1 /* 2 ** 3 ** The author disclaims copyright to this source code. In place of 4 ** a legal notice, here is a blessing: 5 ** 6 ** May you do good and not evil. 7 ** May you find forgiveness for yourself and forgive others. 8 ** May you share freely, never taking more than you give. 9 ** 10 ************************************************************************* 11 * 12 */ 13 #include "sqliteInt.h" 14 15 /* 16 ** Delete a linked list of TriggerStep structures. 17 */ 18 void sqliteDeleteTriggerStep(TriggerStep *pTriggerStep){ 19 while( pTriggerStep ){ 20 TriggerStep * pTmp = pTriggerStep; 21 pTriggerStep = pTriggerStep->pNext; 22 23 if( pTmp->target.dyn ) sqliteFree((char*)pTmp->target.z); 24 sqliteExprDelete(pTmp->pWhere); 25 sqliteExprListDelete(pTmp->pExprList); 26 sqliteSelectDelete(pTmp->pSelect); 27 sqliteIdListDelete(pTmp->pIdList); 28 29 sqliteFree(pTmp); 30 } 31 } 32 33 /* 34 ** This is called by the parser when it sees a CREATE TRIGGER statement 35 ** up to the point of the BEGIN before the trigger actions. A Trigger 36 ** structure is generated based on the information available and stored 37 ** in pParse->pNewTrigger. After the trigger actions have been parsed, the 38 ** sqliteFinishTrigger() function is called to complete the trigger 39 ** construction process. 40 */ 41 void sqliteBeginTrigger( 42 Parse *pParse, /* The parse context of the CREATE TRIGGER statement */ 43 Token *pName, /* The name of the trigger */ 44 int tr_tm, /* One of TK_BEFORE, TK_AFTER, TK_INSTEAD */ 45 int op, /* One of TK_INSERT, TK_UPDATE, TK_DELETE */ 46 IdList *pColumns, /* column list if this is an UPDATE OF trigger */ 47 SrcList *pTableName,/* The name of the table/view the trigger applies to */ 48 int foreach, /* One of TK_ROW or TK_STATEMENT */ 49 Expr *pWhen, /* WHEN clause */ 50 int isTemp /* True if the TEMPORARY keyword is present */ 51 ){ 52 Trigger *nt; 53 Table *tab; 54 char *zName = 0; /* Name of the trigger */ 55 sqlite *db = pParse->db; 56 int iDb; /* When database to store the trigger in */ 57 DbFixer sFix; 58 59 /* Check that: 60 ** 1. the trigger name does not already exist. 61 ** 2. the table (or view) does exist in the same database as the trigger. 62 ** 3. that we are not trying to create a trigger on the sqlite_master table 63 ** 4. That we are not trying to create an INSTEAD OF trigger on a table. 64 ** 5. That we are not trying to create a BEFORE or AFTER trigger on a view. 65 */ 66 if( sqlite_malloc_failed ) goto trigger_cleanup; 67 assert( pTableName->nSrc==1 ); 68 if( db->init.busy 69 && sqliteFixInit(&sFix, pParse, db->init.iDb, "trigger", pName) 70 && sqliteFixSrcList(&sFix, pTableName) 71 ){ 72 goto trigger_cleanup; 73 } 74 tab = sqliteSrcListLookup(pParse, pTableName); 75 if( !tab ){ 76 goto trigger_cleanup; 77 } 78 iDb = isTemp ? 1 : tab->iDb; 79 if( iDb>=2 && !db->init.busy ){ 80 sqliteErrorMsg(pParse, "triggers may not be added to auxiliary " 81 "database %s", db->aDb[tab->iDb].zName); 82 goto trigger_cleanup; 83 } 84 85 zName = sqliteStrNDup(pName->z, pName->n); 86 sqliteDequote(zName); 87 if( sqliteHashFind(&(db->aDb[iDb].trigHash), zName,pName->n+1) ){ 88 sqliteErrorMsg(pParse, "trigger %T already exists", pName); 89 goto trigger_cleanup; 90 } 91 if( sqliteStrNICmp(tab->zName, "sqlite_", 7)==0 ){ 92 sqliteErrorMsg(pParse, "cannot create trigger on system table"); 93 pParse->nErr++; 94 goto trigger_cleanup; 95 } 96 if( tab->pSelect && tr_tm != TK_INSTEAD ){ 97 sqliteErrorMsg(pParse, "cannot create %s trigger on view: %S", 98 (tr_tm == TK_BEFORE)?"BEFORE":"AFTER", pTableName, 0); 99 goto trigger_cleanup; 100 } 101 if( !tab->pSelect && tr_tm == TK_INSTEAD ){ 102 sqliteErrorMsg(pParse, "cannot create INSTEAD OF" 103 " trigger on table: %S", pTableName, 0); 104 goto trigger_cleanup; 105 } 106 #ifndef SQLITE_OMIT_AUTHORIZATION 107 { 108 int code = SQLITE_CREATE_TRIGGER; 109 const char *zDb = db->aDb[tab->iDb].zName; 110 const char *zDbTrig = isTemp ? db->aDb[1].zName : zDb; 111 if( tab->iDb==1 || isTemp ) code = SQLITE_CREATE_TEMP_TRIGGER; 112 if( sqliteAuthCheck(pParse, code, zName, tab->zName, zDbTrig) ){ 113 goto trigger_cleanup; 114 } 115 if( sqliteAuthCheck(pParse, SQLITE_INSERT, SCHEMA_TABLE(tab->iDb), 0, zDb)){ 116 goto trigger_cleanup; 117 } 118 } 119 #endif 120 121 /* INSTEAD OF triggers can only appear on views and BEGIN triggers 122 ** cannot appear on views. So we might as well translate every 123 ** INSTEAD OF trigger into a BEFORE trigger. It simplifies code 124 ** elsewhere. 125 */ 126 if (tr_tm == TK_INSTEAD){ 127 tr_tm = TK_BEFORE; 128 } 129 130 /* Build the Trigger object */ 131 nt = (Trigger*)sqliteMalloc(sizeof(Trigger)); 132 if( nt==0 ) goto trigger_cleanup; 133 nt->name = zName; 134 zName = 0; 135 nt->table = sqliteStrDup(pTableName->a[0].zName); 136 if( sqlite_malloc_failed ) goto trigger_cleanup; 137 nt->iDb = iDb; 138 nt->iTabDb = tab->iDb; 139 nt->op = op; 140 nt->tr_tm = tr_tm; 141 nt->pWhen = sqliteExprDup(pWhen); 142 nt->pColumns = sqliteIdListDup(pColumns); 143 nt->foreach = foreach; 144 sqliteTokenCopy(&nt->nameToken,pName); 145 assert( pParse->pNewTrigger==0 ); 146 pParse->pNewTrigger = nt; 147 148 trigger_cleanup: 149 sqliteFree(zName); 150 sqliteSrcListDelete(pTableName); 151 sqliteIdListDelete(pColumns); 152 sqliteExprDelete(pWhen); 153 } 154 155 /* 156 ** This routine is called after all of the trigger actions have been parsed 157 ** in order to complete the process of building the trigger. 158 */ 159 void sqliteFinishTrigger( 160 Parse *pParse, /* Parser context */ 161 TriggerStep *pStepList, /* The triggered program */ 162 Token *pAll /* Token that describes the complete CREATE TRIGGER */ 163 ){ 164 Trigger *nt = 0; /* The trigger whose construction is finishing up */ 165 sqlite *db = pParse->db; /* The database */ 166 DbFixer sFix; 167 168 if( pParse->nErr || pParse->pNewTrigger==0 ) goto triggerfinish_cleanup; 169 nt = pParse->pNewTrigger; 170 pParse->pNewTrigger = 0; 171 nt->step_list = pStepList; 172 while( pStepList ){ 173 pStepList->pTrig = nt; 174 pStepList = pStepList->pNext; 175 } 176 if( sqliteFixInit(&sFix, pParse, nt->iDb, "trigger", &nt->nameToken) 177 && sqliteFixTriggerStep(&sFix, nt->step_list) ){ 178 goto triggerfinish_cleanup; 179 } 180 181 /* if we are not initializing, and this trigger is not on a TEMP table, 182 ** build the sqlite_master entry 183 */ 184 if( !db->init.busy ){ 185 static VdbeOpList insertTrig[] = { 186 { OP_NewRecno, 0, 0, 0 }, 187 { OP_String, 0, 0, "trigger" }, 188 { OP_String, 0, 0, 0 }, /* 2: trigger name */ 189 { OP_String, 0, 0, 0 }, /* 3: table name */ 190 { OP_Integer, 0, 0, 0 }, 191 { OP_String, 0, 0, 0 }, /* 5: SQL */ 192 { OP_MakeRecord, 5, 0, 0 }, 193 { OP_PutIntKey, 0, 0, 0 }, 194 }; 195 int addr; 196 Vdbe *v; 197 198 /* Make an entry in the sqlite_master table */ 199 v = sqliteGetVdbe(pParse); 200 if( v==0 ) goto triggerfinish_cleanup; 201 sqliteBeginWriteOperation(pParse, 0, 0); 202 sqliteOpenMasterTable(v, nt->iDb); 203 addr = sqliteVdbeAddOpList(v, ArraySize(insertTrig), insertTrig); 204 sqliteVdbeChangeP3(v, addr+2, nt->name, 0); 205 sqliteVdbeChangeP3(v, addr+3, nt->table, 0); 206 sqliteVdbeChangeP3(v, addr+5, pAll->z, pAll->n); 207 if( nt->iDb==0 ){ 208 sqliteChangeCookie(db, v); 209 } 210 sqliteVdbeAddOp(v, OP_Close, 0, 0); 211 sqliteEndWriteOperation(pParse); 212 } 213 214 if( !pParse->explain ){ 215 Table *pTab; 216 sqliteHashInsert(&db->aDb[nt->iDb].trigHash, 217 nt->name, strlen(nt->name)+1, nt); 218 pTab = sqliteLocateTable(pParse, nt->table, db->aDb[nt->iTabDb].zName); 219 assert( pTab!=0 ); 220 nt->pNext = pTab->pTrigger; 221 pTab->pTrigger = nt; 222 nt = 0; 223 } 224 225 triggerfinish_cleanup: 226 sqliteDeleteTrigger(nt); 227 sqliteDeleteTrigger(pParse->pNewTrigger); 228 pParse->pNewTrigger = 0; 229 sqliteDeleteTriggerStep(pStepList); 230 } 231 232 /* 233 ** Make a copy of all components of the given trigger step. This has 234 ** the effect of copying all Expr.token.z values into memory obtained 235 ** from sqliteMalloc(). As initially created, the Expr.token.z values 236 ** all point to the input string that was fed to the parser. But that 237 ** string is ephemeral - it will go away as soon as the sqlite_exec() 238 ** call that started the parser exits. This routine makes a persistent 239 ** copy of all the Expr.token.z strings so that the TriggerStep structure 240 ** will be valid even after the sqlite_exec() call returns. 241 */ 242 static void sqlitePersistTriggerStep(TriggerStep *p){ 243 if( p->target.z ){ 244 p->target.z = sqliteStrNDup(p->target.z, p->target.n); 245 p->target.dyn = 1; 246 } 247 if( p->pSelect ){ 248 Select *pNew = sqliteSelectDup(p->pSelect); 249 sqliteSelectDelete(p->pSelect); 250 p->pSelect = pNew; 251 } 252 if( p->pWhere ){ 253 Expr *pNew = sqliteExprDup(p->pWhere); 254 sqliteExprDelete(p->pWhere); 255 p->pWhere = pNew; 256 } 257 if( p->pExprList ){ 258 ExprList *pNew = sqliteExprListDup(p->pExprList); 259 sqliteExprListDelete(p->pExprList); 260 p->pExprList = pNew; 261 } 262 if( p->pIdList ){ 263 IdList *pNew = sqliteIdListDup(p->pIdList); 264 sqliteIdListDelete(p->pIdList); 265 p->pIdList = pNew; 266 } 267 } 268 269 /* 270 ** Turn a SELECT statement (that the pSelect parameter points to) into 271 ** a trigger step. Return a pointer to a TriggerStep structure. 272 ** 273 ** The parser calls this routine when it finds a SELECT statement in 274 ** body of a TRIGGER. 275 */ 276 TriggerStep *sqliteTriggerSelectStep(Select *pSelect){ 277 TriggerStep *pTriggerStep = sqliteMalloc(sizeof(TriggerStep)); 278 if( pTriggerStep==0 ) return 0; 279 280 pTriggerStep->op = TK_SELECT; 281 pTriggerStep->pSelect = pSelect; 282 pTriggerStep->orconf = OE_Default; 283 sqlitePersistTriggerStep(pTriggerStep); 284 285 return pTriggerStep; 286 } 287 288 /* 289 ** Build a trigger step out of an INSERT statement. Return a pointer 290 ** to the new trigger step. 291 ** 292 ** The parser calls this routine when it sees an INSERT inside the 293 ** body of a trigger. 294 */ 295 TriggerStep *sqliteTriggerInsertStep( 296 Token *pTableName, /* Name of the table into which we insert */ 297 IdList *pColumn, /* List of columns in pTableName to insert into */ 298 ExprList *pEList, /* The VALUE clause: a list of values to be inserted */ 299 Select *pSelect, /* A SELECT statement that supplies values */ 300 int orconf /* The conflict algorithm (OE_Abort, OE_Replace, etc.) */ 301 ){ 302 TriggerStep *pTriggerStep = sqliteMalloc(sizeof(TriggerStep)); 303 if( pTriggerStep==0 ) return 0; 304 305 assert(pEList == 0 || pSelect == 0); 306 assert(pEList != 0 || pSelect != 0); 307 308 pTriggerStep->op = TK_INSERT; 309 pTriggerStep->pSelect = pSelect; 310 pTriggerStep->target = *pTableName; 311 pTriggerStep->pIdList = pColumn; 312 pTriggerStep->pExprList = pEList; 313 pTriggerStep->orconf = orconf; 314 sqlitePersistTriggerStep(pTriggerStep); 315 316 return pTriggerStep; 317 } 318 319 /* 320 ** Construct a trigger step that implements an UPDATE statement and return 321 ** a pointer to that trigger step. The parser calls this routine when it 322 ** sees an UPDATE statement inside the body of a CREATE TRIGGER. 323 */ 324 TriggerStep *sqliteTriggerUpdateStep( 325 Token *pTableName, /* Name of the table to be updated */ 326 ExprList *pEList, /* The SET clause: list of column and new values */ 327 Expr *pWhere, /* The WHERE clause */ 328 int orconf /* The conflict algorithm. (OE_Abort, OE_Ignore, etc) */ 329 ){ 330 TriggerStep *pTriggerStep = sqliteMalloc(sizeof(TriggerStep)); 331 if( pTriggerStep==0 ) return 0; 332 333 pTriggerStep->op = TK_UPDATE; 334 pTriggerStep->target = *pTableName; 335 pTriggerStep->pExprList = pEList; 336 pTriggerStep->pWhere = pWhere; 337 pTriggerStep->orconf = orconf; 338 sqlitePersistTriggerStep(pTriggerStep); 339 340 return pTriggerStep; 341 } 342 343 /* 344 ** Construct a trigger step that implements a DELETE statement and return 345 ** a pointer to that trigger step. The parser calls this routine when it 346 ** sees a DELETE statement inside the body of a CREATE TRIGGER. 347 */ 348 TriggerStep *sqliteTriggerDeleteStep(Token *pTableName, Expr *pWhere){ 349 TriggerStep *pTriggerStep = sqliteMalloc(sizeof(TriggerStep)); 350 if( pTriggerStep==0 ) return 0; 351 352 pTriggerStep->op = TK_DELETE; 353 pTriggerStep->target = *pTableName; 354 pTriggerStep->pWhere = pWhere; 355 pTriggerStep->orconf = OE_Default; 356 sqlitePersistTriggerStep(pTriggerStep); 357 358 return pTriggerStep; 359 } 360 361 /* 362 ** Recursively delete a Trigger structure 363 */ 364 void sqliteDeleteTrigger(Trigger *pTrigger){ 365 if( pTrigger==0 ) return; 366 sqliteDeleteTriggerStep(pTrigger->step_list); 367 sqliteFree(pTrigger->name); 368 sqliteFree(pTrigger->table); 369 sqliteExprDelete(pTrigger->pWhen); 370 sqliteIdListDelete(pTrigger->pColumns); 371 if( pTrigger->nameToken.dyn ) sqliteFree((char*)pTrigger->nameToken.z); 372 sqliteFree(pTrigger); 373 } 374 375 /* 376 * This function is called to drop a trigger from the database schema. 377 * 378 * This may be called directly from the parser and therefore identifies 379 * the trigger by name. The sqliteDropTriggerPtr() routine does the 380 * same job as this routine except it take a spointer to the trigger 381 * instead of the trigger name. 382 * 383 * Note that this function does not delete the trigger entirely. Instead it 384 * removes it from the internal schema and places it in the trigDrop hash 385 * table. This is so that the trigger can be restored into the database schema 386 * if the transaction is rolled back. 387 */ 388 void sqliteDropTrigger(Parse *pParse, SrcList *pName){ 389 Trigger *pTrigger; 390 int i; 391 const char *zDb; 392 const char *zName; 393 int nName; 394 sqlite *db = pParse->db; 395 396 if( sqlite_malloc_failed ) goto drop_trigger_cleanup; 397 assert( pName->nSrc==1 ); 398 zDb = pName->a[0].zDatabase; 399 zName = pName->a[0].zName; 400 nName = strlen(zName); 401 for(i=0; i<db->nDb; i++){ 402 int j = (i<2) ? i^1 : i; /* Search TEMP before MAIN */ 403 if( zDb && sqliteStrICmp(db->aDb[j].zName, zDb) ) continue; 404 pTrigger = sqliteHashFind(&(db->aDb[j].trigHash), zName, nName+1); 405 if( pTrigger ) break; 406 } 407 if( !pTrigger ){ 408 sqliteErrorMsg(pParse, "no such trigger: %S", pName, 0); 409 goto drop_trigger_cleanup; 410 } 411 sqliteDropTriggerPtr(pParse, pTrigger, 0); 412 413 drop_trigger_cleanup: 414 sqliteSrcListDelete(pName); 415 } 416 417 /* 418 ** Drop a trigger given a pointer to that trigger. If nested is false, 419 ** then also generate code to remove the trigger from the SQLITE_MASTER 420 ** table. 421 */ 422 void sqliteDropTriggerPtr(Parse *pParse, Trigger *pTrigger, int nested){ 423 Table *pTable; 424 Vdbe *v; 425 sqlite *db = pParse->db; 426 427 assert( pTrigger->iDb<db->nDb ); 428 if( pTrigger->iDb>=2 ){ 429 sqliteErrorMsg(pParse, "triggers may not be removed from " 430 "auxiliary database %s", db->aDb[pTrigger->iDb].zName); 431 return; 432 } 433 pTable = sqliteFindTable(db, pTrigger->table,db->aDb[pTrigger->iTabDb].zName); 434 assert(pTable); 435 assert( pTable->iDb==pTrigger->iDb || pTrigger->iDb==1 ); 436 #ifndef SQLITE_OMIT_AUTHORIZATION 437 { 438 int code = SQLITE_DROP_TRIGGER; 439 const char *zDb = db->aDb[pTrigger->iDb].zName; 440 const char *zTab = SCHEMA_TABLE(pTrigger->iDb); 441 if( pTrigger->iDb ) code = SQLITE_DROP_TEMP_TRIGGER; 442 if( sqliteAuthCheck(pParse, code, pTrigger->name, pTable->zName, zDb) || 443 sqliteAuthCheck(pParse, SQLITE_DELETE, zTab, 0, zDb) ){ 444 return; 445 } 446 } 447 #endif 448 449 /* Generate code to destroy the database record of the trigger. 450 */ 451 if( pTable!=0 && !nested && (v = sqliteGetVdbe(pParse))!=0 ){ 452 int base; 453 static VdbeOpList dropTrigger[] = { 454 { OP_Rewind, 0, ADDR(9), 0}, 455 { OP_String, 0, 0, 0}, /* 1 */ 456 { OP_Column, 0, 1, 0}, 457 { OP_Ne, 0, ADDR(8), 0}, 458 { OP_String, 0, 0, "trigger"}, 459 { OP_Column, 0, 0, 0}, 460 { OP_Ne, 0, ADDR(8), 0}, 461 { OP_Delete, 0, 0, 0}, 462 { OP_Next, 0, ADDR(1), 0}, /* 8 */ 463 }; 464 465 sqliteBeginWriteOperation(pParse, 0, 0); 466 sqliteOpenMasterTable(v, pTrigger->iDb); 467 base = sqliteVdbeAddOpList(v, ArraySize(dropTrigger), dropTrigger); 468 sqliteVdbeChangeP3(v, base+1, pTrigger->name, 0); 469 if( pTrigger->iDb==0 ){ 470 sqliteChangeCookie(db, v); 471 } 472 sqliteVdbeAddOp(v, OP_Close, 0, 0); 473 sqliteEndWriteOperation(pParse); 474 } 475 476 /* 477 * If this is not an "explain", then delete the trigger structure. 478 */ 479 if( !pParse->explain ){ 480 const char *zName = pTrigger->name; 481 int nName = strlen(zName); 482 if( pTable->pTrigger == pTrigger ){ 483 pTable->pTrigger = pTrigger->pNext; 484 }else{ 485 Trigger *cc = pTable->pTrigger; 486 while( cc ){ 487 if( cc->pNext == pTrigger ){ 488 cc->pNext = cc->pNext->pNext; 489 break; 490 } 491 cc = cc->pNext; 492 } 493 assert(cc); 494 } 495 sqliteHashInsert(&(db->aDb[pTrigger->iDb].trigHash), zName, nName+1, 0); 496 sqliteDeleteTrigger(pTrigger); 497 } 498 } 499 500 /* 501 ** pEList is the SET clause of an UPDATE statement. Each entry 502 ** in pEList is of the format <id>=<expr>. If any of the entries 503 ** in pEList have an <id> which matches an identifier in pIdList, 504 ** then return TRUE. If pIdList==NULL, then it is considered a 505 ** wildcard that matches anything. Likewise if pEList==NULL then 506 ** it matches anything so always return true. Return false only 507 ** if there is no match. 508 */ 509 static int checkColumnOverLap(IdList *pIdList, ExprList *pEList){ 510 int e; 511 if( !pIdList || !pEList ) return 1; 512 for(e=0; e<pEList->nExpr; e++){ 513 if( sqliteIdListIndex(pIdList, pEList->a[e].zName)>=0 ) return 1; 514 } 515 return 0; 516 } 517 518 /* A global variable that is TRUE if we should always set up temp tables for 519 * for triggers, even if there are no triggers to code. This is used to test 520 * how much overhead the triggers algorithm is causing. 521 * 522 * This flag can be set or cleared using the "trigger_overhead_test" pragma. 523 * The pragma is not documented since it is not really part of the interface 524 * to SQLite, just the test procedure. 525 */ 526 int always_code_trigger_setup = 0; 527 528 /* 529 * Returns true if a trigger matching op, tr_tm and foreach that is NOT already 530 * on the Parse objects trigger-stack (to prevent recursive trigger firing) is 531 * found in the list specified as pTrigger. 532 */ 533 int sqliteTriggersExist( 534 Parse *pParse, /* Used to check for recursive triggers */ 535 Trigger *pTrigger, /* A list of triggers associated with a table */ 536 int op, /* one of TK_DELETE, TK_INSERT, TK_UPDATE */ 537 int tr_tm, /* one of TK_BEFORE, TK_AFTER */ 538 int foreach, /* one of TK_ROW or TK_STATEMENT */ 539 ExprList *pChanges /* Columns that change in an UPDATE statement */ 540 ){ 541 Trigger * pTriggerCursor; 542 543 if( always_code_trigger_setup ){ 544 return 1; 545 } 546 547 pTriggerCursor = pTrigger; 548 while( pTriggerCursor ){ 549 if( pTriggerCursor->op == op && 550 pTriggerCursor->tr_tm == tr_tm && 551 pTriggerCursor->foreach == foreach && 552 checkColumnOverLap(pTriggerCursor->pColumns, pChanges) ){ 553 TriggerStack * ss; 554 ss = pParse->trigStack; 555 while( ss && ss->pTrigger != pTrigger ){ 556 ss = ss->pNext; 557 } 558 if( !ss )return 1; 559 } 560 pTriggerCursor = pTriggerCursor->pNext; 561 } 562 563 return 0; 564 } 565 566 /* 567 ** Convert the pStep->target token into a SrcList and return a pointer 568 ** to that SrcList. 569 ** 570 ** This routine adds a specific database name, if needed, to the target when 571 ** forming the SrcList. This prevents a trigger in one database from 572 ** referring to a target in another database. An exception is when the 573 ** trigger is in TEMP in which case it can refer to any other database it 574 ** wants. 575 */ 576 static SrcList *targetSrcList( 577 Parse *pParse, /* The parsing context */ 578 TriggerStep *pStep /* The trigger containing the target token */ 579 ){ 580 Token sDb; /* Dummy database name token */ 581 int iDb; /* Index of the database to use */ 582 SrcList *pSrc; /* SrcList to be returned */ 583 584 iDb = pStep->pTrig->iDb; 585 if( iDb==0 || iDb>=2 ){ 586 assert( iDb<pParse->db->nDb ); 587 sDb.z = pParse->db->aDb[iDb].zName; 588 sDb.n = strlen(sDb.z); 589 pSrc = sqliteSrcListAppend(0, &sDb, &pStep->target); 590 } else { 591 pSrc = sqliteSrcListAppend(0, &pStep->target, 0); 592 } 593 return pSrc; 594 } 595 596 /* 597 ** Generate VDBE code for zero or more statements inside the body of a 598 ** trigger. 599 */ 600 static int codeTriggerProgram( 601 Parse *pParse, /* The parser context */ 602 TriggerStep *pStepList, /* List of statements inside the trigger body */ 603 int orconfin /* Conflict algorithm. (OE_Abort, etc) */ 604 ){ 605 TriggerStep * pTriggerStep = pStepList; 606 int orconf; 607 608 while( pTriggerStep ){ 609 int saveNTab = pParse->nTab; 610 611 orconf = (orconfin == OE_Default)?pTriggerStep->orconf:orconfin; 612 pParse->trigStack->orconf = orconf; 613 switch( pTriggerStep->op ){ 614 case TK_SELECT: { 615 Select * ss = sqliteSelectDup(pTriggerStep->pSelect); 616 assert(ss); 617 assert(ss->pSrc); 618 sqliteSelect(pParse, ss, SRT_Discard, 0, 0, 0, 0); 619 sqliteSelectDelete(ss); 620 break; 621 } 622 case TK_UPDATE: { 623 SrcList *pSrc; 624 pSrc = targetSrcList(pParse, pTriggerStep); 625 sqliteVdbeAddOp(pParse->pVdbe, OP_ListPush, 0, 0); 626 sqliteUpdate(pParse, pSrc, 627 sqliteExprListDup(pTriggerStep->pExprList), 628 sqliteExprDup(pTriggerStep->pWhere), orconf); 629 sqliteVdbeAddOp(pParse->pVdbe, OP_ListPop, 0, 0); 630 break; 631 } 632 case TK_INSERT: { 633 SrcList *pSrc; 634 pSrc = targetSrcList(pParse, pTriggerStep); 635 sqliteInsert(pParse, pSrc, 636 sqliteExprListDup(pTriggerStep->pExprList), 637 sqliteSelectDup(pTriggerStep->pSelect), 638 sqliteIdListDup(pTriggerStep->pIdList), orconf); 639 break; 640 } 641 case TK_DELETE: { 642 SrcList *pSrc; 643 sqliteVdbeAddOp(pParse->pVdbe, OP_ListPush, 0, 0); 644 pSrc = targetSrcList(pParse, pTriggerStep); 645 sqliteDeleteFrom(pParse, pSrc, sqliteExprDup(pTriggerStep->pWhere)); 646 sqliteVdbeAddOp(pParse->pVdbe, OP_ListPop, 0, 0); 647 break; 648 } 649 default: 650 assert(0); 651 } 652 pParse->nTab = saveNTab; 653 pTriggerStep = pTriggerStep->pNext; 654 } 655 656 return 0; 657 } 658 659 /* 660 ** This is called to code FOR EACH ROW triggers. 661 ** 662 ** When the code that this function generates is executed, the following 663 ** must be true: 664 ** 665 ** 1. No cursors may be open in the main database. (But newIdx and oldIdx 666 ** can be indices of cursors in temporary tables. See below.) 667 ** 668 ** 2. If the triggers being coded are ON INSERT or ON UPDATE triggers, then 669 ** a temporary vdbe cursor (index newIdx) must be open and pointing at 670 ** a row containing values to be substituted for new.* expressions in the 671 ** trigger program(s). 672 ** 673 ** 3. If the triggers being coded are ON DELETE or ON UPDATE triggers, then 674 ** a temporary vdbe cursor (index oldIdx) must be open and pointing at 675 ** a row containing values to be substituted for old.* expressions in the 676 ** trigger program(s). 677 ** 678 */ 679 int sqliteCodeRowTrigger( 680 Parse *pParse, /* Parse context */ 681 int op, /* One of TK_UPDATE, TK_INSERT, TK_DELETE */ 682 ExprList *pChanges, /* Changes list for any UPDATE OF triggers */ 683 int tr_tm, /* One of TK_BEFORE, TK_AFTER */ 684 Table *pTab, /* The table to code triggers from */ 685 int newIdx, /* The indice of the "new" row to access */ 686 int oldIdx, /* The indice of the "old" row to access */ 687 int orconf, /* ON CONFLICT policy */ 688 int ignoreJump /* Instruction to jump to for RAISE(IGNORE) */ 689 ){ 690 Trigger * pTrigger; 691 TriggerStack * pTriggerStack; 692 693 assert(op == TK_UPDATE || op == TK_INSERT || op == TK_DELETE); 694 assert(tr_tm == TK_BEFORE || tr_tm == TK_AFTER ); 695 696 assert(newIdx != -1 || oldIdx != -1); 697 698 pTrigger = pTab->pTrigger; 699 while( pTrigger ){ 700 int fire_this = 0; 701 702 /* determine whether we should code this trigger */ 703 if( pTrigger->op == op && pTrigger->tr_tm == tr_tm && 704 pTrigger->foreach == TK_ROW ){ 705 fire_this = 1; 706 pTriggerStack = pParse->trigStack; 707 while( pTriggerStack ){ 708 if( pTriggerStack->pTrigger == pTrigger ){ 709 fire_this = 0; 710 } 711 pTriggerStack = pTriggerStack->pNext; 712 } 713 if( op == TK_UPDATE && pTrigger->pColumns && 714 !checkColumnOverLap(pTrigger->pColumns, pChanges) ){ 715 fire_this = 0; 716 } 717 } 718 719 if( fire_this && (pTriggerStack = sqliteMalloc(sizeof(TriggerStack)))!=0 ){ 720 int endTrigger; 721 SrcList dummyTablist; 722 Expr * whenExpr; 723 AuthContext sContext; 724 725 dummyTablist.nSrc = 0; 726 727 /* Push an entry on to the trigger stack */ 728 pTriggerStack->pTrigger = pTrigger; 729 pTriggerStack->newIdx = newIdx; 730 pTriggerStack->oldIdx = oldIdx; 731 pTriggerStack->pTab = pTab; 732 pTriggerStack->pNext = pParse->trigStack; 733 pTriggerStack->ignoreJump = ignoreJump; 734 pParse->trigStack = pTriggerStack; 735 sqliteAuthContextPush(pParse, &sContext, pTrigger->name); 736 737 /* code the WHEN clause */ 738 endTrigger = sqliteVdbeMakeLabel(pParse->pVdbe); 739 whenExpr = sqliteExprDup(pTrigger->pWhen); 740 if( sqliteExprResolveIds(pParse, &dummyTablist, 0, whenExpr) ){ 741 pParse->trigStack = pParse->trigStack->pNext; 742 sqliteFree(pTriggerStack); 743 sqliteExprDelete(whenExpr); 744 return 1; 745 } 746 sqliteExprIfFalse(pParse, whenExpr, endTrigger, 1); 747 sqliteExprDelete(whenExpr); 748 749 sqliteVdbeAddOp(pParse->pVdbe, OP_ContextPush, 0, 0); 750 codeTriggerProgram(pParse, pTrigger->step_list, orconf); 751 sqliteVdbeAddOp(pParse->pVdbe, OP_ContextPop, 0, 0); 752 753 /* Pop the entry off the trigger stack */ 754 pParse->trigStack = pParse->trigStack->pNext; 755 sqliteAuthContextPop(&sContext); 756 sqliteFree(pTriggerStack); 757 758 sqliteVdbeResolveLabel(pParse->pVdbe, endTrigger); 759 } 760 pTrigger = pTrigger->pNext; 761 } 762 763 return 0; 764 } 765