/*
** 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.
*/
SQLITE_PRIVATE 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 = 0;
Trigger *p;
if( (pParse->db->flags & SQLITE_EnableTrigger)!=0 ){
pList = sqlite3TriggerList(pParse, pTab);
}
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);
}
/*
** Triggers may access values stored in the old.* or new.* pseudo-table.
** This function returns a 32-bit bitmask indicating which columns of the
** old.* or new.* tables actually are used by triggers. This information
** may be used by the caller, for example, to avoid having to load the entire
** old.* record into memory when executing an UPDATE or DELETE command.
**
** Bit 0 of the returned mask is set if the left-most column of the
** table may be accessed using an [old|new].<col> reference. Bit 1 is set if
** the second leftmost column value is required, and so on. If there
** are more than 32 columns in the table, and at least one of the columns
** with an index greater than 32 may be accessed, 0xffffffff is returned.
**
** It is not possible to determine if the old.rowid or new.rowid column is
** accessed by triggers. The caller must always assume that it is.
**
** Parameter isNew must be either 1 or 0. If it is 0, then the mask returned
** applies to the old.* table. If 1, the new.* table.
**
** Parameter tr_tm must be a mask with one or both of the TRIGGER_BEFORE
** and TRIGGER_AFTER bits set. Values accessed by BEFORE triggers are only
** included in the returned mask if the TRIGGER_BEFORE bit is set in the
** tr_tm parameter. Similarly, values accessed by AFTER triggers are only
** included in the returned mask if the TRIGGER_AFTER bit is set in tr_tm.
*/
SQLITE_PRIVATE u32 sqlite3TriggerColmask(
Parse *pParse, /* Parse context */
Trigger *pTrigger, /* List of triggers on table pTab */
ExprList *pChanges, /* Changes list for any UPDATE OF triggers */
int isNew, /* 1 for new.* ref mask, 0 for old.* ref mask */
int tr_tm, /* Mask of TRIGGER_BEFORE|TRIGGER_AFTER */
Table *pTab, /* The table to code triggers from */
int orconf /* Default ON CONFLICT policy for trigger steps */
){
const int op = pChanges ? TK_UPDATE : TK_DELETE;
u32 mask = 0;
Trigger *p;
assert( isNew==1 || isNew==0 );
for(p=pTrigger; p; p=p->pNext){
if( p->op==op && (tr_tm&p->tr_tm)
&& checkColumnOverlap(p->pColumns,pChanges)
){
TriggerPrg *pPrg;
pPrg = getRowTrigger(pParse, p, pTab, orconf);
if( pPrg ){
mask |= pPrg->aColmask[isNew];
}
}
}
return mask;
}
/*
** This is called to code the required FOR EACH ROW triggers for an operation
** on table pTab. The operation to code triggers for (INSERT, UPDATE or DELETE)
** is given by the op parameter. The tr_tm parameter determines whether the
** BEFORE or AFTER triggers are coded. If the operation is an UPDATE, then
** parameter pChanges is passed the list of columns being modified.
**
** If there are no triggers that fire at the specified time for the specified
** operation on pTab, this function is a no-op.
**
** The reg argument is the address of the first in an array of registers
** that contain the values substituted for the new.* and old.* references
** in the trigger program. If N is the number of columns in table pTab
** (a copy of pTab->nCol), then registers are populated as follows:
**
** Register Contains
** ------------------------------------------------------
** reg+0 OLD.rowid
** reg+1 OLD.* value of left-most column of pTab
** ... ...
** reg+N OLD.* value of right-most column of pTab
** reg+N+1 NEW.rowid
** reg+N+2 OLD.* value of left-most column of pTab
** ... ...
** reg+N+N+1 NEW.* value of right-most column of pTab
**
** For ON DELETE triggers, the registers containing the NEW.* values will
** never be accessed by the trigger program, so they are not allocated or
** populated by the caller (there is no data to populate them with anyway).
** Similarly, for ON INSERT triggers the values stored in the OLD.* registers
** are never accessed, and so are not allocated by the caller. So, for an
** ON INSERT trigger, the value passed to this function as parameter reg
** is not a readable register, although registers (reg+N) through
** (reg+N+N+1) are.
**
** Parameter orconf is the default conflict resolution algorithm for the
** trigger program to use (REPLACE, IGNORE etc.). Parameter ignoreJump
** is the instruction that control should jump to if a trigger program
** raises an IGNORE exception.
*/
SQLITE_PRIVATE void 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 reg, /* The first in an array of registers (see above) */
int orconf, /* ON CONFLICT policy */
int ignoreJump /* Instruction to jump to for RAISE(IGNORE) */
){
Trigger *p; /* Used to iterate through pTrigger list */
assert( op==TK_UPDATE || op==TK_INSERT || op==TK_DELETE );
assert( tr_tm==TRIGGER_BEFORE || tr_tm==TRIGGER_AFTER );
assert( (op==TK_UPDATE)==(pChanges!=0) );
for(p=pTrigger; p; p=p->pNext){
/* 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==pParse->db->aDb[1].pSchema );
/* Determine whether we should code this trigger */
if( p->op==op
&& p->tr_tm==tr_tm
&& checkColumnOverlap(p->pColumns, pChanges)
){
sqlite3CodeRowTriggerDirect(pParse, p, pTab, reg, orconf, ignoreJump);
}
}
}
/*
** 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);
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;
}
