1package imapclient

2

3import (

4 "io"

5 "net"

6)

7

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

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

10type prefixConn struct {

11 prefix []byte

12 net.Conn

13}

14

15func (c *prefixConn) Read(buf []byte) (int, error) {

16 if len(c.prefix) > 0 {

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

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

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

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

21 c.prefix = nil

22 }

23 return n, nil

24 }

25 return c.Conn.Read(buf)

26}

27

28// xprefixConn checks if there are any buffered unconsumed reads. If not, it

29// returns c.conn. Otherwise, it returns a *prefixConn from which the buffered data

30// can be read followed by data from c.conn.

31func (c *Conn) xprefixConn() net.Conn {

32 n := c.br.Buffered()

33 if n == 0 {

34 return c.conn

35 }

36

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

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

39 c.xcheckf(err, "get buffered data")

40 return &prefixConn{buf, c.conn}

41}

42