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// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved. See License.txt in the project root for license information.
#if !NO_PERF
using System;
using System.Reactive.Disposables;
namespace System.Reactive.Linq.ObservableImpl
{
class Switch<TSource> : Producer<TSource>
{
private readonly IObservable<IObservable<TSource>> _sources;
public Switch(IObservable<IObservable<TSource>> sources)
{
_sources = sources;
}
protected override IDisposable Run(IObserver<TSource> observer, IDisposable cancel, Action<IDisposable> setSink)
{
var sink = new _(this, observer, cancel);
setSink(sink);
return sink.Run();
}
class _ : Sink<TSource>, IObserver<IObservable<TSource>>
{
private readonly Switch<TSource> _parent;
public _(Switch<TSource> parent, IObserver<TSource> observer, IDisposable cancel)
: base(observer, cancel)
{
_parent = parent;
}
private object _gate;
private IDisposable _subscription;
private SerialDisposable _innerSubscription;
private bool _isStopped;
private ulong _latest;
private bool _hasLatest;
public IDisposable Run()
{
_gate = new object();
_innerSubscription = new SerialDisposable();
_isStopped = false;
_latest = 0UL;
_hasLatest = false;
var subscription = new SingleAssignmentDisposable();
_subscription = subscription;
subscription.Disposable = _parent._sources.SubscribeSafe(this);
return new CompositeDisposable(_subscription, _innerSubscription);
}
public void OnNext(IObservable<TSource> value)
{
var id = default(ulong);
lock (_gate)
{
id = unchecked(++_latest);
_hasLatest = true;
}
var d = new SingleAssignmentDisposable();
_innerSubscription.Disposable = d;
d.Disposable = value.SubscribeSafe(new Iter(this, id, d));
}
public void OnError(Exception error)
{
lock (_gate)
base._observer.OnError(error);
base.Dispose();
}
public void OnCompleted()
{
lock (_gate)
{
_subscription.Dispose();
_isStopped = true;
if (!_hasLatest)
{
base._observer.OnCompleted();
base.Dispose();
}
}
}
class Iter : IObserver<TSource>
{
private readonly _ _parent;
private readonly ulong _id;
private readonly IDisposable _self;
public Iter(_ parent, ulong id, IDisposable self)
{
_parent = parent;
_id = id;
_self = self;
}
public void OnNext(TSource value)
{
lock (_parent._gate)
{
if (_parent._latest == _id)
_parent._observer.OnNext(value);
}
}
public void OnError(Exception error)
{
lock (_parent._gate)
{
_self.Dispose();
if (_parent._latest == _id)
{
_parent._observer.OnError(error);
_parent.Dispose();
}
}
}
public void OnCompleted()
{
lock (_parent._gate)
{
_self.Dispose();
if (_parent._latest == _id)
{
_parent._hasLatest = false;
if (_parent._isStopped)
{
_parent._observer.OnCompleted();
_parent.Dispose();
}
}
}
}
}
}
}
}
#endif
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