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: ref()34 void ref() 35 { 36 ASSERT(!m_deletionHasBegun); 37 ++m_refCount; 38 } 39 hasOneRef()40 bool hasOneRef() const 41 { 42 ASSERT(!m_deletionHasBegun); 43 return m_refCount == 1; 44 } 45 refCount()46 int refCount() const 47 { 48 return m_refCount; 49 } 50 51 protected: RefCountedBase()52 RefCountedBase() 53 : m_refCount(1) 54 #ifndef NDEBUG 55 , m_deletionHasBegun(false) 56 #endif 57 { 58 } 59 ~RefCountedBase()60 ~RefCountedBase() 61 { 62 } 63 64 // Returns whether the pointer should be freed or not. derefBase()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. addressOfCount()81 int* addressOfCount() 82 { 83 return &m_refCount; 84 } 85 86 #ifndef NDEBUG deletionHasBegun()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: deref()106 void deref() 107 { 108 if (derefBase()) 109 delete static_cast<T*>(this); 110 } 111 112 protected: ~RefCounted()113 ~RefCounted() 114 { 115 } 116 }; 117 118 template<class T> class RefCountedCustomAllocated : public RefCountedBase, public NoncopyableCustomAllocated { 119 public: deref()120 void deref() 121 { 122 if (derefBase()) 123 delete static_cast<T*>(this); 124 } 125 126 protected: ~RefCountedCustomAllocated()127 ~RefCountedCustomAllocated() 128 { 129 } 130 }; 131 132 } // namespace WTF 133 134 using WTF::RefCounted; 135 using WTF::RefCountedCustomAllocated; 136 137 #endif // RefCounted_h 138