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 CONTENT_BROWSER_GAMEPAD_GAMEPAD_PROVIDER_H_
6#define CONTENT_BROWSER_GAMEPAD_GAMEPAD_PROVIDER_H_
7
8#include <utility>
9#include <vector>
10
11#include "base/callback_forward.h"
12#include "base/memory/ref_counted.h"
13#include "base/memory/scoped_ptr.h"
14#include "base/memory/shared_memory.h"
15#include "base/memory/weak_ptr.h"
16#include "base/message_loop/message_loop_proxy.h"
17#include "base/synchronization/lock.h"
18#include "base/system_monitor/system_monitor.h"
19#include "content/common/content_export.h"
20#include "third_party/WebKit/public/platform/WebGamepads.h"
21
22namespace base {
23class MessageLoopProxy;
24class Thread;
25}
26
27namespace content {
28
29class GamepadDataFetcher;
30struct GamepadHardwareBuffer;
31
32class CONTENT_EXPORT GamepadProvider :
33  public base::SystemMonitor::DevicesChangedObserver {
34 public:
35  GamepadProvider();
36
37  // Manually specifies the data fetcher. Used for testing.
38  explicit GamepadProvider(scoped_ptr<GamepadDataFetcher> fetcher);
39
40  virtual ~GamepadProvider();
41
42  // Returns the shared memory handle of the gamepad data duplicated into the
43  // given process.
44  base::SharedMemoryHandle GetSharedMemoryHandleForProcess(
45      base::ProcessHandle renderer_process);
46
47  void GetCurrentGamepadData(blink::WebGamepads* data);
48
49  // Pause and resume the background polling thread. Can be called from any
50  // thread.
51  void Pause();
52  void Resume();
53
54  // Registers the given closure for calling when the user has interacted with
55  // the device. This callback will only be issued once.
56  void RegisterForUserGesture(const base::Closure& closure);
57
58  // base::SystemMonitor::DevicesChangedObserver implementation.
59  virtual void OnDevicesChanged(base::SystemMonitor::DeviceType type) OVERRIDE;
60
61 private:
62  void Initialize(scoped_ptr<GamepadDataFetcher> fetcher);
63
64  // Method for setting up the platform-specific data fetcher. Takes ownership
65  // of |fetcher|.
66  void DoInitializePollingThread(scoped_ptr<GamepadDataFetcher> fetcher);
67
68  // Method for sending pause hints to the low-level data fetcher. Runs on
69  // polling_thread_.
70  void SendPauseHint(bool paused);
71
72  // Method for polling a GamepadDataFetcher. Runs on the polling_thread_.
73  void DoPoll();
74  void ScheduleDoPoll();
75
76  void OnGamepadConnectionChange(bool connected,
77                                 int index,
78                                 const blink::WebGamepad& pad);
79  void DispatchGamepadConnectionChange(bool connected,
80                                       int index,
81                                       const blink::WebGamepad& pad);
82
83  GamepadHardwareBuffer* SharedMemoryAsHardwareBuffer();
84
85  // Checks the gamepad state to see if the user has interacted with it.
86  void CheckForUserGesture();
87
88  enum { kDesiredSamplingIntervalMs = 16 };
89
90  // Keeps track of when the background thread is paused. Access to is_paused_
91  // must be guarded by is_paused_lock_.
92  base::Lock is_paused_lock_;
93  bool is_paused_;
94
95  // Keep track of when a polling task is schedlued, so as to prevent us from
96  // accidentally scheduling more than one at any time, when rapidly toggling
97  // |is_paused_|.
98  bool have_scheduled_do_poll_;
99
100  // Lists all observers registered for user gestures, and the thread which
101  // to issue the callbacks on. Since we always issue the callback on the
102  // thread which the registration happened, and this class lives on the I/O
103  // thread, the message loop proxies will normally just be the I/O thread.
104  // However, this will be the main thread for unit testing.
105  base::Lock user_gesture_lock_;
106  struct ClosureAndThread {
107    ClosureAndThread(const base::Closure& c,
108                     const scoped_refptr<base::MessageLoopProxy>& m);
109    ~ClosureAndThread();
110
111    base::Closure closure;
112    scoped_refptr<base::MessageLoopProxy> message_loop;
113  };
114  typedef std::vector<ClosureAndThread> UserGestureObserverVector;
115  UserGestureObserverVector user_gesture_observers_;
116
117  // Updated based on notification from SystemMonitor when the system devices
118  // have been updated, and this notification is passed on to the data fetcher
119  // to enable it to avoid redundant (and possibly expensive) is-connected
120  // tests. Access to devices_changed_ must be guarded by
121  // devices_changed_lock_.
122  base::Lock devices_changed_lock_;
123  bool devices_changed_;
124
125  bool ever_had_user_gesture_;
126
127  class PadState {
128   public:
129    PadState() {
130      SetDisconnected();
131    }
132
133    bool Match(const blink::WebGamepad& pad) const;
134    void SetPad(const blink::WebGamepad& pad);
135    void SetDisconnected();
136    void AsWebGamepad(blink::WebGamepad* pad);
137
138    bool connected() const { return connected_; }
139
140   private:
141    bool connected_;
142    unsigned axes_length_;
143    unsigned buttons_length_;
144    blink::WebUChar id_[blink::WebGamepad::idLengthCap];
145    blink::WebUChar mapping_[blink::WebGamepad::mappingLengthCap];
146  };
147
148  // Used to detect connections and disconnections.
149  scoped_ptr<PadState[]> pad_states_;
150
151  // Only used on the polling thread.
152  scoped_ptr<GamepadDataFetcher> data_fetcher_;
153
154  base::Lock shared_memory_lock_;
155  base::SharedMemory gamepad_shared_memory_;
156
157  // Polling is done on this background thread.
158  scoped_ptr<base::Thread> polling_thread_;
159
160  static GamepadProvider* instance_;
161
162  DISALLOW_COPY_AND_ASSIGN(GamepadProvider);
163};
164
165}  // namespace content
166
167#endif  // CONTENT_BROWSER_GAMEPAD_GAMEPAD_PROVIDER_H_
168