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Diffstat (limited to 'src/vtab.c')
| -rw-r--r-- | src/vtab.c | 1066 |
1 files changed, 1066 insertions, 0 deletions
diff --git a/src/vtab.c b/src/vtab.c new file mode 100644 index 0000000..8119cb5 --- /dev/null +++ b/src/vtab.c @@ -0,0 +1,1066 @@ +/* +** 2006 June 10 +** +** The author disclaims copyright to this source code. In place of +** a legal notice, here is a blessing: +** +** May you do good and not evil. +** May you find forgiveness for yourself and forgive others. +** May you share freely, never taking more than you give. +** +************************************************************************* +** This file contains code used to help implement virtual tables. +*/ +#ifndef SQLITE_OMIT_VIRTUALTABLE +#include "sqliteInt.h" + +/* +** Before a virtual table xCreate() or xConnect() method is invoked, the +** sqlite3.pVtabCtx member variable is set to point to an instance of +** this struct allocated on the stack. It is used by the implementation of +** the sqlite3_declare_vtab() and sqlite3_vtab_config() APIs, both of which +** are invoked only from within xCreate and xConnect methods. +*/ +struct VtabCtx { + Table *pTab; + VTable *pVTable; +}; + +/* +** The actual function that does the work of creating a new module. +** This function implements the sqlite3_create_module() and +** sqlite3_create_module_v2() interfaces. +*/ +static int createModule( + sqlite3 *db, /* Database in which module is registered */ + const char *zName, /* Name assigned to this module */ + const sqlite3_module *pModule, /* The definition of the module */ + void *pAux, /* Context pointer for xCreate/xConnect */ + void (*xDestroy)(void *) /* Module destructor function */ +){ + int rc, nName; + Module *pMod; + + sqlite3_mutex_enter(db->mutex); + nName = sqlite3Strlen30(zName); + pMod = (Module *)sqlite3DbMallocRaw(db, sizeof(Module) + nName + 1); + if( pMod ){ + Module *pDel; + char *zCopy = (char *)(&pMod[1]); + memcpy(zCopy, zName, nName+1); + pMod->zName = zCopy; + pMod->pModule = pModule; + pMod->pAux = pAux; + pMod->xDestroy = xDestroy; + pDel = (Module *)sqlite3HashInsert(&db->aModule, zCopy, nName, (void*)pMod); + if( pDel && pDel->xDestroy ){ + sqlite3ResetInternalSchema(db, -1); + pDel->xDestroy(pDel->pAux); + } + sqlite3DbFree(db, pDel); + if( pDel==pMod ){ + db->mallocFailed = 1; + } + }else if( xDestroy ){ + xDestroy(pAux); + } + rc = sqlite3ApiExit(db, SQLITE_OK); + sqlite3_mutex_leave(db->mutex); + return rc; +} + + +/* +** External API function used to create a new virtual-table module. +*/ +int sqlite3_create_module( + sqlite3 *db, /* Database in which module is registered */ + const char *zName, /* Name assigned to this module */ + const sqlite3_module *pModule, /* The definition of the module */ + void *pAux /* Context pointer for xCreate/xConnect */ +){ + return createModule(db, zName, pModule, pAux, 0); +} + +/* +** External API function used to create a new virtual-table module. +*/ +int sqlite3_create_module_v2( + sqlite3 *db, /* Database in which module is registered */ + const char *zName, /* Name assigned to this module */ + const sqlite3_module *pModule, /* The definition of the module */ + void *pAux, /* Context pointer for xCreate/xConnect */ + void (*xDestroy)(void *) /* Module destructor function */ +){ + return createModule(db, zName, pModule, pAux, xDestroy); +} + +/* +** Lock the virtual table so that it cannot be disconnected. +** Locks nest. Every lock should have a corresponding unlock. +** If an unlock is omitted, resources leaks will occur. +** +** If a disconnect is attempted while a virtual table is locked, +** the disconnect is deferred until all locks have been removed. +*/ +void sqlite3VtabLock(VTable *pVTab){ + pVTab->nRef++; +} + + +/* +** pTab is a pointer to a Table structure representing a virtual-table. +** Return a pointer to the VTable object used by connection db to access +** this virtual-table, if one has been created, or NULL otherwise. +*/ +VTable *sqlite3GetVTable(sqlite3 *db, Table *pTab){ + VTable *pVtab; + assert( IsVirtual(pTab) ); + for(pVtab=pTab->pVTable; pVtab && pVtab->db!=db; pVtab=pVtab->pNext); + return pVtab; +} + +/* +** Decrement the ref-count on a virtual table object. When the ref-count +** reaches zero, call the xDisconnect() method to delete the object. +*/ +void sqlite3VtabUnlock(VTable *pVTab){ + sqlite3 *db = pVTab->db; + + assert( db ); + assert( pVTab->nRef>0 ); + assert( sqlite3SafetyCheckOk(db) ); + + pVTab->nRef--; + if( pVTab->nRef==0 ){ + sqlite3_vtab *p = pVTab->pVtab; + if( p ){ + p->pModule->xDisconnect(p); + } + sqlite3DbFree(db, pVTab); + } +} + +/* +** Table p is a virtual table. This function moves all elements in the +** p->pVTable list to the sqlite3.pDisconnect lists of their associated +** database connections to be disconnected at the next opportunity. +** Except, if argument db is not NULL, then the entry associated with +** connection db is left in the p->pVTable list. +*/ +static VTable *vtabDisconnectAll(sqlite3 *db, Table *p){ + VTable *pRet = 0; + VTable *pVTable = p->pVTable; + p->pVTable = 0; + + /* Assert that the mutex (if any) associated with the BtShared database + ** that contains table p is held by the caller. See header comments + ** above function sqlite3VtabUnlockList() for an explanation of why + ** this makes it safe to access the sqlite3.pDisconnect list of any + ** database connection that may have an entry in the p->pVTable list. + */ + assert( db==0 || sqlite3SchemaMutexHeld(db, 0, p->pSchema) ); + + while( pVTable ){ + sqlite3 *db2 = pVTable->db; + VTable *pNext = pVTable->pNext; + assert( db2 ); + if( db2==db ){ + pRet = pVTable; + p->pVTable = pRet; + pRet->pNext = 0; + }else{ + pVTable->pNext = db2->pDisconnect; + db2->pDisconnect = pVTable; + } + pVTable = pNext; + } + + assert( !db || pRet ); + return pRet; +} + + +/* +** Disconnect all the virtual table objects in the sqlite3.pDisconnect list. +** +** This function may only be called when the mutexes associated with all +** shared b-tree databases opened using connection db are held by the +** caller. This is done to protect the sqlite3.pDisconnect list. The +** sqlite3.pDisconnect list is accessed only as follows: +** +** 1) By this function. In this case, all BtShared mutexes and the mutex +** associated with the database handle itself must be held. +** +** 2) By function vtabDisconnectAll(), when it adds a VTable entry to +** the sqlite3.pDisconnect list. In this case either the BtShared mutex +** associated with the database the virtual table is stored in is held +** or, if the virtual table is stored in a non-sharable database, then +** the database handle mutex is held. +** +** As a result, a sqlite3.pDisconnect cannot be accessed simultaneously +** by multiple threads. It is thread-safe. +*/ +void sqlite3VtabUnlockList(sqlite3 *db){ + VTable *p = db->pDisconnect; + db->pDisconnect = 0; + + assert( sqlite3BtreeHoldsAllMutexes(db) ); + assert( sqlite3_mutex_held(db->mutex) ); + + if( p ){ + sqlite3ExpirePreparedStatements(db); + do { + VTable *pNext = p->pNext; + sqlite3VtabUnlock(p); + p = pNext; + }while( p ); + } +} + +/* +** Clear any and all virtual-table information from the Table record. +** This routine is called, for example, just before deleting the Table +** record. +** +** Since it is a virtual-table, the Table structure contains a pointer +** to the head of a linked list of VTable structures. Each VTable +** structure is associated with a single sqlite3* user of the schema. +** The reference count of the VTable structure associated with database +** connection db is decremented immediately (which may lead to the +** structure being xDisconnected and free). Any other VTable structures +** in the list are moved to the sqlite3.pDisconnect list of the associated +** database connection. +*/ +void sqlite3VtabClear(sqlite3 *db, Table *p){ + if( !db || db->pnBytesFreed==0 ) vtabDisconnectAll(0, p); + if( p->azModuleArg ){ + int i; + for(i=0; i<p->nModuleArg; i++){ + sqlite3DbFree(db, p->azModuleArg[i]); + } + sqlite3DbFree(db, p->azModuleArg); + } +} + +/* +** Add a new module argument to pTable->azModuleArg[]. +** The string is not copied - the pointer is stored. The +** string will be freed automatically when the table is +** deleted. +*/ +static void addModuleArgument(sqlite3 *db, Table *pTable, char *zArg){ + int i = pTable->nModuleArg++; + int nBytes = sizeof(char *)*(1+pTable->nModuleArg); + char **azModuleArg; + azModuleArg = sqlite3DbRealloc(db, pTable->azModuleArg, nBytes); + if( azModuleArg==0 ){ + int j; + for(j=0; j<i; j++){ + sqlite3DbFree(db, pTable->azModuleArg[j]); + } + sqlite3DbFree(db, zArg); + sqlite3DbFree(db, pTable->azModuleArg); + pTable->nModuleArg = 0; + }else{ + azModuleArg[i] = zArg; + azModuleArg[i+1] = 0; + } + pTable->azModuleArg = azModuleArg; +} + +/* +** The parser calls this routine when it first sees a CREATE VIRTUAL TABLE +** statement. The module name has been parsed, but the optional list +** of parameters that follow the module name are still pending. +*/ +void sqlite3VtabBeginParse( + Parse *pParse, /* Parsing context */ + Token *pName1, /* Name of new table, or database name */ + Token *pName2, /* Name of new table or NULL */ + Token *pModuleName /* Name of the module for the virtual table */ +){ + int iDb; /* The database the table is being created in */ + Table *pTable; /* The new virtual table */ + sqlite3 *db; /* Database connection */ + + sqlite3StartTable(pParse, pName1, pName2, 0, 0, 1, 0); + pTable = pParse->pNewTable; + if( pTable==0 ) return; + assert( 0==pTable->pIndex ); + + db = pParse->db; + iDb = sqlite3SchemaToIndex(db, pTable->pSchema); + assert( iDb>=0 ); + + pTable->tabFlags |= TF_Virtual; + pTable->nModuleArg = 0; + addModuleArgument(db, pTable, sqlite3NameFromToken(db, pModuleName)); + addModuleArgument(db, pTable, sqlite3DbStrDup(db, db->aDb[iDb].zName)); + addModuleArgument(db, pTable, sqlite3DbStrDup(db, pTable->zName)); + pParse->sNameToken.n = (int)(&pModuleName->z[pModuleName->n] - pName1->z); + +#ifndef SQLITE_OMIT_AUTHORIZATION + /* Creating a virtual table invokes the authorization callback twice. + ** The first invocation, to obtain permission to INSERT a row into the + ** sqlite_master table, has already been made by sqlite3StartTable(). + ** The second call, to obtain permission to create the table, is made now. + */ + if( pTable->azModuleArg ){ + sqlite3AuthCheck(pParse, SQLITE_CREATE_VTABLE, pTable->zName, + pTable->azModuleArg[0], pParse->db->aDb[iDb].zName); + } +#endif +} + +/* +** This routine takes the module argument that has been accumulating +** in pParse->zArg[] and appends it to the list of arguments on the +** virtual table currently under construction in pParse->pTable. +*/ +static void addArgumentToVtab(Parse *pParse){ + if( pParse->sArg.z && ALWAYS(pParse->pNewTable) ){ + const char *z = (const char*)pParse->sArg.z; + int n = pParse->sArg.n; + sqlite3 *db = pParse->db; + addModuleArgument(db, pParse->pNewTable, sqlite3DbStrNDup(db, z, n)); + } +} + +/* +** The parser calls this routine after the CREATE VIRTUAL TABLE statement +** has been completely parsed. +*/ +void sqlite3VtabFinishParse(Parse *pParse, Token *pEnd){ + Table *pTab = pParse->pNewTable; /* The table being constructed */ + sqlite3 *db = pParse->db; /* The database connection */ + + if( pTab==0 ) return; + addArgumentToVtab(pParse); + pParse->sArg.z = 0; + if( pTab->nModuleArg<1 ) return; + + /* If the CREATE VIRTUAL TABLE statement is being entered for the + ** first time (in other words if the virtual table is actually being + ** created now instead of just being read out of sqlite_master) then + ** do additional initialization work and store the statement text + ** in the sqlite_master table. + */ + if( !db->init.busy ){ + char *zStmt; + char *zWhere; + int iDb; + Vdbe *v; + + /* Compute the complete text of the CREATE VIRTUAL TABLE statement */ + if( pEnd ){ + pParse->sNameToken.n = (int)(pEnd->z - pParse->sNameToken.z) + pEnd->n; + } + zStmt = sqlite3MPrintf(db, "CREATE VIRTUAL TABLE %T", &pParse->sNameToken); + + /* A slot for the record has already been allocated in the + ** SQLITE_MASTER table. We just need to update that slot with all + ** the information we've collected. + ** + ** The VM register number pParse->regRowid holds the rowid of an + ** entry in the sqlite_master table tht was created for this vtab + ** by sqlite3StartTable(). + */ + iDb = sqlite3SchemaToIndex(db, pTab->pSchema); + sqlite3NestedParse(pParse, + "UPDATE %Q.%s " + "SET type='table', name=%Q, tbl_name=%Q, rootpage=0, sql=%Q " + "WHERE rowid=#%d", + db->aDb[iDb].zName, SCHEMA_TABLE(iDb), + pTab->zName, + pTab->zName, + zStmt, + pParse->regRowid + ); + sqlite3DbFree(db, zStmt); + v = sqlite3GetVdbe(pParse); + sqlite3ChangeCookie(pParse, iDb); + + sqlite3VdbeAddOp2(v, OP_Expire, 0, 0); + zWhere = sqlite3MPrintf(db, "name='%q' AND type='table'", pTab->zName); + sqlite3VdbeAddParseSchemaOp(v, iDb, zWhere); + sqlite3VdbeAddOp4(v, OP_VCreate, iDb, 0, 0, + pTab->zName, sqlite3Strlen30(pTab->zName) + 1); + } + + /* If we are rereading the sqlite_master table create the in-memory + ** record of the table. The xConnect() method is not called until + ** the first time the virtual table is used in an SQL statement. This + ** allows a schema that contains virtual tables to be loaded before + ** the required virtual table implementations are registered. */ + else { + Table *pOld; + Schema *pSchema = pTab->pSchema; + const char *zName = pTab->zName; + int nName = sqlite3Strlen30(zName); + assert( sqlite3SchemaMutexHeld(db, 0, pSchema) ); + pOld = sqlite3HashInsert(&pSchema->tblHash, zName, nName, pTab); + if( pOld ){ + db->mallocFailed = 1; + assert( pTab==pOld ); /* Malloc must have failed inside HashInsert() */ + return; + } + pParse->pNewTable = 0; + } +} + +/* +** The parser calls this routine when it sees the first token +** of an argument to the module name in a CREATE VIRTUAL TABLE statement. +*/ +void sqlite3VtabArgInit(Parse *pParse){ + addArgumentToVtab(pParse); + pParse->sArg.z = 0; + pParse->sArg.n = 0; +} + +/* +** The parser calls this routine for each token after the first token +** in an argument to the module name in a CREATE VIRTUAL TABLE statement. +*/ +void sqlite3VtabArgExtend(Parse *pParse, Token *p){ + Token *pArg = &pParse->sArg; + if( pArg->z==0 ){ + pArg->z = p->z; + pArg->n = p->n; + }else{ + assert(pArg->z < p->z); + pArg->n = (int)(&p->z[p->n] - pArg->z); + } +} + +/* +** Invoke a virtual table constructor (either xCreate or xConnect). The +** pointer to the function to invoke is passed as the fourth parameter +** to this procedure. +*/ +static int vtabCallConstructor( + sqlite3 *db, + Table *pTab, + Module *pMod, + int (*xConstruct)(sqlite3*,void*,int,const char*const*,sqlite3_vtab**,char**), + char **pzErr +){ + VtabCtx sCtx; + VTable *pVTable; + int rc; + const char *const*azArg = (const char *const*)pTab->azModuleArg; + int nArg = pTab->nModuleArg; + char *zErr = 0; + char *zModuleName = sqlite3MPrintf(db, "%s", pTab->zName); + + if( !zModuleName ){ + return SQLITE_NOMEM; + } + + pVTable = sqlite3DbMallocZero(db, sizeof(VTable)); + if( !pVTable ){ + sqlite3DbFree(db, zModuleName); + return SQLITE_NOMEM; + } + pVTable->db = db; + pVTable->pMod = pMod; + + /* Invoke the virtual table constructor */ + assert( &db->pVtabCtx ); + assert( xConstruct ); + sCtx.pTab = pTab; + sCtx.pVTable = pVTable; + db->pVtabCtx = &sCtx; + rc = xConstruct(db, pMod->pAux, nArg, azArg, &pVTable->pVtab, &zErr); + db->pVtabCtx = 0; + if( rc==SQLITE_NOMEM ) db->mallocFailed = 1; + + if( SQLITE_OK!=rc ){ + if( zErr==0 ){ + *pzErr = sqlite3MPrintf(db, "vtable constructor failed: %s", zModuleName); + }else { + *pzErr = sqlite3MPrintf(db, "%s", zErr); + sqlite3_free(zErr); + } + sqlite3DbFree(db, pVTable); + }else if( ALWAYS(pVTable->pVtab) ){ + /* Justification of ALWAYS(): A correct vtab constructor must allocate + ** the sqlite3_vtab object if successful. */ + pVTable->pVtab->pModule = pMod->pModule; + pVTable->nRef = 1; + if( sCtx.pTab ){ + const char *zFormat = "vtable constructor did not declare schema: %s"; + *pzErr = sqlite3MPrintf(db, zFormat, pTab->zName); + sqlite3VtabUnlock(pVTable); + rc = SQLITE_ERROR; + }else{ + int iCol; + /* If everything went according to plan, link the new VTable structure + ** into the linked list headed by pTab->pVTable. Then loop through the + ** columns of the table to see if any of them contain the token "hidden". + ** If so, set the Column.isHidden flag and remove the token from + ** the type string. */ + pVTable->pNext = pTab->pVTable; + pTab->pVTable = pVTable; + + for(iCol=0; iCol<pTab->nCol; iCol++){ + char *zType = pTab->aCol[iCol].zType; + int nType; + int i = 0; + if( !zType ) continue; + nType = sqlite3Strlen30(zType); + if( sqlite3StrNICmp("hidden", zType, 6)||(zType[6] && zType[6]!=' ') ){ + for(i=0; i<nType; i++){ + if( (0==sqlite3StrNICmp(" hidden", &zType[i], 7)) + && (zType[i+7]=='\0' || zType[i+7]==' ') + ){ + i++; + break; + } + } + } + if( i<nType ){ + int j; + int nDel = 6 + (zType[i+6] ? 1 : 0); + for(j=i; (j+nDel)<=nType; j++){ + zType[j] = zType[j+nDel]; + } + if( zType[i]=='\0' && i>0 ){ + assert(zType[i-1]==' '); + zType[i-1] = '\0'; + } + pTab->aCol[iCol].isHidden = 1; + } + } + } + } + + sqlite3DbFree(db, zModuleName); + return rc; +} + +/* +** This function is invoked by the parser to call the xConnect() method +** of the virtual table pTab. If an error occurs, an error code is returned +** and an error left in pParse. +** +** This call is a no-op if table pTab is not a virtual table. +*/ +int sqlite3VtabCallConnect(Parse *pParse, Table *pTab){ + sqlite3 *db = pParse->db; + const char *zMod; + Module *pMod; + int rc; + + assert( pTab ); + if( (pTab->tabFlags & TF_Virtual)==0 || sqlite3GetVTable(db, pTab) ){ + return SQLITE_OK; + } + + /* Locate the required virtual table module */ + zMod = pTab->azModuleArg[0]; + pMod = (Module*)sqlite3HashFind(&db->aModule, zMod, sqlite3Strlen30(zMod)); + + if( !pMod ){ + const char *zModule = pTab->azModuleArg[0]; + sqlite3ErrorMsg(pParse, "no such module: %s", zModule); + rc = SQLITE_ERROR; + }else{ + char *zErr = 0; + rc = vtabCallConstructor(db, pTab, pMod, pMod->pModule->xConnect, &zErr); + if( rc!=SQLITE_OK ){ + sqlite3ErrorMsg(pParse, "%s", zErr); + } + sqlite3DbFree(db, zErr); + } + + return rc; +} +/* +** Grow the db->aVTrans[] array so that there is room for at least one +** more v-table. Return SQLITE_NOMEM if a malloc fails, or SQLITE_OK otherwise. +*/ +static int growVTrans(sqlite3 *db){ + const int ARRAY_INCR = 5; + + /* Grow the sqlite3.aVTrans array if required */ + if( (db->nVTrans%ARRAY_INCR)==0 ){ + VTable **aVTrans; + int nBytes = sizeof(sqlite3_vtab *) * (db->nVTrans + ARRAY_INCR); + aVTrans = sqlite3DbRealloc(db, (void *)db->aVTrans, nBytes); + if( !aVTrans ){ + return SQLITE_NOMEM; + } + memset(&aVTrans[db->nVTrans], 0, sizeof(sqlite3_vtab *)*ARRAY_INCR); + db->aVTrans = aVTrans; + } + + return SQLITE_OK; +} + +/* +** Add the virtual table pVTab to the array sqlite3.aVTrans[]. Space should +** have already been reserved using growVTrans(). +*/ +static void addToVTrans(sqlite3 *db, VTable *pVTab){ + /* Add pVtab to the end of sqlite3.aVTrans */ + db->aVTrans[db->nVTrans++] = pVTab; + sqlite3VtabLock(pVTab); +} + +/* +** This function is invoked by the vdbe to call the xCreate method +** of the virtual table named zTab in database iDb. +** +** If an error occurs, *pzErr is set to point an an English language +** description of the error and an SQLITE_XXX error code is returned. +** In this case the caller must call sqlite3DbFree(db, ) on *pzErr. +*/ +int sqlite3VtabCallCreate(sqlite3 *db, int iDb, const char *zTab, char **pzErr){ + int rc = SQLITE_OK; + Table *pTab; + Module *pMod; + const char *zMod; + + pTab = sqlite3FindTable(db, zTab, db->aDb[iDb].zName); + assert( pTab && (pTab->tabFlags & TF_Virtual)!=0 && !pTab->pVTable ); + + /* Locate the required virtual table module */ + zMod = pTab->azModuleArg[0]; + pMod = (Module*)sqlite3HashFind(&db->aModule, zMod, sqlite3Strlen30(zMod)); + + /* If the module has been registered and includes a Create method, + ** invoke it now. If the module has not been registered, return an + ** error. Otherwise, do nothing. + */ + if( !pMod ){ + *pzErr = sqlite3MPrintf(db, "no such module: %s", zMod); + rc = SQLITE_ERROR; + }else{ + rc = vtabCallConstructor(db, pTab, pMod, pMod->pModule->xCreate, pzErr); + } + + /* Justification of ALWAYS(): The xConstructor method is required to + ** create a valid sqlite3_vtab if it returns SQLITE_OK. */ + if( rc==SQLITE_OK && ALWAYS(sqlite3GetVTable(db, pTab)) ){ + rc = growVTrans(db); + if( rc==SQLITE_OK ){ + addToVTrans(db, sqlite3GetVTable(db, pTab)); + } + } + + return rc; +} + +/* +** This function is used to set the schema of a virtual table. It is only +** valid to call this function from within the xCreate() or xConnect() of a +** virtual table module. +*/ +int sqlite3_declare_vtab(sqlite3 *db, const char *zCreateTable){ + Parse *pParse; + + int rc = SQLITE_OK; + Table *pTab; + char *zErr = 0; + + sqlite3_mutex_enter(db->mutex); + if( !db->pVtabCtx || !(pTab = db->pVtabCtx->pTab) ){ + sqlite3Error(db, SQLITE_MISUSE, 0); + sqlite3_mutex_leave(db->mutex); + return SQLITE_MISUSE_BKPT; + } + assert( (pTab->tabFlags & TF_Virtual)!=0 ); + + pParse = sqlite3StackAllocZero(db, sizeof(*pParse)); + if( pParse==0 ){ + rc = SQLITE_NOMEM; + }else{ + pParse->declareVtab = 1; + pParse->db = db; + pParse->nQueryLoop = 1; + + if( SQLITE_OK==sqlite3RunParser(pParse, zCreateTable, &zErr) + && pParse->pNewTable + && !db->mallocFailed + && !pParse->pNewTable->pSelect + && (pParse->pNewTable->tabFlags & TF_Virtual)==0 + ){ + if( !pTab->aCol ){ + pTab->aCol = pParse->pNewTable->aCol; + pTab->nCol = pParse->pNewTable->nCol; + pParse->pNewTable->nCol = 0; + pParse->pNewTable->aCol = 0; + } + db->pVtabCtx->pTab = 0; + }else{ + sqlite3Error(db, SQLITE_ERROR, (zErr ? "%s" : 0), zErr); + sqlite3DbFree(db, zErr); + rc = SQLITE_ERROR; + } + pParse->declareVtab = 0; + + if( pParse->pVdbe ){ + sqlite3VdbeFinalize(pParse->pVdbe); + } + sqlite3DeleteTable(db, pParse->pNewTable); + sqlite3StackFree(db, pParse); + } + + assert( (rc&0xff)==rc ); + rc = sqlite3ApiExit(db, rc); + sqlite3_mutex_leave(db->mutex); + return rc; +} + +/* +** This function is invoked by the vdbe to call the xDestroy method +** of the virtual table named zTab in database iDb. This occurs +** when a DROP TABLE is mentioned. +** +** This call is a no-op if zTab is not a virtual table. +*/ +int sqlite3VtabCallDestroy(sqlite3 *db, int iDb, const char *zTab){ + int rc = SQLITE_OK; + Table *pTab; + + pTab = sqlite3FindTable(db, zTab, db->aDb[iDb].zName); + if( ALWAYS(pTab!=0 && pTab->pVTable!=0) ){ + VTable *p = vtabDisconnectAll(db, pTab); + + assert( rc==SQLITE_OK ); + rc = p->pMod->pModule->xDestroy(p->pVtab); + + /* Remove the sqlite3_vtab* from the aVTrans[] array, if applicable */ + if( rc==SQLITE_OK ){ + assert( pTab->pVTable==p && p->pNext==0 ); + p->pVtab = 0; + pTab->pVTable = 0; + sqlite3VtabUnlock(p); + } + } + + return rc; +} + +/* +** This function invokes either the xRollback or xCommit method +** of each of the virtual tables in the sqlite3.aVTrans array. The method +** called is identified by the second argument, "offset", which is +** the offset of the method to call in the sqlite3_module structure. +** +** The array is cleared after invoking the callbacks. +*/ +static void callFinaliser(sqlite3 *db, int offset){ + int i; + if( db->aVTrans ){ + for(i=0; i<db->nVTrans; i++){ + VTable *pVTab = db->aVTrans[i]; + sqlite3_vtab *p = pVTab->pVtab; + if( p ){ + int (*x)(sqlite3_vtab *); + x = *(int (**)(sqlite3_vtab *))((char *)p->pModule + offset); + if( x ) x(p); + } + pVTab->iSavepoint = 0; + sqlite3VtabUnlock(pVTab); + } + sqlite3DbFree(db, db->aVTrans); + db->nVTrans = 0; + db->aVTrans = 0; + } +} + +/* +** Invoke the xSync method of all virtual tables in the sqlite3.aVTrans +** array. Return the error code for the first error that occurs, or +** SQLITE_OK if all xSync operations are successful. +** +** Set *pzErrmsg to point to a buffer that should be released using +** sqlite3DbFree() containing an error message, if one is available. +*/ +int sqlite3VtabSync(sqlite3 *db, char **pzErrmsg){ + int i; + int rc = SQLITE_OK; + VTable **aVTrans = db->aVTrans; + + db->aVTrans = 0; + for(i=0; rc==SQLITE_OK && i<db->nVTrans; i++){ + int (*x)(sqlite3_vtab *); + sqlite3_vtab *pVtab = aVTrans[i]->pVtab; + if( pVtab && (x = pVtab->pModule->xSync)!=0 ){ + rc = x(pVtab); + sqlite3DbFree(db, *pzErrmsg); + *pzErrmsg = sqlite3DbStrDup(db, pVtab->zErrMsg); + sqlite3_free(pVtab->zErrMsg); + } + } + db->aVTrans = aVTrans; + return rc; +} + +/* +** Invoke the xRollback method of all virtual tables in the +** sqlite3.aVTrans array. Then clear the array itself. +*/ +int sqlite3VtabRollback(sqlite3 *db){ + callFinaliser(db, offsetof(sqlite3_module,xRollback)); + return SQLITE_OK; +} + +/* +** Invoke the xCommit method of all virtual tables in the +** sqlite3.aVTrans array. Then clear the array itself. +*/ +int sqlite3VtabCommit(sqlite3 *db){ + callFinaliser(db, offsetof(sqlite3_module,xCommit)); + return SQLITE_OK; +} + +/* +** If the virtual table pVtab supports the transaction interface +** (xBegin/xRollback/xCommit and optionally xSync) and a transaction is +** not currently open, invoke the xBegin method now. +** +** If the xBegin call is successful, place the sqlite3_vtab pointer +** in the sqlite3.aVTrans array. +*/ +int sqlite3VtabBegin(sqlite3 *db, VTable *pVTab){ + int rc = SQLITE_OK; + const sqlite3_module *pModule; + + /* Special case: If db->aVTrans is NULL and db->nVTrans is greater + ** than zero, then this function is being called from within a + ** virtual module xSync() callback. It is illegal to write to + ** virtual module tables in this case, so return SQLITE_LOCKED. + */ + if( sqlite3VtabInSync(db) ){ + return SQLITE_LOCKED; + } + if( !pVTab ){ + return SQLITE_OK; + } + pModule = pVTab->pVtab->pModule; + + if( pModule->xBegin ){ + int i; + + /* If pVtab is already in the aVTrans array, return early */ + for(i=0; i<db->nVTrans; i++){ + if( db->aVTrans[i]==pVTab ){ + return SQLITE_OK; + } + } + + /* Invoke the xBegin method. If successful, add the vtab to the + ** sqlite3.aVTrans[] array. */ + rc = growVTrans(db); + if( rc==SQLITE_OK ){ + rc = pModule->xBegin(pVTab->pVtab); + if( rc==SQLITE_OK ){ + addToVTrans(db, pVTab); + } + } + } + return rc; +} + +/* +** Invoke either the xSavepoint, xRollbackTo or xRelease method of all +** virtual tables that currently have an open transaction. Pass iSavepoint +** as the second argument to the virtual table method invoked. +** +** If op is SAVEPOINT_BEGIN, the xSavepoint method is invoked. If it is +** SAVEPOINT_ROLLBACK, the xRollbackTo method. Otherwise, if op is +** SAVEPOINT_RELEASE, then the xRelease method of each virtual table with +** an open transaction is invoked. +** +** If any virtual table method returns an error code other than SQLITE_OK, +** processing is abandoned and the error returned to the caller of this +** function immediately. If all calls to virtual table methods are successful, +** SQLITE_OK is returned. +*/ +int sqlite3VtabSavepoint(sqlite3 *db, int op, int iSavepoint){ + int rc = SQLITE_OK; + + assert( op==SAVEPOINT_RELEASE||op==SAVEPOINT_ROLLBACK||op==SAVEPOINT_BEGIN ); + assert( iSavepoint>=0 ); + if( db->aVTrans ){ + int i; + for(i=0; rc==SQLITE_OK && i<db->nVTrans; i++){ + VTable *pVTab = db->aVTrans[i]; + const sqlite3_module *pMod = pVTab->pMod->pModule; + if( pVTab->pVtab && pMod->iVersion>=2 ){ + int (*xMethod)(sqlite3_vtab *, int); + switch( op ){ + case SAVEPOINT_BEGIN: + xMethod = pMod->xSavepoint; + pVTab->iSavepoint = iSavepoint+1; + break; + case SAVEPOINT_ROLLBACK: + xMethod = pMod->xRollbackTo; + break; + default: + xMethod = pMod->xRelease; + break; + } + if( xMethod && pVTab->iSavepoint>iSavepoint ){ + rc = xMethod(pVTab->pVtab, iSavepoint); + } + } + } + } + return rc; +} + +/* +** The first parameter (pDef) is a function implementation. The +** second parameter (pExpr) is the first argument to this function. +** If pExpr is a column in a virtual table, then let the virtual +** table implementation have an opportunity to overload the function. +** +** This routine is used to allow virtual table implementations to +** overload MATCH, LIKE, GLOB, and REGEXP operators. +** +** Return either the pDef argument (indicating no change) or a +** new FuncDef structure that is marked as ephemeral using the +** SQLITE_FUNC_EPHEM flag. +*/ +FuncDef *sqlite3VtabOverloadFunction( + sqlite3 *db, /* Database connection for reporting malloc problems */ + FuncDef *pDef, /* Function to possibly overload */ + int nArg, /* Number of arguments to the function */ + Expr *pExpr /* First argument to the function */ +){ + Table *pTab; + sqlite3_vtab *pVtab; + sqlite3_module *pMod; + void (*xFunc)(sqlite3_context*,int,sqlite3_value**) = 0; + void *pArg = 0; + FuncDef *pNew; + int rc = 0; + char *zLowerName; + unsigned char *z; + + + /* Check to see the left operand is a column in a virtual table */ + if( NEVER(pExpr==0) ) return pDef; + if( pExpr->op!=TK_COLUMN ) return pDef; + pTab = pExpr->pTab; + if( NEVER(pTab==0) ) return pDef; + if( (pTab->tabFlags & TF_Virtual)==0 ) return pDef; + pVtab = sqlite3GetVTable(db, pTab)->pVtab; + assert( pVtab!=0 ); + assert( pVtab->pModule!=0 ); + pMod = (sqlite3_module *)pVtab->pModule; + if( pMod->xFindFunction==0 ) return pDef; + + /* Call the xFindFunction method on the virtual table implementation + ** to see if the implementation wants to overload this function + */ + zLowerName = sqlite3DbStrDup(db, pDef->zName); + if( zLowerName ){ + for(z=(unsigned char*)zLowerName; *z; z++){ + *z = sqlite3UpperToLower[*z]; + } + rc = pMod->xFindFunction(pVtab, nArg, zLowerName, &xFunc, &pArg); + sqlite3DbFree(db, zLowerName); + } + if( rc==0 ){ + return pDef; + } + + /* Create a new ephemeral function definition for the overloaded + ** function */ + pNew = sqlite3DbMallocZero(db, sizeof(*pNew) + + sqlite3Strlen30(pDef->zName) + 1); + if( pNew==0 ){ + return pDef; + } + *pNew = *pDef; + pNew->zName = (char *)&pNew[1]; + memcpy(pNew->zName, pDef->zName, sqlite3Strlen30(pDef->zName)+1); + pNew->xFunc = xFunc; + pNew->pUserData = pArg; + pNew->flags |= SQLITE_FUNC_EPHEM; + return pNew; +} + +/* +** Make sure virtual table pTab is contained in the pParse->apVirtualLock[] +** array so that an OP_VBegin will get generated for it. Add pTab to the +** array if it is missing. If pTab is already in the array, this routine +** is a no-op. +*/ +void sqlite3VtabMakeWritable(Parse *pParse, Table *pTab){ + Parse *pToplevel = sqlite3ParseToplevel(pParse); + int i, n; + Table **apVtabLock; + + assert( IsVirtual(pTab) ); + for(i=0; i<pToplevel->nVtabLock; i++){ + if( pTab==pToplevel->apVtabLock[i] ) return; + } + n = (pToplevel->nVtabLock+1)*sizeof(pToplevel->apVtabLock[0]); + apVtabLock = sqlite3_realloc(pToplevel->apVtabLock, n); + if( apVtabLock ){ + pToplevel->apVtabLock = apVtabLock; + pToplevel->apVtabLock[pToplevel->nVtabLock++] = pTab; + }else{ + pToplevel->db->mallocFailed = 1; + } +} + +/* +** Return the ON CONFLICT resolution mode in effect for the virtual +** table update operation currently in progress. +** +** The results of this routine are undefined unless it is called from +** within an xUpdate method. +*/ +int sqlite3_vtab_on_conflict(sqlite3 *db){ + static const unsigned char aMap[] = { + SQLITE_ROLLBACK, SQLITE_ABORT, SQLITE_FAIL, SQLITE_IGNORE, SQLITE_REPLACE + }; + assert( OE_Rollback==1 && OE_Abort==2 && OE_Fail==3 ); + assert( OE_Ignore==4 && OE_Replace==5 ); + assert( db->vtabOnConflict>=1 && db->vtabOnConflict<=5 ); + return (int)aMap[db->vtabOnConflict-1]; +} + +/* +** Call from within the xCreate() or xConnect() methods to provide +** the SQLite core with additional information about the behavior +** of the virtual table being implemented. +*/ +int sqlite3_vtab_config(sqlite3 *db, int op, ...){ + va_list ap; + int rc = SQLITE_OK; + + sqlite3_mutex_enter(db->mutex); + + va_start(ap, op); + switch( op ){ + case SQLITE_VTAB_CONSTRAINT_SUPPORT: { + VtabCtx *p = db->pVtabCtx; + if( !p ){ + rc = SQLITE_MISUSE_BKPT; + }else{ + assert( p->pTab==0 || (p->pTab->tabFlags & TF_Virtual)!=0 ); + p->pVTable->bConstraint = (u8)va_arg(ap, int); + } + break; + } + default: + rc = SQLITE_MISUSE_BKPT; + break; + } + va_end(ap); + + if( rc!=SQLITE_OK ) sqlite3Error(db, rc, 0); + sqlite3_mutex_leave(db->mutex); + return rc; +} + +#endif /* SQLITE_OMIT_VIRTUALTABLE */ |