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|
package scp
import (
"errors"
"fmt"
"io"
"io/ioutil"
"strconv"
"strings"
)
const (
//CopyMessage Copy Message Opcode
CopyMessage = 'C'
//ErrorMessage Error OpCode
ErrorMessage = 0x1
//WarnMessage Warning Opcode
WarnMessage = 0x2
)
//Message is scp control message
type Message struct {
Type byte
Error error
Mode string
Size int64
FileName string
}
func (m *Message) readByte(reader io.Reader) (byte, error) {
buff := make([]byte, 1)
_, err := io.ReadFull(reader, buff)
if err != nil {
return 0, err
}
return buff[0], nil
}
func (m *Message) readOpCode(reader io.Reader) error {
var err error
m.Type, err = m.readByte(reader)
return err
}
//ReadError reads an error message
func (m *Message) ReadError(reader io.Reader) error {
msg, err := ioutil.ReadAll(reader)
if err != nil {
return err
}
m.Error = errors.New(strings.TrimSpace(string(msg)))
return nil
}
func (m *Message) readLine(reader io.Reader) (string, error) {
line := ""
b, err := m.readByte(reader)
if err != nil {
return "", err
}
for b != 10 {
line += string(b)
b, err = m.readByte(reader)
if err != nil {
return "", err
}
}
return line, nil
}
func (m *Message) readCopy(reader io.Reader) error {
line, err := m.readLine(reader)
if err != nil {
return err
}
parts := strings.Split(line, " ")
if len(parts) < 2 {
return errors.New("Invalid copy line: " + line)
}
m.Mode = parts[0]
m.Size, err = strconv.ParseInt(parts[1], 10, 0)
if err != nil {
return err
}
m.FileName = parts[2]
return nil
}
//ReadFrom reads message from reader
func (m *Message) ReadFrom(reader io.Reader) (int64, error) {
err := m.readOpCode(reader)
if err != nil {
return 0, err
}
switch m.Type {
case CopyMessage:
err = m.readCopy(reader)
if err != nil {
return 0, err
}
case ErrorMessage, WarnMessage:
err = m.ReadError(reader)
if err != nil {
return 0, err
}
default:
return 0, fmt.Errorf("Unsupported opcode: %v", m.Type)
}
return m.Size, nil
}
//NewMessageFromReader constructs a new message from a data in reader
func NewMessageFromReader(reader io.Reader) (*Message, error) {
m := new(Message)
_, err := m.ReadFrom(reader)
if err != nil {
return nil, err
}
return m, nil
}
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