[CF 5279] v6 - Add XMLSerialize: version (SQL/XML X076), explicit declaration (SQL/XML X078)

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Patch(es): https://www.postgresql.org/message-id/[email protected]
Author(s): Jim Jones

Author: Commitfest Bot

doc/src/sgml/datatype.sgml

@@ -4518,7 +4518,10 @@ xml '<foo>bar</foo>'
     <type>xml</type>, uses the function
     <function>xmlserialize</function>:<indexterm><primary>xmlserialize</primary></indexterm>
 <synopsis>
-XMLSERIALIZE ( { DOCUMENT | CONTENT } <replaceable>value</replaceable> AS <replaceable>type</replaceable> [ [ NO ] INDENT ] )
+XMLSERIALIZE ( { DOCUMENT | CONTENT } <replaceable>value</replaceable> AS <replaceable>type</replaceable>
+     [ VERSION <replaceable>xmlversion</replaceable> ]
+     [ INCLUDING XMLDECLARATION | EXCLUDING XMLDECLARATION ]
+     [ [ NO ] INDENT ] )
 </synopsis>
     <replaceable>type</replaceable> can be
     <type>character</type>, <type>character varying</type>, or
@@ -4528,13 +4531,77 @@ XMLSERIALIZE ( { DOCUMENT | CONTENT } <replaceable>value</replaceable> AS <repla
     you to simply cast the value.
    </para>
 
+   <para>
+     The <literal>VERSION</literal> option sets the version string
+     used in the XML declaration. If specified, the value of
+     <replaceable>xmlversion</replaceable> must conform to the lexical
+     rules of the XML standard: it must be a string of the form
+     <literal>'1.'</literal> followed by one or more digits (e.g.,
+     <literal>'1.0'</literal>, <literal>'1.1'</literal>). Versions other
+     than 1.x (e.g., <literal>'2.0'</literal>) are not valid in
+     <literal>DOCUMENT</literal> mode and will result in an error. This format
+     is defined in section 2.8,
+     <ulink url="https://www.w3.org/TR/xml/#sec-prolog-dtd">"Prolog and Document Type Declaration"</ulink>,
+     of the XML standard. If the <literal>VERSION</literal> option is omitted or specified as
+     <literal>NULL</literal>, version <literal>1.0</literal> is used by default.
+
+     In <literal>CONTENT</literal> mode, no validation is performed on the version,
+     and it is emitted as specified if an XML declaration is requested.
+   </para>
+
+    <para>
+     The <literal>INCLUDING XMLDECLARATION</literal> and
+     <literal>EXCLUDING XMLDECLARATION</literal> options control
+     whether the serialized output includes an XML declaration such as
+     <literal>&lt;?xml version="1.0" encoding="UTF-8"?&gt;</literal>.
+     If neither option is specified, the presence of the declaration in
+     the output depends on whether the input <replaceable>value</replaceable>
+     originally contained one.
+
+     The <literal>INCLUDING XMLDECLARATION</literal> option is allowed in both
+     <literal>DOCUMENT</literal> and <literal>CONTENT</literal> modes. In
+     <literal>CONTENT</literal> mode, no structural validation is performed,
+     and the declaration is emitted according to the specified options,
+     even if it would not normally be considered valid by the XML specification.
+   </para>
+
    <para>
     The <literal>INDENT</literal> option causes the result to be
     pretty-printed, while <literal>NO INDENT</literal> (which is the
     default) just emits the original input string.  Casting to a character
     type likewise produces the original string.
    </para>
 
+   <para>
+Examples:
+   </para>
+<screen><![CDATA[
+SELECT
+  xmlserialize(
+    DOCUMENT xmlelement(name foo, xmlelement(name bar,42)) AS text
+    VERSION '1.0'
+    INCLUDING XMLDECLARATION
+    INDENT);
+
+             xmlserialize
+---------------------------------------
+ <?xml version="1.0" encoding="UTF8"?>+
+ <foo>                                +
+   <bar>42</bar>                      +
+ </foo>
+(1 row)
+
+SELECT
+  xmlserialize(
+    DOCUMENT '<?xml version="1.0" encoding="UTF-8"?><foo><bar>42</bar></foo>' AS text
+    EXCLUDING XMLDECLARATION);
+
+       xmlserialize
+--------------------------
+ <foo><bar>42</bar></foo>
+(1 row)
+]]></screen>
+
    <para>
     When a character string value is cast to or from type
     <type>xml</type> without going through <type>XMLPARSE</type> or

src/backend/catalog/sql_features.txt

@@ -665,9 +665,9 @@ X072	XMLSerialize: character string serialization			YES
 X073	XMLSerialize: binary string serialization and CONTENT option			NO	
 X074	XMLSerialize: binary string serialization and DOCUMENT option			NO	
 X075	XMLSerialize: binary string serialization			NO	
-X076	XMLSerialize: VERSION			NO	
+X076	XMLSerialize: VERSION			YES	
 X077	XMLSerialize: explicit ENCODING option			NO	
-X078	XMLSerialize: explicit XML declaration			NO	
+X078	XMLSerialize: explicit XML declaration			YES	
 X080	Namespaces in XML publishing			NO	
 X081	Query-level XML namespace declarations			NO	
 X082	XML namespace declarations in DML			NO	

src/backend/executor/execExprInterp.c

@@ -4621,7 +4621,9 @@ ExecEvalXmlExpr(ExprState *state, ExprEvalStep *op)
 				*op->resvalue =
 					PointerGetDatum(xmltotext_with_options(DatumGetXmlP(value),
 														   xexpr->xmloption,
-														   xexpr->indent));
+														   xexpr->indent,
+														   xexpr->xmldeclaration,
+														   xexpr->version));
 				*op->resnull = false;
 			}
 			break;

src/backend/parser/gram.y

@@ -626,6 +626,8 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 %type <defelt>	xmltable_column_option_el
 %type <list>	xml_namespace_list
 %type <target>	xml_namespace_el
+%type <ival> 	opt_xml_declaration_option
+%type <str>		opt_xml_declaration_version xmlserialize_version
 
 %type <node>	func_application func_expr_common_subexpr
 %type <node>	func_expr func_expr_windowless
@@ -794,8 +796,8 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 
 	WHEN WHERE WHITESPACE_P WINDOW WITH WITHIN WITHOUT WORK WRAPPER WRITE
 
-	XML_P XMLATTRIBUTES XMLCONCAT XMLELEMENT XMLEXISTS XMLFOREST XMLNAMESPACES
-	XMLPARSE XMLPI XMLROOT XMLSERIALIZE XMLTABLE
+	XML_P XMLATTRIBUTES XMLCONCAT XMLDECLARATION XMLELEMENT XMLEXISTS XMLFOREST
+	XMLNAMESPACES XMLPARSE XMLPI XMLROOT XMLSERIALIZE XMLTABLE
 
 	YEAR_P YES_P
 
@@ -16200,14 +16202,16 @@ func_expr_common_subexpr:
 					$$ = makeXmlExpr(IS_XMLROOT, NULL, NIL,
 									 list_make3($3, $5, $6), @1);
 				}
-			| XMLSERIALIZE '(' document_or_content a_expr AS SimpleTypename xml_indent_option ')'
+			| XMLSERIALIZE '(' document_or_content a_expr AS SimpleTypename opt_xml_declaration_version opt_xml_declaration_option xml_indent_option ')'
 				{
 					XmlSerialize *n = makeNode(XmlSerialize);
 
 					n->xmloption = $3;
 					n->expr = $4;
 					n->typeName = $6;
-					n->indent = $7;
+					n->version = $7;
+					n->xmldeclaration = $8;
+					n->indent = $9;
 					n->location = @1;
 					$$ = (Node *) n;
 				}
@@ -16432,6 +16436,21 @@ xml_indent_option: INDENT							{ $$ = true; }
 			| /*EMPTY*/								{ $$ = false; }
 		;
 
+xmlserialize_version:
+			VERSION_P Sconst		{ $$ = $2; }
+		|	VERSION_P NULL_P		{ $$ = NULL; }
+		;
+
+opt_xml_declaration_version:
+			xmlserialize_version	{ $$ = $1; }
+			| /*EMPTY*/				{ $$ = NULL; }
+		;
+
+opt_xml_declaration_option: INCLUDING XMLDECLARATION	{ $$ = XMLSERIALIZE_INCLUDING_XMLDECLARATION; }
+			| EXCLUDING XMLDECLARATION					{ $$ = XMLSERIALIZE_EXCLUDING_XMLDECLARATION; }
+			| /*EMPTY*/									{ $$ = XMLSERIALIZE_NO_XMLDECLARATION_OPTION; }
+		;
+
 xml_whitespace_option: PRESERVE WHITESPACE_P		{ $$ = true; }
 			| STRIP_P WHITESPACE_P					{ $$ = false; }
 			| /*EMPTY*/								{ $$ = false; }
@@ -18126,6 +18145,7 @@ unreserved_keyword:
 			| WRAPPER
 			| WRITE
 			| XML_P
+			| XMLDECLARATION
 			| YEAR_P
 			| YES_P
 			| ZONE
@@ -18784,6 +18804,7 @@ bare_label_keyword:
 			| XML_P
 			| XMLATTRIBUTES
 			| XMLCONCAT
+			| XMLDECLARATION
 			| XMLELEMENT
 			| XMLEXISTS
 			| XMLFOREST

src/backend/parser/parse_expr.c

@@ -2502,6 +2502,8 @@ transformXmlSerialize(ParseState *pstate, XmlSerialize *xs)
 
 	xexpr->xmloption = xs->xmloption;
 	xexpr->indent = xs->indent;
+	xexpr->version = xs->version;
+	xexpr->xmldeclaration = xs->xmldeclaration;
 	xexpr->location = xs->location;
 	/* We actually only need these to be able to parse back the expression. */
 	xexpr->type = targetType;

src/backend/utils/adt/ruleutils.c

@@ -10232,6 +10232,15 @@ get_rule_expr(Node *node, deparse_context *context,
 					appendStringInfo(buf, " AS %s",
 									 format_type_with_typemod(xexpr->type,
 															  xexpr->typmod));
+
+					if (xexpr->version)
+						appendStringInfo(buf, " VERSION '%s'", xexpr->version);
+
+					if (xexpr->xmldeclaration == XMLSERIALIZE_INCLUDING_XMLDECLARATION)
+						appendStringInfoString(buf, " INCLUDING XMLDECLARATION");
+					else if (xexpr->xmldeclaration == XMLSERIALIZE_EXCLUDING_XMLDECLARATION)
+						appendStringInfoString(buf, " EXCLUDING XMLDECLARATION");
+
 					if (xexpr->indent)
 						appendStringInfoString(buf, " INDENT");
 					else