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1 /*
2  * Copyright (C) 2007, 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 PositionIterator_h
27 #define PositionIterator_h
28 
29 #include "core/dom/Node.h"
30 #include "core/dom/NodeTraversal.h"
31 #include "core/dom/Position.h"
32 
33 namespace blink {
34 
35 // A Position iterator with constant-time
36 // increment, decrement, and several predicates on the Position it is at.
37 // Conversion to/from Position is O(n) in the offset.
38 class PositionIterator {
39     STACK_ALLOCATED();
40 public:
PositionIterator()41     PositionIterator()
42         : m_anchorNode(nullptr)
43         , m_nodeAfterPositionInAnchor(nullptr)
44         , m_offsetInAnchor(0)
45     {
46     }
47 
PositionIterator(const Position & pos)48     PositionIterator(const Position& pos)
49         : m_anchorNode(pos.anchorNode())
50         , m_nodeAfterPositionInAnchor(NodeTraversal::childAt(*m_anchorNode, pos.deprecatedEditingOffset()))
51         , m_offsetInAnchor(m_nodeAfterPositionInAnchor ? 0 : pos.deprecatedEditingOffset())
52     {
53     }
54     operator Position() const;
55 
56     void increment();
57     void decrement();
58 
node()59     Node* node() const { return m_anchorNode; }
offsetInLeafNode()60     int offsetInLeafNode() const { return m_offsetInAnchor; }
61 
62     bool atStart() const;
63     bool atEnd() const;
64     bool atStartOfNode() const;
65     bool atEndOfNode() const;
66     bool isCandidate() const;
67 
68 private:
69     RawPtrWillBeMember<Node> m_anchorNode;
70     RawPtrWillBeMember<Node> m_nodeAfterPositionInAnchor; // If this is non-null, m_nodeAfterPositionInAnchor->parentNode() == m_anchorNode;
71     int m_offsetInAnchor;
72 };
73 
74 } // namespace blink
75 
76 #endif // PositionIterator_h
77