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 := len(buf)

18 if n > len(c.prefix) {

19 n = len(c.prefix)

20 }

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

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

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

24 c.prefix = nil

25 }

26 return n, nil

27 }

28 return c.Conn.Read(buf)

29}

30

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

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

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

34func (c *Conn) xprefixConn() net.Conn {

35 n := c.br.Buffered()

36 if n == 0 {

37 return c.conn

38 }

39

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

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

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

43 return &prefixConn{buf, c.conn}

44}

45