ui/events/ozone/evdev/event_modifiers_evdev.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_EVENTS_OZONE_EVDEV_EVENT_MODIFIERS_EVDEV_H_
   6 #define UI_EVENTS_OZONE_EVDEV_EVENT_MODIFIERS_EVDEV_H_
   7
   8 #include "base/basictypes.h"
   9 #include "ui/events/ozone/evdev/events_ozone_evdev_export.h"
  10
  11 namespace ui {
  12
  13 enum {
  14   EVDEV_MODIFIER_NONE,
  15   EVDEV_MODIFIER_CAPS_LOCK,
  16   EVDEV_MODIFIER_SHIFT,
  17   EVDEV_MODIFIER_CONTROL,
  18   EVDEV_MODIFIER_ALT,
  19   EVDEV_MODIFIER_LEFT_MOUSE_BUTTON,
  20   EVDEV_MODIFIER_MIDDLE_MOUSE_BUTTON,
  21   EVDEV_MODIFIER_RIGHT_MOUSE_BUTTON,
  22   EVDEV_MODIFIER_BACK_MOUSE_BUTTON,
  23   EVDEV_MODIFIER_FORWARD_MOUSE_BUTTON,
  24   EVDEV_MODIFIER_COMMAND,
  25   EVDEV_MODIFIER_ALTGR,
  26   EVDEV_MODIFIER_MOD3,
  27   EVDEV_NUM_MODIFIERS
  28 };
  29
  30 // Modifier key state for Evdev.
  31 //
  32 // Chrome relies on the underlying OS to interpret modifier keys such as Shift,
  33 // Ctrl, and Alt. The Linux input subsystem does not assign any special meaning
  34 // to these keys, so this work must happen at a higher layer (normally X11 or
  35 // the console driver). When using evdev directly, we must do it ourselves.
  36 //
  37 // The modifier state is shared between all input devices connected to the
  38 // system. This is to support actions such as Shift-Clicking that use multiple
  39 // devices.
  40 //
  41 // Normally a modifier is set if any of the keys or buttons assigned to it are
  42 // currently pressed. However some keys toggle a persistent "lock" for the
  43 // modifier instead, such as CapsLock. If a modifier is "locked" then its state
  44 // is inverted until it is unlocked.
  45 class EVENTS_OZONE_EVDEV_EXPORT EventModifiersEvdev {
  46  public:
  47   EventModifiersEvdev();
  48   ~EventModifiersEvdev();
  49
  50   // Record key press or release for regular modifier key (shift, alt, etc).
  51   void UpdateModifier(unsigned int modifier, bool down);
  52
  53   // Record key press or release for locking modifier key (caps lock).
  54   void UpdateModifierLock(unsigned int modifier, bool down);
  55
  56   // Directly set the state of a locking modifier key (caps lock).
  57   void SetModifierLock(unsigned int modifier, bool locked);
  58
  59   // Return current flags to use for incoming events.
  60   int GetModifierFlags();
  61
  62   // Return the mask for the specified modifier.
  63   static int GetEventFlagFromModifier(unsigned int modifier);
  64
  65  private:
  66   // Count of keys pressed for each modifier.
  67   int modifiers_down_[EVDEV_NUM_MODIFIERS];
  68
  69   // Mask of modifier flags currently "locked".
  70   int modifier_flags_locked_;
  71
  72   // Mask of modifier flags currently active (nonzero keys pressed xor locked).
  73   int modifier_flags_;
  74
  75   // Update modifier_flags_ from modifiers_down_ and modifier_flags_locked_.
  76   void UpdateFlags(unsigned int modifier);
  77
  78   DISALLOW_COPY_AND_ASSIGN(EventModifiersEvdev);
  79 };
  80
  81 }  // namspace ui
  82
  83 #endif  // UI_EVENTS_OZONE_EVDEV_EVENT_MODIFIERS_EVDEV_H_