forked from toolshed/abra
133 lines
3.3 KiB
Go
133 lines
3.3 KiB
Go
//go:build !windows
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// +build !windows
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// The terminal mode manipulation code is derived heavily from:
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// https://github.com/golang/crypto/blob/master/ssh/terminal/util.go:
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// Copyright 2011 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package terminal
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import (
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"bufio"
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"bytes"
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"fmt"
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"syscall"
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"unsafe"
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)
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const (
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normalKeypad = '['
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applicationKeypad = 'O'
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)
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type runeReaderState struct {
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term syscall.Termios
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reader *bufio.Reader
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buf *bytes.Buffer
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}
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func newRuneReaderState(input FileReader) runeReaderState {
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buf := new(bytes.Buffer)
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return runeReaderState{
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reader: bufio.NewReader(&BufferedReader{
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In: input,
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Buffer: buf,
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}),
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buf: buf,
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}
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}
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func (rr *RuneReader) Buffer() *bytes.Buffer {
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return rr.state.buf
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}
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// For reading runes we just want to disable echo.
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func (rr *RuneReader) SetTermMode() error {
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if _, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(rr.stdio.In.Fd()), ioctlReadTermios, uintptr(unsafe.Pointer(&rr.state.term)), 0, 0, 0); err != 0 {
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return err
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}
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newState := rr.state.term
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newState.Lflag &^= syscall.ECHO | syscall.ECHONL | syscall.ICANON | syscall.ISIG
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// Because we are clearing canonical mode, we need to ensure VMIN & VTIME are
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// set to the values we expect. This combination puts things in standard
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// "blocking read" mode (see termios(3)).
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newState.Cc[syscall.VMIN] = 1
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newState.Cc[syscall.VTIME] = 0
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if _, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(rr.stdio.In.Fd()), ioctlWriteTermios, uintptr(unsafe.Pointer(&newState)), 0, 0, 0); err != 0 {
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return err
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}
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return nil
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}
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func (rr *RuneReader) RestoreTermMode() error {
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if _, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(rr.stdio.In.Fd()), ioctlWriteTermios, uintptr(unsafe.Pointer(&rr.state.term)), 0, 0, 0); err != 0 {
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return err
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}
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return nil
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}
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// ReadRune Parse escape sequences such as ESC [ A for arrow keys.
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// See https://vt100.net/docs/vt102-ug/appendixc.html
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func (rr *RuneReader) ReadRune() (rune, int, error) {
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r, size, err := rr.state.reader.ReadRune()
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if err != nil {
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return r, size, err
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}
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if r != KeyEscape {
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return r, size, err
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}
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if rr.state.reader.Buffered() == 0 {
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// no more characters so must be `Esc` key
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return KeyEscape, 1, nil
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}
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r, size, err = rr.state.reader.ReadRune()
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if err != nil {
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return r, size, err
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}
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// ESC O ... or ESC [ ...?
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if r != normalKeypad && r != applicationKeypad {
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return r, size, fmt.Errorf("unexpected escape sequence from terminal: %q", []rune{KeyEscape, r})
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}
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keypad := r
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r, size, err = rr.state.reader.ReadRune()
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if err != nil {
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return r, size, err
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}
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switch r {
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case 'A': // ESC [ A or ESC O A
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return KeyArrowUp, 1, nil
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case 'B': // ESC [ B or ESC O B
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return KeyArrowDown, 1, nil
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case 'C': // ESC [ C or ESC O C
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return KeyArrowRight, 1, nil
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case 'D': // ESC [ D or ESC O D
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return KeyArrowLeft, 1, nil
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case 'F': // ESC [ F or ESC O F
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return SpecialKeyEnd, 1, nil
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case 'H': // ESC [ H or ESC O H
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return SpecialKeyHome, 1, nil
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case '3': // ESC [ 3
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if keypad == normalKeypad {
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// discard the following '~' key from buffer
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_, _ = rr.state.reader.Discard(1)
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return SpecialKeyDelete, 1, nil
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}
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}
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// discard the following '~' key from buffer
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_, _ = rr.state.reader.Discard(1)
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return IgnoreKey, 1, nil
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}
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