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, 71 insertions, 115 deletions

diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index 91fb3b08343..21cef887922 100644
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -15,11 +15,13 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/copyfuncs.c,v 1.281 2004/05/10 22:44:44 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/copyfuncs.c,v 1.282 2004/05/26 04:41:18 neilc Exp $
  *
  *-------------------------------------------------------------------------
  */
 
+#define DISABLE_LIST_COMPAT
+
 #include "postgres.h"
 
 #include "nodes/parsenodes.h"
@@ -43,14 +45,6 @@
 #define COPY_NODE_FIELD(fldname) \
 	(newnode->fldname = copyObject(from->fldname))
 
-/* Copy a field that is a pointer to a list of integers */
-#define COPY_INTLIST_FIELD(fldname) \
-	(newnode->fldname = listCopy(from->fldname))
-
-/* Copy a field that is a pointer to a list of Oids */
-#define COPY_OIDLIST_FIELD(fldname) \
-	(newnode->fldname = listCopy(from->fldname))
-
 /* Copy a field that is a pointer to a Bitmapset */
 #define COPY_BITMAPSET_FIELD(fldname) \
 	(newnode->fldname = bms_copy(from->fldname))
@@ -68,46 +62,6 @@
 	} while (0)
 
 
-/*
- * listCopy
- *	  This copy function only copies the "cons-cells" of the list, not the
- *	  pointed-to objects.  (Use copyObject if you want a "deep" copy.)
- *
- *	  We also use this function for copying lists of integers and Oids,
- *	  which is notationally a bit ugly, but perfectly safe.
- *
- *	  Note that copyObject will surely coredump if applied to a list
- *	  of integers or Oids!
- */
-List *
-listCopy(List *list)
-{
-	List	   *newlist,
-			   *oldl,
-			   *newcell,
-			   *prev;
-
-	/* rather ugly coding for speed... */
-	if (list == NIL)
-		return NIL;
-
-	newcell = makeNode(List);
-	newcell->elem = list->elem;
-
-	newlist = prev = newcell;
-
-	foreach(oldl, lnext(list))
-	{
-		newcell = makeNode(List);
-		newcell->elem = oldl->elem;
-		prev->next = newcell;
-		prev = newcell;
-	}
-	prev->next = NIL;
-
-	return newlist;
-}
-
 /* ****************************************************************
  *					 plannodes.h copy functions
  * ****************************************************************
@@ -259,42 +213,12 @@ _copyIndexScan(IndexScan *from)
 	/*
 	 * copy remainder of node
 	 */
-	COPY_OIDLIST_FIELD(indxid);
+	COPY_NODE_FIELD(indxid);
 	COPY_NODE_FIELD(indxqual);
 	COPY_NODE_FIELD(indxqualorig);
-	/* this can become COPY_NODE_FIELD when intlists are normal objects: */
-	{
-		List	*newstrat = NIL;
-		List    *tmp;
-
-		foreach(tmp, from->indxstrategy)
-		{
-			newstrat = lappend(newstrat, listCopy(lfirst(tmp)));
-		}
-		newnode->indxstrategy = newstrat;
-	}
-	/* this can become COPY_NODE_FIELD when OID lists are normal objects: */
-	{
-		List	*newsubtype = NIL;
-		List    *tmp;
-
-		foreach(tmp, from->indxsubtype)
-		{
-			newsubtype = lappend(newsubtype, listCopy(lfirst(tmp)));
-		}
-		newnode->indxsubtype = newsubtype;
-	}
-	/* this can become COPY_NODE_FIELD when intlists are normal objects: */
-	{
-		List	*newstrat = NIL;
-		List    *tmp;
-
-		foreach(tmp, from->indxlossy)
-		{
-			newstrat = lappend(newstrat, listCopy(lfirst(tmp)));
-		}
-		newnode->indxlossy = newstrat;
-	}
+	COPY_NODE_FIELD(indxstrategy);
+	COPY_NODE_FIELD(indxsubtype);
+	COPY_NODE_FIELD(indxlossy);
 	COPY_SCALAR_FIELD(indxorderdir);
 
 	return newnode;
@@ -876,7 +800,7 @@ _copySubLink(SubLink *from)
 	COPY_SCALAR_FIELD(useOr);
 	COPY_NODE_FIELD(lefthand);
 	COPY_NODE_FIELD(operName);
-	COPY_OIDLIST_FIELD(operOids);
+	COPY_NODE_FIELD(operOids);
 	COPY_NODE_FIELD(subselect);
 
 	return newnode;
@@ -893,14 +817,14 @@ _copySubPlan(SubPlan *from)
 	COPY_SCALAR_FIELD(subLinkType);
 	COPY_SCALAR_FIELD(useOr);
 	COPY_NODE_FIELD(exprs);
-	COPY_INTLIST_FIELD(paramIds);
+	COPY_NODE_FIELD(paramIds);
 	COPY_NODE_FIELD(plan);
 	COPY_SCALAR_FIELD(plan_id);
 	COPY_NODE_FIELD(rtable);
 	COPY_SCALAR_FIELD(useHashTable);
 	COPY_SCALAR_FIELD(unknownEqFalse);
-	COPY_INTLIST_FIELD(setParam);
-	COPY_INTLIST_FIELD(parParam);
+	COPY_NODE_FIELD(setParam);
+	COPY_NODE_FIELD(parParam);
 	COPY_NODE_FIELD(args);
 
 	return newnode;
@@ -1582,7 +1506,7 @@ _copyQuery(Query *from)
 	COPY_SCALAR_FIELD(hasSubLinks);
 	COPY_NODE_FIELD(rtable);
 	COPY_NODE_FIELD(jointree);
-	COPY_INTLIST_FIELD(rowMarks);
+	COPY_NODE_FIELD(rowMarks);
 	COPY_NODE_FIELD(targetList);
 	COPY_NODE_FIELD(groupClause);
 	COPY_NODE_FIELD(havingQual);
@@ -1591,7 +1515,7 @@ _copyQuery(Query *from)
 	COPY_NODE_FIELD(limitOffset);
 	COPY_NODE_FIELD(limitCount);
 	COPY_NODE_FIELD(setOperations);
-	COPY_INTLIST_FIELD(resultRelations);
+	COPY_NODE_FIELD(resultRelations);
 	COPY_NODE_FIELD(in_info_list);
 	COPY_SCALAR_FIELD(hasJoinRTEs);
 
@@ -1679,7 +1603,7 @@ _copySetOperationStmt(SetOperationStmt *from)
 	COPY_SCALAR_FIELD(all);
 	COPY_NODE_FIELD(larg);
 	COPY_NODE_FIELD(rarg);
-	COPY_OIDLIST_FIELD(colTypes);
+	COPY_NODE_FIELD(colTypes);
 
 	return newnode;
 }
@@ -1731,7 +1655,7 @@ _copyGrantStmt(GrantStmt *from)
 	COPY_SCALAR_FIELD(is_grant);
 	COPY_SCALAR_FIELD(objtype);
 	COPY_NODE_FIELD(objects);
-	COPY_INTLIST_FIELD(privileges);
+	COPY_NODE_FIELD(privileges);
 	COPY_NODE_FIELD(grantees);
 	COPY_SCALAR_FIELD(grant_option);
 	COPY_SCALAR_FIELD(behavior);
@@ -2477,7 +2401,7 @@ _copyPrepareStmt(PrepareStmt *from)
 
 	COPY_STRING_FIELD(name);
 	COPY_NODE_FIELD(argtypes);
-	COPY_OIDLIST_FIELD(argtype_oids);
+	COPY_NODE_FIELD(argtype_oids);
 	COPY_NODE_FIELD(query);
 
 	return newnode;
@@ -2511,6 +2435,47 @@ _copyDeallocateStmt(DeallocateStmt *from)
  * ****************************************************************
  */
 
+/*
+ * Perform a deep copy of the specified list, using copyObject(). The
+ * list MUST be of type T_List; T_IntList and T_OidList nodes don't
+ * need deep copies, so they should be copied via list_copy()
+ */
+#define COPY_NODE_CELL(new, old)					\
+	(new) = (ListCell *) palloc(sizeof(ListCell));	\
+	lfirst(new) = copyObject(lfirst(old));
+
+static List *
+_copyList(List *from)
+{
+	List		*new;
+	ListCell	*curr_old;
+	ListCell	*prev_new;
+
+	Assert(list_length(from) >= 1);
+
+	new = makeNode(List);
+	new->length = from->length;
+
+	COPY_NODE_CELL(new->head, from->head);
+	prev_new = new->head;
+	curr_old = lnext(from->head);
+
+	while (curr_old)
+	{
+		COPY_NODE_CELL(prev_new->next, curr_old);
+		prev_new = prev_new->next;
+		curr_old = curr_old->next;
+	}
+	prev_new->next = NULL;
+	new->tail = prev_new;
+
+	return new;
+}
+
+/* ****************************************************************
+ *					value.h copy functions
+ * ****************************************************************
+ */
 static Value *
 _copyValue(Value *from)
 {
@@ -2752,30 +2717,21 @@ copyObject(void *from)
 		case T_Null:
 			retval = _copyValue(from);
 			break;
+
+			/*
+			 * LIST NODES
+			 */
 		case T_List:
-			{
-				List	   *list = from,
-						   *oldl,
-						   *newcell,
-						   *prev;
-
-				/* rather ugly coding for speed... */
-				/* Note the input list cannot be NIL if we got here. */
-				newcell = makeNode(List);
-				lfirst(newcell) = copyObject(lfirst(list));
-
-				retval = (void *) newcell;
-				prev = newcell;
-
-				foreach(oldl, lnext(list))
-				{
-					newcell = makeNode(List);
-					lfirst(newcell) = copyObject(lfirst(oldl));
-					prev->next = newcell;
-					prev = newcell;
-				}
-				prev->next = NIL;
-			}
+			retval = _copyList(from);
+			break;
+			/*
+			 * Lists of integers and OIDs don't need to be
+			 * deep-copied, so we perform a shallow copy via
+			 * list_copy()
+			 */
+		case T_IntList:
+		case T_OidList:
+			retval = list_copy(from);
 			break;
 
 			/*