/// <summary>
/// Cancel the task
/// </summary>
public override void Cancel()
{
if (AbortTransfer != null)
{
AbortTransfer.Cancel();
}
StopReceiving = true;
}
/// <summary>
/// Reject the transfer
/// </summary>
/// <param name="RejectAll">If I have to stop the thread</param>
public void Reject(bool RejectAll = false)
{
try
{
byte[] response = Encoding.UTF8.GetBytes("KO");
Stream.Write(response, 0, response.Length);
}
catch (Exception)
{
AbortTransfer.Cancel();
/*if (RejectAll) */ StopReceiving = true;
return;
}
}
/// <summary>
/// Cancel current transfer
/// </summary>
public override void Cancel()
{
lock (Buffer)
{
// Have to wake up who might be sleeping
Monitor.PulseAll(Buffer);
// I put Cancel here, so that if the loader or sender are waiting for the lock,
// I am sure that they will get the cancellation when they get the lock
// NOTE: I may have been called *BEFORE* even starting the sender and the loader,
// that's why I am checking for null. No worries for Monitor.PulseAll, because it won't wake anyone.
if (AbortTransfer != null)
{
AbortTransfer.Cancel();
}
}
}
/// <summary>
/// Send the file
/// </summary>
private void Transmit()
{
//------------------------------------
// Init
//------------------------------------
long written = 0;
//------------------------------------
// Get the file data
//------------------------------------
Progress.CurrentActivity = "Transferring file...";
while (written < FileSize && !AbortTransfer.IsCancellationRequested)
{
// How much should I write
int get = (int)(FileSize - written < 4096 ? (FileSize - written) : 4096);
byte[] data = new byte[get];
// Try to acquire the buffer. I can't write if nothing's there to write yet, man.
lock (Buffer)
{
if (Buffer.Count == 0)
{
/**
* Read considerations I wrote for Monitor.Wait in Loader's code
**/
if (!AbortTransfer.Token.IsCancellationRequested)
{
Monitor.Wait(Buffer);
}
// Did you wake me up because there's data or because we have to exit?
// Doing break, so it gracefully exits the method
if (AbortTransfer.Token.IsCancellationRequested)
{
break;
}
}
data = Buffer.Dequeue();
// Wake up the sender if it was waiting for a dequeue
Monitor.Pulse(Buffer);
}
//------------------------------------
// Send data
//------------------------------------
try
{
// Send data
Task w = Stream.WriteAsync(data, 0, data.Length);
// I really need the result now. Don't want to send packets out of order.
w.Wait(AbortTransfer.Token);
w.Dispose();
// Update written count
written += get;
Progress.Completion = written;
}
catch (Exception e)
{
lock (Buffer)
{
// I have to notify the Loader that I couldn't write!
// Read the considerations in the Loader.
Monitor.Pulse(Buffer);
// Cancel the loader.
AbortTransfer.Cancel();
if (e is SocketException)
{
Progress.CurrentActivity = "Socket has been closed";
}
else
{
if (e is OperationCanceledException)
{
Progress.CurrentActivity = "Operation cancelled";
}
else
{
Progress.CurrentActivity = "The other peer cancelled the operation";
}
}
Progress.IsError = true;
StopSending = true;
}
}
}
// Send Digest
if (written == FileSize && !AbortTransfer.Token.IsCancellationRequested)
{
lock (this)
{
if (AbortTransfer.Token.IsCancellationRequested)
{
return;
}
if (Buffer.Count == 0)
{
Monitor.Wait(this);
}
if (AbortTransfer.Token.IsCancellationRequested)
{
return;
}
byte[] Digest = Buffer.Dequeue();
using (Task t = Stream.WriteAsync(Digest, 0, 32))
{
t.Wait(AbortTransfer.Token);
}
}
}
}
/// <summary>
/// Load bytes from the disk
/// </summary>
private void Load()
{
//------------------------------------
// Init
//------------------------------------
long read = 0;
// https://stackoverflow.com/questions/34325034/how-do-i-cancel-a-filestream-readasync-request/34325233#34325233
// If no IsAsync is specified, readasync does not really implement cancellation.
// NOTE: I started the project with the name FileShare, without knowing it was included in System.IO...
using (FileStream file = new FileStream(FilePath, FileMode.Open, FileAccess.Read, System.IO.FileShare.Read, 4096))
{
//------------------------------------
// Load data
//------------------------------------
while (read < FileSize && !AbortTransfer.Token.IsCancellationRequested)
{
// How many bytes you should read
// Casted to int as the maximum will always be 4096, which is the defaults size of Read btw
int get = (int)(FileSize - read < 4096 ? (FileSize - read) : 4096);
byte[] _data = new byte[get];
byte[] data;
int _read = 0;
try
{
// Actually load data
// It seems that the overload ReadAsync(byte[], int32, int32, CancellationToken)
// doesn't really support cancellation. So I made it with a Wait(CancellationToken)
using (Task <int> r = file.ReadAsync(_data, 0, get))
{
r.Wait(AbortTransfer.Token);
// Completed?
_read = r.Result;
// As per documentation, ReadAsync reads 0 bytes if EOF is reached,
// I'm checking it anyway...
if (_read == 0)
{
throw new EndOfStreamException();
}
data = new byte[_read];
Array.Copy(_data, data, _read);
}
}
catch (Exception)
{
// Notify the Sender that we must exit
lock (Buffer)
{
// If you're here, it means that you were able to get the lock either
// because the Sender is sending or because it's sleeping.
// In the latter case I *MUST* tell it to wake up and exit
Monitor.Pulse(Buffer);
// Set the cancellation token.
// I *MUST* set the cancellation token *WHILE* still in lock,
// so that i can cancel the operation while the sender is still blocked,
// ensuring that it will catch the cancellation.
AbortTransfer.Cancel();
}
return;
}
//------------------------------------
// Store data on buffer
//------------------------------------
lock (Buffer)
{
// I only allow a maximum number of 5 elements,
// so the >= is useless here.
if (Buffer.Count >= 5)
{
/**
* Note: I have to wrap Monitor.Wait in two if(Token.CancellationRequested)
* because I have to check if task has been cancelled!.
* The first one is because user might have interrupted it OR the sender had an exception.
* The second one is to check if I have been awoken because there is data OR I have to quit.
**/
if (!AbortTransfer.Token.IsCancellationRequested)
{
Monitor.Wait(Buffer);
}
// Did you wake me up because there's data or because we have to exit?
// Doing break, so it gracefully exits the loop
if (AbortTransfer.Token.IsCancellationRequested)
{
break;
}
}
// Put data into buffer
Buffer.Enqueue(data);
// Wake up the Sender if it was sleeping (which is probably so the first time)
Monitor.Pulse(Buffer);
}
// Update how many data I have sent
read += _read;
}
//------------------------------------
// Send Digest
//------------------------------------
if (read == FileSize && !AbortTransfer.Token.IsCancellationRequested)
{
ComputeDigest(file);
}
}
}
