/*

 * Copyright (C) 2009 Google Inc. All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions are

 * met:

 *

 *     * Redistributions of source code must retain the above copyright

 * notice, this list of conditions and the following disclaimer.

 *     * Redistributions in binary form must reproduce the above

 * copyright notice, this list of conditions and the following disclaimer

 * in the documentation and/or other materials provided with the

 * distribution.

 *     * Neither the name of Google Inc. nor the names of its

 * contributors may be used to endorse or promote products derived from

 * this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

#ifndef OwnHandle_h

#define OwnHandle_h

#include <v8.h>

namespace WebCore {

    template<typename T>

    class OwnHandle {

    public:

        OwnHandle() { }

        explicit OwnHandle(v8::Handle<T> handle) : m_handle(v8::Persistent<T>::New(handle)) { }

        ~OwnHandle() { clear(); }

        v8::Handle<T> get() const { return m_handle; }

        void set(v8::Handle<T> handle) { clear(); m_handle = v8::Persistent<T>::New(handle); }

        // Note: This is clear in the OwnPtr sense, not the v8::Handle sense.

        void clear()

        {

            if (m_handle.IsEmpty())

                return;

            if (m_handle.IsWeak())

                m_handle.ClearWeak();

            m_handle.Dispose();

            m_handle.Clear();

        }

        // Make the underlying handle weak.  The client doesn't get a callback,

        // we just make the handle empty.

        void makeWeak()

        {

            if (m_handle.IsEmpty())

                return;

            m_handle.MakeWeak(this, &OwnHandle<T>::weakCallback);

        }

    private:

        static void weakCallback(v8::Persistent<v8::Value> object, void* ownHandle)

        {

            OwnHandle<T>* handle = static_cast<OwnHandle<T>*>(ownHandle);

            handle->clear();

        }

        v8::Persistent<T> m_handle;

    };

} // namespace WebCore

#endif // OwnHandle_h