ElementInstancer.h

00001 /*
00002  * This source file is part of libRocket, the HTML/CSS Interface Middleware
00003  *
00004  * For the latest information, see http://www.librocket.com
00005  *
00006  * Copyright (c) 2008-2010 CodePoint Ltd, Shift Technology Ltd
00007  *
00008  * Permission is hereby granted, free of charge, to any person obtaining a copy
00009  * of this software and associated documentation files (the "Software"), to deal
00010  * in the Software without restriction, including without limitation the rights
00011  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
00012  * copies of the Software, and to permit persons to whom the Software is
00013  * furnished to do so, subject to the following conditions:
00014  *
00015  * The above copyright notice and this permission notice shall be included in
00016  * all copies or substantial portions of the Software.
00017  * 
00018  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00019  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00020  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
00021  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00022  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00023  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
00024  * THE SOFTWARE.
00025  *
00026  */
00027 
00028 #ifndef ROCKETCOREPYTHONELEMENTINSTANCER_H
00029 #define ROCKETCOREPYTHONELEMENTINSTANCER_H
00030 
00031 #include <Rocket/Core/String.h>
00032 #include <Rocket/Core/XMLParser.h>
00033 #include <Rocket/Core/Python/Python.h>
00034 #include <Rocket/Core/Element.h>
00035 #include <Rocket/Core/ElementInstancer.h>
00036 #include <Rocket/Core/Python/Header.h>
00037 
00038 namespace Rocket {
00039 namespace Core {
00040 namespace Python {
00041 
00053 class ElementInstancer : public Rocket::Core::ElementInstancer
00054 {
00055 public:
00056         ElementInstancer(PyObject* _class_definition)
00057         {
00058                 class_definition = _class_definition;
00059                 Py_INCREF(class_definition);
00060         }
00061         virtual ~ElementInstancer()
00062         {
00063                 Py_DECREF(class_definition);
00064         }
00065 
00069         virtual Element* InstanceElement(Element* ROCKET_UNUSED(parent), const Rocket::Core::String& tag, const Rocket::Core::XMLAttributes& ROCKET_UNUSED(attributes))
00070         {
00071                 // Build the arguments
00072                 PyObject* args = PyTuple_New(1);
00073                 PyTuple_SetItem(args, 0, PyString_FromString(tag.CString()));
00074 
00075                 PyObject* instance = PyObject_CallObject(class_definition, args);
00076                 Py_DECREF(args);
00077 
00078                 // Check the instance was created successfully
00079                 if (instance == NULL)
00080                 {
00081                         PyErr_Print();
00082                         return NULL;
00083                 }
00084 
00085                 Element* element = python::extract<Element*>(python::object(python::handle<>(python::borrowed(instance))));     
00086 
00087                 // Need to switch the Python reference count to a true C++ reference count.
00088                 element->AddReference(); // Adds to C++ and Python reference counts.
00089                 Py_DECREF( instance );   // Removes from Python.
00090 
00091                 return element;
00092         }
00093 
00096         virtual void ReleaseElement(Element* ROCKET_UNUSED(element))
00097         {
00098                 // Never release Python elements, Python will manage this for us.
00099         }
00100 
00102         virtual void Release()
00103         {
00104                 delete this;
00105         }
00106 
00107 private:
00108         PyObject* class_definition;
00109 };
00110 
00111 }
00112 }
00113 }
00114 
00115 #endif