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 17 namespace content { 18 19 class 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. 24 class 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_motion_readers_; 61 int num_orientation_readers_; 62 bool is_shutdown_; 63 scoped_ptr<DataFetcherSharedMemory> data_fetcher_; 64 base::ThreadChecker thread_checker_; 65 66 DISALLOW_COPY_AND_ASSIGN(DeviceInertialSensorService); 67 }; 68 69 } // namespace content 70 71 #endif // CONTENT_BROWSER_DEVICE_SENSORS_DEVICE_INERTIAL_SENSOR_SERVICE_H_ 72