1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/os/persistentdata/persistentstorage/sql/SQLite/trigger.c Fri Jun 15 03:10:57 2012 +0200
1.3 @@ -0,0 +1,853 @@
1.4 +/*
1.5 +**
1.6 +** The author disclaims copyright to this source code. In place of
1.7 +** a legal notice, here is a blessing:
1.8 +**
1.9 +** May you do good and not evil.
1.10 +** May you find forgiveness for yourself and forgive others.
1.11 +** May you share freely, never taking more than you give.
1.12 +**
1.13 +*************************************************************************
1.14 +**
1.15 +**
1.16 +** $Id: trigger.c,v 1.128 2008/07/28 19:34:54 drh Exp $
1.17 +*/
1.18 +#include "sqliteInt.h"
1.19 +
1.20 +#ifndef SQLITE_OMIT_TRIGGER
1.21 +/*
1.22 +** Delete a linked list of TriggerStep structures.
1.23 +*/
1.24 +void sqlite3DeleteTriggerStep(sqlite3 *db, TriggerStep *pTriggerStep){
1.25 + while( pTriggerStep ){
1.26 + TriggerStep * pTmp = pTriggerStep;
1.27 + pTriggerStep = pTriggerStep->pNext;
1.28 +
1.29 + if( pTmp->target.dyn ) sqlite3DbFree(db, (char*)pTmp->target.z);
1.30 + sqlite3ExprDelete(db, pTmp->pWhere);
1.31 + sqlite3ExprListDelete(db, pTmp->pExprList);
1.32 + sqlite3SelectDelete(db, pTmp->pSelect);
1.33 + sqlite3IdListDelete(db, pTmp->pIdList);
1.34 +
1.35 + sqlite3DbFree(db, pTmp);
1.36 + }
1.37 +}
1.38 +
1.39 +/*
1.40 +** This is called by the parser when it sees a CREATE TRIGGER statement
1.41 +** up to the point of the BEGIN before the trigger actions. A Trigger
1.42 +** structure is generated based on the information available and stored
1.43 +** in pParse->pNewTrigger. After the trigger actions have been parsed, the
1.44 +** sqlite3FinishTrigger() function is called to complete the trigger
1.45 +** construction process.
1.46 +*/
1.47 +void sqlite3BeginTrigger(
1.48 + Parse *pParse, /* The parse context of the CREATE TRIGGER statement */
1.49 + Token *pName1, /* The name of the trigger */
1.50 + Token *pName2, /* The name of the trigger */
1.51 + int tr_tm, /* One of TK_BEFORE, TK_AFTER, TK_INSTEAD */
1.52 + int op, /* One of TK_INSERT, TK_UPDATE, TK_DELETE */
1.53 + IdList *pColumns, /* column list if this is an UPDATE OF trigger */
1.54 + SrcList *pTableName,/* The name of the table/view the trigger applies to */
1.55 + Expr *pWhen, /* WHEN clause */
1.56 + int isTemp, /* True if the TEMPORARY keyword is present */
1.57 + int noErr /* Suppress errors if the trigger already exists */
1.58 +){
1.59 + Trigger *pTrigger = 0;
1.60 + Table *pTab;
1.61 + char *zName = 0; /* Name of the trigger */
1.62 + sqlite3 *db = pParse->db;
1.63 + int iDb; /* The database to store the trigger in */
1.64 + Token *pName; /* The unqualified db name */
1.65 + DbFixer sFix;
1.66 + int iTabDb;
1.67 +
1.68 + assert( pName1!=0 ); /* pName1->z might be NULL, but not pName1 itself */
1.69 + assert( pName2!=0 );
1.70 + if( isTemp ){
1.71 + /* If TEMP was specified, then the trigger name may not be qualified. */
1.72 + if( pName2->n>0 ){
1.73 + sqlite3ErrorMsg(pParse, "temporary trigger may not have qualified name");
1.74 + goto trigger_cleanup;
1.75 + }
1.76 + iDb = 1;
1.77 + pName = pName1;
1.78 + }else{
1.79 + /* Figure out the db that the the trigger will be created in */
1.80 + iDb = sqlite3TwoPartName(pParse, pName1, pName2, &pName);
1.81 + if( iDb<0 ){
1.82 + goto trigger_cleanup;
1.83 + }
1.84 + }
1.85 +
1.86 + /* If the trigger name was unqualified, and the table is a temp table,
1.87 + ** then set iDb to 1 to create the trigger in the temporary database.
1.88 + ** If sqlite3SrcListLookup() returns 0, indicating the table does not
1.89 + ** exist, the error is caught by the block below.
1.90 + */
1.91 + if( !pTableName || db->mallocFailed ){
1.92 + goto trigger_cleanup;
1.93 + }
1.94 + pTab = sqlite3SrcListLookup(pParse, pTableName);
1.95 + if( pName2->n==0 && pTab && pTab->pSchema==db->aDb[1].pSchema ){
1.96 + iDb = 1;
1.97 + }
1.98 +
1.99 + /* Ensure the table name matches database name and that the table exists */
1.100 + if( db->mallocFailed ) goto trigger_cleanup;
1.101 + assert( pTableName->nSrc==1 );
1.102 + if( sqlite3FixInit(&sFix, pParse, iDb, "trigger", pName) &&
1.103 + sqlite3FixSrcList(&sFix, pTableName) ){
1.104 + goto trigger_cleanup;
1.105 + }
1.106 + pTab = sqlite3SrcListLookup(pParse, pTableName);
1.107 + if( !pTab ){
1.108 + /* The table does not exist. */
1.109 + goto trigger_cleanup;
1.110 + }
1.111 + if( IsVirtual(pTab) ){
1.112 + sqlite3ErrorMsg(pParse, "cannot create triggers on virtual tables");
1.113 + goto trigger_cleanup;
1.114 + }
1.115 +
1.116 + /* Check that the trigger name is not reserved and that no trigger of the
1.117 + ** specified name exists */
1.118 + zName = sqlite3NameFromToken(db, pName);
1.119 + if( !zName || SQLITE_OK!=sqlite3CheckObjectName(pParse, zName) ){
1.120 + goto trigger_cleanup;
1.121 + }
1.122 + if( sqlite3HashFind(&(db->aDb[iDb].pSchema->trigHash), zName,strlen(zName)) ){
1.123 + if( !noErr ){
1.124 + sqlite3ErrorMsg(pParse, "trigger %T already exists", pName);
1.125 + }
1.126 + goto trigger_cleanup;
1.127 + }
1.128 +
1.129 + /* Do not create a trigger on a system table */
1.130 + if( sqlite3StrNICmp(pTab->zName, "sqlite_", 7)==0 ){
1.131 + sqlite3ErrorMsg(pParse, "cannot create trigger on system table");
1.132 + pParse->nErr++;
1.133 + goto trigger_cleanup;
1.134 + }
1.135 +
1.136 + /* INSTEAD of triggers are only for views and views only support INSTEAD
1.137 + ** of triggers.
1.138 + */
1.139 + if( pTab->pSelect && tr_tm!=TK_INSTEAD ){
1.140 + sqlite3ErrorMsg(pParse, "cannot create %s trigger on view: %S",
1.141 + (tr_tm == TK_BEFORE)?"BEFORE":"AFTER", pTableName, 0);
1.142 + goto trigger_cleanup;
1.143 + }
1.144 + if( !pTab->pSelect && tr_tm==TK_INSTEAD ){
1.145 + sqlite3ErrorMsg(pParse, "cannot create INSTEAD OF"
1.146 + " trigger on table: %S", pTableName, 0);
1.147 + goto trigger_cleanup;
1.148 + }
1.149 + iTabDb = sqlite3SchemaToIndex(db, pTab->pSchema);
1.150 +
1.151 +#ifndef SQLITE_OMIT_AUTHORIZATION
1.152 + {
1.153 + int code = SQLITE_CREATE_TRIGGER;
1.154 + const char *zDb = db->aDb[iTabDb].zName;
1.155 + const char *zDbTrig = isTemp ? db->aDb[1].zName : zDb;
1.156 + if( iTabDb==1 || isTemp ) code = SQLITE_CREATE_TEMP_TRIGGER;
1.157 + if( sqlite3AuthCheck(pParse, code, zName, pTab->zName, zDbTrig) ){
1.158 + goto trigger_cleanup;
1.159 + }
1.160 + if( sqlite3AuthCheck(pParse, SQLITE_INSERT, SCHEMA_TABLE(iTabDb),0,zDb)){
1.161 + goto trigger_cleanup;
1.162 + }
1.163 + }
1.164 +#endif
1.165 +
1.166 + /* INSTEAD OF triggers can only appear on views and BEFORE triggers
1.167 + ** cannot appear on views. So we might as well translate every
1.168 + ** INSTEAD OF trigger into a BEFORE trigger. It simplifies code
1.169 + ** elsewhere.
1.170 + */
1.171 + if (tr_tm == TK_INSTEAD){
1.172 + tr_tm = TK_BEFORE;
1.173 + }
1.174 +
1.175 + /* Build the Trigger object */
1.176 + pTrigger = (Trigger*)sqlite3DbMallocZero(db, sizeof(Trigger));
1.177 + if( pTrigger==0 ) goto trigger_cleanup;
1.178 + pTrigger->name = zName;
1.179 + zName = 0;
1.180 + pTrigger->table = sqlite3DbStrDup(db, pTableName->a[0].zName);
1.181 + pTrigger->pSchema = db->aDb[iDb].pSchema;
1.182 + pTrigger->pTabSchema = pTab->pSchema;
1.183 + pTrigger->op = op;
1.184 + pTrigger->tr_tm = tr_tm==TK_BEFORE ? TRIGGER_BEFORE : TRIGGER_AFTER;
1.185 + pTrigger->pWhen = sqlite3ExprDup(db, pWhen);
1.186 + pTrigger->pColumns = sqlite3IdListDup(db, pColumns);
1.187 + sqlite3TokenCopy(db, &pTrigger->nameToken,pName);
1.188 + assert( pParse->pNewTrigger==0 );
1.189 + pParse->pNewTrigger = pTrigger;
1.190 +
1.191 +trigger_cleanup:
1.192 + sqlite3DbFree(db, zName);
1.193 + sqlite3SrcListDelete(db, pTableName);
1.194 + sqlite3IdListDelete(db, pColumns);
1.195 + sqlite3ExprDelete(db, pWhen);
1.196 + if( !pParse->pNewTrigger ){
1.197 + sqlite3DeleteTrigger(db, pTrigger);
1.198 + }else{
1.199 + assert( pParse->pNewTrigger==pTrigger );
1.200 + }
1.201 +}
1.202 +
1.203 +/*
1.204 +** This routine is called after all of the trigger actions have been parsed
1.205 +** in order to complete the process of building the trigger.
1.206 +*/
1.207 +void sqlite3FinishTrigger(
1.208 + Parse *pParse, /* Parser context */
1.209 + TriggerStep *pStepList, /* The triggered program */
1.210 + Token *pAll /* Token that describes the complete CREATE TRIGGER */
1.211 +){
1.212 + Trigger *pTrig = 0; /* The trigger whose construction is finishing up */
1.213 + sqlite3 *db = pParse->db; /* The database */
1.214 + DbFixer sFix;
1.215 + int iDb; /* Database containing the trigger */
1.216 +
1.217 + pTrig = pParse->pNewTrigger;
1.218 + pParse->pNewTrigger = 0;
1.219 + if( pParse->nErr || !pTrig ) goto triggerfinish_cleanup;
1.220 + iDb = sqlite3SchemaToIndex(pParse->db, pTrig->pSchema);
1.221 + pTrig->step_list = pStepList;
1.222 + while( pStepList ){
1.223 + pStepList->pTrig = pTrig;
1.224 + pStepList = pStepList->pNext;
1.225 + }
1.226 + if( sqlite3FixInit(&sFix, pParse, iDb, "trigger", &pTrig->nameToken)
1.227 + && sqlite3FixTriggerStep(&sFix, pTrig->step_list) ){
1.228 + goto triggerfinish_cleanup;
1.229 + }
1.230 +
1.231 + /* if we are not initializing, and this trigger is not on a TEMP table,
1.232 + ** build the sqlite_master entry
1.233 + */
1.234 + if( !db->init.busy ){
1.235 + Vdbe *v;
1.236 + char *z;
1.237 +
1.238 + /* Make an entry in the sqlite_master table */
1.239 + v = sqlite3GetVdbe(pParse);
1.240 + if( v==0 ) goto triggerfinish_cleanup;
1.241 + sqlite3BeginWriteOperation(pParse, 0, iDb);
1.242 + z = sqlite3DbStrNDup(db, (char*)pAll->z, pAll->n);
1.243 + sqlite3NestedParse(pParse,
1.244 + "INSERT INTO %Q.%s VALUES('trigger',%Q,%Q,0,'CREATE TRIGGER %q')",
1.245 + db->aDb[iDb].zName, SCHEMA_TABLE(iDb), pTrig->name,
1.246 + pTrig->table, z);
1.247 + sqlite3DbFree(db, z);
1.248 + sqlite3ChangeCookie(pParse, iDb);
1.249 + sqlite3VdbeAddOp4(v, OP_ParseSchema, iDb, 0, 0, sqlite3MPrintf(
1.250 + db, "type='trigger' AND name='%q'", pTrig->name), P4_DYNAMIC
1.251 + );
1.252 + }
1.253 +
1.254 + if( db->init.busy ){
1.255 + int n;
1.256 + Table *pTab;
1.257 + Trigger *pDel;
1.258 + pDel = sqlite3HashInsert(&db->aDb[iDb].pSchema->trigHash,
1.259 + pTrig->name, strlen(pTrig->name), pTrig);
1.260 + if( pDel ){
1.261 + assert( pDel==pTrig );
1.262 + db->mallocFailed = 1;
1.263 + goto triggerfinish_cleanup;
1.264 + }
1.265 + n = strlen(pTrig->table) + 1;
1.266 + pTab = sqlite3HashFind(&pTrig->pTabSchema->tblHash, pTrig->table, n);
1.267 + assert( pTab!=0 );
1.268 + pTrig->pNext = pTab->pTrigger;
1.269 + pTab->pTrigger = pTrig;
1.270 + pTrig = 0;
1.271 + }
1.272 +
1.273 +triggerfinish_cleanup:
1.274 + sqlite3DeleteTrigger(db, pTrig);
1.275 + assert( !pParse->pNewTrigger );
1.276 + sqlite3DeleteTriggerStep(db, pStepList);
1.277 +}
1.278 +
1.279 +/*
1.280 +** Make a copy of all components of the given trigger step. This has
1.281 +** the effect of copying all Expr.token.z values into memory obtained
1.282 +** from sqlite3_malloc(). As initially created, the Expr.token.z values
1.283 +** all point to the input string that was fed to the parser. But that
1.284 +** string is ephemeral - it will go away as soon as the sqlite3_exec()
1.285 +** call that started the parser exits. This routine makes a persistent
1.286 +** copy of all the Expr.token.z strings so that the TriggerStep structure
1.287 +** will be valid even after the sqlite3_exec() call returns.
1.288 +*/
1.289 +static void sqlitePersistTriggerStep(sqlite3 *db, TriggerStep *p){
1.290 + if( p->target.z ){
1.291 + p->target.z = (u8*)sqlite3DbStrNDup(db, (char*)p->target.z, p->target.n);
1.292 + p->target.dyn = 1;
1.293 + }
1.294 + if( p->pSelect ){
1.295 + Select *pNew = sqlite3SelectDup(db, p->pSelect);
1.296 + sqlite3SelectDelete(db, p->pSelect);
1.297 + p->pSelect = pNew;
1.298 + }
1.299 + if( p->pWhere ){
1.300 + Expr *pNew = sqlite3ExprDup(db, p->pWhere);
1.301 + sqlite3ExprDelete(db, p->pWhere);
1.302 + p->pWhere = pNew;
1.303 + }
1.304 + if( p->pExprList ){
1.305 + ExprList *pNew = sqlite3ExprListDup(db, p->pExprList);
1.306 + sqlite3ExprListDelete(db, p->pExprList);
1.307 + p->pExprList = pNew;
1.308 + }
1.309 + if( p->pIdList ){
1.310 + IdList *pNew = sqlite3IdListDup(db, p->pIdList);
1.311 + sqlite3IdListDelete(db, p->pIdList);
1.312 + p->pIdList = pNew;
1.313 + }
1.314 +}
1.315 +
1.316 +/*
1.317 +** Turn a SELECT statement (that the pSelect parameter points to) into
1.318 +** a trigger step. Return a pointer to a TriggerStep structure.
1.319 +**
1.320 +** The parser calls this routine when it finds a SELECT statement in
1.321 +** body of a TRIGGER.
1.322 +*/
1.323 +TriggerStep *sqlite3TriggerSelectStep(sqlite3 *db, Select *pSelect){
1.324 + TriggerStep *pTriggerStep = sqlite3DbMallocZero(db, sizeof(TriggerStep));
1.325 + if( pTriggerStep==0 ) {
1.326 + sqlite3SelectDelete(db, pSelect);
1.327 + return 0;
1.328 + }
1.329 +
1.330 + pTriggerStep->op = TK_SELECT;
1.331 + pTriggerStep->pSelect = pSelect;
1.332 + pTriggerStep->orconf = OE_Default;
1.333 + sqlitePersistTriggerStep(db, pTriggerStep);
1.334 +
1.335 + return pTriggerStep;
1.336 +}
1.337 +
1.338 +/*
1.339 +** Build a trigger step out of an INSERT statement. Return a pointer
1.340 +** to the new trigger step.
1.341 +**
1.342 +** The parser calls this routine when it sees an INSERT inside the
1.343 +** body of a trigger.
1.344 +*/
1.345 +TriggerStep *sqlite3TriggerInsertStep(
1.346 + sqlite3 *db, /* The database connection */
1.347 + Token *pTableName, /* Name of the table into which we insert */
1.348 + IdList *pColumn, /* List of columns in pTableName to insert into */
1.349 + ExprList *pEList, /* The VALUE clause: a list of values to be inserted */
1.350 + Select *pSelect, /* A SELECT statement that supplies values */
1.351 + int orconf /* The conflict algorithm (OE_Abort, OE_Replace, etc.) */
1.352 +){
1.353 + TriggerStep *pTriggerStep;
1.354 +
1.355 + assert(pEList == 0 || pSelect == 0);
1.356 + assert(pEList != 0 || pSelect != 0 || db->mallocFailed);
1.357 +
1.358 + pTriggerStep = sqlite3DbMallocZero(db, sizeof(TriggerStep));
1.359 + if( pTriggerStep ){
1.360 + pTriggerStep->op = TK_INSERT;
1.361 + pTriggerStep->pSelect = pSelect;
1.362 + pTriggerStep->target = *pTableName;
1.363 + pTriggerStep->pIdList = pColumn;
1.364 + pTriggerStep->pExprList = pEList;
1.365 + pTriggerStep->orconf = orconf;
1.366 + sqlitePersistTriggerStep(db, pTriggerStep);
1.367 + }else{
1.368 + sqlite3IdListDelete(db, pColumn);
1.369 + sqlite3ExprListDelete(db, pEList);
1.370 + sqlite3SelectDelete(db, pSelect);
1.371 + }
1.372 +
1.373 + return pTriggerStep;
1.374 +}
1.375 +
1.376 +/*
1.377 +** Construct a trigger step that implements an UPDATE statement and return
1.378 +** a pointer to that trigger step. The parser calls this routine when it
1.379 +** sees an UPDATE statement inside the body of a CREATE TRIGGER.
1.380 +*/
1.381 +TriggerStep *sqlite3TriggerUpdateStep(
1.382 + sqlite3 *db, /* The database connection */
1.383 + Token *pTableName, /* Name of the table to be updated */
1.384 + ExprList *pEList, /* The SET clause: list of column and new values */
1.385 + Expr *pWhere, /* The WHERE clause */
1.386 + int orconf /* The conflict algorithm. (OE_Abort, OE_Ignore, etc) */
1.387 +){
1.388 + TriggerStep *pTriggerStep = sqlite3DbMallocZero(db, sizeof(TriggerStep));
1.389 + if( pTriggerStep==0 ){
1.390 + sqlite3ExprListDelete(db, pEList);
1.391 + sqlite3ExprDelete(db, pWhere);
1.392 + return 0;
1.393 + }
1.394 +
1.395 + pTriggerStep->op = TK_UPDATE;
1.396 + pTriggerStep->target = *pTableName;
1.397 + pTriggerStep->pExprList = pEList;
1.398 + pTriggerStep->pWhere = pWhere;
1.399 + pTriggerStep->orconf = orconf;
1.400 + sqlitePersistTriggerStep(db, pTriggerStep);
1.401 +
1.402 + return pTriggerStep;
1.403 +}
1.404 +
1.405 +/*
1.406 +** Construct a trigger step that implements a DELETE statement and return
1.407 +** a pointer to that trigger step. The parser calls this routine when it
1.408 +** sees a DELETE statement inside the body of a CREATE TRIGGER.
1.409 +*/
1.410 +TriggerStep *sqlite3TriggerDeleteStep(
1.411 + sqlite3 *db, /* Database connection */
1.412 + Token *pTableName, /* The table from which rows are deleted */
1.413 + Expr *pWhere /* The WHERE clause */
1.414 +){
1.415 + TriggerStep *pTriggerStep = sqlite3DbMallocZero(db, sizeof(TriggerStep));
1.416 + if( pTriggerStep==0 ){
1.417 + sqlite3ExprDelete(db, pWhere);
1.418 + return 0;
1.419 + }
1.420 +
1.421 + pTriggerStep->op = TK_DELETE;
1.422 + pTriggerStep->target = *pTableName;
1.423 + pTriggerStep->pWhere = pWhere;
1.424 + pTriggerStep->orconf = OE_Default;
1.425 + sqlitePersistTriggerStep(db, pTriggerStep);
1.426 +
1.427 + return pTriggerStep;
1.428 +}
1.429 +
1.430 +/*
1.431 +** Recursively delete a Trigger structure
1.432 +*/
1.433 +void sqlite3DeleteTrigger(sqlite3 *db, Trigger *pTrigger){
1.434 + if( pTrigger==0 ) return;
1.435 + sqlite3DeleteTriggerStep(db, pTrigger->step_list);
1.436 + sqlite3DbFree(db, pTrigger->name);
1.437 + sqlite3DbFree(db, pTrigger->table);
1.438 + sqlite3ExprDelete(db, pTrigger->pWhen);
1.439 + sqlite3IdListDelete(db, pTrigger->pColumns);
1.440 + if( pTrigger->nameToken.dyn ) sqlite3DbFree(db, (char*)pTrigger->nameToken.z);
1.441 + sqlite3DbFree(db, pTrigger);
1.442 +}
1.443 +
1.444 +/*
1.445 +** This function is called to drop a trigger from the database schema.
1.446 +**
1.447 +** This may be called directly from the parser and therefore identifies
1.448 +** the trigger by name. The sqlite3DropTriggerPtr() routine does the
1.449 +** same job as this routine except it takes a pointer to the trigger
1.450 +** instead of the trigger name.
1.451 +**/
1.452 +void sqlite3DropTrigger(Parse *pParse, SrcList *pName, int noErr){
1.453 + Trigger *pTrigger = 0;
1.454 + int i;
1.455 + const char *zDb;
1.456 + const char *zName;
1.457 + int nName;
1.458 + sqlite3 *db = pParse->db;
1.459 +
1.460 + if( db->mallocFailed ) goto drop_trigger_cleanup;
1.461 + if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
1.462 + goto drop_trigger_cleanup;
1.463 + }
1.464 +
1.465 + assert( pName->nSrc==1 );
1.466 + zDb = pName->a[0].zDatabase;
1.467 + zName = pName->a[0].zName;
1.468 + nName = strlen(zName);
1.469 + for(i=OMIT_TEMPDB; i<db->nDb; i++){
1.470 + int j = (i<2) ? i^1 : i; /* Search TEMP before MAIN */
1.471 + if( zDb && sqlite3StrICmp(db->aDb[j].zName, zDb) ) continue;
1.472 + pTrigger = sqlite3HashFind(&(db->aDb[j].pSchema->trigHash), zName, nName);
1.473 + if( pTrigger ) break;
1.474 + }
1.475 + if( !pTrigger ){
1.476 + if( !noErr ){
1.477 + sqlite3ErrorMsg(pParse, "no such trigger: %S", pName, 0);
1.478 + }
1.479 + goto drop_trigger_cleanup;
1.480 + }
1.481 + sqlite3DropTriggerPtr(pParse, pTrigger);
1.482 +
1.483 +drop_trigger_cleanup:
1.484 + sqlite3SrcListDelete(db, pName);
1.485 +}
1.486 +
1.487 +/*
1.488 +** Return a pointer to the Table structure for the table that a trigger
1.489 +** is set on.
1.490 +*/
1.491 +static Table *tableOfTrigger(Trigger *pTrigger){
1.492 + int n = strlen(pTrigger->table) + 1;
1.493 + return sqlite3HashFind(&pTrigger->pTabSchema->tblHash, pTrigger->table, n);
1.494 +}
1.495 +
1.496 +
1.497 +/*
1.498 +** Drop a trigger given a pointer to that trigger.
1.499 +*/
1.500 +void sqlite3DropTriggerPtr(Parse *pParse, Trigger *pTrigger){
1.501 + Table *pTable;
1.502 + Vdbe *v;
1.503 + sqlite3 *db = pParse->db;
1.504 + int iDb;
1.505 +
1.506 + iDb = sqlite3SchemaToIndex(pParse->db, pTrigger->pSchema);
1.507 + assert( iDb>=0 && iDb<db->nDb );
1.508 + pTable = tableOfTrigger(pTrigger);
1.509 + assert( pTable );
1.510 + assert( pTable->pSchema==pTrigger->pSchema || iDb==1 );
1.511 +#ifndef SQLITE_OMIT_AUTHORIZATION
1.512 + {
1.513 + int code = SQLITE_DROP_TRIGGER;
1.514 + const char *zDb = db->aDb[iDb].zName;
1.515 + const char *zTab = SCHEMA_TABLE(iDb);
1.516 + if( iDb==1 ) code = SQLITE_DROP_TEMP_TRIGGER;
1.517 + if( sqlite3AuthCheck(pParse, code, pTrigger->name, pTable->zName, zDb) ||
1.518 + sqlite3AuthCheck(pParse, SQLITE_DELETE, zTab, 0, zDb) ){
1.519 + return;
1.520 + }
1.521 + }
1.522 +#endif
1.523 +
1.524 + /* Generate code to destroy the database record of the trigger.
1.525 + */
1.526 + assert( pTable!=0 );
1.527 + if( (v = sqlite3GetVdbe(pParse))!=0 ){
1.528 + int base;
1.529 + static const VdbeOpList dropTrigger[] = {
1.530 + { OP_Rewind, 0, ADDR(9), 0},
1.531 + { OP_String8, 0, 1, 0}, /* 1 */
1.532 + { OP_Column, 0, 1, 2},
1.533 + { OP_Ne, 2, ADDR(8), 1},
1.534 + { OP_String8, 0, 1, 0}, /* 4: "trigger" */
1.535 + { OP_Column, 0, 0, 2},
1.536 + { OP_Ne, 2, ADDR(8), 1},
1.537 + { OP_Delete, 0, 0, 0},
1.538 + { OP_Next, 0, ADDR(1), 0}, /* 8 */
1.539 + };
1.540 +
1.541 + sqlite3BeginWriteOperation(pParse, 0, iDb);
1.542 + sqlite3OpenMasterTable(pParse, iDb);
1.543 + base = sqlite3VdbeAddOpList(v, ArraySize(dropTrigger), dropTrigger);
1.544 + sqlite3VdbeChangeP4(v, base+1, pTrigger->name, 0);
1.545 + sqlite3VdbeChangeP4(v, base+4, "trigger", P4_STATIC);
1.546 + sqlite3ChangeCookie(pParse, iDb);
1.547 + sqlite3VdbeAddOp2(v, OP_Close, 0, 0);
1.548 + sqlite3VdbeAddOp4(v, OP_DropTrigger, iDb, 0, 0, pTrigger->name, 0);
1.549 + }
1.550 +}
1.551 +
1.552 +/*
1.553 +** Remove a trigger from the hash tables of the sqlite* pointer.
1.554 +*/
1.555 +void sqlite3UnlinkAndDeleteTrigger(sqlite3 *db, int iDb, const char *zName){
1.556 + Trigger *pTrigger;
1.557 + int nName = strlen(zName);
1.558 + pTrigger = sqlite3HashInsert(&(db->aDb[iDb].pSchema->trigHash),
1.559 + zName, nName, 0);
1.560 + if( pTrigger ){
1.561 + Table *pTable = tableOfTrigger(pTrigger);
1.562 + assert( pTable!=0 );
1.563 + if( pTable->pTrigger == pTrigger ){
1.564 + pTable->pTrigger = pTrigger->pNext;
1.565 + }else{
1.566 + Trigger *cc = pTable->pTrigger;
1.567 + while( cc ){
1.568 + if( cc->pNext == pTrigger ){
1.569 + cc->pNext = cc->pNext->pNext;
1.570 + break;
1.571 + }
1.572 + cc = cc->pNext;
1.573 + }
1.574 + assert(cc);
1.575 + }
1.576 + sqlite3DeleteTrigger(db, pTrigger);
1.577 + db->flags |= SQLITE_InternChanges;
1.578 + }
1.579 +}
1.580 +
1.581 +/*
1.582 +** pEList is the SET clause of an UPDATE statement. Each entry
1.583 +** in pEList is of the format <id>=<expr>. If any of the entries
1.584 +** in pEList have an <id> which matches an identifier in pIdList,
1.585 +** then return TRUE. If pIdList==NULL, then it is considered a
1.586 +** wildcard that matches anything. Likewise if pEList==NULL then
1.587 +** it matches anything so always return true. Return false only
1.588 +** if there is no match.
1.589 +*/
1.590 +static int checkColumnOverLap(IdList *pIdList, ExprList *pEList){
1.591 + int e;
1.592 + if( !pIdList || !pEList ) return 1;
1.593 + for(e=0; e<pEList->nExpr; e++){
1.594 + if( sqlite3IdListIndex(pIdList, pEList->a[e].zName)>=0 ) return 1;
1.595 + }
1.596 + return 0;
1.597 +}
1.598 +
1.599 +/*
1.600 +** Return a bit vector to indicate what kind of triggers exist for operation
1.601 +** "op" on table pTab. If pChanges is not NULL then it is a list of columns
1.602 +** that are being updated. Triggers only match if the ON clause of the
1.603 +** trigger definition overlaps the set of columns being updated.
1.604 +**
1.605 +** The returned bit vector is some combination of TRIGGER_BEFORE and
1.606 +** TRIGGER_AFTER.
1.607 +*/
1.608 +int sqlite3TriggersExist(
1.609 + Parse *pParse, /* Used to check for recursive triggers */
1.610 + Table *pTab, /* The table the contains the triggers */
1.611 + int op, /* one of TK_DELETE, TK_INSERT, TK_UPDATE */
1.612 + ExprList *pChanges /* Columns that change in an UPDATE statement */
1.613 +){
1.614 + Trigger *pTrigger;
1.615 + int mask = 0;
1.616 +
1.617 + pTrigger = IsVirtual(pTab) ? 0 : pTab->pTrigger;
1.618 + while( pTrigger ){
1.619 + if( pTrigger->op==op && checkColumnOverLap(pTrigger->pColumns, pChanges) ){
1.620 + mask |= pTrigger->tr_tm;
1.621 + }
1.622 + pTrigger = pTrigger->pNext;
1.623 + }
1.624 + return mask;
1.625 +}
1.626 +
1.627 +/*
1.628 +** Convert the pStep->target token into a SrcList and return a pointer
1.629 +** to that SrcList.
1.630 +**
1.631 +** This routine adds a specific database name, if needed, to the target when
1.632 +** forming the SrcList. This prevents a trigger in one database from
1.633 +** referring to a target in another database. An exception is when the
1.634 +** trigger is in TEMP in which case it can refer to any other database it
1.635 +** wants.
1.636 +*/
1.637 +static SrcList *targetSrcList(
1.638 + Parse *pParse, /* The parsing context */
1.639 + TriggerStep *pStep /* The trigger containing the target token */
1.640 +){
1.641 + Token sDb; /* Dummy database name token */
1.642 + int iDb; /* Index of the database to use */
1.643 + SrcList *pSrc; /* SrcList to be returned */
1.644 +
1.645 + iDb = sqlite3SchemaToIndex(pParse->db, pStep->pTrig->pSchema);
1.646 + if( iDb==0 || iDb>=2 ){
1.647 + assert( iDb<pParse->db->nDb );
1.648 + sDb.z = (u8*)pParse->db->aDb[iDb].zName;
1.649 + sDb.n = strlen((char*)sDb.z);
1.650 + pSrc = sqlite3SrcListAppend(pParse->db, 0, &sDb, &pStep->target);
1.651 + } else {
1.652 + pSrc = sqlite3SrcListAppend(pParse->db, 0, &pStep->target, 0);
1.653 + }
1.654 + return pSrc;
1.655 +}
1.656 +
1.657 +/*
1.658 +** Generate VDBE code for zero or more statements inside the body of a
1.659 +** trigger.
1.660 +*/
1.661 +static int codeTriggerProgram(
1.662 + Parse *pParse, /* The parser context */
1.663 + TriggerStep *pStepList, /* List of statements inside the trigger body */
1.664 + int orconfin /* Conflict algorithm. (OE_Abort, etc) */
1.665 +){
1.666 + TriggerStep * pTriggerStep = pStepList;
1.667 + int orconf;
1.668 + Vdbe *v = pParse->pVdbe;
1.669 + sqlite3 *db = pParse->db;
1.670 +
1.671 + assert( pTriggerStep!=0 );
1.672 + assert( v!=0 );
1.673 + sqlite3VdbeAddOp2(v, OP_ContextPush, 0, 0);
1.674 + VdbeComment((v, "begin trigger %s", pStepList->pTrig->name));
1.675 + while( pTriggerStep ){
1.676 + orconf = (orconfin == OE_Default)?pTriggerStep->orconf:orconfin;
1.677 + pParse->trigStack->orconf = orconf;
1.678 + switch( pTriggerStep->op ){
1.679 + case TK_SELECT: {
1.680 + Select *ss = sqlite3SelectDup(db, pTriggerStep->pSelect);
1.681 + if( ss ){
1.682 + SelectDest dest;
1.683 +
1.684 + sqlite3SelectDestInit(&dest, SRT_Discard, 0);
1.685 + sqlite3SelectResolve(pParse, ss, 0);
1.686 + sqlite3Select(pParse, ss, &dest, 0, 0, 0);
1.687 + sqlite3SelectDelete(db, ss);
1.688 + }
1.689 + break;
1.690 + }
1.691 + case TK_UPDATE: {
1.692 + SrcList *pSrc;
1.693 + pSrc = targetSrcList(pParse, pTriggerStep);
1.694 + sqlite3VdbeAddOp2(v, OP_ResetCount, 0, 0);
1.695 + sqlite3Update(pParse, pSrc,
1.696 + sqlite3ExprListDup(db, pTriggerStep->pExprList),
1.697 + sqlite3ExprDup(db, pTriggerStep->pWhere), orconf);
1.698 + sqlite3VdbeAddOp2(v, OP_ResetCount, 1, 0);
1.699 + break;
1.700 + }
1.701 + case TK_INSERT: {
1.702 + SrcList *pSrc;
1.703 + pSrc = targetSrcList(pParse, pTriggerStep);
1.704 + sqlite3VdbeAddOp2(v, OP_ResetCount, 0, 0);
1.705 + sqlite3Insert(pParse, pSrc,
1.706 + sqlite3ExprListDup(db, pTriggerStep->pExprList),
1.707 + sqlite3SelectDup(db, pTriggerStep->pSelect),
1.708 + sqlite3IdListDup(db, pTriggerStep->pIdList), orconf);
1.709 + sqlite3VdbeAddOp2(v, OP_ResetCount, 1, 0);
1.710 + break;
1.711 + }
1.712 + case TK_DELETE: {
1.713 + SrcList *pSrc;
1.714 + sqlite3VdbeAddOp2(v, OP_ResetCount, 0, 0);
1.715 + pSrc = targetSrcList(pParse, pTriggerStep);
1.716 + sqlite3DeleteFrom(pParse, pSrc,
1.717 + sqlite3ExprDup(db, pTriggerStep->pWhere));
1.718 + sqlite3VdbeAddOp2(v, OP_ResetCount, 1, 0);
1.719 + break;
1.720 + }
1.721 + default:
1.722 + assert(0);
1.723 + }
1.724 + pTriggerStep = pTriggerStep->pNext;
1.725 + }
1.726 + sqlite3VdbeAddOp2(v, OP_ContextPop, 0, 0);
1.727 + VdbeComment((v, "end trigger %s", pStepList->pTrig->name));
1.728 +
1.729 + return 0;
1.730 +}
1.731 +
1.732 +/*
1.733 +** This is called to code FOR EACH ROW triggers.
1.734 +**
1.735 +** When the code that this function generates is executed, the following
1.736 +** must be true:
1.737 +**
1.738 +** 1. No cursors may be open in the main database. (But newIdx and oldIdx
1.739 +** can be indices of cursors in temporary tables. See below.)
1.740 +**
1.741 +** 2. If the triggers being coded are ON INSERT or ON UPDATE triggers, then
1.742 +** a temporary vdbe cursor (index newIdx) must be open and pointing at
1.743 +** a row containing values to be substituted for new.* expressions in the
1.744 +** trigger program(s).
1.745 +**
1.746 +** 3. If the triggers being coded are ON DELETE or ON UPDATE triggers, then
1.747 +** a temporary vdbe cursor (index oldIdx) must be open and pointing at
1.748 +** a row containing values to be substituted for old.* expressions in the
1.749 +** trigger program(s).
1.750 +**
1.751 +** If they are not NULL, the piOldColMask and piNewColMask output variables
1.752 +** are set to values that describe the columns used by the trigger program
1.753 +** in the OLD.* and NEW.* tables respectively. If column N of the
1.754 +** pseudo-table is read at least once, the corresponding bit of the output
1.755 +** mask is set. If a column with an index greater than 32 is read, the
1.756 +** output mask is set to the special value 0xffffffff.
1.757 +**
1.758 +*/
1.759 +int sqlite3CodeRowTrigger(
1.760 + Parse *pParse, /* Parse context */
1.761 + int op, /* One of TK_UPDATE, TK_INSERT, TK_DELETE */
1.762 + ExprList *pChanges, /* Changes list for any UPDATE OF triggers */
1.763 + int tr_tm, /* One of TRIGGER_BEFORE, TRIGGER_AFTER */
1.764 + Table *pTab, /* The table to code triggers from */
1.765 + int newIdx, /* The indice of the "new" row to access */
1.766 + int oldIdx, /* The indice of the "old" row to access */
1.767 + int orconf, /* ON CONFLICT policy */
1.768 + int ignoreJump, /* Instruction to jump to for RAISE(IGNORE) */
1.769 + u32 *piOldColMask, /* OUT: Mask of columns used from the OLD.* table */
1.770 + u32 *piNewColMask /* OUT: Mask of columns used from the NEW.* table */
1.771 +){
1.772 + Trigger *p;
1.773 + sqlite3 *db = pParse->db;
1.774 + TriggerStack trigStackEntry;
1.775 +
1.776 + trigStackEntry.oldColMask = 0;
1.777 + trigStackEntry.newColMask = 0;
1.778 +
1.779 + assert(op == TK_UPDATE || op == TK_INSERT || op == TK_DELETE);
1.780 + assert(tr_tm == TRIGGER_BEFORE || tr_tm == TRIGGER_AFTER );
1.781 +
1.782 + assert(newIdx != -1 || oldIdx != -1);
1.783 +
1.784 + for(p=pTab->pTrigger; p; p=p->pNext){
1.785 + int fire_this = 0;
1.786 +
1.787 + /* Determine whether we should code this trigger */
1.788 + if(
1.789 + p->op==op &&
1.790 + p->tr_tm==tr_tm &&
1.791 + (p->pSchema==p->pTabSchema || p->pSchema==db->aDb[1].pSchema) &&
1.792 + (op!=TK_UPDATE||!p->pColumns||checkColumnOverLap(p->pColumns,pChanges))
1.793 + ){
1.794 + TriggerStack *pS; /* Pointer to trigger-stack entry */
1.795 + for(pS=pParse->trigStack; pS && p!=pS->pTrigger; pS=pS->pNext){}
1.796 + if( !pS ){
1.797 + fire_this = 1;
1.798 + }
1.799 +#if 0 /* Give no warning for recursive triggers. Just do not do them */
1.800 + else{
1.801 + sqlite3ErrorMsg(pParse, "recursive triggers not supported (%s)",
1.802 + p->name);
1.803 + return SQLITE_ERROR;
1.804 + }
1.805 +#endif
1.806 + }
1.807 +
1.808 + if( fire_this ){
1.809 + int endTrigger;
1.810 + Expr * whenExpr;
1.811 + AuthContext sContext;
1.812 + NameContext sNC;
1.813 +
1.814 +#ifndef SQLITE_OMIT_TRACE
1.815 + sqlite3VdbeAddOp4(pParse->pVdbe, OP_Trace, 0, 0, 0,
1.816 + sqlite3MPrintf(db, "-- TRIGGER %s", p->name),
1.817 + P4_DYNAMIC);
1.818 +#endif
1.819 + memset(&sNC, 0, sizeof(sNC));
1.820 + sNC.pParse = pParse;
1.821 +
1.822 + /* Push an entry on to the trigger stack */
1.823 + trigStackEntry.pTrigger = p;
1.824 + trigStackEntry.newIdx = newIdx;
1.825 + trigStackEntry.oldIdx = oldIdx;
1.826 + trigStackEntry.pTab = pTab;
1.827 + trigStackEntry.pNext = pParse->trigStack;
1.828 + trigStackEntry.ignoreJump = ignoreJump;
1.829 + pParse->trigStack = &trigStackEntry;
1.830 + sqlite3AuthContextPush(pParse, &sContext, p->name);
1.831 +
1.832 + /* code the WHEN clause */
1.833 + endTrigger = sqlite3VdbeMakeLabel(pParse->pVdbe);
1.834 + whenExpr = sqlite3ExprDup(db, p->pWhen);
1.835 + if( db->mallocFailed || sqlite3ExprResolveNames(&sNC, whenExpr) ){
1.836 + pParse->trigStack = trigStackEntry.pNext;
1.837 + sqlite3ExprDelete(db, whenExpr);
1.838 + return 1;
1.839 + }
1.840 + sqlite3ExprIfFalse(pParse, whenExpr, endTrigger, SQLITE_JUMPIFNULL);
1.841 + sqlite3ExprDelete(db, whenExpr);
1.842 +
1.843 + codeTriggerProgram(pParse, p->step_list, orconf);
1.844 +
1.845 + /* Pop the entry off the trigger stack */
1.846 + pParse->trigStack = trigStackEntry.pNext;
1.847 + sqlite3AuthContextPop(&sContext);
1.848 +
1.849 + sqlite3VdbeResolveLabel(pParse->pVdbe, endTrigger);
1.850 + }
1.851 + }
1.852 + if( piOldColMask ) *piOldColMask |= trigStackEntry.oldColMask;
1.853 + if( piNewColMask ) *piNewColMask |= trigStackEntry.newColMask;
1.854 + return 0;
1.855 +}
1.856 +#endif /* !defined(SQLITE_OMIT_TRIGGER) */