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 | |
30 | namespace WebCore { |
31 | |
32 | class CachedResource; |
33 | |
34 | class WEBCORE_EXPORT CachedResourceHandleBase { |
35 | public: |
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 | |
46 | protected: |
47 | CachedResourceHandleBase(); |
48 | CachedResourceHandleBase(CachedResource*); |
49 | CachedResourceHandleBase(const CachedResourceHandleBase&); |
50 | |
51 | void setResource(CachedResource*); |
52 | |
53 | private: |
54 | CachedResourceHandleBase& operator=(const CachedResourceHandleBase&) { return *this; } |
55 | |
56 | friend class CachedResource; |
57 | |
58 | CachedResource* m_resource; |
59 | }; |
60 | |
61 | template <class R> class CachedResourceHandle : public CachedResourceHandleBase { |
62 | public: |
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 | |
80 | template <class R, class RR> bool operator==(const CachedResourceHandle<R>& h, const RR* res) |
81 | { |
82 | return h.get() == res; |
83 | } |
84 | template <class R, class RR> bool operator==(const RR* res, const CachedResourceHandle<R>& h) |
85 | { |
86 | return h.get() == res; |
87 | } |
88 | template <class R, class RR> bool operator!=(const CachedResourceHandle<R>& h, const RR* res) |
89 | { |
90 | return h.get() != res; |
91 | } |
92 | template <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 | |