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/PassRef.h>
28#include <wtf/Ref.h>
29
30namespace WebCore {
31
32template <typename T> class DataRef {
33public:
34    DataRef(PassRef<T> data) : m_data(WTF::move(data)) { }
35    DataRef(const DataRef& other) : m_data(const_cast<T&>(other.m_data.get())) { }
36    DataRef& operator=(const DataRef& other) { m_data = const_cast<T&>(other.m_data.get()); return *this; }
37
38    const T* get() const { return &m_data.get(); }
39
40    const T& operator*() const { return *get(); }
41    const T* operator->() const { return get(); }
42
43    T* access()
44    {
45        if (!m_data->hasOneRef())
46            m_data = m_data->copy();
47        return &m_data.get();
48    }
49
50    bool operator==(const DataRef<T>& o) const
51    {
52        return &m_data.get() == &o.m_data.get() || m_data.get() == o.m_data.get();
53    }
54
55    bool operator!=(const DataRef<T>& o) const
56    {
57        return &m_data.get() != &o.m_data.get() && m_data.get() != o.m_data.get();
58    }
59
60private:
61    Ref<T> m_data;
62};
63
64} // namespace WebCore
65
66#endif // DataRef_h
67