Rip out QueryTreeList structure, root and branch. Querytree

lists are now plain old garden-variety Lists, allocated with palloc,
rather than specialized expansible-array data allocated with malloc.
This substantially simplifies their handling and eliminates several
sources of memory leakage.
Several basic types of erroneous queries (syntax error, attempt to
insert a duplicate key into a unique index) now demonstrably leak
zero bytes per query.

src/backend/parser/analyze.c

@@ -5,7 +5,7 @@
  *
  * Copyright (c) 1994, Regents of the University of California
  *
- *  $Id: analyze.c,v 1.102 1999/05/12 07:17:18 thomas Exp $
+ *  $Id: analyze.c,v 1.103 1999/05/13 07:28:34 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -59,17 +59,12 @@ List	   *extras_after = NIL;
  * all transformed to Query while the rest stays the same.
  *
  */
-QueryTreeList *
+List *
 parse_analyze(List *pl, ParseState *parentParseState)
 {
-	QueryTreeList *result;
+	List *result = NIL;
 	ParseState *pstate;
 	Query *parsetree;
-	int			i = 0;
-
-	result = malloc(sizeof(QueryTreeList));
-	result->len = length(pl);
-	result->qtrees = (Query **) malloc(result->len * sizeof(Query *));
 
 	while (pl != NIL)
 	{
@@ -78,35 +73,25 @@ parse_analyze(List *pl, ParseState *parentParseState)
 		if (pstate->p_target_relation != NULL)
 			heap_close(pstate->p_target_relation);
 
-		if (extras_before != NIL)
+		while (extras_before != NIL)
 		{
-			result->len += length(extras_before);
-			result->qtrees = (Query **) realloc(result->qtrees, result->len * sizeof(Query *));
-			while (extras_before != NIL)
-			{
-				result->qtrees[i++] = transformStmt(pstate, lfirst(extras_before));
-				if (pstate->p_target_relation != NULL)
-					heap_close(pstate->p_target_relation);
-				extras_before = lnext(extras_before);
-			}
+			result = lappend(result,
+							 transformStmt(pstate, lfirst(extras_before)));
+			if (pstate->p_target_relation != NULL)
+				heap_close(pstate->p_target_relation);
+			extras_before = lnext(extras_before);
 		}
-		extras_before = NIL;
 
-		result->qtrees[i++] = parsetree;
+		result = lappend(result, parsetree);
 
-		if (extras_after != NIL)
+		while (extras_after != NIL)
 		{
-			result->len += length(extras_after);
-			result->qtrees = (Query **) realloc(result->qtrees, result->len * sizeof(Query *));
-			while (extras_after != NIL)
-			{
-				result->qtrees[i++] = transformStmt(pstate, lfirst(extras_after));
-				if (pstate->p_target_relation != NULL)
-					heap_close(pstate->p_target_relation);
-				extras_after = lnext(extras_after);
-			}
+			result = lappend(result,
+							 transformStmt(pstate, lfirst(extras_after)));
+			if (pstate->p_target_relation != NULL)
+				heap_close(pstate->p_target_relation);
+			extras_after = lnext(extras_after);
 		}
-		extras_after = NIL;
 
 		pl = lnext(pl);
 		pfree(pstate);

src/backend/parser/parse_clause.c

@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/parser/parse_clause.c,v 1.30 1999/05/12 15:01:50 wieck Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/parser/parse_clause.c,v 1.31 1999/05/13 07:28:36 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -752,23 +752,24 @@ List *
 transformUnionClause(List *unionClause, List *targetlist)
 {
 	List	   *union_list = NIL;
-	QueryTreeList *qlist;
-	int			i;
+	List	   *qlist,
+			   *qlist_item;
 
 	if (unionClause)
 	{
 		/* recursion */
 		qlist = parse_analyze(unionClause, NULL);
 
-		for (i = 0; i < qlist->len; i++)
+		foreach (qlist_item, qlist)
 		{
+			Query	   *query = (Query *) lfirst(qlist_item);
 			List	   *prev_target = targetlist;
 			List	   *next_target;
 
-			if (length(targetlist) != length(qlist->qtrees[i]->targetList))
+			if (length(targetlist) != length(query->targetList))
 				elog(ERROR, "Each UNION clause must have the same number of columns");
 
-			foreach(next_target, qlist->qtrees[i]->targetList)
+			foreach(next_target, query->targetList)
 			{
 				Oid			itype;
 				Oid			otype;
@@ -819,7 +820,7 @@ transformUnionClause(List *unionClause, List *targetlist)
 				}
 				prev_target = lnext(prev_target);
 			}
-			union_list = lappend(union_list, qlist->qtrees[i]);
+			union_list = lappend(union_list, query);
 		}
 		return union_list;
 	}

src/backend/parser/parse_expr.c

@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/parser/parse_expr.c,v 1.44 1999/05/12 07:14:24 thomas Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/parser/parse_expr.c,v 1.45 1999/05/13 07:28:38 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -274,16 +274,19 @@ transformExpr(ParseState *pstate, Node *expr, int precedence)
 		case T_SubLink:
 			{
 				SubLink    *sublink = (SubLink *) expr;
-				QueryTreeList *qtree;
+				List	   *qtrees;
+				Query	   *qtree;
 				List	   *llist;
 
 				pstate->p_hasSubLinks = true;
-				qtree = parse_analyze(lcons(sublink->subselect, NIL), pstate);
-				if (qtree->len != 1 ||
-					qtree->qtrees[0]->commandType != CMD_SELECT ||
-					qtree->qtrees[0]->resultRelation != 0)
+				qtrees = parse_analyze(lcons(sublink->subselect, NIL), pstate);
+				if (length(qtrees) != 1)
 					elog(ERROR, "parser: bad query in subselect");
-				sublink->subselect = (Node *) qtree->qtrees[0];
+				qtree = (Query *) lfirst(qtrees);
+				if (qtree->commandType != CMD_SELECT ||
+					qtree->resultRelation != 0)
+					elog(ERROR, "parser: bad query in subselect");
+				sublink->subselect = (Node *) qtree;
 
 				if (sublink->subLinkType != EXISTS_SUBLINK)
 				{

src/backend/parser/parser.c

@@ -6,7 +6,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/parser/parser.c,v 1.37 1999/02/13 23:17:10 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/parser/parser.c,v 1.38 1999/05/13 07:28:39 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -20,34 +20,32 @@
 #include "parser/parse_node.h"
 #include "parser/parser.h"
 
+#if defined(FLEX_SCANNER)
+extern void DeleteBuffer(void);
+#endif	 /* FLEX_SCANNER */
+
 char	   *parseString;		/* the char* which holds the string to be
 								 * parsed */
-List	   *parsetree = NIL;
+List	   *parsetree;			/* result of parsing is left here */
 
 #ifdef SETS_FIXED
 static void fixupsets();
 static void define_sets();
-
 #endif
+
 /*
  * parser-- returns a list of parse trees
- *
- *	CALLER is responsible for free'ing the list returned
  */
-QueryTreeList *
+List *
 parser(char *str, Oid *typev, int nargs)
 {
-	QueryTreeList *queryList;
+	List	   *queryList;
 	int			yyresult;
 
-#if defined(FLEX_SCANNER)
-	extern void DeleteBuffer(void);
-
-#endif	 /* FLEX_SCANNER */
-
 	init_io();
 
 	parseString = pstrdup(str);
+	parsetree = NIL;			/* in case parser forgets to set it */
 
 	parser_init(typev, nargs);
 	yyresult = yyparse();
@@ -59,7 +57,7 @@ parser(char *str, Oid *typev, int nargs)
 	clearerr(stdin);
 
 	if (yyresult)				/* error */
-		return (QueryTreeList *) NULL;
+		return (List *) NULL;
 
 	queryList = parse_analyze(parsetree, NULL);