/*

 * Copyright (C) 2008 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. ``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

 * 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 CachedResourceHandle_h

#define CachedResourceHandle_h

#include "CachedResource.h"

namespace WebCore {

    class CachedResourceHandleBase {

    public:

        ~CachedResourceHandleBase() { if (m_resource) m_resource->unregisterHandle(this); }

        CachedResource* get() const { return m_resource; }

        bool operator!() const { return !m_resource; }

        // This conversion operator allows implicit conversion to bool but not to other integer types.

        // Parenthesis is needed for winscw compiler to resolve class qualifier in this case.

        typedef CachedResource* (CachedResourceHandleBase::*UnspecifiedBoolType);

        operator UnspecifiedBoolType() const { return m_resource ? &CachedResourceHandleBase::m_resource : 0; }

    protected:

        CachedResourceHandleBase() : m_resource(0) {}

        CachedResourceHandleBase(CachedResource* res) { m_resource = res; if (m_resource) m_resource->registerHandle(this); }

        CachedResourceHandleBase(const CachedResourceHandleBase& o) : m_resource(o.m_resource) { if (m_resource) m_resource->registerHandle(this); }

        void setResource(CachedResource*);

    private:

        CachedResourceHandleBase& operator=(const CachedResourceHandleBase&) { return *this; } 

        friend class CachedResource;

        CachedResource* m_resource;

    };

    template <class R> class CachedResourceHandle : public CachedResourceHandleBase {

    public: 

        CachedResourceHandle() { }

        CachedResourceHandle(R* res);

        CachedResourceHandle(const CachedResourceHandle<R>& o) : CachedResourceHandleBase(o) { }

        R* get() const { return reinterpret_cast<R*>(CachedResourceHandleBase::get()); }

        R* operator->() const { return get(); }

        CachedResourceHandle& operator=(R* res) { setResource(res); return *this; } 

        CachedResourceHandle& operator=(const CachedResourceHandle& o) { setResource(o.get()); return *this; }

        bool operator==(const CachedResourceHandleBase& o) const { return get() == o.get(); }

        bool operator!=(const CachedResourceHandleBase& o) const { return get() != o.get(); }

    };

    // Don't inline for winscw compiler to prevent the compiler aggressively resolving

    // the base class of R* when CachedResourceHandler<T>(R*) is inlined.  The bug is

    // reported at: https://xdabug001.ext.nokia.com/bugzilla/show_bug.cgi?id=9812.

    template <class R>

#if !COMPILER(WINSCW)

    inline

#endif

    CachedResourceHandle<R>::CachedResourceHandle(R* res) : CachedResourceHandleBase(res) 

    {

    }

    template <class R, class RR> bool operator==(const CachedResourceHandle<R>& h, const RR* res) 

    { 

        return h.get() == res; 

    }

    template <class R, class RR> bool operator==(const RR* res, const CachedResourceHandle<R>& h) 

    { 

        return h.get() == res; 

    }

    template <class R, class RR> bool operator!=(const CachedResourceHandle<R>& h, const RR* res) 

    { 

        return h.get() != res; 

    }

    template <class R, class RR> bool operator!=(const RR* res, const CachedResourceHandle<R>& h) 

    { 

        return h.get() != res; 

    }

}

#endif