1/*
2 * Copyright (C) 2008 Apple Inc. All Rights Reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#ifndef NodeWithIndex_h
27#define NodeWithIndex_h
28
29#include "core/dom/Node.h"
30#include "platform/heap/Handle.h"
31
32namespace blink {
33
34// For use when you want to get the index for a node repeatedly and
35// only want to walk the child list to figure out the index once.
36class NodeWithIndex {
37    STACK_ALLOCATED();
38public:
39    explicit NodeWithIndex(Node& node)
40        : m_node(node)
41        , m_index(-1)
42    {
43    }
44
45    Node& node() const { return *m_node; }
46
47    int index() const
48    {
49        if (!hasIndex())
50            m_index = node().nodeIndex();
51        ASSERT(hasIndex());
52        ASSERT(m_index == static_cast<int>(node().nodeIndex()));
53        return m_index;
54    }
55
56private:
57    bool hasIndex() const { return m_index >= 0; }
58
59    RawPtrWillBeMember<Node> m_node;
60    mutable int m_index;
61};
62
63}
64
65#endif
66