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exp/terminal: split terminal handling from exp/ssh

Browse Source 
This change splits terminal handling from exp/ssh, as suggested
several times in the ssh code review.

shell.go and shell_test.go are copies from exp/ssh with minimal
changes, so don't need another full review. A future CL will remove
that code from exp/ssh.

R=bradfitz, r, dave, rsc
CC=golang-dev
https://golang.org/cl/5278049
This commit is contained in:
Adam Langley 2011-10-18 12:58:57 -04:00
parent ec158f77bd
commit 7bc4f8de0f
6 changed files with 805 additions and 0 deletions
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15
src/pkg/exp/terminal/Makefile Normal file
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@ -0,0 +1,15 @@
# Copyright 2011 The Go Authors. All rights reserved.
# Use of this source code is governed by a BSD-style
# license that can be found in the LICENSE file.
include ../../../Make.inc
TARG=exp/terminal
GOFILES=\
shell.go\
ifneq ($(GOOS),windows)
GOFILES+=terminal.go
endif
include ../../../Make.pkg

359
src/pkg/exp/terminal/shell.go Normal file
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@ -0,0 +1,359 @@
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package terminal
import (
"os"
"io"
)
// Shell contains the state for running a VT100 terminal that is capable of
// reading lines of input.
type Shell struct {
c io.ReadWriter
prompt string
// line is the current line being entered.
line []byte
// pos is the logical position of the cursor in line
pos int
// cursorX contains the current X value of the cursor where the left
// edge is 0. cursorY contains the row number where the first row of
// the current line is 0.
cursorX, cursorY int
// maxLine is the greatest value of cursorY so far.
maxLine int
termWidth, termHeight int
// outBuf contains the terminal data to be sent.
outBuf []byte
// remainder contains the remainder of any partial key sequences after
// a read. It aliases into inBuf.
remainder []byte
inBuf [256]byte
}
// NewShell runs a VT100 terminal on the given ReadWriter. If the ReadWriter is
// a local terminal, that terminal must first have been put into raw mode.
// prompt is a string that is written at the start of each input line (i.e.
// "> ").
func NewShell(c io.ReadWriter, prompt string) *Shell {
return &Shell{
c: c,
prompt: prompt,
termWidth: 80,
termHeight: 24,
}
}
const (
keyCtrlD = 4
keyEnter = '\r'
keyEscape = 27
keyBackspace = 127
keyUnknown = 256 + iota
keyUp
keyDown
keyLeft
keyRight
keyAltLeft
keyAltRight
)
// bytesToKey tries to parse a key sequence from b. If successful, it returns
// the key and the remainder of the input. Otherwise it returns -1.
func bytesToKey(b []byte) (int, []byte) {
if len(b) == 0 {
return -1, nil
}
if b[0] != keyEscape {
return int(b[0]), b[1:]
}
if len(b) >= 3 && b[0] == keyEscape && b[1] == '[' {
switch b[2] {
case 'A':
return keyUp, b[3:]
case 'B':
return keyDown, b[3:]
case 'C':
return keyRight, b[3:]
case 'D':
return keyLeft, b[3:]
}
}
if len(b) >= 6 && b[0] == keyEscape && b[1] == '[' && b[2] == '1' && b[3] == ';' && b[4] == '3' {
switch b[5] {
case 'C':
return keyAltRight, b[6:]
case 'D':
return keyAltLeft, b[6:]
}
}
// If we get here then we have a key that we don't recognise, or a
// partial sequence. It's not clear how one should find the end of a
// sequence without knowing them all, but it seems that [a-zA-Z] only
// appears at the end of a sequence.
for i, c := range b[0:] {
if c >= 'a' && c <= 'z' || c >= 'A' && c <= 'Z' {
return keyUnknown, b[i+1:]
}
}
return -1, b
}
// queue appends data to the end of ss.outBuf
func (ss *Shell) queue(data []byte) {
if len(ss.outBuf)+len(data) > cap(ss.outBuf) {
newOutBuf := make([]byte, len(ss.outBuf), 2*(len(ss.outBuf)+len(data)))
copy(newOutBuf, ss.outBuf)
ss.outBuf = newOutBuf
}
oldLen := len(ss.outBuf)
ss.outBuf = ss.outBuf[:len(ss.outBuf)+len(data)]
copy(ss.outBuf[oldLen:], data)
}
var eraseUnderCursor = []byte{' ', keyEscape, '[', 'D'}
func isPrintable(key int) bool {
return key >= 32 && key < 127
}
// moveCursorToPos appends data to ss.outBuf which will move the cursor to the
// given, logical position in the text.
func (ss *Shell) moveCursorToPos(pos int) {
x := len(ss.prompt) + pos
y := x / ss.termWidth
x = x % ss.termWidth
up := 0
if y < ss.cursorY {
up = ss.cursorY - y
}
down := 0
if y > ss.cursorY {
down = y - ss.cursorY
}
left := 0
if x < ss.cursorX {
left = ss.cursorX - x
}
right := 0
if x > ss.cursorX {
right = x - ss.cursorX
}
movement := make([]byte, 3*(up+down+left+right))
m := movement
for i := 0; i < up; i++ {
m[0] = keyEscape
m[1] = '['
m[2] = 'A'
m = m[3:]
}
for i := 0; i < down; i++ {
m[0] = keyEscape
m[1] = '['
m[2] = 'B'
m = m[3:]
}
for i := 0; i < left; i++ {
m[0] = keyEscape
m[1] = '['
m[2] = 'D'
m = m[3:]
}
for i := 0; i < right; i++ {
m[0] = keyEscape
m[1] = '['
m[2] = 'C'
m = m[3:]
}
ss.cursorX = x
ss.cursorY = y
ss.queue(movement)
}
const maxLineLength = 4096
// handleKey processes the given key and, optionally, returns a line of text
// that the user has entered.
func (ss *Shell) handleKey(key int) (line string, ok bool) {
switch key {
case keyBackspace:
if ss.pos == 0 {
return
}
ss.pos--
copy(ss.line[ss.pos:], ss.line[1+ss.pos:])
ss.line = ss.line[:len(ss.line)-1]
ss.writeLine(ss.line[ss.pos:])
ss.moveCursorToPos(ss.pos)
ss.queue(eraseUnderCursor)
case keyAltLeft:
// move left by a word.
if ss.pos == 0 {
return
}
ss.pos--
for ss.pos > 0 {
if ss.line[ss.pos] != ' ' {
break
}
ss.pos--
}
for ss.pos > 0 {
if ss.line[ss.pos] == ' ' {
ss.pos++
break
}
ss.pos--
}
ss.moveCursorToPos(ss.pos)
case keyAltRight:
// move right by a word.
for ss.pos < len(ss.line) {
if ss.line[ss.pos] == ' ' {
break
}
ss.pos++
}
for ss.pos < len(ss.line) {
if ss.line[ss.pos] != ' ' {
break
}
ss.pos++
}
ss.moveCursorToPos(ss.pos)
case keyLeft:
if ss.pos == 0 {
return
}
ss.pos--
ss.moveCursorToPos(ss.pos)
case keyRight:
if ss.pos == len(ss.line) {
return
}
ss.pos++
ss.moveCursorToPos(ss.pos)
case keyEnter:
ss.moveCursorToPos(len(ss.line))
ss.queue([]byte("\r\n"))
line = string(ss.line)
ok = true
ss.line = ss.line[:0]
ss.pos = 0
ss.cursorX = 0
ss.cursorY = 0
ss.maxLine = 0
default:
if !isPrintable(key) {
return
}
if len(ss.line) == maxLineLength {
return
}
if len(ss.line) == cap(ss.line) {
newLine := make([]byte, len(ss.line), 2*(1+len(ss.line)))
copy(newLine, ss.line)
ss.line = newLine
}
ss.line = ss.line[:len(ss.line)+1]
copy(ss.line[ss.pos+1:], ss.line[ss.pos:])
ss.line[ss.pos] = byte(key)
ss.writeLine(ss.line[ss.pos:])
ss.pos++
ss.moveCursorToPos(ss.pos)
}
return
}
func (ss *Shell) writeLine(line []byte) {
for len(line) != 0 {
if ss.cursorX == ss.termWidth {
ss.queue([]byte("\r\n"))
ss.cursorX = 0
ss.cursorY++
if ss.cursorY > ss.maxLine {
ss.maxLine = ss.cursorY
}
}
remainingOnLine := ss.termWidth - ss.cursorX
todo := len(line)
if todo > remainingOnLine {
todo = remainingOnLine
}
ss.queue(line[:todo])
ss.cursorX += todo
line = line[todo:]
}
}
func (ss *Shell) Write(buf []byte) (n int, err os.Error) {
return ss.c.Write(buf)
}
// ReadLine returns a line of input from the terminal.
func (ss *Shell) ReadLine() (line string, err os.Error) {
ss.writeLine([]byte(ss.prompt))
ss.c.Write(ss.outBuf)
ss.outBuf = ss.outBuf[:0]
for {
// ss.remainder is a slice at the beginning of ss.inBuf
// containing a partial key sequence
readBuf := ss.inBuf[len(ss.remainder):]
var n int
n, err = ss.c.Read(readBuf)
if err != nil {
return
}
if err == nil {
ss.remainder = ss.inBuf[:n+len(ss.remainder)]
rest := ss.remainder
lineOk := false
for !lineOk {
var key int
key, rest = bytesToKey(rest)
if key < 0 {
break
}
if key == keyCtrlD {
return "", os.EOF
}
line, lineOk = ss.handleKey(key)
}
if len(rest) > 0 {
n := copy(ss.inBuf[:], rest)
ss.remainder = ss.inBuf[:n]
} else {
ss.remainder = nil
}
ss.c.Write(ss.outBuf)
ss.outBuf = ss.outBuf[:0]
if lineOk {
return
}
continue
}
}
panic("unreachable")
}

110
src/pkg/exp/terminal/shell_test.go Normal file
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@ -0,0 +1,110 @@
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package terminal
import (
"testing"
"os"
)
type MockTerminal struct {
toSend []byte
bytesPerRead int
received []byte
}
func (c *MockTerminal) Read(data []byte) (n int, err os.Error) {
n = len(data)
if n == 0 {
return
}
if n > len(c.toSend) {
n = len(c.toSend)
}
if n == 0 {
return 0, os.EOF
}
if c.bytesPerRead > 0 && n > c.bytesPerRead {
n = c.bytesPerRead
}
copy(data, c.toSend[:n])
c.toSend = c.toSend[n:]
return
}
func (c *MockTerminal) Write(data []byte) (n int, err os.Error) {
c.received = append(c.received, data...)
return len(data), nil
}
func TestClose(t *testing.T) {
c := &MockTerminal{}
ss := NewShell(c, "> ")
line, err := ss.ReadLine()
if line != "" {
t.Errorf("Expected empty line but got: %s", line)
}
if err != os.EOF {
t.Errorf("Error should have been EOF but got: %s", err)
}
}
var keyPressTests = []struct {
in string
line string
err os.Error
}{
{
"",
"",
os.EOF,
},
{
"\r",
"",
nil,
},
{
"foo\r",
"foo",
nil,
},
{
"a\x1b[Cb\r", // right
"ab",
nil,
},
{
"a\x1b[Db\r", // left
"ba",
nil,
},
{
"a\177b\r", // backspace
"b",
nil,
},
}
func TestKeyPresses(t *testing.T) {
for i, test := range keyPressTests {
for j := 0; j < len(test.in); j++ {
c := &MockTerminal{
toSend: []byte(test.in),
bytesPerRead: j,
}
ss := NewShell(c, "> ")
line, err := ss.ReadLine()
if line != test.line {
t.Errorf("Line resulting from test %d (%d bytes per read) was '%s', expected '%s'", i, j, line, test.line)
break
}
if err != test.err {
t.Errorf("Error resulting from test %d (%d bytes per read) was '%v', expected '%v'", i, j, err, test.err)
break
}
}
}
}

103
src/pkg/exp/terminal/terminal.go Normal file
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@ -0,0 +1,103 @@
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package terminal provides support functions for dealing with terminals, as
// commonly found on UNIX systems.
//
// Putting a terminal into raw mode is the most common requirement:
//
// oldState, err := terminal.MakeRaw(0)
// if err != nil {
// panic(err.String())
// }
// defer terminal.Restore(0, oldState)
package terminal
import (
"os"
"syscall"
"unsafe"
)
// State contains the state of a terminal.
type State struct {
termios syscall.Termios
}
// IsTerminal returns true if the given file descriptor is a terminal.
func IsTerminal(fd int) bool {
var termios syscall.Termios
_, _, e := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), uintptr(syscall.TCGETS), uintptr(unsafe.Pointer(&termios)), 0, 0, 0)
return e == 0
}
// MakeRaw put the terminal connected to the given file descriptor into raw
// mode and returns the previous state of the terminal so that it can be
// restored.
func MakeRaw(fd int) (*State, os.Error) {
var oldState State
if _, _, e := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), uintptr(syscall.TCGETS), uintptr(unsafe.Pointer(&oldState.termios)), 0, 0, 0); e != 0 {
return nil, os.Errno(e)
}
newState := oldState.termios
newState.Iflag &^= syscall.ISTRIP | syscall.INLCR | syscall.ICRNL | syscall.IGNCR | syscall.IXON | syscall.IXOFF
newState.Lflag &^= syscall.ECHO | syscall.ICANON | syscall.ISIG
if _, _, e := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), uintptr(syscall.TCSETS), uintptr(unsafe.Pointer(&newState)), 0, 0, 0); e != 0 {
return nil, os.Errno(e)
}
return &oldState, nil
}
// Restore restores the terminal connected to the given file descriptor to a
// previous state.
func Restore(fd int, state *State) os.Error {
_, _, e := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), uintptr(syscall.TCSETS), uintptr(unsafe.Pointer(&state.termios)), 0, 0, 0)
return os.Errno(e)
}
// ReadPassword reads a line of input from a terminal without local echo. This
// is commonly used for inputting passwords and other sensitive data. The slice
// returned does not include the \n.
func ReadPassword(fd int) ([]byte, os.Error) {
var oldState syscall.Termios
if _, _, e := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), uintptr(syscall.TCGETS), uintptr(unsafe.Pointer(&oldState)), 0, 0, 0); e != 0 {
return nil, os.Errno(e)
}
newState := oldState
newState.Lflag &^= syscall.ECHO
if _, _, e := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), uintptr(syscall.TCSETS), uintptr(unsafe.Pointer(&newState)), 0, 0, 0); e != 0 {
return nil, os.Errno(e)
}
defer func() {
syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), uintptr(syscall.TCSETS), uintptr(unsafe.Pointer(&oldState)), 0, 0, 0)
}()
var buf [16]byte
var ret []byte
for {
n, errno := syscall.Read(fd, buf[:])
if errno != 0 {
return nil, os.Errno(errno)
}
if n == 0 {
if len(ret) == 0 {
return nil, os.EOF
}
break
}
if buf[n-1] == '\n' {
n--
}
ret = append(ret, buf[:n]...)
if n < len(buf) {
break
}
}
return ret, nil
}

107
src/pkg/syscall/types_linux.c
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@ -41,6 +41,7 @@ Input to godefs. See also mkerrors.sh and mkall.sh
#include <linux/filter.h> #include <linux/filter.h>
#include <linux/netlink.h> #include <linux/netlink.h>
#include <linux/rtnetlink.h> #include <linux/rtnetlink.h>
#include <termios.h>
#include <time.h> #include <time.h>
#include <unistd.h> #include <unistd.h>
#include <ustat.h> #include <ustat.h>
@ -288,3 +289,109 @@ struct my_epoll_event {
}; };
typedef struct my_epoll_event $EpollEvent; typedef struct my_epoll_event $EpollEvent;
// Terminal handling
typedef struct termios $Termios;
enum {
$VINTR = VINTR,
$VQUIT = VQUIT,
$VERASE = VERASE,
$VKILL = VKILL,
$VEOF = VEOF,
$VTIME = VTIME,
$VMIN = VMIN,
$VSWTC = VSWTC,
$VSTART = VSTART,
$VSTOP = VSTOP,
$VSUSP = VSUSP,
$VEOL = VEOL,
$VREPRINT = VREPRINT,
$VDISCARD = VDISCARD,
$VWERASE = VWERASE,
$VLNEXT = VLNEXT,
$VEOL2 = VEOL2,
$IGNBRK = IGNBRK,
$BRKINT = BRKINT,
$IGNPAR = IGNPAR,
$PARMRK = PARMRK,
$INPCK = INPCK,
$ISTRIP = ISTRIP,
$INLCR = INLCR,
$IGNCR = IGNCR,
$ICRNL = ICRNL,
$IUCLC = IUCLC,
$IXON = IXON,
$IXANY = IXANY,
$IXOFF = IXOFF,
$IMAXBEL = IMAXBEL,
$IUTF8 = IUTF8,
$OPOST = OPOST,
$OLCUC = OLCUC,
$ONLCR = ONLCR,
$OCRNL = OCRNL,
$ONOCR = ONOCR,
$ONLRET = ONLRET,
$OFILL = OFILL,
$OFDEL = OFDEL,
$B0 = B0,
$B50 = B50,
$B75 = B75,
$B110 = B110,
$B134 = B134,
$B150 = B150,
$B200 = B200,
$B300 = B300,
$B600 = B600,
$B1200 = B1200,
$B1800 = B1800,
$B2400 = B2400,
$B4800 = B4800,
$B9600 = B9600,
$B19200 = B19200,
$B38400 = B38400,
$CSIZE = CSIZE,
$CS5 = CS5,
$CS6 = CS6,
$CS7 = CS7,
$CS8 = CS8,
$CSTOPB = CSTOPB,
$CREAD = CREAD,
$PARENB = PARENB,
$PARODD = PARODD,
$HUPCL = HUPCL,
$CLOCAL = CLOCAL,
$B57600 = B57600,
$B115200 = B115200,
$B230400 = B230400,
$B460800 = B460800,
$B500000 = B500000,
$B576000 = B576000,
$B921600 = B921600,
$B1000000 = B1000000,
$B1152000 = B1152000,
$B1500000 = B1500000,
$B2000000 = B2000000,
$B2500000 = B2500000,
$B3000000 = B3000000,
$B3500000 = B3500000,
$B4000000 = B4000000,
$ISIG = ISIG,
$ICANON = ICANON,
$XCASE = XCASE,
$ECHO = ECHO,
$ECHOE = ECHOE,
$ECHOK = ECHOK,
$ECHONL = ECHONL,
$NOFLSH = NOFLSH,
$TOSTOP = TOSTOP,
$ECHOCTL = ECHOCTL,
$ECHOPRT = ECHOPRT,
$ECHOKE = ECHOKE,
$FLUSHO = FLUSHO,
$PENDIN = PENDIN,
$IEXTEN = IEXTEN,
$TCGETS = TCGETS,
$TCSETS = TCSETS,
};

111
src/pkg/syscall/ztypes_linux_amd64.go
View File

@ -105,6 +105,105 @@ const (
SizeofSockFilter = 0x8 SizeofSockFilter = 0x8
SizeofSockFprog = 0x10 SizeofSockFprog = 0x10
SizeofInotifyEvent = 0x10 SizeofInotifyEvent = 0x10
VINTR = 0
VQUIT = 0x1
VERASE = 0x2
VKILL = 0x3
VEOF = 0x4
VTIME = 0x5
VMIN = 0x6
VSWTC = 0x7
VSTART = 0x8
VSTOP = 0x9
VSUSP = 0xa
VEOL = 0xb
VREPRINT = 0xc
VDISCARD = 0xd
VWERASE = 0xe
VLNEXT = 0xf
VEOL2 = 0x10
IGNBRK = 0x1
BRKINT = 0x2
IGNPAR = 0x4
PARMRK = 0x8
INPCK = 0x10
ISTRIP = 0x20
INLCR = 0x40
IGNCR = 0x80
ICRNL = 0x100
IUCLC = 0x200
IXON = 0x400
IXANY = 0x800
IXOFF = 0x1000
IMAXBEL = 0x2000
IUTF8 = 0x4000
OPOST = 0x1
OLCUC = 0x2
ONLCR = 0x4
OCRNL = 0x8
ONOCR = 0x10
ONLRET = 0x20
OFILL = 0x40
OFDEL = 0x80
B0 = 0
B50 = 0x1
B75 = 0x2
B110 = 0x3
B134 = 0x4
B150 = 0x5
B200 = 0x6
B300 = 0x7
B600 = 0x8
B1200 = 0x9
B1800 = 0xa
B2400 = 0xb
B4800 = 0xc
B9600 = 0xd
B19200 = 0xe
B38400 = 0xf
CSIZE = 0x30
CS5 = 0
CS6 = 0x10
CS7 = 0x20
CS8 = 0x30
CSTOPB = 0x40
CREAD = 0x80
PARENB = 0x100
PARODD = 0x200
HUPCL = 0x400
CLOCAL = 0x800
B57600 = 0x1001
B115200 = 0x1002
B230400 = 0x1003
B460800 = 0x1004
B500000 = 0x1005
B576000 = 0x1006
B921600 = 0x1007
B1000000 = 0x1008
B1152000 = 0x1009
B1500000 = 0x100a
B2000000 = 0x100b
B2500000 = 0x100c
B3000000 = 0x100d
B3500000 = 0x100e
B4000000 = 0x100f
ISIG = 0x1
ICANON = 0x2
XCASE = 0x4
ECHO = 0x8
ECHOE = 0x10
ECHOK = 0x20
ECHONL = 0x40
NOFLSH = 0x80
TOSTOP = 0x100
ECHOCTL = 0x200
ECHOPRT = 0x400
ECHOKE = 0x800
FLUSHO = 0x1000
PENDIN = 0x4000
IEXTEN = 0x8000
TCGETS = 0x5401
TCSETS = 0x5402
) )
// Types // Types
@ -514,3 +613,15 @@ type EpollEvent struct {
Fd int32 Fd int32
Pad int32 Pad int32
} }
type Termios struct {
Iflag uint32
Oflag uint32
Cflag uint32
Lflag uint32
Line uint8
Cc [32]uint8
Pad_godefs_0 [3]byte
Ispeed uint32
Ospeed uint32
}