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#pragma once
27
28#include <wtf/Forward.h>
29
30namespace WebCore {
31
32class CachedResource;
33
34class WEBCORE_EXPORT CachedResourceHandleBase {
35public:
36 ~CachedResourceHandleBase();
37
38 CachedResource* get() const { return m_resource; }
39
40 bool operator!() const { return !m_resource; }
41
42 // This conversion operator allows implicit conversion to bool but not to other integer types.
43 typedef CachedResource* CachedResourceHandleBase::*UnspecifiedBoolType;
44 operator UnspecifiedBoolType() const { return m_resource ? &CachedResourceHandleBase::m_resource : 0; }
45
46protected:
47 CachedResourceHandleBase();
48 CachedResourceHandleBase(CachedResource*);
49 CachedResourceHandleBase(const CachedResourceHandleBase&);
50
51 void setResource(CachedResource*);
52
53private:
54 CachedResourceHandleBase& operator=(const CachedResourceHandleBase&) { return *this; }
55
56 friend class CachedResource;
57
58 CachedResource* m_resource;
59};
60
61template <class R> class CachedResourceHandle : public CachedResourceHandleBase {
62public:
63 CachedResourceHandle() { }
64 CachedResourceHandle(R* res) : CachedResourceHandleBase(res) { }
65 CachedResourceHandle(const CachedResourceHandle<R>& o) : CachedResourceHandleBase(o) { }
66 template<typename U> CachedResourceHandle(const CachedResourceHandle<U>& o) : CachedResourceHandleBase(o.get()) { }
67
68 R* get() const { return reinterpret_cast<R*>(CachedResourceHandleBase::get()); }
69 R* operator->() const { return get(); }
70 R& operator*() const { ASSERT(get()); 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