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Diffstat (limited to '')
| -rw-r--r-- | src/trigger.c | 1490 |
1 files changed, 1490 insertions, 0 deletions
diff --git a/src/trigger.c b/src/trigger.c new file mode 100644 index 0000000..97ca249 --- /dev/null +++ b/src/trigger.c @@ -0,0 +1,1490 @@ +/* +** +** 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 the implementation for TRIGGERs +*/ +#include "sqliteInt.h" + +#ifndef SQLITE_OMIT_TRIGGER +/* +** Delete a linked list of TriggerStep structures. +*/ +void sqlite3DeleteTriggerStep(sqlite3 *db, TriggerStep *pTriggerStep){ + while( pTriggerStep ){ + TriggerStep * pTmp = pTriggerStep; + pTriggerStep = pTriggerStep->pNext; + + sqlite3ExprDelete(db, pTmp->pWhere); + sqlite3ExprListDelete(db, pTmp->pExprList); + sqlite3SelectDelete(db, pTmp->pSelect); + sqlite3IdListDelete(db, pTmp->pIdList); + sqlite3UpsertDelete(db, pTmp->pUpsert); + sqlite3SrcListDelete(db, pTmp->pFrom); + sqlite3DbFree(db, pTmp->zSpan); + + sqlite3DbFree(db, pTmp); + } +} + +/* +** Given table pTab, return a list of all the triggers attached to +** the table. The list is connected by Trigger.pNext pointers. +** +** All of the triggers on pTab that are in the same database as pTab +** are already attached to pTab->pTrigger. But there might be additional +** triggers on pTab in the TEMP schema. This routine prepends all +** TEMP triggers on pTab to the beginning of the pTab->pTrigger list +** and returns the combined list. +** +** To state it another way: This routine returns a list of all triggers +** that fire off of pTab. The list will include any TEMP triggers on +** pTab as well as the triggers lised in pTab->pTrigger. +*/ +Trigger *sqlite3TriggerList(Parse *pParse, Table *pTab){ + Schema *pTmpSchema; /* Schema of the pTab table */ + Trigger *pList; /* List of triggers to return */ + HashElem *p; /* Loop variable for TEMP triggers */ + + assert( pParse->disableTriggers==0 ); + pTmpSchema = pParse->db->aDb[1].pSchema; + p = sqliteHashFirst(&pTmpSchema->trigHash); + pList = pTab->pTrigger; + while( p ){ + Trigger *pTrig = (Trigger *)sqliteHashData(p); + if( pTrig->pTabSchema==pTab->pSchema + && pTrig->table + && 0==sqlite3StrICmp(pTrig->table, pTab->zName) + && (pTrig->pTabSchema!=pTmpSchema || pTrig->bReturning) + ){ + pTrig->pNext = pList; + pList = pTrig; + }else if( pTrig->op==TK_RETURNING ){ +#ifndef SQLITE_OMIT_VIRTUALTABLE + assert( pParse->db->pVtabCtx==0 ); +#endif + assert( pParse->bReturning ); + assert( &(pParse->u1.pReturning->retTrig) == pTrig ); + pTrig->table = pTab->zName; + pTrig->pTabSchema = pTab->pSchema; + pTrig->pNext = pList; + pList = pTrig; + } + p = sqliteHashNext(p); + } +#if 0 + if( pList ){ + Trigger *pX; + printf("Triggers for %s:", pTab->zName); + for(pX=pList; pX; pX=pX->pNext){ + printf(" %s", pX->zName); + } + printf("\n"); + fflush(stdout); + } +#endif + return pList; +} + +/* +** 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 +** sqlite3FinishTrigger() function is called to complete the trigger +** construction process. +*/ +void sqlite3BeginTrigger( + Parse *pParse, /* The parse context of the CREATE TRIGGER statement */ + Token *pName1, /* The name of the trigger */ + Token *pName2, /* 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 */ + Expr *pWhen, /* WHEN clause */ + int isTemp, /* True if the TEMPORARY keyword is present */ + int noErr /* Suppress errors if the trigger already exists */ +){ + Trigger *pTrigger = 0; /* The new trigger */ + Table *pTab; /* Table that the trigger fires off of */ + char *zName = 0; /* Name of the trigger */ + sqlite3 *db = pParse->db; /* The database connection */ + int iDb; /* The database to store the trigger in */ + Token *pName; /* The unqualified db name */ + DbFixer sFix; /* State vector for the DB fixer */ + + assert( pName1!=0 ); /* pName1->z might be NULL, but not pName1 itself */ + assert( pName2!=0 ); + assert( op==TK_INSERT || op==TK_UPDATE || op==TK_DELETE ); + assert( op>0 && op<0xff ); + if( isTemp ){ + /* If TEMP was specified, then the trigger name may not be qualified. */ + if( pName2->n>0 ){ + sqlite3ErrorMsg(pParse, "temporary trigger may not have qualified name"); + goto trigger_cleanup; + } + iDb = 1; + pName = pName1; + }else{ + /* Figure out the db that the trigger will be created in */ + iDb = sqlite3TwoPartName(pParse, pName1, pName2, &pName); + if( iDb<0 ){ + goto trigger_cleanup; + } + } + if( !pTableName || db->mallocFailed ){ + goto trigger_cleanup; + } + + /* A long-standing parser bug is that this syntax was allowed: + ** + ** CREATE TRIGGER attached.demo AFTER INSERT ON attached.tab .... + ** ^^^^^^^^ + ** + ** To maintain backwards compatibility, ignore the database + ** name on pTableName if we are reparsing out of the schema table + */ + if( db->init.busy && iDb!=1 ){ + sqlite3DbFree(db, pTableName->a[0].zDatabase); + pTableName->a[0].zDatabase = 0; + } + + /* If the trigger name was unqualified, and the table is a temp table, + ** then set iDb to 1 to create the trigger in the temporary database. + ** If sqlite3SrcListLookup() returns 0, indicating the table does not + ** exist, the error is caught by the block below. + */ + pTab = sqlite3SrcListLookup(pParse, pTableName); + if( db->init.busy==0 && pName2->n==0 && pTab + && pTab->pSchema==db->aDb[1].pSchema ){ + iDb = 1; + } + + /* Ensure the table name matches database name and that the table exists */ + if( db->mallocFailed ) goto trigger_cleanup; + assert( pTableName->nSrc==1 ); + sqlite3FixInit(&sFix, pParse, iDb, "trigger", pName); + if( sqlite3FixSrcList(&sFix, pTableName) ){ + goto trigger_cleanup; + } + pTab = sqlite3SrcListLookup(pParse, pTableName); + if( !pTab ){ + /* The table does not exist. */ + goto trigger_orphan_error; + } + if( IsVirtual(pTab) ){ + sqlite3ErrorMsg(pParse, "cannot create triggers on virtual tables"); + goto trigger_orphan_error; + } + if( (pTab->tabFlags & TF_Shadow)!=0 && sqlite3ReadOnlyShadowTables(db) ){ + sqlite3ErrorMsg(pParse, "cannot create triggers on shadow tables"); + goto trigger_orphan_error; + } + + /* Check that the trigger name is not reserved and that no trigger of the + ** specified name exists */ + zName = sqlite3NameFromToken(db, pName); + if( zName==0 ){ + assert( db->mallocFailed ); + goto trigger_cleanup; + } + if( sqlite3CheckObjectName(pParse, zName, "trigger", pTab->zName) ){ + goto trigger_cleanup; + } + assert( sqlite3SchemaMutexHeld(db, iDb, 0) ); + if( !IN_RENAME_OBJECT ){ + if( sqlite3HashFind(&(db->aDb[iDb].pSchema->trigHash),zName) ){ + if( !noErr ){ + sqlite3ErrorMsg(pParse, "trigger %T already exists", pName); + }else{ + assert( !db->init.busy ); + sqlite3CodeVerifySchema(pParse, iDb); + VVA_ONLY( pParse->ifNotExists = 1; ) + } + goto trigger_cleanup; + } + } + + /* Do not create a trigger on a system table */ + if( sqlite3StrNICmp(pTab->zName, "sqlite_", 7)==0 ){ + sqlite3ErrorMsg(pParse, "cannot create trigger on system table"); + goto trigger_cleanup; + } + + /* INSTEAD of triggers are only for views and views only support INSTEAD + ** of triggers. + */ + if( IsView(pTab) && tr_tm!=TK_INSTEAD ){ + sqlite3ErrorMsg(pParse, "cannot create %s trigger on view: %S", + (tr_tm == TK_BEFORE)?"BEFORE":"AFTER", pTableName->a); + goto trigger_orphan_error; + } + if( !IsView(pTab) && tr_tm==TK_INSTEAD ){ + sqlite3ErrorMsg(pParse, "cannot create INSTEAD OF" + " trigger on table: %S", pTableName->a); + goto trigger_orphan_error; + } + +#ifndef SQLITE_OMIT_AUTHORIZATION + if( !IN_RENAME_OBJECT ){ + int iTabDb = sqlite3SchemaToIndex(db, pTab->pSchema); + int code = SQLITE_CREATE_TRIGGER; + const char *zDb = db->aDb[iTabDb].zDbSName; + const char *zDbTrig = isTemp ? db->aDb[1].zDbSName : zDb; + if( iTabDb==1 || isTemp ) code = SQLITE_CREATE_TEMP_TRIGGER; + if( sqlite3AuthCheck(pParse, code, zName, pTab->zName, zDbTrig) ){ + goto trigger_cleanup; + } + if( sqlite3AuthCheck(pParse, SQLITE_INSERT, SCHEMA_TABLE(iTabDb),0,zDb)){ + goto trigger_cleanup; + } + } +#endif + + /* INSTEAD OF triggers can only appear on views and BEFORE 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 */ + pTrigger = (Trigger*)sqlite3DbMallocZero(db, sizeof(Trigger)); + if( pTrigger==0 ) goto trigger_cleanup; + pTrigger->zName = zName; + zName = 0; + pTrigger->table = sqlite3DbStrDup(db, pTableName->a[0].zName); + pTrigger->pSchema = db->aDb[iDb].pSchema; + pTrigger->pTabSchema = pTab->pSchema; + pTrigger->op = (u8)op; + pTrigger->tr_tm = tr_tm==TK_BEFORE ? TRIGGER_BEFORE : TRIGGER_AFTER; + if( IN_RENAME_OBJECT ){ + sqlite3RenameTokenRemap(pParse, pTrigger->table, pTableName->a[0].zName); + pTrigger->pWhen = pWhen; + pWhen = 0; + }else{ + pTrigger->pWhen = sqlite3ExprDup(db, pWhen, EXPRDUP_REDUCE); + } + pTrigger->pColumns = pColumns; + pColumns = 0; + assert( pParse->pNewTrigger==0 ); + pParse->pNewTrigger = pTrigger; + +trigger_cleanup: + sqlite3DbFree(db, zName); + sqlite3SrcListDelete(db, pTableName); + sqlite3IdListDelete(db, pColumns); + sqlite3ExprDelete(db, pWhen); + if( !pParse->pNewTrigger ){ + sqlite3DeleteTrigger(db, pTrigger); + }else{ + assert( pParse->pNewTrigger==pTrigger ); + } + return; + +trigger_orphan_error: + if( db->init.iDb==1 ){ + /* Ticket #3810. + ** Normally, whenever a table is dropped, all associated triggers are + ** dropped too. But if a TEMP trigger is created on a non-TEMP table + ** and the table is dropped by a different database connection, the + ** trigger is not visible to the database connection that does the + ** drop so the trigger cannot be dropped. This results in an + ** "orphaned trigger" - a trigger whose associated table is missing. + ** + ** 2020-11-05 see also https://sqlite.org/forum/forumpost/157dc791df + */ + db->init.orphanTrigger = 1; + } + goto trigger_cleanup; +} + +/* +** This routine is called after all of the trigger actions have been parsed +** in order to complete the process of building the trigger. +*/ +void sqlite3FinishTrigger( + Parse *pParse, /* Parser context */ + TriggerStep *pStepList, /* The triggered program */ + Token *pAll /* Token that describes the complete CREATE TRIGGER */ +){ + Trigger *pTrig = pParse->pNewTrigger; /* Trigger being finished */ + char *zName; /* Name of trigger */ + sqlite3 *db = pParse->db; /* The database */ + DbFixer sFix; /* Fixer object */ + int iDb; /* Database containing the trigger */ + Token nameToken; /* Trigger name for error reporting */ + + pParse->pNewTrigger = 0; + if( NEVER(pParse->nErr) || !pTrig ) goto triggerfinish_cleanup; + zName = pTrig->zName; + iDb = sqlite3SchemaToIndex(pParse->db, pTrig->pSchema); + pTrig->step_list = pStepList; + while( pStepList ){ + pStepList->pTrig = pTrig; + pStepList = pStepList->pNext; + } + sqlite3TokenInit(&nameToken, pTrig->zName); + sqlite3FixInit(&sFix, pParse, iDb, "trigger", &nameToken); + if( sqlite3FixTriggerStep(&sFix, pTrig->step_list) + || sqlite3FixExpr(&sFix, pTrig->pWhen) + ){ + goto triggerfinish_cleanup; + } + +#ifndef SQLITE_OMIT_ALTERTABLE + if( IN_RENAME_OBJECT ){ + assert( !db->init.busy ); + pParse->pNewTrigger = pTrig; + pTrig = 0; + }else +#endif + + /* if we are not initializing, + ** build the sqlite_schema entry + */ + if( !db->init.busy ){ + Vdbe *v; + char *z; + + /* If this is a new CREATE TABLE statement, and if shadow tables + ** are read-only, and the trigger makes a change to a shadow table, + ** then raise an error - do not allow the trigger to be created. */ + if( sqlite3ReadOnlyShadowTables(db) ){ + TriggerStep *pStep; + for(pStep=pTrig->step_list; pStep; pStep=pStep->pNext){ + if( pStep->zTarget!=0 + && sqlite3ShadowTableName(db, pStep->zTarget) + ){ + sqlite3ErrorMsg(pParse, + "trigger \"%s\" may not write to shadow table \"%s\"", + pTrig->zName, pStep->zTarget); + goto triggerfinish_cleanup; + } + } + } + + /* Make an entry in the sqlite_schema table */ + v = sqlite3GetVdbe(pParse); + if( v==0 ) goto triggerfinish_cleanup; + sqlite3BeginWriteOperation(pParse, 0, iDb); + z = sqlite3DbStrNDup(db, (char*)pAll->z, pAll->n); + testcase( z==0 ); + sqlite3NestedParse(pParse, + "INSERT INTO %Q." LEGACY_SCHEMA_TABLE + " VALUES('trigger',%Q,%Q,0,'CREATE TRIGGER %q')", + db->aDb[iDb].zDbSName, zName, + pTrig->table, z); + sqlite3DbFree(db, z); + sqlite3ChangeCookie(pParse, iDb); + sqlite3VdbeAddParseSchemaOp(v, iDb, + sqlite3MPrintf(db, "type='trigger' AND name='%q'", zName), 0); + } + + if( db->init.busy ){ + Trigger *pLink = pTrig; + Hash *pHash = &db->aDb[iDb].pSchema->trigHash; + assert( sqlite3SchemaMutexHeld(db, iDb, 0) ); + assert( pLink!=0 ); + pTrig = sqlite3HashInsert(pHash, zName, pTrig); + if( pTrig ){ + sqlite3OomFault(db); + }else if( pLink->pSchema==pLink->pTabSchema ){ + Table *pTab; + pTab = sqlite3HashFind(&pLink->pTabSchema->tblHash, pLink->table); + assert( pTab!=0 ); + pLink->pNext = pTab->pTrigger; + pTab->pTrigger = pLink; + } + } + +triggerfinish_cleanup: + sqlite3DeleteTrigger(db, pTrig); + assert( IN_RENAME_OBJECT || !pParse->pNewTrigger ); + sqlite3DeleteTriggerStep(db, pStepList); +} + +/* +** Duplicate a range of text from an SQL statement, then convert all +** whitespace characters into ordinary space characters. +*/ +static char *triggerSpanDup(sqlite3 *db, const char *zStart, const char *zEnd){ + char *z = sqlite3DbSpanDup(db, zStart, zEnd); + int i; + if( z ) for(i=0; z[i]; i++) if( sqlite3Isspace(z[i]) ) z[i] = ' '; + return z; +} + +/* +** 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 *sqlite3TriggerSelectStep( + sqlite3 *db, /* Database connection */ + Select *pSelect, /* The SELECT statement */ + const char *zStart, /* Start of SQL text */ + const char *zEnd /* End of SQL text */ +){ + TriggerStep *pTriggerStep = sqlite3DbMallocZero(db, sizeof(TriggerStep)); + if( pTriggerStep==0 ) { + sqlite3SelectDelete(db, pSelect); + return 0; + } + pTriggerStep->op = TK_SELECT; + pTriggerStep->pSelect = pSelect; + pTriggerStep->orconf = OE_Default; + pTriggerStep->zSpan = triggerSpanDup(db, zStart, zEnd); + return pTriggerStep; +} + +/* +** Allocate space to hold a new trigger step. The allocated space +** holds both the TriggerStep object and the TriggerStep.target.z string. +** +** If an OOM error occurs, NULL is returned and db->mallocFailed is set. +*/ +static TriggerStep *triggerStepAllocate( + Parse *pParse, /* Parser context */ + u8 op, /* Trigger opcode */ + Token *pName, /* The target name */ + const char *zStart, /* Start of SQL text */ + const char *zEnd /* End of SQL text */ +){ + sqlite3 *db = pParse->db; + TriggerStep *pTriggerStep; + + if( pParse->nErr ) return 0; + pTriggerStep = sqlite3DbMallocZero(db, sizeof(TriggerStep) + pName->n + 1); + if( pTriggerStep ){ + char *z = (char*)&pTriggerStep[1]; + memcpy(z, pName->z, pName->n); + sqlite3Dequote(z); + pTriggerStep->zTarget = z; + pTriggerStep->op = op; + pTriggerStep->zSpan = triggerSpanDup(db, zStart, zEnd); + if( IN_RENAME_OBJECT ){ + sqlite3RenameTokenMap(pParse, pTriggerStep->zTarget, pName); + } + } + 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 *sqlite3TriggerInsertStep( + Parse *pParse, /* Parser */ + Token *pTableName, /* Name of the table into which we insert */ + IdList *pColumn, /* List of columns in pTableName to insert into */ + Select *pSelect, /* A SELECT statement that supplies values */ + u8 orconf, /* The conflict algorithm (OE_Abort, OE_Replace, etc.) */ + Upsert *pUpsert, /* ON CONFLICT clauses for upsert */ + const char *zStart, /* Start of SQL text */ + const char *zEnd /* End of SQL text */ +){ + sqlite3 *db = pParse->db; + TriggerStep *pTriggerStep; + + assert(pSelect != 0 || db->mallocFailed); + + pTriggerStep = triggerStepAllocate(pParse, TK_INSERT, pTableName,zStart,zEnd); + if( pTriggerStep ){ + if( IN_RENAME_OBJECT ){ + pTriggerStep->pSelect = pSelect; + pSelect = 0; + }else{ + pTriggerStep->pSelect = sqlite3SelectDup(db, pSelect, EXPRDUP_REDUCE); + } + pTriggerStep->pIdList = pColumn; + pTriggerStep->pUpsert = pUpsert; + pTriggerStep->orconf = orconf; + if( pUpsert ){ + sqlite3HasExplicitNulls(pParse, pUpsert->pUpsertTarget); + } + }else{ + testcase( pColumn ); + sqlite3IdListDelete(db, pColumn); + testcase( pUpsert ); + sqlite3UpsertDelete(db, pUpsert); + } + sqlite3SelectDelete(db, pSelect); + + 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 *sqlite3TriggerUpdateStep( + Parse *pParse, /* Parser */ + Token *pTableName, /* Name of the table to be updated */ + SrcList *pFrom, /* FROM clause for an UPDATE-FROM, or NULL */ + ExprList *pEList, /* The SET clause: list of column and new values */ + Expr *pWhere, /* The WHERE clause */ + u8 orconf, /* The conflict algorithm. (OE_Abort, OE_Ignore, etc) */ + const char *zStart, /* Start of SQL text */ + const char *zEnd /* End of SQL text */ +){ + sqlite3 *db = pParse->db; + TriggerStep *pTriggerStep; + + pTriggerStep = triggerStepAllocate(pParse, TK_UPDATE, pTableName,zStart,zEnd); + if( pTriggerStep ){ + if( IN_RENAME_OBJECT ){ + pTriggerStep->pExprList = pEList; + pTriggerStep->pWhere = pWhere; + pTriggerStep->pFrom = pFrom; + pEList = 0; + pWhere = 0; + pFrom = 0; + }else{ + pTriggerStep->pExprList = sqlite3ExprListDup(db, pEList, EXPRDUP_REDUCE); + pTriggerStep->pWhere = sqlite3ExprDup(db, pWhere, EXPRDUP_REDUCE); + pTriggerStep->pFrom = sqlite3SrcListDup(db, pFrom, EXPRDUP_REDUCE); + } + pTriggerStep->orconf = orconf; + } + sqlite3ExprListDelete(db, pEList); + sqlite3ExprDelete(db, pWhere); + sqlite3SrcListDelete(db, pFrom); + 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 *sqlite3TriggerDeleteStep( + Parse *pParse, /* Parser */ + Token *pTableName, /* The table from which rows are deleted */ + Expr *pWhere, /* The WHERE clause */ + const char *zStart, /* Start of SQL text */ + const char *zEnd /* End of SQL text */ +){ + sqlite3 *db = pParse->db; + TriggerStep *pTriggerStep; + + pTriggerStep = triggerStepAllocate(pParse, TK_DELETE, pTableName,zStart,zEnd); + if( pTriggerStep ){ + if( IN_RENAME_OBJECT ){ + pTriggerStep->pWhere = pWhere; + pWhere = 0; + }else{ + pTriggerStep->pWhere = sqlite3ExprDup(db, pWhere, EXPRDUP_REDUCE); + } + pTriggerStep->orconf = OE_Default; + } + sqlite3ExprDelete(db, pWhere); + return pTriggerStep; +} + +/* +** Recursively delete a Trigger structure +*/ +void sqlite3DeleteTrigger(sqlite3 *db, Trigger *pTrigger){ + if( pTrigger==0 || pTrigger->bReturning ) return; + sqlite3DeleteTriggerStep(db, pTrigger->step_list); + sqlite3DbFree(db, pTrigger->zName); + sqlite3DbFree(db, pTrigger->table); + sqlite3ExprDelete(db, pTrigger->pWhen); + sqlite3IdListDelete(db, pTrigger->pColumns); + sqlite3DbFree(db, 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 sqlite3DropTriggerPtr() routine does the +** same job as this routine except it takes a pointer to the trigger +** instead of the trigger name. +**/ +void sqlite3DropTrigger(Parse *pParse, SrcList *pName, int noErr){ + Trigger *pTrigger = 0; + int i; + const char *zDb; + const char *zName; + sqlite3 *db = pParse->db; + + if( db->mallocFailed ) goto drop_trigger_cleanup; + if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){ + goto drop_trigger_cleanup; + } + + assert( pName->nSrc==1 ); + zDb = pName->a[0].zDatabase; + zName = pName->a[0].zName; + assert( zDb!=0 || sqlite3BtreeHoldsAllMutexes(db) ); + for(i=OMIT_TEMPDB; i<db->nDb; i++){ + int j = (i<2) ? i^1 : i; /* Search TEMP before MAIN */ + if( zDb && sqlite3DbIsNamed(db, j, zDb)==0 ) continue; + assert( sqlite3SchemaMutexHeld(db, j, 0) ); + pTrigger = sqlite3HashFind(&(db->aDb[j].pSchema->trigHash), zName); + if( pTrigger ) break; + } + if( !pTrigger ){ + if( !noErr ){ + sqlite3ErrorMsg(pParse, "no such trigger: %S", pName->a); + }else{ + sqlite3CodeVerifyNamedSchema(pParse, zDb); + } + pParse->checkSchema = 1; + goto drop_trigger_cleanup; + } + sqlite3DropTriggerPtr(pParse, pTrigger); + +drop_trigger_cleanup: + sqlite3SrcListDelete(db, pName); +} + +/* +** Return a pointer to the Table structure for the table that a trigger +** is set on. +*/ +static Table *tableOfTrigger(Trigger *pTrigger){ + return sqlite3HashFind(&pTrigger->pTabSchema->tblHash, pTrigger->table); +} + + +/* +** 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 && pTable->pSchema==pTrigger->pSchema) || iDb==1 ); +#ifndef SQLITE_OMIT_AUTHORIZATION + if( pTable ){ + int code = SQLITE_DROP_TRIGGER; + const char *zDb = db->aDb[iDb].zDbSName; + 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. + */ + if( (v = sqlite3GetVdbe(pParse))!=0 ){ + sqlite3NestedParse(pParse, + "DELETE FROM %Q." LEGACY_SCHEMA_TABLE " WHERE name=%Q AND type='trigger'", + db->aDb[iDb].zDbSName, pTrigger->zName + ); + sqlite3ChangeCookie(pParse, iDb); + sqlite3VdbeAddOp4(v, OP_DropTrigger, iDb, 0, 0, pTrigger->zName, 0); + } +} + +/* +** Remove a trigger from the hash tables of the sqlite* pointer. +*/ +void sqlite3UnlinkAndDeleteTrigger(sqlite3 *db, int iDb, const char *zName){ + Trigger *pTrigger; + Hash *pHash; + + assert( sqlite3SchemaMutexHeld(db, iDb, 0) ); + pHash = &(db->aDb[iDb].pSchema->trigHash); + pTrigger = sqlite3HashInsert(pHash, zName, 0); + if( ALWAYS(pTrigger) ){ + if( pTrigger->pSchema==pTrigger->pTabSchema ){ + Table *pTab = tableOfTrigger(pTrigger); + if( pTab ){ + Trigger **pp; + for(pp=&pTab->pTrigger; *pp; pp=&((*pp)->pNext)){ + if( *pp==pTrigger ){ + *pp = (*pp)->pNext; + break; + } + } + } + } + sqlite3DeleteTrigger(db, pTrigger); + db->mDbFlags |= DBFLAG_SchemaChange; + } +} + +/* +** 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==0 || NEVER(pEList==0) ) return 1; + for(e=0; e<pEList->nExpr; e++){ + if( sqlite3IdListIndex(pIdList, pEList->a[e].zEName)>=0 ) return 1; + } + return 0; +} + +/* +** Return true if any TEMP triggers exist +*/ +static int tempTriggersExist(sqlite3 *db){ + if( NEVER(db->aDb[1].pSchema==0) ) return 0; + if( sqliteHashFirst(&db->aDb[1].pSchema->trigHash)==0 ) return 0; + return 1; +} + +/* +** Return a list of all triggers on table pTab if there exists at least +** one trigger that must be fired when an operation of type 'op' is +** performed on the table, and, if that operation is an UPDATE, if at +** least one of the columns in pChanges is being modified. +*/ +static SQLITE_NOINLINE Trigger *triggersReallyExist( + Parse *pParse, /* Parse context */ + Table *pTab, /* The table the contains the triggers */ + int op, /* one of TK_DELETE, TK_INSERT, TK_UPDATE */ + ExprList *pChanges, /* Columns that change in an UPDATE statement */ + int *pMask /* OUT: Mask of TRIGGER_BEFORE|TRIGGER_AFTER */ +){ + int mask = 0; + Trigger *pList = 0; + Trigger *p; + + pList = sqlite3TriggerList(pParse, pTab); + assert( pList==0 || IsVirtual(pTab)==0 + || (pList->bReturning && pList->pNext==0) ); + if( pList!=0 ){ + p = pList; + if( (pParse->db->flags & SQLITE_EnableTrigger)==0 + && pTab->pTrigger!=0 + ){ + /* The SQLITE_DBCONFIG_ENABLE_TRIGGER setting is off. That means that + ** only TEMP triggers are allowed. Truncate the pList so that it + ** includes only TEMP triggers */ + if( pList==pTab->pTrigger ){ + pList = 0; + goto exit_triggers_exist; + } + while( ALWAYS(p->pNext) && p->pNext!=pTab->pTrigger ) p = p->pNext; + p->pNext = 0; + p = pList; + } + do{ + if( p->op==op && checkColumnOverlap(p->pColumns, pChanges) ){ + mask |= p->tr_tm; + }else if( p->op==TK_RETURNING ){ + /* The first time a RETURNING trigger is seen, the "op" value tells + ** us what time of trigger it should be. */ + assert( sqlite3IsToplevel(pParse) ); + p->op = op; + if( IsVirtual(pTab) ){ + if( op!=TK_INSERT ){ + sqlite3ErrorMsg(pParse, + "%s RETURNING is not available on virtual tables", + op==TK_DELETE ? "DELETE" : "UPDATE"); + } + p->tr_tm = TRIGGER_BEFORE; + }else{ + p->tr_tm = TRIGGER_AFTER; + } + mask |= p->tr_tm; + }else if( p->bReturning && p->op==TK_INSERT && op==TK_UPDATE + && sqlite3IsToplevel(pParse) ){ + /* Also fire a RETURNING trigger for an UPSERT */ + mask |= p->tr_tm; + } + p = p->pNext; + }while( p ); + } +exit_triggers_exist: + if( pMask ){ + *pMask = mask; + } + return (mask ? pList : 0); +} +Trigger *sqlite3TriggersExist( + Parse *pParse, /* Parse context */ + Table *pTab, /* The table the contains the triggers */ + int op, /* one of TK_DELETE, TK_INSERT, TK_UPDATE */ + ExprList *pChanges, /* Columns that change in an UPDATE statement */ + int *pMask /* OUT: Mask of TRIGGER_BEFORE|TRIGGER_AFTER */ +){ + assert( pTab!=0 ); + if( (pTab->pTrigger==0 && !tempTriggersExist(pParse->db)) + || pParse->disableTriggers + ){ + if( pMask ) *pMask = 0; + return 0; + } + return triggersReallyExist(pParse,pTab,op,pChanges,pMask); +} + +/* +** Convert the pStep->zTarget string 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. +*/ +SrcList *sqlite3TriggerStepSrc( + Parse *pParse, /* The parsing context */ + TriggerStep *pStep /* The trigger containing the target token */ +){ + sqlite3 *db = pParse->db; + SrcList *pSrc; /* SrcList to be returned */ + char *zName = sqlite3DbStrDup(db, pStep->zTarget); + pSrc = sqlite3SrcListAppend(pParse, 0, 0, 0); + assert( pSrc==0 || pSrc->nSrc==1 ); + assert( zName || pSrc==0 ); + if( pSrc ){ + Schema *pSchema = pStep->pTrig->pSchema; + pSrc->a[0].zName = zName; + if( pSchema!=db->aDb[1].pSchema ){ + pSrc->a[0].pSchema = pSchema; + } + if( pStep->pFrom ){ + SrcList *pDup = sqlite3SrcListDup(db, pStep->pFrom, 0); + if( pDup && pDup->nSrc>1 && !IN_RENAME_OBJECT ){ + Select *pSubquery; + Token as; + pSubquery = sqlite3SelectNew(pParse,0,pDup,0,0,0,0,SF_NestedFrom,0); + as.n = 0; + as.z = 0; + pDup = sqlite3SrcListAppendFromTerm(pParse,0,0,0,&as,pSubquery,0); + } + pSrc = sqlite3SrcListAppendList(pParse, pSrc, pDup); + } + }else{ + sqlite3DbFree(db, zName); + } + return pSrc; +} + +/* +** Return true if the pExpr term from the RETURNING clause argument +** list is of the form "*". Raise an error if the terms if of the +** form "table.*". +*/ +static int isAsteriskTerm( + Parse *pParse, /* Parsing context */ + Expr *pTerm /* A term in the RETURNING clause */ +){ + assert( pTerm!=0 ); + if( pTerm->op==TK_ASTERISK ) return 1; + if( pTerm->op!=TK_DOT ) return 0; + assert( pTerm->pRight!=0 ); + assert( pTerm->pLeft!=0 ); + if( pTerm->pRight->op!=TK_ASTERISK ) return 0; + sqlite3ErrorMsg(pParse, "RETURNING may not use \"TABLE.*\" wildcards"); + return 1; +} + +/* The input list pList is the list of result set terms from a RETURNING +** clause. The table that we are returning from is pTab. +** +** This routine makes a copy of the pList, and at the same time expands +** any "*" wildcards to be the complete set of columns from pTab. +*/ +static ExprList *sqlite3ExpandReturning( + Parse *pParse, /* Parsing context */ + ExprList *pList, /* The arguments to RETURNING */ + Table *pTab /* The table being updated */ +){ + ExprList *pNew = 0; + sqlite3 *db = pParse->db; + int i; + + for(i=0; i<pList->nExpr; i++){ + Expr *pOldExpr = pList->a[i].pExpr; + if( NEVER(pOldExpr==0) ) continue; + if( isAsteriskTerm(pParse, pOldExpr) ){ + int jj; + for(jj=0; jj<pTab->nCol; jj++){ + Expr *pNewExpr; + if( IsHiddenColumn(pTab->aCol+jj) ) continue; + pNewExpr = sqlite3Expr(db, TK_ID, pTab->aCol[jj].zCnName); + pNew = sqlite3ExprListAppend(pParse, pNew, pNewExpr); + if( !db->mallocFailed ){ + struct ExprList_item *pItem = &pNew->a[pNew->nExpr-1]; + pItem->zEName = sqlite3DbStrDup(db, pTab->aCol[jj].zCnName); + pItem->fg.eEName = ENAME_NAME; + } + } + }else{ + Expr *pNewExpr = sqlite3ExprDup(db, pOldExpr, 0); + pNew = sqlite3ExprListAppend(pParse, pNew, pNewExpr); + if( !db->mallocFailed && ALWAYS(pList->a[i].zEName!=0) ){ + struct ExprList_item *pItem = &pNew->a[pNew->nExpr-1]; + pItem->zEName = sqlite3DbStrDup(db, pList->a[i].zEName); + pItem->fg.eEName = pList->a[i].fg.eEName; + } + } + } + return pNew; +} + +/* +** Generate code for the RETURNING trigger. Unlike other triggers +** that invoke a subprogram in the bytecode, the code for RETURNING +** is generated in-line. +*/ +static void codeReturningTrigger( + Parse *pParse, /* Parse context */ + Trigger *pTrigger, /* The trigger step that defines the RETURNING */ + Table *pTab, /* The table to code triggers from */ + int regIn /* The first in an array of registers */ +){ + Vdbe *v = pParse->pVdbe; + sqlite3 *db = pParse->db; + ExprList *pNew; + Returning *pReturning; + Select sSelect; + SrcList sFrom; + + assert( v!=0 ); + if( !pParse->bReturning ){ + /* This RETURNING trigger must be for a different statement as + ** this statement lacks a RETURNING clause. */ + return; + } + assert( db->pParse==pParse ); + pReturning = pParse->u1.pReturning; + if( pTrigger != &(pReturning->retTrig) ){ + /* This RETURNING trigger is for a different statement */ + return; + } + memset(&sSelect, 0, sizeof(sSelect)); + memset(&sFrom, 0, sizeof(sFrom)); + sSelect.pEList = sqlite3ExprListDup(db, pReturning->pReturnEL, 0); + sSelect.pSrc = &sFrom; + sFrom.nSrc = 1; + sFrom.a[0].pTab = pTab; + sFrom.a[0].iCursor = -1; + sqlite3SelectPrep(pParse, &sSelect, 0); + if( pParse->nErr==0 ){ + assert( db->mallocFailed==0 ); + sqlite3GenerateColumnNames(pParse, &sSelect); + } + sqlite3ExprListDelete(db, sSelect.pEList); + pNew = sqlite3ExpandReturning(pParse, pReturning->pReturnEL, pTab); + if( pParse->nErr==0 ){ + NameContext sNC; + memset(&sNC, 0, sizeof(sNC)); + if( pReturning->nRetCol==0 ){ + pReturning->nRetCol = pNew->nExpr; + pReturning->iRetCur = pParse->nTab++; + } + sNC.pParse = pParse; + sNC.uNC.iBaseReg = regIn; + sNC.ncFlags = NC_UBaseReg; + pParse->eTriggerOp = pTrigger->op; + pParse->pTriggerTab = pTab; + if( sqlite3ResolveExprListNames(&sNC, pNew)==SQLITE_OK + && ALWAYS(!db->mallocFailed) + ){ + int i; + int nCol = pNew->nExpr; + int reg = pParse->nMem+1; + pParse->nMem += nCol+2; + pReturning->iRetReg = reg; + for(i=0; i<nCol; i++){ + Expr *pCol = pNew->a[i].pExpr; + assert( pCol!=0 ); /* Due to !db->mallocFailed ~9 lines above */ + sqlite3ExprCodeFactorable(pParse, pCol, reg+i); + if( sqlite3ExprAffinity(pCol)==SQLITE_AFF_REAL ){ + sqlite3VdbeAddOp1(v, OP_RealAffinity, reg+i); + } + } + sqlite3VdbeAddOp3(v, OP_MakeRecord, reg, i, reg+i); + sqlite3VdbeAddOp2(v, OP_NewRowid, pReturning->iRetCur, reg+i+1); + sqlite3VdbeAddOp3(v, OP_Insert, pReturning->iRetCur, reg+i, reg+i+1); + } + } + sqlite3ExprListDelete(db, pNew); + pParse->eTriggerOp = 0; + pParse->pTriggerTab = 0; +} + + + +/* +** Generate VDBE code for the statements inside the body of a single +** trigger. +*/ +static int codeTriggerProgram( + Parse *pParse, /* The parser context */ + TriggerStep *pStepList, /* List of statements inside the trigger body */ + int orconf /* Conflict algorithm. (OE_Abort, etc) */ +){ + TriggerStep *pStep; + Vdbe *v = pParse->pVdbe; + sqlite3 *db = pParse->db; + + assert( pParse->pTriggerTab && pParse->pToplevel ); + assert( pStepList ); + assert( v!=0 ); + for(pStep=pStepList; pStep; pStep=pStep->pNext){ + /* Figure out the ON CONFLICT policy that will be used for this step + ** of the trigger program. If the statement that caused this trigger + ** to fire had an explicit ON CONFLICT, then use it. Otherwise, use + ** the ON CONFLICT policy that was specified as part of the trigger + ** step statement. Example: + ** + ** CREATE TRIGGER AFTER INSERT ON t1 BEGIN; + ** INSERT OR REPLACE INTO t2 VALUES(new.a, new.b); + ** END; + ** + ** INSERT INTO t1 ... ; -- insert into t2 uses REPLACE policy + ** INSERT OR IGNORE INTO t1 ... ; -- insert into t2 uses IGNORE policy + */ + pParse->eOrconf = (orconf==OE_Default)?pStep->orconf:(u8)orconf; + assert( pParse->okConstFactor==0 ); + +#ifndef SQLITE_OMIT_TRACE + if( pStep->zSpan ){ + sqlite3VdbeAddOp4(v, OP_Trace, 0x7fffffff, 1, 0, + sqlite3MPrintf(db, "-- %s", pStep->zSpan), + P4_DYNAMIC); + } +#endif + + switch( pStep->op ){ + case TK_UPDATE: { + sqlite3Update(pParse, + sqlite3TriggerStepSrc(pParse, pStep), + sqlite3ExprListDup(db, pStep->pExprList, 0), + sqlite3ExprDup(db, pStep->pWhere, 0), + pParse->eOrconf, 0, 0, 0 + ); + sqlite3VdbeAddOp0(v, OP_ResetCount); + break; + } + case TK_INSERT: { + sqlite3Insert(pParse, + sqlite3TriggerStepSrc(pParse, pStep), + sqlite3SelectDup(db, pStep->pSelect, 0), + sqlite3IdListDup(db, pStep->pIdList), + pParse->eOrconf, + sqlite3UpsertDup(db, pStep->pUpsert) + ); + sqlite3VdbeAddOp0(v, OP_ResetCount); + break; + } + case TK_DELETE: { + sqlite3DeleteFrom(pParse, + sqlite3TriggerStepSrc(pParse, pStep), + sqlite3ExprDup(db, pStep->pWhere, 0), 0, 0 + ); + sqlite3VdbeAddOp0(v, OP_ResetCount); + break; + } + default: assert( pStep->op==TK_SELECT ); { + SelectDest sDest; + Select *pSelect = sqlite3SelectDup(db, pStep->pSelect, 0); + sqlite3SelectDestInit(&sDest, SRT_Discard, 0); + sqlite3Select(pParse, pSelect, &sDest); + sqlite3SelectDelete(db, pSelect); + break; + } + } + } + + return 0; +} + +#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS +/* +** This function is used to add VdbeComment() annotations to a VDBE +** program. It is not used in production code, only for debugging. +*/ +static const char *onErrorText(int onError){ + switch( onError ){ + case OE_Abort: return "abort"; + case OE_Rollback: return "rollback"; + case OE_Fail: return "fail"; + case OE_Replace: return "replace"; + case OE_Ignore: return "ignore"; + case OE_Default: return "default"; + } + return "n/a"; +} +#endif + +/* +** Parse context structure pFrom has just been used to create a sub-vdbe +** (trigger program). If an error has occurred, transfer error information +** from pFrom to pTo. +*/ +static void transferParseError(Parse *pTo, Parse *pFrom){ + assert( pFrom->zErrMsg==0 || pFrom->nErr ); + assert( pTo->zErrMsg==0 || pTo->nErr ); + if( pTo->nErr==0 ){ + pTo->zErrMsg = pFrom->zErrMsg; + pTo->nErr = pFrom->nErr; + pTo->rc = pFrom->rc; + }else{ + sqlite3DbFree(pFrom->db, pFrom->zErrMsg); + } +} + +/* +** Create and populate a new TriggerPrg object with a sub-program +** implementing trigger pTrigger with ON CONFLICT policy orconf. +*/ +static TriggerPrg *codeRowTrigger( + Parse *pParse, /* Current parse context */ + Trigger *pTrigger, /* Trigger to code */ + Table *pTab, /* The table pTrigger is attached to */ + int orconf /* ON CONFLICT policy to code trigger program with */ +){ + Parse *pTop = sqlite3ParseToplevel(pParse); + sqlite3 *db = pParse->db; /* Database handle */ + TriggerPrg *pPrg; /* Value to return */ + Expr *pWhen = 0; /* Duplicate of trigger WHEN expression */ + Vdbe *v; /* Temporary VM */ + NameContext sNC; /* Name context for sub-vdbe */ + SubProgram *pProgram = 0; /* Sub-vdbe for trigger program */ + int iEndTrigger = 0; /* Label to jump to if WHEN is false */ + Parse sSubParse; /* Parse context for sub-vdbe */ + + assert( pTrigger->zName==0 || pTab==tableOfTrigger(pTrigger) ); + assert( pTop->pVdbe ); + + /* Allocate the TriggerPrg and SubProgram objects. To ensure that they + ** are freed if an error occurs, link them into the Parse.pTriggerPrg + ** list of the top-level Parse object sooner rather than later. */ + pPrg = sqlite3DbMallocZero(db, sizeof(TriggerPrg)); + if( !pPrg ) return 0; + pPrg->pNext = pTop->pTriggerPrg; + pTop->pTriggerPrg = pPrg; + pPrg->pProgram = pProgram = sqlite3DbMallocZero(db, sizeof(SubProgram)); + if( !pProgram ) return 0; + sqlite3VdbeLinkSubProgram(pTop->pVdbe, pProgram); + pPrg->pTrigger = pTrigger; + pPrg->orconf = orconf; + pPrg->aColmask[0] = 0xffffffff; + pPrg->aColmask[1] = 0xffffffff; + + /* Allocate and populate a new Parse context to use for coding the + ** trigger sub-program. */ + sqlite3ParseObjectInit(&sSubParse, db); + memset(&sNC, 0, sizeof(sNC)); + sNC.pParse = &sSubParse; + sSubParse.pTriggerTab = pTab; + sSubParse.pToplevel = pTop; + sSubParse.zAuthContext = pTrigger->zName; + sSubParse.eTriggerOp = pTrigger->op; + sSubParse.nQueryLoop = pParse->nQueryLoop; + sSubParse.prepFlags = pParse->prepFlags; + + v = sqlite3GetVdbe(&sSubParse); + if( v ){ + VdbeComment((v, "Start: %s.%s (%s %s%s%s ON %s)", + pTrigger->zName, onErrorText(orconf), + (pTrigger->tr_tm==TRIGGER_BEFORE ? "BEFORE" : "AFTER"), + (pTrigger->op==TK_UPDATE ? "UPDATE" : ""), + (pTrigger->op==TK_INSERT ? "INSERT" : ""), + (pTrigger->op==TK_DELETE ? "DELETE" : ""), + pTab->zName + )); +#ifndef SQLITE_OMIT_TRACE + if( pTrigger->zName ){ + sqlite3VdbeChangeP4(v, -1, + sqlite3MPrintf(db, "-- TRIGGER %s", pTrigger->zName), P4_DYNAMIC + ); + } +#endif + + /* If one was specified, code the WHEN clause. If it evaluates to false + ** (or NULL) the sub-vdbe is immediately halted by jumping to the + ** OP_Halt inserted at the end of the program. */ + if( pTrigger->pWhen ){ + pWhen = sqlite3ExprDup(db, pTrigger->pWhen, 0); + if( db->mallocFailed==0 + && SQLITE_OK==sqlite3ResolveExprNames(&sNC, pWhen) + ){ + iEndTrigger = sqlite3VdbeMakeLabel(&sSubParse); + sqlite3ExprIfFalse(&sSubParse, pWhen, iEndTrigger, SQLITE_JUMPIFNULL); + } + sqlite3ExprDelete(db, pWhen); + } + + /* Code the trigger program into the sub-vdbe. */ + codeTriggerProgram(&sSubParse, pTrigger->step_list, orconf); + + /* Insert an OP_Halt at the end of the sub-program. */ + if( iEndTrigger ){ + sqlite3VdbeResolveLabel(v, iEndTrigger); + } + sqlite3VdbeAddOp0(v, OP_Halt); + VdbeComment((v, "End: %s.%s", pTrigger->zName, onErrorText(orconf))); + transferParseError(pParse, &sSubParse); + + if( pParse->nErr==0 ){ + assert( db->mallocFailed==0 ); + pProgram->aOp = sqlite3VdbeTakeOpArray(v, &pProgram->nOp, &pTop->nMaxArg); + } + pProgram->nMem = sSubParse.nMem; + pProgram->nCsr = sSubParse.nTab; + pProgram->token = (void *)pTrigger; + pPrg->aColmask[0] = sSubParse.oldmask; + pPrg->aColmask[1] = sSubParse.newmask; + sqlite3VdbeDelete(v); + }else{ + transferParseError(pParse, &sSubParse); + } + + assert( !sSubParse.pTriggerPrg && !sSubParse.nMaxArg ); + sqlite3ParseObjectReset(&sSubParse); + return pPrg; +} + +/* +** Return a pointer to a TriggerPrg object containing the sub-program for +** trigger pTrigger with default ON CONFLICT algorithm orconf. If no such +** TriggerPrg object exists, a new object is allocated and populated before +** being returned. +*/ +static TriggerPrg *getRowTrigger( + Parse *pParse, /* Current parse context */ + Trigger *pTrigger, /* Trigger to code */ + Table *pTab, /* The table trigger pTrigger is attached to */ + int orconf /* ON CONFLICT algorithm. */ +){ + Parse *pRoot = sqlite3ParseToplevel(pParse); + TriggerPrg *pPrg; + + assert( pTrigger->zName==0 || pTab==tableOfTrigger(pTrigger) ); + + /* It may be that this trigger has already been coded (or is in the + ** process of being coded). If this is the case, then an entry with + ** a matching TriggerPrg.pTrigger field will be present somewhere + ** in the Parse.pTriggerPrg list. Search for such an entry. */ + for(pPrg=pRoot->pTriggerPrg; + pPrg && (pPrg->pTrigger!=pTrigger || pPrg->orconf!=orconf); + pPrg=pPrg->pNext + ); + + /* If an existing TriggerPrg could not be located, create a new one. */ + if( !pPrg ){ + pPrg = codeRowTrigger(pParse, pTrigger, pTab, orconf); + pParse->db->errByteOffset = -1; + } + + return pPrg; +} + +/* +** Generate code for the trigger program associated with trigger p on +** table pTab. The reg, orconf and ignoreJump parameters passed to this +** function are the same as those described in the header function for +** sqlite3CodeRowTrigger() +*/ +void sqlite3CodeRowTriggerDirect( + Parse *pParse, /* Parse context */ + Trigger *p, /* Trigger to code */ + Table *pTab, /* The table to code triggers from */ + int reg, /* Reg array containing OLD.* and NEW.* values */ + int orconf, /* ON CONFLICT policy */ + int ignoreJump /* Instruction to jump to for RAISE(IGNORE) */ +){ + Vdbe *v = sqlite3GetVdbe(pParse); /* Main VM */ + TriggerPrg *pPrg; + pPrg = getRowTrigger(pParse, p, pTab, orconf); + assert( pPrg || pParse->nErr ); + + /* Code the OP_Program opcode in the parent VDBE. P4 of the OP_Program + ** is a pointer to the sub-vdbe containing the trigger program. */ + if( pPrg ){ + int bRecursive = (p->zName && 0==(pParse->db->flags&SQLITE_RecTriggers)); + + sqlite3VdbeAddOp4(v, OP_Program, reg, ignoreJump, ++pParse->nMem, + (const char *)pPrg->pProgram, P4_SUBPROGRAM); + VdbeComment( + (v, "Call: %s.%s", (p->zName?p->zName:"fkey"), onErrorText(orconf))); + + /* Set the P5 operand of the OP_Program instruction to non-zero if + ** recursive invocation of this trigger program is disallowed. Recursive + ** invocation is disallowed if (a) the sub-program is really a trigger, + ** not a foreign key action, and (b) the flag to enable recursive triggers + ** is clear. */ + sqlite3VdbeChangeP5(v, (u8)bRecursive); + } +} + +/* +** This is called to code the required FOR EACH ROW triggers for an operation +** on table pTab. The operation to code triggers for (INSERT, UPDATE or DELETE) +** is given by the op parameter. The tr_tm parameter determines whether the +** BEFORE or AFTER triggers are coded. If the operation is an UPDATE, then +** parameter pChanges is passed the list of columns being modified. +** +** If there are no triggers that fire at the specified time for the specified +** operation on pTab, this function is a no-op. +** +** The reg argument is the address of the first in an array of registers +** that contain the values substituted for the new.* and old.* references +** in the trigger program. If N is the number of columns in table pTab +** (a copy of pTab->nCol), then registers are populated as follows: +** +** Register Contains +** ------------------------------------------------------ +** reg+0 OLD.rowid +** reg+1 OLD.* value of left-most column of pTab +** ... ... +** reg+N OLD.* value of right-most column of pTab +** reg+N+1 NEW.rowid +** reg+N+2 NEW.* value of left-most column of pTab +** ... ... +** reg+N+N+1 NEW.* value of right-most column of pTab +** +** For ON DELETE triggers, the registers containing the NEW.* values will +** never be accessed by the trigger program, so they are not allocated or +** populated by the caller (there is no data to populate them with anyway). +** Similarly, for ON INSERT triggers the values stored in the OLD.* registers +** are never accessed, and so are not allocated by the caller. So, for an +** ON INSERT trigger, the value passed to this function as parameter reg +** is not a readable register, although registers (reg+N) through +** (reg+N+N+1) are. +** +** Parameter orconf is the default conflict resolution algorithm for the +** trigger program to use (REPLACE, IGNORE etc.). Parameter ignoreJump +** is the instruction that control should jump to if a trigger program +** raises an IGNORE exception. +*/ +void sqlite3CodeRowTrigger( + Parse *pParse, /* Parse context */ + Trigger *pTrigger, /* List of triggers on table pTab */ + int op, /* One of TK_UPDATE, TK_INSERT, TK_DELETE */ + ExprList *pChanges, /* Changes list for any UPDATE OF triggers */ + int tr_tm, /* One of TRIGGER_BEFORE, TRIGGER_AFTER */ + Table *pTab, /* The table to code triggers from */ + int reg, /* The first in an array of registers (see above) */ + int orconf, /* ON CONFLICT policy */ + int ignoreJump /* Instruction to jump to for RAISE(IGNORE) */ +){ + Trigger *p; /* Used to iterate through pTrigger list */ + + assert( op==TK_UPDATE || op==TK_INSERT || op==TK_DELETE ); + assert( tr_tm==TRIGGER_BEFORE || tr_tm==TRIGGER_AFTER ); + assert( (op==TK_UPDATE)==(pChanges!=0) ); + + for(p=pTrigger; p; p=p->pNext){ + + /* Sanity checking: The schema for the trigger and for the table are + ** always defined. The trigger must be in the same schema as the table + ** or else it must be a TEMP trigger. */ + assert( p->pSchema!=0 ); + assert( p->pTabSchema!=0 ); + assert( p->pSchema==p->pTabSchema + || p->pSchema==pParse->db->aDb[1].pSchema ); + + /* Determine whether we should code this trigger. One of two choices: + ** 1. The trigger is an exact match to the current DML statement + ** 2. This is a RETURNING trigger for INSERT but we are currently + ** doing the UPDATE part of an UPSERT. + */ + if( (p->op==op || (p->bReturning && p->op==TK_INSERT && op==TK_UPDATE)) + && p->tr_tm==tr_tm + && checkColumnOverlap(p->pColumns, pChanges) + ){ + if( !p->bReturning ){ + sqlite3CodeRowTriggerDirect(pParse, p, pTab, reg, orconf, ignoreJump); + }else if( sqlite3IsToplevel(pParse) ){ + codeReturningTrigger(pParse, p, pTab, reg); + } + } + } +} + +/* +** Triggers may access values stored in the old.* or new.* pseudo-table. +** This function returns a 32-bit bitmask indicating which columns of the +** old.* or new.* tables actually are used by triggers. This information +** may be used by the caller, for example, to avoid having to load the entire +** old.* record into memory when executing an UPDATE or DELETE command. +** +** Bit 0 of the returned mask is set if the left-most column of the +** table may be accessed using an [old|new].<col> reference. Bit 1 is set if +** the second leftmost column value is required, and so on. If there +** are more than 32 columns in the table, and at least one of the columns +** with an index greater than 32 may be accessed, 0xffffffff is returned. +** +** It is not possible to determine if the old.rowid or new.rowid column is +** accessed by triggers. The caller must always assume that it is. +** +** Parameter isNew must be either 1 or 0. If it is 0, then the mask returned +** applies to the old.* table. If 1, the new.* table. +** +** Parameter tr_tm must be a mask with one or both of the TRIGGER_BEFORE +** and TRIGGER_AFTER bits set. Values accessed by BEFORE triggers are only +** included in the returned mask if the TRIGGER_BEFORE bit is set in the +** tr_tm parameter. Similarly, values accessed by AFTER triggers are only +** included in the returned mask if the TRIGGER_AFTER bit is set in tr_tm. +*/ +u32 sqlite3TriggerColmask( + Parse *pParse, /* Parse context */ + Trigger *pTrigger, /* List of triggers on table pTab */ + ExprList *pChanges, /* Changes list for any UPDATE OF triggers */ + int isNew, /* 1 for new.* ref mask, 0 for old.* ref mask */ + int tr_tm, /* Mask of TRIGGER_BEFORE|TRIGGER_AFTER */ + Table *pTab, /* The table to code triggers from */ + int orconf /* Default ON CONFLICT policy for trigger steps */ +){ + const int op = pChanges ? TK_UPDATE : TK_DELETE; + u32 mask = 0; + Trigger *p; + + assert( isNew==1 || isNew==0 ); + if( IsView(pTab) ){ + return 0xffffffff; + } + for(p=pTrigger; p; p=p->pNext){ + if( p->op==op + && (tr_tm&p->tr_tm) + && checkColumnOverlap(p->pColumns,pChanges) + ){ + if( p->bReturning ){ + mask = 0xffffffff; + }else{ + TriggerPrg *pPrg; + pPrg = getRowTrigger(pParse, p, pTab, orconf); + if( pPrg ){ + mask |= pPrg->aColmask[isNew]; + } + } + } + } + + return mask; +} + +#endif /* !defined(SQLITE_OMIT_TRIGGER) */ |