OgreSharedPtr.h

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/*
-----------------------------------------------------------------------------
This source file is part of OGRE
    (Object-oriented Graphics Rendering Engine)
For the latest info, see http://www.ogre3d.org/

Copyright (c) 2000-2005 The OGRE Team
Also see acknowledgements in Readme.html

This program 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 of the License, or (at your option) any later
version.

This program 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 program; if not, write to the Free Software Foundation, Inc., 59 Temple
Place - Suite 330, Boston, MA 02111-1307, USA, or go to
http://www.gnu.org/copyleft/lesser.txt.
-----------------------------------------------------------------------------
*/
#ifndef __SharedPtr_H__
#define __SharedPtr_H__

#include "OgrePrerequisites.h"

namespace Ogre {

    template<class T> class SharedPtr {
    protected:
        T* pRep;
        unsigned int* pUseCount;
    public:
        OGRE_AUTO_SHARED_MUTEX // public to allow external locking
        SharedPtr() : pRep(0), pUseCount(0) {}
        explicit SharedPtr(T* rep) : pRep(rep), pUseCount(new unsigned int(1)) 
        {
            OGRE_NEW_AUTO_SHARED_MUTEX
        }
        SharedPtr(const SharedPtr& r) 
        {
            // lock & copy other mutex pointer
            OGRE_LOCK_MUTEX(*r.OGRE_AUTO_MUTEX_NAME)
            OGRE_COPY_AUTO_SHARED_MUTEX(r.OGRE_AUTO_MUTEX_NAME)
            pRep = r.pRep;
            pUseCount = r.pUseCount; 
            // Handle zero pointer gracefully to manage STL containers
            if(pUseCount)
            {
                ++(*pUseCount); 
            }
        }
        SharedPtr& operator=(const SharedPtr& r) {
            if (pRep == r.pRep)
                return *this;
            release();
            // lock & copy other mutex pointer
            OGRE_LOCK_MUTEX(*r.OGRE_AUTO_MUTEX_NAME)
            OGRE_COPY_AUTO_SHARED_MUTEX(r.OGRE_AUTO_MUTEX_NAME)
            pRep = r.pRep;
            pUseCount = r.pUseCount;
            if (pUseCount)
            {
                ++(*pUseCount);
            }
            return *this;
        }
        virtual ~SharedPtr() {
            release();
        }


        inline T& operator*() const { assert(pRep); return *pRep; }
        inline T* operator->() const { assert(pRep); return pRep; }
        inline T* get() const { return pRep; }

        void bind(T* rep) {
            assert(!pRep && !pUseCount);
            OGRE_NEW_AUTO_SHARED_MUTEX
            OGRE_LOCK_AUTO_SHARED_MUTEX
            pUseCount = new unsigned int(1);
            pRep = rep;
        }

        inline bool unique() const { assert(pUseCount); OGRE_LOCK_AUTO_SHARED_MUTEX return *pUseCount == 1; }
        inline unsigned int useCount() const { assert(pUseCount); OGRE_LOCK_AUTO_SHARED_MUTEX return *pUseCount; }
        inline unsigned int* useCountPointer() const { return pUseCount; }

        inline T* getPointer() const { return pRep; }

        inline bool isNull(void) const { return pRep == 0; }

        inline void setNull(void) { 
            if (pRep)
            {
                // can't scope lock mutex before release incase deleted
                release();
                pRep = 0;
                pUseCount = 0;
                OGRE_COPY_AUTO_SHARED_MUTEX(0)
            }
        }

    protected:

        inline void release(void) {
            bool destroyThis = false;
            {
                // lock own mutex in limited scope (must unlock before destroy)
                OGRE_LOCK_AUTO_SHARED_MUTEX
                if (pUseCount)
                {
                    if (--(*pUseCount) == 0) 
                    {
                        destroyThis = true;
                    }
                }
            }
            if (destroyThis)
                destroy();
        }

        virtual void destroy(void)
        {
            // IF YOU GET A CRASH HERE, YOU FORGOT TO FREE UP POINTERS
            // BEFORE SHUTTING OGRE DOWN
            // Use setNull() before shutdown or make sure your pointer goes
            // out of scope before OGRE shuts down to avoid this.
            delete pRep;
            delete pUseCount;
            OGRE_DELETE_AUTO_SHARED_MUTEX
        }
    };

    template<class T, class U> inline bool operator==(SharedPtr<T> const& a, SharedPtr<U> const& b)
    {
        return a.get() == b.get();
    }

    template<class T, class U> inline bool operator!=(SharedPtr<T> const& a, SharedPtr<U> const& b)
    {
        return a.get() != b.get();
    }

}

#endif

---

Copyright © 2000-2005 by The OGRE Team

This work is licensed under a Creative Commons Attribution-ShareAlike 2.5 License.
Last modified Sun Mar 12 14:37:49 2006