/*-------------------------------------------------------------------------
*
* rewriteHandler.c
+ * Primary module of query rewriter.
*
* Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- *
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteHandler.c,v 1.94 2001/06/12 18:54:22 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteHandler.c,v 1.95 2001/06/13 18:56:30 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "parser/parse_target.h"
#include "parser/parsetree.h"
#include "parser/parse_type.h"
+#include "rewrite/rewriteHandler.h"
#include "rewrite/rewriteManip.h"
#include "utils/lsyscache.h"
-static RewriteInfo *gatherRewriteMeta(Query *parsetree,
- Query *rule_action,
- Node *rule_qual,
- int rt_index,
- CmdType event,
- bool instead_flag);
+static Query *rewriteRuleAction(Query *parsetree,
+ Query *rule_action,
+ Node *rule_qual,
+ int rt_index,
+ CmdType event);
static List *adjustJoinTreeList(Query *parsetree, bool removert, int rt_index);
static void markQueryForUpdate(Query *qry, bool skipOldNew);
static List *matchLocks(CmdType event, RuleLock *rulelocks,
/*
- * gatherRewriteMeta -
- * Gather meta information about parsetree, and rule. Fix rule body
- * and qualifier so that they can be mixed with the parsetree and
- * maintain semantic validity
+ * rewriteRuleAction -
+ * Rewrite the rule action with appropriate qualifiers (taken from
+ * the triggering query).
*/
-static RewriteInfo *
-gatherRewriteMeta(Query *parsetree,
+static Query *
+rewriteRuleAction(Query *parsetree,
Query *rule_action,
Node *rule_qual,
int rt_index,
- CmdType event,
- bool instead_flag)
+ CmdType event)
{
- RewriteInfo *info;
+ int current_varno,
+ new_varno;
+ int rt_length;
Query *sub_action;
Query **sub_action_ptr;
- int rt_length;
- info = (RewriteInfo *) palloc(sizeof(RewriteInfo));
- info->rt_index = rt_index;
- info->event = event;
- info->instead_flag = instead_flag;
- info->rule_action = (Query *) copyObject(rule_action);
- info->rule_qual = (Node *) copyObject(rule_qual);
- if (info->rule_action == NULL)
- {
- info->nothing = TRUE;
- return info;
- }
- info->nothing = FALSE;
- info->action = info->rule_action->commandType;
- info->current_varno = rt_index;
+ /*
+ * Make modifiable copies of rule action and qual (what we're passed
+ * are the stored versions in the relcache; don't touch 'em!).
+ */
+ rule_action = (Query *) copyObject(rule_action);
+ rule_qual = (Node *) copyObject(rule_qual);
+
+ current_varno = rt_index;
rt_length = length(parsetree->rtable);
- info->new_varno = PRS2_NEW_VARNO + rt_length;
+ new_varno = PRS2_NEW_VARNO + rt_length;
/*
* Adjust rule action and qual to offset its varnos, so that we can
* will be in the SELECT part, and we have to modify that rather than
* the top-level INSERT (kluge!).
*/
- sub_action = getInsertSelectQuery(info->rule_action, &sub_action_ptr);
+ sub_action = getInsertSelectQuery(rule_action, &sub_action_ptr);
OffsetVarNodes((Node *) sub_action, rt_length, 0);
- OffsetVarNodes(info->rule_qual, rt_length, 0);
+ OffsetVarNodes(rule_qual, rt_length, 0);
/* but references to *OLD* should point at original rt_index */
ChangeVarNodes((Node *) sub_action,
PRS2_OLD_VARNO + rt_length, rt_index, 0);
- ChangeVarNodes(info->rule_qual,
+ ChangeVarNodes(rule_qual,
PRS2_OLD_VARNO + rt_length, rt_index, 0);
/*
keeporig = (!rangeTableEntry_used((Node *) sub_action->jointree,
rt_index, 0)) &&
- (rangeTableEntry_used(info->rule_qual, rt_index, 0) ||
- rangeTableEntry_used(parsetree->jointree->quals, rt_index, 0));
+ (rangeTableEntry_used(rule_qual, rt_index, 0) ||
+ rangeTableEntry_used(parsetree->jointree->quals, rt_index, 0));
newjointree = adjustJoinTreeList(parsetree, !keeporig, rt_index);
sub_action->jointree->fromlist =
nconc(newjointree, sub_action->jointree->fromlist);
* We copy the qualifications of the parsetree to the action and vice
* versa. So force hasSubLinks if one of them has it. If this is not
* right, the flag will get cleared later, but we mustn't risk having
- * it not set when it needs to be.
+ * it not set when it needs to be. (XXX this should probably be handled
+ * by AddQual and friends, not here...)
*/
if (parsetree->hasSubLinks)
sub_action->hasSubLinks = TRUE;
* two queries one w/rule_qual, one w/NOT rule_qual. Also add user
* query qual onto rule action
*/
- AddQual(sub_action, info->rule_qual);
+ AddQual(sub_action, rule_qual);
AddQual(sub_action, parsetree->jointree->quals);
*
* KLUGE ALERT: since ResolveNew returns a mutated copy, we can't just
* apply it to sub_action; we have to remember to update the sublink
- * inside info->rule_action, too.
+ * inside rule_action, too.
*/
- if (info->event == CMD_INSERT || info->event == CMD_UPDATE)
+ if (event == CMD_INSERT || event == CMD_UPDATE)
{
sub_action = (Query *) ResolveNew((Node *) sub_action,
- info->new_varno,
+ new_varno,
0,
parsetree->targetList,
- info->event,
- info->current_varno);
+ event,
+ current_varno);
if (sub_action_ptr)
*sub_action_ptr = sub_action;
else
- info->rule_action = sub_action;
+ rule_action = sub_action;
}
- return info;
+ return rule_action;
}
/*
foreach(r, actions)
{
Query *rule_action = lfirst(r);
- RewriteInfo *info;
if (rule_action->commandType == CMD_NOTHING)
continue;
- info = gatherRewriteMeta(parsetree, rule_action, event_qual,
- rt_index, event, *instead_flag);
-
- /* handle escapable cases, or those handled by other code */
- if (info->nothing)
- {
- if (*instead_flag)
- return NIL;
- else
- continue;
- }
-
- results = lappend(results, info->rule_action);
+ rule_action = rewriteRuleAction(parsetree, rule_action,
+ event_qual, rt_index, event);
- pfree(info);
+ results = lappend(results, rule_action);
}
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