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