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restic/internal/ui/stdio_wrapper.go
greatroar 35419de232 Simplify ui.StdioWrapper.Write
Instead of looping to find line breaks, make it look for the last one.
2020-10-17 20:30:46 +02:00

73 lines
1.6 KiB
Go

package ui
import (
"bytes"
"io"
"github.com/restic/restic/internal/ui/termstatus"
)
// StdioWrapper provides stdout and stderr integration with termstatus.
type StdioWrapper struct {
stdout *lineWriter
stderr *lineWriter
}
// NewStdioWrapper initializes a new stdio wrapper that can be used in place of
// os.Stdout or os.Stderr.
func NewStdioWrapper(term *termstatus.Terminal) *StdioWrapper {
return &StdioWrapper{
stdout: newLineWriter(term.Print),
stderr: newLineWriter(term.Error),
}
}
// Stdout returns a writer that is line buffered and can be used in place of
// os.Stdout. On Close(), the remaining bytes are written, followed by a line
// break.
func (w *StdioWrapper) Stdout() io.WriteCloser {
return w.stdout
}
// Stderr returns a writer that is line buffered and can be used in place of
// os.Stderr. On Close(), the remaining bytes are written, followed by a line
// break.
func (w *StdioWrapper) Stderr() io.WriteCloser {
return w.stderr
}
type lineWriter struct {
buf *bytes.Buffer
print func(string)
}
var _ io.WriteCloser = &lineWriter{}
func newLineWriter(print func(string)) *lineWriter {
return &lineWriter{buf: bytes.NewBuffer(nil), print: print}
}
func (w *lineWriter) Write(data []byte) (n int, err error) {
n, err = w.buf.Write(data)
if err != nil {
return n, err
}
// look for line breaks
buf := w.buf.Bytes()
i := bytes.LastIndexByte(buf, '\n')
if i != -1 {
w.print(string(buf[:i+1]))
w.buf.Next(i + 1)
}
return n, err
}
func (w *lineWriter) Close() error {
if w.buf.Len() > 0 {
w.print(string(append(w.buf.Bytes(), '\n')))
}
return nil
}