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 : #ifndef SQLITE_OMIT_TRIGGER
16 : /*
17 : ** Delete a linked list of TriggerStep structures.
18 : */
19 0 : void sqlite3DeleteTriggerStep(TriggerStep *pTriggerStep){
20 0 : while( pTriggerStep ){
21 0 : TriggerStep * pTmp = pTriggerStep;
22 0 : pTriggerStep = pTriggerStep->pNext;
23 :
24 0 : if( pTmp->target.dyn ) sqliteFree((char*)pTmp->target.z);
25 0 : sqlite3ExprDelete(pTmp->pWhere);
26 0 : sqlite3ExprListDelete(pTmp->pExprList);
27 0 : sqlite3SelectDelete(pTmp->pSelect);
28 0 : sqlite3IdListDelete(pTmp->pIdList);
29 :
30 0 : sqliteFree(pTmp);
31 : }
32 0 : }
33 :
34 : /*
35 : ** This is called by the parser when it sees a CREATE TRIGGER statement
36 : ** up to the point of the BEGIN before the trigger actions. A Trigger
37 : ** structure is generated based on the information available and stored
38 : ** in pParse->pNewTrigger. After the trigger actions have been parsed, the
39 : ** sqlite3FinishTrigger() function is called to complete the trigger
40 : ** construction process.
41 : */
42 : void sqlite3BeginTrigger(
43 : Parse *pParse, /* The parse context of the CREATE TRIGGER statement */
44 : Token *pName1, /* The name of the trigger */
45 : Token *pName2, /* The name of the trigger */
46 : int tr_tm, /* One of TK_BEFORE, TK_AFTER, TK_INSTEAD */
47 : int op, /* One of TK_INSERT, TK_UPDATE, TK_DELETE */
48 : IdList *pColumns, /* column list if this is an UPDATE OF trigger */
49 : SrcList *pTableName,/* The name of the table/view the trigger applies to */
50 : Expr *pWhen, /* WHEN clause */
51 : int isTemp, /* True if the TEMPORARY keyword is present */
52 : int noErr /* Suppress errors if the trigger already exists */
53 0 : ){
54 0 : Trigger *pTrigger = 0;
55 : Table *pTab;
56 0 : char *zName = 0; /* Name of the trigger */
57 0 : sqlite3 *db = pParse->db;
58 : int iDb; /* The database to store the trigger in */
59 : Token *pName; /* The unqualified db name */
60 : DbFixer sFix;
61 : int iTabDb;
62 :
63 : assert( pName1!=0 ); /* pName1->z might be NULL, but not pName1 itself */
64 : assert( pName2!=0 );
65 0 : if( isTemp ){
66 : /* If TEMP was specified, then the trigger name may not be qualified. */
67 0 : if( pName2->n>0 ){
68 0 : sqlite3ErrorMsg(pParse, "temporary trigger may not have qualified name");
69 0 : goto trigger_cleanup;
70 : }
71 0 : iDb = 1;
72 0 : pName = pName1;
73 : }else{
74 : /* Figure out the db that the the trigger will be created in */
75 0 : iDb = sqlite3TwoPartName(pParse, pName1, pName2, &pName);
76 0 : if( iDb<0 ){
77 0 : goto trigger_cleanup;
78 : }
79 : }
80 :
81 : /* If the trigger name was unqualified, and the table is a temp table,
82 : ** then set iDb to 1 to create the trigger in the temporary database.
83 : ** If sqlite3SrcListLookup() returns 0, indicating the table does not
84 : ** exist, the error is caught by the block below.
85 : */
86 0 : if( !pTableName || sqlite3MallocFailed() ){
87 : goto trigger_cleanup;
88 : }
89 0 : pTab = sqlite3SrcListLookup(pParse, pTableName);
90 0 : if( pName2->n==0 && pTab && pTab->pSchema==db->aDb[1].pSchema ){
91 0 : iDb = 1;
92 : }
93 :
94 : /* Ensure the table name matches database name and that the table exists */
95 0 : if( sqlite3MallocFailed() ) goto trigger_cleanup;
96 : assert( pTableName->nSrc==1 );
97 0 : if( sqlite3FixInit(&sFix, pParse, iDb, "trigger", pName) &&
98 : sqlite3FixSrcList(&sFix, pTableName) ){
99 0 : goto trigger_cleanup;
100 : }
101 0 : pTab = sqlite3SrcListLookup(pParse, pTableName);
102 0 : if( !pTab ){
103 : /* The table does not exist. */
104 0 : goto trigger_cleanup;
105 : }
106 0 : if( IsVirtual(pTab) ){
107 0 : sqlite3ErrorMsg(pParse, "cannot create triggers on virtual tables");
108 0 : goto trigger_cleanup;
109 : }
110 :
111 : /* Check that the trigger name is not reserved and that no trigger of the
112 : ** specified name exists */
113 0 : zName = sqlite3NameFromToken(pName);
114 0 : if( !zName || SQLITE_OK!=sqlite3CheckObjectName(pParse, zName) ){
115 : goto trigger_cleanup;
116 : }
117 0 : if( sqlite3HashFind(&(db->aDb[iDb].pSchema->trigHash), zName,strlen(zName)) ){
118 0 : if( !noErr ){
119 0 : sqlite3ErrorMsg(pParse, "trigger %T already exists", pName);
120 : }
121 0 : goto trigger_cleanup;
122 : }
123 :
124 : /* Do not create a trigger on a system table */
125 0 : if( sqlite3StrNICmp(pTab->zName, "sqlite_", 7)==0 ){
126 0 : sqlite3ErrorMsg(pParse, "cannot create trigger on system table");
127 0 : pParse->nErr++;
128 0 : goto trigger_cleanup;
129 : }
130 :
131 : /* INSTEAD of triggers are only for views and views only support INSTEAD
132 : ** of triggers.
133 : */
134 0 : if( pTab->pSelect && tr_tm!=TK_INSTEAD ){
135 0 : sqlite3ErrorMsg(pParse, "cannot create %s trigger on view: %S",
136 : (tr_tm == TK_BEFORE)?"BEFORE":"AFTER", pTableName, 0);
137 0 : goto trigger_cleanup;
138 : }
139 0 : if( !pTab->pSelect && tr_tm==TK_INSTEAD ){
140 0 : sqlite3ErrorMsg(pParse, "cannot create INSTEAD OF"
141 : " trigger on table: %S", pTableName, 0);
142 0 : goto trigger_cleanup;
143 : }
144 0 : iTabDb = sqlite3SchemaToIndex(db, pTab->pSchema);
145 :
146 : #ifndef SQLITE_OMIT_AUTHORIZATION
147 : {
148 0 : int code = SQLITE_CREATE_TRIGGER;
149 0 : const char *zDb = db->aDb[iTabDb].zName;
150 0 : const char *zDbTrig = isTemp ? db->aDb[1].zName : zDb;
151 0 : if( iTabDb==1 || isTemp ) code = SQLITE_CREATE_TEMP_TRIGGER;
152 0 : if( sqlite3AuthCheck(pParse, code, zName, pTab->zName, zDbTrig) ){
153 0 : goto trigger_cleanup;
154 : }
155 0 : if( sqlite3AuthCheck(pParse, SQLITE_INSERT, SCHEMA_TABLE(iTabDb),0,zDb)){
156 0 : goto trigger_cleanup;
157 : }
158 : }
159 : #endif
160 :
161 : /* INSTEAD OF triggers can only appear on views and BEFORE triggers
162 : ** cannot appear on views. So we might as well translate every
163 : ** INSTEAD OF trigger into a BEFORE trigger. It simplifies code
164 : ** elsewhere.
165 : */
166 0 : if (tr_tm == TK_INSTEAD){
167 0 : tr_tm = TK_BEFORE;
168 : }
169 :
170 : /* Build the Trigger object */
171 0 : pTrigger = (Trigger*)sqliteMalloc(sizeof(Trigger));
172 0 : if( pTrigger==0 ) goto trigger_cleanup;
173 0 : pTrigger->name = zName;
174 0 : zName = 0;
175 0 : pTrigger->table = sqliteStrDup(pTableName->a[0].zName);
176 0 : pTrigger->pSchema = db->aDb[iDb].pSchema;
177 0 : pTrigger->pTabSchema = pTab->pSchema;
178 0 : pTrigger->op = op;
179 0 : pTrigger->tr_tm = tr_tm==TK_BEFORE ? TRIGGER_BEFORE : TRIGGER_AFTER;
180 0 : pTrigger->pWhen = sqlite3ExprDup(pWhen);
181 0 : pTrigger->pColumns = sqlite3IdListDup(pColumns);
182 0 : sqlite3TokenCopy(&pTrigger->nameToken,pName);
183 : assert( pParse->pNewTrigger==0 );
184 0 : pParse->pNewTrigger = pTrigger;
185 :
186 0 : trigger_cleanup:
187 0 : sqliteFree(zName);
188 0 : sqlite3SrcListDelete(pTableName);
189 0 : sqlite3IdListDelete(pColumns);
190 0 : sqlite3ExprDelete(pWhen);
191 0 : if( !pParse->pNewTrigger ){
192 0 : sqlite3DeleteTrigger(pTrigger);
193 : }else{
194 : assert( pParse->pNewTrigger==pTrigger );
195 : }
196 0 : }
197 :
198 : /*
199 : ** This routine is called after all of the trigger actions have been parsed
200 : ** in order to complete the process of building the trigger.
201 : */
202 : void sqlite3FinishTrigger(
203 : Parse *pParse, /* Parser context */
204 : TriggerStep *pStepList, /* The triggered program */
205 : Token *pAll /* Token that describes the complete CREATE TRIGGER */
206 0 : ){
207 0 : Trigger *pTrig = 0; /* The trigger whose construction is finishing up */
208 0 : sqlite3 *db = pParse->db; /* The database */
209 : DbFixer sFix;
210 : int iDb; /* Database containing the trigger */
211 :
212 0 : pTrig = pParse->pNewTrigger;
213 0 : pParse->pNewTrigger = 0;
214 0 : if( pParse->nErr || !pTrig ) goto triggerfinish_cleanup;
215 0 : iDb = sqlite3SchemaToIndex(pParse->db, pTrig->pSchema);
216 0 : pTrig->step_list = pStepList;
217 0 : while( pStepList ){
218 0 : pStepList->pTrig = pTrig;
219 0 : pStepList = pStepList->pNext;
220 : }
221 0 : if( sqlite3FixInit(&sFix, pParse, iDb, "trigger", &pTrig->nameToken)
222 : && sqlite3FixTriggerStep(&sFix, pTrig->step_list) ){
223 0 : goto triggerfinish_cleanup;
224 : }
225 :
226 : /* if we are not initializing, and this trigger is not on a TEMP table,
227 : ** build the sqlite_master entry
228 : */
229 0 : if( !db->init.busy ){
230 : static const VdbeOpList insertTrig[] = {
231 : { OP_NewRowid, 0, 0, 0 },
232 : { OP_String8, 0, 0, "trigger" },
233 : { OP_String8, 0, 0, 0 }, /* 2: trigger name */
234 : { OP_String8, 0, 0, 0 }, /* 3: table name */
235 : { OP_Integer, 0, 0, 0 },
236 : { OP_String8, 0, 0, "CREATE TRIGGER "},
237 : { OP_String8, 0, 0, 0 }, /* 6: SQL */
238 : { OP_Concat, 0, 0, 0 },
239 : { OP_MakeRecord, 5, 0, "aaada" },
240 : { OP_Insert, 0, 0, 0 },
241 : };
242 : int addr;
243 : Vdbe *v;
244 :
245 : /* Make an entry in the sqlite_master table */
246 0 : v = sqlite3GetVdbe(pParse);
247 0 : if( v==0 ) goto triggerfinish_cleanup;
248 0 : sqlite3BeginWriteOperation(pParse, 0, iDb);
249 0 : sqlite3OpenMasterTable(pParse, iDb);
250 0 : addr = sqlite3VdbeAddOpList(v, ArraySize(insertTrig), insertTrig);
251 0 : sqlite3VdbeChangeP3(v, addr+2, pTrig->name, 0);
252 0 : sqlite3VdbeChangeP3(v, addr+3, pTrig->table, 0);
253 0 : sqlite3VdbeChangeP3(v, addr+6, (char*)pAll->z, pAll->n);
254 0 : sqlite3ChangeCookie(db, v, iDb);
255 0 : sqlite3VdbeAddOp(v, OP_Close, 0, 0);
256 0 : sqlite3VdbeOp3(v, OP_ParseSchema, iDb, 0,
257 : sqlite3MPrintf("type='trigger' AND name='%q'", pTrig->name), P3_DYNAMIC);
258 : }
259 :
260 0 : if( db->init.busy ){
261 : int n;
262 : Table *pTab;
263 : Trigger *pDel;
264 0 : pDel = sqlite3HashInsert(&db->aDb[iDb].pSchema->trigHash,
265 : pTrig->name, strlen(pTrig->name), pTrig);
266 0 : if( pDel ){
267 : assert( sqlite3MallocFailed() && pDel==pTrig );
268 0 : goto triggerfinish_cleanup;
269 : }
270 0 : n = strlen(pTrig->table) + 1;
271 0 : pTab = sqlite3HashFind(&pTrig->pTabSchema->tblHash, pTrig->table, n);
272 : assert( pTab!=0 );
273 0 : pTrig->pNext = pTab->pTrigger;
274 0 : pTab->pTrigger = pTrig;
275 0 : pTrig = 0;
276 : }
277 :
278 0 : triggerfinish_cleanup:
279 0 : sqlite3DeleteTrigger(pTrig);
280 : assert( !pParse->pNewTrigger );
281 0 : sqlite3DeleteTriggerStep(pStepList);
282 0 : }
283 :
284 : /*
285 : ** Make a copy of all components of the given trigger step. This has
286 : ** the effect of copying all Expr.token.z values into memory obtained
287 : ** from sqliteMalloc(). As initially created, the Expr.token.z values
288 : ** all point to the input string that was fed to the parser. But that
289 : ** string is ephemeral - it will go away as soon as the sqlite3_exec()
290 : ** call that started the parser exits. This routine makes a persistent
291 : ** copy of all the Expr.token.z strings so that the TriggerStep structure
292 : ** will be valid even after the sqlite3_exec() call returns.
293 : */
294 0 : static void sqlitePersistTriggerStep(TriggerStep *p){
295 0 : if( p->target.z ){
296 0 : p->target.z = (u8*)sqliteStrNDup((char*)p->target.z, p->target.n);
297 0 : p->target.dyn = 1;
298 : }
299 0 : if( p->pSelect ){
300 0 : Select *pNew = sqlite3SelectDup(p->pSelect);
301 0 : sqlite3SelectDelete(p->pSelect);
302 0 : p->pSelect = pNew;
303 : }
304 0 : if( p->pWhere ){
305 0 : Expr *pNew = sqlite3ExprDup(p->pWhere);
306 0 : sqlite3ExprDelete(p->pWhere);
307 0 : p->pWhere = pNew;
308 : }
309 0 : if( p->pExprList ){
310 0 : ExprList *pNew = sqlite3ExprListDup(p->pExprList);
311 0 : sqlite3ExprListDelete(p->pExprList);
312 0 : p->pExprList = pNew;
313 : }
314 0 : if( p->pIdList ){
315 0 : IdList *pNew = sqlite3IdListDup(p->pIdList);
316 0 : sqlite3IdListDelete(p->pIdList);
317 0 : p->pIdList = pNew;
318 : }
319 0 : }
320 :
321 : /*
322 : ** Turn a SELECT statement (that the pSelect parameter points to) into
323 : ** a trigger step. Return a pointer to a TriggerStep structure.
324 : **
325 : ** The parser calls this routine when it finds a SELECT statement in
326 : ** body of a TRIGGER.
327 : */
328 0 : TriggerStep *sqlite3TriggerSelectStep(Select *pSelect){
329 0 : TriggerStep *pTriggerStep = sqliteMalloc(sizeof(TriggerStep));
330 0 : if( pTriggerStep==0 ) {
331 0 : sqlite3SelectDelete(pSelect);
332 0 : return 0;
333 : }
334 :
335 0 : pTriggerStep->op = TK_SELECT;
336 0 : pTriggerStep->pSelect = pSelect;
337 0 : pTriggerStep->orconf = OE_Default;
338 0 : sqlitePersistTriggerStep(pTriggerStep);
339 :
340 0 : return pTriggerStep;
341 : }
342 :
343 : /*
344 : ** Build a trigger step out of an INSERT statement. Return a pointer
345 : ** to the new trigger step.
346 : **
347 : ** The parser calls this routine when it sees an INSERT inside the
348 : ** body of a trigger.
349 : */
350 : TriggerStep *sqlite3TriggerInsertStep(
351 : Token *pTableName, /* Name of the table into which we insert */
352 : IdList *pColumn, /* List of columns in pTableName to insert into */
353 : ExprList *pEList, /* The VALUE clause: a list of values to be inserted */
354 : Select *pSelect, /* A SELECT statement that supplies values */
355 : int orconf /* The conflict algorithm (OE_Abort, OE_Replace, etc.) */
356 0 : ){
357 0 : TriggerStep *pTriggerStep = sqliteMalloc(sizeof(TriggerStep));
358 :
359 : assert(pEList == 0 || pSelect == 0);
360 : assert(pEList != 0 || pSelect != 0);
361 :
362 0 : if( pTriggerStep ){
363 0 : pTriggerStep->op = TK_INSERT;
364 0 : pTriggerStep->pSelect = pSelect;
365 0 : pTriggerStep->target = *pTableName;
366 0 : pTriggerStep->pIdList = pColumn;
367 0 : pTriggerStep->pExprList = pEList;
368 0 : pTriggerStep->orconf = orconf;
369 0 : sqlitePersistTriggerStep(pTriggerStep);
370 : }else{
371 0 : sqlite3IdListDelete(pColumn);
372 0 : sqlite3ExprListDelete(pEList);
373 0 : sqlite3SelectDup(pSelect);
374 : }
375 :
376 0 : return pTriggerStep;
377 : }
378 :
379 : /*
380 : ** Construct a trigger step that implements an UPDATE statement and return
381 : ** a pointer to that trigger step. The parser calls this routine when it
382 : ** sees an UPDATE statement inside the body of a CREATE TRIGGER.
383 : */
384 : TriggerStep *sqlite3TriggerUpdateStep(
385 : Token *pTableName, /* Name of the table to be updated */
386 : ExprList *pEList, /* The SET clause: list of column and new values */
387 : Expr *pWhere, /* The WHERE clause */
388 : int orconf /* The conflict algorithm. (OE_Abort, OE_Ignore, etc) */
389 0 : ){
390 0 : TriggerStep *pTriggerStep = sqliteMalloc(sizeof(TriggerStep));
391 0 : if( pTriggerStep==0 ){
392 0 : sqlite3ExprListDelete(pEList);
393 0 : sqlite3ExprDelete(pWhere);
394 0 : return 0;
395 : }
396 :
397 0 : pTriggerStep->op = TK_UPDATE;
398 0 : pTriggerStep->target = *pTableName;
399 0 : pTriggerStep->pExprList = pEList;
400 0 : pTriggerStep->pWhere = pWhere;
401 0 : pTriggerStep->orconf = orconf;
402 0 : sqlitePersistTriggerStep(pTriggerStep);
403 :
404 0 : return pTriggerStep;
405 : }
406 :
407 : /*
408 : ** Construct a trigger step that implements a DELETE statement and return
409 : ** a pointer to that trigger step. The parser calls this routine when it
410 : ** sees a DELETE statement inside the body of a CREATE TRIGGER.
411 : */
412 0 : TriggerStep *sqlite3TriggerDeleteStep(Token *pTableName, Expr *pWhere){
413 0 : TriggerStep *pTriggerStep = sqliteMalloc(sizeof(TriggerStep));
414 0 : if( pTriggerStep==0 ){
415 0 : sqlite3ExprDelete(pWhere);
416 0 : return 0;
417 : }
418 :
419 0 : pTriggerStep->op = TK_DELETE;
420 0 : pTriggerStep->target = *pTableName;
421 0 : pTriggerStep->pWhere = pWhere;
422 0 : pTriggerStep->orconf = OE_Default;
423 0 : sqlitePersistTriggerStep(pTriggerStep);
424 :
425 0 : return pTriggerStep;
426 : }
427 :
428 : /*
429 : ** Recursively delete a Trigger structure
430 : */
431 1036 : void sqlite3DeleteTrigger(Trigger *pTrigger){
432 1036 : if( pTrigger==0 ) return;
433 0 : sqlite3DeleteTriggerStep(pTrigger->step_list);
434 0 : sqliteFree(pTrigger->name);
435 0 : sqliteFree(pTrigger->table);
436 0 : sqlite3ExprDelete(pTrigger->pWhen);
437 0 : sqlite3IdListDelete(pTrigger->pColumns);
438 0 : if( pTrigger->nameToken.dyn ) sqliteFree((char*)pTrigger->nameToken.z);
439 0 : sqliteFree(pTrigger);
440 : }
441 :
442 : /*
443 : ** This function is called to drop a trigger from the database schema.
444 : **
445 : ** This may be called directly from the parser and therefore identifies
446 : ** the trigger by name. The sqlite3DropTriggerPtr() routine does the
447 : ** same job as this routine except it takes a pointer to the trigger
448 : ** instead of the trigger name.
449 : **/
450 0 : void sqlite3DropTrigger(Parse *pParse, SrcList *pName, int noErr){
451 0 : Trigger *pTrigger = 0;
452 : int i;
453 : const char *zDb;
454 : const char *zName;
455 : int nName;
456 0 : sqlite3 *db = pParse->db;
457 :
458 0 : if( sqlite3MallocFailed() ) goto drop_trigger_cleanup;
459 0 : if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
460 0 : goto drop_trigger_cleanup;
461 : }
462 :
463 : assert( pName->nSrc==1 );
464 0 : zDb = pName->a[0].zDatabase;
465 0 : zName = pName->a[0].zName;
466 0 : nName = strlen(zName);
467 0 : for(i=OMIT_TEMPDB; i<db->nDb; i++){
468 0 : int j = (i<2) ? i^1 : i; /* Search TEMP before MAIN */
469 0 : if( zDb && sqlite3StrICmp(db->aDb[j].zName, zDb) ) continue;
470 0 : pTrigger = sqlite3HashFind(&(db->aDb[j].pSchema->trigHash), zName, nName);
471 0 : if( pTrigger ) break;
472 : }
473 0 : if( !pTrigger ){
474 0 : if( !noErr ){
475 0 : sqlite3ErrorMsg(pParse, "no such trigger: %S", pName, 0);
476 : }
477 0 : goto drop_trigger_cleanup;
478 : }
479 0 : sqlite3DropTriggerPtr(pParse, pTrigger);
480 :
481 0 : drop_trigger_cleanup:
482 0 : sqlite3SrcListDelete(pName);
483 0 : }
484 :
485 : /*
486 : ** Return a pointer to the Table structure for the table that a trigger
487 : ** is set on.
488 : */
489 0 : static Table *tableOfTrigger(Trigger *pTrigger){
490 0 : int n = strlen(pTrigger->table) + 1;
491 0 : return sqlite3HashFind(&pTrigger->pTabSchema->tblHash, pTrigger->table, n);
492 : }
493 :
494 :
495 : /*
496 : ** Drop a trigger given a pointer to that trigger.
497 : */
498 0 : void sqlite3DropTriggerPtr(Parse *pParse, Trigger *pTrigger){
499 : Table *pTable;
500 : Vdbe *v;
501 0 : sqlite3 *db = pParse->db;
502 : int iDb;
503 :
504 0 : iDb = sqlite3SchemaToIndex(pParse->db, pTrigger->pSchema);
505 : assert( iDb>=0 && iDb<db->nDb );
506 0 : pTable = tableOfTrigger(pTrigger);
507 : assert( pTable );
508 : assert( pTable->pSchema==pTrigger->pSchema || iDb==1 );
509 : #ifndef SQLITE_OMIT_AUTHORIZATION
510 : {
511 0 : int code = SQLITE_DROP_TRIGGER;
512 0 : const char *zDb = db->aDb[iDb].zName;
513 0 : const char *zTab = SCHEMA_TABLE(iDb);
514 0 : if( iDb==1 ) code = SQLITE_DROP_TEMP_TRIGGER;
515 0 : if( sqlite3AuthCheck(pParse, code, pTrigger->name, pTable->zName, zDb) ||
516 : sqlite3AuthCheck(pParse, SQLITE_DELETE, zTab, 0, zDb) ){
517 0 : return;
518 : }
519 : }
520 : #endif
521 :
522 : /* Generate code to destroy the database record of the trigger.
523 : */
524 : assert( pTable!=0 );
525 0 : if( (v = sqlite3GetVdbe(pParse))!=0 ){
526 : int base;
527 : static const VdbeOpList dropTrigger[] = {
528 : { OP_Rewind, 0, ADDR(9), 0},
529 : { OP_String8, 0, 0, 0}, /* 1 */
530 : { OP_Column, 0, 1, 0},
531 : { OP_Ne, 0, ADDR(8), 0},
532 : { OP_String8, 0, 0, "trigger"},
533 : { OP_Column, 0, 0, 0},
534 : { OP_Ne, 0, ADDR(8), 0},
535 : { OP_Delete, 0, 0, 0},
536 : { OP_Next, 0, ADDR(1), 0}, /* 8 */
537 : };
538 :
539 0 : sqlite3BeginWriteOperation(pParse, 0, iDb);
540 0 : sqlite3OpenMasterTable(pParse, iDb);
541 0 : base = sqlite3VdbeAddOpList(v, ArraySize(dropTrigger), dropTrigger);
542 0 : sqlite3VdbeChangeP3(v, base+1, pTrigger->name, 0);
543 0 : sqlite3ChangeCookie(db, v, iDb);
544 0 : sqlite3VdbeAddOp(v, OP_Close, 0, 0);
545 0 : sqlite3VdbeOp3(v, OP_DropTrigger, iDb, 0, pTrigger->name, 0);
546 : }
547 : }
548 :
549 : /*
550 : ** Remove a trigger from the hash tables of the sqlite* pointer.
551 : */
552 0 : void sqlite3UnlinkAndDeleteTrigger(sqlite3 *db, int iDb, const char *zName){
553 : Trigger *pTrigger;
554 0 : int nName = strlen(zName);
555 0 : pTrigger = sqlite3HashInsert(&(db->aDb[iDb].pSchema->trigHash),
556 : zName, nName, 0);
557 0 : if( pTrigger ){
558 0 : Table *pTable = tableOfTrigger(pTrigger);
559 : assert( pTable!=0 );
560 0 : if( pTable->pTrigger == pTrigger ){
561 0 : pTable->pTrigger = pTrigger->pNext;
562 : }else{
563 0 : Trigger *cc = pTable->pTrigger;
564 0 : while( cc ){
565 0 : if( cc->pNext == pTrigger ){
566 0 : cc->pNext = cc->pNext->pNext;
567 0 : break;
568 : }
569 0 : cc = cc->pNext;
570 : }
571 : assert(cc);
572 : }
573 0 : sqlite3DeleteTrigger(pTrigger);
574 0 : db->flags |= SQLITE_InternChanges;
575 : }
576 0 : }
577 :
578 : /*
579 : ** pEList is the SET clause of an UPDATE statement. Each entry
580 : ** in pEList is of the format <id>=<expr>. If any of the entries
581 : ** in pEList have an <id> which matches an identifier in pIdList,
582 : ** then return TRUE. If pIdList==NULL, then it is considered a
583 : ** wildcard that matches anything. Likewise if pEList==NULL then
584 : ** it matches anything so always return true. Return false only
585 : ** if there is no match.
586 : */
587 0 : static int checkColumnOverLap(IdList *pIdList, ExprList *pEList){
588 : int e;
589 0 : if( !pIdList || !pEList ) return 1;
590 0 : for(e=0; e<pEList->nExpr; e++){
591 0 : if( sqlite3IdListIndex(pIdList, pEList->a[e].zName)>=0 ) return 1;
592 : }
593 0 : return 0;
594 : }
595 :
596 : /*
597 : ** Return a bit vector to indicate what kind of triggers exist for operation
598 : ** "op" on table pTab. If pChanges is not NULL then it is a list of columns
599 : ** that are being updated. Triggers only match if the ON clause of the
600 : ** trigger definition overlaps the set of columns being updated.
601 : **
602 : ** The returned bit vector is some combination of TRIGGER_BEFORE and
603 : ** TRIGGER_AFTER.
604 : */
605 : int sqlite3TriggersExist(
606 : Parse *pParse, /* Used to check for recursive triggers */
607 : Table *pTab, /* The table the contains the triggers */
608 : int op, /* one of TK_DELETE, TK_INSERT, TK_UPDATE */
609 : ExprList *pChanges /* Columns that change in an UPDATE statement */
610 228 : ){
611 : Trigger *pTrigger;
612 228 : int mask = 0;
613 :
614 228 : pTrigger = IsVirtual(pTab) ? 0 : pTab->pTrigger;
615 456 : while( pTrigger ){
616 0 : if( pTrigger->op==op && checkColumnOverLap(pTrigger->pColumns, pChanges) ){
617 0 : mask |= pTrigger->tr_tm;
618 : }
619 0 : pTrigger = pTrigger->pNext;
620 : }
621 228 : return mask;
622 : }
623 :
624 : /*
625 : ** Convert the pStep->target token into a SrcList and return a pointer
626 : ** to that SrcList.
627 : **
628 : ** This routine adds a specific database name, if needed, to the target when
629 : ** forming the SrcList. This prevents a trigger in one database from
630 : ** referring to a target in another database. An exception is when the
631 : ** trigger is in TEMP in which case it can refer to any other database it
632 : ** wants.
633 : */
634 : static SrcList *targetSrcList(
635 : Parse *pParse, /* The parsing context */
636 : TriggerStep *pStep /* The trigger containing the target token */
637 0 : ){
638 : Token sDb; /* Dummy database name token */
639 : int iDb; /* Index of the database to use */
640 : SrcList *pSrc; /* SrcList to be returned */
641 :
642 0 : iDb = sqlite3SchemaToIndex(pParse->db, pStep->pTrig->pSchema);
643 0 : if( iDb==0 || iDb>=2 ){
644 : assert( iDb<pParse->db->nDb );
645 0 : sDb.z = (u8*)pParse->db->aDb[iDb].zName;
646 0 : sDb.n = strlen((char*)sDb.z);
647 0 : pSrc = sqlite3SrcListAppend(0, &sDb, &pStep->target);
648 : } else {
649 0 : pSrc = sqlite3SrcListAppend(0, &pStep->target, 0);
650 : }
651 0 : return pSrc;
652 : }
653 :
654 : /*
655 : ** Generate VDBE code for zero or more statements inside the body of a
656 : ** trigger.
657 : */
658 : static int codeTriggerProgram(
659 : Parse *pParse, /* The parser context */
660 : TriggerStep *pStepList, /* List of statements inside the trigger body */
661 : int orconfin /* Conflict algorithm. (OE_Abort, etc) */
662 0 : ){
663 0 : TriggerStep * pTriggerStep = pStepList;
664 : int orconf;
665 0 : Vdbe *v = pParse->pVdbe;
666 :
667 : assert( pTriggerStep!=0 );
668 : assert( v!=0 );
669 0 : sqlite3VdbeAddOp(v, OP_ContextPush, 0, 0);
670 : VdbeComment((v, "# begin trigger %s", pStepList->pTrig->name));
671 0 : while( pTriggerStep ){
672 0 : orconf = (orconfin == OE_Default)?pTriggerStep->orconf:orconfin;
673 0 : pParse->trigStack->orconf = orconf;
674 0 : switch( pTriggerStep->op ){
675 : case TK_SELECT: {
676 0 : Select *ss = sqlite3SelectDup(pTriggerStep->pSelect);
677 0 : if( ss ){
678 0 : sqlite3SelectResolve(pParse, ss, 0);
679 0 : sqlite3Select(pParse, ss, SRT_Discard, 0, 0, 0, 0, 0);
680 0 : sqlite3SelectDelete(ss);
681 : }
682 0 : break;
683 : }
684 : case TK_UPDATE: {
685 : SrcList *pSrc;
686 0 : pSrc = targetSrcList(pParse, pTriggerStep);
687 0 : sqlite3VdbeAddOp(v, OP_ResetCount, 0, 0);
688 0 : sqlite3Update(pParse, pSrc,
689 : sqlite3ExprListDup(pTriggerStep->pExprList),
690 : sqlite3ExprDup(pTriggerStep->pWhere), orconf);
691 0 : sqlite3VdbeAddOp(v, OP_ResetCount, 1, 0);
692 0 : break;
693 : }
694 : case TK_INSERT: {
695 : SrcList *pSrc;
696 0 : pSrc = targetSrcList(pParse, pTriggerStep);
697 0 : sqlite3VdbeAddOp(v, OP_ResetCount, 0, 0);
698 0 : sqlite3Insert(pParse, pSrc,
699 : sqlite3ExprListDup(pTriggerStep->pExprList),
700 : sqlite3SelectDup(pTriggerStep->pSelect),
701 : sqlite3IdListDup(pTriggerStep->pIdList), orconf);
702 0 : sqlite3VdbeAddOp(v, OP_ResetCount, 1, 0);
703 0 : break;
704 : }
705 : case TK_DELETE: {
706 : SrcList *pSrc;
707 0 : sqlite3VdbeAddOp(v, OP_ResetCount, 0, 0);
708 0 : pSrc = targetSrcList(pParse, pTriggerStep);
709 0 : sqlite3DeleteFrom(pParse, pSrc, sqlite3ExprDup(pTriggerStep->pWhere));
710 0 : sqlite3VdbeAddOp(v, OP_ResetCount, 1, 0);
711 : break;
712 : }
713 : default:
714 : assert(0);
715 : }
716 0 : pTriggerStep = pTriggerStep->pNext;
717 : }
718 0 : sqlite3VdbeAddOp(v, OP_ContextPop, 0, 0);
719 : VdbeComment((v, "# end trigger %s", pStepList->pTrig->name));
720 :
721 0 : return 0;
722 : }
723 :
724 : /*
725 : ** This is called to code FOR EACH ROW triggers.
726 : **
727 : ** When the code that this function generates is executed, the following
728 : ** must be true:
729 : **
730 : ** 1. No cursors may be open in the main database. (But newIdx and oldIdx
731 : ** can be indices of cursors in temporary tables. See below.)
732 : **
733 : ** 2. If the triggers being coded are ON INSERT or ON UPDATE triggers, then
734 : ** a temporary vdbe cursor (index newIdx) must be open and pointing at
735 : ** a row containing values to be substituted for new.* expressions in the
736 : ** trigger program(s).
737 : **
738 : ** 3. If the triggers being coded are ON DELETE or ON UPDATE triggers, then
739 : ** a temporary vdbe cursor (index oldIdx) must be open and pointing at
740 : ** a row containing values to be substituted for old.* expressions in the
741 : ** trigger program(s).
742 : **
743 : */
744 : int sqlite3CodeRowTrigger(
745 : Parse *pParse, /* Parse context */
746 : int op, /* One of TK_UPDATE, TK_INSERT, TK_DELETE */
747 : ExprList *pChanges, /* Changes list for any UPDATE OF triggers */
748 : int tr_tm, /* One of TRIGGER_BEFORE, TRIGGER_AFTER */
749 : Table *pTab, /* The table to code triggers from */
750 : int newIdx, /* The indice of the "new" row to access */
751 : int oldIdx, /* The indice of the "old" row to access */
752 : int orconf, /* ON CONFLICT policy */
753 : int ignoreJump /* Instruction to jump to for RAISE(IGNORE) */
754 0 : ){
755 : Trigger *p;
756 : TriggerStack trigStackEntry;
757 :
758 : assert(op == TK_UPDATE || op == TK_INSERT || op == TK_DELETE);
759 : assert(tr_tm == TRIGGER_BEFORE || tr_tm == TRIGGER_AFTER );
760 :
761 : assert(newIdx != -1 || oldIdx != -1);
762 :
763 0 : for(p=pTab->pTrigger; p; p=p->pNext){
764 0 : int fire_this = 0;
765 :
766 : /* Determine whether we should code this trigger */
767 0 : if(
768 : p->op==op &&
769 : p->tr_tm==tr_tm &&
770 : (p->pSchema==p->pTabSchema || p->pSchema==pParse->db->aDb[1].pSchema) &&
771 : (op!=TK_UPDATE||!p->pColumns||checkColumnOverLap(p->pColumns,pChanges))
772 : ){
773 : TriggerStack *pS; /* Pointer to trigger-stack entry */
774 0 : for(pS=pParse->trigStack; pS && p!=pS->pTrigger; pS=pS->pNext){}
775 0 : if( !pS ){
776 0 : fire_this = 1;
777 : }
778 : #if 0 /* Give no warning for recursive triggers. Just do not do them */
779 : else{
780 : sqlite3ErrorMsg(pParse, "recursive triggers not supported (%s)",
781 : p->name);
782 : return SQLITE_ERROR;
783 : }
784 : #endif
785 : }
786 :
787 0 : if( fire_this ){
788 : int endTrigger;
789 : Expr * whenExpr;
790 : AuthContext sContext;
791 : NameContext sNC;
792 :
793 0 : memset(&sNC, 0, sizeof(sNC));
794 0 : sNC.pParse = pParse;
795 :
796 : /* Push an entry on to the trigger stack */
797 0 : trigStackEntry.pTrigger = p;
798 0 : trigStackEntry.newIdx = newIdx;
799 0 : trigStackEntry.oldIdx = oldIdx;
800 0 : trigStackEntry.pTab = pTab;
801 0 : trigStackEntry.pNext = pParse->trigStack;
802 0 : trigStackEntry.ignoreJump = ignoreJump;
803 0 : pParse->trigStack = &trigStackEntry;
804 0 : sqlite3AuthContextPush(pParse, &sContext, p->name);
805 :
806 : /* code the WHEN clause */
807 0 : endTrigger = sqlite3VdbeMakeLabel(pParse->pVdbe);
808 0 : whenExpr = sqlite3ExprDup(p->pWhen);
809 0 : if( sqlite3ExprResolveNames(&sNC, whenExpr) ){
810 0 : pParse->trigStack = trigStackEntry.pNext;
811 0 : sqlite3ExprDelete(whenExpr);
812 0 : return 1;
813 : }
814 0 : sqlite3ExprIfFalse(pParse, whenExpr, endTrigger, 1);
815 0 : sqlite3ExprDelete(whenExpr);
816 :
817 0 : codeTriggerProgram(pParse, p->step_list, orconf);
818 :
819 : /* Pop the entry off the trigger stack */
820 0 : pParse->trigStack = trigStackEntry.pNext;
821 0 : sqlite3AuthContextPop(&sContext);
822 :
823 0 : sqlite3VdbeResolveLabel(pParse->pVdbe, endTrigger);
824 : }
825 : }
826 0 : return 0;
827 : }
828 : #endif /* !defined(SQLITE_OMIT_TRIGGER) */
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