/
QueryLanguage.Blocking.cs
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/
QueryLanguage.Blocking.cs
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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the Apache 2.0 License.
// See the LICENSE file in the project root for more information.
using System.Collections.Generic;
using System.Threading;
namespace System.Reactive.Linq
{
using ObservableImpl;
internal partial class QueryLanguage
{
#region - Chunkify -
public virtual IEnumerable<IList<TSource>> Chunkify<TSource>(IObservable<TSource> source)
{
return source.Collect<TSource, IList<TSource>>(() => new List<TSource>(), (lst, x) => { lst.Add(x); return lst; }, _ => new List<TSource>());
}
#endregion
#region + Collect +
public virtual IEnumerable<TResult> Collect<TSource, TResult>(IObservable<TSource> source, Func<TResult> newCollector, Func<TResult, TSource, TResult> merge)
{
return Collect_(source, newCollector, merge, _ => newCollector());
}
public virtual IEnumerable<TResult> Collect<TSource, TResult>(IObservable<TSource> source, Func<TResult> getInitialCollector, Func<TResult, TSource, TResult> merge, Func<TResult, TResult> getNewCollector)
{
return Collect_(source, getInitialCollector, merge, getNewCollector);
}
private static IEnumerable<TResult> Collect_<TSource, TResult>(IObservable<TSource> source, Func<TResult> getInitialCollector, Func<TResult, TSource, TResult> merge, Func<TResult, TResult> getNewCollector)
{
return new Collect<TSource, TResult>(source, getInitialCollector, merge, getNewCollector);
}
#endregion
#region First
public virtual TSource First<TSource>(IObservable<TSource> source)
{
return FirstOrDefaultInternal(source, true);
}
public virtual TSource First<TSource>(IObservable<TSource> source, Func<TSource, bool> predicate)
{
return First(Where(source, predicate));
}
#endregion
#region FirstOrDefault
public virtual TSource FirstOrDefault<TSource>(IObservable<TSource> source)
{
return FirstOrDefaultInternal(source, false);
}
public virtual TSource FirstOrDefault<TSource>(IObservable<TSource> source, Func<TSource, bool> predicate)
{
return FirstOrDefault(Where(source, predicate));
}
private static TSource FirstOrDefaultInternal<TSource>(IObservable<TSource> source, bool throwOnEmpty)
{
using (var consumer = new FirstBlocking<TSource>())
{
using (source.Subscribe(consumer))
{
consumer.Wait();
}
consumer._error.ThrowIfNotNull();
if (throwOnEmpty && !consumer._hasValue)
{
throw new InvalidOperationException(Strings_Linq.NO_ELEMENTS);
}
return consumer._value;
}
}
#endregion
#region + ForEach +
public virtual void ForEach<TSource>(IObservable<TSource> source, Action<TSource> onNext)
{
using (var evt = new WaitAndSetOnce())
{
var sink = new ForEach<TSource>.Observer(onNext, () => evt.Set());
using (source.SubscribeSafe(sink))
{
evt.WaitOne();
}
sink.Error.ThrowIfNotNull();
}
}
public virtual void ForEach<TSource>(IObservable<TSource> source, Action<TSource, int> onNext)
{
using (var evt = new WaitAndSetOnce())
{
var sink = new ForEach<TSource>.ObserverIndexed(onNext, () => evt.Set());
using (source.SubscribeSafe(sink))
{
evt.WaitOne();
}
sink.Error.ThrowIfNotNull();
}
}
#endregion
#region + GetEnumerator +
public virtual IEnumerator<TSource> GetEnumerator<TSource>(IObservable<TSource> source)
{
var e = new GetEnumerator<TSource>();
return e.Run(source);
}
#endregion
#region Last
public virtual TSource Last<TSource>(IObservable<TSource> source)
{
return LastOrDefaultInternal(source, true);
}
public virtual TSource Last<TSource>(IObservable<TSource> source, Func<TSource, bool> predicate)
{
return Last(Where(source, predicate));
}
#endregion
#region LastOrDefault
public virtual TSource LastOrDefault<TSource>(IObservable<TSource> source)
{
return LastOrDefaultInternal(source, false);
}
public virtual TSource LastOrDefault<TSource>(IObservable<TSource> source, Func<TSource, bool> predicate)
{
return LastOrDefault(Where(source, predicate));
}
private static TSource LastOrDefaultInternal<TSource>(IObservable<TSource> source, bool throwOnEmpty)
{
using (var consumer = new LastBlocking<TSource>())
{
using (source.Subscribe(consumer))
{
consumer.Wait();
}
consumer._error.ThrowIfNotNull();
if (throwOnEmpty && !consumer._hasValue)
{
throw new InvalidOperationException(Strings_Linq.NO_ELEMENTS);
}
return consumer._value;
}
}
#endregion
#region + Latest +
public virtual IEnumerable<TSource> Latest<TSource>(IObservable<TSource> source)
{
return new Latest<TSource>(source);
}
#endregion
#region + MostRecent +
public virtual IEnumerable<TSource> MostRecent<TSource>(IObservable<TSource> source, TSource initialValue)
{
return new MostRecent<TSource>(source, initialValue);
}
#endregion
#region + Next +
public virtual IEnumerable<TSource> Next<TSource>(IObservable<TSource> source)
{
return new Next<TSource>(source);
}
#endregion
#region Single
public virtual TSource Single<TSource>(IObservable<TSource> source)
{
return SingleOrDefaultInternal(source, true);
}
public virtual TSource Single<TSource>(IObservable<TSource> source, Func<TSource, bool> predicate)
{
return Single(Where(source, predicate));
}
#endregion
#region SingleOrDefault
public virtual TSource SingleOrDefault<TSource>(IObservable<TSource> source)
{
return SingleOrDefaultInternal(source, false);
}
public virtual TSource SingleOrDefault<TSource>(IObservable<TSource> source, Func<TSource, bool> predicate)
{
return SingleOrDefault(Where(source, predicate));
}
private static TSource SingleOrDefaultInternal<TSource>(IObservable<TSource> source, bool throwOnEmpty)
{
var value = default(TSource);
var seenValue = false;
var ex = default(Exception);
using (var evt = new WaitAndSetOnce())
{
//
// [OK] Use of unsafe Subscribe: fine to throw to our caller, behavior indistinguishable from going through the sink.
//
using (source.Subscribe/*Unsafe*/(new AnonymousObserver<TSource>(
v =>
{
if (seenValue)
{
ex = new InvalidOperationException(Strings_Linq.MORE_THAN_ONE_ELEMENT);
evt.Set();
}
value = v;
seenValue = true;
},
e =>
{
ex = e;
evt.Set();
},
() =>
{
evt.Set();
})))
{
evt.WaitOne();
}
}
ex.ThrowIfNotNull();
if (throwOnEmpty && !seenValue)
{
throw new InvalidOperationException(Strings_Linq.NO_ELEMENTS);
}
return value;
}
#endregion
#region Wait
public virtual TSource Wait<TSource>(IObservable<TSource> source)
{
return LastOrDefaultInternal(source, true);
}
#endregion
#region |> Helpers <|
private class WaitAndSetOnce : IDisposable
{
private readonly ManualResetEvent _evt;
private int _hasSet;
public WaitAndSetOnce()
{
_evt = new ManualResetEvent(false);
}
public void Set()
{
if (Interlocked.Exchange(ref _hasSet, 1) == 0)
{
_evt.Set();
}
}
public void WaitOne()
{
_evt.WaitOne();
}
public void Dispose()
{
#if HAS_MREEXPLICITDISPOSABLE
((IDisposable)_evt).Dispose();
#else
_evt.Dispose();
#endif
}
}
#endregion
}
}