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/*
* 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 <wtf/Forward.h>
namespace WebCore {
class CachedResource;
class CachedResourceHandleBase {
public:
~CachedResourceHandleBase();
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.
typedef CachedResource* CachedResourceHandleBase::*UnspecifiedBoolType;
operator UnspecifiedBoolType() const { return m_resource ? &CachedResourceHandleBase::m_resource : 0; }
protected:
CachedResourceHandleBase();
CachedResourceHandleBase(CachedResource*);
CachedResourceHandleBase(const CachedResourceHandleBase&);
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) : CachedResourceHandleBase(res) { }
CachedResourceHandle(const CachedResourceHandle<R>& o) : CachedResourceHandleBase(o) { }
template<typename U> CachedResourceHandle(const CachedResourceHandle<U>& o) : CachedResourceHandleBase(o.get()) { }
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; }
template<typename U> CachedResourceHandle& operator=(const CachedResourceHandle<U>& 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(); }
};
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;
}
} // namespace WebCore
#endif // CachedResourceHandle
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