ash/wm/window_cycle_list.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 ASH_WM_WINDOW_CYCLE_LIST_H_
   6 #define ASH_WM_WINDOW_CYCLE_LIST_H_
   7
   8 #include <vector>
   9
  10 #include "ash/ash_export.h"
  11 #include "ash/wm/window_cycle_controller.h"
  12 #include "base/basictypes.h"
  13 #include "base/compiler_specific.h"
  14 #include "base/memory/scoped_ptr.h"
  15 #include "ui/aura/window_observer.h"
  16
  17 namespace ash {
  18
  19 class ScopedShowWindow;
  20
  21 // Tracks a set of Windows that can be stepped through. This class is used by
  22 // the WindowCycleController.
  23 class ASH_EXPORT WindowCycleList : public aura::WindowObserver {
  24  public:
  25   typedef std::vector<aura::Window*> WindowList;
  26
  27   explicit WindowCycleList(const WindowList& windows);
  28   ~WindowCycleList() override;
  29
  30   bool empty() const { return windows_.empty(); }
  31
  32   // Cycles to the next or previous window based on |direction|.
  33   void Step(WindowCycleController::Direction direction);
  34
  35   const WindowList& windows() const { return windows_; }
  36
  37  private:
  38   // aura::WindowObserver overrides:
  39   // There is a chance a window is destroyed, for example by JS code. We need to
  40   // take care of that even if it is not intended for the user to close a window
  41   // while window cycling.
  42   void OnWindowDestroyed(aura::Window* window) override;
  43
  44   // List of weak pointers to windows to use while cycling with the keyboard.
  45   // List is built when the user initiates the gesture (i.e. hits alt-tab the
  46   // first time) and is emptied when the gesture is complete (i.e. releases the
  47   // alt key).
  48   WindowList windows_;
  49
  50   // Current position in the |windows_|
  51   int current_index_;
  52
  53   // Wrapper for the window brought to the front.
  54   scoped_ptr<ScopedShowWindow> showing_window_;
  55
  56   DISALLOW_COPY_AND_ASSIGN(WindowCycleList);
  57 };
  58
  59 }  // namespace ash
  60
  61 #endif  // ASH_WM_WINDOW_CYCLE_LIST_H_