MEM_RefCountPtr.h

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/*
 * $Id: MEM_RefCountPtr.h 35156 2011-02-25 11:47:18Z jesterking $
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
 * All rights reserved.
 *
 * The Original Code is: all of this file.
 *
 * Contributor(s): none yet.
 *
 * ***** END GPL LICENSE BLOCK *****
 */

#ifndef NAN_INCLUDED_MEM_RefCountPtr_h
#define NAN_INCLUDED_MEM_RefCountPtr_h

#include <stdlib.h> // for NULL !

class MEM_RefCountable {
private :

        mutable int m_count;

protected :

        MEM_RefCountable (
        ) :
                m_count (0)
        {
        };

        MEM_RefCountable (
                const MEM_RefCountable &
        ) :
                m_count (0)
        {
        }

public :

                void
        IncRef(
        ) const {
                m_count++;
        }

                int
        DecRef(
        ) {
                return (--m_count);
        }

        ~MEM_RefCountable(
        ) {
                //nothing to do
        }
};

template
        < class T >
class MEM_RefCountPtr {

public :

        MEM_RefCountPtr(
                const MEM_RefCountPtr &rhs
        ) : m_val (NULL) {
                ShareOwnership(rhs.m_val);
        }

        MEM_RefCountPtr(
                const T* val
        ) :
                m_val (NULL)
        {
                ShareOwnership(val);
        }

        MEM_RefCountPtr(
        ) :
                m_val (NULL)
        {
        }

        operator T * () const {
                return m_val;
        }


        MEM_RefCountPtr & operator=(
                const MEM_RefCountPtr &rhs
        ) {
                if (this->m_val != rhs.m_val) {
                        ReleaseOwnership();
                        ShareOwnership(rhs.m_val);
                }
                return *this;
        }

        T * operator->() const {
                return m_val;
        }

                T&
        Ref(
        ) {
                return *m_val;
        }


        ~MEM_RefCountPtr(
        ) {
                ReleaseOwnership();
        }

private :
        
        T * m_val;

                void
        ShareOwnership(
                const T * val
        ) {
                if (val != NULL) {
                        val->IncRef();
                }
                m_val = const_cast<T *>(val);
        }
                
                void
        ReleaseOwnership(
        ) {
                if (m_val) {
                        if (m_val->DecRef() == 0) {
                                delete(m_val);
                                m_val = NULL;
                        }
                }
        }

};

#endif