/*
 *  This file is part of the KDE libraries
 *  Copyright (C) 2005 Apple Computer, Inc.
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Library General Public
 *  License as published by the Free Software Foundation; either
 *  version 2 of the License, or (at your option) any later version.
 *
 *  This library 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
 *  Library General Public License for more details.
 *
 *  You should have received a copy of the GNU Library General Public License
 *  along with this library; see the file COPYING.LIB.  If not, write to
 *  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 *  Boston, MA 02110-1301, USA.
 *
 */

#ifndef WTF_ListRefPtr_h
#define WTF_ListRefPtr_h

#include <wtf/RefPtr.h>

namespace WTF
{

// Specialized version of RefPtr designed for use in singly-linked lists.
// Derefs the list iteratively to avoid recursive derefing that can overflow the stack.
template <typename T> class ListRefPtr : public RefPtr<T>
{
public:
    ListRefPtr() : RefPtr<T>() {}
    ListRefPtr(T *ptr) : RefPtr<T>(ptr) {}
    ListRefPtr(const RefPtr<T> &o) : RefPtr<T>(o) {}
    // see comment in PassRefPtr.h for why this takes const reference
    template <typename U> ListRefPtr(const PassRefPtr<U> &o) : RefPtr<T>(o) {}

    ~ListRefPtr()
    {
        RefPtr<T> reaper = this->release();
        while (reaper && reaper->refcount() == 1) {
            reaper = reaper->releaseNext();    // implicitly protects reaper->next, then derefs reaper
        }
    }

    ListRefPtr &operator=(T *optr)
    {
        RefPtr<T>::operator=(optr);
        return *this;
    }
    ListRefPtr &operator=(const RefPtr<T> &o)
    {
        RefPtr<T>::operator=(o);
        return *this;
    }
    ListRefPtr &operator=(const PassRefPtr<T> &o)
    {
        RefPtr<T>::operator=(o);
        return *this;
    }
    template <typename U> ListRefPtr &operator=(const RefPtr<U> &o)
    {
        RefPtr<T>::operator=(o);
        return *this;
    }
    template <typename U> ListRefPtr &operator=(const PassRefPtr<U> &o)
    {
        RefPtr<T>::operator=(o);
        return *this;
    }
};

} // namespace WTF

using WTF::ListRefPtr;

#endif // WTF_ListRefPtr_h

