106 lines
3.1 KiB
C#
106 lines
3.1 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.Generic;
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namespace System.Reactive.Linq.ObservableImpl
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{
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internal sealed class MinBy<TSource, TKey> : Producer<IList<TSource>, MinBy<TSource, TKey>._>
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{
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private readonly IObservable<TSource> _source;
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private readonly Func<TSource, TKey> _keySelector;
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private readonly IComparer<TKey> _comparer;
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public MinBy(IObservable<TSource> source, Func<TSource, TKey> keySelector, IComparer<TKey> comparer)
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{
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_source = source;
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_keySelector = keySelector;
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_comparer = comparer;
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}
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protected override _ CreateSink(IObserver<IList<TSource>> observer) => new(this, observer);
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protected override void Run(_ sink) => sink.Run(_source);
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internal sealed class _ : Sink<TSource, IList<TSource>>
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{
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private readonly Func<TSource, TKey> _keySelector;
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private readonly IComparer<TKey> _comparer;
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private bool _hasValue;
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private TKey? _lastKey;
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private List<TSource> _list;
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public _(MinBy<TSource, TKey> parent, IObserver<IList<TSource>> observer)
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: base(observer)
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{
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_keySelector = parent._keySelector;
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_comparer = parent._comparer;
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_list = new List<TSource>();
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}
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public override void OnNext(TSource value)
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{
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TKey key;
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try
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{
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key = _keySelector(value);
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}
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catch (Exception ex)
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{
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Cleanup();
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ForwardOnError(ex);
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return;
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}
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var comparison = 0;
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if (!_hasValue)
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{
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_hasValue = true;
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_lastKey = key;
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}
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else
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{
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try
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{
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comparison = _comparer.Compare(key, _lastKey!);
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}
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catch (Exception ex)
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{
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Cleanup();
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ForwardOnError(ex);
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return;
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}
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}
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if (comparison < 0)
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{
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_lastKey = key;
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_list.Clear();
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}
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if (comparison <= 0)
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{
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_list.Add(value);
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}
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}
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public override void OnCompleted()
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{
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var list = _list;
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Cleanup();
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ForwardOnNext(list);
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ForwardOnCompleted();
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}
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private void Cleanup()
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{
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_list = null!;
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_lastKey = default;
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}
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}
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}
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}
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