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