/
term.go
217 lines (183 loc) 路 3.69 KB
/
term.go
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package terminal
import (
"bytes"
"errors"
"fmt"
"io"
"os"
"github.com/muesli/cancelreader"
"golang.org/x/term"
)
type Terminal interface {
io.WriteCloser
IsRaw() bool
Size() (width, height int, err error)
ClearLine()
ClearEnd()
CursorUp(count int)
CursorDown(count int)
HideCursor()
ShowCursor()
ReadKey() (string, error)
}
var ErrNotATerminal = errors.New("not a terminal")
type terminal struct {
fd int
info Info
raw bool
save *term.State
out io.Writer
in cancelreader.CancelReader
}
func Open(in io.Reader, out io.Writer, raw bool) (Terminal, error) {
type fileLike interface {
Fd() uintptr
}
outFile, ok := out.(fileLike)
if !ok {
return nil, ErrNotATerminal
}
outFd := int(outFile.Fd())
width, height, err := term.GetSize(outFd)
if err != nil {
return nil, fmt.Errorf("getting dimensions: %w", err)
}
if width == 0 || height == 0 {
return nil, fmt.Errorf("unusable dimensions (%v x %v)", width, height)
}
termType := os.Getenv("TERM")
if termType == "" {
termType = "vt102"
}
info := OpenInfo(termType)
var save *term.State
var inFile cancelreader.CancelReader
if raw {
if save, err = term.MakeRaw(outFd); err != nil {
return nil, fmt.Errorf("enabling raw mode: %w", err)
}
if inFile, err = cancelreader.NewReader(in); err != nil {
return nil, ErrNotATerminal
}
}
return &terminal{
fd: outFd,
info: info,
raw: raw,
save: save,
out: out,
in: inFile,
}, nil
}
func (t *terminal) IsRaw() bool {
return t.raw
}
func (t *terminal) Close() error {
t.in.Cancel()
if t.save != nil {
return term.Restore(t.fd, t.save)
}
return nil
}
func (t *terminal) Size() (width, height int, err error) {
return term.GetSize(t.fd)
}
func (t *terminal) Write(b []byte) (int, error) {
if !t.raw {
return t.out.Write(b)
}
written := 0
for {
newline := bytes.IndexByte(b, '\n')
if newline == -1 {
w, err := t.out.Write(b)
written += w
return written, err
}
w, err := t.out.Write(b[:newline])
written += w
if err != nil {
return written, err
}
if _, err = t.out.Write([]byte{'\r', '\n'}); err != nil {
return written, err
}
written++
b = b[newline+1:]
}
}
func (t *terminal) ClearLine() {
t.info.ClearLine(t.out)
}
func (t *terminal) ClearEnd() {
t.info.ClearEnd(t.out)
}
func (t *terminal) CursorUp(count int) {
t.info.CursorUp(t.out, count)
}
func (t *terminal) CursorDown(count int) {
t.info.CursorDown(t.out, count)
}
func (t *terminal) HideCursor() {
t.info.HideCursor(t.out)
}
func (t *terminal) ShowCursor() {
t.info.ShowCursor(t.out)
}
func (t *terminal) ReadKey() (string, error) {
if t.in == nil {
return "", io.EOF
}
type stateFunc func(b byte) (stateFunc, string)
var stateIntermediate stateFunc
stateIntermediate = func(b byte) (stateFunc, string) {
if b >= 0x20 && b < 0x30 {
return stateIntermediate, ""
}
switch b {
case 'A':
return nil, "up"
case 'B':
return nil, "down"
default:
return nil, "<control>"
}
}
var stateParameter stateFunc
stateParameter = func(b byte) (stateFunc, string) {
if b >= 0x30 && b < 0x40 {
return stateParameter, ""
}
return stateIntermediate(b)
}
stateBracket := func(b byte) (stateFunc, string) {
if b == '[' {
return stateParameter, ""
}
return nil, "<control>"
}
stateEscape := func(b byte) (stateFunc, string) {
if b == 0x1b {
return stateBracket, ""
}
if b == 3 {
return nil, "ctrl+c"
}
return nil, string([]byte{b})
}
state := stateEscape
for {
var b [1]byte
if _, err := t.in.Read(b[:]); err != nil {
if errors.Is(err, cancelreader.ErrCanceled) {
err = io.EOF
}
return "", err
}
next, key := state(b[0])
if next == nil {
return key, nil
}
state = next
}
}