hs9001/liner/input.go
lawl 67050d32b9 Implement bash CTRL-R reverse history
Fork customized liner into own repo bash.
Rename -being and -end options to -after and -before.
2021-08-08 11:40:33 +02:00

392 line
8.1 KiB
Go

package liner
import (
"bufio"
"errors"
"os"
"os/signal"
"strconv"
"strings"
"syscall"
"time"
)
type nexter struct {
r rune
err error
}
// State represents an open terminal
type State struct {
commonState
origMode termios
defaultMode termios
next <-chan nexter
winch chan os.Signal
pending []rune
useCHA bool
}
// NewLiner initializes a new *State, and sets the terminal into raw mode. To
// restore the terminal to its previous state, call State.Close().
func NewLiner() *State {
var s State
s.r = bufio.NewReader(os.Stdin)
s.terminalSupported = TerminalSupported()
if m, err := TerminalMode(); err == nil {
s.origMode = *m.(*termios)
} else {
s.inputRedirected = true
}
if _, err := getMode(syscall.Stdout); err != 0 {
s.outputRedirected = true
}
if s.inputRedirected && s.outputRedirected {
s.terminalSupported = false
}
if s.terminalSupported && !s.inputRedirected && !s.outputRedirected {
mode := s.origMode
mode.Iflag &^= icrnl | inpck | istrip | ixon
mode.Cflag |= cs8
mode.Lflag &^= syscall.ECHO | icanon | iexten
mode.ApplyMode()
winch := make(chan os.Signal, 1)
signal.Notify(winch, syscall.SIGWINCH)
s.winch = winch
s.checkOutput()
}
if !s.outputRedirected {
s.outputRedirected = !s.getColumns()
}
return &s
}
var errTimedOut = errors.New("timeout")
func (s *State) startPrompt() {
if s.terminalSupported {
if m, err := TerminalMode(); err == nil {
s.defaultMode = *m.(*termios)
mode := s.defaultMode
mode.Lflag &^= isig
mode.ApplyMode()
}
}
s.restartPrompt()
}
func (s *State) inputWaiting() bool {
return len(s.next) > 0
}
func (s *State) restartPrompt() {
next := make(chan nexter, 200)
go func() {
for {
var n nexter
n.r, _, n.err = s.r.ReadRune()
next <- n
// Shut down nexter loop when an end condition has been reached
if n.err != nil || n.r == '\n' || n.r == '\r' || n.r == ctrlC || n.r == ctrlD {
close(next)
return
}
}
}()
s.next = next
}
func (s *State) stopPrompt() {
if s.terminalSupported {
s.defaultMode.ApplyMode()
}
}
func (s *State) nextPending(timeout <-chan time.Time) (rune, error) {
select {
case thing, ok := <-s.next:
if !ok {
return 0, ErrInternal
}
if thing.err != nil {
return 0, thing.err
}
s.pending = append(s.pending, thing.r)
return thing.r, nil
case <-timeout:
rv := s.pending[0]
s.pending = s.pending[1:]
return rv, errTimedOut
}
}
func (s *State) readNext() (interface{}, error) {
if len(s.pending) > 0 {
rv := s.pending[0]
s.pending = s.pending[1:]
return rv, nil
}
var r rune
select {
case thing, ok := <-s.next:
if !ok {
return 0, ErrInternal
}
if thing.err != nil {
return nil, thing.err
}
r = thing.r
case <-s.winch:
s.getColumns()
return winch, nil
}
if r != esc {
return r, nil
}
s.pending = append(s.pending, r)
// Wait at most 50 ms for the rest of the escape sequence
// If nothing else arrives, it was an actual press of the esc key
timeout := time.After(50 * time.Millisecond)
flag, err := s.nextPending(timeout)
if err != nil {
if err == errTimedOut {
return flag, nil
}
return unknown, err
}
switch flag {
case '[':
code, err := s.nextPending(timeout)
if err != nil {
if err == errTimedOut {
return code, nil
}
return unknown, err
}
switch code {
case 'A':
s.pending = s.pending[:0] // escape code complete
return up, nil
case 'B':
s.pending = s.pending[:0] // escape code complete
return down, nil
case 'C':
s.pending = s.pending[:0] // escape code complete
return right, nil
case 'D':
s.pending = s.pending[:0] // escape code complete
return left, nil
case 'F':
s.pending = s.pending[:0] // escape code complete
return end, nil
case 'H':
s.pending = s.pending[:0] // escape code complete
return home, nil
case 'Z':
s.pending = s.pending[:0] // escape code complete
return shiftTab, nil
case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
num := []rune{code}
for {
code, err := s.nextPending(timeout)
if err != nil {
if err == errTimedOut {
return code, nil
}
return nil, err
}
switch code {
case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
num = append(num, code)
case ';':
// Modifier code to follow
// This only supports Ctrl-left and Ctrl-right for now
x, _ := strconv.ParseInt(string(num), 10, 32)
if x != 1 {
// Can't be left or right
rv := s.pending[0]
s.pending = s.pending[1:]
return rv, nil
}
num = num[:0]
for {
code, err = s.nextPending(timeout)
if err != nil {
if err == errTimedOut {
rv := s.pending[0]
s.pending = s.pending[1:]
return rv, nil
}
return nil, err
}
switch code {
case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
num = append(num, code)
case 'C', 'D':
// right, left
mod, _ := strconv.ParseInt(string(num), 10, 32)
if mod != 5 {
// Not bare Ctrl
rv := s.pending[0]
s.pending = s.pending[1:]
return rv, nil
}
s.pending = s.pending[:0] // escape code complete
if code == 'C' {
return wordRight, nil
}
return wordLeft, nil
default:
// Not left or right
rv := s.pending[0]
s.pending = s.pending[1:]
return rv, nil
}
}
case '~':
s.pending = s.pending[:0] // escape code complete
x, _ := strconv.ParseInt(string(num), 10, 32)
switch x {
case 2:
return insert, nil
case 3:
return del, nil
case 5:
return pageUp, nil
case 6:
return pageDown, nil
case 1, 7:
return home, nil
case 4, 8:
return end, nil
case 15:
return f5, nil
case 17:
return f6, nil
case 18:
return f7, nil
case 19:
return f8, nil
case 20:
return f9, nil
case 21:
return f10, nil
case 23:
return f11, nil
case 24:
return f12, nil
default:
return unknown, nil
}
default:
// unrecognized escape code
rv := s.pending[0]
s.pending = s.pending[1:]
return rv, nil
}
}
}
case 'O':
code, err := s.nextPending(timeout)
if err != nil {
if err == errTimedOut {
return code, nil
}
return nil, err
}
s.pending = s.pending[:0] // escape code complete
switch code {
case 'c':
return wordRight, nil
case 'd':
return wordLeft, nil
case 'H':
return home, nil
case 'F':
return end, nil
case 'P':
return f1, nil
case 'Q':
return f2, nil
case 'R':
return f3, nil
case 'S':
return f4, nil
default:
return unknown, nil
}
case 'b':
s.pending = s.pending[:0] // escape code complete
return altB, nil
case 'd':
s.pending = s.pending[:0] // escape code complete
return altD, nil
case bs:
s.pending = s.pending[:0] // escape code complete
return altBs, nil
case 'f':
s.pending = s.pending[:0] // escape code complete
return altF, nil
case 'y':
s.pending = s.pending[:0] // escape code complete
return altY, nil
default:
rv := s.pending[0]
s.pending = s.pending[1:]
return rv, nil
}
// not reached
return r, nil
}
// Close returns the terminal to its previous mode
func (s *State) Close() error {
signal.Stop(s.winch)
if !s.inputRedirected {
s.origMode.ApplyMode()
}
return nil
}
// TerminalSupported returns true if the current terminal supports
// line editing features, and false if liner will use the 'dumb'
// fallback for input.
// Note that TerminalSupported does not check all factors that may
// cause liner to not fully support the terminal (such as stdin redirection)
func TerminalSupported() bool {
bad := map[string]bool{"": true, "dumb": true, "cons25": true}
return !bad[strings.ToLower(os.Getenv("TERM"))]
}
const (
getTermios = syscall.TCGETS
setTermios = syscall.TCSETS
)
const (
icrnl = syscall.ICRNL
inpck = syscall.INPCK
istrip = syscall.ISTRIP
ixon = syscall.IXON
opost = syscall.OPOST
cs8 = syscall.CS8
isig = syscall.ISIG
icanon = syscall.ICANON
iexten = syscall.IEXTEN
)
type termios struct {
syscall.Termios
}
const cursorColumn = false