Fixed receiver thread cancellation

Fixed blocking endlessly on port close

Nefarius.Peripherals.SerialPort/CommPortException.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Runtime.InteropServices;
 
 namespace Nefarius.Peripherals.SerialPort;
 
@@ -22,4 +23,14 @@ public class CommPortException : ApplicationException
     public CommPortException(Exception e) : base("Receive Thread Exception", e)
     {
     }
+
+    public CommPortException(string message, int error) : base(message)
+    {
+        Win32Error = error;
+    }
+
+    /// <summary>
+    ///     The Win32 error that caused the exception.
+    /// </summary>
+    public int Win32Error { get; } = Marshal.GetLastWin32Error();
 }

Nefarius.Peripherals.SerialPort/SerialPort.cs

@@ -22,6 +22,7 @@ public partial class SerialPort : IDisposable
     private readonly ManualResetEvent _writeEvent = new(false);
     private bool _auto;
     private bool _checkSends = true;
+    private CancellationTokenSource _cts;
 
     private Handshake _handShake;
     private SafeFileHandle _hPort;
@@ -70,8 +71,12 @@ public partial class SerialPort : IDisposable
         }
 
         _hPort = PInvoke.CreateFile(PortName,
-            (uint)(FILE_ACCESS_RIGHTS.FILE_GENERIC_READ | FILE_ACCESS_RIGHTS.FILE_GENERIC_WRITE), 0,
+            (uint)(FILE_ACCESS_RIGHTS.FILE_GENERIC_READ | FILE_ACCESS_RIGHTS.FILE_GENERIC_WRITE),
-            null, FILE_CREATION_DISPOSITION.OPEN_EXISTING, FILE_FLAGS_AND_ATTRIBUTES.FILE_FLAG_OVERLAPPED, null);
+            0,
+            null,
+            FILE_CREATION_DISPOSITION.OPEN_EXISTING, FILE_FLAGS_AND_ATTRIBUTES.FILE_FLAG_OVERLAPPED,
+            null
+        );
 
         if (_hPort.IsInvalid)
         {
@@ -80,7 +85,7 @@ public partial class SerialPort : IDisposable
                 return false;
             }
 
-            throw new CommPortException("Port Open Failure");
+            throw new CommPortException("Port Open Failure", Marshal.GetLastWin32Error());
         }
 
         _online = true;
@@ -147,6 +152,7 @@ public partial class SerialPort : IDisposable
         _rxException = null;
         _rxExceptionReported = false;
 
+        _cts = new CancellationTokenSource();
         _rxThread = new Thread(ReceiveThread)
         {
             Name = "CommBaseRx", Priority = ThreadPriority.AboveNormal, IsBackground = true
@@ -171,21 +177,25 @@ public partial class SerialPort : IDisposable
     /// </summary>
     public void Close()
     {
-        if (_online)
+        if (!_online)
         {
-            _auto = false;
+            return;
-            BeforeClose(false);
-            InternalClose();
-            _rxException = null;
         }
+
+        _auto = false;
+        BeforeClose(false);
+        InternalClose();
+        _rxException = null;
     }
 
     private void InternalClose()
     {
         PInvoke.CancelIo(_hPort);
+
         if (_rxThread != null)
         {
-            _rxThread.Abort();
+            _cts.Cancel();
+            _rxThread.Join();
             _rxThread = null;
         }
 
@@ -399,6 +409,9 @@ public partial class SerialPort : IDisposable
     {
     }
 
+    /// <summary>
+    ///     Invoked when a single character has been received.
+    /// </summary>
     public event Action<byte> DataReceived;
 
     /// <summary>
@@ -457,7 +470,7 @@ public partial class SerialPort : IDisposable
 
         try
         {
-            while (true)
+            while (!_cts.IsCancellationRequested)
             {
                 COMM_EVENT_MASK eventMask = 0;
 
@@ -474,7 +487,7 @@ public partial class SerialPort : IDisposable
                 {
                     if (Marshal.GetLastWin32Error() == (int)WIN32_ERROR.ERROR_IO_PENDING)
                     {
-                        sg.WaitOne();
+                        WaitHandle.WaitAny(new[] { sg, _cts.Token.WaitHandle });
                     }
                     else
                     {

PInvokeSerialPort.Sample/Program.cs

@@ -20,5 +20,7 @@ internal class Program
         serialPort.Write("START\r\n");
 
         Console.ReadKey();
+
+        serialPort.Close();
     }
 }