521 lines
11 KiB
Go
521 lines
11 KiB
Go
// 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 (
|
|
"io"
|
|
"sync"
|
|
)
|
|
|
|
// EscapeCodes contains escape sequences that can be written to the terminal in
|
|
// order to achieve different styles of text.
|
|
type EscapeCodes struct {
|
|
// Foreground colors
|
|
Black, Red, Green, Yellow, Blue, Magenta, Cyan, White []byte
|
|
|
|
// Reset all attributes
|
|
Reset []byte
|
|
}
|
|
|
|
var vt100EscapeCodes = EscapeCodes{
|
|
Black: []byte{keyEscape, '[', '3', '0', 'm'},
|
|
Red: []byte{keyEscape, '[', '3', '1', 'm'},
|
|
Green: []byte{keyEscape, '[', '3', '2', 'm'},
|
|
Yellow: []byte{keyEscape, '[', '3', '3', 'm'},
|
|
Blue: []byte{keyEscape, '[', '3', '4', 'm'},
|
|
Magenta: []byte{keyEscape, '[', '3', '5', 'm'},
|
|
Cyan: []byte{keyEscape, '[', '3', '6', 'm'},
|
|
White: []byte{keyEscape, '[', '3', '7', 'm'},
|
|
|
|
Reset: []byte{keyEscape, '[', '0', 'm'},
|
|
}
|
|
|
|
// Terminal contains the state for running a VT100 terminal that is capable of
|
|
// reading lines of input.
|
|
type Terminal struct {
|
|
// AutoCompleteCallback, if non-null, is called for each keypress
|
|
// with the full input line and the current position of the cursor.
|
|
// If it returns a nil newLine, the key press is processed normally.
|
|
// Otherwise it returns a replacement line and the new cursor position.
|
|
AutoCompleteCallback func(line []byte, pos, key int) (newLine []byte, newPos int)
|
|
|
|
// Escape contains a pointer to the escape codes for this terminal.
|
|
// It's always a valid pointer, although the escape codes themselves
|
|
// may be empty if the terminal doesn't support them.
|
|
Escape *EscapeCodes
|
|
|
|
// lock protects the terminal and the state in this object from
|
|
// concurrent processing of a key press and a Write() call.
|
|
lock sync.Mutex
|
|
|
|
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
|
|
// echo is true if local echo is enabled
|
|
echo bool
|
|
|
|
// 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
|
|
}
|
|
|
|
// NewTerminal 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 NewTerminal(c io.ReadWriter, prompt string) *Terminal {
|
|
return &Terminal{
|
|
Escape: &vt100EscapeCodes,
|
|
c: c,
|
|
prompt: prompt,
|
|
termWidth: 80,
|
|
termHeight: 24,
|
|
echo: true,
|
|
}
|
|
}
|
|
|
|
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 t.outBuf
|
|
func (t *Terminal) queue(data []byte) {
|
|
t.outBuf = append(t.outBuf, data...)
|
|
}
|
|
|
|
var eraseUnderCursor = []byte{' ', keyEscape, '[', 'D'}
|
|
var space = []byte{' '}
|
|
|
|
func isPrintable(key int) bool {
|
|
return key >= 32 && key < 127
|
|
}
|
|
|
|
// moveCursorToPos appends data to t.outBuf which will move the cursor to the
|
|
// given, logical position in the text.
|
|
func (t *Terminal) moveCursorToPos(pos int) {
|
|
if !t.echo {
|
|
return
|
|
}
|
|
|
|
x := len(t.prompt) + pos
|
|
y := x / t.termWidth
|
|
x = x % t.termWidth
|
|
|
|
up := 0
|
|
if y < t.cursorY {
|
|
up = t.cursorY - y
|
|
}
|
|
|
|
down := 0
|
|
if y > t.cursorY {
|
|
down = y - t.cursorY
|
|
}
|
|
|
|
left := 0
|
|
if x < t.cursorX {
|
|
left = t.cursorX - x
|
|
}
|
|
|
|
right := 0
|
|
if x > t.cursorX {
|
|
right = x - t.cursorX
|
|
}
|
|
|
|
t.cursorX = x
|
|
t.cursorY = y
|
|
t.move(up, down, left, right)
|
|
}
|
|
|
|
func (t *Terminal) move(up, down, left, right int) {
|
|
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:]
|
|
}
|
|
|
|
t.queue(movement)
|
|
}
|
|
|
|
func (t *Terminal) clearLineToRight() {
|
|
op := []byte{keyEscape, '[', 'K'}
|
|
t.queue(op)
|
|
}
|
|
|
|
const maxLineLength = 4096
|
|
|
|
// handleKey processes the given key and, optionally, returns a line of text
|
|
// that the user has entered.
|
|
func (t *Terminal) handleKey(key int) (line string, ok bool) {
|
|
switch key {
|
|
case keyBackspace:
|
|
if t.pos == 0 {
|
|
return
|
|
}
|
|
t.pos--
|
|
t.moveCursorToPos(t.pos)
|
|
|
|
copy(t.line[t.pos:], t.line[1+t.pos:])
|
|
t.line = t.line[:len(t.line)-1]
|
|
if t.echo {
|
|
t.writeLine(t.line[t.pos:])
|
|
}
|
|
t.queue(eraseUnderCursor)
|
|
t.moveCursorToPos(t.pos)
|
|
case keyAltLeft:
|
|
// move left by a word.
|
|
if t.pos == 0 {
|
|
return
|
|
}
|
|
t.pos--
|
|
for t.pos > 0 {
|
|
if t.line[t.pos] != ' ' {
|
|
break
|
|
}
|
|
t.pos--
|
|
}
|
|
for t.pos > 0 {
|
|
if t.line[t.pos] == ' ' {
|
|
t.pos++
|
|
break
|
|
}
|
|
t.pos--
|
|
}
|
|
t.moveCursorToPos(t.pos)
|
|
case keyAltRight:
|
|
// move right by a word.
|
|
for t.pos < len(t.line) {
|
|
if t.line[t.pos] == ' ' {
|
|
break
|
|
}
|
|
t.pos++
|
|
}
|
|
for t.pos < len(t.line) {
|
|
if t.line[t.pos] != ' ' {
|
|
break
|
|
}
|
|
t.pos++
|
|
}
|
|
t.moveCursorToPos(t.pos)
|
|
case keyLeft:
|
|
if t.pos == 0 {
|
|
return
|
|
}
|
|
t.pos--
|
|
t.moveCursorToPos(t.pos)
|
|
case keyRight:
|
|
if t.pos == len(t.line) {
|
|
return
|
|
}
|
|
t.pos++
|
|
t.moveCursorToPos(t.pos)
|
|
case keyEnter:
|
|
t.moveCursorToPos(len(t.line))
|
|
t.queue([]byte("\r\n"))
|
|
line = string(t.line)
|
|
ok = true
|
|
t.line = t.line[:0]
|
|
t.pos = 0
|
|
t.cursorX = 0
|
|
t.cursorY = 0
|
|
t.maxLine = 0
|
|
default:
|
|
if t.AutoCompleteCallback != nil {
|
|
t.lock.Unlock()
|
|
newLine, newPos := t.AutoCompleteCallback(t.line, t.pos, key)
|
|
t.lock.Lock()
|
|
|
|
if newLine != nil {
|
|
if t.echo {
|
|
t.moveCursorToPos(0)
|
|
t.writeLine(newLine)
|
|
for i := len(newLine); i < len(t.line); i++ {
|
|
t.writeLine(space)
|
|
}
|
|
t.moveCursorToPos(newPos)
|
|
}
|
|
t.line = newLine
|
|
t.pos = newPos
|
|
return
|
|
}
|
|
}
|
|
if !isPrintable(key) {
|
|
return
|
|
}
|
|
if len(t.line) == maxLineLength {
|
|
return
|
|
}
|
|
if len(t.line) == cap(t.line) {
|
|
newLine := make([]byte, len(t.line), 2*(1+len(t.line)))
|
|
copy(newLine, t.line)
|
|
t.line = newLine
|
|
}
|
|
t.line = t.line[:len(t.line)+1]
|
|
copy(t.line[t.pos+1:], t.line[t.pos:])
|
|
t.line[t.pos] = byte(key)
|
|
if t.echo {
|
|
t.writeLine(t.line[t.pos:])
|
|
}
|
|
t.pos++
|
|
t.moveCursorToPos(t.pos)
|
|
}
|
|
return
|
|
}
|
|
|
|
func (t *Terminal) writeLine(line []byte) {
|
|
for len(line) != 0 {
|
|
remainingOnLine := t.termWidth - t.cursorX
|
|
todo := len(line)
|
|
if todo > remainingOnLine {
|
|
todo = remainingOnLine
|
|
}
|
|
t.queue(line[:todo])
|
|
t.cursorX += todo
|
|
line = line[todo:]
|
|
|
|
if t.cursorX == t.termWidth {
|
|
t.cursorX = 0
|
|
t.cursorY++
|
|
if t.cursorY > t.maxLine {
|
|
t.maxLine = t.cursorY
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
func (t *Terminal) Write(buf []byte) (n int, err error) {
|
|
t.lock.Lock()
|
|
defer t.lock.Unlock()
|
|
|
|
if t.cursorX == 0 && t.cursorY == 0 {
|
|
// This is the easy case: there's nothing on the screen that we
|
|
// have to move out of the way.
|
|
return t.c.Write(buf)
|
|
}
|
|
|
|
// We have a prompt and possibly user input on the screen. We
|
|
// have to clear it first.
|
|
t.move(0 /* up */, 0 /* down */, t.cursorX /* left */, 0 /* right */)
|
|
t.cursorX = 0
|
|
t.clearLineToRight()
|
|
|
|
for t.cursorY > 0 {
|
|
t.move(1 /* up */, 0, 0, 0)
|
|
t.cursorY--
|
|
t.clearLineToRight()
|
|
}
|
|
|
|
if _, err = t.c.Write(t.outBuf); err != nil {
|
|
return
|
|
}
|
|
t.outBuf = t.outBuf[:0]
|
|
|
|
if n, err = t.c.Write(buf); err != nil {
|
|
return
|
|
}
|
|
|
|
t.queue([]byte(t.prompt))
|
|
chars := len(t.prompt)
|
|
if t.echo {
|
|
t.queue(t.line)
|
|
chars += len(t.line)
|
|
}
|
|
t.cursorX = chars % t.termWidth
|
|
t.cursorY = chars / t.termWidth
|
|
t.moveCursorToPos(t.pos)
|
|
|
|
if _, err = t.c.Write(t.outBuf); err != nil {
|
|
return
|
|
}
|
|
t.outBuf = t.outBuf[:0]
|
|
return
|
|
}
|
|
|
|
// ReadPassword temporarily changes the prompt and reads a password, without
|
|
// echo, from the terminal.
|
|
func (t *Terminal) ReadPassword(prompt string) (line string, err error) {
|
|
t.lock.Lock()
|
|
defer t.lock.Unlock()
|
|
|
|
oldPrompt := t.prompt
|
|
t.prompt = prompt
|
|
t.echo = false
|
|
|
|
line, err = t.readLine()
|
|
|
|
t.prompt = oldPrompt
|
|
t.echo = true
|
|
|
|
return
|
|
}
|
|
|
|
// ReadLine returns a line of input from the terminal.
|
|
func (t *Terminal) ReadLine() (line string, err error) {
|
|
t.lock.Lock()
|
|
defer t.lock.Unlock()
|
|
|
|
return t.readLine()
|
|
}
|
|
|
|
func (t *Terminal) readLine() (line string, err error) {
|
|
// t.lock must be held at this point
|
|
|
|
if t.cursorX == 0 && t.cursorY == 0 {
|
|
t.writeLine([]byte(t.prompt))
|
|
t.c.Write(t.outBuf)
|
|
t.outBuf = t.outBuf[:0]
|
|
}
|
|
|
|
for {
|
|
rest := t.remainder
|
|
lineOk := false
|
|
for !lineOk {
|
|
var key int
|
|
key, rest = bytesToKey(rest)
|
|
if key < 0 {
|
|
break
|
|
}
|
|
if key == keyCtrlD {
|
|
return "", io.EOF
|
|
}
|
|
line, lineOk = t.handleKey(key)
|
|
}
|
|
if len(rest) > 0 {
|
|
n := copy(t.inBuf[:], rest)
|
|
t.remainder = t.inBuf[:n]
|
|
} else {
|
|
t.remainder = nil
|
|
}
|
|
t.c.Write(t.outBuf)
|
|
t.outBuf = t.outBuf[:0]
|
|
if lineOk {
|
|
return
|
|
}
|
|
|
|
// t.remainder is a slice at the beginning of t.inBuf
|
|
// containing a partial key sequence
|
|
readBuf := t.inBuf[len(t.remainder):]
|
|
var n int
|
|
|
|
t.lock.Unlock()
|
|
n, err = t.c.Read(readBuf)
|
|
t.lock.Lock()
|
|
|
|
if err != nil {
|
|
return
|
|
}
|
|
|
|
t.remainder = t.inBuf[:n+len(t.remainder)]
|
|
}
|
|
panic("unreachable")
|
|
}
|
|
|
|
// SetPrompt sets the prompt to be used when reading subsequent lines.
|
|
func (t *Terminal) SetPrompt(prompt string) {
|
|
t.lock.Lock()
|
|
defer t.lock.Unlock()
|
|
|
|
t.prompt = prompt
|
|
}
|
|
|
|
func (t *Terminal) SetSize(width, height int) {
|
|
t.lock.Lock()
|
|
defer t.lock.Unlock()
|
|
|
|
t.termWidth, t.termHeight = width, height
|
|
}
|