[sensors] [win] Implement ambient light sensor for Windows platform

device/generic_sensor/platform_sensor_reader_win.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/generic_sensor/platform_sensor_reader_win.h"
+
+#include <Sensors.h>
+
+#include "base/callback.h"
+#include "base/time/time.h"
+#include "base/win/iunknown_impl.h"
+#include "device/generic_sensor/public/cpp/platform_sensor_configuration.h"
+#include "device/generic_sensor/public/cpp/sensor_reading.h"
+
+namespace device {
+
+// Init params for the PlatformSensorReaderWin.
+struct ReaderInitParams {
+  // ISensorDataReport::GetSensorValue is not const, therefore, report
+  // cannot be passed as const ref.
+  // ISensorDataReport& report - report that contains new sensor data.
+  // SensorReading& reading    - out parameter that must be populated.
+  // Returns HRESULT           - S_OK on success, otherwise error code.
+  using ReaderFunctor = base::Callback<HRESULT(ISensorDataReport& report,
+                                               SensorReading& reading)>;
+  SENSOR_TYPE_ID sensor_type_id;
+  mojom::ReportingMode reporting_mode;
+  ReaderFunctor reader_func;
+  unsigned long min_reporting_interval_ms = 0;
+};
+
+namespace {
+
+// Gets value from  the report for provided key.
+bool GetReadingValueForProperty(REFPROPERTYKEY key,
+                                ISensorDataReport& report,
+                                double* value) {
+  DCHECK(value);
+  PROPVARIANT variant_value = {};
+  if (SUCCEEDED(report.GetSensorValue(key, &variant_value))) {
+    if (variant_value.vt == VT_R8)
+      *value = variant_value.dblVal;
+    else if (variant_value.vt == VT_R4)
+      *value = variant_value.fltVal;
+    else
+      return false;
+    return true;
+  }
+
+  *value = 0;
+  return false;
+}
+
+// Creates ReaderInitParams params structure. To implement support for new
+// sensor types, new switch case should be added and appropriate fields must
+// be set:
+// sensor_type_id - GUID of the sensor supported by Windows.
+// reporting_mode - mode of reporting (ON_CHANGE | CONTINUOUS).
+// reader_func    - Functor that is responsible to populate SensorReading from
+//                  ISensorDataReport data.
+std::unique_ptr<ReaderInitParams> CreateReaderInitParamsForSensor(
+    mojom::SensorType type) {
+  auto params = std::make_unique<ReaderInitParams>();
+  switch (type) {
+    case mojom::SensorType::AMBIENT_LIGHT: {
+      params->sensor_type_id = SENSOR_TYPE_AMBIENT_LIGHT;
+      params->reporting_mode = mojom::ReportingMode::ON_CHANGE;
+      params->reader_func =
+          base::Bind([](ISensorDataReport& report, SensorReading& reading) {
+            double lux = 0.0;
+            if (!GetReadingValueForProperty(SENSOR_DATA_TYPE_LIGHT_LEVEL_LUX,
+                                            report, &lux)) {
+              return E_FAIL;
+            }
+            reading.values[0] = lux;
+            return S_OK;
+          });
+      return params;
+    }
+    default:
+      NOTIMPLEMENTED();
+      return nullptr;
+  }
+}
+}  // namespace

[Lei Zhang, 2016/10/29 05:10:42]

nit: blank line before

[shalamov, 2016/10/31 13:12:58]

Done.

+
+// Class that implements ISensorEvents and IUnknown interfaces and used
+// by ISensor interface to dispatch state and data change events.
+class EventListener : public ISensorEvents, public base::win::IUnknownImpl {
+ public:
+  explicit EventListener(PlatformSensorReaderWin* platform_sensor_reader)
+      : platform_sensor_reader_(platform_sensor_reader) {
+    DCHECK(platform_sensor_reader_);
+  }
+
+  // IUnknown interface
+  ULONG STDMETHODCALLTYPE AddRef() override { return IUnknownImpl::AddRef(); }
+  ULONG STDMETHODCALLTYPE Release() override { return IUnknownImpl::Release(); }
+
+  STDMETHODIMP QueryInterface(REFIID riid, void** ppv) override {
+    if (riid == __uuidof(ISensorEvents)) {
+      *ppv = static_cast<ISensorEvents*>(this);
+      AddRef();
+      return S_OK;
+    }
+    return IUnknownImpl::QueryInterface(riid, ppv);
+  }
+
+ protected:
+  ~EventListener() override = default;
+
+  // ISensorEvents interface
+  STDMETHODIMP OnEvent(ISensor*, REFGUID, IPortableDeviceValues*) override {
+    return S_OK;
+  }
+
+  STDMETHODIMP OnLeave(REFSENSOR_ID sensor_id) override {
+    // If event listener is active and sensor is disconnected, notify client
+    // about the error.
+    platform_sensor_reader_->SensorError();
+    platform_sensor_reader_->StopSensor();
+    return S_OK;
+  }
+
+  STDMETHODIMP OnStateChanged(ISensor* sensor, SensorState state) override {
+    if (sensor == nullptr)
+      return E_INVALIDARG;
+
+    if (state != SensorState::SENSOR_STATE_READY &&
+        state != SensorState::SENSOR_STATE_INITIALIZING) {
+      platform_sensor_reader_->SensorError();
+      platform_sensor_reader_->StopSensor();
+    }
+    return S_OK;
+  }
+
+  STDMETHODIMP OnDataUpdated(ISensor* sensor,
+                             ISensorDataReport* report) override {
+    if (sensor == nullptr || report == nullptr)
+      return E_INVALIDARG;
+
+    // To get precise timestamp, we need to get delta between timestamp
+    // provided in the report and current system time. Then the delta in
+    // milliseconds is substracted from current high resolution timestamp.
+    SYSTEMTIME report_time;
+    HRESULT hr = report->GetTimestamp(&report_time);
+    if (FAILED(hr))
+      return hr;
+
+    base::TimeTicks ticks_now = base::TimeTicks::Now();
+    base::Time time_now = base::Time::NowFromSystemTime();
+
+    base::Time::Exploded exploded;
+    exploded.year = report_time.wYear;
+    exploded.month = report_time.wMonth;
+    exploded.day_of_week = report_time.wDayOfWeek;
+    exploded.day_of_month = report_time.wDay;
+    exploded.hour = report_time.wHour;
+    exploded.minute = report_time.wMinute;
+    exploded.second = report_time.wSecond;
+    exploded.millisecond = report_time.wMilliseconds;
+
+    base::Time timestamp;
+    if (!base::Time::FromUTCExploded(exploded, &timestamp))
+      return E_FAIL;
+
+    base::TimeDelta delta = time_now - timestamp;
+
+    SensorReading reading;
+    reading.timestamp = ((ticks_now - delta) - base::TimeTicks()).InSecondsF();
+
+    // Discard update events that have non-monotonically increasing timestamp.
+    if (last_sensor_reading_.timestamp > reading.timestamp)
+      return E_FAIL;
+
+    hr = platform_sensor_reader_->SensorReadingChanged(*report, reading);
+    if (SUCCEEDED(hr))
+      last_sensor_reading_ = reading;
+    return hr;
+  }
+
+ private:
+  PlatformSensorReaderWin* platform_sensor_reader_;

[Lei Zhang, 2016/10/29 05:10:42]

You can do: PlatformSensorReaderWin* const platform_sensor_reader_;

Which combined with the DCHECK() in the ctor, means readers of this code will
know this pointer is never a nullptr.

[shalamov, 2016/10/31 13:12:58]

Done.

+  SensorReading last_sensor_reading_;
+
+  DISALLOW_COPY_AND_ASSIGN(EventListener);
+};
+
+// static
+std::unique_ptr<PlatformSensorReaderWin> PlatformSensorReaderWin::Create(
+    mojom::SensorType type,
+    base::win::ScopedComPtr<ISensorManager> sensor_manager) {
+  DCHECK(sensor_manager);
+
+  auto params = CreateReaderInitParamsForSensor(type);
+  if (!params)
+    return nullptr;
+
+  auto sensor = GetSensorForType(params->sensor_type_id, sensor_manager);
+  if (!sensor)
+    return nullptr;
+
+  PROPVARIANT variant = {};
+  if (SUCCEEDED(
+          sensor->GetProperty(SENSOR_PROPERTY_MIN_REPORT_INTERVAL, &variant))) {
+    if (variant.vt == VT_UI4)
+      params->min_reporting_interval_ms = variant.ulVal;
+  }
+
+  GUID interests[] = {SENSOR_EVENT_STATE_CHANGED, SENSOR_EVENT_DATA_UPDATED};
+  HRESULT hr = sensor->SetEventInterest(interests, arraysize(interests));
+  if (FAILED(hr))
+    return nullptr;
+
+  return base::WrapUnique(

[Lei Zhang, 2016/10/29 05:10:42]

Can this be base::MakeUnique()?

[shalamov, 2016/10/31 13:12:58]

Constructor is private, can't use base::MakeUnique here.

+      new PlatformSensorReaderWin(sensor, std::move(params)));
+}
+
+// static
+base::win::ScopedComPtr<ISensor> PlatformSensorReaderWin::GetSensorForType(
+    REFSENSOR_TYPE_ID sensor_type,
+    base::win::ScopedComPtr<ISensorManager> sensor_manager) {
+  base::win::ScopedComPtr<ISensor> sensor;
+  base::win::ScopedComPtr<ISensorCollection> sensor_collection;
+  HRESULT hr = sensor_manager->GetSensorsByType(sensor_type,
+                                                sensor_collection.Receive());
+  if (FAILED(hr) || !sensor_collection)
+    return sensor;
+
+  ULONG count = 0;
+  hr = sensor_collection->GetCount(&count);
+  if (FAILED(hr) || count == 0)

[Lei Zhang, 2016/10/29 05:10:42]

Since you return |sensor| either way here:

if (SUCCEEDED(hr) && count > 0)
  sensor_collection->GetAt(0, sensor.Receive());
return sensor;

[shalamov, 2016/10/31 13:12:57]

Done.

+    return sensor;
+
+  sensor_collection->GetAt(0, sensor.Receive());
+  return sensor;
+}
+
+PlatformSensorReaderWin::PlatformSensorReaderWin(
+    base::win::ScopedComPtr<ISensor> sensor,
+    std::unique_ptr<ReaderInitParams> params)
+    : init_params_(std::move(params)),
+      task_runner_(base::ThreadTaskRunnerHandle::Get()),
+      sensor_active_(false),
+      client_(nullptr),
+      sensor_(sensor),
+      event_listener_(new EventListener(this)) {
+  DCHECK(init_params_);
+  DCHECK(!init_params_->reader_func.is_null());
+  DCHECK(sensor_);
+}
+
+void PlatformSensorReaderWin::SetClient(Client* client) {
+  base::AutoLock autolock(lock_);
+  // Can be null.
+  client_ = client;
+}
+
+void PlatformSensorReaderWin::StopSensor() {
+  base::AutoLock autolock(lock_);
+  if (sensor_active_) {
+    sensor_->SetEventSink(nullptr);
+    sensor_active_ = false;
+  }
+}
+
+PlatformSensorReaderWin::~PlatformSensorReaderWin() {
+  DCHECK(task_runner_->BelongsToCurrentThread());
+}
+
+bool PlatformSensorReaderWin::StartSensor(
+    const PlatformSensorConfiguration& configuration) {
+  base::AutoLock autolock(lock_);
+
+  if (!SetReportingInterval(configuration))
+    return false;
+
+  // Set event listener.
+  if (!sensor_active_) {
+    base::win::ScopedComPtr<ISensorEvents> sensor_events;
+    HRESULT hr = event_listener_->QueryInterface(__uuidof(ISensorEvents),
+                                                 sensor_events.ReceiveVoid());
+
+    if (FAILED(hr) || !sensor_events)
+      return false;
+
+    if (FAILED(sensor_->SetEventSink(sensor_events.get())))
+      return false;
+
+    sensor_active_ = true;
+  }
+
+  return true;
+}
+
+bool PlatformSensorReaderWin::SetReportingInterval(
+    const PlatformSensorConfiguration& configuration) {
+  base::win::ScopedComPtr<IPortableDeviceValues> props;
+  if (SUCCEEDED(props.CreateInstance(CLSID_PortableDeviceValues))) {
+    unsigned interval =
+        (1 / configuration.frequency()) * base::Time::kMillisecondsPerSecond;
+    if (SUCCEEDED(props->SetUnsignedIntegerValue(
+            SENSOR_PROPERTY_CURRENT_REPORT_INTERVAL, interval))) {
+      base::win::ScopedComPtr<IPortableDeviceValues> return_props;
+      sensor_->SetProperties(props.get(), return_props.Receive());
+      return true;
+    }
+  }
+  return false;
+}
+
+HRESULT PlatformSensorReaderWin::SensorReadingChanged(
+    ISensorDataReport& report,
+    SensorReading& reading) const {
+  if (!client_)
+    return E_FAIL;
+
+  HRESULT hr = init_params_->reader_func.Run(report, reading);
+  if (SUCCEEDED(hr))
+    client_->OnReadingUpdated(reading);
+  return hr;
+}
+
+void PlatformSensorReaderWin::SensorError() {
+  if (client_)
+    client_->OnSensorError();
+}
+
+unsigned long PlatformSensorReaderWin::GetMinimalReportingIntervalMs() const {
+  return init_params_->min_reporting_interval_ms;
+}
+
+mojom::ReportingMode PlatformSensorReaderWin::GetReportingMode() const {
+  return init_params_->reporting_mode;
+}
+
+}  // namespace device