WebCore/dom/Position.h

   1 /*
   2  * Copyright (C) 2004, 2006, 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 Position_h
  27 #define Position_h
  28
  29 #include "TextAffinity.h"
  30 #include "TextDirection.h"
  31 #include <wtf/PassRefPtr.h>
  32 #include <wtf/RefPtr.h>
  33
  34 namespace WebCore {
  35
  36 class CSSComputedStyleDeclaration;
  37 class Element;
  38 class InlineBox;
  39 class Node;
  40 class Range;
  41 class RenderObject;
  42
  43 enum EUsingComposedCharacters { NotUsingComposedCharacters = false, UsingComposedCharacters = true };
  44
  45 // FIXME: Reduce the number of operations we have on a Position.
  46 // This should be more like a humble struct, without so many different
  47 // member functions. We should find better homes for these functions.
  48
  49 class Position {
  50 public:
  51     RefPtr<Node> container;
  52     int posOffset; // to be renamed to offset when we get rid of offset()
  53
  54     Position() : posOffset(0) { }
  55     Position(PassRefPtr<Node> c, int o) : container(c), posOffset(o) { }
  56
  57     void clear() { container.clear(); posOffset = 0; }
  58
  59     Node* node() const { return container.get(); }
  60     int offset() const { return posOffset; }
  61     Element* documentElement() const;
  62
  63     bool isNull() const { return !container; }
  64     bool isNotNull() const { return container; }
  65
  66     Element* element() const;
  67     PassRefPtr<CSSComputedStyleDeclaration> computedStyle() const;
  68
  69     // Move up or down the DOM by one position.
  70     // Offsets are computed using render text for nodes that have renderers - but note that even when
  71     // using composed characters, the result may be inside a single user-visible character if a ligature is formed.
  72     Position previous(EUsingComposedCharacters usingComposedCharacters=NotUsingComposedCharacters) const;
  73     Position next(EUsingComposedCharacters usingComposedCharacters=NotUsingComposedCharacters) const;
  74     static int uncheckedPreviousOffset(const Node*, int current);
  75     static int uncheckedNextOffset(const Node*, int current);
  76
  77     bool atStart() const;
  78     bool atEnd() const;
  79
  80     // FIXME: Make these non-member functions and put them somewhere in the editing directory.
  81     // These aren't really basic "position" operations. More high level editing helper functions.
  82     Position leadingWhitespacePosition(EAffinity, bool considerNonCollapsibleWhitespace = false) const;
  83     Position trailingWhitespacePosition(EAffinity, bool considerNonCollapsibleWhitespace = false) const;
  84
  85     // These return useful visually equivalent positions.
  86     Position upstream() const;
  87     Position downstream() const;
  88
  89     bool isCandidate() const;
  90     bool inRenderedText() const;
  91     bool isRenderedCharacter() const;
  92     bool rendersInDifferentPosition(const Position&) const;
  93
  94     void getInlineBoxAndOffset(EAffinity, InlineBox*&, int& caretOffset) const;
  95     void getInlineBoxAndOffset(EAffinity, TextDirection primaryDirection, InlineBox*&, int& caretOffset) const;
  96
  97     static bool hasRenderedNonAnonymousDescendantsWithHeight(RenderObject*);
  98     static bool nodeIsUserSelectNone(Node*);
  99
 100     void debugPosition(const char* msg = "") const;
 101
 102 #ifndef NDEBUG
 103     void formatForDebugger(char* buffer, unsigned length) const;
 104     void showTreeForThis() const;
 105 #endif
 106
 107 private:
 108     int renderedOffset() const;
 109
 110     Position previousCharacterPosition(EAffinity) const;
 111     Position nextCharacterPosition(EAffinity) const;
 112 };
 113
 114 inline bool operator==(const Position& a, const Position& b)
 115 {
 116     return a.container == b.container && a.posOffset == b.posOffset;
 117 }
 118
 119 inline bool operator!=(const Position& a, const Position& b)
 120 {
 121     return !(a == b);
 122 }
 123
 124 Position startPosition(const Range*);
 125 Position endPosition(const Range*);
 126
 127 } // namespace WebCore
 128
 129 #ifndef NDEBUG
 130 // Outside the WebCore namespace for ease of invocation from gdb.
 131 void showTree(const WebCore::Position&);
 132 void showTree(const WebCore::Position*);
 133 #endif
 134
 135 #endif // Position_h