tor-browser

The Tor Browser
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SelectionManager.h (3839B)

      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 "nsISelectionController.h"
     10 #include "nsISelectionListener.h"
     11 #include "mozilla/WeakPtr.h"
     12 
     13 namespace mozilla {
     14 
     15 class PresShell;
     16 
     17 namespace dom {
     18 class AbstractRange;
     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  inline void ResetCaretOffset() {
     99    mCaretOffset = -1;
    100    mAccWithCaret = nullptr;
    101  }
    102 
    103  /**
    104   * Called by DOM when a selection range is added/removed.
    105   * We need this because nsISelectionListener isn't sufficient for spelling
    106   * errors, etc., since it only tells us that there was a change, not which
    107   * range changed. We don't want to unnecessarily push a cache update for all
    108   * Accessibles in the entire selection.
    109   * Returns false if these notifications aren't required for this selection
    110   * type at this time.
    111   */
    112  static bool SelectionRangeChanged(SelectionType aType,
    113                                    const dom::AbstractRange& aRange);
    114 
    115  ~SelectionManager();
    116 
    117 protected:
    118  SelectionManager();
    119 
    120  /**
    121   * Process DOM selection change. Fire selection and caret move events.
    122   */
    123  void ProcessSelectionChanged(SelData* aSelData);
    124 
    125 private:
    126  // Currently focused control.
    127  int32_t mCaretOffset;
    128  HyperTextAccessible* mAccWithCaret;
    129  WeakPtr<dom::Selection> mCurrCtrlNormalSel;
    130 };
    131 
    132 }  // namespace a11y
    133 }  // namespace mozilla
    134 
    135 #endif