Fix xmlconcat by properly merging the XML declarations. Add aggregate

function xmlagg.

src/backend/executor/execQual.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/executor/execQual.c,v 1.207 2007/01/14 13:11:53 petere Exp $
+ *	  $PostgreSQL: pgsql/src/backend/executor/execQual.c,v 1.208 2007/01/20 09:27:19 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -2651,7 +2651,6 @@ ExecEvalXml(XmlExprState *xmlExpr, ExprContext *econtext,
 	StringInfoData 	buf;
 	Datum			value;
 	bool 			isnull;
-	char		   *str;
 	ListCell 	   *arg;
 	ListCell   *narg;
 	int 			i;
@@ -2663,20 +2662,22 @@ ExecEvalXml(XmlExprState *xmlExpr, ExprContext *econtext,
 	switch (xexpr->op)
 	{
 		case IS_XMLCONCAT:
-			initStringInfo(&buf);
-			foreach(arg, xmlExpr->args)
 			{
-				ExprState 	*e = (ExprState *) lfirst(arg);
+				List *values = NIL;
 
-				value = ExecEvalExpr(e, econtext, &isnull, NULL);
-				if (!isnull)
+				foreach(arg, xmlExpr->args)
+				{
+					ExprState 	*e = (ExprState *) lfirst(arg);
+
+					value = ExecEvalExpr(e, econtext, &isnull, NULL);
+					if (!isnull)
+						values = lappend(values, DatumGetPointer(value));
+				}
+
+				if (list_length(values) > 0)
 				{
-					/* we know the value is XML type */
-					str = DatumGetCString(DirectFunctionCall1(xml_out,
-															  value));
-					appendStringInfoString(&buf, str);
-					pfree(str);
 					*isNull = false;
+					return PointerGetDatum(xmlconcat(values));
 				}
 			}
 			break;

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 1.19 2007/01/19 16:58:46 petere Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/adt/xml.c,v 1.20 2007/01/20 09:27:19 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -359,6 +359,102 @@ xmlcomment(PG_FUNCTION_ARGS)
 }
 
 
+
+/*
+ * TODO: xmlconcat needs to merge the notations and unparsed entities
+ * of the argument values.  Not very important in practice, though.
+ */
+xmltype *
+xmlconcat(List *args)
+{
+#ifdef USE_LIBXML
+	StringInfoData buf;
+	ListCell   *v;
+
+	int			global_standalone = 1;
+	xmlChar	   *global_version = NULL;
+	bool		global_version_no_value = false;
+
+	initStringInfo(&buf);
+	foreach(v, args)
+	{
+		size_t		len;
+		xmlChar	   *version;
+		int			standalone;
+		xmltype	   *x = DatumGetXmlP(PointerGetDatum(lfirst(v)));
+		char	   *str;
+
+		len = VARSIZE(x) - VARHDRSZ;
+		str = palloc(len + 1);
+		memcpy(str, VARDATA(x), len);
+		str[len] = '\0';
+
+		parse_xml_decl((xmlChar *) str, &len, &version, NULL, &standalone);
+
+		if (standalone == 0 && global_standalone == 1)
+			global_standalone = 0;
+		if (standalone < 0)
+			global_standalone = -1;
+
+		if (!global_version)
+			global_version = xmlStrdup(version);
+		else if (version && xmlStrcmp(version, global_version) != 0)
+			global_version_no_value = true;
+
+		appendStringInfoString(&buf, str + len);
+		pfree(str);
+	}
+
+	if (!global_version_no_value || global_standalone >= 0)
+	{
+		StringInfoData buf2;
+
+		initStringInfo(&buf2);
+
+		if (!global_version_no_value && global_version)
+			appendStringInfo(&buf2, "<?xml version=\"%s\"", global_version);
+		else
+			appendStringInfo(&buf2, "<?xml version=\"%s\"", PG_XML_DEFAULT_VERSION);
+
+		if (global_standalone == 1)
+			appendStringInfoString(&buf2, " standalone=\"yes\"");
+		else if (global_standalone == 0)
+			appendStringInfoString(&buf2, " standalone=\"no\"");
+
+		appendStringInfoString(&buf2, "?>");
+
+		appendStringInfoString(&buf2, buf.data);
+		buf = buf2;
+	}
+
+	return stringinfo_to_xmltype(&buf);
+#else
+	NO_XML_SUPPORT();
+	return NULL;
+#endif
+}
+
+
+/*
+ * XMLAGG support
+ */
+Datum
+xmlconcat2(PG_FUNCTION_ARGS)
+{
+	if (PG_ARGISNULL(0))
+	{
+		if (PG_ARGISNULL(1))
+			PG_RETURN_NULL();
+		else
+			PG_RETURN_XML_P(PG_GETARG_XML_P(1));
+	}
+	else if (PG_ARGISNULL(1))
+		PG_RETURN_XML_P(PG_GETARG_XML_P(0));
+	else
+		PG_RETURN_XML_P(xmlconcat(list_make2(PG_GETARG_XML_P(0), PG_GETARG_XML_P(1))));
+}
+
+
 Datum
 texttoxml(PG_FUNCTION_ARGS)
 {

src/include/catalog/catversion.h

@@ -37,7 +37,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.372 2007/01/16 21:41:13 neilc Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.373 2007/01/20 09:27:19 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	200701161
+#define CATALOG_VERSION_NO	200701201
 
 #endif

src/include/catalog/pg_aggregate.h

@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/pg_aggregate.h,v 1.59 2007/01/05 22:19:52 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/pg_aggregate.h,v 1.60 2007/01/20 09:27:19 petere Exp $
  *
  * NOTES
  *	  the genbki.sh script reads this file and generates .bki
@@ -221,6 +221,9 @@ DATA(insert ( 2241 int8or		  -					0	20		_null_ ));
 DATA(insert ( 2242 bitand		  -					0	1560	_null_ ));
 DATA(insert ( 2243 bitor		  -					0	1560	_null_ ));
 
+/* xml */
+DATA(insert ( 2901 xmlconcat2	  -					0	142		_null_ ));
+
 /*
  * prototypes for functions in pg_aggregate.c
  */

src/include/catalog/pg_proc.h

@@ -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/include/catalog/pg_proc.h,v 1.437 2007/01/16 21:41:13 neilc Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/pg_proc.h,v 1.438 2007/01/20 09:27:19 petere Exp $
  *
  * NOTES
  *	  The script catalog/genbki.sh reads this file and generates .bki
@@ -4037,6 +4037,10 @@ DATA(insert OID = 2898 (  xml_recv		   PGNSP PGUID 12 f f t f s 1 142 "2281" _nu
 DESCR("I/O");
 DATA(insert OID = 2899 (  xml_send		   PGNSP PGUID 12 f f t f s 1 17 "142" _null_ _null_ _null_	xml_send - _null_ ));
 DESCR("I/O");
+DATA(insert OID = 2900 (  xmlconcat2       PGNSP PGUID 12 f f f f i 2 142 "142 142" _null_ _null_ _null_ xmlconcat2 - _null_ ));
+DESCR("aggregate transition function");
+DATA(insert OID = 2901 (  xmlagg           PGNSP PGUID 12 t f f f i 1 142 "142" _null_ _null_ _null_ aggregate_dummy - _null_ ));
+DESCR("concatenate XML values");
 
 
 /*

src/include/utils/xml.h

@@ -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/include/utils/xml.h,v 1.11 2007/01/19 16:58:46 petere Exp $
+ * $PostgreSQL: pgsql/src/include/utils/xml.h,v 1.12 2007/01/20 09:27:20 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -30,9 +30,11 @@ extern Datum xml_out(PG_FUNCTION_ARGS);
 extern Datum xml_recv(PG_FUNCTION_ARGS);
 extern Datum xml_send(PG_FUNCTION_ARGS);
 extern Datum xmlcomment(PG_FUNCTION_ARGS);
+extern Datum xmlconcat2(PG_FUNCTION_ARGS);
 extern Datum texttoxml(PG_FUNCTION_ARGS);
 extern Datum xmlvalidate(PG_FUNCTION_ARGS);
 
+extern xmltype *xmlconcat(List *args);
 extern xmltype *xmlelement(XmlExprState *xmlExpr, ExprContext *econtext);
 extern xmltype *xmlparse(text *data, bool is_doc, bool preserve_whitespace);
 extern xmltype *xmlpi(char *target, text *arg, bool arg_is_null, bool *result_is_null);

src/test/regress/expected/xml.out

@@ -55,6 +55,12 @@ ERROR:  argument of XMLCONCAT must be type xml, not type integer
 SELECT xmlconcat('bad', '<syntax');
 ERROR:  invalid XML content
 DETAIL:  Expected '>'
+SELECT xmlconcat('<foo/>', NULL, '<?xml version="1.1" standalone="no"?><bar/>');
+                     xmlconcat                     
+---------------------------------------------------
+ <?xml version="1.1" standalone="no"?><foo/><bar/>
+(1 row)
+
 SELECT xmlelement(name element,
                   xmlattributes (1 as one, 'deuce' as two),
                   'content');
@@ -190,7 +196,7 @@ SELECT xmlpi(name foo, '   bar');
 (1 row)
 
 SELECT xmlroot(xml '<foo/>', version no value, standalone no value);
-        xmlroot        
+ xmlroot 
 ---------
  <foo/>
  
@@ -268,6 +274,24 @@ SELECT xml 'abc' IS NOT DOCUMENT;
 SELECT '<>' IS NOT DOCUMENT;
 ERROR:  invalid XML content
 DETAIL:  Element name not found
+SELECT xmlagg(data) FROM xmltest;
+                xmlagg                
+--------------------------------------
+ <value>one</value><value>two</value>
+(1 row)
+
+SELECT xmlagg(data) FROM xmltest WHERE id > 10;
+ xmlagg 
+--------
+ 
+(1 row)
+
+SELECT xmlelement(name employees, xmlagg(xmlelement(name name, name))) FROM emp;
+                                                           xmlelement                                                           
+--------------------------------------------------------------------------------------------------------------------------------
+ <employees><name>sharon</name><name>sam</name><name>bill</name><name>jeff</name><name>cim</name><name>linda</name></employees>
+(1 row)
+
 -- Check mapping SQL identifier to XML name
 SELECT xmlpi(name ":::_xml_abc135.%-&_");
                       xmlpi                      

src/test/regress/expected/xml_1.out

@@ -33,6 +33,8 @@ SELECT xmlconcat(1, 2);
 ERROR:  argument of XMLCONCAT must be type xml, not type integer
 SELECT xmlconcat('bad', '<syntax');
 ERROR:  no XML support in this installation
+SELECT xmlconcat('<foo/>', NULL, '<?xml version="1.1" standalone="no"?><bar/>');
+ERROR:  no XML support in this installation
 SELECT xmlelement(name element,
                   xmlattributes (1 as one, 'deuce' as two),
                   'content');
@@ -123,6 +125,20 @@ SELECT xml 'abc' IS NOT DOCUMENT;
 ERROR:  no XML support in this installation
 SELECT '<>' IS NOT DOCUMENT;
 ERROR:  no XML support in this installation
+SELECT xmlagg(data) FROM xmltest;
+ xmlagg 
+--------
+ 
+(1 row)
+
+SELECT xmlagg(data) FROM xmltest WHERE id > 10;
+ xmlagg 
+--------
+ 
+(1 row)
+
+SELECT xmlelement(name employees, xmlagg(xmlelement(name name, name))) FROM emp;
+ERROR:  no XML support in this installation
 -- Check mapping SQL identifier to XML name
 SELECT xmlpi(name ":::_xml_abc135.%-&_");
 ERROR:  no XML support in this installation

src/test/regress/sql/xml.sql

@@ -24,6 +24,7 @@ SELECT xmlconcat(xmlcomment('hello'),
 SELECT xmlconcat('hello', 'you');
 SELECT xmlconcat(1, 2);
 SELECT xmlconcat('bad', '<syntax');
+SELECT xmlconcat('<foo/>', NULL, '<?xml version="1.1" standalone="no"?><bar/>');
 
 
 SELECT xmlelement(name element,
@@ -97,6 +98,11 @@ SELECT xml 'abc' IS NOT DOCUMENT;
 SELECT '<>' IS NOT DOCUMENT;
 
 
+SELECT xmlagg(data) FROM xmltest;
+SELECT xmlagg(data) FROM xmltest WHERE id > 10;
+SELECT xmlelement(name employees, xmlagg(xmlelement(name name, name))) FROM emp;
+
+
 -- Check mapping SQL identifier to XML name
 
 SELECT xmlpi(name ":::_xml_abc135.%-&_");