1// Copyright 2014 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_SENSORS_DEVICE_INERTIAL_SENSOR_SERVICE_H_
6#define CONTENT_BROWSER_DEVICE_SENSORS_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_sensors/inertial_sensor_consts.h"
15#include "content/common/content_export.h"
16
17namespace content {
18
19class DataFetcherSharedMemory;
20
21// Owns the data fetcher for Device Motion and Orientation and keeps track of
22// the number of consumers currently using the data. The data fetcher is stopped
23// when there are no consumers.
24class CONTENT_EXPORT DeviceInertialSensorService {
25 public:
26  // Returns the DeviceInertialSensorService singleton.
27  static DeviceInertialSensorService* GetInstance();
28
29  // Increments the number of users of the provider. The Provider is running
30  // when there's > 0 users, and is paused when the count drops to 0.
31  // Must be called on the I/O thread.
32  void AddConsumer(ConsumerType consumer_type);
33
34  // Removes a consumer. Should be matched with an AddConsumer call.
35  // Must be called on the I/O thread.
36  void RemoveConsumer(ConsumerType cosumer_type);
37
38  // Returns the shared memory handle of the device motion data duplicated
39  // into the given process.
40  base::SharedMemoryHandle GetSharedMemoryHandleForProcess(
41      ConsumerType consumer_type, base::ProcessHandle handle);
42
43  // Stop/join with the background polling thread in |provider_|.
44  void Shutdown();
45
46  // Injects a custom data fetcher for testing purposes. This class takes
47  // ownership of the injected object.
48  void SetDataFetcherForTesting(DataFetcherSharedMemory* test_data_fetcher);
49
50 private:
51  friend struct DefaultSingletonTraits<DeviceInertialSensorService>;
52
53  DeviceInertialSensorService();
54  virtual ~DeviceInertialSensorService();
55
56  bool ChangeNumberConsumers(ConsumerType consumer_type,
57      int delta);
58  int GetNumberConsumers(ConsumerType consumer_type) const;
59
60  int num_light_readers_;
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_SENSORS_DEVICE_INERTIAL_SENSOR_SERVICE_H_
73