlite3DbStrDup(db, pTable->zName)); | |
| 301 pParse->sNameToken.n = (int)(&pModuleName->z[pModuleName->n] - pName1->z); | |
| 302 | |
| 303 #ifndef SQLITE_OMIT_AUTHORIZATION | |
| 304 /* Creating a virtual table invokes the authorization callback twice. | |
| 305 ** The first invocation, to obtain permission to INSERT a row into the | |
| 306 ** sqlite_master table, has already been made by sqlite3StartTable(). | |
| 307 ** The second call, to obtain permission to create the table, is made now. | |
| 308 */ | |
| 309 if( pTable->azModuleArg ){ | |
| 310 sqlite3AuthCheck(pParse, SQLITE_CREATE_VTABLE, pTable->zName, | |
| 311 pTable->azModuleArg[0], pParse->db->aDb[iDb].zName); | |
| 312 } | |
| 313 #endif | |
| 314 } | |
| 315 | |
| 316 /* | |
| 317 ** This routine takes the module argument that has been accumulating | |
| 318 ** in pParse->zArg[] and appends it to the list of arguments on the | |
| 319 ** virtual table currently under construction in pParse->pTable. | |
| 320 */ | |
| 321 static void addArgumentToVtab(Parse *pParse){ | |
| 322 if( pParse->sArg.z && ALWAYS(pParse->pNewTable) ){ | |
| 323 const char *z = (const char*)pParse->sArg.z; | |
| 324 int n = pParse->sArg.n; | |
| 325 sqlite3 *db = pParse->db; | |
| 326 addModuleArgument(db, pParse->pNewTable, sqlite3DbStrNDup(db, z, n)); | |
| 327 } | |
| 328 } | |
| 329 | |
| 330 /* | |
| 331 ** The parser calls this routine after the CREATE VIRTUAL TABLE statement | |
| 332 ** has been completely parsed. | |
| 333 */ | |
| 334 void sqlite3VtabFinishParse(Parse *pParse, Token *pEnd){ | |
| 335 Table *pTab = pParse->pNewTable; /* The table being constructed */ | |
| 336 sqlite3 *db = pParse->db; /* The database connection */ | |
| 337 | |
| 338 if( pTab==0 ) return; | |
| 339 addArgumentToVtab(pParse); | |
| 340 pParse->sArg.z = 0; | |
| 341 if( pTab->nModuleArg<1 ) return; | |
| 342 | |
| 343 /* If the CREATE VIRTUAL TABLE statement is being entered for the | |
| 344 ** first time (in other words if the virtual table is actually being | |
| 345 ** created now instead of just being read out of sqlite_master) then | |
| 346 ** do additional initialization work and store the statement text | |
| 347 ** in the sqlite_master table. | |
| 348 */ | |
| 349 if( !db->init.busy ){ | |
| 350 char *zStmt; | |
| 351 char *zWhere; | |
| 352 int iDb; | |
| 353 Vdbe *v; | |
| 354 | |
| 355 /* Compute the complete text of the CREATE VIRTUAL TABLE statement */ | |
| 356 if( pEnd ){ | |
| 357 pParse->sNameToken.n = (int)(pEnd->z - pParse->sNameToken.z) + pEnd->n; | |
| 358 } | |
| 359 zStmt = sqlite3MPrintf(db, "CREATE VIRTUAL TABLE %T", &pParse->sNameToken); | |
| 360 | |
| 361 /* A slot for the record has already been allocated in the | |
| 362 ** SQLITE_MASTER table. We just need to update that slot with all | |
| 363 ** the information we've collected. | |
| 364 ** | |
| 365 ** The VM register number pParse->regRowid holds the rowid of an | |
| 366 ** entry in the sqlite_master table tht was created for this vtab | |
| 367 ** by sqlite3StartTable(). | |
| 368 */ | |
| 369 iDb = sqlite3SchemaToIndex(db, pTab->pSchema); | |
| 370 sqlite3NestedParse(pParse, | |
| 371 "UPDATE %Q.%s " | |
| 372 "SET type='table', name=%Q, tbl_name=%Q, rootpage=0, sql=%Q " | |
| 373 "WHERE rowid=#%d", | |
| 374 db->aDb[iDb].zName, SCHEMA_TABLE(iDb), | |
| 375 pTab->zName, | |
| 376 pTab->zName, | |
| 377 zStmt, | |
| 378 pParse->regRowid | |
| 379 ); | |
| 380 sqlite3DbFree(db, zStmt); | |
| 381 v = sqlite3GetVdbe(pParse); | |
| 382 sqlite3ChangeCookie(pParse, iDb); | |
| 383 | |
| 384 sqlite3VdbeAddOp2(v, OP_Expire, 0, 0); | |
| 385 zWhere = sqlite3MPrintf(db, "name='%q'", pTab->zName); | |
| 386 sqlite3VdbeAddOp4(v, OP_ParseSchema, iDb, 1, 0, zWhere, P4_DYNAMIC); | |
| 387 sqlite3VdbeAddOp4(v, OP_VCreate, iDb, 0, 0, | |
| 388 pTab->zName, sqlite3Strlen30(pTab->zName) + 1); | |
| 389 } | |
| 390 | |
| 391 /* If we are rereading the sqlite_master table create the in-memory | |
| 392 ** record of the table. The xConnect() method is not called until | |
| 393 ** the first time the virtual table is used in an SQL statement. This | |
| 394 ** allows a schema that contains virtual tables to be loaded before | |
| 395 ** the required virtual table implementations are registered. */ | |
| 396 else { | |
| 397 Table *pOld; | |
| 398 Schema *pSchema = pTab->pSchema; | |
| 399 const char *zName = pTab->zName; | |
| 400 int nName = sqlite3Strlen30(zName); | |
| 401 pOld = sqlite3HashInsert(&pSchema->tblHash, zName, nName, pTab); | |
| 402 if( pOld ){ | |
| 403 db->mallocFailed = 1; | |
| 404 assert( pTab==pOld ); /* Malloc must have failed inside HashInsert() */ | |
| 405 return; | |
| 406 } | |
| 407 pSchema->db = pParse->db; | |
| 408 pParse->pNewTable = 0; | |
| 409 } | |
| 410 } | |
| 411 | |
| 412 /* | |
| 413 ** The parser calls this routine when it sees the first token | |
| 414 ** of an argument to the module name in a CREATE VIRTUAL TABLE statement. | |
| 415 */ | |
| 416 void sqlite3VtabArgInit(Parse *pParse){ | |
| 417 addArgumentToVtab(pParse); | |
| 418 pParse->sArg.z = 0; | |
| 419 pParse->sArg.n = 0; | |
| 420 } | |
| 421 | |
| 422 /* | |
| 423 ** The parser calls this routine for each token after the first token | |
| 424 ** in an argument to the module name in a CREATE VIRTUAL TABLE statement. | |
| 425 */ | |
| 426 void sqlite3VtabArgExtend(Parse *pParse, Token *p){ | |
| 427 Token *pArg = &pParse->sArg; | |
| 428 if( pArg->z==0 ){ | |
| 429 pArg->z = p->z; | |
| 430 pArg->n = p->n; | |
| 431 }else{ | |
| 432 assert(pArg->z < p->z); | |
| 433 pArg->n = (int)(&p->z[p->n] - pArg->z); | |
| 434 } | |
| 435 } | |
| 436 | |
| 437 /* | |
| 438 ** Invoke a virtual table constructor (either xCreate or xConnect). The | |
| 439 ** pointer to the function to invoke is passed as the fourth parameter | |
| 440 ** to this procedure. | |
| 441 */ | |
| 442 static int vtabCallConstructor( | |
| 443 sqlite3 *db, | |
| 444 Table *pTab, | |
| 445 Module *pMod, | |
| 446 int (*xConstruct)(sqlite3*,void*,int,const char*const*,sqlite3_vtab**,char**), | |
| 447 char **pzErr | |
| 448 ){ | |
| 449 VTable *pVTable; | |
| 450 int rc; | |
| 451 const char *const*azArg = (const char *const*)pTab->azModuleArg; | |
| 452 int nArg = pTab->nModuleArg; | |
| 453 char *zErr = 0; | |
| 454 char *zModuleName = sqlite3MPrintf(db, "%s", pTab->zName); | |
| 455 | |
| 456 if( !zModuleName ){ | |
| 457 return SQLITE_NOMEM; | |
| 458 } | |
| 459 | |
| 460 pVTable = sqlite3DbMallocZero(db, sizeof(VTable)); | |
| 461 if( !pVTable ){ | |
| 462 sqlite3DbFree(db, zModuleName); | |
| 463 return SQLITE_NOMEM; | |
| 464 } | |
| 465 pVTable->db = db; | |
| 466 pVTable->pMod = pMod; | |
| 467 | |
| 468 assert( !db->pVTab ); | |
| 469 assert( xConstruct ); | |
| 470 db->pVTab = pTab; | |
| 471 | |
| 472 /* Invoke the virtual table constructor */ | |
| 473 (void)sqlite3SafetyOff(db); | |
| 474 rc = xConstruct(db, pMod->pAux, nArg, azArg, &pVTable->pVtab, &zErr); | |
| 475 (void)sqlite3SafetyOn(db); | |
| 476 if( rc==SQLITE_NOMEM ) db->mallocFailed = 1; | |
| 477 | |
| 478 if( SQLITE_OK!=rc ){ | |
| 479 if( zErr==0 ){ | |
| 480 *pzErr = sqlite3MPrintf(db, "vtable constructor failed: %s", zModuleName); | |
| 481 }else { | |
| 482 *pzErr = sqlite3MPrintf(db, "%s", zErr); | |
| 483 sqlite3DbFree(db, zErr); | |
| 484 } | |
| 485 sqlite3DbFree(db, pVTable); | |
| 486 }else if( ALWAYS(pVTable->pVtab) ){ | |
| 487 /* Justification of ALWAYS(): A correct vtab constructor must allocate | |
| 488 ** the sqlite3_vtab object if successful. */ | |
| 489 pVTable->pVtab->pModule = pMod->pModule; | |
| 490 pVTable->nRef = 1; | |
| 491 if( db->pVTab ){ | |
| 492 const char *zFormat = "vtable constructor did not declare schema: %s"; | |
| 493 *pzErr = sqlite3MPrintf(db, zFormat, pTab->zName); | |
| 494 sqlite3VtabUnlock(pVTable); | |
| 495 rc = SQLITE_ERROR; | |
| 496 }else{ | |
| 497 int iCol; | |
| 498 /* If everything went according to plan, link the new VTable structure | |
| 499 ** into the linked list headed by pTab->pVTable. Then loop through the | |
| 500 ** columns of the table to see if any of them contain the token "hidden". | |
| 501 ** If so, set the Column.isHidden flag and remove the token from | |
| 502 ** the type string. */ | |
| 503 pVTable->pNext = pTab->pVTable; | |
| 504 pTab->pVTable = pVTable; | |
| 505 | |
| 506 for(iCol=0; iCol<pTab->nCol; iCol++){ | |
| 507 char *zType = pTab->aCol[iCol].zType; | |
| 508 int nType; | |
| 509 int i = 0; | |
| 510 if( !zType ) continue; | |
| 511 nType = sqlite3Strlen30(zType); | |
| 512 if( sqlite3StrNICmp("hidden", zType, 6)||(zType[6] && zType[6]!=' ') ){ | |
| 513 for(i=0; i<nType; i++){ | |
| 514 if( (0==sqlite3StrNICmp(" hidden", &zType[i], 7)) | |
| 515 && (zType[i+7]=='\0' || zType[i+7]==' ') | |
| 516 ){ | |
| 517 i++; | |
| 518 break; | |
| 519 } | |
| 520 } | |
| 521 } | |
| 522 if( i<nType ){ | |
| 523 int j; | |
| 524 int nDel = 6 + (zType[i+6] ? 1 : 0); | |
| 525 for(j=i; (j+nDel)<=nType; j++){ | |
| 526 zType[j] = zType[j+nDel]; | |
| 527 } | |
| 528 if( zType[i]=='\0' && i>0 ){ | |
| 529 assert(zType[i-1]==' '); | |
| 530 zType[i-1] = '\0'; | |
| 531 } | |
| 532 pTab->aCol[iCol].isHidden = 1; | |
| 533 } | |
| 534 } | |
| 535 } | |
| 536 } | |
| 537 | |
| 538 sqlite3DbFree(db, zModuleName); | |
| 539 db->pVTab = 0; | |
| 540 return rc; | |
| 541 } | |
| 542 | |
| 543 /* | |
| 544 ** This function is invoked by the parser to call the xConnect() method | |
| 545 ** of the virtual table pTab. If an error occurs, an error code is returned | |
| 546 ** and an error left in pParse. | |
| 547 ** | |
| 548 ** This call is a no-op if table pTab is not a virtual table. | |
| 549 */ | |
| 550 int sqlite3VtabCallConnect(Parse *pParse, Table *pTab){ | |
| 551 sqlite3 *db = pParse->db; | |
| 552 const char *zMod; | |
| 553 Module *pMod; | |
| 554 int rc; | |
| 555 | |
| 556 assert( pTab ); | |
| 557 if( (pTab->tabFlags & TF_Virtual)==0 || sqlite3GetVTable(db, pTab) ){ | |
| 558 return SQLITE_OK; | |
| 559 } | |
| 560 | |
| 561 /* Locate the required virtual table module */ | |
| 562 zMod = pTab->azModuleArg[0]; | |
| 563 pMod = (Module*)sqlite3HashFind(&db->aModule, zMod, sqlite3Strlen30(zMod)); | |
| 564 | |
| 565 if( !pMod ){ | |
| 566 const char *zModule = pTab->azModuleArg[0]; | |
| 567 sqlite3ErrorMsg(pParse, "no such module: %s", zModule); | |
| 568 rc = SQLITE_ERROR; | |
| 569 }else{ | |
| 570 char *zErr = 0; | |
| 571 rc = vtabCallConstructor(db, pTab, pMod, pMod->pModule->xConnect, &zErr); | |
| 572 if( rc!=SQLITE_OK ){ | |
| 573 sqlite3ErrorMsg(pParse, "%s", zErr); | |
| 574 } | |
| 575 sqlite3DbFree(db, zErr); | |
| 576 } | |
| 577 | |
| 578 return rc; | |
| 579 } | |
| 580 | |
| 581 /* | |
| 582 ** Add the virtual table pVTab to the array sqlite3.aVTrans[]. | |
| 583 */ | |
| 584 static int addToVTrans(sqlite3 *db, VTable *pVTab){ | |
| 585 const int ARRAY_INCR = 5; | |
| 586 | |
| 587 /* Grow the sqlite3.aVTrans array if required */ | |
| 588 if( (db->nVTrans%ARRAY_INCR)==0 ){ | |
| 589 VTable **aVTrans; | |
| 590 int nBytes = sizeof(sqlite3_vtab *) * (db->nVTrans + ARRAY_INCR); | |
| 591 aVTrans = sqlite3DbRealloc(db, (void *)db->aVTrans, nBytes); | |
| 592 if( !aVTrans ){ | |
| 593 return SQLITE_NOMEM; | |
| 594 } | |
| 595 memset(&aVTrans[db->nVTrans], 0, sizeof(sqlite3_vtab *)*ARRAY_INCR); | |
| 596 db->aVTrans = aVTrans; | |
| 597 } | |
| 598 | |
| 599 /* Add pVtab to the end of sqlite3.aVTrans */ | |
| 600 db->aVTrans[db->nVTrans++] = pVTab; | |
| 601 sqlite3VtabLock(pVTab); | |
| 602 return SQLITE_OK; | |
| 603 } | |
| 604 | |
| 605 /* | |
| 606 ** This function is invoked by the vdbe to call the xCreate method | |
| 607 ** of the virtual table named zTab in database iDb. | |
| 608 ** | |
| 609 ** If an error occurs, *pzErr is set to point an an English language | |
| 610 ** description of the error and an SQLITE_XXX error code is returned. | |
| 611 ** In this case the caller must call sqlite3DbFree(db, ) on *pzErr. | |
| 612 */ | |
| 613 int sqlite3VtabCallCreate(sqlite3 *db, int iDb, const char *zTab, char **pzErr){ | |
| 614 int rc = SQLITE_OK; | |
| 615 Table *pTab; | |
| 616 Module *pMod; | |
| 617 const char *zMod; | |
| 618 | |
| 619 pTab = sqlite3FindTable(db, zTab, db->aDb[iDb].zName); | |
| 620 assert( pTab && (pTab->tabFlags & TF_Virtual)!=0 && !pTab->pVTable ); | |
| 621 | |
| 622 /* Locate the required virtual table module */ | |
| 623 zMod = pTab->azModuleArg[0]; | |
| 624 pMod = (Module*)sqlite3HashFind(&db->aModule, zMod, sqlite3Strlen30(zMod)); | |
| 625 | |
| 626 /* If the module has been registered and includes a Create method, | |
| 627 ** invoke it now. If the module has not been registered, return an | |
| 628 ** error. Otherwise, do nothing. | |
| 629 */ | |
| 630 if( !pMod ){ | |
| 631 *pzErr = sqlite3MPrintf(db, "no such module: %s", zMod); | |
| 632 rc = SQLITE_ERROR; | |
| 633 }else{ | |
| 634 rc = vtabCallConstructor(db, pTab, pMod, pMod->pModule->xCreate, pzErr); | |
| 635 } | |
| 636 | |
| 637 /* Justification of ALWAYS(): The xConstructor method is required to | |
| 638 ** create a valid sqlite3_vtab if it returns SQLITE_OK. */ | |
| 639 if( rc==SQLITE_OK && ALWAYS(sqlite3GetVTable(db, pTab)) ){ | |
| 640 rc = addToVTrans(db, sqlite3GetVTable(db, pTab)); | |
| 641 } | |
| 642 | |
| 643 return rc; | |
| 644 } | |
| 645 | |
| 646 /* | |
| 647 ** This function is used to set the schema of a virtual table. It is only | |
| 648 ** valid to call this function from within the xCreate() or xConnect() of a | |
| 649 ** virtual table module. | |
| 650 */ | |
| 651 int sqlite3_declare_vtab(sqlite3 *db, const char *zCreateTable){ | |
| 652 Parse *pParse; | |
| 653 | |
| 654 int rc = SQLITE_OK; | |
| 655 Table *pTab; | |
| 656 char *zErr = 0; | |
| 657 | |
| 658 sqlite3_mutex_enter(db->mutex); | |
| 659 pTab = db->pVTab; | |
| 660 if( !pTab ){ | |
| 661 sqlite3Error(db, SQLITE_MISUSE, 0); | |
| 662 sqlite3_mutex_leave(db->mutex); | |
| 663 return SQLITE_MISUSE; | |
| 664 } | |
| 665 assert( (pTab->tabFlags & TF_Virtual)!=0 ); | |
| 666 | |
| 667 pParse = sqlite3StackAllocZero(db, sizeof(*pParse)); | |
| 668 if( pParse==0 ){ | |
| 669 rc = SQLITE_NOMEM; | |
| 670 }else{ | |
| 671 pParse->declareVtab = 1; | |
| 672 pParse->db = db; | |
| 673 | |
| 674 if( | |
| 675 SQLITE_OK == sqlite3RunParser(pParse, zCreateTable, &zErr) && | |
| 676 pParse->pNewTable && | |
| 677 !pParse->pNewTable->pSelect && | |
| 678 (pParse->pNewTable->tabFlags & TF_Virtual)==0 | |
| 679 ){ | |
| 680 if( !pTab->aCol ){ | |
| 681 pTab->aCol = pParse->pNewTable->aCol; | |
| 682 pTab->nCol = pParse->pNewTable->nCol; | |
| 683 pParse->pNewTable->nCol = 0; | |
| 684 pParse->pNewTable->aCol = 0; | |
| 685 } | |
| 686 db->pVTab = 0; | |
| 687 } else { | |
| 688 sqlite3Error(db, SQLITE_ERROR, zErr); | |
| 689 sqlite3DbFree(db, zErr); | |
| 690 rc = SQLITE_ERROR; | |
| 691 } | |
| 692 pParse->declareVtab = 0; | |
| 693 | |
| 694 if( pParse->pVdbe ){ | |
| 695 sqlite3VdbeFinalize(pParse->pVdbe); | |
| 696 } | |
| 697 sqlite3DeleteTable(pParse->pNewTable); | |
| 698 sqlite3StackFree(db, pParse); | |
| 699 } | |
| 700 | |
| 701 assert( (rc&0xff)==rc ); | |
| 702 rc = sqlite3ApiExit(db, rc); | |
| 703 sqlite3_mutex_leave(db->mutex); | |
| 704 return rc; | |
| 705 } | |
| 706 | |
| 707 /* | |
| 708 ** This function is invoked by the vdbe to call the xDestroy method | |
| 709 ** of the virtual table named zTab in database iDb. This occurs | |
| 710 ** when a DROP TABLE is mentioned. | |
| 711 ** | |
| 712 ** This call is a no-op if zTab is not a virtual table. | |
| 713 */ | |
| 714 int sqlite3VtabCallDestroy(sqlite3 *db, int iDb, const char *zTab){ | |
| 715 int rc = SQLITE_OK; | |
| 716 Table *pTab; | |
| 717 | |
| 718 pTab = sqlite3FindTable(db, zTab, db->aDb[iDb].zName); | |
| 719 if( ALWAYS(pTab!=0 && pTab->pVTable!=0) ){ | |
| 720 VTable *p = vtabDisconnectAll(db, pTab); | |
| 721 | |
| 722 rc = sqlite3SafetyOff(db); | |
| 723 assert( rc==SQLITE_OK ); | |
| 724 rc = p->pMod->pModule->xDestroy(p->pVtab); | |
| 725 (void)sqlite3SafetyOn(db); | |
| 726 | |
| 727 /* Remove the sqlite3_vtab* from the aVTrans[] array, if applicable */ | |
| 728 if( rc==SQLITE_OK ){ | |
| 729 assert( pTab->pVTable==p && p->pNext==0 ); | |
| 730 p->pVtab = 0; | |
| 731 pTab->pVTable = 0; | |
| 732 sqlite3VtabUnlock(p); | |
| 733 } | |
| 734 } | |
| 735 | |
| 736 return rc; | |
| 737 } | |
| 738 | |
| 739 /* | |
| 740 ** This function invokes either the xRollback or xCommit method | |
| 741 ** of each of the virtual tables in the sqlite3.aVTrans array. The method | |
| 742 ** called is identified by the second argument, "offset", which is | |
| 743 ** the offset of the method to call in the sqlite3_module structure. | |
| 744 ** | |
| 745 ** The array is cleared after invoking the callbacks. | |
| 746 */ | |
| 747 static void callFinaliser(sqlite3 *db, int offset){ | |
| 748 int i; | |
| 749 if( db->aVTrans ){ | |
| 750 for(i=0; i<db->nVTrans; i++){ | |
| 751 VTable *pVTab = db->aVTrans[i]; | |
| 752 sqlite3_vtab *p = pVTab->pVtab; | |
| 753 if( p ){ | |
| 754 int (*x)(sqlite3_vtab *); | |
| 755 x = *(int (**)(sqlite3_vtab *))((char *)p->pModule + offset); | |
| 756 if( x ) x(p); | |
| 757 } | |
| 758 sqlite3VtabUnlock(pVTab); | |
| 759 } | |
| 760 sqlite3DbFree(db, db->aVTrans); | |
| 761 db->nVTrans = 0; | |
| 762 db->aVTrans = 0; | |
| 763 } | |
| 764 } | |
| 765 | |
| 766 /* | |
| 767 ** Invoke the xSync method of all virtual tables in the sqlite3.aVTrans | |
| 768 ** array. Return the error code for the first error that occurs, or | |
| 769 ** SQLITE_OK if all xSync operations are successful. | |
| 770 ** | |
| 771 ** Set *pzErrmsg to point to a buffer that should be released using | |
| 772 ** sqlite3DbFree() containing an error message, if one is available. | |
| 773 */ | |
| 774 int sqlite3VtabSync(sqlite3 *db, char **pzErrmsg){ | |
| 775 int i; | |
| 776 int rc = SQLITE_OK; | |
| 777 int rcsafety; | |
| 778 VTable **aVTrans = db->aVTrans; | |
| 779 | |
| 780 rc = sqlite3SafetyOff(db); | |
| 781 db->aVTrans = 0; | |
| 782 for(i=0; rc==SQLITE_OK && i<db->nVTrans; i++){ | |
| 783 int (*x)(sqlite3_vtab *); | |
| 784 sqlite3_vtab *pVtab = aVTrans[i]->pVtab; | |
| 785 if( pVtab && (x = pVtab->pModule->xSync)!=0 ){ | |
| 786 rc = x(pVtab); | |
| 787 sqlite3DbFree(db, *pzErrmsg); | |
| 788 *pzErrmsg = pVtab->zErrMsg; | |
| 789 pVtab->zErrMsg = 0; | |
| 790 } | |
| 791 } | |
| 792 db->aVTrans = aVTrans; | |
| 793 rcsafety = sqlite3SafetyOn(db); | |
| 794 | |
| 795 if( rc==SQLITE_OK ){ | |
| 796 rc = rcsafety; | |
| 797 } | |
| 798 return rc; | |
| 799 } | |
| 800 | |
| 801 /* | |
| 802 ** Invoke the xRollback method of all virtual tables in the | |
| 803 ** sqlite3.aVTrans array. Then clear the array itself. | |
| 804 */ | |
| 805 int sqlite3VtabRollback(sqlite3 *db){ | |
| 806 callFinaliser(db, offsetof(sqlite3_module,xRollback)); | |
| 807 return SQLITE_OK; | |
| 808 } | |
| 809 | |
| 810 /* | |
| 811 ** Invoke the xCommit method of all virtual tables in the | |
| 812 ** sqlite3.aVTrans array. Then clear the array itself. | |
| 813 */ | |
| 814 int sqlite3VtabCommit(sqlite3 *db){ | |
| 815 callFinaliser(db, offsetof(sqlite3_module,xCommit)); | |
| 816 return SQLITE_OK; | |
| 817 } | |
| 818 | |
| 819 /* | |
| 820 ** If the virtual table pVtab supports the transaction interface | |
| 821 ** (xBegin/xRollback/xCommit and optionally xSync) and a transaction is | |
| 822 ** not currently open, invoke the xBegin method now. | |
| 823 ** | |
| 824 ** If the xBegin call is successful, place the sqlite3_vtab pointer | |
| 825 ** in the sqlite3.aVTrans array. | |
| 826 */ | |
| 827 int sqlite3VtabBegin(sqlite3 *db, VTable *pVTab){ | |
| 828 int rc = SQLITE_OK; | |
| 829 const sqlite3_module *pModule; | |
| 830 | |
| 831 /* Special case: If db->aVTrans is NULL and db->nVTrans is greater | |
| 832 ** than zero, then this function is being called from within a | |
| 833 ** virtual module xSync() callback. It is illegal to write to | |
| 834 ** virtual module tables in this case, so return SQLITE_LOCKED. | |
| 835 */ | |
| 836 if( sqlite3VtabInSync(db) ){ | |
| 837 return SQLITE_LOCKED; | |
| 838 } | |
| 839 if( !pVTab ){ | |
| 840 return SQLITE_OK; | |
| 841 } | |
| 842 pModule = pVTab->pVtab->pModule; | |
| 843 | |
| 844 if( pModule->xBegin ){ | |
| 845 int i; | |
| 846 | |
| 847 | |
| 848 /* If pVtab is already in the aVTrans array, return early */ | |
| 849 for(i=0; i<db->nVTrans; i++){ | |
| 850 if( db->aVTrans[i]==pVTab ){ | |
| 851 return SQLITE_OK; | |
| 852 } | |
| 853 } | |
| 854 | |
| 855 /* Invoke the xBegin method */ | |
| 856 rc = pModule->xBegin(pVTab->pVtab); | |
| 857 if( rc==SQLITE_OK ){ | |
| 858 rc = addToVTrans(db, pVTab); | |
| 859 } | |
| 860 } | |
| 861 return rc; | |
| 862 } | |
| 863 | |
| 864 /* | |
| 865 ** The first parameter (pDef) is a function implementation. The | |
| 866 ** second parameter (pExpr) is the first argument to this function. | |
| 867 ** If pExpr is a column in a virtual table, then let the virtual | |
| 868 ** table implementation have an opportunity to overload the function. | |
| 869 ** | |
| 870 ** This routine is used to allow virtual table implementations to | |
| 871 ** overload MATCH, LIKE, GLOB, and REGEXP operators. | |
| 872 ** | |
| 873 ** Return either the pDef argument (indicating no change) or a | |
| 874 ** new FuncDef structure that is marked as ephemeral using the | |
| 875 ** SQLITE_FUNC_EPHEM flag. | |
| 876 */ | |
| 877 FuncDef *sqlite3VtabOverloadFunction( | |
| 878 sqlite3 *db, /* Database connection for reporting malloc problems */ | |
| 879 FuncDef *pDef, /* Function to possibly overload */ | |
| 880 int nArg, /* Number of arguments to the function */ | |
| 881 Expr *pExpr /* First argument to the function */ | |
| 882 ){ | |
| 883 Table *pTab; | |
| 884 sqlite3_vtab *pVtab; | |
| 885 sqlite3_module *pMod; | |
| 886 void (*xFunc)(sqlite3_context*,int,sqlite3_value**) = 0; | |
| 887 void *pArg = 0; | |
| 888 FuncDef *pNew; | |
| 889 int rc = 0; | |
| 890 char *zLowerName; | |
| 891 unsigned char *z; | |
| 892 | |
| 893 | |
| 894 /* Check to see the left operand is a column in a virtual table */ | |
| 895 if( NEVER(pExpr==0) ) return pDef; | |
| 896 if( pExpr->op!=TK_COLUMN ) return pDef; | |
| 897 pTab = pExpr->pTab; | |
| 898 if( NEVER(pTab==0) ) return pDef; | |
| 899 if( (pTab->tabFlags & TF_Virtual)==0 ) return pDef; | |
| 900 pVtab = sqlite3GetVTable(db, pTab)->pVtab; | |
| 901 assert( pVtab!=0 ); | |
| 902 assert( pVtab->pModule!=0 ); | |
| 903 pMod = (sqlite3_module *)pVtab->pModule; | |
| 904 if( pMod->xFindFunction==0 ) return pDef; | |
| 905 | |
| 906 /* Call the xFindFunction method on the virtual table implementation | |
| 907 ** to see if the implementation wants to overload this function | |
| 908 */ | |
| 909 zLowerName = sqlite3DbStrDup(db, pDef->zName); | |
| 910 if( zLowerName ){ | |
| 911 for(z=(unsigned char*)zLowerName; *z; z++){ | |
| 912 *z = sqlite3UpperToLower[*z]; | |
| 913 } | |
| 914 rc = pMod->xFindFunction(pVtab, nArg, zLowerName, &xFunc, &pArg); | |
| 915 sqlite3DbFree(db, zLowerName); | |
| 916 } | |
| 917 if( rc==0 ){ | |
| 918 return pDef; | |
| 919 } | |
| 920 | |
| 921 /* Create a new ephemeral function definition for the overloaded | |
| 922 ** function */ | |
| 923 pNew = sqlite3DbMallocZero(db, sizeof(*pNew) | |
| 924 + sqlite3Strlen30(pDef->zName) + 1); | |
| 925 if( pNew==0 ){ | |
| 926 return pDef; | |
| 927 } | |
| 928 *pNew = *pDef; | |
| 929 pNew->zName = (char *)&pNew[1]; | |
| 930 memcpy(pNew->zName, pDef->zName, sqlite3Strlen30(pDef->zName)+1); | |
| 931 pNew->xFunc = xFunc; | |
| 932 pNew->pUserData = pArg; | |
| 933 pNew->flags |= SQLITE_FUNC_EPHEM; | |
| 934 return pNew; | |
| 935 } | |
| 936 | |
| 937 /* | |
| 938 ** Make sure virtual table pTab is contained in the pParse->apVirtualLock[] | |
| 939 ** array so that an OP_VBegin will get generated for it. Add pTab to the | |
| 940 ** array if it is missing. If pTab is already in the array, this routine | |
| 941 ** is a no-op. | |
| 942 */ | |
| 943 void sqlite3VtabMakeWritable(Parse *pParse, Table *pTab){ | |
| 944 Parse *pToplevel = sqlite3ParseToplevel(pParse); | |
| 945 int i, n; | |
| 946 Table **apVtabLock; | |
| 947 | |
| 948 assert( IsVirtual(pTab) ); | |
| 949 for(i=0; i<pToplevel->nVtabLock; i++){ | |
| 950 if( pTab==pToplevel->apVtabLock[i] ) return; | |
| 951 } | |
| 952 n = (pToplevel->nVtabLock+1)*sizeof(pToplevel->apVtabLock[0]); | |
| 953 apVtabLock = sqlite3_realloc(pToplevel->apVtabLock, n); | |
| 954 if( apVtabLock ){ | |
| 955 pToplevel->apVtabLock = apVtabLock; | |
| 956 pToplevel->apVtabLock[pToplevel->nVtabLock++] = pTab; | |
| 957 }else{ | |
| 958 pToplevel->db->mallocFailed = 1; | |
| 959 } | |
| 960 } | |
| 961 | |
| 962 #endif /* SQLITE_OMIT_VIRTUALTABLE */ | |
| OLD | NEW |
|---|
Chromium Code Reviews
Issue 3108030:
Move bundled copy of sqlite one level deeper to better separate it... (Closed)
Base URL: svn://svn.chromium.org/chrome/trunk/src/