namespace Nancy.Extensions

{

using System;

using System.IO;

/// <summary>

/// Containing extensions for the <see cref="Stream"/> object.

/// </summary>

public static class StreamExtensions

{

/// <summary>

/// Buffer size for copy operations

/// </summary>

internal const int BufferSize = 4096;

/// <summary>

/// Copies the contents between two <see cref="Stream"/> instances in an async fashion.

/// </summary>

/// <param name="source">The source stream to copy from.</param>

/// <param name="destination">The destination stream to copy to.</param>

/// <param name="onComplete">Delegate that should be invoked when the operation has completed. Will pass the source, destination and exception (if one was thrown) to the function. Can pass in <see langword="null" />.</param>

public static void CopyTo(this Stream source, Stream destination, Action<Stream, Stream, Exception> onComplete)

{

var buffer =

new byte[BufferSize];

Action<Exception> done = e =>

{

if (onComplete != null)

{

onComplete.Invoke(source, destination, e);

}

};

AsyncCallback rc = null;

rc = readResult =>

{

try

{

var read =

source.EndRead(readResult);

if (read <= 0)

{

done.Invoke(null);

return;

}

destination.BeginWrite(buffer, 0, read, writeResult =>

{

try

{

destination.EndWrite(writeResult);

source.BeginRead(buffer, 0, buffer.Length, rc, null);

}

catch (Exception ex)

{

done.Invoke(ex);

}

}, null);

}

catch (Exception ex)

{

done.Invoke(ex);

}

};

source.BeginRead(buffer, 0, buffer.Length, rc, null);

}

}

}