trigger.c
上传用户:sunhongbo
上传日期:2022-01-25
资源大小:3010k
文件大小:28k
- /*
- **
- ** The author disclaims copyright to this source code. In place of
- ** a legal notice, here is a blessing:
- **
- ** May you do good and not evil.
- ** May you find forgiveness for yourself and forgive others.
- ** May you share freely, never taking more than you give.
- **
- *************************************************************************
- *
- */
- #include "sqliteInt.h"
- #ifndef SQLITE_OMIT_TRIGGER
- /*
- ** Delete a linked list of TriggerStep structures.
- */
- void sqlite3DeleteTriggerStep(TriggerStep *pTriggerStep){
- while( pTriggerStep ){
- TriggerStep * pTmp = pTriggerStep;
- pTriggerStep = pTriggerStep->pNext;
- if( pTmp->target.dyn ) sqlite3_free((char*)pTmp->target.z);
- sqlite3ExprDelete(pTmp->pWhere);
- sqlite3ExprListDelete(pTmp->pExprList);
- sqlite3SelectDelete(pTmp->pSelect);
- sqlite3IdListDelete(pTmp->pIdList);
- sqlite3_free(pTmp);
- }
- }
- /*
- ** This is called by the parser when it sees a CREATE TRIGGER statement
- ** up to the point of the BEGIN before the trigger actions. A Trigger
- ** structure is generated based on the information available and stored
- ** in pParse->pNewTrigger. After the trigger actions have been parsed, the
- ** sqlite3FinishTrigger() function is called to complete the trigger
- ** construction process.
- */
- void sqlite3BeginTrigger(
- Parse *pParse, /* The parse context of the CREATE TRIGGER statement */
- Token *pName1, /* The name of the trigger */
- Token *pName2, /* The name of the trigger */
- int tr_tm, /* One of TK_BEFORE, TK_AFTER, TK_INSTEAD */
- int op, /* One of TK_INSERT, TK_UPDATE, TK_DELETE */
- IdList *pColumns, /* column list if this is an UPDATE OF trigger */
- SrcList *pTableName,/* The name of the table/view the trigger applies to */
- Expr *pWhen, /* WHEN clause */
- int isTemp, /* True if the TEMPORARY keyword is present */
- int noErr /* Suppress errors if the trigger already exists */
- ){
- Trigger *pTrigger = 0;
- Table *pTab;
- char *zName = 0; /* Name of the trigger */
- sqlite3 *db = pParse->db;
- int iDb; /* The database to store the trigger in */
- Token *pName; /* The unqualified db name */
- DbFixer sFix;
- int iTabDb;
- assert( pName1!=0 ); /* pName1->z might be NULL, but not pName1 itself */
- assert( pName2!=0 );
- if( isTemp ){
- /* If TEMP was specified, then the trigger name may not be qualified. */
- if( pName2->n>0 ){
- sqlite3ErrorMsg(pParse, "temporary trigger may not have qualified name");
- goto trigger_cleanup;
- }
- iDb = 1;
- pName = pName1;
- }else{
- /* Figure out the db that the the trigger will be created in */
- iDb = sqlite3TwoPartName(pParse, pName1, pName2, &pName);
- if( iDb<0 ){
- goto trigger_cleanup;
- }
- }
- /* If the trigger name was unqualified, and the table is a temp table,
- ** then set iDb to 1 to create the trigger in the temporary database.
- ** If sqlite3SrcListLookup() returns 0, indicating the table does not
- ** exist, the error is caught by the block below.
- */
- if( !pTableName || db->mallocFailed ){
- goto trigger_cleanup;
- }
- pTab = sqlite3SrcListLookup(pParse, pTableName);
- if( pName2->n==0 && pTab && pTab->pSchema==db->aDb[1].pSchema ){
- iDb = 1;
- }
- /* Ensure the table name matches database name and that the table exists */
- if( db->mallocFailed ) goto trigger_cleanup;
- assert( pTableName->nSrc==1 );
- if( sqlite3FixInit(&sFix, pParse, iDb, "trigger", pName) &&
- sqlite3FixSrcList(&sFix, pTableName) ){
- goto trigger_cleanup;
- }
- pTab = sqlite3SrcListLookup(pParse, pTableName);
- if( !pTab ){
- /* The table does not exist. */
- goto trigger_cleanup;
- }
- if( IsVirtual(pTab) ){
- sqlite3ErrorMsg(pParse, "cannot create triggers on virtual tables");
- goto trigger_cleanup;
- }
- /* Check that the trigger name is not reserved and that no trigger of the
- ** specified name exists */
- zName = sqlite3NameFromToken(db, pName);
- if( !zName || SQLITE_OK!=sqlite3CheckObjectName(pParse, zName) ){
- goto trigger_cleanup;
- }
- if( sqlite3HashFind(&(db->aDb[iDb].pSchema->trigHash), zName,strlen(zName)) ){
- if( !noErr ){
- sqlite3ErrorMsg(pParse, "trigger %T already exists", pName);
- }
- goto trigger_cleanup;
- }
- /* Do not create a trigger on a system table */
- if( sqlite3StrNICmp(pTab->zName, "sqlite_", 7)==0 ){
- sqlite3ErrorMsg(pParse, "cannot create trigger on system table");
- pParse->nErr++;
- goto trigger_cleanup;
- }
- /* INSTEAD of triggers are only for views and views only support INSTEAD
- ** of triggers.
- */
- if( pTab->pSelect && tr_tm!=TK_INSTEAD ){
- sqlite3ErrorMsg(pParse, "cannot create %s trigger on view: %S",
- (tr_tm == TK_BEFORE)?"BEFORE":"AFTER", pTableName, 0);
- goto trigger_cleanup;
- }
- if( !pTab->pSelect && tr_tm==TK_INSTEAD ){
- sqlite3ErrorMsg(pParse, "cannot create INSTEAD OF"
- " trigger on table: %S", pTableName, 0);
- goto trigger_cleanup;
- }
- iTabDb = sqlite3SchemaToIndex(db, pTab->pSchema);
- #ifndef SQLITE_OMIT_AUTHORIZATION
- {
- int code = SQLITE_CREATE_TRIGGER;
- const char *zDb = db->aDb[iTabDb].zName;
- const char *zDbTrig = isTemp ? db->aDb[1].zName : zDb;
- if( iTabDb==1 || isTemp ) code = SQLITE_CREATE_TEMP_TRIGGER;
- if( sqlite3AuthCheck(pParse, code, zName, pTab->zName, zDbTrig) ){
- goto trigger_cleanup;
- }
- if( sqlite3AuthCheck(pParse, SQLITE_INSERT, SCHEMA_TABLE(iTabDb),0,zDb)){
- goto trigger_cleanup;
- }
- }
- #endif
- /* INSTEAD OF triggers can only appear on views and BEFORE triggers
- ** cannot appear on views. So we might as well translate every
- ** INSTEAD OF trigger into a BEFORE trigger. It simplifies code
- ** elsewhere.
- */
- if (tr_tm == TK_INSTEAD){
- tr_tm = TK_BEFORE;
- }
- /* Build the Trigger object */
- pTrigger = (Trigger*)sqlite3DbMallocZero(db, sizeof(Trigger));
- if( pTrigger==0 ) goto trigger_cleanup;
- pTrigger->name = zName;
- zName = 0;
- pTrigger->table = sqlite3DbStrDup(db, pTableName->a[0].zName);
- pTrigger->pSchema = db->aDb[iDb].pSchema;
- pTrigger->pTabSchema = pTab->pSchema;
- pTrigger->op = op;
- pTrigger->tr_tm = tr_tm==TK_BEFORE ? TRIGGER_BEFORE : TRIGGER_AFTER;
- pTrigger->pWhen = sqlite3ExprDup(db, pWhen);
- pTrigger->pColumns = sqlite3IdListDup(db, pColumns);
- sqlite3TokenCopy(db, &pTrigger->nameToken,pName);
- assert( pParse->pNewTrigger==0 );
- pParse->pNewTrigger = pTrigger;
- trigger_cleanup:
- sqlite3_free(zName);
- sqlite3SrcListDelete(pTableName);
- sqlite3IdListDelete(pColumns);
- sqlite3ExprDelete(pWhen);
- if( !pParse->pNewTrigger ){
- sqlite3DeleteTrigger(pTrigger);
- }else{
- assert( pParse->pNewTrigger==pTrigger );
- }
- }
- /*
- ** This routine is called after all of the trigger actions have been parsed
- ** in order to complete the process of building the trigger.
- */
- void sqlite3FinishTrigger(
- Parse *pParse, /* Parser context */
- TriggerStep *pStepList, /* The triggered program */
- Token *pAll /* Token that describes the complete CREATE TRIGGER */
- ){
- Trigger *pTrig = 0; /* The trigger whose construction is finishing up */
- sqlite3 *db = pParse->db; /* The database */
- DbFixer sFix;
- int iDb; /* Database containing the trigger */
- pTrig = pParse->pNewTrigger;
- pParse->pNewTrigger = 0;
- if( pParse->nErr || !pTrig ) goto triggerfinish_cleanup;
- iDb = sqlite3SchemaToIndex(pParse->db, pTrig->pSchema);
- pTrig->step_list = pStepList;
- while( pStepList ){
- pStepList->pTrig = pTrig;
- pStepList = pStepList->pNext;
- }
- if( sqlite3FixInit(&sFix, pParse, iDb, "trigger", &pTrig->nameToken)
- && sqlite3FixTriggerStep(&sFix, pTrig->step_list) ){
- goto triggerfinish_cleanup;
- }
- /* if we are not initializing, and this trigger is not on a TEMP table,
- ** build the sqlite_master entry
- */
- if( !db->init.busy ){
- Vdbe *v;
- char *z;
- /* Make an entry in the sqlite_master table */
- v = sqlite3GetVdbe(pParse);
- if( v==0 ) goto triggerfinish_cleanup;
- sqlite3BeginWriteOperation(pParse, 0, iDb);
- z = sqlite3DbStrNDup(db, (char*)pAll->z, pAll->n);
- sqlite3NestedParse(pParse,
- "INSERT INTO %Q.%s VALUES('trigger',%Q,%Q,0,'CREATE TRIGGER %q')",
- db->aDb[iDb].zName, SCHEMA_TABLE(iDb), pTrig->name,
- pTrig->table, z);
- sqlite3_free(z);
- sqlite3ChangeCookie(pParse, iDb);
- sqlite3VdbeAddOp4(v, OP_ParseSchema, iDb, 0, 0, sqlite3MPrintf(
- db, "type='trigger' AND name='%q'", pTrig->name), P4_DYNAMIC
- );
- }
- if( db->init.busy ){
- int n;
- Table *pTab;
- Trigger *pDel;
- pDel = sqlite3HashInsert(&db->aDb[iDb].pSchema->trigHash,
- pTrig->name, strlen(pTrig->name), pTrig);
- if( pDel ){
- assert( pDel==pTrig );
- db->mallocFailed = 1;
- goto triggerfinish_cleanup;
- }
- n = strlen(pTrig->table) + 1;
- pTab = sqlite3HashFind(&pTrig->pTabSchema->tblHash, pTrig->table, n);
- assert( pTab!=0 );
- pTrig->pNext = pTab->pTrigger;
- pTab->pTrigger = pTrig;
- pTrig = 0;
- }
- triggerfinish_cleanup:
- sqlite3DeleteTrigger(pTrig);
- assert( !pParse->pNewTrigger );
- sqlite3DeleteTriggerStep(pStepList);
- }
- /*
- ** Make a copy of all components of the given trigger step. This has
- ** the effect of copying all Expr.token.z values into memory obtained
- ** from sqlite3_malloc(). As initially created, the Expr.token.z values
- ** all point to the input string that was fed to the parser. But that
- ** string is ephemeral - it will go away as soon as the sqlite3_exec()
- ** call that started the parser exits. This routine makes a persistent
- ** copy of all the Expr.token.z strings so that the TriggerStep structure
- ** will be valid even after the sqlite3_exec() call returns.
- */
- static void sqlitePersistTriggerStep(sqlite3 *db, TriggerStep *p){
- if( p->target.z ){
- p->target.z = (u8*)sqlite3DbStrNDup(db, (char*)p->target.z, p->target.n);
- p->target.dyn = 1;
- }
- if( p->pSelect ){
- Select *pNew = sqlite3SelectDup(db, p->pSelect);
- sqlite3SelectDelete(p->pSelect);
- p->pSelect = pNew;
- }
- if( p->pWhere ){
- Expr *pNew = sqlite3ExprDup(db, p->pWhere);
- sqlite3ExprDelete(p->pWhere);
- p->pWhere = pNew;
- }
- if( p->pExprList ){
- ExprList *pNew = sqlite3ExprListDup(db, p->pExprList);
- sqlite3ExprListDelete(p->pExprList);
- p->pExprList = pNew;
- }
- if( p->pIdList ){
- IdList *pNew = sqlite3IdListDup(db, p->pIdList);
- sqlite3IdListDelete(p->pIdList);
- p->pIdList = pNew;
- }
- }
- /*
- ** Turn a SELECT statement (that the pSelect parameter points to) into
- ** a trigger step. Return a pointer to a TriggerStep structure.
- **
- ** The parser calls this routine when it finds a SELECT statement in
- ** body of a TRIGGER.
- */
- TriggerStep *sqlite3TriggerSelectStep(sqlite3 *db, Select *pSelect){
- TriggerStep *pTriggerStep = sqlite3DbMallocZero(db, sizeof(TriggerStep));
- if( pTriggerStep==0 ) {
- sqlite3SelectDelete(pSelect);
- return 0;
- }
- pTriggerStep->op = TK_SELECT;
- pTriggerStep->pSelect = pSelect;
- pTriggerStep->orconf = OE_Default;
- sqlitePersistTriggerStep(db, pTriggerStep);
- return pTriggerStep;
- }
- /*
- ** Build a trigger step out of an INSERT statement. Return a pointer
- ** to the new trigger step.
- **
- ** The parser calls this routine when it sees an INSERT inside the
- ** body of a trigger.
- */
- TriggerStep *sqlite3TriggerInsertStep(
- sqlite3 *db, /* The database connection */
- Token *pTableName, /* Name of the table into which we insert */
- IdList *pColumn, /* List of columns in pTableName to insert into */
- ExprList *pEList, /* The VALUE clause: a list of values to be inserted */
- Select *pSelect, /* A SELECT statement that supplies values */
- int orconf /* The conflict algorithm (OE_Abort, OE_Replace, etc.) */
- ){
- TriggerStep *pTriggerStep;
- assert(pEList == 0 || pSelect == 0);
- assert(pEList != 0 || pSelect != 0 || db->mallocFailed);
- pTriggerStep = sqlite3DbMallocZero(db, sizeof(TriggerStep));
- if( pTriggerStep ){
- pTriggerStep->op = TK_INSERT;
- pTriggerStep->pSelect = pSelect;
- pTriggerStep->target = *pTableName;
- pTriggerStep->pIdList = pColumn;
- pTriggerStep->pExprList = pEList;
- pTriggerStep->orconf = orconf;
- sqlitePersistTriggerStep(db, pTriggerStep);
- }else{
- sqlite3IdListDelete(pColumn);
- sqlite3ExprListDelete(pEList);
- sqlite3SelectDelete(pSelect);
- }
- return pTriggerStep;
- }
- /*
- ** Construct a trigger step that implements an UPDATE statement and return
- ** a pointer to that trigger step. The parser calls this routine when it
- ** sees an UPDATE statement inside the body of a CREATE TRIGGER.
- */
- TriggerStep *sqlite3TriggerUpdateStep(
- sqlite3 *db, /* The database connection */
- Token *pTableName, /* Name of the table to be updated */
- ExprList *pEList, /* The SET clause: list of column and new values */
- Expr *pWhere, /* The WHERE clause */
- int orconf /* The conflict algorithm. (OE_Abort, OE_Ignore, etc) */
- ){
- TriggerStep *pTriggerStep = sqlite3DbMallocZero(db, sizeof(TriggerStep));
- if( pTriggerStep==0 ){
- sqlite3ExprListDelete(pEList);
- sqlite3ExprDelete(pWhere);
- return 0;
- }
- pTriggerStep->op = TK_UPDATE;
- pTriggerStep->target = *pTableName;
- pTriggerStep->pExprList = pEList;
- pTriggerStep->pWhere = pWhere;
- pTriggerStep->orconf = orconf;
- sqlitePersistTriggerStep(db, pTriggerStep);
- return pTriggerStep;
- }
- /*
- ** Construct a trigger step that implements a DELETE statement and return
- ** a pointer to that trigger step. The parser calls this routine when it
- ** sees a DELETE statement inside the body of a CREATE TRIGGER.
- */
- TriggerStep *sqlite3TriggerDeleteStep(
- sqlite3 *db, /* Database connection */
- Token *pTableName, /* The table from which rows are deleted */
- Expr *pWhere /* The WHERE clause */
- ){
- TriggerStep *pTriggerStep = sqlite3DbMallocZero(db, sizeof(TriggerStep));
- if( pTriggerStep==0 ){
- sqlite3ExprDelete(pWhere);
- return 0;
- }
- pTriggerStep->op = TK_DELETE;
- pTriggerStep->target = *pTableName;
- pTriggerStep->pWhere = pWhere;
- pTriggerStep->orconf = OE_Default;
- sqlitePersistTriggerStep(db, pTriggerStep);
- return pTriggerStep;
- }
- /*
- ** Recursively delete a Trigger structure
- */
- void sqlite3DeleteTrigger(Trigger *pTrigger){
- if( pTrigger==0 ) return;
- sqlite3DeleteTriggerStep(pTrigger->step_list);
- sqlite3_free(pTrigger->name);
- sqlite3_free(pTrigger->table);
- sqlite3ExprDelete(pTrigger->pWhen);
- sqlite3IdListDelete(pTrigger->pColumns);
- if( pTrigger->nameToken.dyn ) sqlite3_free((char*)pTrigger->nameToken.z);
- sqlite3_free(pTrigger);
- }
- /*
- ** This function is called to drop a trigger from the database schema.
- **
- ** This may be called directly from the parser and therefore identifies
- ** the trigger by name. The sqlite3DropTriggerPtr() routine does the
- ** same job as this routine except it takes a pointer to the trigger
- ** instead of the trigger name.
- **/
- void sqlite3DropTrigger(Parse *pParse, SrcList *pName, int noErr){
- Trigger *pTrigger = 0;
- int i;
- const char *zDb;
- const char *zName;
- int nName;
- sqlite3 *db = pParse->db;
- if( db->mallocFailed ) goto drop_trigger_cleanup;
- if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
- goto drop_trigger_cleanup;
- }
- assert( pName->nSrc==1 );
- zDb = pName->a[0].zDatabase;
- zName = pName->a[0].zName;
- nName = strlen(zName);
- for(i=OMIT_TEMPDB; i<db->nDb; i++){
- int j = (i<2) ? i^1 : i; /* Search TEMP before MAIN */
- if( zDb && sqlite3StrICmp(db->aDb[j].zName, zDb) ) continue;
- pTrigger = sqlite3HashFind(&(db->aDb[j].pSchema->trigHash), zName, nName);
- if( pTrigger ) break;
- }
- if( !pTrigger ){
- if( !noErr ){
- sqlite3ErrorMsg(pParse, "no such trigger: %S", pName, 0);
- }
- goto drop_trigger_cleanup;
- }
- sqlite3DropTriggerPtr(pParse, pTrigger);
- drop_trigger_cleanup:
- sqlite3SrcListDelete(pName);
- }
- /*
- ** Return a pointer to the Table structure for the table that a trigger
- ** is set on.
- */
- static Table *tableOfTrigger(Trigger *pTrigger){
- int n = strlen(pTrigger->table) + 1;
- return sqlite3HashFind(&pTrigger->pTabSchema->tblHash, pTrigger->table, n);
- }
- /*
- ** Drop a trigger given a pointer to that trigger.
- */
- void sqlite3DropTriggerPtr(Parse *pParse, Trigger *pTrigger){
- Table *pTable;
- Vdbe *v;
- sqlite3 *db = pParse->db;
- int iDb;
- iDb = sqlite3SchemaToIndex(pParse->db, pTrigger->pSchema);
- assert( iDb>=0 && iDb<db->nDb );
- pTable = tableOfTrigger(pTrigger);
- assert( pTable );
- assert( pTable->pSchema==pTrigger->pSchema || iDb==1 );
- #ifndef SQLITE_OMIT_AUTHORIZATION
- {
- int code = SQLITE_DROP_TRIGGER;
- const char *zDb = db->aDb[iDb].zName;
- const char *zTab = SCHEMA_TABLE(iDb);
- if( iDb==1 ) code = SQLITE_DROP_TEMP_TRIGGER;
- if( sqlite3AuthCheck(pParse, code, pTrigger->name, pTable->zName, zDb) ||
- sqlite3AuthCheck(pParse, SQLITE_DELETE, zTab, 0, zDb) ){
- return;
- }
- }
- #endif
- /* Generate code to destroy the database record of the trigger.
- */
- assert( pTable!=0 );
- if( (v = sqlite3GetVdbe(pParse))!=0 ){
- int base;
- static const VdbeOpList dropTrigger[] = {
- { OP_Rewind, 0, ADDR(9), 0},
- { OP_String8, 0, 1, 0}, /* 1 */
- { OP_Column, 0, 1, 2},
- { OP_Ne, 2, ADDR(8), 1},
- { OP_String8, 0, 1, 0}, /* 4: "trigger" */
- { OP_Column, 0, 0, 2},
- { OP_Ne, 2, ADDR(8), 1},
- { OP_Delete, 0, 0, 0},
- { OP_Next, 0, ADDR(1), 0}, /* 8 */
- };
- sqlite3BeginWriteOperation(pParse, 0, iDb);
- sqlite3OpenMasterTable(pParse, iDb);
- base = sqlite3VdbeAddOpList(v, ArraySize(dropTrigger), dropTrigger);
- sqlite3VdbeChangeP4(v, base+1, pTrigger->name, 0);
- sqlite3VdbeChangeP4(v, base+4, "trigger", P4_STATIC);
- sqlite3ChangeCookie(pParse, iDb);
- sqlite3VdbeAddOp2(v, OP_Close, 0, 0);
- sqlite3VdbeAddOp4(v, OP_DropTrigger, iDb, 0, 0, pTrigger->name, 0);
- }
- }
- /*
- ** Remove a trigger from the hash tables of the sqlite* pointer.
- */
- void sqlite3UnlinkAndDeleteTrigger(sqlite3 *db, int iDb, const char *zName){
- Trigger *pTrigger;
- int nName = strlen(zName);
- pTrigger = sqlite3HashInsert(&(db->aDb[iDb].pSchema->trigHash),
- zName, nName, 0);
- if( pTrigger ){
- Table *pTable = tableOfTrigger(pTrigger);
- assert( pTable!=0 );
- if( pTable->pTrigger == pTrigger ){
- pTable->pTrigger = pTrigger->pNext;
- }else{
- Trigger *cc = pTable->pTrigger;
- while( cc ){
- if( cc->pNext == pTrigger ){
- cc->pNext = cc->pNext->pNext;
- break;
- }
- cc = cc->pNext;
- }
- assert(cc);
- }
- sqlite3DeleteTrigger(pTrigger);
- db->flags |= SQLITE_InternChanges;
- }
- }
- /*
- ** pEList is the SET clause of an UPDATE statement. Each entry
- ** in pEList is of the format <id>=<expr>. If any of the entries
- ** in pEList have an <id> which matches an identifier in pIdList,
- ** then return TRUE. If pIdList==NULL, then it is considered a
- ** wildcard that matches anything. Likewise if pEList==NULL then
- ** it matches anything so always return true. Return false only
- ** if there is no match.
- */
- static int checkColumnOverLap(IdList *pIdList, ExprList *pEList){
- int e;
- if( !pIdList || !pEList ) return 1;
- for(e=0; e<pEList->nExpr; e++){
- if( sqlite3IdListIndex(pIdList, pEList->a[e].zName)>=0 ) return 1;
- }
- return 0;
- }
- /*
- ** Return a bit vector to indicate what kind of triggers exist for operation
- ** "op" on table pTab. If pChanges is not NULL then it is a list of columns
- ** that are being updated. Triggers only match if the ON clause of the
- ** trigger definition overlaps the set of columns being updated.
- **
- ** The returned bit vector is some combination of TRIGGER_BEFORE and
- ** TRIGGER_AFTER.
- */
- int sqlite3TriggersExist(
- Parse *pParse, /* Used to check for recursive triggers */
- Table *pTab, /* The table the contains the triggers */
- int op, /* one of TK_DELETE, TK_INSERT, TK_UPDATE */
- ExprList *pChanges /* Columns that change in an UPDATE statement */
- ){
- Trigger *pTrigger;
- int mask = 0;
- pTrigger = IsVirtual(pTab) ? 0 : pTab->pTrigger;
- while( pTrigger ){
- if( pTrigger->op==op && checkColumnOverLap(pTrigger->pColumns, pChanges) ){
- mask |= pTrigger->tr_tm;
- }
- pTrigger = pTrigger->pNext;
- }
- return mask;
- }
- /*
- ** Convert the pStep->target token into a SrcList and return a pointer
- ** to that SrcList.
- **
- ** This routine adds a specific database name, if needed, to the target when
- ** forming the SrcList. This prevents a trigger in one database from
- ** referring to a target in another database. An exception is when the
- ** trigger is in TEMP in which case it can refer to any other database it
- ** wants.
- */
- static SrcList *targetSrcList(
- Parse *pParse, /* The parsing context */
- TriggerStep *pStep /* The trigger containing the target token */
- ){
- Token sDb; /* Dummy database name token */
- int iDb; /* Index of the database to use */
- SrcList *pSrc; /* SrcList to be returned */
- iDb = sqlite3SchemaToIndex(pParse->db, pStep->pTrig->pSchema);
- if( iDb==0 || iDb>=2 ){
- assert( iDb<pParse->db->nDb );
- sDb.z = (u8*)pParse->db->aDb[iDb].zName;
- sDb.n = strlen((char*)sDb.z);
- pSrc = sqlite3SrcListAppend(pParse->db, 0, &sDb, &pStep->target);
- } else {
- pSrc = sqlite3SrcListAppend(pParse->db, 0, &pStep->target, 0);
- }
- return pSrc;
- }
- /*
- ** Generate VDBE code for zero or more statements inside the body of a
- ** trigger.
- */
- static int codeTriggerProgram(
- Parse *pParse, /* The parser context */
- TriggerStep *pStepList, /* List of statements inside the trigger body */
- int orconfin /* Conflict algorithm. (OE_Abort, etc) */
- ){
- TriggerStep * pTriggerStep = pStepList;
- int orconf;
- Vdbe *v = pParse->pVdbe;
- sqlite3 *db = pParse->db;
- assert( pTriggerStep!=0 );
- assert( v!=0 );
- sqlite3VdbeAddOp2(v, OP_ContextPush, 0, 0);
- VdbeComment((v, "begin trigger %s", pStepList->pTrig->name));
- while( pTriggerStep ){
- orconf = (orconfin == OE_Default)?pTriggerStep->orconf:orconfin;
- pParse->trigStack->orconf = orconf;
- switch( pTriggerStep->op ){
- case TK_SELECT: {
- Select *ss = sqlite3SelectDup(db, pTriggerStep->pSelect);
- if( ss ){
- SelectDest dest;
- sqlite3SelectDestInit(&dest, SRT_Discard, 0);
- sqlite3SelectResolve(pParse, ss, 0);
- sqlite3Select(pParse, ss, &dest, 0, 0, 0, 0);
- sqlite3SelectDelete(ss);
- }
- break;
- }
- case TK_UPDATE: {
- SrcList *pSrc;
- pSrc = targetSrcList(pParse, pTriggerStep);
- sqlite3VdbeAddOp2(v, OP_ResetCount, 0, 0);
- sqlite3Update(pParse, pSrc,
- sqlite3ExprListDup(db, pTriggerStep->pExprList),
- sqlite3ExprDup(db, pTriggerStep->pWhere), orconf);
- sqlite3VdbeAddOp2(v, OP_ResetCount, 1, 0);
- break;
- }
- case TK_INSERT: {
- SrcList *pSrc;
- pSrc = targetSrcList(pParse, pTriggerStep);
- sqlite3VdbeAddOp2(v, OP_ResetCount, 0, 0);
- sqlite3Insert(pParse, pSrc,
- sqlite3ExprListDup(db, pTriggerStep->pExprList),
- sqlite3SelectDup(db, pTriggerStep->pSelect),
- sqlite3IdListDup(db, pTriggerStep->pIdList), orconf);
- sqlite3VdbeAddOp2(v, OP_ResetCount, 1, 0);
- break;
- }
- case TK_DELETE: {
- SrcList *pSrc;
- sqlite3VdbeAddOp2(v, OP_ResetCount, 0, 0);
- pSrc = targetSrcList(pParse, pTriggerStep);
- sqlite3DeleteFrom(pParse, pSrc,
- sqlite3ExprDup(db, pTriggerStep->pWhere));
- sqlite3VdbeAddOp2(v, OP_ResetCount, 1, 0);
- break;
- }
- default:
- assert(0);
- }
- pTriggerStep = pTriggerStep->pNext;
- }
- sqlite3VdbeAddOp2(v, OP_ContextPop, 0, 0);
- VdbeComment((v, "end trigger %s", pStepList->pTrig->name));
- return 0;
- }
- /*
- ** This is called to code FOR EACH ROW triggers.
- **
- ** When the code that this function generates is executed, the following
- ** must be true:
- **
- ** 1. No cursors may be open in the main database. (But newIdx and oldIdx
- ** can be indices of cursors in temporary tables. See below.)
- **
- ** 2. If the triggers being coded are ON INSERT or ON UPDATE triggers, then
- ** a temporary vdbe cursor (index newIdx) must be open and pointing at
- ** a row containing values to be substituted for new.* expressions in the
- ** trigger program(s).
- **
- ** 3. If the triggers being coded are ON DELETE or ON UPDATE triggers, then
- ** a temporary vdbe cursor (index oldIdx) must be open and pointing at
- ** a row containing values to be substituted for old.* expressions in the
- ** trigger program(s).
- **
- ** If they are not NULL, the piOldColMask and piNewColMask output variables
- ** are set to values that describe the columns used by the trigger program
- ** in the OLD.* and NEW.* tables respectively. If column N of the
- ** pseudo-table is read at least once, the corresponding bit of the output
- ** mask is set. If a column with an index greater than 32 is read, the
- ** output mask is set to the special value 0xffffffff.
- **
- */
- int sqlite3CodeRowTrigger(
- Parse *pParse, /* Parse context */
- int op, /* One of TK_UPDATE, TK_INSERT, TK_DELETE */
- ExprList *pChanges, /* Changes list for any UPDATE OF triggers */
- int tr_tm, /* One of TRIGGER_BEFORE, TRIGGER_AFTER */
- Table *pTab, /* The table to code triggers from */
- int newIdx, /* The indice of the "new" row to access */
- int oldIdx, /* The indice of the "old" row to access */
- int orconf, /* ON CONFLICT policy */
- int ignoreJump, /* Instruction to jump to for RAISE(IGNORE) */
- u32 *piOldColMask, /* OUT: Mask of columns used from the OLD.* table */
- u32 *piNewColMask /* OUT: Mask of columns used from the NEW.* table */
- ){
- Trigger *p;
- sqlite3 *db = pParse->db;
- TriggerStack trigStackEntry;
- trigStackEntry.oldColMask = 0;
- trigStackEntry.newColMask = 0;
- assert(op == TK_UPDATE || op == TK_INSERT || op == TK_DELETE);
- assert(tr_tm == TRIGGER_BEFORE || tr_tm == TRIGGER_AFTER );
- assert(newIdx != -1 || oldIdx != -1);
- for(p=pTab->pTrigger; p; p=p->pNext){
- int fire_this = 0;
- /* Determine whether we should code this trigger */
- if(
- p->op==op &&
- p->tr_tm==tr_tm &&
- (p->pSchema==p->pTabSchema || p->pSchema==db->aDb[1].pSchema) &&
- (op!=TK_UPDATE||!p->pColumns||checkColumnOverLap(p->pColumns,pChanges))
- ){
- TriggerStack *pS; /* Pointer to trigger-stack entry */
- for(pS=pParse->trigStack; pS && p!=pS->pTrigger; pS=pS->pNext){}
- if( !pS ){
- fire_this = 1;
- }
- #if 0 /* Give no warning for recursive triggers. Just do not do them */
- else{
- sqlite3ErrorMsg(pParse, "recursive triggers not supported (%s)",
- p->name);
- return SQLITE_ERROR;
- }
- #endif
- }
-
- if( fire_this ){
- int endTrigger;
- Expr * whenExpr;
- AuthContext sContext;
- NameContext sNC;
- #ifndef SQLITE_OMIT_TRACE
- sqlite3VdbeAddOp4(pParse->pVdbe, OP_Trace, 0, 0, 0,
- sqlite3MPrintf(db, "-- TRIGGER %s", p->name),
- P4_DYNAMIC);
- #endif
- memset(&sNC, 0, sizeof(sNC));
- sNC.pParse = pParse;
- /* Push an entry on to the trigger stack */
- trigStackEntry.pTrigger = p;
- trigStackEntry.newIdx = newIdx;
- trigStackEntry.oldIdx = oldIdx;
- trigStackEntry.pTab = pTab;
- trigStackEntry.pNext = pParse->trigStack;
- trigStackEntry.ignoreJump = ignoreJump;
- pParse->trigStack = &trigStackEntry;
- sqlite3AuthContextPush(pParse, &sContext, p->name);
- /* code the WHEN clause */
- endTrigger = sqlite3VdbeMakeLabel(pParse->pVdbe);
- whenExpr = sqlite3ExprDup(db, p->pWhen);
- if( db->mallocFailed || sqlite3ExprResolveNames(&sNC, whenExpr) ){
- pParse->trigStack = trigStackEntry.pNext;
- sqlite3ExprDelete(whenExpr);
- return 1;
- }
- sqlite3ExprIfFalse(pParse, whenExpr, endTrigger, SQLITE_JUMPIFNULL);
- sqlite3ExprDelete(whenExpr);
- codeTriggerProgram(pParse, p->step_list, orconf);
- /* Pop the entry off the trigger stack */
- pParse->trigStack = trigStackEntry.pNext;
- sqlite3AuthContextPop(&sContext);
- sqlite3VdbeResolveLabel(pParse->pVdbe, endTrigger);
- }
- }
- if( piOldColMask ) *piOldColMask |= trigStackEntry.oldColMask;
- if( piNewColMask ) *piNewColMask |= trigStackEntry.newColMask;
- return 0;
- }
- #endif /* !defined(SQLITE_OMIT_TRIGGER) */