/*
 * Copyright (C) 2010 Apple 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:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS 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 APPLE INC. OR ITS 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 GenericCallback_h
#define GenericCallback_h

#include "WKAPICast.h"
#include <wtf/PassRefPtr.h>
#include <wtf/RefCounted.h>

namespace WebKit {

template<typename APIReturnValueType, typename InternalReturnValueType = typename APITypeInfo<APIReturnValueType>::ImplType>
class GenericCallback : public RefCounted<GenericCallback<APIReturnValueType, InternalReturnValueType> > {
public:
    typedef void (*CallbackFunction)(APIReturnValueType, void*);
    typedef void (*CallbackDisposeFunction)(void*);

    static PassRefPtr<GenericCallback> create(void* context, CallbackFunction callback, CallbackDisposeFunction disposeCallback)
    {
        return adoptRef(new GenericCallback(context, callback, disposeCallback));
    }

    ~GenericCallback()
    {
        ASSERT(!m_callback);
    }

    void performCallbackWithReturnValue(InternalReturnValueType returnValue)
    {
        ASSERT(m_callback);

        m_callback(toRef(returnValue), m_context);

        m_callback = 0;
        m_disposeCallback = 0;
    }
    
    void invalidate()
    {
        ASSERT(m_callback);

        m_disposeCallback(m_context);

        m_callback = 0;
        m_disposeCallback = 0;
    }

    uint64_t callbackID() const { return m_callbackID; }

private:
    static uint64_t generateCallbackID()
    {
        static uint64_t uniqueCallbackID = 1;
        return uniqueCallbackID++;
    }

    GenericCallback(void* context, CallbackFunction callback, CallbackDisposeFunction disposeCallback)
        : m_context(context)
        , m_callback(callback)
        , m_disposeCallback(disposeCallback)
        , m_callbackID(generateCallbackID())
    {
    }

    void* m_context;
    CallbackFunction m_callback;
    CallbackDisposeFunction m_disposeCallback;
    uint64_t m_callbackID;
};

} // namespace WebKit

#endif // GenericCallback_h