1/* 2 * Copyright (C) 2008 Apple Inc. All Rights Reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY 14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR 17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY 21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24 */ 25 26#ifndef CachedResourceHandle_h 27#define CachedResourceHandle_h 28 29#include <wtf/Forward.h> 30 31namespace WebCore { 32 33class CachedResource; 34 35class CachedResourceHandleBase { 36public: 37 ~CachedResourceHandleBase(); 38 39 CachedResource* get() const { return m_resource; } 40 41 bool operator!() const { return !m_resource; } 42 43 // This conversion operator allows implicit conversion to bool but not to other integer types. 44 typedef CachedResource* CachedResourceHandleBase::*UnspecifiedBoolType; 45 operator UnspecifiedBoolType() const { return m_resource ? &CachedResourceHandleBase::m_resource : 0; } 46 47protected: 48 CachedResourceHandleBase(); 49 CachedResourceHandleBase(CachedResource*); 50 CachedResourceHandleBase(const CachedResourceHandleBase&); 51 52 void setResource(CachedResource*); 53 54private: 55 CachedResourceHandleBase& operator=(const CachedResourceHandleBase&) { return *this; } 56 57 friend class CachedResource; 58 59 CachedResource* m_resource; 60}; 61 62template <class R> class CachedResourceHandle : public CachedResourceHandleBase { 63public: 64 CachedResourceHandle() { } 65 CachedResourceHandle(R* res) : CachedResourceHandleBase(res) { } 66 CachedResourceHandle(const CachedResourceHandle<R>& o) : CachedResourceHandleBase(o) { } 67 template<typename U> CachedResourceHandle(const CachedResourceHandle<U>& o) : CachedResourceHandleBase(o.get()) { } 68 69 R* get() const { return reinterpret_cast<R*>(CachedResourceHandleBase::get()); } 70 R* operator->() const { return get(); } 71 72 CachedResourceHandle& operator=(R* res) { setResource(res); return *this; } 73 CachedResourceHandle& operator=(const CachedResourceHandle& o) { setResource(o.get()); return *this; } 74 template<typename U> CachedResourceHandle& operator=(const CachedResourceHandle<U>& o) { setResource(o.get()); return *this; } 75 76 bool operator==(const CachedResourceHandleBase& o) const { return get() == o.get(); } 77 bool operator!=(const CachedResourceHandleBase& o) const { return get() != o.get(); } 78}; 79 80template <class R, class RR> bool operator==(const CachedResourceHandle<R>& h, const RR* res) 81{ 82 return h.get() == res; 83} 84template <class R, class RR> bool operator==(const RR* res, const CachedResourceHandle<R>& h) 85{ 86 return h.get() == res; 87} 88template <class R, class RR> bool operator!=(const CachedResourceHandle<R>& h, const RR* res) 89{ 90 return h.get() != res; 91} 92template <class R, class RR> bool operator!=(const RR* res, const CachedResourceHandle<R>& h) 93{ 94 return h.get() != res; 95} 96 97} // namespace WebCore 98 99#endif // CachedResourceHandle 100