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// <copyright>
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
namespace System.Runtime
{
using System;
using System.Threading;
class IOThreadCancellationTokenSource : IDisposable
{
static readonly Action<object> onCancel = Fx.ThunkCallback<object>(OnCancel);
readonly TimeSpan timeout;
CancellationTokenSource source;
CancellationToken? token;
IOThreadTimer timer;
public IOThreadCancellationTokenSource(TimeSpan timeout)
{
TimeoutHelper.ThrowIfNegativeArgument(timeout);
this.timeout = timeout;
}
public IOThreadCancellationTokenSource(int timeout)
: this(TimeSpan.FromMilliseconds(timeout))
{
}
// NOTE: this property is NOT threadsafe. Potential race condition could be caused if you are accessing it
// via different threads.
public CancellationToken Token
{
get
{
if (this.token == null)
{
if (this.timeout >= TimeoutHelper.MaxWait)
{
this.token = CancellationToken.None;
}
else
{
this.timer = new IOThreadTimer(onCancel, this, true);
this.source = new CancellationTokenSource();
this.timer.Set(this.timeout);
this.token = this.source.Token;
}
}
return this.token.Value;
}
}
public void Dispose()
{
if (this.source != null)
{
Fx.Assert(this.timer != null, "timer should not be null.");
if (this.timer.Cancel())
{
this.source.Dispose();
this.source = null;
}
}
}
static void OnCancel(object obj)
{
Fx.Assert(obj != null, "obj should not be null.");
IOThreadCancellationTokenSource thisPtr = (IOThreadCancellationTokenSource)obj;
thisPtr.Cancel();
}
void Cancel()
{
Fx.Assert(this.source != null, "source should not be null.");
this.source.Cancel();
this.source.Dispose();
this.source = null;
}
}
}
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