Kit.Core/LibExternal/System.Reactive/Linq/Observable/Scan.cs

106 lines
3.4 KiB
C#

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT License.
// See the LICENSE file in the project root for more information.
namespace System.Reactive.Linq.ObservableImpl
{
internal sealed class Scan<TSource, TAccumulate> : Producer<TAccumulate, Scan<TSource, TAccumulate>._>
{
private readonly IObservable<TSource> _source;
private readonly TAccumulate _seed;
private readonly Func<TAccumulate, TSource, TAccumulate> _accumulator;
public Scan(IObservable<TSource> source, TAccumulate seed, Func<TAccumulate, TSource, TAccumulate> accumulator)
{
_source = source;
_seed = seed;
_accumulator = accumulator;
}
protected override _ CreateSink(IObserver<TAccumulate> observer) => new(this, observer);
protected override void Run(_ sink) => sink.Run(_source);
internal sealed class _ : Sink<TSource, TAccumulate>
{
private readonly Func<TAccumulate, TSource, TAccumulate> _accumulator;
private TAccumulate _accumulation;
public _(Scan<TSource, TAccumulate> parent, IObserver<TAccumulate> observer)
: base(observer)
{
_accumulator = parent._accumulator;
_accumulation = parent._seed;
}
public override void OnNext(TSource value)
{
try
{
_accumulation = _accumulator(_accumulation, value);
}
catch (Exception exception)
{
ForwardOnError(exception);
return;
}
ForwardOnNext(_accumulation);
}
}
}
internal sealed class Scan<TSource> : Producer<TSource, Scan<TSource>._>
{
private readonly IObservable<TSource> _source;
private readonly Func<TSource, TSource, TSource> _accumulator;
public Scan(IObservable<TSource> source, Func<TSource, TSource, TSource> accumulator)
{
_source = source;
_accumulator = accumulator;
}
protected override _ CreateSink(IObserver<TSource> observer) => new(_accumulator, observer);
protected override void Run(_ sink) => sink.Run(_source);
internal sealed class _ : IdentitySink<TSource>
{
private readonly Func<TSource, TSource, TSource> _accumulator;
private TSource? _accumulation;
private bool _hasAccumulation;
public _(Func<TSource, TSource, TSource> accumulator, IObserver<TSource> observer)
: base(observer)
{
_accumulator = accumulator;
}
public override void OnNext(TSource value)
{
try
{
if (_hasAccumulation)
{
_accumulation = _accumulator(_accumulation!, value);
}
else
{
_accumulation = value;
_hasAccumulation = true;
}
}
catch (Exception exception)
{
ForwardOnError(exception);
return;
}
ForwardOnNext(_accumulation);
}
}
}
}