Merge branch 'main' of https://git.whblueocean.cn/communication-protocol/modbus into cfy-feat-fix

Reviewed-on: #10

rtu_transport.go

@@ -465,7 +465,8 @@ func (rt *rtuTransport) readRTUFrameWithRes() (res *pdu, err error) {
 	// 标准modbus响应已读取完成，现在读取自定义数据
 	// 设置5秒超时来读取自定义数据
 	customDataTimeout := 5 * time.Second
-	err = rt.link.SetDeadline(time.Now().Add(customDataTimeout))
+	deadline := time.Now().Add(customDataTimeout)
+	err = rt.link.SetDeadline(deadline)
 	if err != nil {
 		return
 	}
@@ -477,6 +478,16 @@ func (rt *rtuTransport) readRTUFrameWithRes() (res *pdu, err error) {
 	var lastErr error // 记录最后一次非超时错误
 
 	for {
+		// 检查是否已经超时
+		if time.Now().After(deadline) {
+			// 超时时间到，退出循环
+			// 如果有之前记录的错误，使用它；否则err保持为nil（超时是正常的）
+			if lastErr != nil {
+				err = lastErr
+			}
+			break
+		}
+
 		// 检查缓冲区是否还有空间
 		if startPos+totalRead+len(tempBuf) > len(rxbuf) {
 			// 如果缓冲区不够，扩展它
@@ -497,7 +508,7 @@ func (rt *rtuTransport) readRTUFrameWithRes() (res *pdu, err error) {
 		if readErr != nil {
 			if os.IsTimeout(readErr) {
 				// 超时时间到，退出循环
-				// 如果有之前记录的错误，使用它；否则使用超时错误
+				// 如果有之前记录的错误，使用它；否则err保持为nil（超时是正常的）
 				if lastErr != nil {
 					err = lastErr
 				}

serial.go

@@ -1,6 +1,6 @@
 package modbus
 
-import	(
+import (
 	"time"
 
 	"github.com/goburrow/serial"
@@ -10,43 +10,46 @@ import	(
 // 1) satisfy the rtuLink interface and
 // 2) add Read() deadline/timeout support.
 type serialPortWrapper struct {
-	conf		*serialPortConfig
+	conf     *serialPortConfig
-	port		serial.Port
+	port     serial.Port
-	deadline	time.Time
+	deadline time.Time
 }
 
 type serialPortConfig struct {
-	Device		string
+	Device   string
-	Speed		uint
+	Speed    uint
-	DataBits	uint
+	DataBits uint
-	Parity		uint
+	Parity   uint
-	StopBits	uint
+	StopBits uint
 }
 
 func newSerialPortWrapper(conf *serialPortConfig) (spw *serialPortWrapper) {
 	spw = &serialPortWrapper{
-		conf:	conf,
+		conf: conf,
 	}
 
 	return
 }
 
 func (spw *serialPortWrapper) Open() (err error) {
-	var parity	string
+	var parity string
 
 	switch spw.conf.Parity {
-	case PARITY_NONE:	parity	= "N"
+	case PARITY_NONE:
-	case PARITY_EVEN:	parity	= "E"
+		parity = "N"
-	case PARITY_ODD:	parity	= "O"
+	case PARITY_EVEN:
+		parity = "E"
+	case PARITY_ODD:
+		parity = "O"
 	}
 
 	spw.port, err = serial.Open(&serial.Config{
-		Address:	spw.conf.Device,
+		Address:  spw.conf.Device,
-		BaudRate:	int(spw.conf.Speed),
+		BaudRate: int(spw.conf.Speed),
-		DataBits:	int(spw.conf.DataBits),
+		DataBits: int(spw.conf.DataBits),
-		Parity:		parity,
+		Parity:   parity,
-		StopBits:	int(spw.conf.StopBits),
+		StopBits: int(spw.conf.StopBits),
-		Timeout:	10 * time.Millisecond,
+		Timeout:  100 * time.Millisecond,
 	})
 
 	return
@@ -64,11 +67,12 @@ func (spw *serialPortWrapper) Close() (err error) {
 // attempting to read from the serial port.
 // If Read() is called before the deadline, a read attempt to the serial port
 // is made. At this point, one of two things can happen:
-// - the serial port's receive buffer has one or more bytes and port.Read()
+//   - the serial port's receive buffer has one or more bytes and port.Read()
-//   returns immediately (partial or full read),
+//     returns immediately (partial or full read),
-// - the serial port's receive buffer is empty: port.Read() blocks for
+//   - the serial port's receive buffer is empty: port.Read() blocks for
-//   up to 10ms and returns serial.ErrTimeout. The serial timeout error is
+//     up to 10ms and returns serial.ErrTimeout. The serial timeout error is
-//   masked and Read() returns with no data.
+//     masked and Read() returns with no data.
+//
 // As the higher-level methods use io.ReadFull(), Read() will be called
 // as many times as necessary until either enough bytes have been read or an
 // error is returned (ErrRequestTimedOut or any other i/o error).