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, 44 insertions, 90 deletions

diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index e919a851940..f9e3f7fbcb6 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/outfuncs.c,v 1.236 2004/05/10 22:44:44 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/outfuncs.c,v 1.237 2004/05/26 04:41:19 neilc Exp $
  *
  * NOTES
  *	  Every node type that can appear in stored rules' parsetrees *must*
@@ -19,6 +19,8 @@
  *
  *-------------------------------------------------------------------------
  */
+#define DISABLE_LIST_COMPAT
+
 #include "postgres.h"
 
 #include <ctype.h>
@@ -85,16 +87,6 @@
 	(appendStringInfo(str, " :" CppAsString(fldname) " "), \
 	 _outNode(str, node->fldname))
 
-/* Write an integer-list field */
-#define WRITE_INTLIST_FIELD(fldname) \
-	(appendStringInfo(str, " :" CppAsString(fldname) " "), \
-	 _outIntList(str, node->fldname))
-
-/* Write an OID-list field */
-#define WRITE_OIDLIST_FIELD(fldname) \
-	(appendStringInfo(str, " :" CppAsString(fldname) " "), \
-	 _outOidList(str, node->fldname))
-
 /* Write a bitmapset field */
 #define WRITE_BITMAPSET_FIELD(fldname) \
 	(appendStringInfo(str, " :" CppAsString(fldname) " "), \
@@ -145,35 +137,40 @@ _outToken(StringInfo str, char *s)
 	}
 }
 
-/*
- * _outIntList -
- *	   converts a List of integers
- */
 static void
-_outIntList(StringInfo str, List *list)
+_outList(StringInfo str, List *node)
 {
-	List	   *l;
+	ListCell *lc;
 
 	appendStringInfoChar(str, '(');
-	appendStringInfoChar(str, 'i');
-	foreach(l, list)
-		appendStringInfo(str, " %d", lfirsti(l));
-	appendStringInfoChar(str, ')');
-}
 
-/*
- * _outOidList -
- *	   converts a List of OIDs
- */
-static void
-_outOidList(StringInfo str, List *list)
-{
-	List	   *l;
+	if (IsA(node, IntList))
+		appendStringInfoChar(str, 'i');
+	else if (IsA(node, OidList))
+		appendStringInfoChar(str, 'o');
+
+	foreach (lc, node)
+	{
+		/*
+		 * For the sake of backward compatibility, we emit a slightly
+		 * different whitespace format for lists of nodes vs. other
+		 * types of lists. XXX: is this necessary?
+		 */
+		if (IsA(node, List))
+		{
+			_outNode(str, lfirst(lc));
+			if (lnext(lc))
+				appendStringInfoChar(str, ' ');
+		}
+		else if (IsA(node, IntList))
+			appendStringInfo(str, " %d", lfirst_int(lc));
+		else if (IsA(node, OidList))
+			appendStringInfo(str, " %u", lfirst_oid(lc));
+		else
+ 			elog(ERROR, "unrecognized list node type: %d",
+ 				 (int) node->type);
+	}
 
-	appendStringInfoChar(str, '(');
-	appendStringInfoChar(str, 'o');
-	foreach(l, list)
-		appendStringInfo(str, " %u", lfirsto(l));
 	appendStringInfoChar(str, ')');
 }
 
@@ -336,39 +333,12 @@ _outIndexScan(StringInfo str, IndexScan *node)
 
 	_outScanInfo(str, (Scan *) node);
 
-	WRITE_OIDLIST_FIELD(indxid);
+	WRITE_NODE_FIELD(indxid);
 	WRITE_NODE_FIELD(indxqual);
 	WRITE_NODE_FIELD(indxqualorig);
-	/* this can become WRITE_NODE_FIELD when intlists are normal objects: */
-	{
-		List    *tmp;
-
-		appendStringInfo(str, " :indxstrategy ");
-		foreach(tmp, node->indxstrategy)
-		{
-			_outIntList(str, lfirst(tmp));
-		}
-	}
-	/* this can become WRITE_NODE_FIELD when OID lists are normal objects: */
-	{
-		List    *tmp;
-
-		appendStringInfo(str, " :indxsubtype ");
-		foreach(tmp, node->indxsubtype)
-		{
-			_outOidList(str, lfirst(tmp));
-		}
-	}
-	/* this can become WRITE_NODE_FIELD when intlists are normal objects: */
-	{
-		List    *tmp;
-
-		appendStringInfo(str, " :indxlossy ");
-		foreach(tmp, node->indxlossy)
-		{
-			_outIntList(str, lfirst(tmp));
-		}
-	}
+	WRITE_NODE_FIELD(indxstrategy);
+	WRITE_NODE_FIELD(indxsubtype);
+	WRITE_NODE_FIELD(indxlossy);
 	WRITE_ENUM_FIELD(indxorderdir, ScanDirection);
 }
 
@@ -743,7 +713,7 @@ _outSubLink(StringInfo str, SubLink *node)
 	WRITE_BOOL_FIELD(useOr);
 	WRITE_NODE_FIELD(lefthand);
 	WRITE_NODE_FIELD(operName);
-	WRITE_OIDLIST_FIELD(operOids);
+	WRITE_NODE_FIELD(operOids);
 	WRITE_NODE_FIELD(subselect);
 }
 
@@ -755,14 +725,14 @@ _outSubPlan(StringInfo str, SubPlan *node)
 	WRITE_ENUM_FIELD(subLinkType, SubLinkType);
 	WRITE_BOOL_FIELD(useOr);
 	WRITE_NODE_FIELD(exprs);
-	WRITE_INTLIST_FIELD(paramIds);
+	WRITE_NODE_FIELD(paramIds);
 	WRITE_NODE_FIELD(plan);
 	WRITE_INT_FIELD(plan_id);
 	WRITE_NODE_FIELD(rtable);
 	WRITE_BOOL_FIELD(useHashTable);
 	WRITE_BOOL_FIELD(unknownEqFalse);
-	WRITE_INTLIST_FIELD(setParam);
-	WRITE_INTLIST_FIELD(parParam);
+	WRITE_NODE_FIELD(setParam);
+	WRITE_NODE_FIELD(parParam);
 	WRITE_NODE_FIELD(args);
 }
 
@@ -1302,7 +1272,7 @@ _outQuery(StringInfo str, Query *node)
 	WRITE_BOOL_FIELD(hasSubLinks);
 	WRITE_NODE_FIELD(rtable);
 	WRITE_NODE_FIELD(jointree);
-	WRITE_INTLIST_FIELD(rowMarks);
+	WRITE_NODE_FIELD(rowMarks);
 	WRITE_NODE_FIELD(targetList);
 	WRITE_NODE_FIELD(groupClause);
 	WRITE_NODE_FIELD(havingQual);
@@ -1311,7 +1281,7 @@ _outQuery(StringInfo str, Query *node)
 	WRITE_NODE_FIELD(limitOffset);
 	WRITE_NODE_FIELD(limitCount);
 	WRITE_NODE_FIELD(setOperations);
-	WRITE_INTLIST_FIELD(resultRelations);
+	WRITE_NODE_FIELD(resultRelations);
 
 	/* planner-internal fields are not written out */
 }
@@ -1343,7 +1313,7 @@ _outSetOperationStmt(StringInfo str, SetOperationStmt *node)
 	WRITE_BOOL_FIELD(all);
 	WRITE_NODE_FIELD(larg);
 	WRITE_NODE_FIELD(rarg);
-	WRITE_OIDLIST_FIELD(colTypes);
+	WRITE_NODE_FIELD(colTypes);
 }
 
 static void
@@ -1444,7 +1414,6 @@ _outValue(StringInfo str, Value *value)
 			appendStringInfo(str, "%ld", value->val.ival);
 			break;
 		case T_Float:
-
 			/*
 			 * We assume the value is a valid numeric literal and so does
 			 * not need quoting.
@@ -1572,24 +1541,9 @@ static void
 _outNode(StringInfo str, void *obj)
 {
 	if (obj == NULL)
-	{
 		appendStringInfo(str, "<>");
-		return;
-	}
-
-	if (IsA(obj, List))
-	{
-		List	   *l;
-
-		appendStringInfoChar(str, '(');
-		foreach(l, (List *) obj)
-		{
-			_outNode(str, lfirst(l));
-			if (lnext(l))
-				appendStringInfoChar(str, ' ');
-		}
-		appendStringInfoChar(str, ')');
-	}
+	else if (IsA(obj, List) || IsA(obj, IntList) || IsA(obj, OidList))
+		_outList(str, obj);
 	else if (IsA(obj, Integer) ||
 			 IsA(obj, Float) ||
 			 IsA(obj, String) ||