1 // Copyright 2013 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 MEDIA_BASE_USER_INPUT_MONITOR_H_ 6 #define MEDIA_BASE_USER_INPUT_MONITOR_H_ 7 8 #include "base/memory/ref_counted.h" 9 #include "base/memory/scoped_ptr.h" 10 #include "base/observer_list_threadsafe.h" 11 #include "base/synchronization/lock.h" 12 #include "media/base/media_export.h" 13 14 struct SkIPoint; 15 16 namespace base { 17 class SingleThreadTaskRunner; 18 } // namespace base 19 20 namespace media { 21 22 // Monitors and notifies about mouse movements and keyboard events. 23 // Thread safe. The listeners are called on the thread where the listeners are 24 // added. 25 class MEDIA_EXPORT UserInputMonitor { 26 public: 27 // The interface to receive mouse movement events. 28 class MEDIA_EXPORT MouseEventListener { 29 public: 30 // |position| is the new mouse position. 31 virtual void OnMouseMoved(const SkIPoint& position) = 0; 32 33 protected: ~MouseEventListener()34 virtual ~MouseEventListener() {} 35 }; 36 typedef ObserverListThreadSafe<UserInputMonitor::MouseEventListener> 37 MouseListenerList; 38 39 UserInputMonitor(); 40 virtual ~UserInputMonitor(); 41 42 // Creates a platform-specific instance of UserInputMonitor. 43 // |io_task_runner| is the task runner for an IO thread. 44 // |ui_task_runner| is the task runner for a UI thread. 45 static scoped_ptr<UserInputMonitor> Create( 46 const scoped_refptr<base::SingleThreadTaskRunner>& io_task_runner, 47 const scoped_refptr<base::SingleThreadTaskRunner>& ui_task_runner); 48 49 // The same |listener| should only be added once. 50 // The clients should make sure to call Remove*Listener before |listener| is 51 // destroyed. 52 void AddMouseListener(MouseEventListener* listener); 53 void RemoveMouseListener(MouseEventListener* listener); 54 55 // A caller must call EnableKeyPressMonitoring and 56 // DisableKeyPressMonitoring in pair. 57 void EnableKeyPressMonitoring(); 58 void DisableKeyPressMonitoring(); 59 60 // Returns the number of keypresses. The starting point from when it is 61 // counted is not guaranteed, but consistent within the pair of calls of 62 // EnableKeyPressMonitoring and DisableKeyPressMonitoring. So a caller can 63 // use the difference between the values returned at two times to get the 64 // number of keypresses happened within that time period, but should not make 65 // any assumption on the initial value. 66 virtual size_t GetKeyPressCount() const = 0; 67 68 protected: mouse_listeners()69 scoped_refptr<MouseListenerList> mouse_listeners() { 70 return mouse_listeners_; 71 } 72 73 private: 74 virtual void StartKeyboardMonitoring() = 0; 75 virtual void StopKeyboardMonitoring() = 0; 76 virtual void StartMouseMonitoring() = 0; 77 virtual void StopMouseMonitoring() = 0; 78 79 base::Lock lock_; 80 size_t key_press_counter_references_; 81 size_t mouse_listeners_count_; 82 scoped_refptr<MouseListenerList> mouse_listeners_; 83 84 DISALLOW_COPY_AND_ASSIGN(UserInputMonitor); 85 }; 86 87 } // namespace media 88 89 #endif // MEDIA_BASE_USER_INPUT_MONITOR_H_ 90