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, 15 insertions, 22 deletions

diff --git a/src/backend/nodes/readfuncs.c b/src/backend/nodes/readfuncs.c
index 253b5a3eafa..792a6156eb8 100644
--- a/src/backend/nodes/readfuncs.c
+++ b/src/backend/nodes/readfuncs.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/readfuncs.c,v 1.169 2004/05/10 22:44:44 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/readfuncs.c,v 1.170 2004/05/26 04:41:19 neilc Exp $
  *
  * NOTES
  *	  Path and Plan nodes do not have any readfuncs support, because we
@@ -18,6 +18,8 @@
  *
  *-------------------------------------------------------------------------
  */
+#define DISABLE_LIST_COMPAT
+
 #include "postgres.h"
 
 #include <math.h>
@@ -33,21 +35,22 @@
  * routine.
  */
 
-/* Declare appropriate local variables */
-#define READ_LOCALS(nodeTypeName) \
-	nodeTypeName *local_node = makeNode(nodeTypeName); \
-	char	   *token; \
-	int			length
+/* Macros for declaring appropriate local variables */
 
 /* A few guys need only local_node */
 #define READ_LOCALS_NO_FIELDS(nodeTypeName) \
 	nodeTypeName *local_node = makeNode(nodeTypeName)
 
 /* And a few guys need only the pg_strtok support fields */
-#define READ_TEMP_LOCALS() \
-	char	   *token; \
+#define READ_TEMP_LOCALS()	\
+	char	   *token;		\
 	int			length
 
+/* ... but most need both */
+#define READ_LOCALS(nodeTypeName)			\
+	READ_LOCALS_NO_FIELDS(nodeTypeName);	\
+	READ_TEMP_LOCALS()
+
 /* Read an integer field (anything written as ":fldname %d") */
 #define READ_INT_FIELD(fldname) \
 	token = pg_strtok(&length);		/* skip :fldname */ \
@@ -101,16 +104,6 @@
 	token = pg_strtok(&length);		/* skip :fldname */ \
 	local_node->fldname = nodeRead(NULL, 0)
 
-/* Read an integer-list field (XXX combine me with READ_NODE_FIELD) */
-#define READ_INTLIST_FIELD(fldname) \
-	token = pg_strtok(&length);		/* skip :fldname */ \
-	local_node->fldname = nodeRead(NULL, 0)
-
-/* Read an OID-list field (XXX combine me with READ_NODE_FIELD) */
-#define READ_OIDLIST_FIELD(fldname) \
-	token = pg_strtok(&length);		/* skip :fldname */ \
-	local_node->fldname = nodeRead(NULL, 0)
-
 /* Routine exit */
 #define READ_DONE() \
 	return local_node
@@ -153,7 +146,7 @@ _readQuery(void)
 	READ_BOOL_FIELD(hasSubLinks);
 	READ_NODE_FIELD(rtable);
 	READ_NODE_FIELD(jointree);
-	READ_INTLIST_FIELD(rowMarks);
+	READ_NODE_FIELD(rowMarks);
 	READ_NODE_FIELD(targetList);
 	READ_NODE_FIELD(groupClause);
 	READ_NODE_FIELD(havingQual);
@@ -162,7 +155,7 @@ _readQuery(void)
 	READ_NODE_FIELD(limitOffset);
 	READ_NODE_FIELD(limitCount);
 	READ_NODE_FIELD(setOperations);
-	READ_INTLIST_FIELD(resultRelations);
+	READ_NODE_FIELD(resultRelations);
 
 	/* planner-internal fields are left zero */
 
@@ -237,7 +230,7 @@ _readSetOperationStmt(void)
 	READ_BOOL_FIELD(all);
 	READ_NODE_FIELD(larg);
 	READ_NODE_FIELD(rarg);
-	READ_OIDLIST_FIELD(colTypes);
+	READ_NODE_FIELD(colTypes);
 
 	READ_DONE();
 }
@@ -526,7 +519,7 @@ _readSubLink(void)
 	READ_BOOL_FIELD(useOr);
 	READ_NODE_FIELD(lefthand);
 	READ_NODE_FIELD(operName);
-	READ_OIDLIST_FIELD(operOids);
+	READ_NODE_FIELD(operOids);
 	READ_NODE_FIELD(subselect);
 
 	READ_DONE();