src/third_party/WebKit/Source/core/dom/TreeShared.h

   1 /*
   2  * Copyright (C) 2006, 2007, 2009, 2010, 2012 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 "public/platform/WebPrivatePtr.h"
  25 #include "wtf/Assertions.h"
  26 #include "wtf/MainThread.h"
  27 #include "wtf/Noncopyable.h"
  28
  29 namespace blink {
  30
  31 #if ENABLE(SECURITY_ASSERT)
  32 template<typename NodeType> class TreeShared;
  33 template<typename NodeType> void adopted(TreeShared<NodeType>*);
  34 #endif
  35
  36 template<typename NodeType> class TreeShared : public NoBaseWillBeGarbageCollectedFinalized<NodeType> {
  37     WTF_MAKE_NONCOPYABLE(TreeShared);
  38 protected:
  39     TreeShared()
  40         : m_refCount(1)
  41 #if ENABLE(SECURITY_ASSERT)
  42         , m_deletionHasBegun(false)
  43 #if ENABLE(ASSERT)
  44         , m_inRemovedLastRefFunction(false)
  45         , m_adoptionIsRequired(true)
  46 #endif
  47 #endif
  48     {
  49         ASSERT(isMainThread());
  50     }
  51
  52     ~TreeShared()
  53     {
  54         ASSERT(isMainThread());
  55         ASSERT(!m_refCount);
  56         ASSERT_WITH_SECURITY_IMPLICATION(m_deletionHasBegun);
  57         ASSERT(!m_adoptionIsRequired);
  58     }
  59
  60 public:
  61     void ref()
  62     {
  63         ASSERT(isMainThread());
  64         ASSERT_WITH_SECURITY_IMPLICATION(!m_deletionHasBegun);
  65         ASSERT(!m_inRemovedLastRefFunction);
  66         ASSERT(!m_adoptionIsRequired);
  67         ++m_refCount;
  68     }
  69
  70     void deref()
  71     {
  72         ASSERT(isMainThread());
  73         ASSERT(m_refCount > 0);
  74         ASSERT_WITH_SECURITY_IMPLICATION(!m_deletionHasBegun);
  75         ASSERT(!m_inRemovedLastRefFunction);
  76         ASSERT(!m_adoptionIsRequired);
  77         NodeType* thisNode = static_cast<NodeType*>(this);
  78         if (!--m_refCount && !thisNode->hasTreeSharedParent()) {
  79 #if ENABLE(ASSERT)
  80             m_inRemovedLastRefFunction = true;
  81 #endif
  82             thisNode->removedLastRef();
  83         }
  84     }
  85
  86     int refCount() const { return m_refCount; }
  87
  88 private:
  89     int m_refCount;
  90
  91 #if ENABLE(SECURITY_ASSERT)
  92 public:
  93     bool m_deletionHasBegun;
  94 #if ENABLE(ASSERT)
  95     bool m_inRemovedLastRefFunction;
  96
  97 private:
  98     friend void adopted<>(TreeShared<NodeType>*);
  99     bool m_adoptionIsRequired;
 100 #endif
 101 #endif
 102 };
 103
 104 #if ENABLE(SECURITY_ASSERT)
 105 template<typename NodeType> void adopted(TreeShared<NodeType>* object)
 106 {
 107     if (!object)
 108         return;
 109
 110     ASSERT_WITH_SECURITY_IMPLICATION(!object->m_deletionHasBegun);
 111 #if ENABLE(ASSERT)
 112     ASSERT(!object->m_inRemovedLastRefFunction);
 113     object->m_adoptionIsRequired = false;
 114 #endif
 115 }
 116 #endif
 117
 118 }
 119
 120 #endif // TreeShared.h