accelerator.h revision 5821806d5e7f356e8fa4b058a389a808ea183019 
1// Copyright (c) 2012 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// This class describe a keyboard accelerator (or keyboard shortcut).
6// Keyboard accelerators are registered with the FocusManager.
7// It has a copy constructor and assignment operator so that it can be copied.
8// It also defines the < operator so that it can be used as a key in a std::map.
9//
10
11#ifndef UI_BASE_ACCELERATORS_ACCELERATOR_H_
12#define UI_BASE_ACCELERATORS_ACCELERATOR_H_
13
14#include "base/string16.h"
15#include "ui/base/events/event_constants.h"
16#include "ui/base/keycodes/keyboard_codes.h"
17#include "ui/base/ui_export.h"
18
19namespace ui {
20
21// This is a cross-platform base class for accelerator keys used in menus. It is
22// meant to be subclassed for concrete toolkit implementations.
23class UI_EXPORT Accelerator {
24 public:
25  Accelerator();
26  Accelerator(ui::KeyboardCode keycode, int modifiers);
27  Accelerator(const Accelerator& accelerator);
28  ~Accelerator();
29
30  Accelerator& operator=(const Accelerator& accelerator);
31
32  // We define the < operator so that the KeyboardShortcut can be used as a key
33  // in a std::map.
34  bool operator <(const Accelerator& rhs) const;
35
36  bool operator ==(const Accelerator& rhs) const;
37
38  bool operator !=(const Accelerator& rhs) const;
39
40  ui::KeyboardCode key_code() const { return key_code_; }
41
42  // Sets the event type if the accelerator should be processed on an event
43  // other than ui::ET_KEY_PRESSED.
44  void set_type(ui::EventType type) { type_ = type; }
45  ui::EventType type() const { return type_; }
46
47  int modifiers() const { return modifiers_; }
48
49  bool IsShiftDown() const;
50  bool IsCtrlDown() const;
51  bool IsAltDown() const;
52  bool IsCmdDown() const;
53
54  // Returns a string with the localized shortcut if any.
55  string16 GetShortcutText() const;
56
57 protected:
58  // The keycode (VK_...).
59  KeyboardCode key_code_;
60
61  // The event type (usually ui::ET_KEY_PRESSED).
62  EventType type_;
63
64  // The state of the Shift/Ctrl/Alt keys (platform-dependent).
65  int modifiers_;
66};
67
68// An interface that classes that want to register for keyboard accelerators
69// should implement.
70class UI_EXPORT AcceleratorTarget {
71 public:
72  // Should return true if the accelerator was processed.
73  virtual bool AcceleratorPressed(const Accelerator& accelerator) = 0;
74
75  // Should return true if the target can handle the accelerator events. The
76  // AcceleratorPressed method is invoked only for targets for which
77  // CanHandleAccelerators returns true.
78  virtual bool CanHandleAccelerators() const = 0;
79
80 protected:
81  virtual ~AcceleratorTarget() {}
82};
83
84// Since accelerator code is one of the few things that can't be cross platform
85// in the chrome UI, separate out just the GetAcceleratorForCommandId() from
86// the menu delegates.
87class AcceleratorProvider {
88 public:
89  // Gets the accelerator for the specified command id. Returns true if the
90  // command id has a valid accelerator, false otherwise.
91  virtual bool GetAcceleratorForCommandId(int command_id,
92                                          ui::Accelerator* accelerator) = 0;
93
94 protected:
95  virtual ~AcceleratorProvider() {}
96};
97
98}  // namespace ui
99
100#endif  // UI_BASE_ACCELERATORS_ACCELERATOR_H_
101