1package imapserver

2

3import (

4 "bufio"

5 "io"

6 "net"

7)

8

9// prefixConn is a net.Conn with a buffer from which the first reads are satisfied.

10// used for STARTTLS where already did a buffered read of initial TLS data.

11type prefixConn struct {

12 prefix []byte

13 net.Conn

14}

15

16func (c *prefixConn) Read(buf []byte) (int, error) {

17 if len(c.prefix) > 0 {

18 n := min(len(buf), len(c.prefix))

19 copy(buf[:n], c.prefix[:n])

20 c.prefix = c.prefix[n:]

21 if len(c.prefix) == 0 {

22 c.prefix = nil

23 }

24 return n, nil

25 }

26 return c.Conn.Read(buf)

27}

28

29// xprefixConn returns either the original net.Conn passed as parameter, or returns

30// a *prefixConn returning the buffered data available in br followed data from the

31// net.Conn passed in.

32func xprefixConn(c net.Conn, br *bufio.Reader) net.Conn {

33 n := br.Buffered()

34 if n == 0 {

35 return c

36 }

37

38 buf := make([]byte, n)

39 _, err := io.ReadFull(c, buf)

40 xcheckf(err, "get buffered data")

41 return &prefixConn{buf, c}

42}

43