--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/engine/sqlite/src/trigger.cpp Thu Feb 25 14:29:19 2010 +0000
@@ -0,0 +1,840 @@
+/*
+**
+** 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"
+
+#ifndef SQLITE_OMIT_TRIGGER
+/*
+** Delete a linked list of TriggerStep structures.
+*/
+void sqlite3DeleteTriggerStep(TriggerStep *pTriggerStep){
+ while( pTriggerStep ){
+ TriggerStep * pTmp = pTriggerStep;
+ pTriggerStep = pTriggerStep->pNext;
+
+ if( pTmp->target.dyn ) sqlite3_free((char*)pTmp->target.z);
+ sqlite3ExprDelete(pTmp->pWhere);
+ sqlite3ExprListDelete(pTmp->pExprList);
+ sqlite3SelectDelete(pTmp->pSelect);
+ sqlite3IdListDelete(pTmp->pIdList);
+
+ sqlite3_free(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
+** 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;
+ Table *pTab;
+ char *zName = 0; /* Name of the trigger */
+ sqlite3 *db = pParse->db;
+ int iDb; /* The database to store the trigger in */
+ Token *pName; /* The unqualified db name */
+ DbFixer sFix;
+ int iTabDb;
+
+ assert( pName1!=0 ); /* pName1->z might be NULL, but not pName1 itself */
+ assert( pName2!=0 );
+ 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 the trigger will be created in */
+ iDb = sqlite3TwoPartName(pParse, pName1, pName2, &pName);
+ if( iDb<0 ){
+ goto trigger_cleanup;
+ }
+ }
+
+ /* 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.
+ */
+ if( !pTableName || db->mallocFailed ){
+ goto trigger_cleanup;
+ }
+ pTab = sqlite3SrcListLookup(pParse, pTableName);
+ if( 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 );
+ if( sqlite3FixInit(&sFix, pParse, iDb, "trigger", pName) &&
+ sqlite3FixSrcList(&sFix, pTableName) ){
+ goto trigger_cleanup;
+ }
+ pTab = sqlite3SrcListLookup(pParse, pTableName);
+ if( !pTab ){
+ /* The table does not exist. */
+ goto trigger_cleanup;
+ }
+ if( IsVirtual(pTab) ){
+ sqlite3ErrorMsg(pParse, "cannot create triggers on virtual tables");
+ goto trigger_cleanup;
+ }
+
+ /* Check that the trigger name is not reserved and that no trigger of the
+ ** specified name exists */
+ zName = sqlite3NameFromToken(db, pName);
+ if( !zName || SQLITE_OK!=sqlite3CheckObjectName(pParse, zName) ){
+ goto trigger_cleanup;
+ }
+ if( sqlite3HashFind(&(db->aDb[iDb].pSchema->trigHash), zName,strlen(zName)) ){
+ if( !noErr ){
+ sqlite3ErrorMsg(pParse, "trigger %T already exists", pName);
+ }
+ 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");
+ pParse->nErr++;
+ goto trigger_cleanup;
+ }
+
+ /* INSTEAD of triggers are only for views and views only support INSTEAD
+ ** of triggers.
+ */
+ if( pTab->pSelect && tr_tm!=TK_INSTEAD ){
+ sqlite3ErrorMsg(pParse, "cannot create %s trigger on view: %S",
+ (tr_tm == TK_BEFORE)?"BEFORE":"AFTER", pTableName, 0);
+ goto trigger_cleanup;
+ }
+ if( !pTab->pSelect && tr_tm==TK_INSTEAD ){
+ sqlite3ErrorMsg(pParse, "cannot create INSTEAD OF"
+ " trigger on table: %S", pTableName, 0);
+ goto trigger_cleanup;
+ }
+ iTabDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+
+#ifndef SQLITE_OMIT_AUTHORIZATION
+ {
+ int code = SQLITE_CREATE_TRIGGER;
+ const char *zDb = db->aDb[iTabDb].zName;
+ const char *zDbTrig = isTemp ? db->aDb[1].zName : 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->name = zName;
+ zName = 0;
+ pTrigger->table = sqlite3DbStrDup(db, pTableName->a[0].zName);
+ pTrigger->pSchema = db->aDb[iDb].pSchema;
+ pTrigger->pTabSchema = pTab->pSchema;
+ pTrigger->op = op;
+ pTrigger->tr_tm = tr_tm==TK_BEFORE ? TRIGGER_BEFORE : TRIGGER_AFTER;
+ pTrigger->pWhen = sqlite3ExprDup(db, pWhen);
+ pTrigger->pColumns = sqlite3IdListDup(db, pColumns);
+ sqlite3TokenCopy(db, &pTrigger->nameToken,pName);
+ assert( pParse->pNewTrigger==0 );
+ pParse->pNewTrigger = pTrigger;
+
+trigger_cleanup:
+ sqlite3_free(zName);
+ sqlite3SrcListDelete(pTableName);
+ sqlite3IdListDelete(pColumns);
+ sqlite3ExprDelete(pWhen);
+ if( !pParse->pNewTrigger ){
+ sqlite3DeleteTrigger(pTrigger);
+ }else{
+ assert( pParse->pNewTrigger==pTrigger );
+ }
+}
+
+/*
+** 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 = 0; /* The trigger whose construction is finishing up */
+ sqlite3 *db = pParse->db; /* The database */
+ DbFixer sFix;
+ int iDb; /* Database containing the trigger */
+
+ pTrig = pParse->pNewTrigger;
+ pParse->pNewTrigger = 0;
+ if( pParse->nErr || !pTrig ) goto triggerfinish_cleanup;
+ iDb = sqlite3SchemaToIndex(pParse->db, pTrig->pSchema);
+ pTrig->step_list = pStepList;
+ while( pStepList ){
+ pStepList->pTrig = pTrig;
+ pStepList = pStepList->pNext;
+ }
+ if( sqlite3FixInit(&sFix, pParse, iDb, "trigger", &pTrig->nameToken)
+ && sqlite3FixTriggerStep(&sFix, pTrig->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 const VdbeOpList insertTrig[] = {
+ { OP_NewRowid, 0, 0, 0 },
+ { OP_String8, 0, 0, "trigger" },
+ { OP_String8, 0, 0, 0 }, /* 2: trigger name */
+ { OP_String8, 0, 0, 0 }, /* 3: table name */
+ { OP_Integer, 0, 0, 0 },
+ { OP_String8, 0, 0, "CREATE TRIGGER "},
+ { OP_String8, 0, 0, 0 }, /* 6: SQL */
+ { OP_Concat, 0, 0, 0 },
+ { OP_MakeRecord, 5, 0, "aaada" },
+ { OP_Insert, 0, 0, 0 },
+ };
+ int addr;
+ Vdbe *v;
+
+ /* Make an entry in the sqlite_master table */
+ v = sqlite3GetVdbe(pParse);
+ if( v==0 ) goto triggerfinish_cleanup;
+ sqlite3BeginWriteOperation(pParse, 0, iDb);
+ sqlite3OpenMasterTable(pParse, iDb);
+ addr = sqlite3VdbeAddOpList(v, ArraySize(insertTrig), insertTrig);
+ sqlite3VdbeChangeP3(v, addr+2, pTrig->name, 0);
+ sqlite3VdbeChangeP3(v, addr+3, pTrig->table, 0);
+ sqlite3VdbeChangeP3(v, addr+6, (char*)pAll->z, pAll->n);
+ sqlite3ChangeCookie(db, v, iDb);
+ sqlite3VdbeAddOp(v, OP_Close, 0, 0);
+ sqlite3VdbeOp3(v, OP_ParseSchema, iDb, 0, sqlite3MPrintf(
+ db, "type='trigger' AND name='%q'", pTrig->name), P3_DYNAMIC
+ );
+ }
+
+ if( db->init.busy ){
+ int n;
+ Table *pTab;
+ Trigger *pDel;
+ pDel = (Trigger*)sqlite3HashInsert(&db->aDb[iDb].pSchema->trigHash,
+ pTrig->name, strlen(pTrig->name), pTrig);
+ if( pDel ){
+ assert( pDel==pTrig );
+ db->mallocFailed = 1;
+ goto triggerfinish_cleanup;
+ }
+ n = strlen(pTrig->table) + 1;
+ pTab = (Table*)sqlite3HashFind(&pTrig->pTabSchema->tblHash, pTrig->table, n);
+ assert( pTab!=0 );
+ pTrig->pNext = pTab->pTrigger;
+ pTab->pTrigger = pTrig;
+ pTrig = 0;
+ }
+
+triggerfinish_cleanup:
+ sqlite3DeleteTrigger(pTrig);
+ assert( !pParse->pNewTrigger );
+ sqlite3DeleteTriggerStep(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 sqlite3_malloc(). 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 sqlite3_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 sqlite3_exec() call returns.
+*/
+static void sqlitePersistTriggerStep(sqlite3 *db, TriggerStep *p){
+ if( p->target.z ){
+ p->target.z = (u8*)sqlite3DbStrNDup(db, (char*)p->target.z, p->target.n);
+ p->target.dyn = 1;
+ }
+ if( p->pSelect ){
+ Select *pNew = sqlite3SelectDup(db, p->pSelect);
+ sqlite3SelectDelete(p->pSelect);
+ p->pSelect = pNew;
+ }
+ if( p->pWhere ){
+ Expr *pNew = sqlite3ExprDup(db, p->pWhere);
+ sqlite3ExprDelete(p->pWhere);
+ p->pWhere = pNew;
+ }
+ if( p->pExprList ){
+ ExprList *pNew = sqlite3ExprListDup(db, p->pExprList);
+ sqlite3ExprListDelete(p->pExprList);
+ p->pExprList = pNew;
+ }
+ if( p->pIdList ){
+ IdList *pNew = sqlite3IdListDup(db, p->pIdList);
+ sqlite3IdListDelete(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 *sqlite3TriggerSelectStep(sqlite3 *db, Select *pSelect){
+ TriggerStep *pTriggerStep = (TriggerStep*)sqlite3DbMallocZero(db, sizeof(TriggerStep));
+ if( pTriggerStep==0 ) {
+ sqlite3SelectDelete(pSelect);
+ return 0;
+ }
+
+ pTriggerStep->op = TK_SELECT;
+ pTriggerStep->pSelect = pSelect;
+ pTriggerStep->orconf = OE_Default;
+ sqlitePersistTriggerStep(db, 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 *sqlite3TriggerInsertStep(
+ sqlite3 *db, /* The database connection */
+ 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;
+
+ assert(pEList == 0 || pSelect == 0);
+ assert(pEList != 0 || pSelect != 0 || db->mallocFailed);
+
+ pTriggerStep = (TriggerStep*)sqlite3DbMallocZero(db, sizeof(TriggerStep));
+ if( pTriggerStep ){
+ pTriggerStep->op = TK_INSERT;
+ pTriggerStep->pSelect = pSelect;
+ pTriggerStep->target = *pTableName;
+ pTriggerStep->pIdList = pColumn;
+ pTriggerStep->pExprList = pEList;
+ pTriggerStep->orconf = orconf;
+ sqlitePersistTriggerStep(db, pTriggerStep);
+ }else{
+ sqlite3IdListDelete(pColumn);
+ sqlite3ExprListDelete(pEList);
+ sqlite3SelectDelete(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(
+ sqlite3 *db, /* The database connection */
+ 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 = (TriggerStep*)sqlite3DbMallocZero(db, sizeof(TriggerStep));
+ if( pTriggerStep==0 ){
+ sqlite3ExprListDelete(pEList);
+ sqlite3ExprDelete(pWhere);
+ return 0;
+ }
+
+ pTriggerStep->op = TK_UPDATE;
+ pTriggerStep->target = *pTableName;
+ pTriggerStep->pExprList = pEList;
+ pTriggerStep->pWhere = pWhere;
+ pTriggerStep->orconf = orconf;
+ sqlitePersistTriggerStep(db, 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 *sqlite3TriggerDeleteStep(
+ sqlite3 *db, /* Database connection */
+ Token *pTableName, /* The table from which rows are deleted */
+ Expr *pWhere /* The WHERE clause */
+){
+ TriggerStep *pTriggerStep = (TriggerStep*)sqlite3DbMallocZero(db, sizeof(TriggerStep));
+ if( pTriggerStep==0 ){
+ sqlite3ExprDelete(pWhere);
+ return 0;
+ }
+
+ pTriggerStep->op = TK_DELETE;
+ pTriggerStep->target = *pTableName;
+ pTriggerStep->pWhere = pWhere;
+ pTriggerStep->orconf = OE_Default;
+ sqlitePersistTriggerStep(db, pTriggerStep);
+
+ return pTriggerStep;
+}
+
+/*
+** Recursively delete a Trigger structure
+*/
+void sqlite3DeleteTrigger(Trigger *pTrigger){
+ if( pTrigger==0 ) return;
+ sqlite3DeleteTriggerStep(pTrigger->step_list);
+ sqlite3_free(pTrigger->name);
+ sqlite3_free(pTrigger->table);
+ sqlite3ExprDelete(pTrigger->pWhen);
+ sqlite3IdListDelete(pTrigger->pColumns);
+ if( pTrigger->nameToken.dyn ) sqlite3_free((char*)pTrigger->nameToken.z);
+ sqlite3_free(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;
+ int nName;
+ 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;
+ nName = strlen(zName);
+ for(i=OMIT_TEMPDB; i<db->nDb; i++){
+ int j = (i<2) ? i^1 : i; /* Search TEMP before MAIN */
+ if( zDb && sqlite3StrICmp(db->aDb[j].zName, zDb) ) continue;
+ pTrigger = (Trigger*)sqlite3HashFind(&(db->aDb[j].pSchema->trigHash), zName, nName);
+ if( pTrigger ) break;
+ }
+ if( !pTrigger ){
+ if( !noErr ){
+ sqlite3ErrorMsg(pParse, "no such trigger: %S", pName, 0);
+ }
+ goto drop_trigger_cleanup;
+ }
+ sqlite3DropTriggerPtr(pParse, pTrigger);
+
+drop_trigger_cleanup:
+ sqlite3SrcListDelete(pName);
+}
+
+/*
+** Return a pointer to the Table structure for the table that a trigger
+** is set on.
+*/
+static Table *tableOfTrigger(Trigger *pTrigger){
+ int n = strlen(pTrigger->table) + 1;
+ return (Table*)sqlite3HashFind(&pTrigger->pTabSchema->tblHash, pTrigger->table, n);
+}
+
+
+/*
+** 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->name, 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 VdbeOpList dropTrigger[] = {
+ { OP_Rewind, 0, ADDR(9), 0},
+ { OP_String8, 0, 0, 0}, /* 1 */
+ { OP_Column, 0, 1, 0},
+ { OP_Ne, 0, ADDR(8), 0},
+ { OP_String8, 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 */
+ };
+
+ sqlite3BeginWriteOperation(pParse, 0, iDb);
+ sqlite3OpenMasterTable(pParse, iDb);
+ base = sqlite3VdbeAddOpList(v, ArraySize(dropTrigger), dropTrigger);
+ sqlite3VdbeChangeP3(v, base+1, pTrigger->name, 0);
+ sqlite3ChangeCookie(db, v, iDb);
+ sqlite3VdbeAddOp(v, OP_Close, 0, 0);
+ sqlite3VdbeOp3(v, OP_DropTrigger, iDb, 0, pTrigger->name, 0);
+ }
+}
+
+/*
+** Remove a trigger from the hash tables of the sqlite* pointer.
+*/
+void sqlite3UnlinkAndDeleteTrigger(sqlite3 *db, int iDb, const char *zName){
+ Trigger *pTrigger;
+ int nName = strlen(zName);
+ pTrigger = (Trigger*)sqlite3HashInsert(&(db->aDb[iDb].pSchema->trigHash),
+ zName, nName, 0);
+ if( pTrigger ){
+ Table *pTable = tableOfTrigger(pTrigger);
+ assert( pTable!=0 );
+ 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);
+ }
+ sqlite3DeleteTrigger(pTrigger);
+ db->flags |= SQLITE_InternChanges;
+ }
+}
+
+/*
+** 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( sqlite3IdListIndex(pIdList, pEList->a[e].zName)>=0 ) return 1;
+ }
+ return 0;
+}
+
+/*
+** Return a bit vector to indicate what kind of triggers exist for operation
+** "op" on table pTab. If pChanges is not NULL then it is a list of columns
+** that are being updated. Triggers only match if the ON clause of the
+** trigger definition overlaps the set of columns being updated.
+**
+** The returned bit vector is some combination of TRIGGER_BEFORE and
+** TRIGGER_AFTER.
+*/
+int sqlite3TriggersExist(
+ Parse *pParse, /* Used to check for recursive triggers */
+ 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 */
+){
+ Trigger *pTrigger;
+ int mask = 0;
+
+ pTrigger = IsVirtual(pTab) ? 0 : pTab->pTrigger;
+ while( pTrigger ){
+ if( pTrigger->op==op && checkColumnOverLap(pTrigger->pColumns, pChanges) ){
+ mask |= pTrigger->tr_tm;
+ }
+ pTrigger = pTrigger->pNext;
+ }
+ return mask;
+}
+
+/*
+** 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 = sqlite3SchemaToIndex(pParse->db, pStep->pTrig->pSchema);
+ if( iDb==0 || iDb>=2 ){
+ assert( iDb<pParse->db->nDb );
+ sDb.z = (u8*)pParse->db->aDb[iDb].zName;
+ sDb.n = strlen((char*)sDb.z);
+ pSrc = sqlite3SrcListAppend(pParse->db, 0, &sDb, &pStep->target);
+ } else {
+ pSrc = sqlite3SrcListAppend(pParse->db, 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;
+ Vdbe *v = pParse->pVdbe;
+ sqlite3 *db = pParse->db;
+
+ assert( pTriggerStep!=0 );
+ assert( v!=0 );
+ sqlite3VdbeAddOp(v, OP_ContextPush, 0, 0);
+ VdbeComment((v, "# begin trigger %s", pStepList->pTrig->name));
+ while( pTriggerStep ){
+ orconf = (orconfin == OE_Default)?pTriggerStep->orconf:orconfin;
+ pParse->trigStack->orconf = orconf;
+ switch( pTriggerStep->op ){
+ case TK_SELECT: {
+ Select *ss = sqlite3SelectDup(db, pTriggerStep->pSelect);
+ if( ss ){
+ sqlite3SelectResolve(pParse, ss, 0);
+ sqlite3Select(pParse, ss, SRT_Discard, 0, 0, 0, 0, 0);
+ sqlite3SelectDelete(ss);
+ }
+ break;
+ }
+ case TK_UPDATE: {
+ SrcList *pSrc;
+ pSrc = targetSrcList(pParse, pTriggerStep);
+ sqlite3VdbeAddOp(v, OP_ResetCount, 0, 0);
+ sqlite3Update(pParse, pSrc,
+ sqlite3ExprListDup(db, pTriggerStep->pExprList),
+ sqlite3ExprDup(db, pTriggerStep->pWhere), orconf);
+ sqlite3VdbeAddOp(v, OP_ResetCount, 1, 0);
+ break;
+ }
+ case TK_INSERT: {
+ SrcList *pSrc;
+ pSrc = targetSrcList(pParse, pTriggerStep);
+ sqlite3VdbeAddOp(v, OP_ResetCount, 0, 0);
+ sqlite3Insert(pParse, pSrc,
+ sqlite3ExprListDup(db, pTriggerStep->pExprList),
+ sqlite3SelectDup(db, pTriggerStep->pSelect),
+ sqlite3IdListDup(db, pTriggerStep->pIdList), orconf);
+ sqlite3VdbeAddOp(v, OP_ResetCount, 1, 0);
+ break;
+ }
+ case TK_DELETE: {
+ SrcList *pSrc;
+ sqlite3VdbeAddOp(v, OP_ResetCount, 0, 0);
+ pSrc = targetSrcList(pParse, pTriggerStep);
+ sqlite3DeleteFrom(pParse, pSrc,
+ sqlite3ExprDup(db, pTriggerStep->pWhere));
+ sqlite3VdbeAddOp(v, OP_ResetCount, 1, 0);
+ break;
+ }
+ default:
+ assert(0);
+ }
+ pTriggerStep = pTriggerStep->pNext;
+ }
+ sqlite3VdbeAddOp(v, OP_ContextPop, 0, 0);
+ VdbeComment((v, "# end trigger %s", pStepList->pTrig->name));
+
+ 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 sqlite3CodeRowTrigger(
+ 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 TRIGGER_BEFORE, TRIGGER_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 *p;
+ TriggerStack trigStackEntry;
+
+ assert(op == TK_UPDATE || op == TK_INSERT || op == TK_DELETE);
+ assert(tr_tm == TRIGGER_BEFORE || tr_tm == TRIGGER_AFTER );
+
+ assert(newIdx != -1 || oldIdx != -1);
+
+ for(p=pTab->pTrigger; p; p=p->pNext){
+ int fire_this = 0;
+ sqlite3 *db = pParse->db;
+
+ /* Determine whether we should code this trigger */
+ if(
+ p->op==op &&
+ p->tr_tm==tr_tm &&
+ (p->pSchema==p->pTabSchema || p->pSchema==db->aDb[1].pSchema) &&
+ (op!=TK_UPDATE||!p->pColumns||checkColumnOverLap(p->pColumns,pChanges))
+ ){
+ TriggerStack *pS; /* Pointer to trigger-stack entry */
+ for(pS=pParse->trigStack; pS && p!=pS->pTrigger; pS=pS->pNext){}
+ if( !pS ){
+ fire_this = 1;
+ }
+#if 0 /* Give no warning for recursive triggers. Just do not do them */
+ else{
+ sqlite3ErrorMsg(pParse, "recursive triggers not supported (%s)",
+ p->name);
+ return SQLITE_ERROR;
+ }
+#endif
+ }
+
+ if( fire_this ){
+ int endTrigger;
+ Expr * whenExpr;
+ AuthContext sContext;
+ NameContext sNC;
+
+ memset(&sNC, 0, sizeof(sNC));
+ sNC.pParse = pParse;
+
+ /* Push an entry on to the trigger stack */
+ trigStackEntry.pTrigger = p;
+ trigStackEntry.newIdx = newIdx;
+ trigStackEntry.oldIdx = oldIdx;
+ trigStackEntry.pTab = pTab;
+ trigStackEntry.pNext = pParse->trigStack;
+ trigStackEntry.ignoreJump = ignoreJump;
+ pParse->trigStack = &trigStackEntry;
+ sqlite3AuthContextPush(pParse, &sContext, p->name);
+
+ /* code the WHEN clause */
+ endTrigger = sqlite3VdbeMakeLabel(pParse->pVdbe);
+ whenExpr = sqlite3ExprDup(db, p->pWhen);
+ if( db->mallocFailed || sqlite3ExprResolveNames(&sNC, whenExpr) ){
+ pParse->trigStack = trigStackEntry.pNext;
+ sqlite3ExprDelete(whenExpr);
+ return 1;
+ }
+ sqlite3ExprIfFalse(pParse, whenExpr, endTrigger, 1);
+ sqlite3ExprDelete(whenExpr);
+
+ codeTriggerProgram(pParse, p->step_list, orconf);
+
+ /* Pop the entry off the trigger stack */
+ pParse->trigStack = trigStackEntry.pNext;
+ sqlite3AuthContextPop(&sContext);
+
+ sqlite3VdbeResolveLabel(pParse->pVdbe, endTrigger);
+ }
+ }
+ return 0;
+}
+#endif /* !defined(SQLITE_OMIT_TRIGGER) */