Revert of Move //device/generic_sensor to be part of the internal implementation of the Device Service.

device/generic_sensor/platform_sensor_provider_linux.cc

Index: device/generic_sensor/platform_sensor_provider_linux.cc
diff --git a/device/generic_sensor/platform_sensor_provider_linux.cc b/device/generic_sensor/platform_sensor_provider_linux.cc
new file mode 100644
index 0000000000000000000000000000000000000000..4db2a4c97e47fa21ff422162654a3a8e2807505e
--- /dev/null
+++ b/device/generic_sensor/platform_sensor_provider_linux.cc
@@ -0,0 +1,214 @@
+// 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.
+
+#include "device/generic_sensor/platform_sensor_provider_linux.h"
+
+#include "base/memory/singleton.h"
+#include "base/message_loop/message_loop.h"
+#include "base/task_runner_util.h"
+#include "base/threading/thread.h"
+#include "device/generic_sensor/linux/sensor_data_linux.h"
+#include "device/generic_sensor/platform_sensor_linux.h"
+#include "device/generic_sensor/platform_sensor_reader_linux.h"
+
+namespace device {
+
+// static
+PlatformSensorProviderLinux* PlatformSensorProviderLinux::GetInstance() {
+  return base::Singleton<
+      PlatformSensorProviderLinux,
+      base::LeakySingletonTraits<PlatformSensorProviderLinux>>::get();
+}
+
+PlatformSensorProviderLinux::PlatformSensorProviderLinux()
+    : sensor_nodes_enumerated_(false),
+      sensor_nodes_enumeration_started_(false),
+      sensor_device_manager_(nullptr) {}
+
+PlatformSensorProviderLinux::~PlatformSensorProviderLinux() {
+  DCHECK(!sensor_device_manager_);
+}
+
+void PlatformSensorProviderLinux::CreateSensorInternal(
+    mojom::SensorType type,
+    mojo::ScopedSharedBufferMapping mapping,
+    const CreateSensorCallback& callback) {
+  if (!sensor_device_manager_)
+    sensor_device_manager_.reset(new SensorDeviceManager());
+
+  if (!sensor_nodes_enumerated_) {
+    if (!sensor_nodes_enumeration_started_) {
+      sensor_nodes_enumeration_started_ = file_task_runner_->PostTask(
+          FROM_HERE,
+          base::Bind(&SensorDeviceManager::Start,
+                     base::Unretained(sensor_device_manager_.get()), this));
+    }
+    return;
+  }
+
+  SensorInfoLinux* sensor_device = GetSensorDevice(type);
+  if (!sensor_device) {
+    // If there are no sensors, stop polling thread.
+    if (!HasSensors())
+      AllSensorsRemoved();
+    callback.Run(nullptr);
+    return;
+  }
+  SensorDeviceFound(type, std::move(mapping), callback, sensor_device);
+}
+
+void PlatformSensorProviderLinux::SensorDeviceFound(
+    mojom::SensorType type,
+    mojo::ScopedSharedBufferMapping mapping,
+    const PlatformSensorProviderBase::CreateSensorCallback& callback,
+    const SensorInfoLinux* sensor_device) {
+  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
+  DCHECK(sensor_device);
+
+  if (!StartPollingThread()) {
+    callback.Run(nullptr);
+    return;
+  }
+
+  scoped_refptr<PlatformSensorLinux> sensor =
+      new PlatformSensorLinux(type, std::move(mapping), this, sensor_device,
+                              polling_thread_->task_runner());
+  callback.Run(sensor);
+}
+
+void PlatformSensorProviderLinux::SetFileTaskRunner(
+    scoped_refptr<base::SingleThreadTaskRunner> file_task_runner) {
+  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
+  if (!file_task_runner_)
+    file_task_runner_ = file_task_runner;
+}
+
+void PlatformSensorProviderLinux::AllSensorsRemoved() {
+  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
+  DCHECK(file_task_runner_);
+  Shutdown();
+  // When there are no sensors left, the polling thread must be stopped.
+  // Stop() can only be called on a different thread that allows I/O.
+  // Thus, browser's file thread is used for this purpose.
+  file_task_runner_->PostTask(
+      FROM_HERE, base::Bind(&PlatformSensorProviderLinux::StopPollingThread,
+                            base::Unretained(this)));
+}
+
+bool PlatformSensorProviderLinux::StartPollingThread() {
+  if (!polling_thread_)
+    polling_thread_.reset(new base::Thread("Sensor polling thread"));
+
+  if (!polling_thread_->IsRunning()) {
+    return polling_thread_->StartWithOptions(
+        base::Thread::Options(base::MessageLoop::TYPE_IO, 0));
+  }
+  return true;
+}
+
+void PlatformSensorProviderLinux::StopPollingThread() {
+  DCHECK(file_task_runner_);
+  DCHECK(file_task_runner_->BelongsToCurrentThread());
+  if (polling_thread_ && polling_thread_->IsRunning())
+    polling_thread_->Stop();
+}
+
+void PlatformSensorProviderLinux::Shutdown() {
+  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
+  const bool did_post_task = file_task_runner_->DeleteSoon(
+      FROM_HERE, sensor_device_manager_.release());
+  DCHECK(did_post_task);
+  sensor_nodes_enumerated_ = false;
+  sensor_nodes_enumeration_started_ = false;
+  sensor_devices_by_type_.clear();
+}
+
+SensorInfoLinux* PlatformSensorProviderLinux::GetSensorDevice(
+    mojom::SensorType type) {
+  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
+  auto sensor = sensor_devices_by_type_.find(type);
+  if (sensor == sensor_devices_by_type_.end())
+    return nullptr;
+  return sensor->second.get();
+}
+
+void PlatformSensorProviderLinux::GetAllSensorDevices() {
+  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
+  // TODO(maksims): implement this method once we have discovery API.
+  NOTIMPLEMENTED();
+}
+
+void PlatformSensorProviderLinux::SetSensorDeviceManagerForTesting(
+    std::unique_ptr<SensorDeviceManager> sensor_device_manager) {
+  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
+  Shutdown();
+  sensor_device_manager_ = std::move(sensor_device_manager);
+}
+
+void PlatformSensorProviderLinux::SetFileTaskRunnerForTesting(
+    scoped_refptr<base::SingleThreadTaskRunner> task_runner) {
+  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
+  file_task_runner_ = std::move(task_runner);
+}
+
+void PlatformSensorProviderLinux::ProcessStoredRequests() {
+  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
+  std::vector<mojom::SensorType> request_types = GetPendingRequestTypes();
+  if (request_types.empty())
+    return;
+
+  for (auto const& type : request_types) {
+    SensorInfoLinux* device = nullptr;
+    auto device_entry = sensor_devices_by_type_.find(type);
+    if (device_entry != sensor_devices_by_type_.end())
+      device = device_entry->second.get();
+    CreateSensorAndNotify(type, device);
+  }
+}
+
+void PlatformSensorProviderLinux::CreateSensorAndNotify(
+    mojom::SensorType type,
+    SensorInfoLinux* sensor_device) {
+  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
+  scoped_refptr<PlatformSensorLinux> sensor;
+  mojo::ScopedSharedBufferMapping mapping = MapSharedBufferForType(type);
+  if (sensor_device && mapping && StartPollingThread()) {
+    sensor =
+        new PlatformSensorLinux(type, std::move(mapping), this, sensor_device,
+                                polling_thread_->task_runner());
+  }
+  NotifySensorCreated(type, sensor);
+}
+
+void PlatformSensorProviderLinux::OnSensorNodesEnumerated() {
+  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
+  DCHECK(!sensor_nodes_enumerated_);
+  sensor_nodes_enumerated_ = true;
+  ProcessStoredRequests();
+}
+
+void PlatformSensorProviderLinux::OnDeviceAdded(
+    mojom::SensorType type,
+    std::unique_ptr<SensorInfoLinux> sensor_device) {
+  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
+  // At the moment, we support only one device per type.
+  if (base::ContainsKey(sensor_devices_by_type_, type)) {
+    DVLOG(1) << "Sensor ignored. Type " << type
+             << ". Node: " << sensor_device->device_node;
+    return;
+  }
+  sensor_devices_by_type_[type] = std::move(sensor_device);
+}
+
+void PlatformSensorProviderLinux::OnDeviceRemoved(
+    mojom::SensorType type,
+    const std::string& device_node) {
+  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
+  auto it = sensor_devices_by_type_.find(type);
+  if (it != sensor_devices_by_type_.end() &&
+      it->second->device_node == device_node)
+    sensor_devices_by_type_.erase(it);
+}
+
+}  // namespace device