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package cwriter
import (
"bytes"
"errors"
"fmt"
"io"
"os"
"golang.org/x/crypto/ssh/terminal"
)
// NotATTY not a TeleTYpewriter error.
var NotATTY = errors.New("not a terminal")
var cuuAndEd = fmt.Sprintf("%c[%%dA%[1]c[J", 27)
// Writer is a buffered the writer that updates the terminal. The
// contents of writer will be flushed when Flush is called.
type Writer struct {
out io.Writer
buf bytes.Buffer
lineCount int
fd uintptr
isTerminal bool
}
// New returns a new Writer with defaults.
func New(out io.Writer) *Writer {
w := &Writer{out: out}
if f, ok := out.(*os.File); ok {
w.fd = f.Fd()
w.isTerminal = terminal.IsTerminal(int(w.fd))
}
return w
}
// Flush flushes the underlying buffer.
func (w *Writer) Flush(lineCount int) (err error) {
if w.lineCount > 0 {
w.clearLines()
}
w.lineCount = lineCount
_, err = w.buf.WriteTo(w.out)
return
}
// Write appends the contents of p to the underlying buffer.
func (w *Writer) Write(p []byte) (n int, err error) {
return w.buf.Write(p)
}
// WriteString writes string to the underlying buffer.
func (w *Writer) WriteString(s string) (n int, err error) {
return w.buf.WriteString(s)
}
// ReadFrom reads from the provided io.Reader and writes to the
// underlying buffer.
func (w *Writer) ReadFrom(r io.Reader) (n int64, err error) {
return w.buf.ReadFrom(r)
}
// GetWidth returns width of underlying terminal.
func (w *Writer) GetWidth() (int, error) {
if w.isTerminal {
tw, _, err := terminal.GetSize(int(w.fd))
return tw, err
}
return -1, NotATTY
}
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