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gecko-dev/db/sqlite3/src/trigger.c

814 строки
27 KiB
C
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/*
**
** 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 ) sqliteFree((char*)pTmp->target.z);
sqlite3ExprDelete(pTmp->pWhere);
sqlite3ExprListDelete(pTmp->pExprList);
sqlite3SelectDelete(pTmp->pSelect);
sqlite3IdListDelete(pTmp->pIdList);
sqliteFree(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 */
int foreach, /* One of TK_ROW or TK_STATEMENT */
Expr *pWhen, /* WHEN clause */
int isTemp /* True if the TEMPORARY keyword is present */
){
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 || sqlite3MallocFailed() ){
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( sqlite3MallocFailed() ) 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;
}
/* Check that the trigger name is not reserved and that no trigger of the
** specified name exists */
zName = sqlite3NameFromToken(pName);
if( !zName || SQLITE_OK!=sqlite3CheckObjectName(pParse, zName) ){
goto trigger_cleanup;
}
if( sqlite3HashFind(&(db->aDb[iDb].pSchema->trigHash), zName,strlen(zName)) ){
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*)sqliteMalloc(sizeof(Trigger));
if( pTrigger==0 ) goto trigger_cleanup;
pTrigger->name = zName;
zName = 0;
pTrigger->table = sqliteStrDup(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(pWhen);
pTrigger->pColumns = sqlite3IdListDup(pColumns);
pTrigger->foreach = foreach;
sqlite3TokenCopy(&pTrigger->nameToken,pName);
assert( pParse->pNewTrigger==0 );
pParse->pNewTrigger = pTrigger;
trigger_cleanup:
sqliteFree(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 ){
static const VdbeOpList insertTrig[] = {
{ OP_NewRowid, 0, 0, 0 },
{ OP_String8, 0, 0, "trigger" },
{ OP_String8, 0, 0, 0 }, /* 2: trigger name */
{ OP_String8, 0, 0, 0 }, /* 3: table name */
{ OP_Integer, 0, 0, 0 },
{ OP_String8, 0, 0, "CREATE TRIGGER "},
{ OP_String8, 0, 0, 0 }, /* 6: SQL */
{ OP_Concat, 0, 0, 0 },
{ OP_MakeRecord, 5, 0, "aaada" },
{ OP_Insert, 0, 0, 0 },
};
int addr;
Vdbe *v;
/* Make an entry in the sqlite_master table */
v = sqlite3GetVdbe(pParse);
if( v==0 ) goto triggerfinish_cleanup;
sqlite3BeginWriteOperation(pParse, 0, iDb);
sqlite3OpenMasterTable(pParse, iDb);
addr = sqlite3VdbeAddOpList(v, ArraySize(insertTrig), insertTrig);
sqlite3VdbeChangeP3(v, addr+2, pTrig->name, 0);
sqlite3VdbeChangeP3(v, addr+3, pTrig->table, 0);
sqlite3VdbeChangeP3(v, addr+6, (char*)pAll->z, pAll->n);
sqlite3ChangeCookie(db, v, iDb);
sqlite3VdbeAddOp(v, OP_Close, 0, 0);
sqlite3VdbeOp3(v, OP_ParseSchema, iDb, 0,
sqlite3MPrintf("type='trigger' AND name='%q'", pTrig->name), P3_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( sqlite3MallocFailed() && pDel==pTrig );
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 sqliteMalloc(). 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(TriggerStep *p){
if( p->target.z ){
p->target.z = (u8*)sqliteStrNDup((char*)p->target.z, p->target.n);
p->target.dyn = 1;
}
if( p->pSelect ){
Select *pNew = sqlite3SelectDup(p->pSelect);
sqlite3SelectDelete(p->pSelect);
p->pSelect = pNew;
}
if( p->pWhere ){
Expr *pNew = sqlite3ExprDup(p->pWhere);
sqlite3ExprDelete(p->pWhere);
p->pWhere = pNew;
}
if( p->pExprList ){
ExprList *pNew = sqlite3ExprListDup(p->pExprList);
sqlite3ExprListDelete(p->pExprList);
p->pExprList = pNew;
}
if( p->pIdList ){
IdList *pNew = sqlite3IdListDup(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(Select *pSelect){
TriggerStep *pTriggerStep = sqliteMalloc(sizeof(TriggerStep));
if( pTriggerStep==0 ) {
sqlite3SelectDelete(pSelect);
return 0;
}
pTriggerStep->op = TK_SELECT;
pTriggerStep->pSelect = pSelect;
pTriggerStep->orconf = OE_Default;
sqlitePersistTriggerStep(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(
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 = sqliteMalloc(sizeof(TriggerStep));
assert(pEList == 0 || pSelect == 0);
assert(pEList != 0 || pSelect != 0);
if( pTriggerStep ){
pTriggerStep->op = TK_INSERT;
pTriggerStep->pSelect = pSelect;
pTriggerStep->target = *pTableName;
pTriggerStep->pIdList = pColumn;
pTriggerStep->pExprList = pEList;
pTriggerStep->orconf = orconf;
sqlitePersistTriggerStep(pTriggerStep);
}else{
sqlite3IdListDelete(pColumn);
sqlite3ExprListDelete(pEList);
sqlite3SelectDup(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(
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 = sqliteMalloc(sizeof(TriggerStep));
if( pTriggerStep==0 ) return 0;
pTriggerStep->op = TK_UPDATE;
pTriggerStep->target = *pTableName;
pTriggerStep->pExprList = pEList;
pTriggerStep->pWhere = pWhere;
pTriggerStep->orconf = orconf;
sqlitePersistTriggerStep(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(Token *pTableName, Expr *pWhere){
TriggerStep *pTriggerStep = sqliteMalloc(sizeof(TriggerStep));
if( pTriggerStep==0 ) return 0;
pTriggerStep->op = TK_DELETE;
pTriggerStep->target = *pTableName;
pTriggerStep->pWhere = pWhere;
pTriggerStep->orconf = OE_Default;
sqlitePersistTriggerStep(pTriggerStep);
return pTriggerStep;
}
/*
** Recursively delete a Trigger structure
*/
void sqlite3DeleteTrigger(Trigger *pTrigger){
if( pTrigger==0 ) return;
sqlite3DeleteTriggerStep(pTrigger->step_list);
sqliteFree(pTrigger->name);
sqliteFree(pTrigger->table);
sqlite3ExprDelete(pTrigger->pWhen);
sqlite3IdListDelete(pTrigger->pColumns);
if( pTrigger->nameToken.dyn ) sqliteFree((char*)pTrigger->nameToken.z);
sqliteFree(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){
Trigger *pTrigger = 0;
int i;
const char *zDb;
const char *zName;
int nName;
sqlite3 *db = pParse->db;
if( sqlite3MallocFailed() ) 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 ){
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, 0, 0}, /* 1 */
{ OP_Column, 0, 1, 0},
{ OP_Ne, 0, ADDR(8), 0},
{ OP_String8, 0, 0, "trigger"},
{ OP_Column, 0, 0, 0},
{ OP_Ne, 0, ADDR(8), 0},
{ 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);
sqlite3VdbeChangeP3(v, base+1, pTrigger->name, 0);
sqlite3ChangeCookie(db, v, iDb);
sqlite3VdbeAddOp(v, OP_Close, 0, 0);
sqlite3VdbeOp3(v, OP_DropTrigger, iDb, 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 = pTab->pTrigger;
int mask = 0;
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(0, &sDb, &pStep->target);
} else {
pSrc = sqlite3SrcListAppend(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;
assert( pTriggerStep!=0 );
assert( v!=0 );
sqlite3VdbeAddOp(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(pTriggerStep->pSelect);
assert(ss);
assert(ss->pSrc);
sqlite3SelectResolve(pParse, ss, 0);
sqlite3Select(pParse, ss, SRT_Discard, 0, 0, 0, 0, 0);
sqlite3SelectDelete(ss);
break;
}
case TK_UPDATE: {
SrcList *pSrc;
pSrc = targetSrcList(pParse, pTriggerStep);
sqlite3VdbeAddOp(v, OP_ResetCount, 0, 0);
sqlite3Update(pParse, pSrc,
sqlite3ExprListDup(pTriggerStep->pExprList),
sqlite3ExprDup(pTriggerStep->pWhere), orconf);
sqlite3VdbeAddOp(v, OP_ResetCount, 1, 0);
break;
}
case TK_INSERT: {
SrcList *pSrc;
pSrc = targetSrcList(pParse, pTriggerStep);
sqlite3VdbeAddOp(v, OP_ResetCount, 0, 0);
sqlite3Insert(pParse, pSrc,
sqlite3ExprListDup(pTriggerStep->pExprList),
sqlite3SelectDup(pTriggerStep->pSelect),
sqlite3IdListDup(pTriggerStep->pIdList), orconf);
sqlite3VdbeAddOp(v, OP_ResetCount, 1, 0);
break;
}
case TK_DELETE: {
SrcList *pSrc;
sqlite3VdbeAddOp(v, OP_ResetCount, 0, 0);
pSrc = targetSrcList(pParse, pTriggerStep);
sqlite3DeleteFrom(pParse, pSrc, sqlite3ExprDup(pTriggerStep->pWhere));
sqlite3VdbeAddOp(v, OP_ResetCount, 1, 0);
break;
}
default:
assert(0);
}
pTriggerStep = pTriggerStep->pNext;
}
sqlite3VdbeAddOp(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).
**
*/
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) */
){
Trigger *p;
TriggerStack trigStackEntry;
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==pParse->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;
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(p->pWhen);
if( sqlite3ExprResolveNames(&sNC, whenExpr) ){
pParse->trigStack = trigStackEntry.pNext;
sqlite3ExprDelete(whenExpr);
return 1;
}
sqlite3ExprIfFalse(pParse, whenExpr, endTrigger, 1);
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);
}
}
return 0;
}
#endif /* !defined(SQLITE_OMIT_TRIGGER) */
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