/// <summary>
/// Execute an action on the thread pool after a specified number of milliseconds.
/// </summary>
/// <param name="action">The action to be executed.</param>
/// <param name="delay">The amount of time to wait before execution, in milliseconds.</param>
/// <returns>A cancellation token that can be used to cancel the operation.</returns>
public static ICancellationToken DelayAndExecute(this Action action, int delay)
{
object waitHandleLock = new object();
ManualResetEvent waitObj = new ManualResetEvent(false);
DelayCancellationToken cancellationToken = new DelayCancellationToken(waitObj);
RegisteredWaitHandle waitHandle = null;
WaitOrTimerCallback callback = (state, timeout) =>
{
if (Interlocked.Exchange(ref waitHandleLock, null) == null)
{
waitHandle.Unregister(null);
cancellationToken.Dispose();
}
if (!timeout)
{
return;
}
action();
};
waitHandle = ThreadPool.RegisterWaitForSingleObject(waitObj, callback, null, delay, true);
if (Interlocked.Exchange(ref waitHandleLock, null) == null)
{
waitHandle.Unregister(null);
cancellationToken.Dispose();
}
return(cancellationToken);
}
/// <summary>
/// Execute an action on the thread pool after a specified number of milliseconds.
/// </summary>
/// <param name="action">The action to be executed.</param>
/// <param name="delay">The amount of time to wait before execution, in milliseconds.</param>
/// <returns>A cancellation token that can be used to cancel the operation.</returns>
public static ICancellationToken DelayAndExecute(this Action action, int delay)
{
object waitHandleLock = new object();
ManualResetEvent waitObj = new ManualResetEvent(false);
DelayCancellationToken cancellationToken = new DelayCancellationToken(waitObj);
RegisteredWaitHandle waitHandle = null;
void callback(object state, bool timeout)
{
// Even if the callback timed out, another thread may cancel
// the cancellation token before we are able to dispose of it
// so we explicitly cancel the token in order to be sure
#if !MONO
timeout = timeout && cancellationToken.Cancel();
#else
timeout = !waitObj.WaitOne(0) && cancellationToken.Cancel();
#endif
// Both the callback thread and the caller thread will
// attempt to set the wait handle lock to null, and the
// last one to do so has to unregister and dispose
if (Interlocked.Exchange(ref waitHandleLock, null) == null)
{
waitHandle.Unregister(null);
cancellationToken.Dispose();
}
// If we didn't time out, then the action
// was canceled by another thread
if (!timeout)
{
return;
}
action();
}
waitHandle = ThreadPool.RegisterWaitForSingleObject(waitObj, callback, null, delay, true);
// Both the callback thread and the caller thread will
// attempt to set the wait handle lock to null, and the
// last one to do so has to unregister and dispose
if (Interlocked.Exchange(ref waitHandleLock, null) == null)
{
waitHandle.Unregister(null);
cancellationToken.Dispose();
}
return(cancellationToken);
}
/// <summary>
/// Execute an action on the thread pool after a specified number of milliseconds.
/// </summary>
/// <param name="action">The action to be executed.</param>
/// <param name="delay">The amount of time to wait before execution, in milliseconds.</param>
/// <returns>A cancellation token that can be used to cancel the operation.</returns>
public static ICancellationToken DelayAndExecute(this Action action, int delay)
{
object waitHandleLock = new object();
ManualResetEvent waitObj = new ManualResetEvent(false);
DelayCancellationToken cancellationToken = new DelayCancellationToken(waitObj);
RegisteredWaitHandle waitHandle = null;
WaitOrTimerCallback callback = (state, timeout) =>
{
// Even if the callback timed out, another thread may cancel
// the cancellation token before we are able to dispose of it
// so we explicitly cancel the token in order to be sure
timeout = timeout && cancellationToken.Cancel();
// Both the callback thread and the caller thread will
// attempt to set the wait handle lock to null, and the
// last one to to do so has to unregister and dispose
if (Interlocked.Exchange(ref waitHandleLock, null) == null)
{
waitHandle.Unregister(null);
cancellationToken.Dispose();
}
// If we didn't time out, then the action
// was cancelled by another thread
if (!timeout)
return;
action();
};
waitHandle = ThreadPool.RegisterWaitForSingleObject(waitObj, callback, null, delay, true);
// Both the callback thread and the caller thread will
// attempt to set the wait handle lock to null, and the
// last one to to do so has to unregister and dispose
if (Interlocked.Exchange(ref waitHandleLock, null) == null)
{
waitHandle.Unregister(null);
cancellationToken.Dispose();
}
return cancellationToken;
}
