Move //content/browser/device_sensor/ into device/sensors

content/browser/device_sensors/data_fetcher_shared_memory_base.h

-// Copyright 2014 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 CONTENT_BROWSER_DEVICE_SENSORS_DATA_FETCHER_SHARED_MEMORY_BASE_H_
-#define CONTENT_BROWSER_DEVICE_SENSORS_DATA_FETCHER_SHARED_MEMORY_BASE_H_
-
-#include <map>
-#include <memory>
-
-#include "base/macros.h"
-#include "base/memory/shared_memory.h"
-#include "base/message_loop/message_loop.h"
-#include "content/browser/device_sensors/device_sensors_consts.h"
-#include "content/common/content_export.h"
-#include "mojo/public/cpp/system/buffer.h"
-
-namespace content {
-
-// Sensor data fetchers should derive from this base class and implement
-// the abstract Start() and Stop() methods.
-// If the fetcher requires polling it should also implement IsPolling()
-// to return true and the Fetch() method which will be called from the
-// polling thread to fetch data at regular intervals.
-class CONTENT_EXPORT DataFetcherSharedMemoryBase {
- public:
-  // Starts updating the shared memory buffer with sensor data at
-  // regular intervals. Returns true if the relevant sensors could
-  // be successfully activated.
-  bool StartFetchingDeviceData(ConsumerType consumer_type);
-
-  // Stops updating the shared memory buffer. Returns true if the
-  // relevant sensors could be successfully deactivated.
-  bool StopFetchingDeviceData(ConsumerType consumer_type);
-
-  // Should be called before destruction to make sure all active
-  // sensors are unregistered.
-  virtual void Shutdown();
-
-  // Returns the shared memory handle of the device sensor data. This method
-  // should only be called after a call to StartFetchingDeviceData method with
-  // corresponding |consumer_type| parameter.
-  mojo::ScopedSharedBufferHandle GetSharedMemoryHandle(
-      ConsumerType consumer_type);
-
-  enum FetcherType {
-    // Fetcher runs on the same thread as its creator.
-    FETCHER_TYPE_DEFAULT,
-    // Fetcher runs on a separate thread calling |Fetch()| at regular intervals.
-    FETCHER_TYPE_POLLING_CALLBACK,
-    // Fetcher runs on a separate thread, but no callbacks are executed.
-    FETCHER_TYPE_SEPARATE_THREAD
-  };
-
- protected:
-  class PollingThread;
-
-  DataFetcherSharedMemoryBase();
-  virtual ~DataFetcherSharedMemoryBase();
-
-  // Returns the message loop of the polling thread.
-  // Returns NULL if there is no polling thread.
-  base::MessageLoop* GetPollingMessageLoop() const;
-
-  // If IsPolling() is true this method is called from the |polling_thread_|
-  // at regular intervals.
-  virtual void Fetch(unsigned consumer_bitmask);
-
-  // Returns the type of thread this fetcher runs on.
-  virtual FetcherType GetType() const;
-
-  // Returns the sensor sampling interval. In particular if this fetcher
-  // GetType() == FETCHER_TYPE_POLLING_CALLBACK the interval between
-  // successive calls to Fetch().
-  virtual base::TimeDelta GetInterval() const;
-
-  // Start() method should call InitSharedMemoryBuffer() to get the shared
-  // memory pointer. If IsPolling() is true both Start() and Stop() methods
-  // are called from the |polling_thread_|.
-  virtual bool Start(ConsumerType consumer_type, void* buffer) = 0;
-  virtual bool Stop(ConsumerType consumer_type) = 0;
-
-  bool IsPollingTimerRunningForTesting() const;
-
- private:
-  bool InitAndStartPollingThreadIfNecessary();
-  void* GetSharedMemoryBuffer(ConsumerType consumer_type);
-
-  unsigned started_consumers_;
-
-  std::unique_ptr<PollingThread> polling_thread_;
-
-  using SharedMemoryMap = std::map<ConsumerType,
-                                   std::pair<mojo::ScopedSharedBufferHandle,
-                                             mojo::ScopedSharedBufferMapping>>;
-  SharedMemoryMap shared_memory_map_;
-
-  DISALLOW_COPY_AND_ASSIGN(DataFetcherSharedMemoryBase);
-};
-
-}  // namespace content
-
-#endif  // CONTENT_BROWSER_DEVICE_SENSORS_DATA_FETCHER_SHARED_MEMORY_BASE_H_