WebCore/DataRef.h

   1 /*
   2  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
   3  *           (C) 2000 Antti Koivisto (koivisto@kde.org)
   4  *           (C) 2000 Dirk Mueller (mueller@kde.org)
   5  * Copyright (C) 2003, 2005, 2008 Apple Inc. All rights reserved.
   6  *
   7  * This library is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Library General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2 of the License, or (at your option) any later version.
  11  *
  12  * This library is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Library General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Library General Public License
  18  * along with this library; see the file COPYING.LIB.  If not, write to
  19  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  20  * Boston, MA 02110-1301, USA.
  21  *
  22  */
  23
  24 #ifndef DataRef_h
  25 #define DataRef_h
  26
  27 #include <wtf/RefPtr.h>
  28
  29 namespace WebCore {
  30
  31 template <typename T> class DataRef {
  32 public:
  33     const T* get() const { return m_data.get(); }
  34
  35     const T& operator*() const { return *get(); }
  36     const T* operator->() const { return get(); }
  37
  38     T* access()
  39     {
  40         if (!m_data->hasOneRef())
  41             m_data = m_data->copy();
  42         return m_data.get();
  43     }
  44
  45     void init()
  46     {
  47         ASSERT(!m_data);
  48         m_data = T::create();
  49     }
  50
  51     bool operator==(const DataRef<T>& o) const
  52     {
  53         ASSERT(m_data);
  54         ASSERT(o.m_data);
  55         return m_data == o.m_data || *m_data == *o.m_data;
  56     }
  57
  58     bool operator!=(const DataRef<T>& o) const
  59     {
  60         ASSERT(m_data);
  61         ASSERT(o.m_data);
  62         return m_data != o.m_data && *m_data != *o.m_data;
  63     }
  64
  65 private:
  66     RefPtr<T> m_data;
  67 };
  68
  69 } // namespace WebCore
  70
  71 #endif // DataRef_h