1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
|
package term
import (
"io"
)
// EscapeError is special error which returned by a TTY proxy reader's Read()
// method in case its detach escape sequence is read.
type EscapeError struct{}
func (EscapeError) Error() string {
return "read escape sequence"
}
// escapeProxy is used only for attaches with a TTY. It is used to proxy
// stdin keypresses from the underlying reader and look for the passed in
// escape key sequence to signal a detach.
type escapeProxy struct {
escapeKeys []byte
escapeKeyPos int
r io.Reader
buf []byte
}
// NewEscapeProxy returns a new TTY proxy reader which wraps the given reader
// and detects when the specified escape keys are read, in which case the Read
// method will return an error of type EscapeError.
func NewEscapeProxy(r io.Reader, escapeKeys []byte) io.Reader {
return &escapeProxy{
escapeKeys: escapeKeys,
r: r,
}
}
func (r *escapeProxy) Read(buf []byte) (n int, err error) {
if len(r.escapeKeys) > 0 && r.escapeKeyPos == len(r.escapeKeys) {
return 0, EscapeError{}
}
if len(r.buf) > 0 {
n = copy(buf, r.buf)
r.buf = r.buf[n:]
}
nr, err := r.r.Read(buf[n:])
n += nr
if len(r.escapeKeys) == 0 {
return n, err
}
for i := 0; i < n; i++ {
if buf[i] == r.escapeKeys[r.escapeKeyPos] {
r.escapeKeyPos++
// Check if the full escape sequence is matched.
if r.escapeKeyPos == len(r.escapeKeys) {
n = i + 1 - r.escapeKeyPos
if n < 0 {
n = 0
}
return n, EscapeError{}
}
continue
}
// If we need to prepend a partial escape sequence from the previous
// read, make sure the new buffer size doesn't exceed len(buf).
// Otherwise, preserve any extra data in a buffer for the next read.
if i < r.escapeKeyPos {
preserve := make([]byte, 0, r.escapeKeyPos+n)
preserve = append(preserve, r.escapeKeys[:r.escapeKeyPos]...)
preserve = append(preserve, buf[:n]...)
n = copy(buf, preserve)
i += r.escapeKeyPos
r.buf = append(r.buf, preserve[n:]...)
}
r.escapeKeyPos = 0
}
// If we're in the middle of reading an escape sequence, make sure we don't
// let the caller read it. If later on we find that this is not the escape
// sequence, we'll prepend it back to buf.
n -= r.escapeKeyPos
if n < 0 {
n = 0
}
return n, err
}
|
