public async Task <int> SetupSensor <T>(IBandSensor <T> sensor, int timeout, int value) where T : IBandSensorReading
{
var bandClient = await TestUtils.GetBandClientAsync();
var uc = sensor.GetCurrentUserConsent();
bool isConsented = false;
if (uc == UserConsent.NotSpecified)
{
isConsented = await sensor.RequestUserConsentAsync();
}
var tcs = new TaskCompletionSource <int>();
if (isConsented || uc == UserConsent.Granted)
{
sensor.ReadingChanged += (obj, ev) =>
{
// Set arbitrary result value
if (tcs.Task.Status != TaskStatus.RanToCompletion && tcs.Task.Status != TaskStatus.Faulted)
{
tcs.SetResult(5858);
}
};
await sensor.StartReadingsAsync();
}
try
{
await tcs.Task.TimeoutAfter(timeout);
}
finally
{
await sensor.StopReadingsAsync();
}
return(tcs.Task.Result);
}
private IObservable <BandSensorReadingEventArgs <T> > CreateObservableFromSensorEvent <T>(IBandSensor <T> manager) where T : IBandSensorReading
{
var obs = Observable.FromEvent <
EventHandler <BandSensorReadingEventArgs <T> >,
BandSensorReadingEventArgs <T> >
(
handler =>
{
EventHandler <BandSensorReadingEventArgs <T> > kpeHandler = (sender, e) => handler(e);
return(kpeHandler);
},
async x =>
{
try
{
manager.ReadingChanged += x;
await manager.StartReadingsAsync();
}
catch (Exception)
{
}
},
async x =>
{
try
{
manager.ReadingChanged -= x;
await manager.StopReadingsAsync();
}
catch (Exception)
{
throw;
}
}
);
return(obs);
}
private static IObservable <BandSensorReadingEventArgs <T> > CreateObservableFromSensorEvent <T>(
IBandSensor <T> bandSensor) where T : IBandSensorReading
{
var obs =
Observable.FromEvent <EventHandler <BandSensorReadingEventArgs <T> >, BandSensorReadingEventArgs <T> >(
handler =>
{
EventHandler <BandSensorReadingEventArgs <T> > kpeHandler = (sender, e) => handler(e);
return(kpeHandler);
},
async x =>
{
try
{
bandSensor.ReadingChanged += x;
await bandSensor.StartReadingsAsync();
}
catch (Exception ex)
{
Debug.WriteLine(ex);
}
},
async x =>
{
try
{
bandSensor.ReadingChanged -= x;
await bandSensor.StopReadingsAsync();
}
catch (Exception ex)
{
Debug.WriteLine(ex);
}
});
return(obs);
}
/// <summary>
/// Converts a Band sensor to an observable sequence.
/// </summary>
/// <typeparam name="T">Type of the Band sensor readings exposed by the observable sequence.</typeparam>
/// <param name="sensor">The Band sensor to obtain sensor readings from.</param>
/// <param name="startAndStopSensorReadings">If set to <c>true</c>, the lifecycle of the resulting observable sequence manages starting and stopping the readings from the sensor; if set to <c>false</c>, the caller is responsible to manage the lifetime of sensor readings manually.</param>
/// <returns>Observable sequence exposing the Band sensor readings.</returns>
public static IObservable <T> ToObservable <T>(this IBandSensor <T> sensor, bool startAndStopSensorReadings = true)
where T : IBandSensorReading
{
if (sensor == null)
{
throw new ArgumentNullException("sensor");
}
//
// Task to track an outstanding stop operation, if any. This is used to ensure
// sequential execution of start and stop requests.
//
var stopping = (Task)Task.FromResult(true);
//
// Observable wrapper around the ReadingChanged event for the Band sensor. It
// differs from FromEvent behavior in that it can optionally deal with lifecycle
// management to start and stop sensor readings.
//
var res = Observable.Create <T>(async(observer, ct) =>
{
EventHandler <BandSensorReadingEventArgs <T> > h = (o, e) =>
{
observer.OnNext(e.SensorReading);
};
sensor.ReadingChanged += h;
if (startAndStopSensorReadings)
{
//
// If we have an outstanding stop request, await it to avoid races.
//
await stopping.ConfigureAwait(false);
//
// Do the proper start.
//
try
{
await sensor.StartReadingsAsync(ct).ConfigureAwait(false);
}
catch (OperationCanceledException ex)
{
if (ex.CancellationToken != ct)
{
observer.OnError(ex);
}
return(Disposable.Empty);
}
}
return(Disposable.Create(async() =>
{
sensor.ReadingChanged -= h;
if (startAndStopSensorReadings)
{
//
// NOTE: Alternatively, we could just block on the task. Future releases
// of Rx may support IAsyncDisposable, which would provide a natural fit.
//
try
{
//
// If we have an outstanding stop request, await it to avoid races.
//
await stopping.ConfigureAwait(false);
//
// Initiate the stop operation and track it.
//
stopping = sensor.StopReadingsAsync();
await stopping.ConfigureAwait(false);
}
finally
{
//
// Unblock future awaits for the stop operation.
//
stopping = Task.FromResult(true);
}
}
}));
});
//
// Try to avoid attaching multiple event handlers and excessive start and stop
// requests to the underlying sensor. Even though it seems the Band SDK deals
// with this at a lower level, this allows fan-out to multiple subscriptions
// within the Rx layer.
//
res = res.Publish().RefCount();
return(res);
}