Annotation of embedaddon/php/ext/sqlite/libsqlite/src/trigger.c, revision 1.1.1.1
1.1 misho 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: }
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