1
2 #pragma ident "%Z%%M% %I% %E% SMI"
3
4 /*
5 **
6 ** The author disclaims copyright to this source code. In place of
7 ** a legal notice, here is a blessing:
8 **
9 ** May you do good and not evil.
10 ** May you find forgiveness for yourself and forgive others.
11 ** May you share freely, never taking more than you give.
12 **
13 *************************************************************************
14 *
15 */
16 #include "sqliteInt.h"
17
18 /*
19 ** Delete a linked list of TriggerStep structures.
20 */
sqliteDeleteTriggerStep(TriggerStep * pTriggerStep)21 void sqliteDeleteTriggerStep(TriggerStep *pTriggerStep){
22 while( pTriggerStep ){
23 TriggerStep * pTmp = pTriggerStep;
24 pTriggerStep = pTriggerStep->pNext;
25
26 if( pTmp->target.dyn ) sqliteFree((char*)pTmp->target.z);
27 sqliteExprDelete(pTmp->pWhere);
28 sqliteExprListDelete(pTmp->pExprList);
29 sqliteSelectDelete(pTmp->pSelect);
30 sqliteIdListDelete(pTmp->pIdList);
31
32 sqliteFree(pTmp);
33 }
34 }
35
36 /*
37 ** This is called by the parser when it sees a CREATE TRIGGER statement
38 ** up to the point of the BEGIN before the trigger actions. A Trigger
39 ** structure is generated based on the information available and stored
40 ** in pParse->pNewTrigger. After the trigger actions have been parsed, the
41 ** sqliteFinishTrigger() function is called to complete the trigger
42 ** construction process.
43 */
sqliteBeginTrigger(Parse * pParse,Token * pName,int tr_tm,int op,IdList * pColumns,SrcList * pTableName,int foreach,Expr * pWhen,int isTemp)44 void sqliteBeginTrigger(
45 Parse *pParse, /* The parse context of the CREATE TRIGGER statement */
46 Token *pName, /* The name of the trigger */
47 int tr_tm, /* One of TK_BEFORE, TK_AFTER, TK_INSTEAD */
48 int op, /* One of TK_INSERT, TK_UPDATE, TK_DELETE */
49 IdList *pColumns, /* column list if this is an UPDATE OF trigger */
50 SrcList *pTableName,/* The name of the table/view the trigger applies to */
51 int foreach, /* One of TK_ROW or TK_STATEMENT */
52 Expr *pWhen, /* WHEN clause */
53 int isTemp /* True if the TEMPORARY keyword is present */
54 ){
55 Trigger *nt;
56 Table *tab;
57 char *zName = 0; /* Name of the trigger */
58 sqlite *db = pParse->db;
59 int iDb; /* When database to store the trigger in */
60 DbFixer sFix;
61
62 /* Check that:
63 ** 1. the trigger name does not already exist.
64 ** 2. the table (or view) does exist in the same database as the trigger.
65 ** 3. that we are not trying to create a trigger on the sqlite_master table
66 ** 4. That we are not trying to create an INSTEAD OF trigger on a table.
67 ** 5. That we are not trying to create a BEFORE or AFTER trigger on a view.
68 */
69 if( sqlite_malloc_failed ) goto trigger_cleanup;
70 assert( pTableName->nSrc==1 );
71 if( db->init.busy
72 && sqliteFixInit(&sFix, pParse, db->init.iDb, "trigger", pName)
73 && sqliteFixSrcList(&sFix, pTableName)
74 ){
75 goto trigger_cleanup;
76 }
77 tab = sqliteSrcListLookup(pParse, pTableName);
78 if( !tab ){
79 goto trigger_cleanup;
80 }
81 iDb = isTemp ? 1 : tab->iDb;
82 if( iDb>=2 && !db->init.busy ){
83 sqliteErrorMsg(pParse, "triggers may not be added to auxiliary "
84 "database %s", db->aDb[tab->iDb].zName);
85 goto trigger_cleanup;
86 }
87
88 zName = sqliteStrNDup(pName->z, pName->n);
89 sqliteDequote(zName);
90 if( sqliteHashFind(&(db->aDb[iDb].trigHash), zName,pName->n+1) ){
91 sqliteErrorMsg(pParse, "trigger %T already exists", pName);
92 goto trigger_cleanup;
93 }
94 if( sqliteStrNICmp(tab->zName, "sqlite_", 7)==0 ){
95 sqliteErrorMsg(pParse, "cannot create trigger on system table");
96 pParse->nErr++;
97 goto trigger_cleanup;
98 }
99 if( tab->pSelect && tr_tm != TK_INSTEAD ){
100 sqliteErrorMsg(pParse, "cannot create %s trigger on view: %S",
101 (tr_tm == TK_BEFORE)?"BEFORE":"AFTER", pTableName, 0);
102 goto trigger_cleanup;
103 }
104 if( !tab->pSelect && tr_tm == TK_INSTEAD ){
105 sqliteErrorMsg(pParse, "cannot create INSTEAD OF"
106 " trigger on table: %S", pTableName, 0);
107 goto trigger_cleanup;
108 }
109 #ifndef SQLITE_OMIT_AUTHORIZATION
110 {
111 int code = SQLITE_CREATE_TRIGGER;
112 const char *zDb = db->aDb[tab->iDb].zName;
113 const char *zDbTrig = isTemp ? db->aDb[1].zName : zDb;
114 if( tab->iDb==1 || isTemp ) code = SQLITE_CREATE_TEMP_TRIGGER;
115 if( sqliteAuthCheck(pParse, code, zName, tab->zName, zDbTrig) ){
116 goto trigger_cleanup;
117 }
118 if( sqliteAuthCheck(pParse, SQLITE_INSERT, SCHEMA_TABLE(tab->iDb), 0, zDb)){
119 goto trigger_cleanup;
120 }
121 }
122 #endif
123
124 /* INSTEAD OF triggers can only appear on views and BEGIN triggers
125 ** cannot appear on views. So we might as well translate every
126 ** INSTEAD OF trigger into a BEFORE trigger. It simplifies code
127 ** elsewhere.
128 */
129 if (tr_tm == TK_INSTEAD){
130 tr_tm = TK_BEFORE;
131 }
132
133 /* Build the Trigger object */
134 nt = (Trigger*)sqliteMalloc(sizeof(Trigger));
135 if( nt==0 ) goto trigger_cleanup;
136 nt->name = zName;
137 zName = 0;
138 nt->table = sqliteStrDup(pTableName->a[0].zName);
139 if( sqlite_malloc_failed ) goto trigger_cleanup;
140 nt->iDb = iDb;
141 nt->iTabDb = tab->iDb;
142 nt->op = op;
143 nt->tr_tm = tr_tm;
144 nt->pWhen = sqliteExprDup(pWhen);
145 nt->pColumns = sqliteIdListDup(pColumns);
146 nt->foreach = foreach;
147 sqliteTokenCopy(&nt->nameToken,pName);
148 assert( pParse->pNewTrigger==0 );
149 pParse->pNewTrigger = nt;
150
151 trigger_cleanup:
152 sqliteFree(zName);
153 sqliteSrcListDelete(pTableName);
154 sqliteIdListDelete(pColumns);
155 sqliteExprDelete(pWhen);
156 }
157
158 /*
159 ** This routine is called after all of the trigger actions have been parsed
160 ** in order to complete the process of building the trigger.
161 */
sqliteFinishTrigger(Parse * pParse,TriggerStep * pStepList,Token * pAll)162 void sqliteFinishTrigger(
163 Parse *pParse, /* Parser context */
164 TriggerStep *pStepList, /* The triggered program */
165 Token *pAll /* Token that describes the complete CREATE TRIGGER */
166 ){
167 Trigger *nt = 0; /* The trigger whose construction is finishing up */
168 sqlite *db = pParse->db; /* The database */
169 DbFixer sFix;
170
171 if( pParse->nErr || pParse->pNewTrigger==0 ) goto triggerfinish_cleanup;
172 nt = pParse->pNewTrigger;
173 pParse->pNewTrigger = 0;
174 nt->step_list = pStepList;
175 while( pStepList ){
176 pStepList->pTrig = nt;
177 pStepList = pStepList->pNext;
178 }
179 if( sqliteFixInit(&sFix, pParse, nt->iDb, "trigger", &nt->nameToken)
180 && sqliteFixTriggerStep(&sFix, nt->step_list) ){
181 goto triggerfinish_cleanup;
182 }
183
184 /* if we are not initializing, and this trigger is not on a TEMP table,
185 ** build the sqlite_master entry
186 */
187 if( !db->init.busy ){
188 static VdbeOpList insertTrig[] = {
189 { OP_NewRecno, 0, 0, 0 },
190 { OP_String, 0, 0, "trigger" },
191 { OP_String, 0, 0, 0 }, /* 2: trigger name */
192 { OP_String, 0, 0, 0 }, /* 3: table name */
193 { OP_Integer, 0, 0, 0 },
194 { OP_String, 0, 0, 0 }, /* 5: SQL */
195 { OP_MakeRecord, 5, 0, 0 },
196 { OP_PutIntKey, 0, 0, 0 },
197 };
198 int addr;
199 Vdbe *v;
200
201 /* Make an entry in the sqlite_master table */
202 v = sqliteGetVdbe(pParse);
203 if( v==0 ) goto triggerfinish_cleanup;
204 sqliteBeginWriteOperation(pParse, 0, 0);
205 sqliteOpenMasterTable(v, nt->iDb);
206 addr = sqliteVdbeAddOpList(v, ArraySize(insertTrig), insertTrig);
207 sqliteVdbeChangeP3(v, addr+2, nt->name, 0);
208 sqliteVdbeChangeP3(v, addr+3, nt->table, 0);
209 sqliteVdbeChangeP3(v, addr+5, pAll->z, pAll->n);
210 if( nt->iDb==0 ){
211 sqliteChangeCookie(db, v);
212 }
213 sqliteVdbeAddOp(v, OP_Close, 0, 0);
214 sqliteEndWriteOperation(pParse);
215 }
216
217 if( !pParse->explain ){
218 Table *pTab;
219 sqliteHashInsert(&db->aDb[nt->iDb].trigHash,
220 nt->name, strlen(nt->name)+1, nt);
221 pTab = sqliteLocateTable(pParse, nt->table, db->aDb[nt->iTabDb].zName);
222 assert( pTab!=0 );
223 nt->pNext = pTab->pTrigger;
224 pTab->pTrigger = nt;
225 nt = 0;
226 }
227
228 triggerfinish_cleanup:
229 sqliteDeleteTrigger(nt);
230 sqliteDeleteTrigger(pParse->pNewTrigger);
231 pParse->pNewTrigger = 0;
232 sqliteDeleteTriggerStep(pStepList);
233 }
234
235 /*
236 ** Make a copy of all components of the given trigger step. This has
237 ** the effect of copying all Expr.token.z values into memory obtained
238 ** from sqliteMalloc(). As initially created, the Expr.token.z values
239 ** all point to the input string that was fed to the parser. But that
240 ** string is ephemeral - it will go away as soon as the sqlite_exec()
241 ** call that started the parser exits. This routine makes a persistent
242 ** copy of all the Expr.token.z strings so that the TriggerStep structure
243 ** will be valid even after the sqlite_exec() call returns.
244 */
sqlitePersistTriggerStep(TriggerStep * p)245 static void sqlitePersistTriggerStep(TriggerStep *p){
246 if( p->target.z ){
247 p->target.z = sqliteStrNDup(p->target.z, p->target.n);
248 p->target.dyn = 1;
249 }
250 if( p->pSelect ){
251 Select *pNew = sqliteSelectDup(p->pSelect);
252 sqliteSelectDelete(p->pSelect);
253 p->pSelect = pNew;
254 }
255 if( p->pWhere ){
256 Expr *pNew = sqliteExprDup(p->pWhere);
257 sqliteExprDelete(p->pWhere);
258 p->pWhere = pNew;
259 }
260 if( p->pExprList ){
261 ExprList *pNew = sqliteExprListDup(p->pExprList);
262 sqliteExprListDelete(p->pExprList);
263 p->pExprList = pNew;
264 }
265 if( p->pIdList ){
266 IdList *pNew = sqliteIdListDup(p->pIdList);
267 sqliteIdListDelete(p->pIdList);
268 p->pIdList = pNew;
269 }
270 }
271
272 /*
273 ** Turn a SELECT statement (that the pSelect parameter points to) into
274 ** a trigger step. Return a pointer to a TriggerStep structure.
275 **
276 ** The parser calls this routine when it finds a SELECT statement in
277 ** body of a TRIGGER.
278 */
sqliteTriggerSelectStep(Select * pSelect)279 TriggerStep *sqliteTriggerSelectStep(Select *pSelect){
280 TriggerStep *pTriggerStep = sqliteMalloc(sizeof(TriggerStep));
281 if( pTriggerStep==0 ) return 0;
282
283 pTriggerStep->op = TK_SELECT;
284 pTriggerStep->pSelect = pSelect;
285 pTriggerStep->orconf = OE_Default;
286 sqlitePersistTriggerStep(pTriggerStep);
287
288 return pTriggerStep;
289 }
290
291 /*
292 ** Build a trigger step out of an INSERT statement. Return a pointer
293 ** to the new trigger step.
294 **
295 ** The parser calls this routine when it sees an INSERT inside the
296 ** body of a trigger.
297 */
sqliteTriggerInsertStep(Token * pTableName,IdList * pColumn,ExprList * pEList,Select * pSelect,int orconf)298 TriggerStep *sqliteTriggerInsertStep(
299 Token *pTableName, /* Name of the table into which we insert */
300 IdList *pColumn, /* List of columns in pTableName to insert into */
301 ExprList *pEList, /* The VALUE clause: a list of values to be inserted */
302 Select *pSelect, /* A SELECT statement that supplies values */
303 int orconf /* The conflict algorithm (OE_Abort, OE_Replace, etc.) */
304 ){
305 TriggerStep *pTriggerStep = sqliteMalloc(sizeof(TriggerStep));
306 if( pTriggerStep==0 ) return 0;
307
308 assert(pEList == 0 || pSelect == 0);
309 assert(pEList != 0 || pSelect != 0);
310
311 pTriggerStep->op = TK_INSERT;
312 pTriggerStep->pSelect = pSelect;
313 pTriggerStep->target = *pTableName;
314 pTriggerStep->pIdList = pColumn;
315 pTriggerStep->pExprList = pEList;
316 pTriggerStep->orconf = orconf;
317 sqlitePersistTriggerStep(pTriggerStep);
318
319 return pTriggerStep;
320 }
321
322 /*
323 ** Construct a trigger step that implements an UPDATE statement and return
324 ** a pointer to that trigger step. The parser calls this routine when it
325 ** sees an UPDATE statement inside the body of a CREATE TRIGGER.
326 */
sqliteTriggerUpdateStep(Token * pTableName,ExprList * pEList,Expr * pWhere,int orconf)327 TriggerStep *sqliteTriggerUpdateStep(
328 Token *pTableName, /* Name of the table to be updated */
329 ExprList *pEList, /* The SET clause: list of column and new values */
330 Expr *pWhere, /* The WHERE clause */
331 int orconf /* The conflict algorithm. (OE_Abort, OE_Ignore, etc) */
332 ){
333 TriggerStep *pTriggerStep = sqliteMalloc(sizeof(TriggerStep));
334 if( pTriggerStep==0 ) return 0;
335
336 pTriggerStep->op = TK_UPDATE;
337 pTriggerStep->target = *pTableName;
338 pTriggerStep->pExprList = pEList;
339 pTriggerStep->pWhere = pWhere;
340 pTriggerStep->orconf = orconf;
341 sqlitePersistTriggerStep(pTriggerStep);
342
343 return pTriggerStep;
344 }
345
346 /*
347 ** Construct a trigger step that implements a DELETE statement and return
348 ** a pointer to that trigger step. The parser calls this routine when it
349 ** sees a DELETE statement inside the body of a CREATE TRIGGER.
350 */
sqliteTriggerDeleteStep(Token * pTableName,Expr * pWhere)351 TriggerStep *sqliteTriggerDeleteStep(Token *pTableName, Expr *pWhere){
352 TriggerStep *pTriggerStep = sqliteMalloc(sizeof(TriggerStep));
353 if( pTriggerStep==0 ) return 0;
354
355 pTriggerStep->op = TK_DELETE;
356 pTriggerStep->target = *pTableName;
357 pTriggerStep->pWhere = pWhere;
358 pTriggerStep->orconf = OE_Default;
359 sqlitePersistTriggerStep(pTriggerStep);
360
361 return pTriggerStep;
362 }
363
364 /*
365 ** Recursively delete a Trigger structure
366 */
sqliteDeleteTrigger(Trigger * pTrigger)367 void sqliteDeleteTrigger(Trigger *pTrigger){
368 if( pTrigger==0 ) return;
369 sqliteDeleteTriggerStep(pTrigger->step_list);
370 sqliteFree(pTrigger->name);
371 sqliteFree(pTrigger->table);
372 sqliteExprDelete(pTrigger->pWhen);
373 sqliteIdListDelete(pTrigger->pColumns);
374 if( pTrigger->nameToken.dyn ) sqliteFree((char*)pTrigger->nameToken.z);
375 sqliteFree(pTrigger);
376 }
377
378 /*
379 * This function is called to drop a trigger from the database schema.
380 *
381 * This may be called directly from the parser and therefore identifies
382 * the trigger by name. The sqliteDropTriggerPtr() routine does the
383 * same job as this routine except it take a spointer to the trigger
384 * instead of the trigger name.
385 *
386 * Note that this function does not delete the trigger entirely. Instead it
387 * removes it from the internal schema and places it in the trigDrop hash
388 * table. This is so that the trigger can be restored into the database schema
389 * if the transaction is rolled back.
390 */
sqliteDropTrigger(Parse * pParse,SrcList * pName)391 void sqliteDropTrigger(Parse *pParse, SrcList *pName){
392 Trigger *pTrigger;
393 int i;
394 const char *zDb;
395 const char *zName;
396 int nName;
397 sqlite *db = pParse->db;
398
399 if( sqlite_malloc_failed ) goto drop_trigger_cleanup;
400 assert( pName->nSrc==1 );
401 zDb = pName->a[0].zDatabase;
402 zName = pName->a[0].zName;
403 nName = strlen(zName);
404 for(i=0; i<db->nDb; i++){
405 int j = (i<2) ? i^1 : i; /* Search TEMP before MAIN */
406 if( zDb && sqliteStrICmp(db->aDb[j].zName, zDb) ) continue;
407 pTrigger = sqliteHashFind(&(db->aDb[j].trigHash), zName, nName+1);
408 if( pTrigger ) break;
409 }
410 if( !pTrigger ){
411 sqliteErrorMsg(pParse, "no such trigger: %S", pName, 0);
412 goto drop_trigger_cleanup;
413 }
414 sqliteDropTriggerPtr(pParse, pTrigger, 0);
415
416 drop_trigger_cleanup:
417 sqliteSrcListDelete(pName);
418 }
419
420 /*
421 ** Drop a trigger given a pointer to that trigger. If nested is false,
422 ** then also generate code to remove the trigger from the SQLITE_MASTER
423 ** table.
424 */
sqliteDropTriggerPtr(Parse * pParse,Trigger * pTrigger,int nested)425 void sqliteDropTriggerPtr(Parse *pParse, Trigger *pTrigger, int nested){
426 Table *pTable;
427 Vdbe *v;
428 sqlite *db = pParse->db;
429
430 assert( pTrigger->iDb<db->nDb );
431 if( pTrigger->iDb>=2 ){
432 sqliteErrorMsg(pParse, "triggers may not be removed from "
433 "auxiliary database %s", db->aDb[pTrigger->iDb].zName);
434 return;
435 }
436 pTable = sqliteFindTable(db, pTrigger->table,db->aDb[pTrigger->iTabDb].zName);
437 assert(pTable);
438 assert( pTable->iDb==pTrigger->iDb || pTrigger->iDb==1 );
439 #ifndef SQLITE_OMIT_AUTHORIZATION
440 {
441 int code = SQLITE_DROP_TRIGGER;
442 const char *zDb = db->aDb[pTrigger->iDb].zName;
443 const char *zTab = SCHEMA_TABLE(pTrigger->iDb);
444 if( pTrigger->iDb ) code = SQLITE_DROP_TEMP_TRIGGER;
445 if( sqliteAuthCheck(pParse, code, pTrigger->name, pTable->zName, zDb) ||
446 sqliteAuthCheck(pParse, SQLITE_DELETE, zTab, 0, zDb) ){
447 return;
448 }
449 }
450 #endif
451
452 /* Generate code to destroy the database record of the trigger.
453 */
454 if( pTable!=0 && !nested && (v = sqliteGetVdbe(pParse))!=0 ){
455 int base;
456 static VdbeOpList dropTrigger[] = {
457 { OP_Rewind, 0, ADDR(9), 0},
458 { OP_String, 0, 0, 0}, /* 1 */
459 { OP_Column, 0, 1, 0},
460 { OP_Ne, 0, ADDR(8), 0},
461 { OP_String, 0, 0, "trigger"},
462 { OP_Column, 0, 0, 0},
463 { OP_Ne, 0, ADDR(8), 0},
464 { OP_Delete, 0, 0, 0},
465 { OP_Next, 0, ADDR(1), 0}, /* 8 */
466 };
467
468 sqliteBeginWriteOperation(pParse, 0, 0);
469 sqliteOpenMasterTable(v, pTrigger->iDb);
470 base = sqliteVdbeAddOpList(v, ArraySize(dropTrigger), dropTrigger);
471 sqliteVdbeChangeP3(v, base+1, pTrigger->name, 0);
472 if( pTrigger->iDb==0 ){
473 sqliteChangeCookie(db, v);
474 }
475 sqliteVdbeAddOp(v, OP_Close, 0, 0);
476 sqliteEndWriteOperation(pParse);
477 }
478
479 /*
480 * If this is not an "explain", then delete the trigger structure.
481 */
482 if( !pParse->explain ){
483 const char *zName = pTrigger->name;
484 int nName = strlen(zName);
485 if( pTable->pTrigger == pTrigger ){
486 pTable->pTrigger = pTrigger->pNext;
487 }else{
488 Trigger *cc = pTable->pTrigger;
489 while( cc ){
490 if( cc->pNext == pTrigger ){
491 cc->pNext = cc->pNext->pNext;
492 break;
493 }
494 cc = cc->pNext;
495 }
496 assert(cc);
497 }
498 sqliteHashInsert(&(db->aDb[pTrigger->iDb].trigHash), zName, nName+1, 0);
499 sqliteDeleteTrigger(pTrigger);
500 }
501 }
502
503 /*
504 ** pEList is the SET clause of an UPDATE statement. Each entry
505 ** in pEList is of the format <id>=<expr>. If any of the entries
506 ** in pEList have an <id> which matches an identifier in pIdList,
507 ** then return TRUE. If pIdList==NULL, then it is considered a
508 ** wildcard that matches anything. Likewise if pEList==NULL then
509 ** it matches anything so always return true. Return false only
510 ** if there is no match.
511 */
checkColumnOverLap(IdList * pIdList,ExprList * pEList)512 static int checkColumnOverLap(IdList *pIdList, ExprList *pEList){
513 int e;
514 if( !pIdList || !pEList ) return 1;
515 for(e=0; e<pEList->nExpr; e++){
516 if( sqliteIdListIndex(pIdList, pEList->a[e].zName)>=0 ) return 1;
517 }
518 return 0;
519 }
520
521 /* A global variable that is TRUE if we should always set up temp tables for
522 * for triggers, even if there are no triggers to code. This is used to test
523 * how much overhead the triggers algorithm is causing.
524 *
525 * This flag can be set or cleared using the "trigger_overhead_test" pragma.
526 * The pragma is not documented since it is not really part of the interface
527 * to SQLite, just the test procedure.
528 */
529 int always_code_trigger_setup = 0;
530
531 /*
532 * Returns true if a trigger matching op, tr_tm and foreach that is NOT already
533 * on the Parse objects trigger-stack (to prevent recursive trigger firing) is
534 * found in the list specified as pTrigger.
535 */
sqliteTriggersExist(Parse * pParse,Trigger * pTrigger,int op,int tr_tm,int foreach,ExprList * pChanges)536 int sqliteTriggersExist(
537 Parse *pParse, /* Used to check for recursive triggers */
538 Trigger *pTrigger, /* A list of triggers associated with a table */
539 int op, /* one of TK_DELETE, TK_INSERT, TK_UPDATE */
540 int tr_tm, /* one of TK_BEFORE, TK_AFTER */
541 int foreach, /* one of TK_ROW or TK_STATEMENT */
542 ExprList *pChanges /* Columns that change in an UPDATE statement */
543 ){
544 Trigger * pTriggerCursor;
545
546 if( always_code_trigger_setup ){
547 return 1;
548 }
549
550 pTriggerCursor = pTrigger;
551 while( pTriggerCursor ){
552 if( pTriggerCursor->op == op &&
553 pTriggerCursor->tr_tm == tr_tm &&
554 pTriggerCursor->foreach == foreach &&
555 checkColumnOverLap(pTriggerCursor->pColumns, pChanges) ){
556 TriggerStack * ss;
557 ss = pParse->trigStack;
558 while( ss && ss->pTrigger != pTrigger ){
559 ss = ss->pNext;
560 }
561 if( !ss )return 1;
562 }
563 pTriggerCursor = pTriggerCursor->pNext;
564 }
565
566 return 0;
567 }
568
569 /*
570 ** Convert the pStep->target token into a SrcList and return a pointer
571 ** to that SrcList.
572 **
573 ** This routine adds a specific database name, if needed, to the target when
574 ** forming the SrcList. This prevents a trigger in one database from
575 ** referring to a target in another database. An exception is when the
576 ** trigger is in TEMP in which case it can refer to any other database it
577 ** wants.
578 */
targetSrcList(Parse * pParse,TriggerStep * pStep)579 static SrcList *targetSrcList(
580 Parse *pParse, /* The parsing context */
581 TriggerStep *pStep /* The trigger containing the target token */
582 ){
583 Token sDb; /* Dummy database name token */
584 int iDb; /* Index of the database to use */
585 SrcList *pSrc; /* SrcList to be returned */
586
587 iDb = pStep->pTrig->iDb;
588 if( iDb==0 || iDb>=2 ){
589 assert( iDb<pParse->db->nDb );
590 sDb.z = pParse->db->aDb[iDb].zName;
591 sDb.n = strlen(sDb.z);
592 pSrc = sqliteSrcListAppend(0, &sDb, &pStep->target);
593 } else {
594 pSrc = sqliteSrcListAppend(0, &pStep->target, 0);
595 }
596 return pSrc;
597 }
598
599 /*
600 ** Generate VDBE code for zero or more statements inside the body of a
601 ** trigger.
602 */
codeTriggerProgram(Parse * pParse,TriggerStep * pStepList,int orconfin)603 static int codeTriggerProgram(
604 Parse *pParse, /* The parser context */
605 TriggerStep *pStepList, /* List of statements inside the trigger body */
606 int orconfin /* Conflict algorithm. (OE_Abort, etc) */
607 ){
608 TriggerStep * pTriggerStep = pStepList;
609 int orconf;
610
611 while( pTriggerStep ){
612 int saveNTab = pParse->nTab;
613
614 orconf = (orconfin == OE_Default)?pTriggerStep->orconf:orconfin;
615 pParse->trigStack->orconf = orconf;
616 switch( pTriggerStep->op ){
617 case TK_SELECT: {
618 Select * ss = sqliteSelectDup(pTriggerStep->pSelect);
619 assert(ss);
620 assert(ss->pSrc);
621 sqliteSelect(pParse, ss, SRT_Discard, 0, 0, 0, 0);
622 sqliteSelectDelete(ss);
623 break;
624 }
625 case TK_UPDATE: {
626 SrcList *pSrc;
627 pSrc = targetSrcList(pParse, pTriggerStep);
628 sqliteVdbeAddOp(pParse->pVdbe, OP_ListPush, 0, 0);
629 sqliteUpdate(pParse, pSrc,
630 sqliteExprListDup(pTriggerStep->pExprList),
631 sqliteExprDup(pTriggerStep->pWhere), orconf);
632 sqliteVdbeAddOp(pParse->pVdbe, OP_ListPop, 0, 0);
633 break;
634 }
635 case TK_INSERT: {
636 SrcList *pSrc;
637 pSrc = targetSrcList(pParse, pTriggerStep);
638 sqliteInsert(pParse, pSrc,
639 sqliteExprListDup(pTriggerStep->pExprList),
640 sqliteSelectDup(pTriggerStep->pSelect),
641 sqliteIdListDup(pTriggerStep->pIdList), orconf);
642 break;
643 }
644 case TK_DELETE: {
645 SrcList *pSrc;
646 sqliteVdbeAddOp(pParse->pVdbe, OP_ListPush, 0, 0);
647 pSrc = targetSrcList(pParse, pTriggerStep);
648 sqliteDeleteFrom(pParse, pSrc, sqliteExprDup(pTriggerStep->pWhere));
649 sqliteVdbeAddOp(pParse->pVdbe, OP_ListPop, 0, 0);
650 break;
651 }
652 default:
653 assert(0);
654 }
655 pParse->nTab = saveNTab;
656 pTriggerStep = pTriggerStep->pNext;
657 }
658
659 return 0;
660 }
661
662 /*
663 ** This is called to code FOR EACH ROW triggers.
664 **
665 ** When the code that this function generates is executed, the following
666 ** must be true:
667 **
668 ** 1. No cursors may be open in the main database. (But newIdx and oldIdx
669 ** can be indices of cursors in temporary tables. See below.)
670 **
671 ** 2. If the triggers being coded are ON INSERT or ON UPDATE triggers, then
672 ** a temporary vdbe cursor (index newIdx) must be open and pointing at
673 ** a row containing values to be substituted for new.* expressions in the
674 ** trigger program(s).
675 **
676 ** 3. If the triggers being coded are ON DELETE or ON UPDATE triggers, then
677 ** a temporary vdbe cursor (index oldIdx) must be open and pointing at
678 ** a row containing values to be substituted for old.* expressions in the
679 ** trigger program(s).
680 **
681 */
sqliteCodeRowTrigger(Parse * pParse,int op,ExprList * pChanges,int tr_tm,Table * pTab,int newIdx,int oldIdx,int orconf,int ignoreJump)682 int sqliteCodeRowTrigger(
683 Parse *pParse, /* Parse context */
684 int op, /* One of TK_UPDATE, TK_INSERT, TK_DELETE */
685 ExprList *pChanges, /* Changes list for any UPDATE OF triggers */
686 int tr_tm, /* One of TK_BEFORE, TK_AFTER */
687 Table *pTab, /* The table to code triggers from */
688 int newIdx, /* The indice of the "new" row to access */
689 int oldIdx, /* The indice of the "old" row to access */
690 int orconf, /* ON CONFLICT policy */
691 int ignoreJump /* Instruction to jump to for RAISE(IGNORE) */
692 ){
693 Trigger * pTrigger;
694 TriggerStack * pTriggerStack;
695
696 assert(op == TK_UPDATE || op == TK_INSERT || op == TK_DELETE);
697 assert(tr_tm == TK_BEFORE || tr_tm == TK_AFTER );
698
699 assert(newIdx != -1 || oldIdx != -1);
700
701 pTrigger = pTab->pTrigger;
702 while( pTrigger ){
703 int fire_this = 0;
704
705 /* determine whether we should code this trigger */
706 if( pTrigger->op == op && pTrigger->tr_tm == tr_tm &&
707 pTrigger->foreach == TK_ROW ){
708 fire_this = 1;
709 pTriggerStack = pParse->trigStack;
710 while( pTriggerStack ){
711 if( pTriggerStack->pTrigger == pTrigger ){
712 fire_this = 0;
713 }
714 pTriggerStack = pTriggerStack->pNext;
715 }
716 if( op == TK_UPDATE && pTrigger->pColumns &&
717 !checkColumnOverLap(pTrigger->pColumns, pChanges) ){
718 fire_this = 0;
719 }
720 }
721
722 if( fire_this && (pTriggerStack = sqliteMalloc(sizeof(TriggerStack)))!=0 ){
723 int endTrigger;
724 SrcList dummyTablist;
725 Expr * whenExpr;
726 AuthContext sContext;
727
728 dummyTablist.nSrc = 0;
729
730 /* Push an entry on to the trigger stack */
731 pTriggerStack->pTrigger = pTrigger;
732 pTriggerStack->newIdx = newIdx;
733 pTriggerStack->oldIdx = oldIdx;
734 pTriggerStack->pTab = pTab;
735 pTriggerStack->pNext = pParse->trigStack;
736 pTriggerStack->ignoreJump = ignoreJump;
737 pParse->trigStack = pTriggerStack;
738 sqliteAuthContextPush(pParse, &sContext, pTrigger->name);
739
740 /* code the WHEN clause */
741 endTrigger = sqliteVdbeMakeLabel(pParse->pVdbe);
742 whenExpr = sqliteExprDup(pTrigger->pWhen);
743 if( sqliteExprResolveIds(pParse, &dummyTablist, 0, whenExpr) ){
744 pParse->trigStack = pParse->trigStack->pNext;
745 sqliteFree(pTriggerStack);
746 sqliteExprDelete(whenExpr);
747 return 1;
748 }
749 sqliteExprIfFalse(pParse, whenExpr, endTrigger, 1);
750 sqliteExprDelete(whenExpr);
751
752 sqliteVdbeAddOp(pParse->pVdbe, OP_ContextPush, 0, 0);
753 codeTriggerProgram(pParse, pTrigger->step_list, orconf);
754 sqliteVdbeAddOp(pParse->pVdbe, OP_ContextPop, 0, 0);
755
756 /* Pop the entry off the trigger stack */
757 pParse->trigStack = pParse->trigStack->pNext;
758 sqliteAuthContextPop(&sContext);
759 sqliteFree(pTriggerStack);
760
761 sqliteVdbeResolveLabel(pParse->pVdbe, endTrigger);
762 }
763 pTrigger = pTrigger->pNext;
764 }
765
766 return 0;
767 }
768