wtf/RefCounted.h

   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 template<class T> class RefCounted : Noncopyable {
  30 public:
  31     RefCounted(int initialRefCount = 0)
  32         : m_refCount(initialRefCount)
  33 #ifndef NDEBUG
  34         , m_deletionHasBegun(false)
  35 #endif
  36     {
  37     }
  38
  39     void ref()
  40     {
  41         ASSERT(!m_deletionHasBegun);
  42         ++m_refCount;
  43     }
  44
  45     void deref()
  46     {
  47         ASSERT(!m_deletionHasBegun);
  48         ASSERT(m_refCount > 0);
  49         if (m_refCount == 1) {
  50 #ifndef NDEBUG
  51             m_deletionHasBegun = true;
  52 #endif
  53             delete static_cast<T*>(this);
  54         } else
  55             --m_refCount;
  56     }
  57
  58     bool hasOneRef()
  59     {
  60         ASSERT(!m_deletionHasBegun);
  61         return m_refCount == 1;
  62     }
  63
  64     int refCount() const
  65     {
  66         return m_refCount;
  67     }
  68
  69 private:
  70     int m_refCount;
  71 #ifndef NDEBUG
  72     bool m_deletionHasBegun;
  73 #endif
  74 };
  75
  76 } // namespace WTF
  77
  78 using WTF::RefCounted;
  79
  80 #endif // RefCounted_h