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