Extend EXPLAIN to support output in XML or JSON format.

There are probably still some adjustments to be made in the details
of the output, but this gets the basic structure in place.

Robert Haas

1 files changed, 40 insertions, 27 deletions

diff --git a/src/backend/utils/adt/xml.c b/src/backend/utils/adt/xml.c
index b92d41b93cc..80e113329ce 100644
--- a/src/backend/utils/adt/xml.c
+++ b/src/backend/utils/adt/xml.c
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/backend/utils/adt/xml.c,v 1.92 2009/06/11 14:49:04 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/adt/xml.c,v 1.93 2009/08/10 05:46:50 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1593,8 +1593,6 @@ map_xml_name_to_sql_identifier(char *name)
 char *
 map_sql_value_to_xml_value(Datum value, Oid type, bool xml_escape_strings)
 {
-	StringInfoData buf;
-
 	if (type_is_array(type))
 	{
 		ArrayType  *array;
@@ -1605,6 +1603,7 @@ map_sql_value_to_xml_value(Datum value, Oid type, bool xml_escape_strings)
 		int			num_elems;
 		Datum	   *elem_values;
 		bool	   *elem_nulls;
+		StringInfoData buf;
 		int			i;
 
 		array = DatumGetArrayTypeP(value);
@@ -1638,8 +1637,7 @@ map_sql_value_to_xml_value(Datum value, Oid type, bool xml_escape_strings)
 	{
 		Oid			typeOut;
 		bool		isvarlena;
-		char	   *p,
-				   *str;
+		char	   *str;
 
 		/*
 		 * Special XSD formatting for some data types
@@ -1788,32 +1786,47 @@ map_sql_value_to_xml_value(Datum value, Oid type, bool xml_escape_strings)
 			return str;
 
 		/* otherwise, translate special characters as needed */
-		initStringInfo(&buf);
+		return escape_xml(str);
+	}
+}
 
-		for (p = str; *p; p++)
+
+/*
+ * Escape characters in text that have special meanings in XML.
+ *
+ * Returns a palloc'd string.
+ *
+ * NB: this is intentionally not dependent on libxml.
+ */
+char *
+escape_xml(const char *str)
+{
+	StringInfoData buf;
+	const char *p;
+
+	initStringInfo(&buf);
+	for (p = str; *p; p++)
+	{
+		switch (*p)
 		{
-			switch (*p)
-			{
-				case '&':
-					appendStringInfoString(&buf, "&");
-					break;
-				case '<':
-					appendStringInfoString(&buf, "&lt;");
-					break;
-				case '>':
-					appendStringInfoString(&buf, "&gt;");
-					break;
-				case '\r':
-					appendStringInfoString(&buf, "&#x0d;");
-					break;
-				default:
-					appendStringInfoCharMacro(&buf, *p);
-					break;
-			}
+			case '&':
+				appendStringInfoString(&buf, "&amp;");
+				break;
+			case '<':
+				appendStringInfoString(&buf, "&lt;");
+				break;
+			case '>':
+				appendStringInfoString(&buf, "&gt;");
+				break;
+			case '\r':
+				appendStringInfoString(&buf, "&#x0d;");
+				break;
+			default:
+				appendStringInfoCharMacro(&buf, *p);
+				break;
 		}
-
-		return buf.data;
 	}
+	return buf.data;
 }