91 lines
2.9 KiB
C#
91 lines
2.9 KiB
C#
// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved. See License.txt in the project root for license information.
|
|
|
|
#if HAS_AWAIT
|
|
using System;
|
|
using System.Threading;
|
|
using System.Reactive.Disposables;
|
|
using System.Reactive.Subjects;
|
|
|
|
namespace System.Reactive.Linq
|
|
{
|
|
internal partial class QueryLanguage
|
|
{
|
|
public virtual AsyncSubject<TSource> GetAwaiter<TSource>(IObservable<TSource> source)
|
|
{
|
|
return RunAsync<TSource>(source, CancellationToken.None);
|
|
}
|
|
|
|
public virtual AsyncSubject<TSource> GetAwaiter<TSource>(IConnectableObservable<TSource> source)
|
|
{
|
|
return RunAsync<TSource>(source, CancellationToken.None);
|
|
}
|
|
|
|
public virtual AsyncSubject<TSource> RunAsync<TSource>(IObservable<TSource> source, CancellationToken cancellationToken)
|
|
{
|
|
var s = new AsyncSubject<TSource>();
|
|
|
|
if (cancellationToken.IsCancellationRequested)
|
|
{
|
|
return Cancel(s);
|
|
}
|
|
|
|
var d = source.SubscribeSafe(s);
|
|
|
|
if (cancellationToken.CanBeCanceled)
|
|
{
|
|
RegisterCancelation(s, d, cancellationToken);
|
|
}
|
|
|
|
return s;
|
|
}
|
|
|
|
public virtual AsyncSubject<TSource> RunAsync<TSource>(IConnectableObservable<TSource> source, CancellationToken cancellationToken)
|
|
{
|
|
var s = new AsyncSubject<TSource>();
|
|
|
|
if (cancellationToken.IsCancellationRequested)
|
|
{
|
|
return Cancel(s);
|
|
}
|
|
|
|
var d = source.SubscribeSafe(s);
|
|
var c = source.Connect();
|
|
|
|
if (cancellationToken.CanBeCanceled)
|
|
{
|
|
RegisterCancelation(s, new CompositeDisposable(d, c), cancellationToken);
|
|
}
|
|
|
|
return s;
|
|
}
|
|
|
|
private static AsyncSubject<T> Cancel<T>(AsyncSubject<T> subject)
|
|
{
|
|
subject.OnError(new OperationCanceledException());
|
|
return subject;
|
|
}
|
|
|
|
private static void RegisterCancelation<T>(AsyncSubject<T> subject, IDisposable subscription, CancellationToken token)
|
|
{
|
|
//
|
|
// Separate method used to avoid heap allocation of closure when no cancellation is needed,
|
|
// e.g. when CancellationToken.None is provided to the RunAsync overloads.
|
|
//
|
|
|
|
var ctr = token.Register(() =>
|
|
{
|
|
subscription.Dispose();
|
|
Cancel(subject);
|
|
});
|
|
|
|
//
|
|
// No null-check for ctr is needed:
|
|
//
|
|
// - CancellationTokenRegistration is a struct
|
|
// - Registration will succeed 99% of the time, no warranting an attempt to avoid spurious Subscribe calls
|
|
//
|
|
subject.Subscribe(Stubs<T>.Ignore, _ => ctr.Dispose(), ctr.Dispose);
|
|
}
|
|
}
|
|
}
|
|
#endif |