1 | /* |
2 | * Copyright (C) 2006, 2007, 2008 Apple Inc. All rights reserved. |
3 | * |
4 | * This library is free software; you can redistribute it and/or |
5 | * modify it under the terms of the GNU Library General Public |
6 | * License as published by the Free Software Foundation; either |
7 | * version 2 of the License, or (at your option) any later version. |
8 | * |
9 | * This library is distributed in the hope that it will be useful, |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
12 | * Library General Public License for more details. |
13 | * |
14 | * You should have received a copy of the GNU Library General Public License |
15 | * along with this library; see the file COPYING.LIB. If not, write to |
16 | * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, |
17 | * Boston, MA 02110-1301, USA. |
18 | * |
19 | */ |
20 | |
21 | #ifndef RefCounted_h |
22 | #define RefCounted_h |
23 | |
24 | #include <wtf/Assertions.h> |
25 | #include <wtf/Noncopyable.h> |
26 | |
27 | namespace WTF { |
28 | |
29 | // This base class holds the non-template methods and attributes. |
30 | // The RefCounted class inherits from it reducing the template bloat |
31 | // generated by the compiler (technique called template hoisting). |
32 | class RefCountedBase { |
33 | public: |
34 | void ref() |
35 | { |
36 | ASSERT(!m_deletionHasBegun); |
37 | ++m_refCount; |
38 | } |
39 | |
40 | bool hasOneRef() const |
41 | { |
42 | ASSERT(!m_deletionHasBegun); |
43 | return m_refCount == 1; |
44 | } |
45 | |
46 | int refCount() const |
47 | { |
48 | return m_refCount; |
49 | } |
50 | |
51 | protected: |
52 | RefCountedBase() |
53 | : m_refCount(1) |
54 | #ifndef NDEBUG |
55 | , m_deletionHasBegun(false) |
56 | #endif |
57 | { |
58 | } |
59 | |
60 | ~RefCountedBase() |
61 | { |
62 | } |
63 | |
64 | // Returns whether the pointer should be freed or not. |
65 | bool derefBase() |
66 | { |
67 | ASSERT(!m_deletionHasBegun); |
68 | ASSERT(m_refCount > 0); |
69 | if (m_refCount == 1) { |
70 | #ifndef NDEBUG |
71 | m_deletionHasBegun = true; |
72 | #endif |
73 | return true; |
74 | } |
75 | |
76 | --m_refCount; |
77 | return false; |
78 | } |
79 | |
80 | // Helper for generating JIT code. Please do not use for non-JIT purposes. |
81 | int* addressOfCount() |
82 | { |
83 | return &m_refCount; |
84 | } |
85 | |
86 | #ifndef NDEBUG |
87 | bool deletionHasBegun() const |
88 | { |
89 | return m_deletionHasBegun; |
90 | } |
91 | #endif |
92 | |
93 | private: |
94 | template<class T> |
95 | friend class CrossThreadRefCounted; |
96 | |
97 | int m_refCount; |
98 | #ifndef NDEBUG |
99 | bool m_deletionHasBegun; |
100 | #endif |
101 | }; |
102 | |
103 | |
104 | template<class T> class RefCounted : public RefCountedBase, public Noncopyable { |
105 | public: |
106 | void deref() |
107 | { |
108 | if (derefBase()) |
109 | delete static_cast<T*>(this); |
110 | } |
111 | |
112 | protected: |
113 | ~RefCounted() |
114 | { |
115 | } |
116 | }; |
117 | |
118 | template<class T> class RefCountedCustomAllocated : public RefCountedBase, public NoncopyableCustomAllocated { |
119 | public: |
120 | void deref() |
121 | { |
122 | if (derefBase()) |
123 | delete static_cast<T*>(this); |
124 | } |
125 | |
126 | protected: |
127 | ~RefCountedCustomAllocated() |
128 | { |
129 | } |
130 | }; |
131 | |
132 | } // namespace WTF |
133 | |
134 | using WTF::RefCounted; |
135 | using WTF::RefCountedCustomAllocated; |
136 | |
137 | #endif // RefCounted_h |
138 | |