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AsyncLock.cs
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AsyncLock.cs
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using System;
using System.Threading;
using System.Threading.Tasks;
namespace NetWatcher
{
public sealed class AsyncLock
{
private readonly SemaphoreSlim m_semaphore = new SemaphoreSlim(1, 1);
private readonly Task<IDisposable> m_releaser;
public AsyncLock()
{
m_releaser = Task.FromResult((IDisposable)new Releaser(this));
}
public Task<IDisposable> LockAsync()
{
var wait = m_semaphore.WaitAsync();
return wait.IsCompleted ?
m_releaser :
wait.ContinueWith((_, state) => (IDisposable)state,
m_releaser.Result, CancellationToken.None,
TaskContinuationOptions.ExecuteSynchronously, TaskScheduler.Default);
}
private sealed class Releaser : IDisposable
{
private readonly AsyncLock m_toRelease;
internal Releaser(AsyncLock toRelease) { m_toRelease = toRelease; }
public void Dispose() { m_toRelease.m_semaphore.Release(); }
}
}
}