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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:
     41     PositionIterator()
     42         : m_anchorNode(nullptr)
     43         , m_nodeAfterPositionInAnchor(nullptr)
     44         , m_offsetInAnchor(0)
     45     {
     46     }
     47 
     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 
     59     Node* node() const { return m_anchorNode; }
     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