content/browser/gamepad/gamepad_provider.h

   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
  22 namespace base {
  23 class MessageLoopProxy;
  24 class Thread;
  25 }
  26
  27 namespace content {
  28
  29 class GamepadDataFetcher;
  30 struct GamepadHardwareBuffer;
  31
  32 class 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_