ElementWrapper.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 ROCKETCOREPYTHONELEMENTWRAPPER_H
00029 #define ROCKETCOREPYTHONELEMENTWRAPPER_H
00030 
00031 namespace Rocket {
00032 namespace Core {
00033 namespace Python {
00034 
00045 template <typename T>
00046 class ElementWrapper : public T
00047 {
00048 public:
00049         ElementWrapper( PyObject* self, const char* tag ) : self( self ), T( tag )
00050         {
00051                 // Force remove reference, to reduce the count to 0 as python has instanced
00052                 // this object. If the call originally came from C++ (PyBRElementInstancer)
00053                 // then it will add its own reference
00054                 T::RemoveReference();
00055 
00056                 // If the C++ reference count is not 0 at this point, it means additional references have been added
00057                 // during the classes constructor. We have to propogate these references into python.
00058                 for (int i = 0; i < this->T::GetReferenceCount(); i++)
00059                         Py_INCREF(self);
00060         }
00061         virtual ~ElementWrapper() {}
00062 
00064         virtual void* GetScriptObject() const { return self; }
00065 
00066         // Propogate add ref's into python
00067         virtual void AddReference()
00068         {
00069                 Py_INCREF( self );
00070 
00071                 T::AddReference();
00072         }
00073 
00074         // Propogate remove ref's into python
00075         virtual void RemoveReference()
00076         {
00077                 T::RemoveReference();
00078 
00079                 Py_DECREF( self );
00080         }
00081 
00082         virtual void OnReferenceDeactivate()
00083         {
00084                 // Ignore reference deactivated
00085         }
00086 
00087 private:
00088         // Python representation of this object
00089         PyObject* self;
00090 };
00091 
00092 }
00093 }
00094 }
00095 
00096 #endif