Reimplement the linked list data structure used throughout the backend.

In the past, we used a 'Lispy' linked list implementation: a "list" was
merely a pointer to the head node of the list. The problem with that
design is that it makes lappend() and length() linear time. This patch
fixes that problem (and others) by maintaining a count of the list
length and a pointer to the tail node along with each head node pointer.
A "list" is now a pointer to a structure containing some meta-data
about the list; the head and tail pointers in that structure refer
to ListCell structures that maintain the actual linked list of nodes.

The function names of the list API have also been changed to, I hope,
be more logically consistent. By default, the old function names are
still available; they will be disabled-by-default once the rest of
the tree has been updated to use the new API names.

1 files changed, 16 insertions, 16 deletions

diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index e8ed4ce5cc4..5ee954ab4d6 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -26,7 +26,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/executor/execMain.c,v 1.231 2004/05/11 17:36:12 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/executor/execMain.c,v 1.232 2004/05/26 04:41:14 neilc Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -353,11 +353,11 @@ ExecutorRewind(QueryDesc *queryDesc)
 void
 ExecCheckRTPerms(List *rangeTable)
 {
-	List	   *lp;
+	ListCell   *l;
 
-	foreach(lp, rangeTable)
+	foreach(l, rangeTable)
 	{
-		RangeTblEntry *rte = lfirst(lp);
+		RangeTblEntry *rte = lfirst(l);
 
 		ExecCheckRTEPerms(rte);
 	}
@@ -427,7 +427,7 @@ ExecCheckRTEPerms(RangeTblEntry *rte)
 static void
 ExecCheckXactReadOnly(Query *parsetree)
 {
-	List	   *lp;
+	ListCell   *l;
 
 	/*
 	 * CREATE TABLE AS or SELECT INTO?
@@ -438,9 +438,9 @@ ExecCheckXactReadOnly(Query *parsetree)
 		goto fail;
 
 	/* Fail if write permissions are requested on any non-temp table */
-	foreach(lp, parsetree->rtable)
+	foreach(l, parsetree->rtable)
 	{
-		RangeTblEntry *rte = lfirst(lp);
+		RangeTblEntry *rte = lfirst(l);
 
 		if (rte->rtekind == RTE_SUBQUERY)
 		{
@@ -521,20 +521,20 @@ InitPlan(QueryDesc *queryDesc, bool explainOnly)
 			 * Multiple result relations (due to inheritance)
 			 * parseTree->resultRelations identifies them all
 			 */
-			ResultRelInfo *resultRelInfo;
+			ResultRelInfo	*resultRelInfo;
+			ListCell		*l;
 
 			numResultRelations = length(resultRelations);
 			resultRelInfos = (ResultRelInfo *)
 				palloc(numResultRelations * sizeof(ResultRelInfo));
 			resultRelInfo = resultRelInfos;
-			while (resultRelations != NIL)
+			foreach(l, resultRelations)
 			{
 				initResultRelInfo(resultRelInfo,
-								  lfirsti(resultRelations),
+								  lfirst_int(l),
 								  rangeTable,
 								  operation);
 				resultRelInfo++;
-				resultRelations = lnext(resultRelations);
 			}
 		}
 		else
@@ -586,7 +586,7 @@ InitPlan(QueryDesc *queryDesc, bool explainOnly)
 	estate->es_rowMark = NIL;
 	if (parseTree->rowMarks != NIL)
 	{
-		List	   *l;
+		ListCell   *l;
 
 		foreach(l, parseTree->rowMarks)
 		{
@@ -651,7 +651,7 @@ InitPlan(QueryDesc *queryDesc, bool explainOnly)
 	 */
 	{
 		bool		junk_filter_needed = false;
-		List	   *tlist;
+		ListCell   *tlist;
 
 		switch (operation)
 		{
@@ -950,7 +950,7 @@ ExecEndPlan(PlanState *planstate, EState *estate)
 {
 	ResultRelInfo *resultRelInfo;
 	int			i;
-	List	   *l;
+	ListCell   *l;
 
 	/*
 	 * shut down any PlanQual processing we were doing
@@ -1132,7 +1132,7 @@ lnext:	;
 			}
 			else if (estate->es_rowMark != NIL)
 			{
-				List	   *l;
+				ListCell   *l;
 
 		lmark:	;
 				foreach(l, estate->es_rowMark)
@@ -1785,7 +1785,7 @@ EvalPlanQual(EState *estate, Index rti, ItemPointer tid)
 		relation = estate->es_result_relation_info->ri_RelationDesc;
 	else
 	{
-		List	   *l;
+		ListCell   *l;
 
 		relation = NULL;
 		foreach(l, estate->es_rowMark)