/*
**
** 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.
**
*************************************************************************
**
**
** $Id: trigger.c,v 1.143 2009/08/10 03:57:58 shane Exp $
*/
#include "sqliteInt.h"
#ifndef SQLITE_OMIT_TRIGGER
/*
** Delete a linked list of TriggerStep structures.
*/
void sqlite3DeleteTriggerStep(sqlite3 *db, TriggerStep *pTriggerStep){
while( pTriggerStep ){
TriggerStep * pTmp = pTriggerStep;
pTriggerStep = pTriggerStep->pNext;
sqlite3ExprDelete(db, pTmp->pWhere);
sqlite3ExprListDelete(db, pTmp->pExprList);
sqlite3SelectDelete(db, pTmp->pSelect);
sqlite3IdListDelete(db, pTmp->pIdList);
sqlite3DbFree(db, pTmp);
}
}
/*
** Given table pTab, return a list of all the triggers attached to
** the table. The list is connected by Trigger.pNext pointers.
**
** All of the triggers on pTab that are in the same database as pTab
** are already attached to pTab->pTrigger. But there might be additional
** triggers on pTab in the TEMP schema. This routine prepends all
** TEMP triggers on pTab to the beginning of the pTab->pTrigger list
** and returns the combined list.
**
** To state it another way: This routine returns a list of all triggers
** that fire off of pTab. The list will include any TEMP triggers on
** pTab as well as the triggers lised in pTab->pTrigger.
*/
Trigger *sqlite3TriggerList(Parse *pParse, Table *pTab){
Schema * const pTmpSchema = pParse->db->aDb[1].pSchema;
Trigger *pList = 0; /* List of triggers to return */
if( pTmpSchema!=pTab->pSchema ){
HashElem *p;
for(p=sqliteHashFirst(&pTmpSchema->trigHash); p; p=sqliteHashNext(p)){
Trigger *pTrig = (Trigger *)sqliteHashData(p);
if( pTrig->pTabSchema==pTab->pSchema
&& 0==sqlite3StrICmp(pTrig->table, pTab->zName)
){
pTrig->pNext = (pList ? pList : pTab->pTrigger);
pList = pTrig;
}
}
}
return (pList ? pList : pTab->pTrigger);
}
/*
** 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; /* The new trigger */
Table *pTab; /* Table that the trigger fires off of */
char *zName = 0; /* Name of the trigger */
sqlite3 *db = pParse->db; /* The database connection */
int iDb; /* The database to store the trigger in */
Token *pName; /* The unqualified db name */
DbFixer sFix; /* State vector for the DB fixer */
int iTabDb; /* Index of the database holding pTab */
assert( pName1!=0 ); /* pName1->z might be NULL, but not pName1 itself */
assert( pName2!=0 );
assert( op==TK_INSERT || op==TK_UPDATE || op==TK_DELETE );
assert( op>0 && op<0xff );
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. */
if( db->init.iDb==1 ){
/* Ticket #3810.
** Normally, whenever a table is dropped, all associated triggers are
** dropped too. But if a TEMP trigger is created on a non-TEMP table
** and the table is dropped by a different database connection, the
** trigger is not visible to the database connection that does the
** drop so the trigger cannot be dropped. This results in an
** "orphaned trigger" - a trigger whose associated table is missing.
*/
db->init.orphanTrigger = 1;
}
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, sqlite3Strlen30(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 = (u8)op;
pTrigger->tr_tm = tr_tm==TK_BEFORE ? TRIGGER_BEFORE : TRIGGER_AFTER;
pTrigger->pWhen = sqlite3ExprDup(db, pWhen, EXPRDUP_REDUCE);
pTrigger->pColumns = sqlite3IdListDup(db, pColumns);
assert( pParse->pNewTrigger==0 );
pParse->pNewTrigger = pTrigger;
trigger_cleanup:
sqlite3DbFree(db, zName);
sqlite3SrcListDelete(db, pTableName);
sqlite3IdListDelete(db, pColumns);
sqlite3ExprDelete(db, pWhen);
if( !pParse->pNewTrigger ){
sqlite3DeleteTrigger(db, 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 = pParse->pNewTrigger; /* Trigger being finished */
char *zName; /* Name of trigger */
sqlite3 *db = pParse->db; /* The database */
DbFixer sFix;
int iDb; /* Database containing the trigger */
Token nameToken; /* Trigger name for error reporting */
pTrig = pParse->pNewTrigger;
pParse->pNewTrigger = 0;
if( NEVER(pParse->nErr) || !pTrig ) goto triggerfinish_cleanup;
zName = pTrig->name;
iDb = sqlite3SchemaToIndex(pParse->db, pTrig->pSchema);
pTrig->step_list = pStepList;
while( pStepList ){
pStepList->pTrig = pTrig;
pStepList = pStepList->pNext;
}
nameToken.z = pTrig->name;
nameToken.n = sqlite3Strlen30(nameToken.z);
if( sqlite3FixInit(&sFix, pParse, iDb, "trigger", &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), zName,
pTrig->table, z);
sqlite3DbFree(db, z);
sqlite3ChangeCookie(pParse, iDb);
sqlite3VdbeAddOp4(v, OP_ParseSchema, iDb, 0, 0, sqlite3MPrintf(
db, "type='trigger' AND name='%q'", zName), P4_DYNAMIC
);
}
if( db->init.busy ){
Trigger *pLink = pTrig;
Hash *pHash = &db->aDb[iDb].pSchema->trigHash;
pTrig = sqlite3HashInsert(pHash, zName, sqlite3Strlen30(zName), pTrig);
if( pTrig ){
db->mallocFailed = 1;
}else if( pLink->pSchema==pLink->pTabSchema ){
Table *pTab;
int n = sqlite3Strlen30(pLink->table);
pTab = sqlite3HashFind(&pLink->pTabSchema->tblHash, pLink->table, n);
assert( pTab!=0 );
pLink->pNext = pTab->pTrigger;
pTab->pTrigger = pLink;
}
}
triggerfinish_cleanup:
sqlite3DeleteTrigger(db, pTrig);
assert( !pParse->pNewTrigger );
sqlite3DeleteTriggerStep(db, pStepList);
}
/*
** 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(db, pSelect);
return 0;
}
pTriggerStep->op = TK_SELECT;
pTriggerStep->pSelect = pSelect;
pTriggerStep->orconf = OE_Default;
return pTriggerStep;
}
/*
** Allocate space to hold a new trigger step. The allocated space
** holds both the TriggerStep object and the TriggerStep.target.z string.
**
** If an OOM error occurs, NULL is returned and db->mallocFailed is set.
*/
static TriggerStep *triggerStepAllocate(
sqlite3 *db, /* Database connection */
u8 op, /* Trigger opcode */
Token *pName /* The target name */
){
TriggerStep *pTriggerStep;
pTriggerStep = sqlite3DbMallocZero(db, sizeof(TriggerStep) + pName->n);
if( pTriggerStep ){
char *z = (char*)&pTriggerStep[1];
memcpy(z, pName->z, pName->n);
pTriggerStep->target.z = z;
pTriggerStep->target.n = pName->n;
pTriggerStep->op = op;
}
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 */
u8 orconf /* The conflict algorithm (OE_Abort, OE_Replace, etc.) */
){
TriggerStep *pTriggerStep;
assert(pEList == 0 || pSelect == 0);
assert(pEList != 0 || pSelect != 0 || db->mallocFailed);
pTriggerStep = triggerStepAllocate(db, TK_INSERT, pTableName);
if( pTriggerStep ){
pTriggerStep->pSelect = sqlite3SelectDup(db, pSelect, EXPRDUP_REDUCE);
pTriggerStep->pIdList = pColumn;
pTriggerStep->pExprList = sqlite3ExprListDup(db, pEList, EXPRDUP_REDUCE);
pTriggerStep->orconf = orconf;
}else{
sqlite3IdListDelete(db, pColumn);
}
sqlite3ExprListDelete(db, pEList);
sqlite3SelectDelete(db, 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 */
u8 orconf /* The conflict algorithm. (OE_Abort, OE_Ignore, etc) */
){
TriggerStep *pTriggerStep;
pTriggerStep = triggerStepAllocate(db, TK_UPDATE, pTableName);
if( pTriggerStep ){
pTriggerStep->pExprList = sqlite3ExprListDup(db, pEList, EXPRDUP_REDUCE);
pTriggerStep->pWhere = sqlite3ExprDup(db, pWhere, EXPRDUP_REDUCE);
pTriggerStep->orconf = orconf;
}
sqlite3ExprListDelete(db, pEList);
sqlite3ExprDelete(db, pWhere);
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;
pTriggerStep = triggerStepAllocate(db, TK_DELETE, pTableName);
if( pTriggerStep ){
pTriggerStep->pWhere = sqlite3ExprDup(db, pWhere, EXPRDUP_REDUCE);
pTriggerStep->orconf = OE_Default;
}
sqlite3ExprDelete(db, pWhere);
return pTriggerStep;
}
/*
** Recursively delete a Trigger structure
*/
void sqlite3DeleteTrigger(sqlite3 *db, Trigger *pTrigger){
if( pTrigger==0 ) return;
sqlite3DeleteTriggerStep(db, pTrigger->step_list);
sqlite3DbFree(db, pTrigger->name);
sqlite3DbFree(db, pTrigger->table);
sqlite3ExprDelete(db, pTrigger->pWhen);
sqlite3IdListDelete(db, pTrigger->pColumns);
sqlite3DbFree(db, 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 = sqlite3Strlen30(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(db, pName);
}
/*
** Return a pointer to the Table structure for the table that a trigger
** is set on.
*/
static Table *tableOfTrigger(Trigger *pTrigger){
int n = sqlite3Strlen30(pTrigger->table);
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);
if( pParse->nMem<3 ){
pParse->nMem = 3;
}
}
}
/*
** Remove a trigger from the hash tables of the sqlite* pointer.
*/
void sqlite3UnlinkAndDeleteTrigger(sqlite3 *db, int iDb, const char *zName){
Hash *pHash = &(db->aDb[iDb].pSchema->trigHash);
Trigger *pTrigger;
pTrigger = sqlite3HashInsert(pHash, zName, sqlite3Strlen30(zName), 0);
if( ALWAYS(pTrigger) ){
if( pTrigger->pSchema==pTrigger->pTabSchema ){
Table *pTab = tableOfTrigger(pTrigger);
Trigger **pp;
for(pp=&pTab->pTrigger; *pp!=pTrigger; pp=&((*pp)->pNext));
*pp = (*pp)->pNext;
}
sqlite3DeleteTrigger(db, 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==0 || NEVER(pEList==0) ) return 1;
for(e=0; e<pEList->nExpr; e++){
if( sqlite3IdListIndex(pIdList, pEList->a[e].zName)>=0 ) return 1;
}
return 0;
}
/*
** Return a list of all triggers on table pTab if there exists at least
** one trigger that must be fired when an operation of type 'op' is
** performed on the table, and, if that operation is an UPDATE, if at
** least one of the columns in pChanges is being modified.
*/
Trigger *sqlite3TriggersExist(
Parse *pParse, /* Parse context */
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 */
int *pMask /* OUT: Mask of TRIGGER_BEFORE|TRIGGER_AFTER */
){
int mask = 0;
Trigger *pList = sqlite3TriggerList(pParse, pTab);
Trigger *p;
assert( pList==0 || IsVirtual(pTab)==0 );
for(p=pList; p; p=p->pNext){
if( p->op==op && checkColumnOverlap(p->pColumns, pChanges) ){
mask |= p->tr_tm;
}
}
if( pMask ){
*pMask = mask;
}
return (mask ? pList : 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 */
){
int iDb; /* Index of the database to use */
SrcList *pSrc; /* SrcList to be returned */
pSrc = sqlite3SrcListAppend(pParse->db, 0, &pStep->target, 0);
if( pSrc ){
assert( pSrc->nSrc>0 );
assert( pSrc->a!=0 );
iDb = sqlite3SchemaToIndex(pParse->db, pStep->pTrig->pSchema);
if( iDb==0 || iDb>=2 ){
sqlite3 *db = pParse->db;
assert( iDb<pParse->db->nDb );
pSrc->a[pSrc->nSrc-1].zDatabase = sqlite3DbStrDup(db, db->aDb[iDb].zName);
}
}
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 ){
sqlite3ExprCacheClear(pParse);
orconf = (orconfin == OE_Default)?pTriggerStep->orconf:orconfin;
pParse->trigStack->orconf = orconf;
switch( pTriggerStep->op ){
case TK_UPDATE: {
SrcList *pSrc;
pSrc = targetSrcList(pParse, pTriggerStep);
sqlite3VdbeAddOp2(v, OP_ResetCount, 0, 0);
sqlite3Update(pParse, pSrc,
sqlite3ExprListDup(db, pTriggerStep->pExprList, 0),
sqlite3ExprDup(db, pTriggerStep->pWhere, 0), 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, 0),
sqlite3SelectDup(db, pTriggerStep->pSelect, 0),
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, 0));
sqlite3VdbeAddOp2(v, OP_ResetCount, 1, 0);
break;
}
default: assert( pTriggerStep->op==TK_SELECT ); {
Select *ss = sqlite3SelectDup(db, pTriggerStep->pSelect, 0);
if( ss ){
SelectDest dest;
sqlite3SelectDestInit(&dest, SRT_Discard, 0);
sqlite3Select(pParse, ss, &dest);
sqlite3SelectDelete(db, ss);
}
break;
}
}
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 */
Trigger *pTrigger, /* List of triggers on table pTab */
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=pTrigger; p; p=p->pNext){
int fire_this = 0;
/* Sanity checking: The schema for the trigger and for the table are
** always defined. The trigger must be in the same schema as the table
** or else it must be a TEMP trigger. */
assert( p->pSchema!=0 );
assert( p->pTabSchema!=0 );
assert( p->pSchema==p->pTabSchema || p->pSchema==db->aDb[1].pSchema );
/* Determine whether we should code this trigger */
if(
p->op==op &&
p->tr_tm==tr_tm &&
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, 0);
if( db->mallocFailed || sqlite3ResolveExprNames(&sNC, whenExpr) ){
pParse->trigStack = trigStackEntry.pNext;
sqlite3ExprDelete(db, whenExpr);
return 1;
}
sqlite3ExprIfFalse(pParse, whenExpr, endTrigger, SQLITE_JUMPIFNULL);
sqlite3ExprDelete(db, whenExpr);
sqlite3ExprCachePush(pParse);
codeTriggerProgram(pParse, p->step_list, orconf);
sqlite3ExprCachePop(pParse, 1);
/* 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) */