Resources/ResourcePtr.hpp

Go to the documentation of this file.

//
// Thor C++ Library
// Copyright (c) 2011 Jan Haller
// 
// This software is provided 'as-is', without any express or implied
// warranty. In no event will the authors be held liable for any damages
// arising from the use of this software.
// 
// Permission is granted to anyone to use this software for any purpose,
// including commercial applications, and to alter it and redistribute it
// freely, subject to the following restrictions:
// 
// 1. The origin of this software must not be misrepresented; you must not
//    claim that you wrote the original software. If you use this software
//    in a product, an acknowledgment in the product documentation would be
//    appreciated but is not required.
// 
// 2. Altered source versions must be plainly marked as such, and must not be
//    misrepresented as being the original software.
// 
// 3. This notice may not be removed or altered from any source distribution.
//


#ifndef THOR_RESOURCEPTR_HPP
#define THOR_RESOURCEPTR_HPP

#include <Thor/Detail/ResourceSlotBase.hpp>
#include <Thor/Detail/SafeBoolIdiom.hpp>
#include <Thor/Detail/Metaprogramming.hpp>
#include <Thor/Config.hpp>

#include THOR_TR1_HEADER(type_traits)
#include <algorithm>
#include <cassert>


namespace thor
{


template <class Resource>
class ResourcePtr
{
    // ---------------------------------------------------------------------------------------------------------------------------
    // Private types
    private:
        // Resource without const qualifier
        typedef typename std::tr1::remove_const<Resource>::type         MutableResource;

        // ResourceSlot with the same const qualification as Resource
        typedef typename detail::Conditional<
            std::tr1::is_const<Resource>::value,
            const detail::ResourceSlotBase<MutableResource>, 
            detail::ResourceSlotBase<MutableResource> >::Type           ResourceSlot;


    // ---------------------------------------------------------------------------------------------------------------------------
    // Public member functions
    public:
                                ResourcePtr();
    
                                ResourcePtr(const ResourcePtr& origin);
                                
        template <class Resource2>
                                ResourcePtr(const ResourcePtr<Resource2>& origin);

        ResourcePtr&            operator= (const ResourcePtr& origin);


        template <class Resource2>
        ResourcePtr&            operator= (const ResourcePtr<Resource2>& origin);

                                ~ResourcePtr();

        void                    Swap(ResourcePtr& other);

        void                    Reset();
        
                                operator THOR_DETAIL SafeBool() const;

        Resource&               operator* () const;
        
        Resource*               operator-> () const;


    // ---------------------------------------------------------------------------------------------------------------------------
    // Implementation details
    public:
        // Constructor from resource slot, internally used by ResourceManager
        explicit                ResourcePtr(ResourceSlot& slot);

    
    // ---------------------------------------------------------------------------------------------------------------------------
    // Private member functions
    private:        // Increases the reference counter, if required.
        void                    IncRef();
        
        // Decreases the reference counter, if required.    
        void                    DecRef();
        
        // Sets the internal pointer to NULL without affecting the reference counter.
        void                    Invalidate();
        

    // ---------------------------------------------------------------------------------------------------------------------------
    // Private variables
    private:
        ResourceSlot*           mSlot;


    // ---------------------------------------------------------------------------------------------------------------------------
    // Friends
    template <class Resource1, class Resource2>
    friend bool operator== (const ResourcePtr<Resource1>& lhs, const ResourcePtr<Resource2>& rhs);
    
    template <class Resource2>
    friend class ResourcePtr;
    
    friend class detail::ResourceSlotBase<MutableResource>;
};

template <class Resource>
void swap(ResourcePtr<Resource>& lhs, ResourcePtr<Resource>& rhs);

template <class Resource1, class Resource2>
bool operator== (const ResourcePtr<Resource1>& lhs, const ResourcePtr<Resource2>& rhs);

template <class Resource1, class Resource2>
bool operator!= (const ResourcePtr<Resource1>& lhs, const ResourcePtr<Resource2>& rhs);


} // namespace thor

#include <Thor/Detail/ResourcePtr.inl>
#endif // THOR_RESOURCEPTR_HPP