1 /* 2 * Copyright (C) 2006, 2007 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 TreeShared_h 22 #define TreeShared_h 23 24 #include <wtf/Assertions.h> 25 #include <wtf/Noncopyable.h> 26 27 namespace WebCore { 28 29 template<class T> class TreeShared : public Noncopyable { 30 public: TreeShared()31 TreeShared() 32 : m_refCount(0) 33 , m_parent(0) 34 { 35 #ifndef NDEBUG 36 m_deletionHasBegun = false; 37 m_inRemovedLastRefFunction = false; 38 #endif 39 } TreeShared(T * parent)40 TreeShared(T* parent) 41 : m_refCount(0) 42 , m_parent(0) 43 { 44 #ifndef NDEBUG 45 m_deletionHasBegun = false; 46 m_inRemovedLastRefFunction = false; 47 #endif 48 } ~TreeShared()49 virtual ~TreeShared() 50 { 51 ASSERT(m_deletionHasBegun); 52 } 53 ref()54 void ref() 55 { 56 ASSERT(!m_deletionHasBegun); 57 ASSERT(!m_inRemovedLastRefFunction); 58 ++m_refCount; 59 } 60 deref()61 void deref() 62 { 63 ASSERT(!m_deletionHasBegun); 64 ASSERT(!m_inRemovedLastRefFunction); 65 if (--m_refCount <= 0 && !m_parent) { 66 #ifndef NDEBUG 67 m_inRemovedLastRefFunction = true; 68 #endif 69 removedLastRef(); 70 } 71 } 72 hasOneRef()73 bool hasOneRef() const 74 { 75 ASSERT(!m_deletionHasBegun); 76 ASSERT(!m_inRemovedLastRefFunction); 77 return m_refCount == 1; 78 } 79 refCount()80 int refCount() const 81 { 82 return m_refCount; 83 } 84 setParent(T * parent)85 void setParent(T* parent) { m_parent = parent; } parent()86 T* parent() const { return m_parent; } 87 88 #ifndef NDEBUG 89 bool m_deletionHasBegun; 90 bool m_inRemovedLastRefFunction; 91 #endif 92 93 private: removedLastRef()94 virtual void removedLastRef() 95 { 96 #ifndef NDEBUG 97 m_deletionHasBegun = true; 98 #endif 99 delete this; 100 } 101 102 int m_refCount; 103 T* m_parent; 104 }; 105 106 } 107 108 #endif // TreeShared.h 109