[sensors] Introduce Generic Sensor API interfaces

device/generic_sensor/platform_sensor_provider.h

+// Copyright 2016 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_SENSORS_PLATFORM_SENSOR_PROVIDER_H_

[timvolodine, 2016/08/18 22:52:14]

-> DEVICE_GENERIC_SENSOR_PLATFORM..

[Mikhail, 2016/08/19 09:29:55]

Done.

+#define DEVICE_SENSORS_PLATFORM_SENSOR_PROVIDER_H_
+
+#include "base/macros.h"
+
+#include "base/threading/non_thread_safe.h"
+#include "device/generic_sensor/platform_sensor.h"
+
+namespace device {
+
+// Base class that defines factory methods for PlatformSensor creation.
+class PlatformSensorProvider : public base::NonThreadSafe {
+ public:
+  static PlatformSensorProvider* Create(uint64_t shared_buffer_size);

[timvolodine, 2016/08/18 22:52:14]

is this a singleton? then seems better to have a GetInstance() method with
base::Singleton semantics (without parameter instead using
kSharedBufferSizeInBytes directly)

[Mikhail, 2016/08/19 09:29:55]

Done.

+
+  // Creates new instance of PlatformSensor.
+  scoped_refptr<PlatformSensor> CreateSensor(mojom::SensorType type,
+                                             uint64_t size,
+                                             uint64_t offset);
+
+  // Gets previously created instance of PlatformSensor by sensor type |type|.
+  scoped_refptr<PlatformSensor> GetSensor(mojom::SensorType type);
+
+  // Shared buffer getters.
+  mojo::ScopedSharedBufferHandle CloneSharedBufferHandle();
+
+ protected:
+  explicit PlatformSensorProvider(uint64_t shared_buffer_size);
+  virtual ~PlatformSensorProvider();
+
+  // Method that must be implemented by platform specific classes.
+  virtual scoped_refptr<PlatformSensor> CreateSensorInternal(
+      mojom::SensorType type,
+      mojo::ScopedSharedBufferMapping mapping,
+      uint64_t buffer_size) = 0;
+
+ private:
+  friend class PlatformSensor;  // To call RemoveSensor();
+
+  bool CreateSharedBufferIfNeeded();
+  void RemoveSensor(mojom::SensorType type);
+
+ private:
+  std::map<mojom::SensorType, PlatformSensor*> sensor_map_;
+  mojo::ScopedSharedBufferHandle shared_buffer_handle_;
+  uint64_t shared_buffer_size_;
+  DISALLOW_COPY_AND_ASSIGN(PlatformSensorProvider);
+};
+
+}  // namespace device
+
+#endif  // DEVICE_SENSORS_PLATFORM_SENSOR_PROVIDER_H_