accessible/base/SelectionManager.h

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #ifndef mozilla_a11y_SelectionManager_h__
   7 #define mozilla_a11y_SelectionManager_h__
   8
   9 #include "nsISelectionListener.h"
  10 #include "mozilla/WeakPtr.h"
  11
  12 class nsRange;
  13
  14 namespace mozilla {
  15
  16 class PresShell;
  17
  18 namespace dom {
  19 class Element;
  20 class Selection;
  21 }  // namespace dom
  22
  23 namespace a11y {
  24
  25 class AccEvent;
  26 class HyperTextAccessible;
  27
  28 /**
  29  * This special accessibility class is for the caret and selection management.
  30  * There is only 1 visible caret per top level window. However, there may be
  31  * several visible selections.
  32  *
  33  * The important selections are the one owned by each document, and the one in
  34  * the currently focused control.
  35  *
  36  * On Windows this class is used to move an invisible system caret that
  37  * shadows the Mozilla caret. Windows will also automatically map this to
  38  * the MSAA caret accessible object (via OBJID_CARET) (as opposed to the root
  39  * accessible tree for a window which is retrieved with OBJID_CLIENT).
  40  *
  41  * For ATK and IAccessible2, this class is used to fire caret move and
  42  * selection change events.
  43  */
  44
  45 struct SelData;
  46
  47 class SelectionManager : public nsISelectionListener {
  48  public:
  49   // nsISupports
  50   // implemented by derived nsAccessibilityService
  51
  52   // nsISelectionListener
  53   NS_DECL_NSISELECTIONLISTENER
  54
  55   // SelectionManager
  56   void Shutdown() { ClearControlSelectionListener(); }
  57
  58   /**
  59    * Listen to selection events on the focused control.
  60    *
  61    * Note: only one control's selection events are listened to at a time. This
  62    * will remove the previous control's selection listener.
  63    */
  64   void SetControlSelectionListener(dom::Element* aFocusedElm);
  65
  66   /**
  67    * Stop listening to selection events on the control.
  68    */
  69   void ClearControlSelectionListener();
  70
  71   /**
  72    * Listen to selection events on the document.
  73    */
  74   void AddDocSelectionListener(PresShell* aPresShell);
  75
  76   /**
  77    * Stop listening to selection events for a given document
  78    */
  79   void RemoveDocSelectionListener(PresShell* aPresShell);
  80
  81   /**
  82    * Process delayed event, results in caret move and text selection change
  83    * events.
  84    */
  85   void ProcessTextSelChangeEvent(AccEvent* aEvent);
  86
  87   /**
  88    * Gets the current caret offset/hypertext accessible pair. If there is no
  89    * current pair, then returns -1 for the offset and a nullptr for the
  90    * accessible.
  91    */
  92   inline HyperTextAccessible* AccessibleWithCaret(int32_t* aCaret) {
  93     if (aCaret) *aCaret = mCaretOffset;
  94
  95     return mAccWithCaret;
  96   }
  97
  98   /**
  99    * Update caret offset when it doesn't go through a caret move event.
 100    */
 101   inline void UpdateCaretOffset(HyperTextAccessible* aItem, int32_t aOffset) {
 102     mAccWithCaret = aItem;
 103     mCaretOffset = aOffset;
 104   }
 105
 106   inline void ResetCaretOffset() {
 107     mCaretOffset = -1;
 108     mAccWithCaret = nullptr;
 109   }
 110
 111   /**
 112    * Called by mozInlineSpellChecker when a spell check range is added/removed.
 113    * nsISelectionListener isn't sufficient for spelling errors, since it only
 114    * tells us that there was a change, not which range changed. We don't want
 115    * to unnecessarily push a cache update for all Accessibles in the entire
 116    * selection.
 117    */
 118   void SpellCheckRangeChanged(const nsRange& aRange);
 119
 120   ~SelectionManager();
 121
 122  protected:
 123   SelectionManager();
 124
 125   /**
 126    * Process DOM selection change. Fire selection and caret move events.
 127    */
 128   void ProcessSelectionChanged(SelData* aSelData);
 129
 130  private:
 131   // Currently focused control.
 132   int32_t mCaretOffset;
 133   HyperTextAccessible* mAccWithCaret;
 134   WeakPtr<dom::Selection> mCurrCtrlNormalSel;
 135   WeakPtr<dom::Selection> mCurrCtrlSpellSel;
 136 };
 137
 138 }  // namespace a11y
 139 }  // namespace mozilla
 140
 141 #endif