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#pragma once
27
28#include "Node.h"
29
30namespace WebCore {
31
32// For use when you want to get the index for a node repeatedly and
33// only want to walk the child list to figure out the index once.
34class NodeWithIndex {
35public:
36 explicit NodeWithIndex(Node* node)
37 : m_node(node)
38 , m_haveIndex(false)
39 {
40 ASSERT(node);
41 }
42
43 Node* node() const { return m_node; }
44
45 int index() const
46 {
47 if (!m_haveIndex) {
48 m_index = m_node->computeNodeIndex();
49 m_haveIndex = true;
50 }
51 ASSERT(m_index == static_cast<int>(m_node->computeNodeIndex()));
52 return m_index;
53 }
54
55private:
56 Node* m_node;
57 mutable bool m_haveIndex;
58 mutable int m_index;
59};
60
61} // namespace WebCore
62