Reorganize solution structure.

Source/MQTTnet/Adapter/IMqttChannelAdapter.cs

@@ -0,0 +1,28 @@
+using System;
+using System.Collections.Generic;
+using System.Threading;
+using System.Threading.Tasks;
+using MQTTnet.Packets;
+using MQTTnet.Serializer;
+
+namespace MQTTnet.Adapter
+{
+    public interface IMqttChannelAdapter : IDisposable
+    {
+        string Endpoint { get; }
+
+        IMqttPacketSerializer PacketSerializer { get; }
+
+        event EventHandler ReadingPacketStarted;
+
+        event EventHandler ReadingPacketCompleted;
+
+        Task ConnectAsync(TimeSpan timeout, CancellationToken cancellationToken);
+
+        Task DisconnectAsync(TimeSpan timeout, CancellationToken cancellationToken);
+
+        Task SendPacketsAsync(TimeSpan timeout, IEnumerable<MqttBasePacket> packets, CancellationToken cancellationToken);
+
+        Task<MqttBasePacket> ReceivePacketAsync(TimeSpan timeout, CancellationToken cancellationToken);
+    }
+}

Source/MQTTnet/Adapter/IMqttServerAdapter.cs

@@ -0,0 +1,14 @@
+using System;
+using System.Threading.Tasks;
+using MQTTnet.Server;
+
+namespace MQTTnet.Adapter
+{
+    public interface IMqttServerAdapter : IDisposable
+    {
+        event EventHandler<MqttServerAdapterClientAcceptedEventArgs> ClientAccepted;
+
+        Task StartAsync(IMqttServerOptions options);
+        Task StopAsync();
+    }
+}

Source/MQTTnet/Adapter/MqttChannelAdapter.cs

@@ -0,0 +1,220 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Net.Sockets;
+using System.Runtime.InteropServices;
+using System.Threading;
+using System.Threading.Tasks;
+using MQTTnet.Channel;
+using MQTTnet.Diagnostics;
+using MQTTnet.Exceptions;
+using MQTTnet.Internal;
+using MQTTnet.Packets;
+using MQTTnet.Serializer;
+
+namespace MQTTnet.Adapter
+{
+    public class MqttChannelAdapter : IMqttChannelAdapter
+    {
+        private const uint ErrorOperationAborted = 0x800703E3;
+        private const int ReadBufferSize = 4096;  // TODO: Move buffer size to config
+
+        private readonly IMqttNetChildLogger _logger;
+        private readonly IMqttChannel _channel;
+
+        private bool _isDisposed;
+
+        public MqttChannelAdapter(IMqttChannel channel, IMqttPacketSerializer serializer, IMqttNetChildLogger logger)
+        {
+            if (logger == null) throw new ArgumentNullException(nameof(logger));
+
+            _channel = channel ?? throw new ArgumentNullException(nameof(channel));
+            PacketSerializer = serializer ?? throw new ArgumentNullException(nameof(serializer));
+
+            _logger = logger.CreateChildLogger(nameof(MqttChannelAdapter));
+        }
+
+        public string Endpoint => _channel.Endpoint;
+
+        public IMqttPacketSerializer PacketSerializer { get; }
+
+        public event EventHandler ReadingPacketStarted;
+        public event EventHandler ReadingPacketCompleted;
+
+        public Task ConnectAsync(TimeSpan timeout, CancellationToken cancellationToken)
+        {
+            ThrowIfDisposed();
+            _logger.Verbose("Connecting [Timeout={0}]", timeout);
+
+            return ExecuteAndWrapExceptionAsync(() =>
+                Internal.TaskExtensions.TimeoutAfter(ct => _channel.ConnectAsync(ct), timeout, cancellationToken));
+        }
+
+        public Task DisconnectAsync(TimeSpan timeout, CancellationToken cancellationToken)
+        {
+            ThrowIfDisposed();
+            _logger.Verbose("Disconnecting [Timeout={0}]", timeout);
+
+            return ExecuteAndWrapExceptionAsync(() =>
+                Internal.TaskExtensions.TimeoutAfter(ct => _channel.DisconnectAsync(), timeout, cancellationToken));
+        }
+
+        public async Task SendPacketsAsync(TimeSpan timeout, IEnumerable<MqttBasePacket> packets, CancellationToken cancellationToken)
+        {
+            ThrowIfDisposed();
+
+            foreach (var packet in packets)
+            {
+                await SendPacketAsync(timeout, cancellationToken, packet).ConfigureAwait(false);
+            }
+        }
+
+        private Task SendPacketAsync(TimeSpan timeout, CancellationToken cancellationToken, MqttBasePacket packet)
+        {
+            return ExecuteAndWrapExceptionAsync(() =>
+            {
+                _logger.Verbose("TX >>> {0} [Timeout={1}]", packet, timeout);
+
+                var packetData = PacketSerializer.Serialize(packet);
+
+                return Internal.TaskExtensions.TimeoutAfter(ct => _channel.WriteAsync(
+                    packetData.Array,
+                    packetData.Offset,
+                    packetData.Count,
+                    ct), timeout, cancellationToken);
+            });
+        }
+
+        public async Task<MqttBasePacket> ReceivePacketAsync(TimeSpan timeout, CancellationToken cancellationToken)
+        {
+            ThrowIfDisposed();
+
+            MqttBasePacket packet = null;
+            await ExecuteAndWrapExceptionAsync(async () =>
+            {
+                ReceivedMqttPacket receivedMqttPacket;
+
+                if (timeout > TimeSpan.Zero)
+                {
+                    receivedMqttPacket = await Internal.TaskExtensions.TimeoutAfter(ct => ReceiveAsync(_channel, ct), timeout, cancellationToken).ConfigureAwait(false);
+                }
+                else
+                {
+                    receivedMqttPacket = await ReceiveAsync(_channel, cancellationToken).ConfigureAwait(false);
+                }
+
+                if (receivedMqttPacket == null || cancellationToken.IsCancellationRequested)
+                {
+                    return;
+                }
+
+                packet = PacketSerializer.Deserialize(receivedMqttPacket);
+                if (packet == null)
+                {
+                    throw new MqttProtocolViolationException("Received malformed packet.");
+                }
+
+                _logger.Verbose("RX <<< {0}", packet);
+            }).ConfigureAwait(false);
+
+            return packet;
+        }
+
+        private async Task<ReceivedMqttPacket> ReceiveAsync(IMqttChannel channel, CancellationToken cancellationToken)
+        {
+            var fixedHeader = await MqttPacketReader.ReadFixedHeaderAsync(channel, cancellationToken).ConfigureAwait(false);
+            if (fixedHeader == null)
+            {
+                return null;
+            }
+
+            try
+            {
+                ReadingPacketStarted?.Invoke(this, EventArgs.Empty);
+
+                if (fixedHeader.RemainingLength == 0)
+                {
+                    return new ReceivedMqttPacket(fixedHeader.Flags, null);
+                }
+
+                var body = new byte[fixedHeader.RemainingLength];
+                var bodyOffset = 0;
+                var chunkSize = Math.Min(ReadBufferSize, fixedHeader.RemainingLength);
+
+                do
+                {
+                    var bytesLeft = body.Length - bodyOffset;
+                    if (chunkSize > bytesLeft)
+                    {
+                        chunkSize = bytesLeft;
+                    }
+
+                    var readBytes = await channel.ReadAsync(body, bodyOffset, chunkSize, cancellationToken) .ConfigureAwait(false);
+                    if (readBytes <= 0)
+                    {
+                        ExceptionHelper.ThrowGracefulSocketClose();
+                    }
+
+                    bodyOffset += readBytes;
+                } while (bodyOffset < body.Length);
+
+                return new ReceivedMqttPacket(fixedHeader.Flags, new MqttPacketBodyReader(body));
+            }
+            finally
+            {
+                ReadingPacketCompleted?.Invoke(this, EventArgs.Empty);
+            }
+        }
+
+        private static async Task ExecuteAndWrapExceptionAsync(Func<Task> action)
+        {
+            try
+            {
+                await action().ConfigureAwait(false);
+            }
+            catch (Exception exception)
+            {
+                if (exception is TaskCanceledException ||
+                    exception is OperationCanceledException ||
+                    exception is MqttCommunicationTimedOutException ||
+                    exception is MqttCommunicationException)
+                {
+                    throw;
+                }
+
+                if (exception is IOException && exception.InnerException is SocketException socketException)
+                {
+                    if (socketException.SocketErrorCode == SocketError.ConnectionAborted)
+                    {
+                        throw new OperationCanceledException();
+                    }
+                }
+
+                if (exception is COMException comException)
+                {
+                    if ((uint)comException.HResult == ErrorOperationAborted)
+                    {
+                        throw new OperationCanceledException();
+                    }
+                }
+
+                throw new MqttCommunicationException(exception);
+            }
+        }
+
+        public void Dispose()
+        {
+            _isDisposed = true;
+
+            _channel?.Dispose();
+        }
+
+        private void ThrowIfDisposed()
+        {
+            if (_isDisposed)
+            {
+                throw new ObjectDisposedException(nameof(MqttChannelAdapter));
+            }
+        }
+    }
+}

Source/MQTTnet/Adapter/MqttConnectingFailedException.cs

@@ -0,0 +1,16 @@
+using MQTTnet.Exceptions;
+using MQTTnet.Protocol;
+
+namespace MQTTnet.Adapter
+{
+    public class MqttConnectingFailedException : MqttCommunicationException
+    {
+        public MqttConnectingFailedException(MqttConnectReturnCode returnCode)
+            : base($"Connecting with MQTT server failed ({returnCode}).")
+        {
+            ReturnCode = returnCode;
+        }
+
+        public MqttConnectReturnCode ReturnCode { get; }
+    }
+}

Source/MQTTnet/Adapter/MqttServerAdapterClientAcceptedEventArgs.cs

@@ -0,0 +1,17 @@
+using System;
+using System.Threading.Tasks;
+
+namespace MQTTnet.Adapter
+{
+    public class MqttServerAdapterClientAcceptedEventArgs : EventArgs
+    {
+        public MqttServerAdapterClientAcceptedEventArgs(IMqttChannelAdapter client)
+        {
+            Client = client ?? throw new ArgumentNullException(nameof(client));
+        }
+
+        public IMqttChannelAdapter Client { get; }
+
+        public Task SessionTask { get; set; }
+    }
+}

Source/MQTTnet/Adapter/ReceivedMqttPacket.cs

@@ -0,0 +1,17 @@
+using MQTTnet.Serializer;
+
+namespace MQTTnet.Adapter
+{
+    public class ReceivedMqttPacket
+    {
+        public ReceivedMqttPacket(byte fixedHeader, MqttPacketBodyReader body)
+        {
+            FixedHeader = fixedHeader;
+            Body = body;
+        }
+
+        public byte FixedHeader { get; }
+
+        public MqttPacketBodyReader Body { get; }
+    }
+}