88 lines
2.3 KiB
C#
88 lines
2.3 KiB
C#
// Licensed to the .NET Foundation under one or more agreements.
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// The .NET Foundation licenses this file to you under the MIT License.
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// See the LICENSE file in the project root for more information.
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using System.Collections;
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using System.Collections.Generic;
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using System.Diagnostics.CodeAnalysis;
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using System.Reactive.Disposables;
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namespace System.Reactive.Linq.ObservableImpl
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{
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internal abstract class PushToPullAdapter<TSource, TResult> : IEnumerable<TResult>
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{
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private readonly IObservable<TSource> _source;
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protected PushToPullAdapter(IObservable<TSource> source)
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{
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_source = source;
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}
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IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
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public IEnumerator<TResult> GetEnumerator()
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{
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var res = Run();
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res.SetUpstream(_source.SubscribeSafe(res));
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return res;
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}
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protected abstract PushToPullSink<TSource, TResult> Run();
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}
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internal abstract class PushToPullSink<TSource, TResult> : IObserver<TSource>, IEnumerator<TResult>
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{
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private SingleAssignmentDisposableValue _upstream;
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public abstract void OnNext(TSource value);
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public abstract void OnError(Exception error);
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public abstract void OnCompleted();
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public abstract bool TryMoveNext([MaybeNullWhen(false)] out TResult current);
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private bool _done;
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public bool MoveNext()
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{
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if (!_done)
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{
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if (TryMoveNext(out var current))
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{
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Current = current;
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return true;
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}
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_done = true;
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Dispose();
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}
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return false;
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}
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#nullable disable // NB: Matches the protocol around accessing Current only if MoveNext returns true.
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public TResult Current
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{
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get;
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private set;
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}
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object IEnumerator.Current => Current;
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#nullable restore
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public void Reset()
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{
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throw new NotSupportedException();
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}
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public void Dispose()
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{
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_upstream.Dispose();
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}
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public void SetUpstream(IDisposable d)
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{
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_upstream.Disposable = d;
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}
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}
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}
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