ui/base/accelerators/accelerator_history.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef UI_BASE_ACCELERATORS_ACCELERATOR_HISTORY_H_
   6 #define UI_BASE_ACCELERATORS_ACCELERATOR_HISTORY_H_
   7
   8 #include "base/memory/singleton.h"
   9 #include "ui/base/accelerators/accelerator.h"
  10 #include "ui/base/ui_base_export.h"
  11 #include "ui/events/event.h"
  12 #include "ui/events/event_handler.h"
  13
  14 namespace ui {
  15
  16 // Keeps track of the system-wide current and the most recent previous
  17 // key accelerators.
  18 class UI_BASE_EXPORT AcceleratorHistory {
  19  public:
  20   AcceleratorHistory();
  21   ~AcceleratorHistory();
  22
  23   // Returns the most recent recorded accelerator.
  24   const Accelerator& current_accelerator() const {
  25     return current_accelerator_;
  26   }
  27
  28   // Returns the most recent previously recorded accelerator that is different
  29   // than the current.
  30   const Accelerator& previous_accelerator() const {
  31     return previous_accelerator_;
  32   }
  33
  34   // Stores the given |accelerator| only if it's different than the currently
  35   // stored one.
  36   void StoreCurrentAccelerator(const Accelerator& accelerator);
  37
  38  private:
  39   Accelerator current_accelerator_;
  40   Accelerator previous_accelerator_;
  41
  42   DISALLOW_COPY_AND_ASSIGN(AcceleratorHistory);
  43 };
  44
  45 }; // namespace ui
  46
  47 #endif  // UI_BASE_ACCELERATORS_ACCELERATOR_HISTORY_H_