/// <summary>
/// Cancels a pending request or a running file transfer.
/// </summary>
/// <param name="e"></param>
public Task <bool> CancelAsync(FTEventArgs e)
{
Task <bool> t = parent.Manager.SendPacketAsync(new P06Accepted(false, 7, ProblemCategory.None)); // This packet cancels any request or running transfer.
e.Assign(parent, this); // This assignment is necessary for FTEventArgs to print exceptions and raise events.
e.Finish(success: false);
currentItem = null;
return(t);
}
internal async Task <bool> OnPacketReceivedAsync(P06Accepted packet)
{
const string name = nameof(OnPacketReceivedAsync) + "(" + nameof(P06Accepted) + ")";
if (currentItem == null) // It may be more efficient not to close the connection but only to cancel the file transfer.
{
parent.ExceptionHandler.CloseConnection("InvalidPacket",
"Cannot resume file transfer for the received accepted packet.",
nameof(FTSocket), name);
return(false);
}
if (!packet.Accepted && packet.RelatedPacket == 7) // Cancellation is always made by denying P07OpenFileTransfer
{
if (!currentItem.Finish(success: false))
{
return(false);
}
currentItem = null;
}
else if (packet.Accepted && packet.RelatedPacket == 7)
{
if ((currentItem.Mode == StreamMode.PushHeader || currentItem.Mode == StreamMode.PushFile) &&
!await parent.Manager.SendPacketAsync(new P08FileHeader(currentItem.FileMeta.GetBinaryData(parent.ConnectionVersion.Value))))
{
return(false);
}
// counterpart accepted file transfer -> we have to sent the FileMeta first
// No exceptions here because every request type get's an accepted packet
}
else if (packet.Accepted && packet.RelatedPacket == 8)
{
currentItem.OnFileMetaTransfered();
if (currentItem.Mode == StreamMode.PushFile) // only StreamMode.PushFile wants to receive the file data
{
if (!currentItem.OpenStream())
{
return(false);
}
if (parent.ConnectionVersion <= 2)
{
return(await SendBlockAsync());
}
else
{
return(ThreadPool.QueueUserWorkItem(SendFileAsync));
}
}
else if (currentItem.Mode != StreamMode.PushHeader)
{
parent.ExceptionHandler.CloseConnection("InvalidPacket",
"The running file transfer is not supposed to receive an accepted packet for a file header.",
nameof(FTSocket), name);
return(false);
}
}
else if (packet.Accepted && packet.RelatedPacket == 9)
{
if (parent.ConnectionVersion <= 2)
{
if (currentItem.Mode != StreamMode.PushFile)
{
parent.ExceptionHandler.CloseConnection("InvalidPacket",
"The running file transfer is not supposed to receive an accepted packet for a file data block.",
nameof(FTSocket), name);
return(false);
}
else if (currentItem.Stream != null)
{
return(await SendBlockAsync());
}
else // accept for the last file data block
{
currentItem = null;
}
}
else
{
parent.ExceptionHandler.CloseConnection("InvalidPacket",
"VSL 1.3 does not accept data block acknoledges anymore.",
nameof(FTSocket), name);
return(false);
}
}
return(true);
}