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
29namespace WebCore {
30
31template <typename T> class DataRef {
32public:
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
65private:
66    RefPtr<T> m_data;
67};
68
69} // namespace WebCore
70
71#endif // DataRef_h
72