Modify readfuncs so that recursive use of stringToNode will not crash

and burn.  Just for added luck, change reading of CONST nodes so that
we do not need to consult pg_type rows while reading them; this means
that no database access occurs during stringToNode.  This requires
changing the order in which const-node fields are written, which means
an initdb is forced.

src/backend/nodes/outfuncs.c

 /*
- *
  * outfuncs.c
  *	  routines to convert a node to ascii representation
  *
  * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- *	$Header: /cvsroot/pgsql/src/backend/nodes/outfuncs.c,v 1.135 2000/12/03 20:45:33 tgl Exp $
+ *	$Header: /cvsroot/pgsql/src/backend/nodes/outfuncs.c,v 1.136 2001/01/07 01:08:47 tgl Exp $
  *
  * NOTES
  *	  Every (plan) node in POSTGRES has an associated "out" routine which
  *	  knows how to create its ascii representation. These functions are
  *	  useful for debugging as well as for storing plans in the system
- *	  catalogs (eg. indexes). This is also the plan string sent out in
- *	  Mariposa.
- *
- *	  These functions update the in/out argument of type StringInfo
- *	  passed to them. This argument contains the string holding the ASCII
- *	  representation plus some other information (string length, etc.)
- *
+ *	  catalogs (eg. views).
  */
 #include "postgres.h"
 
 #include <ctype.h>
 
-#include "access/heapam.h"
-#include "access/htup.h"
-#include "catalog/pg_type.h"
-#include "fmgr.h"
 #include "lib/stringinfo.h"
-#include "nodes/execnodes.h"
 #include "nodes/nodes.h"
 #include "nodes/parsenodes.h"
-#include "nodes/pg_list.h"
 #include "nodes/plannodes.h"
 #include "nodes/primnodes.h"
 #include "nodes/relation.h"
 #include "parser/parse.h"
 #include "utils/datum.h"
-#include "utils/lsyscache.h"
-#include "utils/syscache.h"
 
 
-static void _outDatum(StringInfo str, Datum value, Oid type);
+static void _outDatum(StringInfo str, Datum value, int typlen, bool typbyval);
 static void _outNode(StringInfo str, void *obj);
 
 /*
@@ -63,8 +48,8 @@ _outToken(StringInfo str, char *s)
 
 	/*
 	 * Look for characters or patterns that are treated specially by
-	 * read.c (either in lsptok() or in nodeRead()), and therefore need a
-	 * protective backslash.
+	 * read.c (either in pg_strtok() or in nodeRead()), and therefore need
+	 * a protective backslash.
 	 */
 	/* These characters only need to be quoted at the start of the string */
 	if (*s == '<' ||
@@ -762,18 +747,17 @@ static void
 _outConst(StringInfo str, Const *node)
 {
 	appendStringInfo(str,
-		" CONST :consttype %u :constlen %d :constisnull %s :constvalue ",
+					 " CONST :consttype %u :constlen %d :constbyval %s"
+					 " :constisnull %s :constvalue ",
 					 node->consttype,
 					 node->constlen,
+					 node->constbyval ? "true" : "false",
 					 node->constisnull ? "true" : "false");
 
 	if (node->constisnull)
 		appendStringInfo(str, "<>");
 	else
-		_outDatum(str, node->constvalue, node->consttype);
-
-	appendStringInfo(str, " :constbyval %s ",
-					 node->constbyval ? "true" : "false");
+		_outDatum(str, node->constvalue, node->constlen, node->constbyval);
 }
 
 /*
@@ -1234,38 +1218,31 @@ _outJoinInfo(StringInfo str, JoinInfo *node)
  * Print the value of a Datum given its type.
  */
 static void
-_outDatum(StringInfo str, Datum value, Oid type)
+_outDatum(StringInfo str, Datum value, int typlen, bool typbyval)
 {
-	int16		typeLength;
-	bool		byValue;
-	Size		length;
+	Size		length,
+				i;
 	char	   *s;
-	int			i;
 
-	/*
-	 * find some information about the type and the "real" length of the
-	 * datum.
-	 */
-	get_typlenbyval(type, &typeLength, &byValue);
-	length = datumGetSize(value, byValue, typeLength);
+	length = datumGetSize(value, typbyval, typlen);
 
-	if (byValue)
+	if (typbyval)
 	{
 		s = (char *) (&value);
 		appendStringInfo(str, " %u [ ", (unsigned int) length);
-		for (i = 0; i < (int) sizeof(Datum); i++)
+		for (i = 0; i < (Size) sizeof(Datum); i++)
 			appendStringInfo(str, "%d ", (int) (s[i]));
 		appendStringInfo(str, "] ");
 	}
 	else
-	{							/* !byValue */
+	{
 		s = (char *) DatumGetPointer(value);
 		if (!PointerIsValid(s))
 			appendStringInfo(str, " 0 [ ] ");
 		else
 		{
 			appendStringInfo(str, " %u [ ", (unsigned int) length);
-			for (i = 0; i < (int) length; i++)
+			for (i = 0; i < length; i++)
 				appendStringInfo(str, "%d ", (int) (s[i]));
 			appendStringInfo(str, "] ");
 		}

src/backend/nodes/read.c

@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/nodes/read.c,v 1.26 2000/12/03 20:45:33 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/nodes/read.c,v 1.27 2001/01/07 01:08:47 tgl Exp $
  *
  * HISTORY
  *	  AUTHOR			DATE			MAJOR EVENT
@@ -25,6 +25,11 @@
 #include "nodes/pg_list.h"
 #include "nodes/readfuncs.h"
 
+
+/* Static state for pg_strtok */
+static char *pg_strtok_ptr = NULL;
+
+
 /*
  * stringToNode -
  *	  returns a Node with a given legal ASCII representation
@@ -32,10 +37,22 @@
 void *
 stringToNode(char *str)
 {
+	char	   *save_strtok;
 	void	   *retval;
 
-	lsptok(str, NULL);			/* set the string used in lsptok */
-	retval = nodeRead(true);	/* start reading */
+	/*
+	 * We save and restore the pre-existing state of pg_strtok.
+	 * This makes the world safe for re-entrant invocation of stringToNode,
+	 * without incurring a lot of notational overhead by having to pass the
+	 * next-character pointer around through all the readfuncs.c code.
+	 */
+	save_strtok = pg_strtok_ptr;
+
+	pg_strtok_ptr = str;		/* point pg_strtok at the string to read */
+
+	retval = nodeRead(true);	/* do the reading */
+
+	pg_strtok_ptr = save_strtok;
 
 	return retval;
 }
@@ -47,7 +64,7 @@ stringToNode(char *str)
  *****************************************************************************/
 
 /*
- * lsptok --- retrieve next "token" from a string.
+ * pg_strtok --- retrieve next "token" from a string.
  *
  * Works kinda like strtok, except it never modifies the source string.
  * (Instead of storing nulls into the string, the length of the token
@@ -55,9 +72,7 @@ stringToNode(char *str)
  * Also, the rules about what is a token are hard-wired rather than being
  * configured by passing a set of terminating characters.
  *
- * The string is initially set by passing a non-NULL "string" value,
- * and subsequent calls with string==NULL read the previously given value.
- * (Pass length==NULL to set the string without reading its first token.)
+ * The string is assumed to have been initialized already by stringToNode.
  *
  * The rules for tokens are:
  *	* Whitespace (space, tab, newline) always separates tokens.
@@ -89,20 +104,12 @@ stringToNode(char *str)
  * as a single token.
  */
 char *
-lsptok(char *string, int *length)
+pg_strtok(int *length)
 {
-	static char *saved_str = NULL;
 	char	   *local_str;		/* working pointer to string */
 	char	   *ret_str;		/* start of token to return */
 
-	if (string != NULL)
-	{
-		saved_str = string;
-		if (length == NULL)
-			return NULL;
-	}
-
-	local_str = saved_str;
+	local_str = pg_strtok_ptr;
 
 	while (*local_str == ' ' || *local_str == '\n' || *local_str == '\t')
 		local_str++;
@@ -110,7 +117,7 @@ lsptok(char *string, int *length)
 	if (*local_str == '\0')
 	{
 		*length = 0;
-		saved_str = local_str;
+		pg_strtok_ptr = local_str;
 		return NULL;			/* no more tokens */
 	}
 
@@ -147,7 +154,7 @@ lsptok(char *string, int *length)
 	if (*length == 2 && ret_str[0] == '<' && ret_str[1] == '>')
 		*length = 0;
 
-	saved_str = local_str;
+	pg_strtok_ptr = local_str;
 
 	return ret_str;
 }
@@ -223,7 +230,7 @@ nodeTokenType(char *token, int length)
 	}
 
 	/*
-	 * these three cases do not need length checks, since lsptok() will
+	 * these three cases do not need length checks, since pg_strtok() will
 	 * always treat them as single-byte tokens
 	 */
 	else if (*token == '(')
@@ -248,12 +255,13 @@ nodeTokenType(char *token, int length)
  *	  Slightly higher-level reader.
  *
  * This routine applies some semantic knowledge on top of the purely
- * lexical tokenizer lsptok().	It can read
+ * lexical tokenizer pg_strtok().	It can read
  *	* Value token nodes (integers, floats, or strings);
  *	* Plan nodes (via parsePlanString() from readfuncs.c);
  *	* Lists of the above.
  *
- * Secrets:  He assumes that lsptok already has the string (see above).
+ * We assume pg_strtok is already initialized with a string to read (hence
+ * this should only be invoked from within a stringToNode operation).
  * Any callers should set read_car_only to true.
  */
 void *
@@ -266,7 +274,7 @@ nodeRead(bool read_car_only)
 			   *return_value;
 	bool		make_dotted_pair_cell = false;
 
-	token = lsptok(NULL, &tok_len);
+	token = pg_strtok(&tok_len);
 
 	if (token == NULL)
 		return NULL;
@@ -277,8 +285,8 @@ nodeRead(bool read_car_only)
 	{
 		case PLAN_SYM:
 			this_value = parsePlanString();
-			token = lsptok(NULL, &tok_len);
-			if (token[0] != '}')
+			token = pg_strtok(&tok_len);
+			if (token == NULL || token[0] != '}')
 				elog(ERROR, "nodeRead: did not find '}' at end of plan node");
 			if (!read_car_only)
 				make_dotted_pair_cell = true;

src/include/catalog/catversion.h

@@ -37,7 +37,7 @@
  * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: catversion.h,v 1.67 2000/12/28 13:00:27 vadim Exp $
+ * $Id: catversion.h,v 1.68 2001/01/07 01:08:48 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -53,6 +53,6 @@
  */
 
 /*                        	yyyymmddN */
-#define CATALOG_VERSION_NO	200012280
+#define CATALOG_VERSION_NO	200101061
 
 #endif

src/include/nodes/readfuncs.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: readfuncs.h,v 1.9 2000/01/26 05:58:17 momjian Exp $
+ * $Id: readfuncs.h,v 1.10 2001/01/07 01:08:48 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -19,7 +19,7 @@
 /*
  * prototypes for functions in read.c (the lisp token parser)
  */
-extern char *lsptok(char *string, int *length);
+extern char *pg_strtok(int *length);
 extern char *debackslash(char *token, int length);
 extern void *nodeRead(bool read_car_only);