fix: resolve the data race of stdConn on Windows (#235)

acceptor_windows.go

@@ -62,9 +62,9 @@ func (svr *server) listenerRun(lockOSThread bool) {
 			go func() {
 				var buffer [0x10000]byte
 				for {
-					n, err := c.conn.Read(buffer[:])
+					n, err := conn.Read(buffer[:])
 					if err != nil {
-						_ = c.conn.SetReadDeadline(time.Time{})
+						_ = conn.SetReadDeadline(time.Time{})
 						el.ch <- &stderr{c, err}
 						return
 					}

errors/errors.go

@@ -41,6 +41,8 @@ var (
 	ErrUnsupportedUDSProtocol = errors.New("only unix is supported")
 	// ErrUnsupportedPlatform occurs when running gnet on an unsupported platform.
 	ErrUnsupportedPlatform = errors.New("unsupported platform in gnet")
+	// ErrConnectionClosed occurs when the event-loop receives a closed connection.
+	ErrConnectionClosed = errors.New("connection is closed")
 
 	// ================================================= codec errors =================================================.
 

eventloop_windows.go

@@ -84,6 +84,10 @@ func (el *eventloop) loopRun(lockOSThread bool) {
 		case *stdConn:
 			err = el.loopAccept(v)
 		case *tcpConn:
+			if v.c.conn == nil {
+				err = errors.ErrConnectionClosed
+				break
+			}
 			v.c.buffer = v.bb
 			err = el.loopRead(v.c)
 		case *udpConn:
@@ -102,7 +106,7 @@ func (el *eventloop) loopRun(lockOSThread bool) {
 			el.getLogger().Debugf("event-loop(%d) is exiting in terms of the demand from user, %v", el.idx, err)
 			break
 		} else if err != nil {
-			el.getLogger().Errorf("event-loop(%d) is exiting due to the error: %v", el.idx, err)
+			el.getLogger().Debugf("event-loop(%d) got a nonlethal error: %v", el.idx, err)
 		}
 	}
 }