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CrowdControl/Assets/Plugins/UniTask/Runtime/Linq/Take.cs

124 lines
3.8 KiB
C#

2 months ago
using Cysharp.Threading.Tasks.Internal;
using System;
using System.Threading;
namespace Cysharp.Threading.Tasks.Linq
{
public static partial class UniTaskAsyncEnumerable
{
public static IUniTaskAsyncEnumerable<TSource> Take<TSource>(this IUniTaskAsyncEnumerable<TSource> source, Int32 count)
{
Error.ThrowArgumentNullException(source, nameof(source));
return new Take<TSource>(source, count);
}
}
internal sealed class Take<TSource> : IUniTaskAsyncEnumerable<TSource>
{
readonly IUniTaskAsyncEnumerable<TSource> source;
readonly int count;
public Take(IUniTaskAsyncEnumerable<TSource> source, int count)
{
this.source = source;
this.count = count;
}
public IUniTaskAsyncEnumerator<TSource> GetAsyncEnumerator(CancellationToken cancellationToken = default)
{
return new _Take(source, count, cancellationToken);
}
sealed class _Take : MoveNextSource, IUniTaskAsyncEnumerator<TSource>
{
static readonly Action<object> MoveNextCoreDelegate = MoveNextCore;
readonly IUniTaskAsyncEnumerable<TSource> source;
readonly int count;
CancellationToken cancellationToken;
IUniTaskAsyncEnumerator<TSource> enumerator;
UniTask<bool>.Awaiter awaiter;
int index;
public _Take(IUniTaskAsyncEnumerable<TSource> source, int count, CancellationToken cancellationToken)
{
this.source = source;
this.count = count;
this.cancellationToken = cancellationToken;
TaskTracker.TrackActiveTask(this, 3);
}
public TSource Current { get; private set; }
public UniTask<bool> MoveNextAsync()
{
cancellationToken.ThrowIfCancellationRequested();
if (enumerator == null)
{
enumerator = source.GetAsyncEnumerator(cancellationToken);
}
if (checked(index) >= count)
{
return CompletedTasks.False;
}
completionSource.Reset();
SourceMoveNext();
return new UniTask<bool>(this, completionSource.Version);
}
void SourceMoveNext()
{
try
{
awaiter = enumerator.MoveNextAsync().GetAwaiter();
if (awaiter.IsCompleted)
{
MoveNextCore(this);
}
else
{
awaiter.SourceOnCompleted(MoveNextCoreDelegate, this);
}
}
catch (Exception ex)
{
completionSource.TrySetException(ex);
}
}
static void MoveNextCore(object state)
{
var self = (_Take)state;
if (self.TryGetResult(self.awaiter, out var result))
{
if (result)
{
self.index++;
self.Current = self.enumerator.Current;
self.completionSource.TrySetResult(true);
}
else
{
self.completionSource.TrySetResult(false);
}
}
}
public UniTask DisposeAsync()
{
TaskTracker.RemoveTracking(this);
if (enumerator != null)
{
return enumerator.DisposeAsync();
}
return default;
}
}
}
}