using System;
using System.Threading;
using System.Threading.Tasks;

namespace EC.Onvif.RemoteDiscovery
{
	internal static class ExtensionMethods
	{
		/// <summary>
		/// Used to provide cancellation possibility to any Async Methods returning a Task
		/// </summary>
		internal static async Task<T> WithCancellation<T>(this Task<T> task, CancellationToken cancellationToken)
		{
			var tcs = new TaskCompletionSource<bool>();
			using (cancellationToken.Register(s => ((TaskCompletionSource<bool>)s).TrySetResult(true), tcs))
			{
				if (task != await Task.WhenAny(task, tcs.Task))
				{
					throw new OperationCanceledException(cancellationToken);
				}
			}
			return await task;
		}
	}
}