/*
**
** 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"
/*
** Delete a linked list of TriggerStep structures.
*/
void sqliteDeleteTriggerStep(TriggerStep *pTriggerStep){
while( pTriggerStep ){
TriggerStep * pTmp = pTriggerStep;
pTriggerStep = pTriggerStep->pNext;
if( pTmp->target.dyn ) sqliteFree((char*)pTmp->target.z);
sqliteExprDelete(pTmp->pWhere);
sqliteExprListDelete(pTmp->pExprList);
sqliteSelectDelete(pTmp->pSelect);
sqliteIdListDelete(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
** sqliteFinishTrigger() function is called to complete the trigger
** construction process.
*/
void sqliteBeginTrigger(
Parse *pParse, /* The parse context of the CREATE TRIGGER statement */
Token *pName, /* 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 *nt;
Table *tab;
char *zName = 0; /* Name of the trigger */
sqlite *db = pParse->db;
int iDb; /* When database to store the trigger in */
DbFixer sFix;
/* Check that:
** 1. the trigger name does not already exist.
** 2. the table (or view) does exist in the same database as the trigger.
** 3. that we are not trying to create a trigger on the sqlite_master table
** 4. That we are not trying to create an INSTEAD OF trigger on a table.
** 5. That we are not trying to create a BEFORE or AFTER trigger on a view.
*/
if( sqlite_malloc_failed ) goto trigger_cleanup;
assert( pTableName->nSrc==1 );
if( db->init.busy
&& sqliteFixInit(&sFix, pParse, db->init.iDb, "trigger", pName)
&& sqliteFixSrcList(&sFix, pTableName)
){
goto trigger_cleanup;
}
tab = sqliteSrcListLookup(pParse, pTableName);
if( !tab ){
goto trigger_cleanup;
}
iDb = isTemp ? 1 : tab->iDb;
if( iDb>=2 && !db->init.busy ){
sqliteErrorMsg(pParse, "triggers may not be added to auxiliary "
"database %s", db->aDb[tab->iDb].zName);
goto trigger_cleanup;
}
zName = sqliteStrNDup(pName->z, pName->n);
sqliteDequote(zName);
if( sqliteHashFind(&(db->aDb[iDb].trigHash), zName,pName->n+1) ){
sqliteErrorMsg(pParse, "trigger %T already exists", pName);
goto trigger_cleanup;
}
if( sqliteStrNICmp(tab->zName, "sqlite_", 7)==0 ){
sqliteErrorMsg(pParse, "cannot create trigger on system table");
pParse->nErr++;
goto trigger_cleanup;
}
if( tab->pSelect && tr_tm != TK_INSTEAD ){
sqliteErrorMsg(pParse, "cannot create %s trigger on view: %S",
(tr_tm == TK_BEFORE)?"BEFORE":"AFTER", pTableName, 0);
goto trigger_cleanup;
}
if( !tab->pSelect && tr_tm == TK_INSTEAD ){
sqliteErrorMsg(pParse, "cannot create INSTEAD OF"
" trigger on table: %S", pTableName, 0);
goto trigger_cleanup;
}
#ifndef SQLITE_OMIT_AUTHORIZATION
{
int code = SQLITE_CREATE_TRIGGER;
const char *zDb = db->aDb[tab->iDb].zName;
const char *zDbTrig = isTemp ? db->aDb[1].zName : zDb;
if( tab->iDb==1 || isTemp ) code = SQLITE_CREATE_TEMP_TRIGGER;
if( sqliteAuthCheck(pParse, code, zName, tab->zName, zDbTrig) ){
goto trigger_cleanup;
}
if( sqliteAuthCheck(pParse, SQLITE_INSERT, SCHEMA_TABLE(tab->iDb), 0, zDb)){
goto trigger_cleanup;
}
}
#endif
/* INSTEAD OF triggers can only appear on views and BEGIN 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 */
nt = (Trigger*)sqliteMalloc(sizeof(Trigger));
if( nt==0 ) goto trigger_cleanup;
nt->name = zName;
zName = 0;
nt->table = sqliteStrDup(pTableName->a[0].zName);
if( sqlite_malloc_failed ) goto trigger_cleanup;
nt->iDb = iDb;
nt->iTabDb = tab->iDb;
nt->op = op;
nt->tr_tm = tr_tm;
nt->pWhen = sqliteExprDup(pWhen);
nt->pColumns = sqliteIdListDup(pColumns);
nt->foreach = foreach;
sqliteTokenCopy(&nt->nameToken,pName);
assert( pParse->pNewTrigger==0 );
pParse->pNewTrigger = nt;
trigger_cleanup:
sqliteFree(zName);
sqliteSrcListDelete(pTableName);
sqliteIdListDelete(pColumns);
sqliteExprDelete(pWhen);
}
/*
** This routine is called after all of the trigger actions have been parsed
** in order to complete the process of building the trigger.
*/
void sqliteFinishTrigger(
Parse *pParse, /* Parser context */
TriggerStep *pStepList, /* The triggered program */
Token *pAll /* Token that describes the complete CREATE TRIGGER */
){
Trigger *nt = 0; /* The trigger whose construction is finishing up */
sqlite *db = pParse->db; /* The database */
DbFixer sFix;
if( pParse->nErr || pParse->pNewTrigger==0 ) goto triggerfinish_cleanup;
nt = pParse->pNewTrigger;
pParse->pNewTrigger = 0;
nt->step_list = pStepList;
while( pStepList ){
pStepList->pTrig = nt;
pStepList = pStepList->pNext;
}
if( sqliteFixInit(&sFix, pParse, nt->iDb, "trigger", &nt->nameToken)
&& sqliteFixTriggerStep(&sFix, nt->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 VdbeOpList insertTrig[] = {
{ OP_NewRecno, 0, 0, 0 },
{ OP_String, 0, 0, "trigger" },
{ OP_String, 0, 0, 0 }, /* 2: trigger name */
{ OP_String, 0, 0, 0 }, /* 3: table name */
{ OP_Integer, 0, 0, 0 },
{ OP_String, 0, 0, 0 }, /* 5: SQL */
{ OP_MakeRecord, 5, 0, 0 },
{ OP_PutIntKey, 0, 0, 0 },
};
int addr;
Vdbe *v;
/* Make an entry in the sqlite_master table */
v = sqliteGetVdbe(pParse);
if( v==0 ) goto triggerfinish_cleanup;
sqliteBeginWriteOperation(pParse, 0, 0);
sqliteOpenMasterTable(v, nt->iDb);
addr = sqliteVdbeAddOpList(v, ArraySize(insertTrig), insertTrig);
sqliteVdbeChangeP3(v, addr+2, nt->name, 0);
sqliteVdbeChangeP3(v, addr+3, nt->table, 0);
sqliteVdbeChangeP3(v, addr+5, pAll->z, pAll->n);
if( nt->iDb==0 ){
sqliteChangeCookie(db, v);
}
sqliteVdbeAddOp(v, OP_Close, 0, 0);
sqliteEndWriteOperation(pParse);
}
if( !pParse->explain ){
Table *pTab;
sqliteHashInsert(&db->aDb[nt->iDb].trigHash,
nt->name, strlen(nt->name)+1, nt);
pTab = sqliteLocateTable(pParse, nt->table, db->aDb[nt->iTabDb].zName);
assert( pTab!=0 );
nt->pNext = pTab->pTrigger;
pTab->pTrigger = nt;
nt = 0;
}
triggerfinish_cleanup:
sqliteDeleteTrigger(nt);
sqliteDeleteTrigger(pParse->pNewTrigger);
pParse->pNewTrigger = 0;
sqliteDeleteTriggerStep(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 sqlite_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 sqlite_exec() call returns.
*/
static void sqlitePersistTriggerStep(TriggerStep *p){
if( p->target.z ){
p->target.z = sqliteStrNDup(p->target.z, p->target.n);
p->target.dyn = 1;
}
if( p->pSelect ){
Select *pNew = sqliteSelectDup(p->pSelect);
sqliteSelectDelete(p->pSelect);
p->pSelect = pNew;
}
if( p->pWhere ){
Expr *pNew = sqliteExprDup(p->pWhere);
sqliteExprDelete(p->pWhere);
p->pWhere = pNew;
}
if( p->pExprList ){
ExprList *pNew = sqliteExprListDup(p->pExprList);
sqliteExprListDelete(p->pExprList);
p->pExprList = pNew;
}
if( p->pIdList ){
IdList *pNew = sqliteIdListDup(p->pIdList);
sqliteIdListDelete(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 *sqliteTriggerSelectStep(Select *pSelect){
TriggerStep *pTriggerStep = sqliteMalloc(sizeof(TriggerStep));
if( pTriggerStep==0 ) 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 *sqliteTriggerInsertStep(
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));
if( pTriggerStep==0 ) return 0;
assert(pEList == 0 || pSelect == 0);
assert(pEList != 0 || pSelect != 0);
pTriggerStep->op = TK_INSERT;
pTriggerStep->pSelect = pSelect;
pTriggerStep->target = *pTableName;
pTriggerStep->pIdList = pColumn;
pTriggerStep->pExprList = pEList;
pTriggerStep->orconf = orconf;
sqlitePersistTriggerStep(pTriggerStep);
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 *sqliteTriggerUpdateStep(
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 *sqliteTriggerDeleteStep(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 sqliteDeleteTrigger(Trigger *pTrigger){
if( pTrigger==0 ) return;
sqliteDeleteTriggerStep(pTrigger->step_list);
sqliteFree(pTrigger->name);
sqliteFree(pTrigger->table);
sqliteExprDelete(pTrigger->pWhen);
sqliteIdListDelete(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 sqliteDropTriggerPtr() routine does the
* same job as this routine except it take a spointer to the trigger
* instead of the trigger name.
*
* Note that this function does not delete the trigger entirely. Instead it
* removes it from the internal schema and places it in the trigDrop hash
* table. This is so that the trigger can be restored into the database schema
* if the transaction is rolled back.
*/
void sqliteDropTrigger(Parse *pParse, SrcList *pName){
Trigger *pTrigger;
int i;
const char *zDb;
const char *zName;
int nName;
sqlite *db = pParse->db;
if( sqlite_malloc_failed ) goto drop_trigger_cleanup;
assert( pName->nSrc==1 );
zDb = pName->a[0].zDatabase;
zName = pName->a[0].zName;
nName = strlen(zName);
for(i=0; i<db->nDb; i++){
int j = (i<2) ? i^1 : i; /* Search TEMP before MAIN */
if( zDb && sqliteStrICmp(db->aDb[j].zName, zDb) ) continue;
pTrigger = sqliteHashFind(&(db->aDb[j].trigHash), zName, nName+1);
if( pTrigger ) break;
}
if( !pTrigger ){
sqliteErrorMsg(pParse, "no such trigger: %S", pName, 0);
goto drop_trigger_cleanup;
}
sqliteDropTriggerPtr(pParse, pTrigger, 0);
drop_trigger_cleanup:
sqliteSrcListDelete(pName);
}
/*
** Drop a trigger given a pointer to that trigger. If nested is false,
** then also generate code to remove the trigger from the SQLITE_MASTER
** table.
*/
void sqliteDropTriggerPtr(Parse *pParse, Trigger *pTrigger, int nested){
Table *pTable;
Vdbe *v;
sqlite *db = pParse->db;
assert( pTrigger->iDb<db->nDb );
if( pTrigger->iDb>=2 ){
sqliteErrorMsg(pParse, "triggers may not be removed from "
"auxiliary database %s", db->aDb[pTrigger->iDb].zName);
return;
}
pTable = sqliteFindTable(db, pTrigger->table,db->aDb[pTrigger->iTabDb].zName);
assert(pTable);
assert( pTable->iDb==pTrigger->iDb || pTrigger->iDb==1 );
#ifndef SQLITE_OMIT_AUTHORIZATION
{
int code = SQLITE_DROP_TRIGGER;
const char *zDb = db->aDb[pTrigger->iDb].zName;
const char *zTab = SCHEMA_TABLE(pTrigger->iDb);
if( pTrigger->iDb ) code = SQLITE_DROP_TEMP_TRIGGER;
if( sqliteAuthCheck(pParse, code, pTrigger->name, pTable->zName, zDb) ||
sqliteAuthCheck(pParse, SQLITE_DELETE, zTab, 0, zDb) ){
return;
}
}
#endif
/* Generate code to destroy the database record of the trigger.
*/
if( pTable!=0 && !nested && (v = sqliteGetVdbe(pParse))!=0 ){
int base;
static VdbeOpList dropTrigger[] = {
{ OP_Rewind, 0, ADDR(9), 0},
{ OP_String, 0, 0, 0}, /* 1 */
{ OP_Column, 0, 1, 0},
{ OP_Ne, 0, ADDR(8), 0},
{ OP_String, 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 */
};
sqliteBeginWriteOperation(pParse, 0, 0);
sqliteOpenMasterTable(v, pTrigger->iDb);
base = sqliteVdbeAddOpList(v, ArraySize(dropTrigger), dropTrigger);
sqliteVdbeChangeP3(v, base+1, pTrigger->name, 0);
if( pTrigger->iDb==0 ){
sqliteChangeCookie(db, v);
}
sqliteVdbeAddOp(v, OP_Close, 0, 0);
sqliteEndWriteOperation(pParse);
}
/*
* If this is not an "explain", then delete the trigger structure.
*/
if( !pParse->explain ){
const char *zName = pTrigger->name;
int nName = strlen(zName);
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);
}
sqliteHashInsert(&(db->aDb[pTrigger->iDb].trigHash), zName, nName+1, 0);
sqliteDeleteTrigger(pTrigger);
}
}
/*
** 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( sqliteIdListIndex(pIdList, pEList->a[e].zName)>=0 ) return 1;
}
return 0;
}
/* A global variable that is TRUE if we should always set up temp tables for
* for triggers, even if there are no triggers to code. This is used to test
* how much overhead the triggers algorithm is causing.
*
* This flag can be set or cleared using the "trigger_overhead_test" pragma.
* The pragma is not documented since it is not really part of the interface
* to SQLite, just the test procedure.
*/
int always_code_trigger_setup = 0;
/*
* Returns true if a trigger matching op, tr_tm and foreach that is NOT already
* on the Parse objects trigger-stack (to prevent recursive trigger firing) is
* found in the list specified as pTrigger.
*/
int sqliteTriggersExist(
Parse *pParse, /* Used to check for recursive triggers */
Trigger *pTrigger, /* A list of triggers associated with a table */
int op, /* one of TK_DELETE, TK_INSERT, TK_UPDATE */
int tr_tm, /* one of TK_BEFORE, TK_AFTER */
int foreach, /* one of TK_ROW or TK_STATEMENT */
ExprList *pChanges /* Columns that change in an UPDATE statement */
){
Trigger * pTriggerCursor;
if( always_code_trigger_setup ){
return 1;
}
pTriggerCursor = pTrigger;
while( pTriggerCursor ){
if( pTriggerCursor->op == op &&
pTriggerCursor->tr_tm == tr_tm &&
pTriggerCursor->foreach == foreach &&
checkColumnOverLap(pTriggerCursor->pColumns, pChanges) ){
TriggerStack * ss;
ss = pParse->trigStack;
while( ss && ss->pTrigger != pTrigger ){
ss = ss->pNext;
}
if( !ss )return 1;
}
pTriggerCursor = pTriggerCursor->pNext;
}
return 0;
}
/*
** 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 = pStep->pTrig->iDb;
if( iDb==0 || iDb>=2 ){
assert( iDb<pParse->db->nDb );
sDb.z = pParse->db->aDb[iDb].zName;
sDb.n = strlen(sDb.z);
pSrc = sqliteSrcListAppend(0, &sDb, &pStep->target);
} else {
pSrc = sqliteSrcListAppend(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;
while( pTriggerStep ){
int saveNTab = pParse->nTab;
orconf = (orconfin == OE_Default)?pTriggerStep->orconf:orconfin;
pParse->trigStack->orconf = orconf;
switch( pTriggerStep->op ){
case TK_SELECT: {
Select * ss = sqliteSelectDup(pTriggerStep->pSelect);
assert(ss);
assert(ss->pSrc);
sqliteSelect(pParse, ss, SRT_Discard, 0, 0, 0, 0);
sqliteSelectDelete(ss);
break;
}
case TK_UPDATE: {
SrcList *pSrc;
pSrc = targetSrcList(pParse, pTriggerStep);
sqliteVdbeAddOp(pParse->pVdbe, OP_ListPush, 0, 0);
sqliteUpdate(pParse, pSrc,
sqliteExprListDup(pTriggerStep->pExprList),
sqliteExprDup(pTriggerStep->pWhere), orconf);
sqliteVdbeAddOp(pParse->pVdbe, OP_ListPop, 0, 0);
break;
}
case TK_INSERT: {
SrcList *pSrc;
pSrc = targetSrcList(pParse, pTriggerStep);
sqliteInsert(pParse, pSrc,
sqliteExprListDup(pTriggerStep->pExprList),
sqliteSelectDup(pTriggerStep->pSelect),
sqliteIdListDup(pTriggerStep->pIdList), orconf);
break;
}
case TK_DELETE: {
SrcList *pSrc;
sqliteVdbeAddOp(pParse->pVdbe, OP_ListPush, 0, 0);
pSrc = targetSrcList(pParse, pTriggerStep);
sqliteDeleteFrom(pParse, pSrc, sqliteExprDup(pTriggerStep->pWhere));
sqliteVdbeAddOp(pParse->pVdbe, OP_ListPop, 0, 0);
break;
}
default:
assert(0);
}
pParse->nTab = saveNTab;
pTriggerStep = pTriggerStep->pNext;
}
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 sqliteCodeRowTrigger(
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 TK_BEFORE, TK_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 * pTrigger;
TriggerStack * pTriggerStack;
assert(op == TK_UPDATE || op == TK_INSERT || op == TK_DELETE);
assert(tr_tm == TK_BEFORE || tr_tm == TK_AFTER );
assert(newIdx != -1 || oldIdx != -1);
pTrigger = pTab->pTrigger;
while( pTrigger ){
int fire_this = 0;
/* determine whether we should code this trigger */
if( pTrigger->op == op && pTrigger->tr_tm == tr_tm &&
pTrigger->foreach == TK_ROW ){
fire_this = 1;
pTriggerStack = pParse->trigStack;
while( pTriggerStack ){
if( pTriggerStack->pTrigger == pTrigger ){
fire_this = 0;
}
pTriggerStack = pTriggerStack->pNext;
}
if( op == TK_UPDATE && pTrigger->pColumns &&
!checkColumnOverLap(pTrigger->pColumns, pChanges) ){
fire_this = 0;
}
}
if( fire_this && (pTriggerStack = sqliteMalloc(sizeof(TriggerStack)))!=0 ){
int endTrigger;
SrcList dummyTablist;
Expr * whenExpr;
AuthContext sContext;
dummyTablist.nSrc = 0;
/* Push an entry on to the trigger stack */
pTriggerStack->pTrigger = pTrigger;
pTriggerStack->newIdx = newIdx;
pTriggerStack->oldIdx = oldIdx;
pTriggerStack->pTab = pTab;
pTriggerStack->pNext = pParse->trigStack;
pTriggerStack->ignoreJump = ignoreJump;
pParse->trigStack = pTriggerStack;
sqliteAuthContextPush(pParse, &sContext, pTrigger->name);
/* code the WHEN clause */
endTrigger = sqliteVdbeMakeLabel(pParse->pVdbe);
whenExpr = sqliteExprDup(pTrigger->pWhen);
if( sqliteExprResolveIds(pParse, &dummyTablist, 0, whenExpr) ){
pParse->trigStack = pParse->trigStack->pNext;
sqliteFree(pTriggerStack);
sqliteExprDelete(whenExpr);
return 1;
}
sqliteExprIfFalse(pParse, whenExpr, endTrigger, 1);
sqliteExprDelete(whenExpr);
sqliteVdbeAddOp(pParse->pVdbe, OP_ContextPush, 0, 0);
codeTriggerProgram(pParse, pTrigger->step_list, orconf);
sqliteVdbeAddOp(pParse->pVdbe, OP_ContextPop, 0, 0);
/* Pop the entry off the trigger stack */
pParse->trigStack = pParse->trigStack->pNext;
sqliteAuthContextPop(&sContext);
sqliteFree(pTriggerStack);
sqliteVdbeResolveLabel(pParse->pVdbe, endTrigger);
}
pTrigger = pTrigger->pNext;
}
return 0;
}