func newBuffer(promptLen int) *buffer {
b := new(buffer)
_, b.winColumns = term.GetWinsizeInChar()
b.promptLen = promptLen
b.data = make([]int, BufferLen, BufferCap)
return b
}
// Reads charactes from input to write them to output, allowing line editing.
// The errors that could return are to indicate if Ctrl-D was pressed, and for
// both input / output errors.
func (ln *Line) Read() (line string, err os.Error) {
var anotherLine []int // For lines got from history.
var isHistoryUsed bool // If the history has been accessed.
in := bufio.NewReader(input) // Read input.
seq := make([]byte, 2) // For escape sequences.
seq2 := make([]byte, 1) // Extended escape sequences.
// Print the primary prompt.
if err = ln.prompt(); err != nil {
return "", err
}
// === Detect change of window size.
go term.TrapWinsize()
go func() {
for {
<-term.WinsizeChan // Wait for.
_, ln.buf.winColumns = term.GetWinsizeInChar()
ln.buf.refresh()
}
}()
for {
rune, _, err := in.ReadRune()
if err != nil {
return "", inputError(err.String())
}
switch rune {
default:
if err = ln.buf.insertRune(rune); err != nil {
return "", err
}
continue
case 13: // enter
line = ln.buf.toString()
if ln.useHistory {
ln.hist.Add(line)
}
if _, err = output.Write(_CR_LF); err != nil {
return "", outputError(err.String())
}
return strings.TrimSpace(line), nil
case 127, 8: // backspace, Ctrl-h
if err = ln.buf.deletePrev(); err != nil {
return "", err
}
continue
case 9: // horizontal tab
// TODO: disabled by now
continue
case 3: // Ctrl-c
if err = ln.buf.insertRunes(ctrlC); err != nil {
return "", err
}
if _, err = output.Write(_CR_LF); err != nil {
return "", outputError(err.String())
}
if err = ln.prompt(); err != nil {
return "", err
}
continue
case 4: // Ctrl-d
if err = ln.buf.insertRunes(ctrlD); err != nil {
return "", err
}
if _, err = output.Write(_CR_LF); err != nil {
return "", outputError(err.String())
}
return "", ErrCtrlD
// Escape sequence
case 27: // Escape: Ctrl-[ ("033" in octal, "\x1b" in hexadecimal)
if _, err = in.Read(seq); err != nil {
return "", inputError(err.String())
}
if seq[0] == 79 { // 'O'
switch seq[1] {
case 72: // Home: "\x1bOH"
goto _start
case 70: // End: "\x1bOF"
goto _end
}
}
if seq[0] == 91 { // Left square bracket: "["
switch seq[1] {
case 68: // "\x1b[D"
goto _leftArrow
case 67: // "\x1b[C"
goto _rightArrow
case 65, 66: // Up: "\x1b[A"; Down: "\x1b[B"
goto _upDownArrow
}
// Extended escape.
if seq[1] > 48 && seq[1] < 55 {
if _, err = in.Read(seq2); err != nil {
return "", inputError(err.String())
}
if seq2[0] == 126 { // '~'
switch seq[1] {
//case 50: // Insert: "\x1b[2~"
case 51: // Delete: "\x1b[3~"
if err = ln.buf.delete(); err != nil {
return "", err
}
//case 53: // RePag: "\x1b[5~"
//case 54: // AvPag: "\x1b[6~"
}
}
}
}
continue
case 20: // Ctrl-t, swap actual character by the previous one.
if err = ln.buf.swap(); err != nil {
return "", err
}
continue
case 21: // Ctrl+u, delete the whole line.
if err = ln.buf.deleteLine(); err != nil {
return "", err
}
if err = ln.prompt(); err != nil {
return "", err
}
continue
case 11: // Ctrl+k, delete from current to end of line.
if err = ln.buf.deleteRight(); err != nil {
return "", err
}
continue
case 1: // Ctrl+a, go to the start of the line.
goto _start
case 5: // Ctrl+e, go to the end of the line.
goto _end
case 2: // Ctrl-b
goto _leftArrow
case 6: // Ctrl-f
goto _rightArrow
case 16: // Ctrl-p
seq[1] = 65
goto _upDownArrow
case 14: // Ctrl-n
seq[1] = 66
goto _upDownArrow
}
_upDownArrow: // Up and down arrow: history
if !ln.useHistory {
continue
}
// Up
if seq[1] == 65 {
anotherLine, err = ln.hist.Prev()
// Down
} else {
anotherLine, err = ln.hist.Next()
}
if err != nil {
continue
}
// Update the current history entry before to overwrite it with
// the next one.
// TODO: it has to be removed before of to be saved the history
if !isHistoryUsed {
ln.hist.Add(ln.buf.toString())
}
isHistoryUsed = true
ln.buf.grow(len(anotherLine))
ln.buf.size = len(anotherLine) + ln.buf.promptLen
copy(ln.buf.data[ln.ps1Len:], anotherLine)
if err = ln.buf.refresh(); err != nil {
return "", err
}
continue
_leftArrow:
if err = ln.buf.backward(); err != nil {
return "", err
}
continue
_rightArrow:
if err = ln.buf.forward(); err != nil {
return "", err
}
continue
_start:
if err = ln.buf.start(); err != nil {
return "", err
}
continue
_end:
if _, err = ln.buf.end(); err != nil {
return "", err
}
continue
}
return
}