Postgres95 1.01 Distribution - Virgin Sources

2025-11-06 07:49:08 +03:00 · 1996-07-09 06:22:35 +00:00
commit d31084e9d1
868 changed files with 242656 additions and 0 deletions
--- a/src/backend/rewrite/locks.c
+++ b/src/backend/rewrite/locks.c
@@ -0,0 +1,131 @@
+/*-------------------------------------------------------------------------
+ *
+ * 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);
+}
+