content/browser/device_orientation/device_inertial_sensor_service.h

   1 // Copyright 2013 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_DEVICE_ORIENTATION_DEVICE_INERTIAL_SENSOR_SERVICE_H_
   6 #define CONTENT_BROWSER_DEVICE_ORIENTATION_DEVICE_INERTIAL_SENSOR_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/browser/device_orientation/inertial_sensor_consts.h"
  15 #include "content/common/content_export.h"
  16
  17 namespace content {
  18
  19 class DataFetcherSharedMemory;
  20 class RenderProcessHost;
  21
  22 // Owns the DeviceMotionProvider (the background polling thread) and keeps
  23 // track of the number of consumers currently using the data (and pausing
  24 // the provider when not in use).
  25 class CONTENT_EXPORT DeviceInertialSensorService {
  26  public:
  27   // Returns the DeviceInertialSensorService singleton.
  28   static DeviceInertialSensorService* GetInstance();
  29
  30   // Increments the number of users of the provider. The Provider is running
  31   // when there's > 0 users, and is paused when the count drops to 0.
  32   // Must be called on the I/O thread.
  33   void AddConsumer(ConsumerType consumer_type);
  34
  35   // Removes a consumer. Should be matched with an AddConsumer call.
  36   // Must be called on the I/O thread.
  37   void RemoveConsumer(ConsumerType cosumer_type);
  38
  39   // Returns the shared memory handle of the device motion data duplicated
  40   // into the given process.
  41   base::SharedMemoryHandle GetSharedMemoryHandleForProcess(
  42       ConsumerType consumer_type, base::ProcessHandle handle);
  43
  44   // Stop/join with the background polling thread in |provider_|.
  45   void Shutdown();
  46
  47   // Injects a custom data fetcher for testing purposes. This class takes
  48   // ownership of the injected object.
  49   void SetDataFetcherForTests(DataFetcherSharedMemory* test_data_fetcher);
  50
  51  private:
  52   friend struct DefaultSingletonTraits<DeviceInertialSensorService>;
  53
  54   DeviceInertialSensorService();
  55   virtual ~DeviceInertialSensorService();
  56
  57   bool ChangeNumberConsumers(ConsumerType consumer_type,
  58       int delta);
  59   int GetNumberConsumers(ConsumerType consumer_type) const;
  60
  61   int num_motion_readers_;
  62   int num_orientation_readers_;
  63   bool is_shutdown_;
  64   scoped_ptr<DataFetcherSharedMemory> data_fetcher_;
  65   base::ThreadChecker thread_checker_;
  66
  67   DISALLOW_COPY_AND_ASSIGN(DeviceInertialSensorService);
  68 };
  69
  70 }  // namespace content
  71
  72 #endif  // CONTENT_BROWSER_DEVICE_ORIENTATION_DEVICE_INERTIAL_SENSOR_SERVICE_H_