Gamepad API: add support for connection events

content/browser/gamepad/gamepad_provider.h

 // Copyright (c) 2012 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 CONTENT_BROWSER_GAMEPAD_GAMEPAD_PROVIDER_H_
 #define CONTENT_BROWSER_GAMEPAD_GAMEPAD_PROVIDER_H_
 
 #include <utility>
 #include <vector>
 
 #include "base/callback_forward.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/shared_memory.h"
 #include "base/memory/weak_ptr.h"
 #include "base/message_loop/message_loop_proxy.h"
 #include "base/synchronization/lock.h"
 #include "base/system_monitor/system_monitor.h"
 #include "content/common/content_export.h"
+#include "third_party/WebKit/public/platform/WebGamepads.h"
 
 namespace base {
 class MessageLoopProxy;
 class Thread;
 }
 
 namespace content {
 
 class GamepadDataFetcher;
 struct GamepadHardwareBuffer;
 
 class CONTENT_EXPORT GamepadProvider :
   public base::SystemMonitor::DevicesChangedObserver {
  public:
   GamepadProvider();
 
   // Manually specifies the data fetcher. Used for testing.
   explicit GamepadProvider(scoped_ptr<GamepadDataFetcher> fetcher);
 
   virtual ~GamepadProvider();
 
   // Returns the shared memory handle of the gamepad data duplicated into the
   // given process.
   base::SharedMemoryHandle GetSharedMemoryHandleForProcess(
       base::ProcessHandle renderer_process);
 
+  void GetCurrentGamepadData(blink::WebGamepads* data);
+
   // Pause and resume the background polling thread. Can be called from any
   // thread.
   void Pause();
   void Resume();
 
   // Registers the given closure for calling when the user has interacted with
   // the device. This callback will only be issued once.
   void RegisterForUserGesture(const base::Closure& closure);
 
   // base::SystemMonitor::DevicesChangedObserver implementation.
   virtual void OnDevicesChanged(base::SystemMonitor::DeviceType type) OVERRIDE;
 
  private:
   void Initialize(scoped_ptr<GamepadDataFetcher> fetcher);
 
   // Method for setting up the platform-specific data fetcher. Takes ownership
   // of |fetcher|.
   void DoInitializePollingThread(scoped_ptr<GamepadDataFetcher> fetcher);
 
   // Method for sending pause hints to the low-level data fetcher. Runs on
   // polling_thread_.
   void SendPauseHint(bool paused);
 
   // Method for polling a GamepadDataFetcher. Runs on the polling_thread_.
   void DoPoll();
   void ScheduleDoPoll();
 
+  void OnGamepadConnectionChange(bool connected,
+                                 int index,
+                                 const blink::WebGamepad& pad);
+  void DispatchGamepadConnectionChange(bool connected,
+                                       int index,
+                                       const blink::WebGamepad& pad);
+
   GamepadHardwareBuffer* SharedMemoryAsHardwareBuffer();
 
   // Checks the gamepad state to see if the user has interacted with it.
   void CheckForUserGesture();
 
   enum { kDesiredSamplingIntervalMs = 16 };
 
   // Keeps track of when the background thread is paused. Access to is_paused_
   // must be guarded by is_paused_lock_.
   base::Lock is_paused_lock_;
@@ skipping 22 matching lines @@
   UserGestureObserverVector user_gesture_observers_;
 
   // Updated based on notification from SystemMonitor when the system devices
   // have been updated, and this notification is passed on to the data fetcher
   // to enable it to avoid redundant (and possibly expensive) is-connected
   // tests. Access to devices_changed_ must be guarded by
   // devices_changed_lock_.
   base::Lock devices_changed_lock_;
   bool devices_changed_;
 
-  // When polling_thread_ is running, members below are only to be used
-  // from that thread.
+  bool ever_had_user_gesture_;
+
+  struct PadState {

[jam, 2014/05/05 21:19:09]

per style guide, this should be a class and not struct. this means moving the
members to the private section and having getters.

+    PadState() {
+      SetDisconnected();
+    }
+
+    bool Match(const blink::WebGamepad& pad) const;
+    void SetPad(const blink::WebGamepad& pad);
+    void SetDisconnected();
+    void AsWebGamepad(blink::WebGamepad* pad);
+
+    bool connected;
+    unsigned axes_length;
+    unsigned buttons_length;
+    blink::WebUChar id[blink::WebGamepad::idLengthCap];
+    blink::WebUChar mapping[blink::WebGamepad::mappingLengthCap];
+  };
+
+  // Used to detect connections and disconnections.
+  scoped_ptr<PadState[]> pad_states_;
+
+  // Only used on the polling thread.
   scoped_ptr<GamepadDataFetcher> data_fetcher_;
+
+  base::Lock shared_memory_lock_;
   base::SharedMemory gamepad_shared_memory_;
 
   // Polling is done on this background thread.
   scoped_ptr<base::Thread> polling_thread_;
 
   static GamepadProvider* instance_;
 
   DISALLOW_COPY_AND_ASSIGN(GamepadProvider);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_GAMEPAD_GAMEPAD_PROVIDER_H_