gecko/hal/windows/WindowsSensor.cpp

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this file,
 * You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "Hal.h"

#include <sensorsapi.h>
#include <sensors.h>
#include <portabledevicetypes.h>

#define MEAN_GRAVITY 9.80665
#define DEFAULT_SENSOR_POLL 100

using namespace mozilla::hal;

namespace mozilla {
namespace hal_impl {

static nsRefPtr<ISensor> sAccelerometer;

class SensorEvent final : public ISensorEvents {
public:
  SensorEvent() : mCount(0) {
  }

  // IUnknown interface

  STDMETHODIMP_(ULONG) AddRef() {
    return InterlockedIncrement(&mCount);
  }

  STDMETHODIMP_(ULONG) Release() {
    ULONG count = InterlockedDecrement(&mCount);
    if (!count) {
      delete this;
      return 0;
    }
    return count;
  }

  STDMETHODIMP QueryInterface(REFIID iid, void** ppv) {
    if (iid == IID_IUnknown) {
      *ppv = static_cast<IUnknown*>(this);
    } else if (iid == IID_ISensorEvents) {
      *ppv = static_cast<ISensorEvents*>(this);
    } else {
      return E_NOINTERFACE;
    }
    AddRef();
    return S_OK;
  }

  // ISensorEvents interface

  STDMETHODIMP OnEvent(ISensor *aSensor, REFGUID aId, IPortableDeviceValues *aData) {
    return S_OK;
  }

  STDMETHODIMP OnLeave(REFSENSOR_ID aId) {
    return S_OK;
  }

  STDMETHODIMP OnStateChanged(ISensor *aSensor, SensorState state) {
    return S_OK;
  }

  STDMETHODIMP OnDataUpdated(ISensor *aSensor, ISensorDataReport *aReport) {
    PROPVARIANT v;
    HRESULT hr;
    InfallibleTArray<float> values;

    // X-axis acceleration in g's
    hr = aReport->GetSensorValue(SENSOR_DATA_TYPE_ACCELERATION_X_G, &v);
    if (FAILED(hr)) {
      return hr;
    }
    values.AppendElement(float(-v.dblVal * MEAN_GRAVITY));

    // Y-axis acceleration in g's
    hr = aReport->GetSensorValue(SENSOR_DATA_TYPE_ACCELERATION_Y_G, &v);
    if (FAILED(hr)) {
      return hr;
    }
    values.AppendElement(float(-v.dblVal * MEAN_GRAVITY));

    // Z-axis acceleration in g's
    hr = aReport->GetSensorValue(SENSOR_DATA_TYPE_ACCELERATION_Z_G, &v);
    if (FAILED(hr)) {
      return hr;
    }
    values.AppendElement(float(-v.dblVal * MEAN_GRAVITY));

    hal::SensorData sdata(hal::SENSOR_ACCELERATION,
                          PR_Now(),
                          values,
                          hal::SENSOR_ACCURACY_UNKNOWN);
    hal::NotifySensorChange(sdata);

    return S_OK;
  }

private:
  ULONG mCount;
};

void
EnableSensorNotifications(SensorType aSensor)
{
  if (aSensor != SENSOR_ACCELERATION) {
    return;
  }

  if (sAccelerometer) {
    return;
  }

  nsRefPtr<ISensorManager> manager;
  if (FAILED(CoCreateInstance(CLSID_SensorManager, nullptr,
                              CLSCTX_INPROC_SERVER,
                              IID_ISensorManager, 
                              getter_AddRefs(manager)))) {
    return;
  }

  // accelerometer event

  nsRefPtr<ISensorCollection> collection;
  if (FAILED(manager->GetSensorsByType(SENSOR_TYPE_ACCELEROMETER_3D,
                                       getter_AddRefs(collection)))) {
    return;
  }

  ULONG count = 0;
  collection->GetCount(&count);
  if (!count) {
    return;
  }

  nsRefPtr<ISensor> sensor;
  collection->GetAt(0, getter_AddRefs(sensor));
  if (!sensor) {
    return;
  }

  // Set report interval to 100ms if possible. 
  // Default value depends on drivers.
  nsRefPtr<IPortableDeviceValues> values;
  if (SUCCEEDED(CoCreateInstance(CLSID_PortableDeviceValues, nullptr,
                                 CLSCTX_INPROC_SERVER,
                                 IID_IPortableDeviceValues,
                                 getter_AddRefs(values)))) {
    if (SUCCEEDED(values->SetUnsignedIntegerValue(
                    SENSOR_PROPERTY_CURRENT_REPORT_INTERVAL,
                    DEFAULT_SENSOR_POLL))) {
      nsRefPtr<IPortableDeviceValues> returns;
      sensor->SetProperties(values, getter_AddRefs(returns));
    }
  }

  nsRefPtr<SensorEvent> event = new SensorEvent();
  nsRefPtr<ISensorEvents> sensorEvents;
  if (FAILED(event->QueryInterface(IID_ISensorEvents,
                                   getter_AddRefs(sensorEvents)))) {
    return;
  }

  if (FAILED(sensor->SetEventSink(sensorEvents))) {
    return;
  }

  sAccelerometer = sensor;
}

void
DisableSensorNotifications(SensorType aSensor)
{
  if (aSensor == SENSOR_ACCELERATION && sAccelerometer) {
    sAccelerometer->SetEventSink(nullptr);
    sAccelerometer = nullptr;
  }
}

} // hal_impl
} // mozilla