UniTask/Assets/UniRx.Async/CancellationTokenExtensions.cs

76 lines
2.3 KiB
C#

#if CSHARP_7_OR_LATER || (UNITY_2018_3_OR_NEWER && (NET_STANDARD_2_0 || NET_4_6))
#pragma warning disable CS1591 // Missing XML comment for publicly visible type or member
using System;
using System.Threading;
namespace UniRx.Async
{
public static class CancellationTokenExtensions
{
static readonly Action<object> cancellationTokenCallback = Callback;
public static (UniTask, CancellationTokenRegistration) ToUniTask(this CancellationToken cts)
{
if (cts.IsCancellationRequested)
{
return (UniTask.FromCanceled(cts), default(CancellationTokenRegistration));
}
var promise = new UniTaskCompletionSource();
return (promise.Task, cts.RegisterWithoutCaptureExecutionContext(cancellationTokenCallback, promise));
}
static void Callback(object state)
{
var promise = (UniTaskCompletionSource)state;
promise.TrySetResult();
}
public static CancellationTokenRegistration RegisterWithoutCaptureExecutionContext(this CancellationToken cancellationToken, Action callback)
{
var restoreFlow = false;
if (!ExecutionContext.IsFlowSuppressed())
{
ExecutionContext.SuppressFlow();
restoreFlow = true;
}
try
{
return cancellationToken.Register(callback, false);
}
finally
{
if (restoreFlow)
{
ExecutionContext.RestoreFlow();
}
}
}
public static CancellationTokenRegistration RegisterWithoutCaptureExecutionContext(this CancellationToken cancellationToken, Action<object> callback, object state)
{
var restoreFlow = false;
if (!ExecutionContext.IsFlowSuppressed())
{
ExecutionContext.SuppressFlow();
restoreFlow = true;
}
try
{
return cancellationToken.Register(callback, state, false);
}
finally
{
if (restoreFlow)
{
ExecutionContext.RestoreFlow();
}
}
}
}
}
#endif