using System ;
using System.Diagnostics ;
using System.Threading ;
using System.Threading.Tasks ;
namespace MediaBrowser.Common.Extensions
{
/// <summary>
/// Extension methods for <see cref="Process"/>.
/// </summary>
public static class ProcessExtensions
{
/// <summary>
/// Asynchronously wait for the process to exit.
/// </summary>
/// <param name="process">The process to wait for.</param>
/// <param name="timeout">The duration to wait before cancelling waiting for the task.</param>
/// <returns>True if the task exited normally, false if the timeout elapsed before the process exited.</returns>
/// <exception cref="InvalidOperationException">If <see cref="Process.EnableRaisingEvents"/> is not set to true for the process.</exception>
public static async Task < bool > WaitForExitAsync ( this Process process , TimeSpan timeout )
{
using ( var cancelTokenSource = new CancellationTokenSource ( timeout ) )
{
return await WaitForExitAsync ( process , cancelTokenSource . Token ) . ConfigureAwait ( false ) ;
}
}
/// <summary>
/// Asynchronously wait for the process to exit.
/// </summary>
/// <param name="process">The process to wait for.</param>
/// <param name="cancelToken">A <see cref="CancellationToken"/> to observe while waiting for the process to exit.</param>
/// <returns>True if the task exited normally, false if cancelled before the process exited.</returns>
public static async Task < bool > WaitForExitAsync ( this Process process , CancellationToken cancelToken )
{
if ( ! process . EnableRaisingEvents )
{
throw new InvalidOperationException ( "EnableRisingEvents must be enabled to async wait for a task to exit." ) ;
}
// Add an event handler for the process exit event
var tcs = new TaskCompletionSource < bool > ( ) ;
process . Exited + = ( _ , _ ) = > tcs . TrySetResult ( true ) ;
// Return immediately if the process has already exited
if ( process . HasExitedSafe ( ) )
{
return true ;
}
// Register with the cancellation token then await
using ( var cancelRegistration = cancelToken . Register ( ( ) = > tcs . TrySetResult ( process . HasExitedSafe ( ) ) ) )
{
return await tcs . Task . ConfigureAwait ( false ) ;
}
}
/// <summary>
/// Gets a value indicating whether the associated process has been terminated using
/// <see cref="Process.HasExited"/>. This is safe to call even if there is no operating system process
/// associated with the <see cref="Process"/>.
/// </summary>
/// <param name="process">The process to check the exit status for.</param>
/// <returns>
/// True if the operating system process referenced by the <see cref="Process"/> component has
/// terminated, or if there is no associated operating system process; otherwise, false.
/// </returns>
private static bool HasExitedSafe ( this Process process )
{
try
{
return process . HasExited ;
}
catch ( InvalidOperationException )
{
return true ;
}
}
}
}