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, 6 insertions, 6 deletions

diff --git a/src/backend/commands/opclasscmds.c b/src/backend/commands/opclasscmds.c
index d3551a7349f..db5c2ccabc9 100644
--- a/src/backend/commands/opclasscmds.c
+++ b/src/backend/commands/opclasscmds.c
@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/opclasscmds.c,v 1.24 2003/11/29 19:51:47 pgsql Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/opclasscmds.c,v 1.25 2004/05/26 04:41:11 neilc Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -77,7 +77,7 @@ DefineOpClass(CreateOpClassStmt *stmt)
 				numProcs;		/* amsupport value */
 	List	   *operators;		/* OpClassMember list for operators */
 	List	   *procedures;		/* OpClassMember list for support procs */
-	List	   *l;
+	ListCell   *l;
 	Relation	rel;
 	HeapTuple	tup;
 	Datum		values[Natts_pg_opclass];
@@ -168,7 +168,7 @@ DefineOpClass(CreateOpClassStmt *stmt)
 									item->number, numOperators)));
 				if (item->args != NIL)
 				{
-					TypeName   *typeName1 = (TypeName *) lfirst(item->args);
+					TypeName   *typeName1 = (TypeName *) linitial(item->args);
 					TypeName   *typeName2 = (TypeName *) lsecond(item->args);
 
 					operOid = LookupOperNameTypeNames(item->name,
@@ -506,7 +506,7 @@ assignProcSubtype(Oid amoid, Oid typeoid, Oid procOid)
 static void
 addClassMember(List **list, OpClassMember *member, bool isProc)
 {
-	List	   *l;
+	ListCell   *l;
 
 	foreach(l, *list)
 	{
@@ -540,7 +540,7 @@ storeOperators(Oid opclassoid, List *operators)
 	Datum		values[Natts_pg_amop];
 	char		nulls[Natts_pg_amop];
 	HeapTuple	tup;
-	List	   *l;
+	ListCell   *l;
 	int			i;
 
 	rel = heap_openr(AccessMethodOperatorRelationName, RowExclusiveLock);
@@ -584,7 +584,7 @@ storeProcedures(Oid opclassoid, List *procedures)
 	Datum		values[Natts_pg_amproc];
 	char		nulls[Natts_pg_amproc];
 	HeapTuple	tup;
-	List	   *l;
+	ListCell   *l;
 	int			i;
 
 	rel = heap_openr(AccessMethodProcedureRelationName, RowExclusiveLock);