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/*-------------------------------------------------------------------------
*
* locks.c--
*
* Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/rewrite/Attic/locks.c,v 1.1.1.1 1996/07/09 06:21:51 scrappy Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h" /* for oid defs */
#include "utils/elog.h" /* for elog */
#include "nodes/pg_list.h" /* lisp support package */
#include "nodes/parsenodes.h"
#include "nodes/primnodes.h" /* Var node def */
#include "utils/syscache.h" /* for SearchSysCache */
#include "rewrite/locks.h" /* for rewrite specific lock defns */
/*
* ThisLockWasTriggered
*
* walk the tree, if there we find a varnode,
* we check the varattno against the attnum
* if we find at least one such match, we return true
* otherwise, we return false
*/
bool
nodeThisLockWasTriggered(Node *node, int varno, AttrNumber attnum)
{
if (node==NULL)
return FALSE;
switch(nodeTag(node)) {
case T_Var:
{
Var *var = (Var *)node;
if (varno == var->varno &&
(attnum == var->varattno || attnum == -1))
return TRUE;
}
break;
case T_Expr:
{
Expr *expr = (Expr*)node;
return
nodeThisLockWasTriggered((Node*)expr->args, varno, attnum);
}
break;
case T_TargetEntry:
{
TargetEntry *tle = (TargetEntry *)node;
return
nodeThisLockWasTriggered(tle->expr, varno, attnum);
}
break;
case T_List:
{
List *l;
foreach(l, (List*)node) {
if (nodeThisLockWasTriggered(lfirst(l), varno, attnum))
return TRUE;
}
return FALSE;
}
break;
default:
break;
}
return (FALSE);
}
/*
* thisLockWasTriggered -
* walk the tree, if there we find a varnode, we check the varattno
* against the attnum if we find at least one such match, we return true
* otherwise, we return false
*/
static bool
thisLockWasTriggered(int varno,
AttrNumber attnum,
Query *parsetree)
{
return
(nodeThisLockWasTriggered(parsetree->qual, varno, attnum) ||
nodeThisLockWasTriggered((Node*)parsetree->targetList,
varno, attnum));
}
/*
* matchLocks -
* match the list of locks and returns the matching rules
*/
List *
matchLocks(CmdType event,
RuleLock *rulelocks,
int varno,
Query *parsetree)
{
List *real_locks = NIL;
int nlocks;
int i;
Assert(rulelocks != NULL); /* we get called iff there is some lock */
Assert(parsetree != NULL);
if (parsetree->commandType != CMD_SELECT) {
if (parsetree->resultRelation != varno) {
return ( NULL );
}
}
nlocks = rulelocks->numLocks;
for (i = 0; i < nlocks; i++) {
RewriteRule *oneLock = rulelocks->rules[i];
if (oneLock->event == event) {
if (parsetree->commandType != CMD_SELECT ||
thisLockWasTriggered(varno,
oneLock->attrno,
parsetree)) {
real_locks = lappend(real_locks, oneLock);
}
}
}
return (real_locks);
}
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