accessible/base/nsAccessiblePivot.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 _nsAccessiblePivot_H_
   8 #define _nsAccessiblePivot_H_
   9
  10 #include "nsIAccessiblePivot.h"
  11
  12 #include "Accessible-inl.h"
  13 #include "nsAutoPtr.h"
  14 #include "nsTObserverArray.h"
  15 #include "nsCycleCollectionParticipant.h"
  16 #include "mozilla/Attributes.h"
  17
  18 class RuleCache;
  19
  20 /**
  21  * Class represents an accessible pivot.
  22  */
  23 class nsAccessiblePivot MOZ_FINAL : public nsIAccessiblePivot
  24 {
  25 public:
  26   typedef mozilla::a11y::Accessible Accessible;
  27
  28   explicit nsAccessiblePivot(Accessible* aRoot);
  29
  30   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
  31   NS_DECL_CYCLE_COLLECTION_CLASS_AMBIGUOUS(nsAccessiblePivot, nsIAccessiblePivot)
  32
  33   NS_DECL_NSIACCESSIBLEPIVOT
  34
  35   /*
  36    * A simple getter for the pivot's position.
  37    */
  38   Accessible* Position() { return mPosition; }
  39
  40 private:
  41   ~nsAccessiblePivot();
  42   nsAccessiblePivot() = delete;
  43   nsAccessiblePivot(const nsAccessiblePivot&) = delete;
  44   void operator = (const nsAccessiblePivot&) = delete;
  45
  46   /*
  47    * Notify all observers on a pivot change. Return true if it has changed and
  48    * observers have been notified.
  49    */
  50   bool NotifyOfPivotChange(Accessible* aOldAccessible,
  51                            int32_t aOldStart, int32_t aOldEnd,
  52                            PivotMoveReason aReason,
  53                            bool aIsFromUserInput);
  54
  55   /*
  56    * Check to see that the given accessible is a descendant of given ancestor
  57    */
  58   bool IsDescendantOf(Accessible* aAccessible, Accessible* aAncestor);
  59
  60
  61   /*
  62    * Search in preorder for the first accessible to match the rule.
  63    */
  64   Accessible* SearchForward(Accessible* aAccessible,
  65                             nsIAccessibleTraversalRule* aRule,
  66                             bool aSearchCurrent,
  67                             nsresult* aResult);
  68
  69   /*
  70    * Reverse search in preorder for the first accessible to match the rule.
  71    */
  72   Accessible* SearchBackward(Accessible* aAccessible,
  73                              nsIAccessibleTraversalRule* aRule,
  74                              bool aSearchCurrent,
  75                              nsresult* aResult);
  76
  77   /*
  78    * Search in preorder for the first text accessible.
  79    */
  80   mozilla::a11y::HyperTextAccessible* SearchForText(Accessible* aAccessible,
  81                                                     bool aBackward);
  82
  83   /*
  84    * Get the effective root for this pivot, either the true root or modal root.
  85    */
  86   Accessible* GetActiveRoot() const
  87   {
  88     if (mModalRoot) {
  89       NS_ENSURE_FALSE(mModalRoot->IsDefunct(), mRoot);
  90       return mModalRoot;
  91     }
  92
  93     return mRoot;
  94   }
  95
  96   /*
  97    * Update the pivot, and notify observers. Return true if it moved.
  98    */
  99   bool MovePivotInternal(Accessible* aPosition, PivotMoveReason aReason,
 100                          bool aIsFromUserInput);
 101
 102   /*
 103    * Get initial node we should start a search from with a given rule.
 104    *
 105    * When we do a move operation from one position to another,
 106    * the initial position can be inside of a subtree that is ignored by
 107    * the given rule. We need to step out of the ignored subtree and start
 108    * the search from there.
 109    *
 110    */
 111   Accessible* AdjustStartPosition(Accessible* aAccessible, RuleCache& aCache,
 112                                   uint16_t* aFilterResult, nsresult* aResult);
 113
 114   /*
 115    * The root accessible.
 116    */
 117   nsRefPtr<Accessible> mRoot;
 118
 119   /*
 120    * The temporary modal root accessible.
 121    */
 122   nsRefPtr<Accessible> mModalRoot;
 123
 124   /*
 125    * The current pivot position.
 126    */
 127   nsRefPtr<Accessible> mPosition;
 128
 129   /*
 130    * The text start offset ofthe pivot.
 131    */
 132   int32_t mStartOffset;
 133
 134   /*
 135    * The text end offset ofthe pivot.
 136    */
 137   int32_t mEndOffset;
 138
 139   /*
 140    * The list of pivot-changed observers.
 141    */
 142   nsTObserverArray<nsCOMPtr<nsIAccessiblePivotObserver> > mObservers;
 143 };
 144
 145 #endif