Retro68/gcc/libgo/go/exp/terminal/terminal.go
Wolfgang Thaller aaf905ce07 add gcc 4.70
2012-03-28 01:13:14 +02:00

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
}