Method WritePacket

IceFireDB-SQLProxy/pkg/mysql/packet/conn.go:179–221

WritePacket: data already has 4 bytes header will modify data inplace

(data []byte)

// WritePacket: data already has 4 bytes header
// will modify data inplace
func (c *Conn) WritePacket(data []byte) error {
	length := len(data) - 4

	for length >= MaxPayloadLen {
		data[0] = 0xff
		data[1] = 0xff
		data[2] = 0xff

		data[3] = c.Sequence

		if n, err := c.Write(data[:4+MaxPayloadLen]); err != nil {
			// return errors.Wrapf(ErrBadConn, "Write(payload portion) failed. err %v", err)
			c.pkgErr = ErrBadConn
			return ErrBadConn
		} else if n != (4 + MaxPayloadLen) {
			// return errors.Wrapf(ErrBadConn, "Write(payload portion) failed. only %v bytes written, while %v expected", n, 4+MaxPayloadLen)
			c.pkgErr = ErrBadConn
			return ErrBadConn
		} else {
			c.Sequence++
			length -= MaxPayloadLen
			data = data[MaxPayloadLen:]
		}
	}

	data[0] = byte(length)
	data[1] = byte(length >> 8)
	data[2] = byte(length >> 16)
	data[3] = c.Sequence

	if n, err := c.Write(data); err != nil {
		// return errors.Wrapf(ErrBadConn, "Write failed. err %v", err)
		c.pkgErr = ErrBadConn
		return ErrBadConn
	} else if n != len(data) {
		// return errors.Wrapf(ErrBadConn, "Write failed. only %v bytes written, while %v expected", n, len(data))
		c.pkgErr = ErrBadConn
		return ErrBadConn
	} else {
		c.Sequence++
		return nil
	}
}

// WriteClearAuthPacket: Client clear text authentication packet
// http://dev.mysql.com/doc/internals/en/connection-phase-packets.html#packet-Protocol::AuthSwitchResponse