content/browser/gamepad/gamepad_service.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_SERVICE_H
   6 #define CONTENT_BROWSER_GAMEPAD_GAMEPAD_SERVICE_H
   7
   8 #include "base/basictypes.h"
   9 #include "base/callback_forward.h"
  10 #include "base/memory/scoped_ptr.h"
  11 #include "base/memory/shared_memory.h"
  12 #include "base/memory/singleton.h"
  13 #include "base/threading/thread_checker.h"
  14 #include "content/common/content_export.h"
  15
  16 namespace content {
  17
  18 class GamepadDataFetcher;
  19 class GamepadProvider;
  20 class GamepadServiceTestConstructor;
  21 class RenderProcessHost;
  22
  23 // Owns the GamepadProvider (the background polling thread) and keeps track of
  24 // the number of consumers currently using the data (and pausing the provider
  25 // when not in use).
  26 class CONTENT_EXPORT GamepadService {
  27  public:
  28   // Returns the GamepadService singleton.
  29   static GamepadService* GetInstance();
  30
  31   // Increments the number of users of the provider. The Provider is running
  32   // when there's > 0 users, and is paused when the count drops to 0.
  33   //
  34   // Must be called on the I/O thread.
  35   void AddConsumer();
  36
  37   // Removes a consumer. Should be matched with an AddConsumer call.
  38   //
  39   // Must be called on the I/O thread.
  40   void RemoveConsumer();
  41
  42   // Registers the given closure for calling when the user has interacted with
  43   // the device. This callback will only be issued once. Should only be called
  44   // while a consumer is active.
  45   void RegisterForUserGesture(const base::Closure& closure);
  46
  47   // Returns the shared memory handle of the gamepad data duplicated into the
  48   // given process.
  49   base::SharedMemoryHandle GetSharedMemoryHandleForProcess(
  50       base::ProcessHandle handle);
  51
  52   // Stop/join with the background thread in GamepadProvider |provider_|.
  53   void Terminate();
  54
  55  private:
  56   friend struct DefaultSingletonTraits<GamepadService>;
  57   friend class GamepadServiceTestConstructor;
  58
  59   GamepadService();
  60
  61   // Constructor for testing. This specifies the data fetcher to use for a
  62   // provider, bypassing the default platform one.
  63   GamepadService(scoped_ptr<GamepadDataFetcher> fetcher);
  64
  65   virtual ~GamepadService();
  66
  67   int num_readers_;
  68   scoped_ptr<GamepadProvider> provider_;
  69
  70   base::ThreadChecker thread_checker_;
  71
  72   DISALLOW_COPY_AND_ASSIGN(GamepadService);
  73 };
  74
  75 }  // namespace content
  76
  77 #endif  // CONTENT_BROWSER_GAMEPAD_GAMEPAD_SERVICE_H_