Add XML name registry.

Allows users to add new types to XML styles.

include/mapnik/formatting/registry.hpp

@@ -0,0 +1,57 @@
+/*****************************************************************************
+ *
+ * This file is part of Mapnik (c++ mapping toolkit)
+ *
+ * Copyright (C) 2012 Artem Pavlenko
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ *****************************************************************************/
+#ifndef FORMATTING_REGISTRY_HPP
+#define FORMATTING_REGISTRY_HPP
+
+// mapnik
+#include <mapnik/utils.hpp>
+#include <mapnik/formatting/base.hpp>
+
+// boost
+#include <boost/utility.hpp>
+
+// stl
+#include <string>
+#include <map>
+
+namespace mapnik
+{
+namespace formatting
+{
+
+typedef node_ptr (*from_xml_function_ptr)(boost::property_tree::ptree const& xml);
+
+class registry : public singleton<registry, CreateStatic>,
+        private boost::noncopyable
+{
+public:
+    registry();
+    ~registry() {}
+    void register_name(std::string name, from_xml_function_ptr ptr, bool overwrite=false);
+    node_ptr from_xml(std::string name, boost::property_tree::ptree const& xml);
+private:
+    std::map<std::string, from_xml_function_ptr> map_;
+};
+
+} //ns formatting
+} //ns mapnik
+#endif // FORMATTING_REGISTRY_HPP

src/build.py

@@ -170,6 +170,7 @@ source = Split(
     formatting/list.cpp
     formatting/text.cpp
     formatting/format.cpp
+    formatting/registry.cpp
     """   
     )
 

src/formatting/base.cpp

@@ -22,9 +22,7 @@
 // mapnik
 #include <mapnik/formatting/base.hpp>
 #include <mapnik/formatting/list.hpp>
-#include <mapnik/formatting/text.hpp>
-#include <mapnik/formatting/expression.hpp>
-#include <mapnik/formatting/format.hpp>
+#include <mapnik/formatting/registry.hpp>
 
 // boost
 #include <boost/property_tree/ptree.hpp>
@@ -47,16 +45,11 @@ node_ptr node::from_xml(boost::property_tree::ptree const& xml)
     boost::property_tree::ptree::const_iterator itr = xml.begin();
     boost::property_tree::ptree::const_iterator end = xml.end();
     for (; itr != end; ++itr) {
-        node_ptr n;
-        if (itr->first == "<xmltext>") {
-            n = text_node::from_xml(itr->second);
-        } else if (itr->first == "Format") {
-            n = format_node::from_xml(itr->second);
-        } else if (itr->first == "ExpressionFormat") {
-            n = expression_format::from_xml(itr->second);
-        } else if (itr->first != "<xmlcomment>" && itr->first != "<xmlattr>" && itr->first != "Placement") {
-            throw config_error("Unknown item " + itr->first);
+        if (itr->first == "<xmlcomment>" || itr->first == "<xmlattr>" || itr->first == "Placement")
+        {
+            continue;
         }
+        node_ptr n = registry::instance()->from_xml(itr->first, itr->second);
         if (n) list->push_back(n);
     }
     if (list->get_children().size() == 1) {

src/formatting/registry.cpp

@@ -0,0 +1,56 @@
+/*****************************************************************************
+ *
+ * This file is part of Mapnik (c++ mapping toolkit)
+ *
+ * Copyright (C) 2012 Artem Pavlenko
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ *****************************************************************************/
+// mapnik
+#include <mapnik/formatting/registry.hpp>
+#include <mapnik/formatting/text.hpp>
+#include <mapnik/formatting/format.hpp>
+#include <mapnik/formatting/expression.hpp>
+
+namespace mapnik
+{
+namespace formatting
+{
+
+registry::registry()
+{
+    register_name("<xmltext>", &text_node::from_xml);
+    register_name("Format", &format_node::from_xml);
+    register_name("ExpressionFormat", &expression_format::from_xml);
+}
+
+void registry::register_name(std::string name, from_xml_function_ptr ptr, bool overwrite)
+{
+    if (overwrite) {
+        map_[name] = ptr;
+    } else {
+        map_.insert(make_pair(name, ptr));
+    }
+}
+
+node_ptr registry::from_xml(std::string name, const boost::property_tree::ptree &xml)
+{
+    std::map<std::string, from_xml_function_ptr>::const_iterator itr = map_.find(name);
+    if (itr == map_.end())  throw config_error("Unknown element '" + name + "'");
+    return itr->second(xml);
+}
+} //ns formatting
+} //ns mapnik