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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.Collections.Generic;
using System.Reactive.Disposables;
#if !NO_TPL
using System.Threading;
using System.Threading.Tasks;
#endif
namespace System.Reactive.Linq.ObservableImpl
{
class Merge<TSource> : Producer<TSource>
{
private readonly IObservable<IObservable<TSource>> _sources;
private readonly int _maxConcurrent;
public Merge(IObservable<IObservable<TSource>> sources)
{
_sources = sources;
}
public Merge(IObservable<IObservable<TSource>> sources, int maxConcurrent)
{
_sources = sources;
_maxConcurrent = maxConcurrent;
}
#if !NO_TPL
private readonly IObservable<Task<TSource>> _sourcesT;
public Merge(IObservable<Task<TSource>> sources)
{
_sourcesT = sources;
}
#endif
protected override IDisposable Run(IObserver<TSource> observer, IDisposable cancel, Action<IDisposable> setSink)
{
if (_maxConcurrent > 0)
{
var sink = new MergeConcurrent(this, observer, cancel);
setSink(sink);
return sink.Run();
}
#if !NO_TPL
else if (_sourcesT != null)
{
var sink = new MergeImpl(this, observer, cancel);
setSink(sink);
return sink.Run();
}
#endif
else
{
var sink = new _(this, observer, cancel);
setSink(sink);
return sink.Run();
}
}
class _ : Sink<TSource>, IObserver<IObservable<TSource>>
{
private readonly Merge<TSource> _parent;
public _(Merge<TSource> parent, IObserver<TSource> observer, IDisposable cancel)
: base(observer, cancel)
{
_parent = parent;
}
private object _gate;
private bool _isStopped;
private CompositeDisposable _group;
private SingleAssignmentDisposable _sourceSubscription;
public IDisposable Run()
{
_gate = new object();
_isStopped = false;
_group = new CompositeDisposable();
_sourceSubscription = new SingleAssignmentDisposable();
_group.Add(_sourceSubscription);
_sourceSubscription.Disposable = _parent._sources.SubscribeSafe(this);
return _group;
}
public void OnNext(IObservable<TSource> value)
{
var innerSubscription = new SingleAssignmentDisposable();
_group.Add(innerSubscription);
innerSubscription.Disposable = value.SubscribeSafe(new Iter(this, innerSubscription));
}
public void OnError(Exception error)
{
lock (_gate)
{
base._observer.OnError(error);
base.Dispose();
}
}
public void OnCompleted()
{
_isStopped = true;
if (_group.Count == 1)
{
//
// Notice there can be a race between OnCompleted of the source and any
// of the inner sequences, where both see _group.Count == 1, and one is
// waiting for the lock. There won't be a double OnCompleted observation
// though, because the call to Dispose silences the observer by swapping
// in a NopObserver<T>.
//
lock (_gate)
{
base._observer.OnCompleted();
base.Dispose();
}
}
else
{
_sourceSubscription.Dispose();
}
}
class Iter : IObserver<TSource>
{
private readonly _ _parent;
private readonly IDisposable _self;
public Iter(_ parent, IDisposable self)
{
_parent = parent;
_self = self;
}
public void OnNext(TSource value)
{
lock (_parent._gate)
_parent._observer.OnNext(value);
}
public void OnError(Exception error)
{
lock (_parent._gate)
{
_parent._observer.OnError(error);
_parent.Dispose();
}
}
public void OnCompleted()
{
_parent._group.Remove(_self);
if (_parent._isStopped && _parent._group.Count == 1)
{
//
// Notice there can be a race between OnCompleted of the source and any
// of the inner sequences, where both see _group.Count == 1, and one is
// waiting for the lock. There won't be a double OnCompleted observation
// though, because the call to Dispose silences the observer by swapping
// in a NopObserver<T>.
//
lock (_parent._gate)
{
_parent._observer.OnCompleted();
_parent.Dispose();
}
}
}
}
}
class MergeConcurrent : Sink<TSource>, IObserver<IObservable<TSource>>
{
private readonly Merge<TSource> _parent;
public MergeConcurrent(Merge<TSource> parent, IObserver<TSource> observer, IDisposable cancel)
: base(observer, cancel)
{
_parent = parent;
}
private object _gate;
private Queue<IObservable<TSource>> _q;
private bool _isStopped;
private SingleAssignmentDisposable _sourceSubscription;
private CompositeDisposable _group;
private int _activeCount = 0;
public IDisposable Run()
{
_gate = new object();
_q = new Queue<IObservable<TSource>>();
_isStopped = false;
_activeCount = 0;
_group = new CompositeDisposable();
_sourceSubscription = new SingleAssignmentDisposable();
_sourceSubscription.Disposable = _parent._sources.SubscribeSafe(this);
_group.Add(_sourceSubscription);
return _group;
}
public void OnNext(IObservable<TSource> value)
{
lock (_gate)
{
if (_activeCount < _parent._maxConcurrent)
{
_activeCount++;
Subscribe(value);
}
else
_q.Enqueue(value);
}
}
public void OnError(Exception error)
{
lock (_gate)
{
base._observer.OnError(error);
base.Dispose();
}
}
public void OnCompleted()
{
lock (_gate)
{
_isStopped = true;
if (_activeCount == 0)
{
base._observer.OnCompleted();
base.Dispose();
}
else
{
_sourceSubscription.Dispose();
}
}
}
private void Subscribe(IObservable<TSource> innerSource)
{
var subscription = new SingleAssignmentDisposable();
_group.Add(subscription);
subscription.Disposable = innerSource.SubscribeSafe(new Iter(this, subscription));
}
class Iter : IObserver<TSource>
{
private readonly MergeConcurrent _parent;
private readonly IDisposable _self;
public Iter(MergeConcurrent parent, IDisposable self)
{
_parent = parent;
_self = self;
}
public void OnNext(TSource value)
{
lock (_parent._gate)
_parent._observer.OnNext(value);
}
public void OnError(Exception error)
{
lock (_parent._gate)
{
_parent._observer.OnError(error);
_parent.Dispose();
}
}
public void OnCompleted()
{
_parent._group.Remove(_self);
lock (_parent._gate)
{
if (_parent._q.Count > 0)
{
var s = _parent._q.Dequeue();
_parent.Subscribe(s);
}
else
{
_parent._activeCount--;
if (_parent._isStopped && _parent._activeCount == 0)
{
_parent._observer.OnCompleted();
_parent.Dispose();
}
}
}
}
}
}
#if !NO_TPL
#pragma warning disable 0420
class MergeImpl : Sink<TSource>, IObserver<Task<TSource>>
{
private readonly Merge<TSource> _parent;
public MergeImpl(Merge<TSource> parent, IObserver<TSource> observer, IDisposable cancel)
: base(observer, cancel)
{
_parent = parent;
}
private object _gate;
private volatile int _count;
public IDisposable Run()
{
_gate = new object();
_count = 1;
return _parent._sourcesT.SubscribeSafe(this);
}
public void OnNext(Task<TSource> value)
{
Interlocked.Increment(ref _count);
if (value.IsCompleted)
{
OnCompletedTask(value);
}
else
{
value.ContinueWith(OnCompletedTask);
}
}
private void OnCompletedTask(Task<TSource> task)
{
switch (task.Status)
{
case TaskStatus.RanToCompletion:
{
lock (_gate)
base._observer.OnNext(task.Result);
OnCompleted();
}
break;
case TaskStatus.Faulted:
{
lock (_gate)
{
base._observer.OnError(task.Exception.InnerException);
base.Dispose();
}
}
break;
case TaskStatus.Canceled:
{
lock (_gate)
{
base._observer.OnError(new TaskCanceledException(task));
base.Dispose();
}
}
break;
}
}
public void OnError(Exception error)
{
lock (_gate)
{
base._observer.OnError(error);
base.Dispose();
}
}
public void OnCompleted()
{
if (Interlocked.Decrement(ref _count) == 0)
{
lock (_gate)
{
base._observer.OnCompleted();
base.Dispose();
}
}
}
}
#pragma warning restore 0420
#endif
}
}
#endif
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