General code refactoring.

Source/MQTTnet/Adapter/MqttChannelAdapter.cs

@@ -59,6 +59,7 @@ namespace MQTTnet.Adapter
         public async Task ConnectAsync(TimeSpan timeout, CancellationToken cancellationToken)
         {
             ThrowIfDisposed();
+            cancellationToken.ThrowIfCancellationRequested();
 
             try
             {
@@ -85,6 +86,7 @@ namespace MQTTnet.Adapter
         public async Task DisconnectAsync(TimeSpan timeout, CancellationToken cancellationToken)
         {
             ThrowIfDisposed();
+            cancellationToken.ThrowIfCancellationRequested();
 
             try
             {
@@ -112,8 +114,17 @@ namespace MQTTnet.Adapter
         public async Task SendPacketAsync(MqttBasePacket packet, TimeSpan timeout, CancellationToken cancellationToken)
         {
             ThrowIfDisposed();
+            cancellationToken.ThrowIfCancellationRequested();
+
+            try
+            {
+                await _writerSemaphore.WaitAsync(cancellationToken).ConfigureAwait(false);
+            }
+            catch (ObjectDisposedException)
+            {
+                throw new OperationCanceledException();
+            }
 
-            await _writerSemaphore.WaitAsync(cancellationToken).ConfigureAwait(false);
             try
             {
                 var packetData = PacketFormatterAdapter.Encode(packet);
@@ -144,13 +155,22 @@ namespace MQTTnet.Adapter
             finally
             {
                 PacketFormatterAdapter.FreeBuffer();
-                _writerSemaphore?.Release();
+
+                try
+                {
+                    _writerSemaphore.Release();
+                }
+                catch (ObjectDisposedException)
+                {
+                    throw new OperationCanceledException();
+                }
             }
         }
 
         public async Task<MqttBasePacket> ReceivePacketAsync(TimeSpan timeout, CancellationToken cancellationToken)
         {
             ThrowIfDisposed();
+            cancellationToken.ThrowIfCancellationRequested();
 
             try
             {
@@ -189,6 +209,9 @@ namespace MQTTnet.Adapter
             catch (OperationCanceledException)
             {
             }
+            catch (ObjectDisposedException)
+            {
+            }
             catch (Exception exception)
             {
                 if (IsWrappedException(exception))
@@ -212,8 +235,8 @@ namespace MQTTnet.Adapter
         {
             if (disposing)
             {
-                _channel?.Dispose();
-                _writerSemaphore?.Dispose();
+                _channel.Dispose();
+                _writerSemaphore.Dispose();
             }
 
             base.Dispose(disposing);

Source/MQTTnet/Implementations/CrossPlatformSocket.cs

@@ -20,7 +20,7 @@ namespace MQTTnet.Implementations
 
         public CrossPlatformSocket()
         {
-            // Having this contructor is important because avoiding the address family as parameter
+            // Having this constructor is important because avoiding the address family as parameter
             // will make use of dual mode in the .net framework.
             _socket = new Socket(SocketType.Stream, ProtocolType.Tcp);
         }
@@ -33,75 +33,34 @@ namespace MQTTnet.Implementations
 
         public bool NoDelay
         {
-            get
-            {
-                return (int)_socket.GetSocketOption(SocketOptionLevel.Tcp, SocketOptionName.NoDelay) > 0;
-            }
-
-            set
-            {
-                _socket.SetSocketOption(SocketOptionLevel.Tcp, SocketOptionName.NoDelay, value ? 1 : 0);
-            }
+            get => (int)_socket.GetSocketOption(SocketOptionLevel.Tcp, SocketOptionName.NoDelay) > 0;
+            set => _socket.SetSocketOption(SocketOptionLevel.Tcp, SocketOptionName.NoDelay, value ? 1 : 0);
         }
 
         public bool DualMode
         {
-            get
-            {
-                return _socket.DualMode;
-            }
-
-            set
-            {
-                _socket.DualMode = value;
-            }
+            get => _socket.DualMode;
+            set => _socket.DualMode = value;
         }
 
         public int ReceiveBufferSize
         {
-            get
-            {
-                return _socket.ReceiveBufferSize;
-            }
-
-            set
-            {
-                _socket.ReceiveBufferSize = value;
-            }
+            get => _socket.ReceiveBufferSize;
+            set => _socket.ReceiveBufferSize = value;
         }
 
         public int SendBufferSize
         {
-            get
-            {
-                return _socket.SendBufferSize;
-            }
-
-            set
-            {
-                _socket.SendBufferSize = value;
-            }
+            get => _socket.SendBufferSize;
+            set => _socket.SendBufferSize = value;
         }
 
-        public EndPoint RemoteEndPoint
-        {
-            get
-            {
-                return _socket.RemoteEndPoint;
-            }
-        }
+        public EndPoint RemoteEndPoint => _socket.RemoteEndPoint;
 
         public bool ReuseAddress
         {
-            get
-            {
-                return (int)_socket.GetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress) != 0;
-            }
-
-            set
-            {
-                _socket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, value ? 1 : 0);
-            }
+            get => (int)_socket.GetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress) != 0;
+            set => _socket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, value ? 1 : 0);
         }
 
         public async Task<CrossPlatformSocket> AcceptAsync()

Source/MQTTnet/Implementations/MqttTcpChannel.Uwp.cs

@@ -17,14 +17,14 @@ using MQTTnet.Server;
 
 namespace MQTTnet.Implementations
 {
-    public class MqttTcpChannel : IMqttChannel
+    public sealed class MqttTcpChannel : IMqttChannel
     {
-        private readonly MqttClientTcpOptions _options;
-        private readonly int _bufferSize;
+        readonly MqttClientTcpOptions _options;
+        readonly int _bufferSize;
 
-        private StreamSocket _socket;
-        private Stream _readStream;
-        private Stream _writeStream;
+        StreamSocket _socket;
+        Stream _readStream;
+        Stream _writeStream;
 
         public MqttTcpChannel(IMqttClientOptions clientOptions)
         {

Source/MQTTnet/Implementations/MqttTcpChannel.cs

@@ -13,7 +13,7 @@ using System.Threading.Tasks;
 
 namespace MQTTnet.Implementations
 {
-    public sealed class MqttTcpChannel : IDisposable, IMqttChannel
+    public sealed class MqttTcpChannel : IMqttChannel
     {
         readonly IMqttClientOptions _clientOptions;
         readonly MqttClientTcpOptions _options;
@@ -162,7 +162,6 @@ namespace MQTTnet.Implementations
             }
             catch (ObjectDisposedException)
             {
-                return;
             }
             catch (IOException exception)
             {
@@ -205,7 +204,6 @@ namespace MQTTnet.Implementations
             {
                 return certificateValidationCallback(x509Certificate, chain, sslPolicyErrors, _clientOptions);
             }
-
 #endregion
 
             var certificateValidationHandler = _options?.TlsOptions?.CertificateValidationHandler;
@@ -229,7 +227,7 @@ namespace MQTTnet.Implementations
 
             if (chain.ChainStatus.Any(c => c.Status == X509ChainStatusFlags.RevocationStatusUnknown || c.Status == X509ChainStatusFlags.Revoked || c.Status == X509ChainStatusFlags.OfflineRevocation))
             {
-                if (!_options.TlsOptions.IgnoreCertificateRevocationErrors)
+                if (_options?.TlsOptions?.IgnoreCertificateRevocationErrors != true)
                 {
                     return false;
                 }
@@ -237,13 +235,13 @@ namespace MQTTnet.Implementations
 
             if (chain.ChainStatus.Any(c => c.Status == X509ChainStatusFlags.PartialChain))
             {
-                if (!_options.TlsOptions.IgnoreCertificateChainErrors)
+                if (_options?.TlsOptions?.IgnoreCertificateChainErrors != true)
                 {
                     return false;
                 }
             }
 
-            return _options.TlsOptions.AllowUntrustedCertificates;
+            return _options?.TlsOptions?.AllowUntrustedCertificates == true;
         }
 
         X509CertificateCollection LoadCertificates()

Source/MQTTnet/Implementations/MqttTcpServerAdapter.cs

@@ -130,7 +130,7 @@ namespace MQTTnet.Implementations
             }
         }
 
-        private Task OnClientAcceptedAsync(IMqttChannelAdapter channelAdapter)
+        Task OnClientAcceptedAsync(IMqttChannelAdapter channelAdapter)
         {
             var clientHandler = ClientHandler;
             if (clientHandler == null)

Source/MQTTnet/Implementations/MqttTcpServerListener.cs

@@ -24,8 +24,8 @@ namespace MQTTnet.Implementations
         readonly MqttServerTlsTcpEndpointOptions _tlsOptions;
         readonly X509Certificate2 _tlsCertificate;
 
-        private CrossPlatformSocket _socket;
-        private IPEndPoint _localEndPoint;
+        CrossPlatformSocket _socket;
+        IPEndPoint _localEndPoint;
 
         public MqttTcpServerListener(
             AddressFamily addressFamily,

Source/MQTTnet/Implementations/MqttWebSocketChannel.cs

@@ -35,7 +35,7 @@ namespace MQTTnet.Implementations
 
         public bool IsSecureConnection { get; private set; }
 
-        public X509Certificate2 ClientCertificate { get; private set; }
+        public X509Certificate2 ClientCertificate { get; }
 
         public async Task ConnectAsync(CancellationToken cancellationToken)
         {

Source/MQTTnet/Server/IMqttServerCertificateCredentials.cs

@@ -1,4 +1,7 @@
-public interface IMqttServerCertificateCredentials
+namespace MQTTnet.Server
 {
-    string Password { get; }
+    public interface IMqttServerCertificateCredentials
+    {
+        string Password { get; }
+    }
 }