[*_restore] Use a little wrapper class for the expat XML_Parser to ensure it gets destroyed.

base/xml_utils.h

@@ -3,6 +3,7 @@
 
 #include <boost/lexical_cast.hpp>
 #include <boost/optional.hpp>
+#include <expat.h>
 #include <map>
 
 using namespace std;
@@ -10,6 +11,29 @@ using namespace std;
 //----------------------------------------------------------------
 
 namespace xml_utils {
+	// Simple wrapper to ensure the parser gets freed if an exception
+	// is thrown during parsing.
+	class xml_parser {
+	public:
+		xml_parser()
+			: parser_(XML_ParserCreate(NULL)) {
+
+			if (!parser_)
+				throw runtime_error("couldn't create xml parser");
+		}
+
+		~xml_parser() {
+			XML_ParserFree(parser_);
+		}
+
+		XML_Parser get_parser() {
+			return parser_;
+		}
+
+	private:
+		XML_Parser parser_;
+        };
+
 	typedef std::map<std::string, std::string> attributes;
 
 	void build_attributes(attributes &a, char const **attr);