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      1 /*
      2  * Copyright (C) 2004, 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 COMPUTER, 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 COMPUTER, 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 VisiblePosition_h
     27 #define VisiblePosition_h
     28 
     29 #include "core/dom/Position.h"
     30 #include "core/editing/EditingBoundary.h"
     31 #include "core/platform/text/TextDirection.h"
     32 
     33 namespace WebCore {
     34 
     35 // VisiblePosition default affinity is downstream because
     36 // the callers do not really care (they just want the
     37 // deep position without regard to line position), and this
     38 // is cheaper than UPSTREAM
     39 #define VP_DEFAULT_AFFINITY DOWNSTREAM
     40 
     41 // Callers who do not know where on the line the position is,
     42 // but would like UPSTREAM if at a line break or DOWNSTREAM
     43 // otherwise, need a clear way to specify that.  The
     44 // constructors auto-correct UPSTREAM to DOWNSTREAM if the
     45 // position is not at a line break.
     46 #define VP_UPSTREAM_IF_POSSIBLE UPSTREAM
     47 
     48 class InlineBox;
     49 class Node;
     50 
     51 class VisiblePosition {
     52 public:
     53     // NOTE: UPSTREAM affinity will be used only if pos is at end of a wrapped line,
     54     // otherwise it will be converted to DOWNSTREAM
     55     VisiblePosition() : m_affinity(VP_DEFAULT_AFFINITY) { }
     56     VisiblePosition(const Position&, EAffinity = VP_DEFAULT_AFFINITY);
     57     explicit VisiblePosition(const PositionWithAffinity&);
     58 
     59     void clear() { m_deepPosition.clear(); }
     60 
     61     bool isNull() const { return m_deepPosition.isNull(); }
     62     bool isNotNull() const { return m_deepPosition.isNotNull(); }
     63     bool isOrphan() const { return m_deepPosition.isOrphan(); }
     64 
     65     Position deepEquivalent() const { return m_deepPosition; }
     66     EAffinity affinity() const { ASSERT(m_affinity == UPSTREAM || m_affinity == DOWNSTREAM); return m_affinity; }
     67     void setAffinity(EAffinity affinity) { m_affinity = affinity; }
     68 
     69     // FIXME: Change the following functions' parameter from a boolean to StayInEditableContent.
     70 
     71     // next() and previous() will increment/decrement by a character cluster.
     72     VisiblePosition next(EditingBoundaryCrossingRule = CanCrossEditingBoundary) const;
     73     VisiblePosition previous(EditingBoundaryCrossingRule = CanCrossEditingBoundary) const;
     74     VisiblePosition honorEditingBoundaryAtOrBefore(const VisiblePosition&) const;
     75     VisiblePosition honorEditingBoundaryAtOrAfter(const VisiblePosition&) const;
     76 
     77     VisiblePosition left(bool stayInEditableContent = false) const;
     78     VisiblePosition right(bool stayInEditableContent = false) const;
     79 
     80     UChar32 characterAfter() const;
     81     UChar32 characterBefore() const { return previous().characterAfter(); }
     82 
     83     // FIXME: This does not handle [table, 0] correctly.
     84     Element* rootEditableElement() const { return m_deepPosition.isNotNull() ? m_deepPosition.deprecatedNode()->rootEditableElement() : 0; }
     85 
     86     void getInlineBoxAndOffset(InlineBox*& inlineBox, int& caretOffset) const
     87     {
     88         m_deepPosition.getInlineBoxAndOffset(m_affinity, inlineBox, caretOffset);
     89     }
     90 
     91     void getInlineBoxAndOffset(TextDirection primaryDirection, InlineBox*& inlineBox, int& caretOffset) const
     92     {
     93         m_deepPosition.getInlineBoxAndOffset(m_affinity, primaryDirection, inlineBox, caretOffset);
     94     }
     95 
     96     // Rect is local to the returned renderer
     97     LayoutRect localCaretRect(RenderObject*&) const;
     98     // Bounds of (possibly transformed) caret in absolute coords
     99     IntRect absoluteCaretBounds() const;
    100     // Abs x/y position of the caret ignoring transforms.
    101     // FIXME: navigation with transforms should be smarter.
    102     int lineDirectionPointForBlockDirectionNavigation() const;
    103 
    104 #ifndef NDEBUG
    105     void debugPosition(const char* msg = "") const;
    106     void formatForDebugger(char* buffer, unsigned length) const;
    107     void showTreeForThis() const;
    108 #endif
    109 
    110 private:
    111     void init(const Position&, EAffinity);
    112     Position canonicalPosition(const Position&);
    113 
    114     Position leftVisuallyDistinctCandidate() const;
    115     Position rightVisuallyDistinctCandidate() const;
    116 
    117     Position m_deepPosition;
    118     EAffinity m_affinity;
    119 };
    120 
    121 // FIXME: This shouldn't ignore affinity.
    122 inline bool operator==(const VisiblePosition& a, const VisiblePosition& b)
    123 {
    124     return a.deepEquivalent() == b.deepEquivalent();
    125 }
    126 
    127 inline bool operator!=(const VisiblePosition& a, const VisiblePosition& b)
    128 {
    129     return !(a == b);
    130 }
    131 
    132 PassRefPtr<Range> makeRange(const VisiblePosition&, const VisiblePosition&);
    133 bool setStart(Range*, const VisiblePosition&);
    134 bool setEnd(Range*, const VisiblePosition&);
    135 VisiblePosition startVisiblePosition(const Range*, EAffinity);
    136 VisiblePosition endVisiblePosition(const Range*, EAffinity);
    137 
    138 Element* enclosingBlockFlowElement(const VisiblePosition&);
    139 
    140 bool isFirstVisiblePositionInNode(const VisiblePosition&, const Node*);
    141 bool isLastVisiblePositionInNode(const VisiblePosition&, const Node*);
    142 
    143 } // namespace WebCore
    144 
    145 #ifndef NDEBUG
    146 // Outside the WebCore namespace for ease of invocation from gdb.
    147 void showTree(const WebCore::VisiblePosition*);
    148 void showTree(const WebCore::VisiblePosition&);
    149 #endif
    150 
    151 #endif // VisiblePosition_h
    152