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 #ifndef CHROME_BROWSER_CHROMEOS_SYSTEM_KEY_EVENT_LISTENER_H_ 6 #define CHROME_BROWSER_CHROMEOS_SYSTEM_KEY_EVENT_LISTENER_H_ 7 8 #include "base/memory/singleton.h" 9 #include "base/message_loop/message_loop.h" 10 11 typedef union _XEvent XEvent; 12 13 namespace chromeos { 14 15 class SystemKeyEventListener : public base::MessageLoopForUI::Observer { 16 public: 17 // Observer for caps lock state changes. 18 class CapsLockObserver { 19 public: 20 virtual void OnCapsLockChange(bool enabled) = 0; 21 22 protected: 23 CapsLockObserver() {} 24 virtual ~CapsLockObserver() {} 25 26 DISALLOW_COPY_AND_ASSIGN(CapsLockObserver); 27 }; 28 29 // Observer for modifier keys' state changes. 30 class ModifiersObserver { 31 public: 32 enum { 33 SHIFT_PRESSED = 1, 34 CTRL_PRESSED = 1 << 1, 35 ALT_PRESSED = 1 << 2, 36 }; 37 38 // |pressed_modifiers| is a bitmask of SHIFT_PRESSED, CTRL_PRESSED and 39 // ALT_PRESSED. 40 virtual void OnModifiersChange(int pressed_modifiers) = 0; 41 42 protected: 43 ModifiersObserver() {} 44 virtual ~ModifiersObserver() {} 45 46 DISALLOW_COPY_AND_ASSIGN(ModifiersObserver); 47 }; 48 49 static void Initialize(); 50 static void Shutdown(); 51 // GetInstance returns NULL if not initialized or if already shutdown. 52 static SystemKeyEventListener* GetInstance(); 53 54 void Stop(); 55 56 void AddCapsLockObserver(CapsLockObserver* observer); 57 void AddModifiersObserver(ModifiersObserver* observer); 58 void RemoveCapsLockObserver(CapsLockObserver* observer); 59 void RemoveModifiersObserver(ModifiersObserver* observer); 60 61 private: 62 // Defines the delete on exit Singleton traits we like. Best to have this 63 // and const/dest private as recommended for Singletons. 64 friend struct DefaultSingletonTraits<SystemKeyEventListener>; 65 friend class SystemKeyEventListenerTest; 66 67 SystemKeyEventListener(); 68 virtual ~SystemKeyEventListener(); 69 70 // MessageLoopForUI::Observer overrides. 71 virtual base::EventStatus WillProcessEvent( 72 const base::NativeEvent& event) OVERRIDE; 73 virtual void DidProcessEvent(const base::NativeEvent& event) OVERRIDE; 74 75 void OnCapsLock(bool enabled); 76 void OnModifiers(int state); 77 78 // Returns true if the event was processed, false otherwise. 79 virtual bool ProcessedXEvent(XEvent* xevent); 80 81 bool stopped_; 82 83 unsigned int num_lock_mask_; 84 bool caps_lock_is_on_; 85 int pressed_modifiers_; 86 ObserverList<CapsLockObserver> caps_lock_observers_; 87 ObserverList<ModifiersObserver> modifiers_observers_; 88 89 // Base X ID for events from the XKB extension. 90 int xkb_event_base_; 91 92 DISALLOW_COPY_AND_ASSIGN(SystemKeyEventListener); 93 }; 94 95 } // namespace chromeos 96 97 #endif // CHROME_BROWSER_CHROMEOS_SYSTEM_KEY_EVENT_LISTENER_H_ 98