forked from OSchip/llvm-project
363 lines
7.8 KiB
Go
363 lines
7.8 KiB
Go
// +build linux darwin openbsd freebsd netbsd
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package liner
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import (
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"bufio"
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"errors"
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"os"
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"os/signal"
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"strconv"
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"strings"
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"syscall"
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"time"
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)
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type nexter struct {
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r rune
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err error
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}
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// State represents an open terminal
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type State struct {
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commonState
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origMode termios
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defaultMode termios
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next <-chan nexter
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winch chan os.Signal
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pending []rune
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useCHA bool
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}
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// NewLiner initializes a new *State, and sets the terminal into raw mode. To
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// restore the terminal to its previous state, call State.Close().
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//
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// Note if you are still using Go 1.0: NewLiner handles SIGWINCH, so it will
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// leak a channel every time you call it. Therefore, it is recommened that you
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// upgrade to a newer release of Go, or ensure that NewLiner is only called
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// once.
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func NewLiner() *State {
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var s State
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s.r = bufio.NewReader(os.Stdin)
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s.terminalSupported = TerminalSupported()
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if m, err := TerminalMode(); err == nil {
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s.origMode = *m.(*termios)
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} else {
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s.inputRedirected = true
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}
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if _, err := getMode(syscall.Stdout); err != 0 {
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s.outputRedirected = true
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}
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if s.inputRedirected && s.outputRedirected {
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s.terminalSupported = false
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}
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if s.terminalSupported && !s.inputRedirected && !s.outputRedirected {
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mode := s.origMode
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mode.Iflag &^= icrnl | inpck | istrip | ixon
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mode.Cflag |= cs8
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mode.Lflag &^= syscall.ECHO | icanon | iexten
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mode.ApplyMode()
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winch := make(chan os.Signal, 1)
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signal.Notify(winch, syscall.SIGWINCH)
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s.winch = winch
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s.checkOutput()
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}
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if !s.outputRedirected {
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s.getColumns()
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s.outputRedirected = s.columns <= 0
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}
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return &s
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}
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var errTimedOut = errors.New("timeout")
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func (s *State) startPrompt() {
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if s.terminalSupported {
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if m, err := TerminalMode(); err == nil {
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s.defaultMode = *m.(*termios)
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mode := s.defaultMode
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mode.Lflag &^= isig
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mode.ApplyMode()
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}
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}
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s.restartPrompt()
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}
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func (s *State) restartPrompt() {
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next := make(chan nexter)
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go func() {
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for {
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var n nexter
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n.r, _, n.err = s.r.ReadRune()
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next <- n
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// Shut down nexter loop when an end condition has been reached
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if n.err != nil || n.r == '\n' || n.r == '\r' || n.r == ctrlC || n.r == ctrlD {
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close(next)
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return
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}
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}
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}()
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s.next = next
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}
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func (s *State) stopPrompt() {
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if s.terminalSupported {
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s.defaultMode.ApplyMode()
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}
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}
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func (s *State) nextPending(timeout <-chan time.Time) (rune, error) {
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select {
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case thing, ok := <-s.next:
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if !ok {
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return 0, errors.New("liner: internal error")
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}
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if thing.err != nil {
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return 0, thing.err
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}
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s.pending = append(s.pending, thing.r)
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return thing.r, nil
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case <-timeout:
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rv := s.pending[0]
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s.pending = s.pending[1:]
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return rv, errTimedOut
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}
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// not reached
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return 0, nil
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}
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func (s *State) readNext() (interface{}, error) {
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if len(s.pending) > 0 {
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rv := s.pending[0]
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s.pending = s.pending[1:]
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return rv, nil
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}
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var r rune
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select {
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case thing, ok := <-s.next:
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if !ok {
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return 0, errors.New("liner: internal error")
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}
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if thing.err != nil {
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return nil, thing.err
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}
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r = thing.r
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case <-s.winch:
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s.getColumns()
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return winch, nil
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}
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if r != esc {
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return r, nil
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}
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s.pending = append(s.pending, r)
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// Wait at most 50 ms for the rest of the escape sequence
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// If nothing else arrives, it was an actual press of the esc key
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timeout := time.After(50 * time.Millisecond)
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flag, err := s.nextPending(timeout)
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if err != nil {
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if err == errTimedOut {
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return flag, nil
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}
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return unknown, err
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}
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switch flag {
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case '[':
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code, err := s.nextPending(timeout)
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if err != nil {
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if err == errTimedOut {
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return code, nil
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}
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return unknown, err
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}
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switch code {
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case 'A':
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s.pending = s.pending[:0] // escape code complete
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return up, nil
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case 'B':
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s.pending = s.pending[:0] // escape code complete
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return down, nil
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case 'C':
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s.pending = s.pending[:0] // escape code complete
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return right, nil
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case 'D':
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s.pending = s.pending[:0] // escape code complete
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return left, nil
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case 'F':
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s.pending = s.pending[:0] // escape code complete
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return end, nil
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case 'H':
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s.pending = s.pending[:0] // escape code complete
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return home, nil
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case 'Z':
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s.pending = s.pending[:0] // escape code complete
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return shiftTab, nil
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case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
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num := []rune{code}
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for {
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code, err := s.nextPending(timeout)
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if err != nil {
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if err == errTimedOut {
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return code, nil
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}
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return nil, err
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}
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switch code {
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case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
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num = append(num, code)
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case ';':
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// Modifier code to follow
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// This only supports Ctrl-left and Ctrl-right for now
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x, _ := strconv.ParseInt(string(num), 10, 32)
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if x != 1 {
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// Can't be left or right
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rv := s.pending[0]
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s.pending = s.pending[1:]
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return rv, nil
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}
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num = num[:0]
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for {
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code, err = s.nextPending(timeout)
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if err != nil {
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if err == errTimedOut {
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rv := s.pending[0]
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s.pending = s.pending[1:]
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return rv, nil
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}
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return nil, err
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}
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switch code {
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case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
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num = append(num, code)
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case 'C', 'D':
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// right, left
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mod, _ := strconv.ParseInt(string(num), 10, 32)
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if mod != 5 {
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// Not bare Ctrl
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rv := s.pending[0]
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s.pending = s.pending[1:]
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return rv, nil
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}
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s.pending = s.pending[:0] // escape code complete
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if code == 'C' {
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return wordRight, nil
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}
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return wordLeft, nil
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default:
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// Not left or right
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rv := s.pending[0]
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s.pending = s.pending[1:]
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return rv, nil
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}
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}
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case '~':
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s.pending = s.pending[:0] // escape code complete
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x, _ := strconv.ParseInt(string(num), 10, 32)
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switch x {
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case 2:
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return insert, nil
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case 3:
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return del, nil
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case 5:
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return pageUp, nil
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case 6:
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return pageDown, nil
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case 7:
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return home, nil
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case 8:
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return end, nil
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case 15:
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return f5, nil
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case 17:
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return f6, nil
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case 18:
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return f7, nil
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case 19:
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return f8, nil
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case 20:
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return f9, nil
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case 21:
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return f10, nil
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case 23:
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return f11, nil
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case 24:
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return f12, nil
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default:
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return unknown, nil
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}
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default:
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// unrecognized escape code
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rv := s.pending[0]
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s.pending = s.pending[1:]
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return rv, nil
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}
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}
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}
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case 'O':
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code, err := s.nextPending(timeout)
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if err != nil {
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if err == errTimedOut {
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return code, nil
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}
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return nil, err
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}
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s.pending = s.pending[:0] // escape code complete
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switch code {
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case 'c':
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return wordRight, nil
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case 'd':
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return wordLeft, nil
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case 'H':
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return home, nil
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case 'F':
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return end, nil
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case 'P':
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return f1, nil
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case 'Q':
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return f2, nil
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case 'R':
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return f3, nil
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case 'S':
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return f4, nil
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default:
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return unknown, nil
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}
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case 'y':
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s.pending = s.pending[:0] // escape code complete
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return altY, nil
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default:
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rv := s.pending[0]
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s.pending = s.pending[1:]
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return rv, nil
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}
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// not reached
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return r, nil
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}
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// Close returns the terminal to its previous mode
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func (s *State) Close() error {
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stopSignal(s.winch)
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if !s.inputRedirected {
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s.origMode.ApplyMode()
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}
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return nil
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}
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// TerminalSupported returns true if the current terminal supports
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// line editing features, and false if liner will use the 'dumb'
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// fallback for input.
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// Note that TerminalSupported does not check all factors that may
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// cause liner to not fully support the terminal (such as stdin redirection)
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func TerminalSupported() bool {
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bad := map[string]bool{"": true, "dumb": true, "cons25": true}
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return !bad[strings.ToLower(os.Getenv("TERM"))]
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}
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