accessible/base/TextRange.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef mozilla_a11y_TextRange_h__
   8 #define mozilla_a11y_TextRange_h__
   9
  10 #include <utility>
  11
  12 #include "nsTArray.h"
  13
  14 class nsRange;
  15
  16 namespace mozilla {
  17 namespace dom {
  18 class Selection;
  19 }  // namespace dom
  20 namespace a11y {
  21
  22 class Accessible;
  23 class LocalAccessible;
  24
  25 /**
  26  * A text point (HyperText + offset), represents a boundary of text range.
  27  * In new code, This should only be used when you explicitly need to deal with
  28  * HyperText containers and offsets, including embedded objects; e.g. for
  29  * IAccessible2 and ATK. Otherwise, use TextLeafPoint instead.
  30  */
  31 struct TextPoint final {
  32   TextPoint(Accessible* aContainer, int32_t aOffset)
  33       : mContainer(aContainer), mOffset(aOffset) {}
  34   TextPoint(const TextPoint& aPoint)
  35       : mContainer(aPoint.mContainer), mOffset(aPoint.mOffset) {}
  36
  37   Accessible* mContainer;
  38   int32_t mOffset;
  39
  40   bool operator==(const TextPoint& aPoint) const {
  41     return mContainer == aPoint.mContainer && mOffset == aPoint.mOffset;
  42   }
  43   bool operator<(const TextPoint& aPoint) const;
  44 };
  45
  46 /**
  47  * Represents a HyperText range within the text control or document.
  48  * In new code, This should only be used when you explicitly need to deal with
  49  * HyperText containers and offsets, including embedded objects; e.g. for
  50  * IAccessible2 and ATK. Otherwise, use TextLeafRange instead.
  51  */
  52 class TextRange final {
  53  public:
  54   TextRange(Accessible* aRoot, Accessible* aStartContainer,
  55             int32_t aStartOffset, Accessible* aEndContainer,
  56             int32_t aEndOffset);
  57   TextRange() : mStartOffset{0}, mEndOffset{0} {}
  58   TextRange(TextRange&& aRange)
  59       : mRoot(std::move(aRange.mRoot)),
  60         mStartContainer(std::move(aRange.mStartContainer)),
  61         mEndContainer(std::move(aRange.mEndContainer)),
  62         mStartOffset(aRange.mStartOffset),
  63         mEndOffset(aRange.mEndOffset) {}
  64
  65   TextRange& operator=(TextRange&& aRange) {
  66     mRoot = std::move(aRange.mRoot);
  67     mStartContainer = std::move(aRange.mStartContainer);
  68     mEndContainer = std::move(aRange.mEndContainer);
  69     mStartOffset = aRange.mStartOffset;
  70     mEndOffset = aRange.mEndOffset;
  71     return *this;
  72   }
  73
  74   Accessible* Root() { return mRoot; }
  75   Accessible* StartContainer() const { return mStartContainer; }
  76   int32_t StartOffset() const { return mStartOffset; }
  77   Accessible* EndContainer() const { return mEndContainer; }
  78   int32_t EndOffset() const { return mEndOffset; }
  79
  80   bool operator==(const TextRange& aRange) const {
  81     return mStartContainer == aRange.mStartContainer &&
  82            mStartOffset == aRange.mStartOffset &&
  83            mEndContainer == aRange.mEndContainer &&
  84            mEndOffset == aRange.mEndOffset;
  85   }
  86
  87   TextPoint StartPoint() const {
  88     return TextPoint(mStartContainer, mStartOffset);
  89   }
  90   TextPoint EndPoint() const { return TextPoint(mEndContainer, mEndOffset); }
  91
  92   /**
  93    * Return a container containing both start and end points.
  94    */
  95   Accessible* Container() const;
  96
  97   /**
  98    * Return a list of embedded objects enclosed by the text range (includes
  99    * partially overlapped objects).
 100    */
 101   void EmbeddedChildren(nsTArray<Accessible*>* aChildren) const;
 102
 103   /**
 104    * Return text enclosed by the range.
 105    */
 106   void Text(nsAString& aText) const;
 107
 108   /**
 109    * Crops the range if it overlaps the given accessible element boundaries,
 110    * returns true if the range was cropped successfully.
 111    */
 112   bool Crop(Accessible* aContainer);
 113
 114   /**
 115    * Convert stored hypertext offsets into DOM offsets and assign it to DOM
 116    * range.
 117    *
 118    * Note that if start and/or end accessible offsets are in generated content
 119    * such as ::before or
 120    * ::after, the result range excludes the generated content.  See also
 121    * ClosestNotGeneratedDOMPoint() for more information.
 122    *
 123    * @param  aRange        [in, out] the range whose bounds to set
 124    * @param  aReversed     [out] whether the start/end offsets were reversed.
 125    * @return true   if conversion was successful
 126    */
 127   bool AssignDOMRange(nsRange* aRange, bool* aReversed = nullptr) const;
 128
 129   /**
 130    * Return true if this TextRange object represents an actual range of text.
 131    */
 132   bool IsValid() const { return mRoot; }
 133
 134   void SetStartPoint(Accessible* aContainer, int32_t aOffset) {
 135     mStartContainer = aContainer;
 136     mStartOffset = aOffset;
 137   }
 138   void SetEndPoint(Accessible* aContainer, int32_t aOffset) {
 139     mStartContainer = aContainer;
 140     mStartOffset = aOffset;
 141   }
 142
 143   static void TextRangesFromSelection(dom::Selection* aSelection,
 144                                       nsTArray<TextRange>* aRanges);
 145
 146  private:
 147   TextRange(const TextRange& aRange) = delete;
 148   TextRange& operator=(const TextRange& aRange) = delete;
 149
 150   friend class HyperTextAccessible;
 151   friend class xpcAccessibleTextRange;
 152
 153   void Set(Accessible* aRoot, Accessible* aStartContainer, int32_t aStartOffset,
 154            Accessible* aEndContainer, int32_t aEndOffset);
 155
 156   /**
 157    * Text() method helper.
 158    * @param  aText            [in,out] calculated text
 159    * @param  aCurrent         [in] currently traversed node
 160    * @param  aStartIntlOffset [in] start offset if current node is a text node
 161    * @return                   true if calculation is not finished yet
 162    */
 163   bool TextInternal(nsAString& aText, Accessible* aCurrent,
 164                     uint32_t aStartIntlOffset) const;
 165
 166   /**
 167    * A helper method returning a common parent for two given accessible
 168    * elements.
 169    */
 170   Accessible* CommonParent(Accessible* aAcc1, Accessible* aAcc2,
 171                            nsTArray<Accessible*>* aParents1, uint32_t* aPos1,
 172                            nsTArray<Accessible*>* aParents2,
 173                            uint32_t* aPos2) const;
 174
 175   Accessible* mRoot;
 176   Accessible* mStartContainer;
 177   Accessible* mEndContainer;
 178   int32_t mStartOffset;
 179   int32_t mEndOffset;
 180 };
 181
 182 }  // namespace a11y
 183 }  // namespace mozilla
 184
 185 #endif