/* ** Drop a trigger given a pointer to that trigger. */ void sqlite3DropTriggerPtr(Parse *pParse, Trigger *pTrigger){ Table *pTable; Vdbe *v; sqlite3 *db = pParse->db; int iDb; iDb = sqlite3SchemaToIndex(pParse->db, pTrigger->pSchema); assert( iDb>=0 && iDb<db->nDb ); pTable = tableOfTrigger(pTrigger); assert( pTable ); assert( pTable->pSchema==pTrigger->pSchema || iDb==1 ); #ifndef SQLITE_OMIT_AUTHORIZATION { int code = SQLITE_DROP_TRIGGER; const char *zDb = db->aDb[iDb].zName; const char *zTab = SCHEMA_TABLE(iDb); if( iDb==1 ) code = SQLITE_DROP_TEMP_TRIGGER; if( sqlite3AuthCheck(pParse, code, pTrigger->zName, pTable->zName, zDb) || sqlite3AuthCheck(pParse, SQLITE_DELETE, zTab, 0, zDb) ){ return; } } #endif /* Generate code to destroy the database record of the trigger. */ assert( pTable!=0 ); if( (v = sqlite3GetVdbe(pParse))!=0 ){ int base; static const int iLn = VDBE_OFFSET_LINENO(2); static const VdbeOpList dropTrigger[] = { { OP_Rewind, 0, ADDR(9), 0}, { OP_String8, 0, 1, 0}, /* 1 */ { OP_Column, 0, 1, 2}, { OP_Ne, 2, ADDR(8), 1}, { OP_String8, 0, 1, 0}, /* 4: "trigger" */ { OP_Column, 0, 0, 2}, { OP_Ne, 2, ADDR(8), 1}, { OP_Delete, 0, 0, 0}, { OP_Next, 0, ADDR(1), 0}, /* 8 */ }; sqlite3BeginWriteOperation(pParse, 0, iDb); sqlite3OpenMasterTable(pParse, iDb); base = sqlite3VdbeAddOpList(v, ArraySize(dropTrigger), dropTrigger, iLn); sqlite3VdbeChangeP4(v, base+1, pTrigger->zName, P4_TRANSIENT); sqlite3VdbeChangeP4(v, base+4, "trigger", P4_STATIC); sqlite3ChangeCookie(pParse, iDb); sqlite3VdbeAddOp2(v, OP_Close, 0, 0); sqlite3VdbeAddOp4(v, OP_DropTrigger, iDb, 0, 0, pTrigger->zName, 0); if( pParse->nMem<3 ){ pParse->nMem = 3; } } }
/* ** Open a blob handle. */ int sqlite3_blob_open( sqlite3* db, /* The database connection */ const char *zDb, /* The attached database containing the blob */ const char *zTable, /* The table containing the blob */ const char *zColumn, /* The column containing the blob */ sqlite_int64 iRow, /* The row containing the glob */ int flags, /* True -> read/write access, false -> read-only */ sqlite3_blob **ppBlob /* Handle for accessing the blob returned here */ ){ int nAttempt = 0; int iCol; /* Index of zColumn in row-record */ /* This VDBE program seeks a btree cursor to the identified ** db/table/row entry. The reason for using a vdbe program instead ** of writing code to use the b-tree layer directly is that the ** vdbe program will take advantage of the various transaction, ** locking and error handling infrastructure built into the vdbe. ** ** After seeking the cursor, the vdbe executes an OP_ResultRow. ** Code external to the Vdbe then "borrows" the b-tree cursor and ** uses it to implement the blob_read(), blob_write() and ** blob_bytes() functions. ** ** The sqlite3_blob_close() function finalizes the vdbe program, ** which closes the b-tree cursor and (possibly) commits the ** transaction. */ static const int iLn = VDBE_OFFSET_LINENO(4); static const VdbeOpList openBlob[] = { /* {OP_Transaction, 0, 0, 0}, // 0: Inserted separately */ {OP_TableLock, 0, 0, 0}, /* 1: Acquire a read or write lock */ /* One of the following two instructions is replaced by an OP_Noop. */ {OP_OpenRead, 0, 0, 0}, /* 2: Open cursor 0 for reading */ {OP_OpenWrite, 0, 0, 0}, /* 3: Open cursor 0 for read/write */ {OP_Variable, 1, 1, 1}, /* 4: Push the rowid to the stack */ {OP_NotExists, 0, 10, 1}, /* 5: Seek the cursor */ {OP_Column, 0, 0, 1}, /* 6 */ {OP_ResultRow, 1, 0, 0}, /* 7 */ {OP_Goto, 0, 4, 0}, /* 8 */ {OP_Close, 0, 0, 0}, /* 9 */ {OP_Halt, 0, 0, 0}, /* 10 */ }; int rc = SQLITE_OK; char *zErr = 0; Table *pTab; Parse *pParse = 0; Incrblob *pBlob = 0; #ifdef SQLITE_ENABLE_API_ARMOR if( ppBlob==0 ){ return SQLITE_MISUSE_BKPT; } #endif *ppBlob = 0; #ifdef SQLITE_ENABLE_API_ARMOR if( !sqlite3SafetyCheckOk(db) || zTable==0 ){ return SQLITE_MISUSE_BKPT; } #endif flags = !!flags; /* flags = (flags ? 1 : 0); */ sqlite3_mutex_enter(db->mutex); pBlob = (Incrblob *)sqlite3DbMallocZero(db, sizeof(Incrblob)); if( !pBlob ) goto blob_open_out; pParse = sqlite3StackAllocRaw(db, sizeof(*pParse)); if( !pParse ) goto blob_open_out; do { memset(pParse, 0, sizeof(Parse)); pParse->db = db; sqlite3DbFree(db, zErr); zErr = 0; sqlite3BtreeEnterAll(db); pTab = sqlite3LocateTable(pParse, 0, zTable, zDb); if( pTab && IsVirtual(pTab) ){ pTab = 0; sqlite3ErrorMsg(pParse, "cannot open virtual table: %s", zTable); } if( pTab && !HasRowid(pTab) ){ pTab = 0; sqlite3ErrorMsg(pParse, "cannot open table without rowid: %s", zTable); } #ifndef SQLITE_OMIT_VIEW if( pTab && pTab->pSelect ){ pTab = 0; sqlite3ErrorMsg(pParse, "cannot open view: %s", zTable); } #endif if( !pTab ){ if( pParse->zErrMsg ){ sqlite3DbFree(db, zErr); zErr = pParse->zErrMsg; pParse->zErrMsg = 0; } rc = SQLITE_ERROR; sqlite3BtreeLeaveAll(db); goto blob_open_out; } /* Now search pTab for the exact column. */ for(iCol=0; iCol<pTab->nCol; iCol++) { if( sqlite3StrICmp(pTab->aCol[iCol].zName, zColumn)==0 ){ break; } } if( iCol==pTab->nCol ){ sqlite3DbFree(db, zErr); zErr = sqlite3MPrintf(db, "no such column: \"%s\"", zColumn); rc = SQLITE_ERROR; sqlite3BtreeLeaveAll(db); goto blob_open_out; } /* If the value is being opened for writing, check that the ** column is not indexed, and that it is not part of a foreign key. ** It is against the rules to open a column to which either of these ** descriptions applies for writing. */ if( flags ){ const char *zFault = 0; SIndex *pIdx; #ifndef SQLITE_OMIT_FOREIGN_KEY if( db->flags&SQLITE_ForeignKeys ){ /* Check that the column is not part of an FK child key definition. It ** is not necessary to check if it is part of a parent key, as parent ** key columns must be indexed. The check below will pick up this ** case. */ FKey *pFKey; for(pFKey=pTab->pFKey; pFKey; pFKey=pFKey->pNextFrom){ int j; for(j=0; j<pFKey->nCol; j++){ if( pFKey->aCol[j].iFrom==iCol ){ zFault = "foreign key"; } } } } #endif for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){ int j; for(j=0; j<pIdx->nKeyCol; j++){ /* FIXME: Be smarter about indexes that use expressions */ if( pIdx->aiColumn[j]==iCol || pIdx->aiColumn[j]==XN_EXPR ){ zFault = "indexed"; } } } if( zFault ){ sqlite3DbFree(db, zErr); zErr = sqlite3MPrintf(db, "cannot open %s column for writing", zFault); rc = SQLITE_ERROR; sqlite3BtreeLeaveAll(db); goto blob_open_out; } } pBlob->pStmt = (sqlite3_stmt *)sqlite3VdbeCreate(pParse); assert( pBlob->pStmt || db->mallocFailed ); if( pBlob->pStmt ){ Vdbe *v = (Vdbe *)pBlob->pStmt; int iDb = sqlite3SchemaToIndex(db, pTab->pSchema); sqlite3VdbeAddOp4Int(v, OP_Transaction, iDb, flags, pTab->pSchema->schema_cookie, pTab->pSchema->iGeneration); sqlite3VdbeChangeP5(v, 1); sqlite3VdbeAddOpList(v, ArraySize(openBlob), openBlob, iLn); /* Make sure a mutex is held on the table to be accessed */ sqlite3VdbeUsesBtree(v, iDb); /* Configure the OP_TableLock instruction */ #ifdef SQLITE_OMIT_SHARED_CACHE sqlite3VdbeChangeToNoop(v, 1); #else sqlite3VdbeChangeP1(v, 1, iDb); sqlite3VdbeChangeP2(v, 1, pTab->tnum); sqlite3VdbeChangeP3(v, 1, flags); sqlite3VdbeChangeP4(v, 1, pTab->zName, P4_TRANSIENT); #endif /* Remove either the OP_OpenWrite or OpenRead. Set the P2 ** parameter of the other to pTab->tnum. */ sqlite3VdbeChangeToNoop(v, 3 - flags); sqlite3VdbeChangeP2(v, 2 + flags, pTab->tnum); sqlite3VdbeChangeP3(v, 2 + flags, iDb); /* Configure the number of columns. Configure the cursor to ** think that the table has one more column than it really ** does. An OP_Column to retrieve this imaginary column will ** always return an SQL NULL. This is useful because it means ** we can invoke OP_Column to fill in the vdbe cursors type ** and offset cache without causing any IO. */ sqlite3VdbeChangeP4(v, 2+flags, SQLITE_INT_TO_PTR(pTab->nCol+1),P4_INT32); sqlite3VdbeChangeP2(v, 6, pTab->nCol); if( !db->mallocFailed ){ pParse->nVar = 1; pParse->nMem = 1; pParse->nTab = 1; sqlite3VdbeMakeReady(v, pParse); } } pBlob->flags = flags; pBlob->iCol = iCol; pBlob->db = db; sqlite3BtreeLeaveAll(db); if( db->mallocFailed ){ goto blob_open_out; } sqlite3_bind_int64(pBlob->pStmt, 1, iRow); rc = blobSeekToRow(pBlob, iRow, &zErr); } while( (++nAttempt)<SQLITE_MAX_SCHEMA_RETRY && rc==SQLITE_SCHEMA ); blob_open_out: if( rc==SQLITE_OK && db->mallocFailed==0 ){ *ppBlob = (sqlite3_blob *)pBlob; }else{ if( pBlob && pBlob->pStmt ) sqlite3VdbeFinalize((Vdbe *)pBlob->pStmt); sqlite3DbFree(db, pBlob); } sqlite3ErrorWithMsg(db, rc, (zErr ? "%s" : 0), zErr); sqlite3DbFree(db, zErr); sqlite3ParserReset(pParse); sqlite3StackFree(db, pParse); rc = sqlite3ApiExit(db, rc); sqlite3_mutex_leave(db->mutex); return rc; }