Implement XMLSERIALIZE for real. Analogously, make the xml to text cast

observe the xmloption.

Reorganize the representation of the XML option in the parse tree and the
API to make it easier to manage and understand.

Add regression tests for parsing back XML expressions.

1 files changed, 32 insertions, 10 deletions

diff --git a/src/backend/utils/adt/xml.c b/src/backend/utils/adt/xml.c
index 7d963148d0e..70e566327da 100644
--- a/src/backend/utils/adt/xml.c
+++ b/src/backend/utils/adt/xml.c
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/backend/utils/adt/xml.c,v 1.24 2007/01/27 14:50:51 petere Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/adt/xml.c,v 1.25 2007/02/03 14:06:55 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -80,7 +80,7 @@ static void 	xml_ereport_by_code(int level, int sqlcode,
 static xmlChar *xml_text2xmlChar(text *in);
 static int		parse_xml_decl(const xmlChar *str, size_t *lenp, xmlChar **version, xmlChar **encoding, int *standalone);
 static bool		print_xml_decl(StringInfo buf, const xmlChar *version, pg_enc encoding, int standalone);
-static xmlDocPtr xml_parse(text *data, bool is_document, bool preserve_whitespace, xmlChar *encoding);
+static xmlDocPtr xml_parse(text *data, XmlOptionType xmloption_arg, bool preserve_whitespace, xmlChar *encoding);
 
 #endif /* USE_LIBXML */
 
@@ -112,7 +112,7 @@ xml_in(PG_FUNCTION_ARGS)
 	 * Parse the data to check if it is well-formed XML data.  Assume
 	 * that ERROR occurred if parsing failed.
 	 */
-	doc = xml_parse(vardata, (xmloption == XMLOPTION_DOCUMENT), true, NULL);
+	doc = xml_parse(vardata, xmloption, true, NULL);
 	xmlFreeDoc(doc);
 
 	PG_RETURN_XML_P(vardata);
@@ -211,7 +211,7 @@ xml_recv(PG_FUNCTION_ARGS)
 	 * Parse the data to check if it is well-formed XML data.  Assume
 	 * that ERROR occurred if parsing failed.
 	 */
-	doc = xml_parse(result, (xmloption == XMLOPTION_DOCUMENT), true, encoding);
+	doc = xml_parse(result, xmloption, true, encoding);
 	xmlFreeDoc(doc);
 
 	newstr = (char *) pg_do_encoding_conversion((unsigned char *) str,
@@ -435,7 +435,29 @@ texttoxml(PG_FUNCTION_ARGS)
 {
 	text	   *data = PG_GETARG_TEXT_P(0);
 
-	PG_RETURN_XML_P(xmlparse(data, (xmloption == XMLOPTION_DOCUMENT), true));
+	PG_RETURN_XML_P(xmlparse(data, xmloption, true));
+}
+
+
+Datum
+xmltotext(PG_FUNCTION_ARGS)
+{
+	xmltype	   *data = PG_GETARG_XML_P(0);
+
+	PG_RETURN_TEXT_P(xmltotext_with_xmloption(data, xmloption));
+}
+
+
+text *
+xmltotext_with_xmloption(xmltype *data, XmlOptionType xmloption_arg)
+{
+	if (xmloption_arg == XMLOPTION_DOCUMENT && !xml_is_document(data))
+		ereport(ERROR,
+				(errcode(ERRCODE_NOT_AN_XML_DOCUMENT),
+				 errmsg("not an XML document")));
+
+	/* It's actually binary compatible, save for the above check. */
+	return (text *) data;
 }
 
 
@@ -499,12 +521,12 @@ xmlelement(XmlExprState *xmlExpr, ExprContext *econtext)
 
 
 xmltype *
-xmlparse(text *data, bool is_document, bool preserve_whitespace)
+xmlparse(text *data, XmlOptionType xmloption_arg, bool preserve_whitespace)
 {
 #ifdef USE_LIBXML
 	xmlDocPtr	doc;
 
-	doc = xml_parse(data, is_document, preserve_whitespace, NULL);
+	doc = xml_parse(data, xmloption_arg, preserve_whitespace, NULL);
 	xmlFreeDoc(doc);
 
 	return (xmltype *) data;
@@ -723,7 +745,7 @@ xml_is_document(xmltype *arg)
 
 	PG_TRY();
 	{
-		doc = xml_parse((text *) arg, true, true, NULL);
+		doc = xml_parse((text *) arg, XMLOPTION_DOCUMENT, true, NULL);
 		result = true;
 	}
 	PG_CATCH();
@@ -996,7 +1018,7 @@ print_xml_decl(StringInfo buf, const xmlChar *version, pg_enc encoding, int stan
  * TODO maybe, libxml2's xmlreader is better? (do not construct DOM, yet do not use SAX - see xml_reader.c)
  */
 static xmlDocPtr
-xml_parse(text *data, bool is_document, bool preserve_whitespace, xmlChar *encoding)
+xml_parse(text *data, XmlOptionType xmloption_arg, bool preserve_whitespace, xmlChar *encoding)
 {
 	int32				len;
 	xmlChar				*string;
@@ -1024,7 +1046,7 @@ xml_parse(text *data, bool is_document, bool preserve_whitespace, xmlChar *encod
 			xml_ereport(ERROR, ERRCODE_INTERNAL_ERROR,
 						"could not allocate parser context");
 
-		if (is_document)
+		if (xmloption_arg == XMLOPTION_DOCUMENT)
 		{
 			/*
 			 * Note, that here we try to apply DTD defaults