Add semaphore for accessing send stream

This commit is contained in:
Christian Kratky
2017-09-28 09:29:47 +02:00
parent e947881aca
commit d09455f78e
2 changed files with 32 additions and 30 deletions
@@ -16,8 +16,7 @@ namespace MQTTnet.Core.Adapter
public class MqttChannelCommunicationAdapter : IMqttCommunicationAdapter
{
private readonly IMqttCommunicationChannel _channel;
private readonly Task _waitTask = Task.FromResult(0); // this task is used to prevent overlapping write
private readonly SemaphoreSlim _semaphore = new SemaphoreSlim(1, 1);
public MqttChannelCommunicationAdapter(IMqttCommunicationChannel channel, IMqttPacketSerializer serializer)
{
@@ -77,32 +76,31 @@ namespace MQTTnet.Core.Adapter
public async Task SendPacketsAsync(TimeSpan timeout, CancellationToken cancellationToken, IEnumerable<MqttBasePacket> packets)
{
await _semaphore.WaitAsync(cancellationToken);
try
{
var waitTask = _waitTask;
foreach (var packet in packets)
{
if (packet == null) { continue; }
MqttTrace.Information(nameof(MqttChannelCommunicationAdapter), $"TX >>> {packet} [Timeout={timeout}]");
var writeBuffer = PacketSerializer.Serialize(packet);
waitTask = waitTask.ContinueWith(t => _channel.SendStream.WriteAsync(writeBuffer, 0, writeBuffer.Length, cancellationToken).ConfigureAwait(false), cancellationToken);
}
waitTask = waitTask.ContinueWith(t =>
{
if (timeout > TimeSpan.Zero)
if (packet == null)
{
return _channel.SendStream.FlushAsync(cancellationToken).TimeoutAfter(timeout).ConfigureAwait(false);
continue;
}
return _channel.SendStream.FlushAsync(cancellationToken).ConfigureAwait(false);
}, cancellationToken);
MqttTrace.Information(nameof(MqttChannelCommunicationAdapter), $"TX >>> {0} [Timeout={1}]", packet, timeout);
await waitTask; // configure await false generates stackoverflow
var writeBuffer = PacketSerializer.Serialize(packet);
await _channel.SendStream.WriteAsync(writeBuffer, 0, writeBuffer.Length, cancellationToken).ConfigureAwait(false);
}
if (timeout > TimeSpan.Zero)
{
await _channel.SendStream.FlushAsync(cancellationToken).TimeoutAfter(timeout).ConfigureAwait(false);
}
else
{
await _channel.SendStream.FlushAsync(cancellationToken).ConfigureAwait(false);
}
}
catch (TaskCanceledException)
{
@@ -120,6 +118,10 @@ namespace MQTTnet.Core.Adapter
{
throw new MqttCommunicationException(exception);
}
finally
{
_semaphore.Release();
}
}
public async Task<MqttBasePacket> ReceivePacketAsync(TimeSpan timeout, CancellationToken cancellationToken)
@@ -113,16 +113,16 @@ namespace MQTTnet.TestApp.NetFramework
.Select(i => CreateMessage())
.ToList();
////if (false)
////{
//// //send concurrent (test for raceconditions)
//// var sendTasks = msgs
//// .Select(msg => PublishSingleMessage(client, msg, ref msgCount))
//// .ToList();
if (true)
{
//send concurrent (test for raceconditions)
var sendTasks = msgs
.Select(msg => PublishSingleMessage(client, msg, ref msgCount))
.ToList();
//// await Task.WhenAll(sendTasks);
////}
////else
await Task.WhenAll(sendTasks);
}
else
{
await client.PublishAsync(msgs);
msgCount += msgs.Count;
@@ -134,7 +134,7 @@ namespace MQTTnet.TestApp.NetFramework
var now = DateTime.Now;
if (last < now - TimeSpan.FromSeconds(1))
{
Console.WriteLine($"sending {msgCount} inteded {msgChunkSize / interval.TotalSeconds}");
Console.WriteLine($"sending {msgCount} intended {msgChunkSize / interval.TotalSeconds}");
msgCount = 0;
last = now;
}