Refactored gamepad polling to support dynamic sources

device/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 DEVICE_GAMEPAD_GAMEPAD_PROVIDER_H_
 #define DEVICE_GAMEPAD_GAMEPAD_PROVIDER_H_
 
 #include <memory>
 #include <utility>
 #include <vector>
 
 #include "base/callback_forward.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/shared_memory.h"
-#include "base/memory/weak_ptr.h"
 #include "base/synchronization/lock.h"
 #include "base/system_monitor/system_monitor.h"
 #include "device/gamepad/gamepad_export.h"
+#include "device/gamepad/gamepad_pad_state_provider.h"
 #include "device/gamepad/gamepad_shared_buffer.h"
+
 #include "third_party/WebKit/public/platform/WebGamepads.h"
 
 namespace base {
 class SingleThreadTaskRunner;
 class Thread;
 }
 
 namespace device {
 
 class GamepadDataFetcher;
 
 class DEVICE_GAMEPAD_EXPORT GamepadConnectionChangeClient {
  public:
   virtual void OnGamepadConnectionChange(bool connected,
                                          int index,
                                          const blink::WebGamepad& pad) = 0;
 };
 
 class DEVICE_GAMEPAD_EXPORT GamepadProvider
-    : public base::SystemMonitor::DevicesChangedObserver {
+    : public GamepadPadStateProvider,
+      public base::SystemMonitor::DevicesChangedObserver {
  public:
   explicit GamepadProvider(
       std::unique_ptr<GamepadSharedBuffer> buffer,
       GamepadConnectionChangeClient* connection_change_client);
 
   // Manually specifies the data fetcher. Used for testing.
   explicit GamepadProvider(
       std::unique_ptr<GamepadSharedBuffer> buffer,
       GamepadConnectionChangeClient* connection_change_client,
       std::unique_ptr<GamepadDataFetcher> fetcher);
 
   ~GamepadProvider() override;
 
   // Returns the shared memory handle of the gamepad data duplicated into the
   // given process.
   base::SharedMemoryHandle GetSharedMemoryHandleForProcess(
       base::ProcessHandle renderer_process);
 
+  void AddGamepadDataFetcher(GamepadDataFetcher* fetcher);
+  void RemoveGamepadDataFetcher(GamepadDataFetcher* fetcher);
+
   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.
   void OnDevicesChanged(base::SystemMonitor::DeviceType type) override;
 
+  // Add a gamepad data fetcher. Takes ownership of |fetcher|.
+  void AddGamepadDataFetcher(std::unique_ptr<GamepadDataFetcher> fetcher);
+
+  // Remove gamepad data fetchers with the given source.
+  void RemoveSourceGamepadDataFetcher(GamepadSource source);
+
+  void SetSanitizationEnabled(bool sanitize) { sanitize_ = sanitize; }
+
  private:
   void Initialize(std::unique_ptr<GamepadDataFetcher> fetcher);
 
   // Method for setting up the platform-specific data fetcher. Takes ownership
   // of |fetcher|.
-  void DoInitializePollingThread(std::unique_ptr<GamepadDataFetcher> fetcher);
+  void DoAddGamepadDataFetcher(std::unique_ptr<GamepadDataFetcher> fetcher);
+  void DoRemoveSourceGamepadDataFetcher(GamepadSource source);
 
   // 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,
@@ skipping 35 matching lines @@
 
   // 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_;
 
   bool ever_had_user_gesture_;
-
-  class PadState {
-   public:
-    PadState() { SetDisconnected(); }
-
-    bool Match(const blink::WebGamepad& pad) const;
-    void SetPad(const blink::WebGamepad& pad);
-    void SetDisconnected();
-    void AsWebGamepad(blink::WebGamepad* pad);
-
-    bool connected() const { return connected_; }
-
-   private:
-    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.
-  std::unique_ptr<PadState[]> pad_states_;
+  bool sanitize_;
 
   // Only used on the polling thread.
-  std::unique_ptr<GamepadDataFetcher> data_fetcher_;
+  typedef std::vector<std::unique_ptr<GamepadDataFetcher>> GamepadFetcherVector;
+  GamepadFetcherVector data_fetchers_;
 
   base::Lock shared_memory_lock_;
   std::unique_ptr<GamepadSharedBuffer> gamepad_shared_buffer_;
 
   // Polling is done on this background thread.
   std::unique_ptr<base::Thread> polling_thread_;
 
   GamepadConnectionChangeClient* connection_change_client_;
 
-  static GamepadProvider* instance_;
-
   DISALLOW_COPY_AND_ASSIGN(GamepadProvider);
 };
 
 }  // namespace device
 
 #endif  // DEVICE_GAMEPAD_GAMEPAD_PROVIDER_H_