1// +build !windows
2
3// The terminal mode manipulation code is derived heavily from:
4// https://github.com/golang/crypto/blob/master/ssh/terminal/util.go:
5// Copyright 2011 The Go Authors. All rights reserved.
6// Use of this source code is governed by a BSD-style
7// license that can be found in the LICENSE file.
8
9package terminal
10
11import (
12	"bufio"
13	"bytes"
14	"fmt"
15	"syscall"
16	"unsafe"
17)
18
19type runeReaderState struct {
20	term   syscall.Termios
21	reader *bufio.Reader
22	buf    *bytes.Buffer
23}
24
25func newRuneReaderState(input FileReader) runeReaderState {
26	buf := new(bytes.Buffer)
27	return runeReaderState{
28		reader: bufio.NewReader(&BufferedReader{
29			In:     input,
30			Buffer: buf,
31		}),
32		buf: buf,
33	}
34}
35
36func (rr *RuneReader) Buffer() *bytes.Buffer {
37	return rr.state.buf
38}
39
40// For reading runes we just want to disable echo.
41func (rr *RuneReader) SetTermMode() error {
42	if _, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(rr.stdio.In.Fd()), ioctlReadTermios, uintptr(unsafe.Pointer(&rr.state.term)), 0, 0, 0); err != 0 {
43		return err
44	}
45
46	newState := rr.state.term
47	newState.Lflag &^= syscall.ECHO | syscall.ECHONL | syscall.ICANON | syscall.ISIG
48
49	if _, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(rr.stdio.In.Fd()), ioctlWriteTermios, uintptr(unsafe.Pointer(&newState)), 0, 0, 0); err != 0 {
50		return err
51	}
52
53	return nil
54}
55
56func (rr *RuneReader) RestoreTermMode() error {
57	if _, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(rr.stdio.In.Fd()), ioctlWriteTermios, uintptr(unsafe.Pointer(&rr.state.term)), 0, 0, 0); err != 0 {
58		return err
59	}
60	return nil
61}
62
63func (rr *RuneReader) ReadRune() (rune, int, error) {
64	r, size, err := rr.state.reader.ReadRune()
65	if err != nil {
66		return r, size, err
67	}
68
69	// parse ^[ sequences to look for arrow keys
70	if r == '\033' {
71		if rr.state.reader.Buffered() == 0 {
72			// no more characters so must be `Esc` key
73			return KeyEscape, 1, nil
74		}
75		r, size, err = rr.state.reader.ReadRune()
76		if err != nil {
77			return r, size, err
78		}
79		if r != '[' {
80			return r, size, fmt.Errorf("Unexpected Escape Sequence: %q", []rune{'\033', r})
81		}
82		r, size, err = rr.state.reader.ReadRune()
83		if err != nil {
84			return r, size, err
85		}
86		switch r {
87		case 'D':
88			return KeyArrowLeft, 1, nil
89		case 'C':
90			return KeyArrowRight, 1, nil
91		case 'A':
92			return KeyArrowUp, 1, nil
93		case 'B':
94			return KeyArrowDown, 1, nil
95		case 'H': // Home button
96			return SpecialKeyHome, 1, nil
97		case 'F': // End button
98			return SpecialKeyEnd, 1, nil
99		case '3': // Delete Button
100			// discard the following '~' key from buffer
101			rr.state.reader.Discard(1)
102			return SpecialKeyDelete, 1, nil
103		default:
104			// discard the following '~' key from buffer
105			rr.state.reader.Discard(1)
106			return IgnoreKey, 1, nil
107		}
108		return r, size, fmt.Errorf("Unknown Escape Sequence: %q", []rune{'\033', '[', r})
109	}
110	return r, size, err
111}
112