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.

Author: Neil Conway

src/backend/access/common/printtup.c

@@ -9,7 +9,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/common/printtup.c,v 1.80 2004/01/07 18:56:23 neilc Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/common/printtup.c,v 1.81 2004/05/26 04:41:03 neilc Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -138,7 +138,7 @@ printtup_startup(DestReceiver *self, int operation, TupleDesc typeinfo)
 		List	   *targetlist;
 
 		if (portal->strategy == PORTAL_ONE_SELECT)
-			targetlist = ((Query *) lfirst(portal->parseTrees))->targetList;
+			targetlist = ((Query *) linitial(portal->parseTrees))->targetList;
 		else
 			targetlist = NIL;
 
@@ -176,6 +176,7 @@ SendRowDescriptionMessage(TupleDesc typeinfo, List *targetlist, int16 *formats)
 	int			proto = PG_PROTOCOL_MAJOR(FrontendProtocol);
 	int			i;
 	StringInfoData buf;
+	ListCell   *tlist_item = list_head(targetlist);
 
 	pq_beginmessage(&buf, 'T'); /* tuple descriptor message type */
 	pq_sendint(&buf, natts, 2); /* # of attrs in tuples */
@@ -191,16 +192,16 @@ SendRowDescriptionMessage(TupleDesc typeinfo, List *targetlist, int16 *formats)
 		if (proto >= 3)
 		{
 			/* Do we have a non-resjunk tlist item? */
-			while (targetlist &&
-				   ((TargetEntry *) lfirst(targetlist))->resdom->resjunk)
-				targetlist = lnext(targetlist);
-			if (targetlist)
+			while (tlist_item &&
+				   ((TargetEntry *) lfirst(tlist_item))->resdom->resjunk)
+				tlist_item = lnext(tlist_item);
+			if (tlist_item)
 			{
-				Resdom	   *res = ((TargetEntry *) lfirst(targetlist))->resdom;
+				Resdom	   *res = ((TargetEntry *) lfirst(tlist_item))->resdom;
 
 				pq_sendint(&buf, res->resorigtbl, 4);
 				pq_sendint(&buf, res->resorigcol, 2);
-				targetlist = lnext(targetlist);
+				tlist_item = lnext(tlist_item);
 			}
 			else
 			{

src/backend/access/common/tupdesc.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/common/tupdesc.c,v 1.102 2004/04/01 21:28:43 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/common/tupdesc.c,v 1.103 2004/05/26 04:41:03 neilc Exp $
  *
  * NOTES
  *	  some of the executor utility code such as "ExecTypeFromTL" should be
@@ -472,7 +472,7 @@ BuildDescForRelation(List *schema)
 {
 	int			natts;
 	AttrNumber	attnum;
-	List	   *p;
+	ListCell   *l;
 	TupleDesc	desc;
 	AttrDefault *attrdef = NULL;
 	TupleConstr *constr = (TupleConstr *) palloc0(sizeof(TupleConstr));
@@ -490,9 +490,9 @@ BuildDescForRelation(List *schema)
 
 	attnum = 0;
 
-	foreach(p, schema)
+	foreach(l, schema)
 	{
-		ColumnDef  *entry = lfirst(p);
+		ColumnDef  *entry = lfirst(l);
 
 		/*
 		 * for each entry in the list, get the name and type information
@@ -661,7 +661,7 @@ TypeGetTupleDesc(Oid typeoid, List *colaliases)
 					 errmsg("number of aliases does not match number of columns")));
 
 		/* OK, get the column alias */
-		attname = strVal(lfirst(colaliases));
+		attname = strVal(linitial(colaliases));
 
 		tupdesc = CreateTemplateTupleDesc(1, false);
 		TupleDescInitEntry(tupdesc,

src/backend/access/nbtree/nbtxlog.c

@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/nbtree/nbtxlog.c,v 1.10 2004/01/07 18:56:24 neilc Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/nbtree/nbtxlog.c,v 1.11 2004/05/26 04:41:05 neilc Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -59,7 +59,7 @@ forget_matching_split(Relation reln, RelFileNode node,
 	Page		page;
 	BTItem		btitem;
 	BlockNumber rightblk;
-	List	   *l;
+	ListCell   *l;
 
 	/* Get downlink TID from page */
 	buffer = XLogReadBuffer(false, reln, insertblk);
@@ -964,7 +964,7 @@ btree_xlog_startup(void)
 void
 btree_xlog_cleanup(void)
 {
-	List	   *l;
+	ListCell   *l;
 
 	foreach(l, incomplete_splits)
 	{

src/backend/bootstrap/bootparse.y

@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/bootstrap/bootparse.y,v 1.67 2004/05/21 05:07:56 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/bootstrap/bootparse.y,v 1.68 2004/05/26 04:41:05 neilc Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -271,7 +271,7 @@ Boot_BuildIndsStmt:
 
 boot_index_params:
 		boot_index_params COMMA boot_index_param	{ $$ = lappend($1, $3); }
-		| boot_index_param							{ $$ = makeList1($1); }
+		| boot_index_param							{ $$ = list_make1($1); }
 		;
 
 boot_index_param:
@@ -280,7 +280,7 @@ boot_index_param:
 					IndexElem *n = makeNode(IndexElem);
 					n->name = LexIDStr($1);
 					n->expr = NULL;
-					n->opclass = makeList1(makeString(LexIDStr($2)));
+					n->opclass = list_make1(makeString(LexIDStr($2)));
 					$$ = n;
 				}
 		;

src/backend/catalog/aclchk.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/catalog/aclchk.c,v 1.98 2004/05/11 17:36:12 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/catalog/aclchk.c,v 1.99 2004/05/26 04:41:06 neilc Exp $
  *
  * NOTES
  *	  See acl.h.
@@ -110,7 +110,7 @@ merge_acl_with_grant(Acl *old_acl, bool is_grant,
 					 AclId grantor_uid, AclId owner_uid)
 {
 	unsigned	modechg;
-	List	   *j;
+	ListCell   *j;
 	Acl		   *new_acl;
 
 	modechg = is_grant ? ACL_MODECHG_ADD : ACL_MODECHG_DEL;
@@ -221,16 +221,16 @@ static void
 ExecuteGrantStmt_Relation(GrantStmt *stmt)
 {
 	AclMode		privileges;
-	List	   *i;
+	ListCell   *i;
 
-	if (lfirsti(stmt->privileges) == ACL_ALL_RIGHTS)
+	if (linitial_int(stmt->privileges) == ACL_ALL_RIGHTS)
 		privileges = ACL_ALL_RIGHTS_RELATION;
 	else
 	{
 		privileges = ACL_NO_RIGHTS;
 		foreach(i, stmt->privileges)
 		{
-			AclMode		priv = lfirsti(i);
+			AclMode		priv = lfirst_int(i);
 
 			if (priv & ~((AclMode) ACL_ALL_RIGHTS_RELATION))
 				ereport(ERROR,
@@ -328,16 +328,16 @@ static void
 ExecuteGrantStmt_Database(GrantStmt *stmt)
 {
 	AclMode		privileges;
-	List	   *i;
+	ListCell   *i;
 
-	if (lfirsti(stmt->privileges) == ACL_ALL_RIGHTS)
+	if (linitial_int(stmt->privileges) == ACL_ALL_RIGHTS)
 		privileges = ACL_ALL_RIGHTS_DATABASE;
 	else
 	{
 		privileges = ACL_NO_RIGHTS;
 		foreach(i, stmt->privileges)
 		{
-			AclMode		priv = lfirsti(i);
+			AclMode		priv = lfirst_int(i);
 
 			if (priv & ~((AclMode) ACL_ALL_RIGHTS_DATABASE))
 				ereport(ERROR,
@@ -433,16 +433,16 @@ static void
 ExecuteGrantStmt_Function(GrantStmt *stmt)
 {
 	AclMode		privileges;
-	List	   *i;
+	ListCell   *i;
 
-	if (lfirsti(stmt->privileges) == ACL_ALL_RIGHTS)
+	if (linitial_int(stmt->privileges) == ACL_ALL_RIGHTS)
 		privileges = ACL_ALL_RIGHTS_FUNCTION;
 	else
 	{
 		privileges = ACL_NO_RIGHTS;
 		foreach(i, stmt->privileges)
 		{
-			AclMode		priv = lfirsti(i);
+			AclMode		priv = lfirst_int(i);
 
 			if (priv & ~((AclMode) ACL_ALL_RIGHTS_FUNCTION))
 				ereport(ERROR,
@@ -534,16 +534,16 @@ static void
 ExecuteGrantStmt_Language(GrantStmt *stmt)
 {
 	AclMode		privileges;
-	List	   *i;
+	ListCell   *i;
 
-	if (lfirsti(stmt->privileges) == ACL_ALL_RIGHTS)
+	if (linitial_int(stmt->privileges) == ACL_ALL_RIGHTS)
 		privileges = ACL_ALL_RIGHTS_LANGUAGE;
 	else
 	{
 		privileges = ACL_NO_RIGHTS;
 		foreach(i, stmt->privileges)
 		{
-			AclMode		priv = lfirsti(i);
+			AclMode		priv = lfirst_int(i);
 
 			if (priv & ~((AclMode) ACL_ALL_RIGHTS_LANGUAGE))
 				ereport(ERROR,
@@ -643,16 +643,16 @@ static void
 ExecuteGrantStmt_Namespace(GrantStmt *stmt)
 {
 	AclMode		privileges;
-	List	   *i;
+	ListCell   *i;
 
-	if (lfirsti(stmt->privileges) == ACL_ALL_RIGHTS)
+	if (linitial_int(stmt->privileges) == ACL_ALL_RIGHTS)
 		privileges = ACL_ALL_RIGHTS_NAMESPACE;
 	else
 	{
 		privileges = ACL_NO_RIGHTS;
 		foreach(i, stmt->privileges)
 		{
-			AclMode		priv = lfirsti(i);
+			AclMode		priv = lfirst_int(i);
 
 			if (priv & ~((AclMode) ACL_ALL_RIGHTS_NAMESPACE))
 				ereport(ERROR,

src/backend/catalog/dependency.c

@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/catalog/dependency.c,v 1.35 2004/05/05 04:48:45 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/catalog/dependency.c,v 1.36 2004/05/26 04:41:06 neilc Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -841,7 +841,7 @@ recordDependencyOnExpr(const ObjectAddress *depender,
 	init_object_addresses(&context.addrs);
 
 	/* Set up interpretation for Vars at varlevelsup = 0 */
-	context.rtables = makeList1(rtable);
+	context.rtables = list_make1(rtable);
 
 	/* Scan the expression tree for referenceable objects */
 	find_expr_references_walker(expr, &context);
@@ -883,7 +883,7 @@ recordDependencyOnSingleRelExpr(const ObjectAddress *depender,
 	rte.rtekind = RTE_RELATION;
 	rte.relid = relId;
 
-	context.rtables = makeList1(makeList1(&rte));
+	context.rtables = list_make1(list_make1(&rte));
 
 	/* Scan the expression tree for referenceable objects */
 	find_expr_references_walker(expr, &context);
@@ -960,24 +960,14 @@ find_expr_references_walker(Node *node,
 	if (IsA(node, Var))
 	{
 		Var		   *var = (Var *) node;
-		int			levelsup;
-		List	   *rtable,
-				   *rtables;
+		List	   *rtable;
 		RangeTblEntry *rte;
 
 		/* Find matching rtable entry, or complain if not found */
-		levelsup = var->varlevelsup;
-		rtables = context->rtables;
-		while (levelsup--)
-		{
-			if (rtables == NIL)
-				break;
-			rtables = lnext(rtables);
-		}
-		if (rtables == NIL)
+		if (var->varlevelsup >= list_length(context->rtables))
 			elog(ERROR, "invalid varlevelsup %d", var->varlevelsup);
-		rtable = lfirst(rtables);
-		if (var->varno <= 0 || var->varno > length(rtable))
+		rtable = (List *) list_nth(context->rtables, var->varlevelsup);
+		if (var->varno <= 0 || var->varno > list_length(rtable))
 			elog(ERROR, "invalid varno %d", var->varno);
 		rte = rt_fetch(var->varno, rtable);
 		if (rte->rtekind == RTE_RELATION)
@@ -994,13 +984,15 @@ find_expr_references_walker(Node *node,
 
 			/* We must make the context appropriate for join's level */
 			save_rtables = context->rtables;
-			context->rtables = rtables;
+			context->rtables = list_copy_tail(context->rtables,
+											  var->varlevelsup);
 			if (var->varattno <= 0 ||
-				var->varattno > length(rte->joinaliasvars))
+				var->varattno > list_length(rte->joinaliasvars))
 				elog(ERROR, "invalid varattno %d", var->varattno);
-			find_expr_references_walker((Node *) nth(var->varattno - 1,
-													 rte->joinaliasvars),
+			find_expr_references_walker((Node *) list_nth(rte->joinaliasvars,
+														  var->varattno - 1),
 										context);
+			list_free(context->rtables);
 			context->rtables = save_rtables;
 		}
 		return false;
@@ -1056,11 +1048,11 @@ find_expr_references_walker(Node *node,
 	if (IsA(node, SubLink))
 	{
 		SubLink    *sublink = (SubLink *) node;
-		List	   *opid;
+		ListCell   *opid;
 
 		foreach(opid, sublink->operOids)
 		{
-			add_object_address(OCLASS_OPERATOR, lfirsto(opid), 0,
+			add_object_address(OCLASS_OPERATOR, lfirst_oid(opid), 0,
 							   &context->addrs);
 		}
 		/* fall through to examine arguments */
@@ -1074,7 +1066,7 @@ find_expr_references_walker(Node *node,
 	{
 		/* Recurse into RTE subquery or not-yet-planned sublink subquery */
 		Query	   *query = (Query *) node;
-		List	   *rtable;
+		ListCell   *rtable;
 		bool		result;
 
 		/*
@@ -1099,7 +1091,7 @@ find_expr_references_walker(Node *node,
 								   find_expr_references_walker,
 								   (void *) context,
 								   QTW_IGNORE_JOINALIASES);
-		context->rtables = lnext(context->rtables);
+		context->rtables = list_delete_first(context->rtables);
 		return result;
 	}
 	return expression_tree_walker(node, find_expr_references_walker,