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Diffstat (limited to 'src/libs/sqlite2/trigger.c')
| -rw-r--r-- | src/libs/sqlite2/trigger.c | 764 |
1 files changed, 764 insertions, 0 deletions
diff --git a/src/libs/sqlite2/trigger.c b/src/libs/sqlite2/trigger.c new file mode 100644 index 00000000..8442bb5d --- /dev/null +++ b/src/libs/sqlite2/trigger.c @@ -0,0 +1,764 @@ +/* +** +** 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. +** +************************************************************************* +* +*/ +#include "sqliteInt.h" + +/* +** Delete a linked list of TriggerStep structures. +*/ +void sqliteDeleteTriggerStep(TriggerStep *pTriggerStep){ + while( pTriggerStep ){ + TriggerStep * pTmp = pTriggerStep; + pTriggerStep = pTriggerStep->pNext; + + if( pTmp->target.dyn ) sqliteFree((char*)pTmp->target.z); + sqliteExprDelete(pTmp->pWhere); + sqliteExprListDelete(pTmp->pExprList); + sqliteSelectDelete(pTmp->pSelect); + sqliteIdListDelete(pTmp->pIdList); + + sqliteFree(pTmp); + } +} + +/* +** This is called by the parser when it sees a CREATE TRIGGER statement +** up to the point of the BEGIN before the trigger actions. A Trigger +** structure is generated based on the information available and stored +** in pParse->pNewTrigger. After the trigger actions have been parsed, the +** sqliteFinishTrigger() function is called to complete the trigger +** construction process. +*/ +void sqliteBeginTrigger( + Parse *pParse, /* The parse context of the CREATE TRIGGER statement */ + Token *pName, /* The name of the trigger */ + int tr_tm, /* One of TK_BEFORE, TK_AFTER, TK_INSTEAD */ + int op, /* One of TK_INSERT, TK_UPDATE, TK_DELETE */ + IdList *pColumns, /* column list if this is an UPDATE OF trigger */ + SrcList *pTableName,/* The name of the table/view the trigger applies to */ + int foreach, /* One of TK_ROW or TK_STATEMENT */ + Expr *pWhen, /* WHEN clause */ + int isTemp /* True if the TEMPORARY keyword is present */ +){ + Trigger *nt; + Table *tab; + char *zName = 0; /* Name of the trigger */ + sqlite *db = pParse->db; + int iDb; /* When database to store the trigger in */ + DbFixer sFix; + + /* Check that: + ** 1. the trigger name does not already exist. + ** 2. the table (or view) does exist in the same database as the trigger. + ** 3. that we are not trying to create a trigger on the sqlite_master table + ** 4. That we are not trying to create an INSTEAD OF trigger on a table. + ** 5. That we are not trying to create a BEFORE or AFTER trigger on a view. + */ + if( sqlite_malloc_failed ) goto trigger_cleanup; + assert( pTableName->nSrc==1 ); + if( db->init.busy + && sqliteFixInit(&sFix, pParse, db->init.iDb, "trigger", pName) + && sqliteFixSrcList(&sFix, pTableName) + ){ + goto trigger_cleanup; + } + tab = sqliteSrcListLookup(pParse, pTableName); + if( !tab ){ + goto trigger_cleanup; + } + iDb = isTemp ? 1 : tab->iDb; + if( iDb>=2 && !db->init.busy ){ + sqliteErrorMsg(pParse, "triggers may not be added to auxiliary " + "database %s", db->aDb[tab->iDb].zName); + goto trigger_cleanup; + } + + zName = sqliteStrNDup(pName->z, pName->n); + sqliteDequote(zName); + if( sqliteHashFind(&(db->aDb[iDb].trigHash), zName,pName->n+1) ){ + sqliteErrorMsg(pParse, "trigger %T already exists", pName); + goto trigger_cleanup; + } + if( sqliteStrNICmp(tab->zName, "sqlite_", 7)==0 ){ + sqliteErrorMsg(pParse, "cannot create trigger on system table"); + pParse->nErr++; + goto trigger_cleanup; + } + if( tab->pSelect && tr_tm != TK_INSTEAD ){ + sqliteErrorMsg(pParse, "cannot create %s trigger on view: %S", + (tr_tm == TK_BEFORE)?"BEFORE":"AFTER", pTableName, 0); + goto trigger_cleanup; + } + if( !tab->pSelect && tr_tm == TK_INSTEAD ){ + sqliteErrorMsg(pParse, "cannot create INSTEAD OF" + " trigger on table: %S", pTableName, 0); + goto trigger_cleanup; + } +#ifndef SQLITE_OMIT_AUTHORIZATION + { + int code = SQLITE_CREATE_TRIGGER; + const char *zDb = db->aDb[tab->iDb].zName; + const char *zDbTrig = isTemp ? db->aDb[1].zName : zDb; + if( tab->iDb==1 || isTemp ) code = SQLITE_CREATE_TEMP_TRIGGER; + if( sqliteAuthCheck(pParse, code, zName, tab->zName, zDbTrig) ){ + goto trigger_cleanup; + } + if( sqliteAuthCheck(pParse, SQLITE_INSERT, SCHEMA_TABLE(tab->iDb), 0, zDb)){ + goto trigger_cleanup; + } + } +#endif + + /* INSTEAD OF triggers can only appear on views and BEGIN triggers + ** cannot appear on views. So we might as well translate every + ** INSTEAD OF trigger into a BEFORE trigger. It simplifies code + ** elsewhere. + */ + if (tr_tm == TK_INSTEAD){ + tr_tm = TK_BEFORE; + } + + /* Build the Trigger object */ + nt = (Trigger*)sqliteMalloc(sizeof(Trigger)); + if( nt==0 ) goto trigger_cleanup; + nt->name = zName; + zName = 0; + nt->table = sqliteStrDup(pTableName->a[0].zName); + if( sqlite_malloc_failed ) goto trigger_cleanup; + nt->iDb = iDb; + nt->iTabDb = tab->iDb; + nt->op = op; + nt->tr_tm = tr_tm; + nt->pWhen = sqliteExprDup(pWhen); + nt->pColumns = sqliteIdListDup(pColumns); + nt->foreach = foreach; + sqliteTokenCopy(&nt->nameToken,pName); + assert( pParse->pNewTrigger==0 ); + pParse->pNewTrigger = nt; + +trigger_cleanup: + sqliteFree(zName); + sqliteSrcListDelete(pTableName); + sqliteIdListDelete(pColumns); + sqliteExprDelete(pWhen); +} + +/* +** This routine is called after all of the trigger actions have been parsed +** in order to complete the process of building the trigger. +*/ +void sqliteFinishTrigger( + Parse *pParse, /* Parser context */ + TriggerStep *pStepList, /* The triggered program */ + Token *pAll /* Token that describes the complete CREATE TRIGGER */ +){ + Trigger *nt = 0; /* The trigger whose construction is finishing up */ + sqlite *db = pParse->db; /* The database */ + DbFixer sFix; + + if( pParse->nErr || pParse->pNewTrigger==0 ) goto triggerfinish_cleanup; + nt = pParse->pNewTrigger; + pParse->pNewTrigger = 0; + nt->step_list = pStepList; + while( pStepList ){ + pStepList->pTrig = nt; + pStepList = pStepList->pNext; + } + if( sqliteFixInit(&sFix, pParse, nt->iDb, "trigger", &nt->nameToken) + && sqliteFixTriggerStep(&sFix, nt->step_list) ){ + goto triggerfinish_cleanup; + } + + /* if we are not initializing, and this trigger is not on a TEMP table, + ** build the sqlite_master entry + */ + if( !db->init.busy ){ + static VdbeOpList insertTrig[] = { + { OP_NewRecno, 0, 0, 0 }, + { OP_String, 0, 0, "trigger" }, + { OP_String, 0, 0, 0 }, /* 2: trigger name */ + { OP_String, 0, 0, 0 }, /* 3: table name */ + { OP_Integer, 0, 0, 0 }, + { OP_String, 0, 0, 0 }, /* 5: SQL */ + { OP_MakeRecord, 5, 0, 0 }, + { OP_PutIntKey, 0, 0, 0 }, + }; + int addr; + Vdbe *v; + + /* Make an entry in the sqlite_master table */ + v = sqliteGetVdbe(pParse); + if( v==0 ) goto triggerfinish_cleanup; + sqliteBeginWriteOperation(pParse, 0, 0); + sqliteOpenMasterTable(v, nt->iDb); + addr = sqliteVdbeAddOpList(v, ArraySize(insertTrig), insertTrig); + sqliteVdbeChangeP3(v, addr+2, nt->name, 0); + sqliteVdbeChangeP3(v, addr+3, nt->table, 0); + sqliteVdbeChangeP3(v, addr+5, pAll->z, pAll->n); + if( nt->iDb==0 ){ + sqliteChangeCookie(db, v); + } + sqliteVdbeAddOp(v, OP_Close, 0, 0); + sqliteEndWriteOperation(pParse); + } + + if( !pParse->explain ){ + Table *pTab; + sqliteHashInsert(&db->aDb[nt->iDb].trigHash, + nt->name, strlen(nt->name)+1, nt); + pTab = sqliteLocateTable(pParse, nt->table, db->aDb[nt->iTabDb].zName); + assert( pTab!=0 ); + nt->pNext = pTab->pTrigger; + pTab->pTrigger = nt; + nt = 0; + } + +triggerfinish_cleanup: + sqliteDeleteTrigger(nt); + sqliteDeleteTrigger(pParse->pNewTrigger); + pParse->pNewTrigger = 0; + sqliteDeleteTriggerStep(pStepList); +} + +/* +** Make a copy of all components of the given trigger step. This has +** the effect of copying all Expr.token.z values into memory obtained +** from sqliteMalloc(). As initially created, the Expr.token.z values +** all point to the input string that was fed to the parser. But that +** string is ephemeral - it will go away as soon as the sqlite_exec() +** call that started the parser exits. This routine makes a persistent +** copy of all the Expr.token.z strings so that the TriggerStep structure +** will be valid even after the sqlite_exec() call returns. +*/ +static void sqlitePersistTriggerStep(TriggerStep *p){ + if( p->target.z ){ + p->target.z = sqliteStrNDup(p->target.z, p->target.n); + p->target.dyn = 1; + } + if( p->pSelect ){ + Select *pNew = sqliteSelectDup(p->pSelect); + sqliteSelectDelete(p->pSelect); + p->pSelect = pNew; + } + if( p->pWhere ){ + Expr *pNew = sqliteExprDup(p->pWhere); + sqliteExprDelete(p->pWhere); + p->pWhere = pNew; + } + if( p->pExprList ){ + ExprList *pNew = sqliteExprListDup(p->pExprList); + sqliteExprListDelete(p->pExprList); + p->pExprList = pNew; + } + if( p->pIdList ){ + IdList *pNew = sqliteIdListDup(p->pIdList); + sqliteIdListDelete(p->pIdList); + p->pIdList = pNew; + } +} + +/* +** Turn a SELECT statement (that the pSelect parameter points to) into +** a trigger step. Return a pointer to a TriggerStep structure. +** +** The parser calls this routine when it finds a SELECT statement in +** body of a TRIGGER. +*/ +TriggerStep *sqliteTriggerSelectStep(Select *pSelect){ + TriggerStep *pTriggerStep = sqliteMalloc(sizeof(TriggerStep)); + if( pTriggerStep==0 ) return 0; + + pTriggerStep->op = TK_SELECT; + pTriggerStep->pSelect = pSelect; + pTriggerStep->orconf = OE_Default; + sqlitePersistTriggerStep(pTriggerStep); + + return pTriggerStep; +} + +/* +** Build a trigger step out of an INSERT statement. Return a pointer +** to the new trigger step. +** +** The parser calls this routine when it sees an INSERT inside the +** body of a trigger. +*/ +TriggerStep *sqliteTriggerInsertStep( + Token *pTableName, /* Name of the table into which we insert */ + IdList *pColumn, /* List of columns in pTableName to insert into */ + ExprList *pEList, /* The VALUE clause: a list of values to be inserted */ + Select *pSelect, /* A SELECT statement that supplies values */ + int orconf /* The conflict algorithm (OE_Abort, OE_Replace, etc.) */ +){ + TriggerStep *pTriggerStep = sqliteMalloc(sizeof(TriggerStep)); + if( pTriggerStep==0 ) return 0; + + assert(pEList == 0 || pSelect == 0); + assert(pEList != 0 || pSelect != 0); + + pTriggerStep->op = TK_INSERT; + pTriggerStep->pSelect = pSelect; + pTriggerStep->target = *pTableName; + pTriggerStep->pIdList = pColumn; + pTriggerStep->pExprList = pEList; + pTriggerStep->orconf = orconf; + sqlitePersistTriggerStep(pTriggerStep); + + return pTriggerStep; +} + +/* +** Construct a trigger step that implements an UPDATE statement and return +** a pointer to that trigger step. The parser calls this routine when it +** sees an UPDATE statement inside the body of a CREATE TRIGGER. +*/ +TriggerStep *sqliteTriggerUpdateStep( + Token *pTableName, /* Name of the table to be updated */ + ExprList *pEList, /* The SET clause: list of column and new values */ + Expr *pWhere, /* The WHERE clause */ + int orconf /* The conflict algorithm. (OE_Abort, OE_Ignore, etc) */ +){ + TriggerStep *pTriggerStep = sqliteMalloc(sizeof(TriggerStep)); + if( pTriggerStep==0 ) return 0; + + pTriggerStep->op = TK_UPDATE; + pTriggerStep->target = *pTableName; + pTriggerStep->pExprList = pEList; + pTriggerStep->pWhere = pWhere; + pTriggerStep->orconf = orconf; + sqlitePersistTriggerStep(pTriggerStep); + + return pTriggerStep; +} + +/* +** Construct a trigger step that implements a DELETE statement and return +** a pointer to that trigger step. The parser calls this routine when it +** sees a DELETE statement inside the body of a CREATE TRIGGER. +*/ +TriggerStep *sqliteTriggerDeleteStep(Token *pTableName, Expr *pWhere){ + TriggerStep *pTriggerStep = sqliteMalloc(sizeof(TriggerStep)); + if( pTriggerStep==0 ) return 0; + + pTriggerStep->op = TK_DELETE; + pTriggerStep->target = *pTableName; + pTriggerStep->pWhere = pWhere; + pTriggerStep->orconf = OE_Default; + sqlitePersistTriggerStep(pTriggerStep); + + return pTriggerStep; +} + +/* +** Recursively delete a Trigger structure +*/ +void sqliteDeleteTrigger(Trigger *pTrigger){ + if( pTrigger==0 ) return; + sqliteDeleteTriggerStep(pTrigger->step_list); + sqliteFree(pTrigger->name); + sqliteFree(pTrigger->table); + sqliteExprDelete(pTrigger->pWhen); + sqliteIdListDelete(pTrigger->pColumns); + if( pTrigger->nameToken.dyn ) sqliteFree((char*)pTrigger->nameToken.z); + sqliteFree(pTrigger); +} + +/* + * This function is called to drop a trigger from the database schema. + * + * This may be called directly from the parser and therefore identifies + * the trigger by name. The sqliteDropTriggerPtr() routine does the + * same job as this routine except it take a spointer to the trigger + * instead of the trigger name. + * + * Note that this function does not delete the trigger entirely. Instead it + * removes it from the internal schema and places it in the trigDrop hash + * table. This is so that the trigger can be restored into the database schema + * if the transaction is rolled back. + */ +void sqliteDropTrigger(Parse *pParse, SrcList *pName){ + Trigger *pTrigger; + int i; + const char *zDb; + const char *zName; + int nName; + sqlite *db = pParse->db; + + if( sqlite_malloc_failed ) goto drop_trigger_cleanup; + assert( pName->nSrc==1 ); + zDb = pName->a[0].zDatabase; + zName = pName->a[0].zName; + nName = strlen(zName); + for(i=0; i<db->nDb; i++){ + int j = (i<2) ? i^1 : i; /* Search TEMP before MAIN */ + if( zDb && sqliteStrICmp(db->aDb[j].zName, zDb) ) continue; + pTrigger = sqliteHashFind(&(db->aDb[j].trigHash), zName, nName+1); + if( pTrigger ) break; + } + if( !pTrigger ){ + sqliteErrorMsg(pParse, "no such trigger: %S", pName, 0); + goto drop_trigger_cleanup; + } + sqliteDropTriggerPtr(pParse, pTrigger, 0); + +drop_trigger_cleanup: + sqliteSrcListDelete(pName); +} + +/* +** Drop a trigger given a pointer to that trigger. If nested is false, +** then also generate code to remove the trigger from the SQLITE_MASTER +** table. +*/ +void sqliteDropTriggerPtr(Parse *pParse, Trigger *pTrigger, int nested){ + Table *pTable; + Vdbe *v; + sqlite *db = pParse->db; + + assert( pTrigger->iDb<db->nDb ); + if( pTrigger->iDb>=2 ){ + sqliteErrorMsg(pParse, "triggers may not be removed from " + "auxiliary database %s", db->aDb[pTrigger->iDb].zName); + return; + } + pTable = sqliteFindTable(db, pTrigger->table,db->aDb[pTrigger->iTabDb].zName); + assert(pTable); + assert( pTable->iDb==pTrigger->iDb || pTrigger->iDb==1 ); +#ifndef SQLITE_OMIT_AUTHORIZATION + { + int code = SQLITE_DROP_TRIGGER; + const char *zDb = db->aDb[pTrigger->iDb].zName; + const char *zTab = SCHEMA_TABLE(pTrigger->iDb); + if( pTrigger->iDb ) code = SQLITE_DROP_TEMP_TRIGGER; + if( sqliteAuthCheck(pParse, code, pTrigger->name, pTable->zName, zDb) || + sqliteAuthCheck(pParse, SQLITE_DELETE, zTab, 0, zDb) ){ + return; + } + } +#endif + + /* Generate code to destroy the database record of the trigger. + */ + if( pTable!=0 && !nested && (v = sqliteGetVdbe(pParse))!=0 ){ + int base; + static VdbeOpList dropTrigger[] = { + { OP_Rewind, 0, ADDR(9), 0}, + { OP_String, 0, 0, 0}, /* 1 */ + { OP_Column, 0, 1, 0}, + { OP_Ne, 0, ADDR(8), 0}, + { OP_String, 0, 0, "trigger"}, + { OP_Column, 0, 0, 0}, + { OP_Ne, 0, ADDR(8), 0}, + { OP_Delete, 0, 0, 0}, + { OP_Next, 0, ADDR(1), 0}, /* 8 */ + }; + + sqliteBeginWriteOperation(pParse, 0, 0); + sqliteOpenMasterTable(v, pTrigger->iDb); + base = sqliteVdbeAddOpList(v, ArraySize(dropTrigger), dropTrigger); + sqliteVdbeChangeP3(v, base+1, pTrigger->name, 0); + if( pTrigger->iDb==0 ){ + sqliteChangeCookie(db, v); + } + sqliteVdbeAddOp(v, OP_Close, 0, 0); + sqliteEndWriteOperation(pParse); + } + + /* + * If this is not an "explain", then delete the trigger structure. + */ + if( !pParse->explain ){ + const char *zName = pTrigger->name; + int nName = strlen(zName); + if( pTable->pTrigger == pTrigger ){ + pTable->pTrigger = pTrigger->pNext; + }else{ + Trigger *cc = pTable->pTrigger; + while( cc ){ + if( cc->pNext == pTrigger ){ + cc->pNext = cc->pNext->pNext; + break; + } + cc = cc->pNext; + } + assert(cc); + } + sqliteHashInsert(&(db->aDb[pTrigger->iDb].trigHash), zName, nName+1, 0); + sqliteDeleteTrigger(pTrigger); + } +} + +/* +** pEList is the SET clause of an UPDATE statement. Each entry +** in pEList is of the format <id>=<expr>. If any of the entries +** in pEList have an <id> which matches an identifier in pIdList, +** then return TRUE. If pIdList==NULL, then it is considered a +** wildcard that matches anything. Likewise if pEList==NULL then +** it matches anything so always return true. Return false only +** if there is no match. +*/ +static int checkColumnOverLap(IdList *pIdList, ExprList *pEList){ + int e; + if( !pIdList || !pEList ) return 1; + for(e=0; e<pEList->nExpr; e++){ + if( sqliteIdListIndex(pIdList, pEList->a[e].zName)>=0 ) return 1; + } + return 0; +} + +/* A global variable that is TRUE if we should always set up temp tables for + * for triggers, even if there are no triggers to code. This is used to test + * how much overhead the triggers algorithm is causing. + * + * This flag can be set or cleared using the "trigger_overhead_test" pragma. + * The pragma is not documented since it is not really part of the interface + * to SQLite, just the test procedure. +*/ +int always_code_trigger_setup = 0; + +/* + * Returns true if a trigger matching op, tr_tm and foreach that is NOT already + * on the Parse objects trigger-stack (to prevent recursive trigger firing) is + * found in the list specified as pTrigger. + */ +int sqliteTriggersExist( + Parse *pParse, /* Used to check for recursive triggers */ + Trigger *pTrigger, /* A list of triggers associated with a table */ + int op, /* one of TK_DELETE, TK_INSERT, TK_UPDATE */ + int tr_tm, /* one of TK_BEFORE, TK_AFTER */ + int foreach, /* one of TK_ROW or TK_STATEMENT */ + ExprList *pChanges /* Columns that change in an UPDATE statement */ +){ + Trigger * pTriggerCursor; + + if( always_code_trigger_setup ){ + return 1; + } + + pTriggerCursor = pTrigger; + while( pTriggerCursor ){ + if( pTriggerCursor->op == op && + pTriggerCursor->tr_tm == tr_tm && + pTriggerCursor->foreach == foreach && + checkColumnOverLap(pTriggerCursor->pColumns, pChanges) ){ + TriggerStack * ss; + ss = pParse->trigStack; + while( ss && ss->pTrigger != pTrigger ){ + ss = ss->pNext; + } + if( !ss )return 1; + } + pTriggerCursor = pTriggerCursor->pNext; + } + + return 0; +} + +/* +** Convert the pStep->target token into a SrcList and return a pointer +** to that SrcList. +** +** This routine adds a specific database name, if needed, to the target when +** forming the SrcList. This prevents a trigger in one database from +** referring to a target in another database. An exception is when the +** trigger is in TEMP in which case it can refer to any other database it +** wants. +*/ +static SrcList *targetSrcList( + Parse *pParse, /* The parsing context */ + TriggerStep *pStep /* The trigger containing the target token */ +){ + Token sDb; /* Dummy database name token */ + int iDb; /* Index of the database to use */ + SrcList *pSrc; /* SrcList to be returned */ + + iDb = pStep->pTrig->iDb; + if( iDb==0 || iDb>=2 ){ + assert( iDb<pParse->db->nDb ); + sDb.z = pParse->db->aDb[iDb].zName; + sDb.n = strlen(sDb.z); + pSrc = sqliteSrcListAppend(0, &sDb, &pStep->target); + } else { + pSrc = sqliteSrcListAppend(0, &pStep->target, 0); + } + return pSrc; +} + +/* +** Generate VDBE code for zero or more statements inside the body of a +** trigger. +*/ +static int codeTriggerProgram( + Parse *pParse, /* The parser context */ + TriggerStep *pStepList, /* List of statements inside the trigger body */ + int orconfin /* Conflict algorithm. (OE_Abort, etc) */ +){ + TriggerStep * pTriggerStep = pStepList; + int orconf; + + while( pTriggerStep ){ + int saveNTab = pParse->nTab; + + orconf = (orconfin == OE_Default)?pTriggerStep->orconf:orconfin; + pParse->trigStack->orconf = orconf; + switch( pTriggerStep->op ){ + case TK_SELECT: { + Select * ss = sqliteSelectDup(pTriggerStep->pSelect); + assert(ss); + assert(ss->pSrc); + sqliteSelect(pParse, ss, SRT_Discard, 0, 0, 0, 0); + sqliteSelectDelete(ss); + break; + } + case TK_UPDATE: { + SrcList *pSrc; + pSrc = targetSrcList(pParse, pTriggerStep); + sqliteVdbeAddOp(pParse->pVdbe, OP_ListPush, 0, 0); + sqliteUpdate(pParse, pSrc, + sqliteExprListDup(pTriggerStep->pExprList), + sqliteExprDup(pTriggerStep->pWhere), orconf); + sqliteVdbeAddOp(pParse->pVdbe, OP_ListPop, 0, 0); + break; + } + case TK_INSERT: { + SrcList *pSrc; + pSrc = targetSrcList(pParse, pTriggerStep); + sqliteInsert(pParse, pSrc, + sqliteExprListDup(pTriggerStep->pExprList), + sqliteSelectDup(pTriggerStep->pSelect), + sqliteIdListDup(pTriggerStep->pIdList), orconf); + break; + } + case TK_DELETE: { + SrcList *pSrc; + sqliteVdbeAddOp(pParse->pVdbe, OP_ListPush, 0, 0); + pSrc = targetSrcList(pParse, pTriggerStep); + sqliteDeleteFrom(pParse, pSrc, sqliteExprDup(pTriggerStep->pWhere)); + sqliteVdbeAddOp(pParse->pVdbe, OP_ListPop, 0, 0); + break; + } + default: + assert(0); + } + pParse->nTab = saveNTab; + pTriggerStep = pTriggerStep->pNext; + } + + return 0; +} + +/* +** This is called to code FOR EACH ROW triggers. +** +** When the code that this function generates is executed, the following +** must be true: +** +** 1. No cursors may be open in the main database. (But newIdx and oldIdx +** can be indices of cursors in temporary tables. See below.) +** +** 2. If the triggers being coded are ON INSERT or ON UPDATE triggers, then +** a temporary vdbe cursor (index newIdx) must be open and pointing at +** a row containing values to be substituted for new.* expressions in the +** trigger program(s). +** +** 3. If the triggers being coded are ON DELETE or ON UPDATE triggers, then +** a temporary vdbe cursor (index oldIdx) must be open and pointing at +** a row containing values to be substituted for old.* expressions in the +** trigger program(s). +** +*/ +int sqliteCodeRowTrigger( + Parse *pParse, /* Parse context */ + int op, /* One of TK_UPDATE, TK_INSERT, TK_DELETE */ + ExprList *pChanges, /* Changes list for any UPDATE OF triggers */ + int tr_tm, /* One of TK_BEFORE, TK_AFTER */ + Table *pTab, /* The table to code triggers from */ + int newIdx, /* The indice of the "new" row to access */ + int oldIdx, /* The indice of the "old" row to access */ + int orconf, /* ON CONFLICT policy */ + int ignoreJump /* Instruction to jump to for RAISE(IGNORE) */ +){ + Trigger * pTrigger; + TriggerStack * pTriggerStack; + + assert(op == TK_UPDATE || op == TK_INSERT || op == TK_DELETE); + assert(tr_tm == TK_BEFORE || tr_tm == TK_AFTER ); + + assert(newIdx != -1 || oldIdx != -1); + + pTrigger = pTab->pTrigger; + while( pTrigger ){ + int fire_this = 0; + + /* determine whether we should code this trigger */ + if( pTrigger->op == op && pTrigger->tr_tm == tr_tm && + pTrigger->foreach == TK_ROW ){ + fire_this = 1; + pTriggerStack = pParse->trigStack; + while( pTriggerStack ){ + if( pTriggerStack->pTrigger == pTrigger ){ + fire_this = 0; + } + pTriggerStack = pTriggerStack->pNext; + } + if( op == TK_UPDATE && pTrigger->pColumns && + !checkColumnOverLap(pTrigger->pColumns, pChanges) ){ + fire_this = 0; + } + } + + if( fire_this && (pTriggerStack = sqliteMalloc(sizeof(TriggerStack)))!=0 ){ + int endTrigger; + SrcList dummyTablist; + Expr * whenExpr; + AuthContext sContext; + + dummyTablist.nSrc = 0; + + /* Push an entry on to the trigger stack */ + pTriggerStack->pTrigger = pTrigger; + pTriggerStack->newIdx = newIdx; + pTriggerStack->oldIdx = oldIdx; + pTriggerStack->pTab = pTab; + pTriggerStack->pNext = pParse->trigStack; + pTriggerStack->ignoreJump = ignoreJump; + pParse->trigStack = pTriggerStack; + sqliteAuthContextPush(pParse, &sContext, pTrigger->name); + + /* code the WHEN clause */ + endTrigger = sqliteVdbeMakeLabel(pParse->pVdbe); + whenExpr = sqliteExprDup(pTrigger->pWhen); + if( sqliteExprResolveIds(pParse, &dummyTablist, 0, whenExpr) ){ + pParse->trigStack = pParse->trigStack->pNext; + sqliteFree(pTriggerStack); + sqliteExprDelete(whenExpr); + return 1; + } + sqliteExprIfFalse(pParse, whenExpr, endTrigger, 1); + sqliteExprDelete(whenExpr); + + sqliteVdbeAddOp(pParse->pVdbe, OP_ContextPush, 0, 0); + codeTriggerProgram(pParse, pTrigger->step_list, orconf); + sqliteVdbeAddOp(pParse->pVdbe, OP_ContextPop, 0, 0); + + /* Pop the entry off the trigger stack */ + pParse->trigStack = pParse->trigStack->pNext; + sqliteAuthContextPop(&sContext); + sqliteFree(pTriggerStack); + + sqliteVdbeResolveLabel(pParse->pVdbe, endTrigger); + } + pTrigger = pTrigger->pNext; + } + + return 0; +} |