/*

 * 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 WorkItem_h

#define WorkItem_h

#include <wtf/PassOwnPtr.h>

class WorkItem {

public:

    template<typename C> 

    static PassOwnPtr<WorkItem> create(C*, void (C::*)());

    template<typename C, typename T0, typename T1>

    static PassOwnPtr<WorkItem> create(C*, void (C::*)(T0, T1), T0, T1);

    virtual ~WorkItem() { }

    virtual void execute() = 0;

protected:

    WorkItem() { }

private:

    WorkItem(const WorkItem&);

    WorkItem& operator=(const WorkItem&);

};

template <typename C>

class MemberFunctionWorkItem0 : private WorkItem {

    // We only allow WorkItem to create this.

    friend class WorkItem;

    typedef void (C::*FunctionType)();

    MemberFunctionWorkItem0(C* ptr, FunctionType function)

        : m_ptr(ptr)

        , m_function(function)

    {

        m_ptr->ref();

    }

    ~MemberFunctionWorkItem0()

    {

        m_ptr->deref();

    }

    void execute()

    {

        (m_ptr->*m_function)();

    }

    C* m_ptr;

    FunctionType m_function;

};

template<typename C, typename T0, typename T1>

class MemberFunctionWorkItem2 : private WorkItem {

    // We only allow WorkItem to create this.

    friend class WorkItem;

    typedef void (C::*FunctionType)(T0, T1);

    MemberFunctionWorkItem2(C* ptr, FunctionType function, T0 t0, T1 t1)

        : m_ptr(ptr)

        , m_function(function)

        , m_t0(t0)

        , m_t1(t1)

    {

        m_ptr->ref();

    }

    ~MemberFunctionWorkItem2()

    {

        m_ptr->deref();

    }

    void execute()

    {

        (m_ptr->*m_function)(m_t0, m_t1);

    }

    C* m_ptr;

    FunctionType m_function;

    T0 m_t0;

    T1 m_t1;

};

template<typename C>

PassOwnPtr<WorkItem> WorkItem::create(C* ptr, void (C::*function)())

{

    return adoptPtr(static_cast<WorkItem*>(new MemberFunctionWorkItem0<C>(ptr, function)));

}

template<typename C, typename T0, typename T1>

PassOwnPtr<WorkItem> WorkItem::create(C* ptr, void (C::*function)(T0, T1), T0 t0, T1 t1)

{

    return adoptPtr(static_cast<WorkItem*>(new MemberFunctionWorkItem2<C, T0, T1>(ptr, function, t0, t1)));

}

#endif // WorkItem_h