Generic Sensor API : Ambient Light Sensor API.

device/sensor/sensor_impl.cc

+// 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/sensor/sensor_impl.h"
+
+#include <utility>
+
+#include "base/bind.h"
+
+namespace device {
+
+// static
+void SensorImpl::Create(mojo::InterfaceRequest<AmbientLightSensor> request) {
+  new SensorImpl(std::move(request));
+}
+
+SensorImpl::SensorImpl(mojo::InterfaceRequest<AmbientLightSensor> request)
+    : binding_(this, std::move(request)), reading_to_report_(false) {
+  // NOTE: DidChange may be called before AddCallback returns. This is done to
+  // report current reading.
+  subscription_ = SensorService::GetInstance()->AddCallback(
+      base::Bind(&SensorImpl::DidChange, base::Unretained(this)));
+}
+
+SensorImpl::~SensorImpl() {}
+
+void SensorImpl::QueryNextReading(const SensorReadingCallback& callback) {
+  if (!callback_.is_null()) {
+    DVLOG(1) << "Overlapped call to QueryNextReading!";
+    delete this;
+    return;
+  }
+  callback_ = callback;
+
+  if (reading_to_report_)
+    ReportReading();
+}
+
+void SensorImpl::StartReading() {
+  // TODO(riju): To be implemented.
+}
+
+void SensorImpl::StopReading() {
+  // TODO(riju): To be implemented.
+}
+
+void SensorImpl::DidChange(const AmbientLightSensorReading& sensor_reading) {
+  reading_ = sensor_reading;
+  reading_to_report_ = true;
+
+  if (!callback_.is_null())
+    ReportReading();
+}
+
+void SensorImpl::ReportReading() {
+  callback_.Run(reading_.Clone());
+  callback_.reset();
+
+  reading_to_report_ = false;
+}
+
+}  // namespace device