ds@1952: /*
ds@1952: **
ds@1952: ** The author disclaims copyright to this source code.  In place of
ds@1952: ** a legal notice, here is a blessing:
ds@1952: **
ds@1952: **    May you do good and not evil.
ds@1952: **    May you find forgiveness for yourself and forgive others.
ds@1952: **    May you share freely, never taking more than you give.
ds@1952: **
ds@1952: *************************************************************************
ds@1952: *
ds@1952: */
ds@1952: #include "sqliteInt.h"
ds@1952: 
ds@1952: #ifndef SQLITE_OMIT_TRIGGER
ds@1952: /*
ds@1952: ** Delete a linked list of TriggerStep structures.
ds@1952: */
ds@1952: void sqlite3DeleteTriggerStep(TriggerStep *pTriggerStep){
ds@1952:   while( pTriggerStep ){
ds@1952:     TriggerStep * pTmp = pTriggerStep;
ds@1952:     pTriggerStep = pTriggerStep->pNext;
ds@1952: 
ds@1952:     if( pTmp->target.dyn ) sqlite3_free((char*)pTmp->target.z);
ds@1952:     sqlite3ExprDelete(pTmp->pWhere);
ds@1952:     sqlite3ExprListDelete(pTmp->pExprList);
ds@1952:     sqlite3SelectDelete(pTmp->pSelect);
ds@1952:     sqlite3IdListDelete(pTmp->pIdList);
ds@1952: 
ds@1952:     sqlite3_free(pTmp);
ds@1952:   }
ds@1952: }
ds@1952: 
ds@1952: /*
ds@1952: ** This is called by the parser when it sees a CREATE TRIGGER statement
ds@1952: ** up to the point of the BEGIN before the trigger actions.  A Trigger
ds@1952: ** structure is generated based on the information available and stored
ds@1952: ** in pParse->pNewTrigger.  After the trigger actions have been parsed, the
ds@1952: ** sqlite3FinishTrigger() function is called to complete the trigger
ds@1952: ** construction process.
ds@1952: */
ds@1952: void sqlite3BeginTrigger(
ds@1952:   Parse *pParse,      /* The parse context of the CREATE TRIGGER statement */
ds@1952:   Token *pName1,      /* The name of the trigger */
ds@1952:   Token *pName2,      /* The name of the trigger */
ds@1952:   int tr_tm,          /* One of TK_BEFORE, TK_AFTER, TK_INSTEAD */
ds@1952:   int op,             /* One of TK_INSERT, TK_UPDATE, TK_DELETE */
ds@1952:   IdList *pColumns,   /* column list if this is an UPDATE OF trigger */
ds@1952:   SrcList *pTableName,/* The name of the table/view the trigger applies to */
ds@1952:   Expr *pWhen,        /* WHEN clause */
ds@1952:   int isTemp,         /* True if the TEMPORARY keyword is present */
ds@1952:   int noErr           /* Suppress errors if the trigger already exists */
ds@1952: ){
ds@1952:   Trigger *pTrigger = 0;
ds@1952:   Table *pTab;
ds@1952:   char *zName = 0;        /* Name of the trigger */
ds@1952:   sqlite3 *db = pParse->db;
ds@1952:   int iDb;                /* The database to store the trigger in */
ds@1952:   Token *pName;           /* The unqualified db name */
ds@1952:   DbFixer sFix;
ds@1952:   int iTabDb;
ds@1952: 
ds@1952:   assert( pName1!=0 );   /* pName1->z might be NULL, but not pName1 itself */
ds@1952:   assert( pName2!=0 );
ds@1952:   if( isTemp ){
ds@1952:     /* If TEMP was specified, then the trigger name may not be qualified. */
ds@1952:     if( pName2->n>0 ){
ds@1952:       sqlite3ErrorMsg(pParse, "temporary trigger may not have qualified name");
ds@1952:       goto trigger_cleanup;
ds@1952:     }
ds@1952:     iDb = 1;
ds@1952:     pName = pName1;
ds@1952:   }else{
ds@1952:     /* Figure out the db that the the trigger will be created in */
ds@1952:     iDb = sqlite3TwoPartName(pParse, pName1, pName2, &pName);
ds@1952:     if( iDb<0 ){
ds@1952:       goto trigger_cleanup;
ds@1952:     }
ds@1952:   }
ds@1952: 
ds@1952:   /* If the trigger name was unqualified, and the table is a temp table,
ds@1952:   ** then set iDb to 1 to create the trigger in the temporary database.
ds@1952:   ** If sqlite3SrcListLookup() returns 0, indicating the table does not
ds@1952:   ** exist, the error is caught by the block below.
ds@1952:   */
ds@1952:   if( !pTableName || db->mallocFailed ){
ds@1952:     goto trigger_cleanup;
ds@1952:   }
ds@1952:   pTab = sqlite3SrcListLookup(pParse, pTableName);
ds@1952:   if( pName2->n==0 && pTab && pTab->pSchema==db->aDb[1].pSchema ){
ds@1952:     iDb = 1;
ds@1952:   }
ds@1952: 
ds@1952:   /* Ensure the table name matches database name and that the table exists */
ds@1952:   if( db->mallocFailed ) goto trigger_cleanup;
ds@1952:   assert( pTableName->nSrc==1 );
ds@1952:   if( sqlite3FixInit(&sFix, pParse, iDb, "trigger", pName) && 
ds@1952:       sqlite3FixSrcList(&sFix, pTableName) ){
ds@1952:     goto trigger_cleanup;
ds@1952:   }
ds@1952:   pTab = sqlite3SrcListLookup(pParse, pTableName);
ds@1952:   if( !pTab ){
ds@1952:     /* The table does not exist. */
ds@1952:     goto trigger_cleanup;
ds@1952:   }
ds@1952:   if( IsVirtual(pTab) ){
ds@1952:     sqlite3ErrorMsg(pParse, "cannot create triggers on virtual tables");
ds@1952:     goto trigger_cleanup;
ds@1952:   }
ds@1952: 
ds@1952:   /* Check that the trigger name is not reserved and that no trigger of the
ds@1952:   ** specified name exists */
ds@1952:   zName = sqlite3NameFromToken(db, pName);
ds@1952:   if( !zName || SQLITE_OK!=sqlite3CheckObjectName(pParse, zName) ){
ds@1952:     goto trigger_cleanup;
ds@1952:   }
ds@1952:   if( sqlite3HashFind(&(db->aDb[iDb].pSchema->trigHash), zName,strlen(zName)) ){
ds@1952:     if( !noErr ){
ds@1952:       sqlite3ErrorMsg(pParse, "trigger %T already exists", pName);
ds@1952:     }
ds@1952:     goto trigger_cleanup;
ds@1952:   }
ds@1952: 
ds@1952:   /* Do not create a trigger on a system table */
ds@1952:   if( sqlite3StrNICmp(pTab->zName, "sqlite_", 7)==0 ){
ds@1952:     sqlite3ErrorMsg(pParse, "cannot create trigger on system table");
ds@1952:     pParse->nErr++;
ds@1952:     goto trigger_cleanup;
ds@1952:   }
ds@1952: 
ds@1952:   /* INSTEAD of triggers are only for views and views only support INSTEAD
ds@1952:   ** of triggers.
ds@1952:   */
ds@1952:   if( pTab->pSelect && tr_tm!=TK_INSTEAD ){
ds@1952:     sqlite3ErrorMsg(pParse, "cannot create %s trigger on view: %S", 
ds@1952:         (tr_tm == TK_BEFORE)?"BEFORE":"AFTER", pTableName, 0);
ds@1952:     goto trigger_cleanup;
ds@1952:   }
ds@1952:   if( !pTab->pSelect && tr_tm==TK_INSTEAD ){
ds@1952:     sqlite3ErrorMsg(pParse, "cannot create INSTEAD OF"
ds@1952:         " trigger on table: %S", pTableName, 0);
ds@1952:     goto trigger_cleanup;
ds@1952:   }
ds@1952:   iTabDb = sqlite3SchemaToIndex(db, pTab->pSchema);
ds@1952: 
ds@1952: #ifndef SQLITE_OMIT_AUTHORIZATION
ds@1952:   {
ds@1952:     int code = SQLITE_CREATE_TRIGGER;
ds@1952:     const char *zDb = db->aDb[iTabDb].zName;
ds@1952:     const char *zDbTrig = isTemp ? db->aDb[1].zName : zDb;
ds@1952:     if( iTabDb==1 || isTemp ) code = SQLITE_CREATE_TEMP_TRIGGER;
ds@1952:     if( sqlite3AuthCheck(pParse, code, zName, pTab->zName, zDbTrig) ){
ds@1952:       goto trigger_cleanup;
ds@1952:     }
ds@1952:     if( sqlite3AuthCheck(pParse, SQLITE_INSERT, SCHEMA_TABLE(iTabDb),0,zDb)){
ds@1952:       goto trigger_cleanup;
ds@1952:     }
ds@1952:   }
ds@1952: #endif
ds@1952: 
ds@1952:   /* INSTEAD OF triggers can only appear on views and BEFORE triggers
ds@1952:   ** cannot appear on views.  So we might as well translate every
ds@1952:   ** INSTEAD OF trigger into a BEFORE trigger.  It simplifies code
ds@1952:   ** elsewhere.
ds@1952:   */
ds@1952:   if (tr_tm == TK_INSTEAD){
ds@1952:     tr_tm = TK_BEFORE;
ds@1952:   }
ds@1952: 
ds@1952:   /* Build the Trigger object */
ds@1952:   pTrigger = (Trigger*)sqlite3DbMallocZero(db, sizeof(Trigger));
ds@1952:   if( pTrigger==0 ) goto trigger_cleanup;
ds@1952:   pTrigger->name = zName;
ds@1952:   zName = 0;
ds@1952:   pTrigger->table = sqlite3DbStrDup(db, pTableName->a[0].zName);
ds@1952:   pTrigger->pSchema = db->aDb[iDb].pSchema;
ds@1952:   pTrigger->pTabSchema = pTab->pSchema;
ds@1952:   pTrigger->op = op;
ds@1952:   pTrigger->tr_tm = tr_tm==TK_BEFORE ? TRIGGER_BEFORE : TRIGGER_AFTER;
ds@1952:   pTrigger->pWhen = sqlite3ExprDup(db, pWhen);
ds@1952:   pTrigger->pColumns = sqlite3IdListDup(db, pColumns);
ds@1952:   sqlite3TokenCopy(db, &pTrigger->nameToken,pName);
ds@1952:   assert( pParse->pNewTrigger==0 );
ds@1952:   pParse->pNewTrigger = pTrigger;
ds@1952: 
ds@1952: trigger_cleanup:
ds@1952:   sqlite3_free(zName);
ds@1952:   sqlite3SrcListDelete(pTableName);
ds@1952:   sqlite3IdListDelete(pColumns);
ds@1952:   sqlite3ExprDelete(pWhen);
ds@1952:   if( !pParse->pNewTrigger ){
ds@1952:     sqlite3DeleteTrigger(pTrigger);
ds@1952:   }else{
ds@1952:     assert( pParse->pNewTrigger==pTrigger );
ds@1952:   }
ds@1952: }
ds@1952: 
ds@1952: /*
ds@1952: ** This routine is called after all of the trigger actions have been parsed
ds@1952: ** in order to complete the process of building the trigger.
ds@1952: */
ds@1952: void sqlite3FinishTrigger(
ds@1952:   Parse *pParse,          /* Parser context */
ds@1952:   TriggerStep *pStepList, /* The triggered program */
ds@1952:   Token *pAll             /* Token that describes the complete CREATE TRIGGER */
ds@1952: ){
ds@1952:   Trigger *pTrig = 0;     /* The trigger whose construction is finishing up */
ds@1952:   sqlite3 *db = pParse->db;  /* The database */
ds@1952:   DbFixer sFix;
ds@1952:   int iDb;                   /* Database containing the trigger */
ds@1952: 
ds@1952:   pTrig = pParse->pNewTrigger;
ds@1952:   pParse->pNewTrigger = 0;
ds@1952:   if( pParse->nErr || !pTrig ) goto triggerfinish_cleanup;
ds@1952:   iDb = sqlite3SchemaToIndex(pParse->db, pTrig->pSchema);
ds@1952:   pTrig->step_list = pStepList;
ds@1952:   while( pStepList ){
ds@1952:     pStepList->pTrig = pTrig;
ds@1952:     pStepList = pStepList->pNext;
ds@1952:   }
ds@1952:   if( sqlite3FixInit(&sFix, pParse, iDb, "trigger", &pTrig->nameToken) 
ds@1952:           && sqlite3FixTriggerStep(&sFix, pTrig->step_list) ){
ds@1952:     goto triggerfinish_cleanup;
ds@1952:   }
ds@1952: 
ds@1952:   /* if we are not initializing, and this trigger is not on a TEMP table, 
ds@1952:   ** build the sqlite_master entry
ds@1952:   */
ds@1952:   if( !db->init.busy ){
ds@1952:     static const VdbeOpList insertTrig[] = {
ds@1952:       { OP_NewRowid,   0, 0,  0          },
ds@1952:       { OP_String8,    0, 0,  "trigger"  },
ds@1952:       { OP_String8,    0, 0,  0          },  /* 2: trigger name */
ds@1952:       { OP_String8,    0, 0,  0          },  /* 3: table name */
ds@1952:       { OP_Integer,    0, 0,  0          },
ds@1952:       { OP_String8,    0, 0,  "CREATE TRIGGER "},
ds@1952:       { OP_String8,    0, 0,  0          },  /* 6: SQL */
ds@1952:       { OP_Concat,     0, 0,  0          }, 
ds@1952:       { OP_MakeRecord, 5, 0,  "aaada"    },
ds@1952:       { OP_Insert,     0, 0,  0          },
ds@1952:     };
ds@1952:     int addr;
ds@1952:     Vdbe *v;
ds@1952: 
ds@1952:     /* Make an entry in the sqlite_master table */
ds@1952:     v = sqlite3GetVdbe(pParse);
ds@1952:     if( v==0 ) goto triggerfinish_cleanup;
ds@1952:     sqlite3BeginWriteOperation(pParse, 0, iDb);
ds@1952:     sqlite3OpenMasterTable(pParse, iDb);
ds@1952:     addr = sqlite3VdbeAddOpList(v, ArraySize(insertTrig), insertTrig);
ds@1952:     sqlite3VdbeChangeP3(v, addr+2, pTrig->name, 0); 
ds@1952:     sqlite3VdbeChangeP3(v, addr+3, pTrig->table, 0); 
ds@1952:     sqlite3VdbeChangeP3(v, addr+6, (char*)pAll->z, pAll->n);
ds@1952:     sqlite3ChangeCookie(db, v, iDb);
ds@1952:     sqlite3VdbeAddOp(v, OP_Close, 0, 0);
ds@1952:     sqlite3VdbeOp3(v, OP_ParseSchema, iDb, 0, sqlite3MPrintf(
ds@1952:         db, "type='trigger' AND name='%q'", pTrig->name), P3_DYNAMIC
ds@1952:     );
ds@1952:   }
ds@1952: 
ds@1952:   if( db->init.busy ){
ds@1952:     int n;
ds@1952:     Table *pTab;
ds@1952:     Trigger *pDel;
ds@1952:     pDel = sqlite3HashInsert(&db->aDb[iDb].pSchema->trigHash, 
ds@1952:                      pTrig->name, strlen(pTrig->name), pTrig);
ds@1952:     if( pDel ){
ds@1952:       assert( pDel==pTrig );
ds@1952:       db->mallocFailed = 1;
ds@1952:       goto triggerfinish_cleanup;
ds@1952:     }
ds@1952:     n = strlen(pTrig->table) + 1;
ds@1952:     pTab = sqlite3HashFind(&pTrig->pTabSchema->tblHash, pTrig->table, n);
ds@1952:     assert( pTab!=0 );
ds@1952:     pTrig->pNext = pTab->pTrigger;
ds@1952:     pTab->pTrigger = pTrig;
ds@1952:     pTrig = 0;
ds@1952:   }
ds@1952: 
ds@1952: triggerfinish_cleanup:
ds@1952:   sqlite3DeleteTrigger(pTrig);
ds@1952:   assert( !pParse->pNewTrigger );
ds@1952:   sqlite3DeleteTriggerStep(pStepList);
ds@1952: }
ds@1952: 
ds@1952: /*
ds@1952: ** Make a copy of all components of the given trigger step.  This has
ds@1952: ** the effect of copying all Expr.token.z values into memory obtained
ds@1952: ** from sqlite3_malloc().  As initially created, the Expr.token.z values
ds@1952: ** all point to the input string that was fed to the parser.  But that
ds@1952: ** string is ephemeral - it will go away as soon as the sqlite3_exec()
ds@1952: ** call that started the parser exits.  This routine makes a persistent
ds@1952: ** copy of all the Expr.token.z strings so that the TriggerStep structure
ds@1952: ** will be valid even after the sqlite3_exec() call returns.
ds@1952: */
ds@1952: static void sqlitePersistTriggerStep(sqlite3 *db, TriggerStep *p){
ds@1952:   if( p->target.z ){
ds@1952:     p->target.z = (u8*)sqlite3DbStrNDup(db, (char*)p->target.z, p->target.n);
ds@1952:     p->target.dyn = 1;
ds@1952:   }
ds@1952:   if( p->pSelect ){
ds@1952:     Select *pNew = sqlite3SelectDup(db, p->pSelect);
ds@1952:     sqlite3SelectDelete(p->pSelect);
ds@1952:     p->pSelect = pNew;
ds@1952:   }
ds@1952:   if( p->pWhere ){
ds@1952:     Expr *pNew = sqlite3ExprDup(db, p->pWhere);
ds@1952:     sqlite3ExprDelete(p->pWhere);
ds@1952:     p->pWhere = pNew;
ds@1952:   }
ds@1952:   if( p->pExprList ){
ds@1952:     ExprList *pNew = sqlite3ExprListDup(db, p->pExprList);
ds@1952:     sqlite3ExprListDelete(p->pExprList);
ds@1952:     p->pExprList = pNew;
ds@1952:   }
ds@1952:   if( p->pIdList ){
ds@1952:     IdList *pNew = sqlite3IdListDup(db, p->pIdList);
ds@1952:     sqlite3IdListDelete(p->pIdList);
ds@1952:     p->pIdList = pNew;
ds@1952:   }
ds@1952: }
ds@1952: 
ds@1952: /*
ds@1952: ** Turn a SELECT statement (that the pSelect parameter points to) into
ds@1952: ** a trigger step.  Return a pointer to a TriggerStep structure.
ds@1952: **
ds@1952: ** The parser calls this routine when it finds a SELECT statement in
ds@1952: ** body of a TRIGGER.  
ds@1952: */
ds@1952: TriggerStep *sqlite3TriggerSelectStep(sqlite3 *db, Select *pSelect){
ds@1952:   TriggerStep *pTriggerStep = sqlite3DbMallocZero(db, sizeof(TriggerStep));
ds@1952:   if( pTriggerStep==0 ) {
ds@1952:     sqlite3SelectDelete(pSelect);
ds@1952:     return 0;
ds@1952:   }
ds@1952: 
ds@1952:   pTriggerStep->op = TK_SELECT;
ds@1952:   pTriggerStep->pSelect = pSelect;
ds@1952:   pTriggerStep->orconf = OE_Default;
ds@1952:   sqlitePersistTriggerStep(db, pTriggerStep);
ds@1952: 
ds@1952:   return pTriggerStep;
ds@1952: }
ds@1952: 
ds@1952: /*
ds@1952: ** Build a trigger step out of an INSERT statement.  Return a pointer
ds@1952: ** to the new trigger step.
ds@1952: **
ds@1952: ** The parser calls this routine when it sees an INSERT inside the
ds@1952: ** body of a trigger.
ds@1952: */
ds@1952: TriggerStep *sqlite3TriggerInsertStep(
ds@1952:   sqlite3 *db,        /* The database connection */
ds@1952:   Token *pTableName,  /* Name of the table into which we insert */
ds@1952:   IdList *pColumn,    /* List of columns in pTableName to insert into */
ds@1952:   ExprList *pEList,   /* The VALUE clause: a list of values to be inserted */
ds@1952:   Select *pSelect,    /* A SELECT statement that supplies values */
ds@1952:   int orconf          /* The conflict algorithm (OE_Abort, OE_Replace, etc.) */
ds@1952: ){
ds@1952:   TriggerStep *pTriggerStep;
ds@1952: 
ds@1952:   assert(pEList == 0 || pSelect == 0);
ds@1952:   assert(pEList != 0 || pSelect != 0 || db->mallocFailed);
ds@1952: 
ds@1952:   pTriggerStep = sqlite3DbMallocZero(db, sizeof(TriggerStep));
ds@1952:   if( pTriggerStep ){
ds@1952:     pTriggerStep->op = TK_INSERT;
ds@1952:     pTriggerStep->pSelect = pSelect;
ds@1952:     pTriggerStep->target  = *pTableName;
ds@1952:     pTriggerStep->pIdList = pColumn;
ds@1952:     pTriggerStep->pExprList = pEList;
ds@1952:     pTriggerStep->orconf = orconf;
ds@1952:     sqlitePersistTriggerStep(db, pTriggerStep);
ds@1952:   }else{
ds@1952:     sqlite3IdListDelete(pColumn);
ds@1952:     sqlite3ExprListDelete(pEList);
ds@1952:     sqlite3SelectDelete(pSelect);
ds@1952:   }
ds@1952: 
ds@1952:   return pTriggerStep;
ds@1952: }
ds@1952: 
ds@1952: /*
ds@1952: ** Construct a trigger step that implements an UPDATE statement and return
ds@1952: ** a pointer to that trigger step.  The parser calls this routine when it
ds@1952: ** sees an UPDATE statement inside the body of a CREATE TRIGGER.
ds@1952: */
ds@1952: TriggerStep *sqlite3TriggerUpdateStep(
ds@1952:   sqlite3 *db,         /* The database connection */
ds@1952:   Token *pTableName,   /* Name of the table to be updated */
ds@1952:   ExprList *pEList,    /* The SET clause: list of column and new values */
ds@1952:   Expr *pWhere,        /* The WHERE clause */
ds@1952:   int orconf           /* The conflict algorithm. (OE_Abort, OE_Ignore, etc) */
ds@1952: ){
ds@1952:   TriggerStep *pTriggerStep = sqlite3DbMallocZero(db, sizeof(TriggerStep));
ds@1952:   if( pTriggerStep==0 ){
ds@1952:      sqlite3ExprListDelete(pEList);
ds@1952:      sqlite3ExprDelete(pWhere);
ds@1952:      return 0;
ds@1952:   }
ds@1952: 
ds@1952:   pTriggerStep->op = TK_UPDATE;
ds@1952:   pTriggerStep->target  = *pTableName;
ds@1952:   pTriggerStep->pExprList = pEList;
ds@1952:   pTriggerStep->pWhere = pWhere;
ds@1952:   pTriggerStep->orconf = orconf;
ds@1952:   sqlitePersistTriggerStep(db, pTriggerStep);
ds@1952: 
ds@1952:   return pTriggerStep;
ds@1952: }
ds@1952: 
ds@1952: /*
ds@1952: ** Construct a trigger step that implements a DELETE statement and return
ds@1952: ** a pointer to that trigger step.  The parser calls this routine when it
ds@1952: ** sees a DELETE statement inside the body of a CREATE TRIGGER.
ds@1952: */
ds@1952: TriggerStep *sqlite3TriggerDeleteStep(
ds@1952:   sqlite3 *db,            /* Database connection */
ds@1952:   Token *pTableName,      /* The table from which rows are deleted */
ds@1952:   Expr *pWhere            /* The WHERE clause */
ds@1952: ){
ds@1952:   TriggerStep *pTriggerStep = sqlite3DbMallocZero(db, sizeof(TriggerStep));
ds@1952:   if( pTriggerStep==0 ){
ds@1952:     sqlite3ExprDelete(pWhere);
ds@1952:     return 0;
ds@1952:   }
ds@1952: 
ds@1952:   pTriggerStep->op = TK_DELETE;
ds@1952:   pTriggerStep->target  = *pTableName;
ds@1952:   pTriggerStep->pWhere = pWhere;
ds@1952:   pTriggerStep->orconf = OE_Default;
ds@1952:   sqlitePersistTriggerStep(db, pTriggerStep);
ds@1952: 
ds@1952:   return pTriggerStep;
ds@1952: }
ds@1952: 
ds@1952: /* 
ds@1952: ** Recursively delete a Trigger structure
ds@1952: */
ds@1952: void sqlite3DeleteTrigger(Trigger *pTrigger){
ds@1952:   if( pTrigger==0 ) return;
ds@1952:   sqlite3DeleteTriggerStep(pTrigger->step_list);
ds@1952:   sqlite3_free(pTrigger->name);
ds@1952:   sqlite3_free(pTrigger->table);
ds@1952:   sqlite3ExprDelete(pTrigger->pWhen);
ds@1952:   sqlite3IdListDelete(pTrigger->pColumns);
ds@1952:   if( pTrigger->nameToken.dyn ) sqlite3_free((char*)pTrigger->nameToken.z);
ds@1952:   sqlite3_free(pTrigger);
ds@1952: }
ds@1952: 
ds@1952: /*
ds@1952: ** This function is called to drop a trigger from the database schema. 
ds@1952: **
ds@1952: ** This may be called directly from the parser and therefore identifies
ds@1952: ** the trigger by name.  The sqlite3DropTriggerPtr() routine does the
ds@1952: ** same job as this routine except it takes a pointer to the trigger
ds@1952: ** instead of the trigger name.
ds@1952: **/
ds@1952: void sqlite3DropTrigger(Parse *pParse, SrcList *pName, int noErr){
ds@1952:   Trigger *pTrigger = 0;
ds@1952:   int i;
ds@1952:   const char *zDb;
ds@1952:   const char *zName;
ds@1952:   int nName;
ds@1952:   sqlite3 *db = pParse->db;
ds@1952: 
ds@1952:   if( db->mallocFailed ) goto drop_trigger_cleanup;
ds@1952:   if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
ds@1952:     goto drop_trigger_cleanup;
ds@1952:   }
ds@1952: 
ds@1952:   assert( pName->nSrc==1 );
ds@1952:   zDb = pName->a[0].zDatabase;
ds@1952:   zName = pName->a[0].zName;
ds@1952:   nName = strlen(zName);
ds@1952:   for(i=OMIT_TEMPDB; i<db->nDb; i++){
ds@1952:     int j = (i<2) ? i^1 : i;  /* Search TEMP before MAIN */
ds@1952:     if( zDb && sqlite3StrICmp(db->aDb[j].zName, zDb) ) continue;
ds@1952:     pTrigger = sqlite3HashFind(&(db->aDb[j].pSchema->trigHash), zName, nName);
ds@1952:     if( pTrigger ) break;
ds@1952:   }
ds@1952:   if( !pTrigger ){
ds@1952:     if( !noErr ){
ds@1952:       sqlite3ErrorMsg(pParse, "no such trigger: %S", pName, 0);
ds@1952:     }
ds@1952:     goto drop_trigger_cleanup;
ds@1952:   }
ds@1952:   sqlite3DropTriggerPtr(pParse, pTrigger);
ds@1952: 
ds@1952: drop_trigger_cleanup:
ds@1952:   sqlite3SrcListDelete(pName);
ds@1952: }
ds@1952: 
ds@1952: /*
ds@1952: ** Return a pointer to the Table structure for the table that a trigger
ds@1952: ** is set on.
ds@1952: */
ds@1952: static Table *tableOfTrigger(Trigger *pTrigger){
ds@1952:   int n = strlen(pTrigger->table) + 1;
ds@1952:   return sqlite3HashFind(&pTrigger->pTabSchema->tblHash, pTrigger->table, n);
ds@1952: }
ds@1952: 
ds@1952: 
ds@1952: /*
ds@1952: ** Drop a trigger given a pointer to that trigger. 
ds@1952: */
ds@1952: void sqlite3DropTriggerPtr(Parse *pParse, Trigger *pTrigger){
ds@1952:   Table   *pTable;
ds@1952:   Vdbe *v;
ds@1952:   sqlite3 *db = pParse->db;
ds@1952:   int iDb;
ds@1952: 
ds@1952:   iDb = sqlite3SchemaToIndex(pParse->db, pTrigger->pSchema);
ds@1952:   assert( iDb>=0 && iDb<db->nDb );
ds@1952:   pTable = tableOfTrigger(pTrigger);
ds@1952:   assert( pTable );
ds@1952:   assert( pTable->pSchema==pTrigger->pSchema || iDb==1 );
ds@1952: #ifndef SQLITE_OMIT_AUTHORIZATION
ds@1952:   {
ds@1952:     int code = SQLITE_DROP_TRIGGER;
ds@1952:     const char *zDb = db->aDb[iDb].zName;
ds@1952:     const char *zTab = SCHEMA_TABLE(iDb);
ds@1952:     if( iDb==1 ) code = SQLITE_DROP_TEMP_TRIGGER;
ds@1952:     if( sqlite3AuthCheck(pParse, code, pTrigger->name, pTable->zName, zDb) ||
ds@1952:       sqlite3AuthCheck(pParse, SQLITE_DELETE, zTab, 0, zDb) ){
ds@1952:       return;
ds@1952:     }
ds@1952:   }
ds@1952: #endif
ds@1952: 
ds@1952:   /* Generate code to destroy the database record of the trigger.
ds@1952:   */
ds@1952:   assert( pTable!=0 );
ds@1952:   if( (v = sqlite3GetVdbe(pParse))!=0 ){
ds@1952:     int base;
ds@1952:     static const VdbeOpList dropTrigger[] = {
ds@1952:       { OP_Rewind,     0, ADDR(9),  0},
ds@1952:       { OP_String8,    0, 0,        0}, /* 1 */
ds@1952:       { OP_Column,     0, 1,        0},
ds@1952:       { OP_Ne,         0, ADDR(8),  0},
ds@1952:       { OP_String8,    0, 0,        "trigger"},
ds@1952:       { OP_Column,     0, 0,        0},
ds@1952:       { OP_Ne,         0, ADDR(8),  0},
ds@1952:       { OP_Delete,     0, 0,        0},
ds@1952:       { OP_Next,       0, ADDR(1),  0}, /* 8 */
ds@1952:     };
ds@1952: 
ds@1952:     sqlite3BeginWriteOperation(pParse, 0, iDb);
ds@1952:     sqlite3OpenMasterTable(pParse, iDb);
ds@1952:     base = sqlite3VdbeAddOpList(v,  ArraySize(dropTrigger), dropTrigger);
ds@1952:     sqlite3VdbeChangeP3(v, base+1, pTrigger->name, 0);
ds@1952:     sqlite3ChangeCookie(db, v, iDb);
ds@1952:     sqlite3VdbeAddOp(v, OP_Close, 0, 0);
ds@1952:     sqlite3VdbeOp3(v, OP_DropTrigger, iDb, 0, pTrigger->name, 0);
ds@1952:   }
ds@1952: }
ds@1952: 
ds@1952: /*
ds@1952: ** Remove a trigger from the hash tables of the sqlite* pointer.
ds@1952: */
ds@1952: void sqlite3UnlinkAndDeleteTrigger(sqlite3 *db, int iDb, const char *zName){
ds@1952:   Trigger *pTrigger;
ds@1952:   int nName = strlen(zName);
ds@1952:   pTrigger = sqlite3HashInsert(&(db->aDb[iDb].pSchema->trigHash),
ds@1952:                                zName, nName, 0);
ds@1952:   if( pTrigger ){
ds@1952:     Table *pTable = tableOfTrigger(pTrigger);
ds@1952:     assert( pTable!=0 );
ds@1952:     if( pTable->pTrigger == pTrigger ){
ds@1952:       pTable->pTrigger = pTrigger->pNext;
ds@1952:     }else{
ds@1952:       Trigger *cc = pTable->pTrigger;
ds@1952:       while( cc ){ 
ds@1952:         if( cc->pNext == pTrigger ){
ds@1952:           cc->pNext = cc->pNext->pNext;
ds@1952:           break;
ds@1952:         }
ds@1952:         cc = cc->pNext;
ds@1952:       }
ds@1952:       assert(cc);
ds@1952:     }
ds@1952:     sqlite3DeleteTrigger(pTrigger);
ds@1952:     db->flags |= SQLITE_InternChanges;
ds@1952:   }
ds@1952: }
ds@1952: 
ds@1952: /*
ds@1952: ** pEList is the SET clause of an UPDATE statement.  Each entry
ds@1952: ** in pEList is of the format <id>=<expr>.  If any of the entries
ds@1952: ** in pEList have an <id> which matches an identifier in pIdList,
ds@1952: ** then return TRUE.  If pIdList==NULL, then it is considered a
ds@1952: ** wildcard that matches anything.  Likewise if pEList==NULL then
ds@1952: ** it matches anything so always return true.  Return false only
ds@1952: ** if there is no match.
ds@1952: */
ds@1952: static int checkColumnOverLap(IdList *pIdList, ExprList *pEList){
ds@1952:   int e;
ds@1952:   if( !pIdList || !pEList ) return 1;
ds@1952:   for(e=0; e<pEList->nExpr; e++){
ds@1952:     if( sqlite3IdListIndex(pIdList, pEList->a[e].zName)>=0 ) return 1;
ds@1952:   }
ds@1952:   return 0; 
ds@1952: }
ds@1952: 
ds@1952: /*
ds@1952: ** Return a bit vector to indicate what kind of triggers exist for operation
ds@1952: ** "op" on table pTab.  If pChanges is not NULL then it is a list of columns
ds@1952: ** that are being updated.  Triggers only match if the ON clause of the
ds@1952: ** trigger definition overlaps the set of columns being updated.
ds@1952: **
ds@1952: ** The returned bit vector is some combination of TRIGGER_BEFORE and
ds@1952: ** TRIGGER_AFTER.
ds@1952: */
ds@1952: int sqlite3TriggersExist(
ds@1952:   Parse *pParse,          /* Used to check for recursive triggers */
ds@1952:   Table *pTab,            /* The table the contains the triggers */
ds@1952:   int op,                 /* one of TK_DELETE, TK_INSERT, TK_UPDATE */
ds@1952:   ExprList *pChanges      /* Columns that change in an UPDATE statement */
ds@1952: ){
ds@1952:   Trigger *pTrigger;
ds@1952:   int mask = 0;
ds@1952: 
ds@1952:   pTrigger = IsVirtual(pTab) ? 0 : pTab->pTrigger;
ds@1952:   while( pTrigger ){
ds@1952:     if( pTrigger->op==op && checkColumnOverLap(pTrigger->pColumns, pChanges) ){
ds@1952:       mask |= pTrigger->tr_tm;
ds@1952:     }
ds@1952:     pTrigger = pTrigger->pNext;
ds@1952:   }
ds@1952:   return mask;
ds@1952: }
ds@1952: 
ds@1952: /*
ds@1952: ** Convert the pStep->target token into a SrcList and return a pointer
ds@1952: ** to that SrcList.
ds@1952: **
ds@1952: ** This routine adds a specific database name, if needed, to the target when
ds@1952: ** forming the SrcList.  This prevents a trigger in one database from
ds@1952: ** referring to a target in another database.  An exception is when the
ds@1952: ** trigger is in TEMP in which case it can refer to any other database it
ds@1952: ** wants.
ds@1952: */
ds@1952: static SrcList *targetSrcList(
ds@1952:   Parse *pParse,       /* The parsing context */
ds@1952:   TriggerStep *pStep   /* The trigger containing the target token */
ds@1952: ){
ds@1952:   Token sDb;           /* Dummy database name token */
ds@1952:   int iDb;             /* Index of the database to use */
ds@1952:   SrcList *pSrc;       /* SrcList to be returned */
ds@1952: 
ds@1952:   iDb = sqlite3SchemaToIndex(pParse->db, pStep->pTrig->pSchema);
ds@1952:   if( iDb==0 || iDb>=2 ){
ds@1952:     assert( iDb<pParse->db->nDb );
ds@1952:     sDb.z = (u8*)pParse->db->aDb[iDb].zName;
ds@1952:     sDb.n = strlen((char*)sDb.z);
ds@1952:     pSrc = sqlite3SrcListAppend(pParse->db, 0, &sDb, &pStep->target);
ds@1952:   } else {
ds@1952:     pSrc = sqlite3SrcListAppend(pParse->db, 0, &pStep->target, 0);
ds@1952:   }
ds@1952:   return pSrc;
ds@1952: }
ds@1952: 
ds@1952: /*
ds@1952: ** Generate VDBE code for zero or more statements inside the body of a
ds@1952: ** trigger.  
ds@1952: */
ds@1952: static int codeTriggerProgram(
ds@1952:   Parse *pParse,            /* The parser context */
ds@1952:   TriggerStep *pStepList,   /* List of statements inside the trigger body */
ds@1952:   int orconfin              /* Conflict algorithm. (OE_Abort, etc) */  
ds@1952: ){
ds@1952:   TriggerStep * pTriggerStep = pStepList;
ds@1952:   int orconf;
ds@1952:   Vdbe *v = pParse->pVdbe;
ds@1952:   sqlite3 *db = pParse->db;
ds@1952: 
ds@1952:   assert( pTriggerStep!=0 );
ds@1952:   assert( v!=0 );
ds@1952:   sqlite3VdbeAddOp(v, OP_ContextPush, 0, 0);
ds@1952:   VdbeComment((v, "# begin trigger %s", pStepList->pTrig->name));
ds@1952:   while( pTriggerStep ){
ds@1952:     orconf = (orconfin == OE_Default)?pTriggerStep->orconf:orconfin;
ds@1952:     pParse->trigStack->orconf = orconf;
ds@1952:     switch( pTriggerStep->op ){
ds@1952:       case TK_SELECT: {
ds@1952:         Select *ss = sqlite3SelectDup(db, pTriggerStep->pSelect);
ds@1952:         if( ss ){
ds@1952:           sqlite3SelectResolve(pParse, ss, 0);
ds@1952:           sqlite3Select(pParse, ss, SRT_Discard, 0, 0, 0, 0, 0);
ds@1952:           sqlite3SelectDelete(ss);
ds@1952:         }
ds@1952:         break;
ds@1952:       }
ds@1952:       case TK_UPDATE: {
ds@1952:         SrcList *pSrc;
ds@1952:         pSrc = targetSrcList(pParse, pTriggerStep);
ds@1952:         sqlite3VdbeAddOp(v, OP_ResetCount, 0, 0);
ds@1952:         sqlite3Update(pParse, pSrc,
ds@1952:                 sqlite3ExprListDup(db, pTriggerStep->pExprList), 
ds@1952:                 sqlite3ExprDup(db, pTriggerStep->pWhere), orconf);
ds@1952:         sqlite3VdbeAddOp(v, OP_ResetCount, 1, 0);
ds@1952:         break;
ds@1952:       }
ds@1952:       case TK_INSERT: {
ds@1952:         SrcList *pSrc;
ds@1952:         pSrc = targetSrcList(pParse, pTriggerStep);
ds@1952:         sqlite3VdbeAddOp(v, OP_ResetCount, 0, 0);
ds@1952:         sqlite3Insert(pParse, pSrc,
ds@1952:           sqlite3ExprListDup(db, pTriggerStep->pExprList), 
ds@1952:           sqlite3SelectDup(db, pTriggerStep->pSelect), 
ds@1952:           sqlite3IdListDup(db, pTriggerStep->pIdList), orconf);
ds@1952:         sqlite3VdbeAddOp(v, OP_ResetCount, 1, 0);
ds@1952:         break;
ds@1952:       }
ds@1952:       case TK_DELETE: {
ds@1952:         SrcList *pSrc;
ds@1952:         sqlite3VdbeAddOp(v, OP_ResetCount, 0, 0);
ds@1952:         pSrc = targetSrcList(pParse, pTriggerStep);
ds@1952:         sqlite3DeleteFrom(pParse, pSrc, 
ds@1952:                           sqlite3ExprDup(db, pTriggerStep->pWhere));
ds@1952:         sqlite3VdbeAddOp(v, OP_ResetCount, 1, 0);
ds@1952:         break;
ds@1952:       }
ds@1952:       default:
ds@1952:         assert(0);
ds@1952:     } 
ds@1952:     pTriggerStep = pTriggerStep->pNext;
ds@1952:   }
ds@1952:   sqlite3VdbeAddOp(v, OP_ContextPop, 0, 0);
ds@1952:   VdbeComment((v, "# end trigger %s", pStepList->pTrig->name));
ds@1952: 
ds@1952:   return 0;
ds@1952: }
ds@1952: 
ds@1952: /*
ds@1952: ** This is called to code FOR EACH ROW triggers.
ds@1952: **
ds@1952: ** When the code that this function generates is executed, the following 
ds@1952: ** must be true:
ds@1952: **
ds@1952: ** 1. No cursors may be open in the main database.  (But newIdx and oldIdx
ds@1952: **    can be indices of cursors in temporary tables.  See below.)
ds@1952: **
ds@1952: ** 2. If the triggers being coded are ON INSERT or ON UPDATE triggers, then
ds@1952: **    a temporary vdbe cursor (index newIdx) must be open and pointing at
ds@1952: **    a row containing values to be substituted for new.* expressions in the
ds@1952: **    trigger program(s).
ds@1952: **
ds@1952: ** 3. If the triggers being coded are ON DELETE or ON UPDATE triggers, then
ds@1952: **    a temporary vdbe cursor (index oldIdx) must be open and pointing at
ds@1952: **    a row containing values to be substituted for old.* expressions in the
ds@1952: **    trigger program(s).
ds@1952: **
ds@1952: */
ds@1952: int sqlite3CodeRowTrigger(
ds@1952:   Parse *pParse,       /* Parse context */
ds@1952:   int op,              /* One of TK_UPDATE, TK_INSERT, TK_DELETE */
ds@1952:   ExprList *pChanges,  /* Changes list for any UPDATE OF triggers */
ds@1952:   int tr_tm,           /* One of TRIGGER_BEFORE, TRIGGER_AFTER */
ds@1952:   Table *pTab,         /* The table to code triggers from */
ds@1952:   int newIdx,          /* The indice of the "new" row to access */
ds@1952:   int oldIdx,          /* The indice of the "old" row to access */
ds@1952:   int orconf,          /* ON CONFLICT policy */
ds@1952:   int ignoreJump       /* Instruction to jump to for RAISE(IGNORE) */
ds@1952: ){
ds@1952:   Trigger *p;
ds@1952:   TriggerStack trigStackEntry;
ds@1952: 
ds@1952:   assert(op == TK_UPDATE || op == TK_INSERT || op == TK_DELETE);
ds@1952:   assert(tr_tm == TRIGGER_BEFORE || tr_tm == TRIGGER_AFTER );
ds@1952: 
ds@1952:   assert(newIdx != -1 || oldIdx != -1);
ds@1952: 
ds@1952:   for(p=pTab->pTrigger; p; p=p->pNext){
ds@1952:     int fire_this = 0;
ds@1952: 
ds@1952:     /* Determine whether we should code this trigger */
ds@1952:     if( 
ds@1952:       p->op==op && 
ds@1952:       p->tr_tm==tr_tm && 
ds@1952:       (p->pSchema==p->pTabSchema || p->pSchema==pParse->db->aDb[1].pSchema) &&
ds@1952:       (op!=TK_UPDATE||!p->pColumns||checkColumnOverLap(p->pColumns,pChanges))
ds@1952:     ){
ds@1952:       TriggerStack *pS;      /* Pointer to trigger-stack entry */
ds@1952:       for(pS=pParse->trigStack; pS && p!=pS->pTrigger; pS=pS->pNext){}
ds@1952:       if( !pS ){
ds@1952:         fire_this = 1;
ds@1952:       }
ds@1952: #if 0    /* Give no warning for recursive triggers.  Just do not do them */
ds@1952:       else{
ds@1952:         sqlite3ErrorMsg(pParse, "recursive triggers not supported (%s)",
ds@1952:             p->name);
ds@1952:         return SQLITE_ERROR;
ds@1952:       }
ds@1952: #endif
ds@1952:     }
ds@1952:  
ds@1952:     if( fire_this ){
ds@1952:       int endTrigger;
ds@1952:       Expr * whenExpr;
ds@1952:       AuthContext sContext;
ds@1952:       NameContext sNC;
ds@1952: 
ds@1952:       memset(&sNC, 0, sizeof(sNC));
ds@1952:       sNC.pParse = pParse;
ds@1952: 
ds@1952:       /* Push an entry on to the trigger stack */
ds@1952:       trigStackEntry.pTrigger = p;
ds@1952:       trigStackEntry.newIdx = newIdx;
ds@1952:       trigStackEntry.oldIdx = oldIdx;
ds@1952:       trigStackEntry.pTab = pTab;
ds@1952:       trigStackEntry.pNext = pParse->trigStack;
ds@1952:       trigStackEntry.ignoreJump = ignoreJump;
ds@1952:       pParse->trigStack = &trigStackEntry;
ds@1952:       sqlite3AuthContextPush(pParse, &sContext, p->name);
ds@1952: 
ds@1952:       /* code the WHEN clause */
ds@1952:       endTrigger = sqlite3VdbeMakeLabel(pParse->pVdbe);
ds@1952:       whenExpr = sqlite3ExprDup(pParse->db, p->pWhen);
ds@1952:       if( sqlite3ExprResolveNames(&sNC, whenExpr) ){
ds@1952:         pParse->trigStack = trigStackEntry.pNext;
ds@1952:         sqlite3ExprDelete(whenExpr);
ds@1952:         return 1;
ds@1952:       }
ds@1952:       sqlite3ExprIfFalse(pParse, whenExpr, endTrigger, 1);
ds@1952:       sqlite3ExprDelete(whenExpr);
ds@1952: 
ds@1952:       codeTriggerProgram(pParse, p->step_list, orconf); 
ds@1952: 
ds@1952:       /* Pop the entry off the trigger stack */
ds@1952:       pParse->trigStack = trigStackEntry.pNext;
ds@1952:       sqlite3AuthContextPop(&sContext);
ds@1952: 
ds@1952:       sqlite3VdbeResolveLabel(pParse->pVdbe, endTrigger);
ds@1952:     }
ds@1952:   }
ds@1952:   return 0;
ds@1952: }
ds@1952: #endif /* !defined(SQLITE_OMIT_TRIGGER) */