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- // Copyright 2014 The Chromium Authors. All rights reserved.
- // Use of this source code is governed by a BSD-style license that can be
- // found in the LICENSE file.
- #ifndef UI_EVENTS_EVENT_MODIFIERS_H_
- #define UI_EVENTS_EVENT_MODIFIERS_H_
- #include "ui/events/events_export.h"
- namespace ui {
- enum {
- MODIFIER_NONE,
- MODIFIER_SHIFT,
- MODIFIER_CONTROL,
- MODIFIER_ALT,
- MODIFIER_COMMAND,
- MODIFIER_ALTGR,
- MODIFIER_MOD3,
- MODIFIER_CAPS_LOCK,
- MODIFIER_LEFT_MOUSE_BUTTON,
- MODIFIER_MIDDLE_MOUSE_BUTTON,
- MODIFIER_RIGHT_MOUSE_BUTTON,
- MODIFIER_BACK_MOUSE_BUTTON,
- MODIFIER_FORWARD_MOUSE_BUTTON,
- MODIFIER_NUM_MODIFIERS
- };
- // Modifier key state for Evdev.
- //
- // Chrome relies on the underlying OS to interpret modifier keys such as Shift,
- // Ctrl, and Alt. The Linux input subsystem does not assign any special meaning
- // to these keys, so this work must happen at a higher layer (normally X11 or
- // the console driver). When using evdev directly, we must do it ourselves.
- //
- // The modifier state is shared between all input devices connected to the
- // system. This is to support actions such as Shift-Clicking that use multiple
- // devices.
- //
- // Normally a modifier is set if any of the keys or buttons assigned to it are
- // currently pressed. However some keys toggle a persistent "lock" for the
- // modifier instead, such as CapsLock. If a modifier is "locked" then its state
- // is inverted until it is unlocked.
- class EVENTS_EXPORT EventModifiers {
- public:
- EventModifiers();
- EventModifiers(const EventModifiers&) = delete;
- EventModifiers& operator=(const EventModifiers&) = delete;
- ~EventModifiers();
- // Record key press or release for regular modifier key (shift, alt, etc).
- void UpdateModifier(unsigned int modifier, bool down);
- // Record key press or release for locking modifier key (caps lock).
- void UpdateModifierLock(unsigned int modifier, bool down);
- // Directly set the state of a locking modifier key (caps lock).
- void SetModifierLock(unsigned int modifier, bool locked);
- // Return current flags to use for incoming events.
- int GetModifierFlags();
- // Release modifier keys.
- void ResetKeyboardModifiers();
- // Return the mask for the specified modifier.
- static int GetEventFlagFromModifier(unsigned int modifier);
- // Return the modifier for the specified mask.
- static int GetModifierFromEventFlag(int flag);
- private:
- // Count of keys pressed for each modifier.
- int modifiers_down_[MODIFIER_NUM_MODIFIERS];
- // Mask of modifier flags currently "locked".
- int modifier_flags_locked_ = 0;
- // Mask of modifier flags currently active (nonzero keys pressed xor locked).
- int modifier_flags_ = 0;
- // Update modifier_flags_ from modifiers_down_ and modifier_flags_locked_.
- void UpdateFlags(unsigned int modifier);
- };
- } // namespace ui
- #endif // UI_EVENTS_EVENT_MODIFIERS_H_
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