112 lines
3.2 KiB
C#
112 lines
3.2 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.
|
|
|
|
using System.Collections.Generic;
|
|
|
|
namespace System.Reactive.Linq.ObservableImpl
|
|
{
|
|
internal sealed class MaxBy<TSource, TKey> : Producer<IList<TSource>, MaxBy<TSource, TKey>._>
|
|
{
|
|
private readonly IObservable<TSource> _source;
|
|
private readonly Func<TSource, TKey> _keySelector;
|
|
private readonly IComparer<TKey> _comparer;
|
|
|
|
public MaxBy(IObservable<TSource> source, Func<TSource, TKey> keySelector, IComparer<TKey> comparer)
|
|
{
|
|
_source = source;
|
|
_keySelector = keySelector;
|
|
_comparer = comparer;
|
|
}
|
|
|
|
protected override _ CreateSink(IObserver<IList<TSource>> observer) => new(this, observer);
|
|
|
|
protected override void Run(_ sink) => sink.Run(_source);
|
|
|
|
internal sealed class _ : Sink<TSource, IList<TSource>>
|
|
{
|
|
private readonly Func<TSource, TKey> _keySelector;
|
|
private readonly IComparer<TKey> _comparer;
|
|
private bool _hasValue;
|
|
private TKey? _lastKey;
|
|
private List<TSource> _list;
|
|
|
|
public _(MaxBy<TSource, TKey> parent, IObserver<IList<TSource>> observer)
|
|
: base(observer)
|
|
{
|
|
_keySelector = parent._keySelector;
|
|
_comparer = parent._comparer;
|
|
|
|
_list = new List<TSource>();
|
|
}
|
|
|
|
public override void OnNext(TSource value)
|
|
{
|
|
TKey key;
|
|
try
|
|
{
|
|
key = _keySelector(value);
|
|
}
|
|
catch (Exception ex)
|
|
{
|
|
Cleanup();
|
|
ForwardOnError(ex);
|
|
return;
|
|
}
|
|
|
|
var comparison = 0;
|
|
|
|
if (!_hasValue)
|
|
{
|
|
_hasValue = true;
|
|
_lastKey = key;
|
|
}
|
|
else
|
|
{
|
|
try
|
|
{
|
|
comparison = _comparer.Compare(key, _lastKey!);
|
|
}
|
|
catch (Exception ex)
|
|
{
|
|
Cleanup();
|
|
ForwardOnError(ex);
|
|
return;
|
|
}
|
|
}
|
|
|
|
if (comparison > 0)
|
|
{
|
|
_lastKey = key;
|
|
_list.Clear();
|
|
}
|
|
|
|
if (comparison >= 0)
|
|
{
|
|
_list.Add(value);
|
|
}
|
|
}
|
|
|
|
public override void OnError(Exception error)
|
|
{
|
|
Cleanup();
|
|
base.OnError(error);
|
|
}
|
|
|
|
public override void OnCompleted()
|
|
{
|
|
var list = _list;
|
|
Cleanup();
|
|
ForwardOnNext(list);
|
|
ForwardOnCompleted();
|
|
}
|
|
|
|
private void Cleanup()
|
|
{
|
|
_list = null!;
|
|
_lastKey = default;
|
|
}
|
|
}
|
|
}
|
|
}
|