improve packets.go

packets.go

@@ -117,6 +117,8 @@ func (mc *mysqlConn) writePacket(data []byte) error {
 		// Write packet
 		if mc.writeTimeout > 0 {
 			if err := mc.netConn.SetWriteDeadline(time.Now().Add(mc.writeTimeout)); err != nil {
+				mc.log(err)
+				mc.cleanup()
 				return err
 			}
 		}
@@ -296,7 +298,7 @@ func (mc *mysqlConn) writeHandshakeResponsePacket(authResp []byte, plugin string
 	data, err := mc.buf.takeBuffer(pktLen + 4)
 	if err != nil {
 		// cannot take the buffer. Something must be wrong with the connection
-		mc.cleanup() // Avoid repeated "busy buffer" errors.
+		mc.cleanup()
 		return err
 	}
 
@@ -515,32 +517,33 @@ func (mc *okHandler) readResultOK() error {
 }
 
 // Result Set Header Packet
-// http://dev.mysql.com/doc/internals/en/com-query-response.html#packet-ProtocolText::Resultset
+// https://dev.mysql.com/doc/dev/mysql-server/latest/page_protocol_com_query_response.html
 func (mc *okHandler) readResultSetHeaderPacket() (int, error) {
 	// handleOkPacket replaces both values; other cases leave the values unchanged.
 	mc.result.affectedRows = append(mc.result.affectedRows, 0)
 	mc.result.insertIds = append(mc.result.insertIds, 0)
 
 	data, err := mc.conn().readPacket()
-	if err == nil {
-		switch data[0] {
-
-		case iOK:
-			return 0, mc.handleOkPacket(data)
+	if err != nil {
+		return 0, err
+	}
 
-		case iERR:
-			return 0, mc.conn().handleErrorPacket(data)
+	switch data[0] {
+	case iOK:
+		return 0, mc.handleOkPacket(data)
 
-		case iLocalInFile:
-			return 0, mc.handleInFileRequest(string(data[1:]))
-		}
+	case iERR:
+		return 0, mc.conn().handleErrorPacket(data)
 
-		// column count
-		num, _, _ := readLengthEncodedInteger(data)
-		// ignore remaining data in the packet. see #1478.
-		return int(num), nil
+	case iLocalInFile:
+		return 0, mc.handleInFileRequest(string(data[1:]))
 	}
-	return 0, err
+
+	// column count
+	// https://dev.mysql.com/doc/dev/mysql-server/latest/page_protocol_com_query_response_text_resultset.html
+	num, _, _ := readLengthEncodedInteger(data)
+	// ignore remaining data in the packet. see #1478.
+	return int(num), nil
 }
 
 // Error Packet