mirror of https://github.com/restic/restic.git
Add termstatus
This commit is contained in:
Alexander Neumann
parent
9fac2ca832
commit
1af96fc6dd
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@ -0,0 +1,281 @@
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package termstatus
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import (
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"bufio"
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"bytes"
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"context"
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"fmt"
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"io"
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"os"
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"strings"
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)
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// Terminal is used to write messages and display status lines which can be
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// updated. When the output is redirected to a file, the status lines are not
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// printed.
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type Terminal struct {
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wr *bufio.Writer
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fd uintptr
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errWriter io.Writer
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buf *bytes.Buffer
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msg chan message
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status chan status
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canUpdateStatus bool
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clearLines clearLinesFunc
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}
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type clearLinesFunc func(wr io.Writer, fd uintptr, n int)
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type message struct {
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line string
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err bool
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}
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type status struct {
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lines []string
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}
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type fder interface {
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Fd() uintptr
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}
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// New returns a new Terminal for wr. A goroutine is started to update the
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// terminal. It is terminated when ctx is cancelled. When wr is redirected to
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// a file (e.g. via shell output redirection) or is just an io.Writer (not the
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// open *os.File for stdout), no status lines are printed. The status lines and
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// normal output (via Print/Printf) are written to wr, error messages are
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// written to errWriter.
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func New(wr io.Writer, errWriter io.Writer) *Terminal {
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t := &Terminal{
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wr: bufio.NewWriter(wr),
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errWriter: errWriter,
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buf: bytes.NewBuffer(nil),
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msg: make(chan message),
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status: make(chan status),
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}
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if d, ok := wr.(fder); ok && canUpdateStatus(d.Fd()) {
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// only use the fancy status code when we're running on a real terminal.
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t.canUpdateStatus = true
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t.fd = d.Fd()
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t.clearLines = clearLines(wr, t.fd)
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}
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return t
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}
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// Run updates the screen. It should be run in a separate goroutine. When
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// ctx is cancelled, the status lines are cleanly removed.
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func (t *Terminal) Run(ctx context.Context) {
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if t.canUpdateStatus {
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t.run(ctx)
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return
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}
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t.runWithoutStatus(ctx)
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}
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func countLines(buf []byte) int {
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lines := 0
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sc := bufio.NewScanner(bytes.NewReader(buf))
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for sc.Scan() {
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lines++
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}
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return lines
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}
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type stringWriter interface {
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WriteString(string) (int, error)
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}
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// run listens on the channels and updates the terminal screen.
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func (t *Terminal) run(ctx context.Context) {
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statusBuf := bytes.NewBuffer(nil)
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statusLines := 0
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for {
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select {
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case <-ctx.Done():
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t.undoStatus(statusLines)
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err := t.wr.Flush()
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if err != nil {
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fmt.Fprintf(os.Stderr, "flush failed: %v\n", err)
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}
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return
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case msg := <-t.msg:
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t.undoStatus(statusLines)
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var dst io.Writer
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if msg.err {
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dst = t.errWriter
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// assume t.wr and t.errWriter are different, so we need to
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// flush the removal of the status lines first.
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err := t.wr.Flush()
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if err != nil {
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fmt.Fprintf(os.Stderr, "flush failed: %v\n", err)
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}
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} else {
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dst = t.wr
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}
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var err error
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if w, ok := dst.(stringWriter); ok {
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_, err = w.WriteString(msg.line)
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} else {
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_, err = dst.Write([]byte(msg.line))
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}
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if err != nil {
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fmt.Fprintf(os.Stderr, "write failed: %v\n", err)
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continue
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}
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_, err = t.wr.Write(statusBuf.Bytes())
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if err != nil {
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fmt.Fprintf(os.Stderr, "write failed: %v\n", err)
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}
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err = t.wr.Flush()
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if err != nil {
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fmt.Fprintf(os.Stderr, "flush failed: %v\n", err)
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}
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case stat := <-t.status:
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t.undoStatus(statusLines)
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statusBuf.Reset()
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for _, line := range stat.lines {
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statusBuf.WriteString(line)
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}
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statusLines = len(stat.lines)
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_, err := t.wr.Write(statusBuf.Bytes())
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if err != nil {
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fmt.Fprintf(os.Stderr, "write failed: %v\n", err)
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}
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err = t.wr.Flush()
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if err != nil {
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fmt.Fprintf(os.Stderr, "flush failed: %v\n", err)
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}
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}
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}
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}
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// runWithoutStatus listens on the channels and just prints out the messages,
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// without status lines.
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func (t *Terminal) runWithoutStatus(ctx context.Context) {
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for {
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select {
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case <-ctx.Done():
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return
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case msg := <-t.msg:
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var err error
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var flush func() error
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var dst io.Writer
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if msg.err {
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dst = t.errWriter
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} else {
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dst = t.wr
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flush = t.wr.Flush
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}
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if w, ok := dst.(stringWriter); ok {
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_, err = w.WriteString(msg.line)
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} else {
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_, err = dst.Write([]byte(msg.line))
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}
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if err != nil {
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fmt.Fprintf(os.Stderr, "write failed: %v\n", err)
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}
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if flush == nil {
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continue
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}
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err = flush()
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if err != nil {
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fmt.Fprintf(os.Stderr, "flush failed: %v\n", err)
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}
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case _ = <-t.status:
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// discard status lines
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}
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}
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}
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func (t *Terminal) undoStatus(lines int) {
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if lines == 0 {
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return
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}
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lines--
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t.clearLines(t.wr, t.fd, lines)
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}
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// Print writes a line to the terminal.
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func (t *Terminal) Print(line string) {
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// make sure the line ends with a line break
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if line[len(line)-1] != '\n' {
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line += "\n"
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}
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t.msg <- message{line: line}
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}
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// Printf uses fmt.Sprintf to write a line to the terminal.
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func (t *Terminal) Printf(msg string, args ...interface{}) {
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s := fmt.Sprintf(msg, args...)
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t.Print(s)
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}
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// Error writes an error to the terminal.
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func (t *Terminal) Error(line string) {
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// make sure the line ends with a line break
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if line[len(line)-1] != '\n' {
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line += "\n"
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}
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t.msg <- message{line: line, err: true}
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}
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// Errorf uses fmt.Sprintf to write an error line to the terminal.
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func (t *Terminal) Errorf(msg string, args ...interface{}) {
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s := fmt.Sprintf(msg, args...)
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t.Error(s)
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}
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// SetStatus updates the status lines.
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func (t *Terminal) SetStatus(lines []string) {
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if len(lines) == 0 {
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return
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}
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width, _, err := getTermSize(t.fd)
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if err != nil || width < 0 {
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// use 80 columns by default
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width = 80
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}
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// make sure that all lines have a line break and are not too long
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for i, line := range lines {
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line = strings.TrimRight(line, "\n")
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if len(line) >= width-2 {
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line = line[:width-2]
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}
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line += "\n"
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lines[i] = line
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}
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// make sure the last line does not have a line break
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last := len(lines) - 1
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lines[last] = strings.TrimRight(lines[last], "\n")
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t.status <- status{lines: lines}
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}
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@ -0,0 +1,33 @@
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package termstatus
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import (
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"fmt"
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"io"
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"os"
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)
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const (
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posixMoveCursorHome = "\r"
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posixMoveCursorUp = "\x1b[1A"
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posixClearLine = "\x1b[2K"
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)
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// posixClearLines will clear the current line and the n lines above.
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// Afterwards the cursor is positioned at the start of the first cleared line.
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func posixClearLines(wr io.Writer, fd uintptr, n int) {
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// clear current line
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_, err := wr.Write([]byte(posixMoveCursorHome + posixClearLine))
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if err != nil {
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fmt.Fprintf(os.Stderr, "write failed: %v\n", err)
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return
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}
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for ; n > 0; n-- {
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// clear current line and move on line up
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_, err := wr.Write([]byte(posixMoveCursorUp + posixClearLine))
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if err != nil {
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fmt.Fprintf(os.Stderr, "write failed: %v\n", err)
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return
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}
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}
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}
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@ -0,0 +1,34 @@
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// +build !windows
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package termstatus
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import (
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"io"
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"syscall"
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"unsafe"
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isatty "github.com/mattn/go-isatty"
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)
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// clearLines will clear the current line and the n lines above. Afterwards the
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// cursor is positioned at the start of the first cleared line.
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func clearLines(wr io.Writer, fd uintptr) clearLinesFunc {
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return posixClearLines
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}
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// canUpdateStatus returns true if status lines can be printed, the process
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// output is not redirected to a file or pipe.
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func canUpdateStatus(fd uintptr) bool {
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return isatty.IsTerminal(fd)
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}
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// getTermSize returns the dimensions of the given terminal.
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// the code is taken from "golang.org/x/crypto/ssh/terminal"
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func getTermSize(fd uintptr) (width, height int, err error) {
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var dimensions [4]uint16
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if _, _, err := syscall.Syscall6(syscall.SYS_IOCTL, fd, uintptr(syscall.TIOCGWINSZ), uintptr(unsafe.Pointer(&dimensions)), 0, 0, 0); err != 0 {
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return -1, -1, err
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}
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return int(dimensions[1]), int(dimensions[0]), nil
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}
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@ -0,0 +1,131 @@
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// +build windows
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package termstatus
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import (
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"io"
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"syscall"
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"unsafe"
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)
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// clearLines clears the current line and n lines above it.
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func clearLines(wr io.Writer, fd uintptr) clearLinesFunc {
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// easy case, the terminal is cmd or psh, without redirection
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if isWindowsTerminal(fd) {
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return windowsClearLines
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}
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// check if the output file type is a pipe (0x0003)
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if getFileType(fd) != fileTypePipe {
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// return empty func, update state is not possible on this terminal
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return func(io.Writer, uintptr, int) {}
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}
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// assume we're running in mintty/cygwin
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return posixClearLines
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}
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var kernel32 = syscall.NewLazyDLL("kernel32.dll")
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var (
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procGetConsoleScreenBufferInfo = kernel32.NewProc("GetConsoleScreenBufferInfo")
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procSetConsoleCursorPosition = kernel32.NewProc("SetConsoleCursorPosition")
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procFillConsoleOutputCharacter = kernel32.NewProc("FillConsoleOutputCharacterW")
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procFillConsoleOutputAttribute = kernel32.NewProc("FillConsoleOutputAttribute")
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procGetConsoleMode = kernel32.NewProc("GetConsoleMode")
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procGetFileType = kernel32.NewProc("GetFileType")
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)
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type (
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short int16
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word uint16
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dword uint32
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coord struct {
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x short
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y short
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}
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smallRect struct {
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left short
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top short
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right short
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bottom short
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}
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consoleScreenBufferInfo struct {
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size coord
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cursorPosition coord
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attributes word
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window smallRect
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maximumWindowSize coord
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}
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)
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// windowsClearLines clears the current line and n lines above it.
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func windowsClearLines(wr io.Writer, fd uintptr, n int) {
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var info consoleScreenBufferInfo
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procGetConsoleScreenBufferInfo.Call(fd, uintptr(unsafe.Pointer(&info)))
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for i := 0; i <= n; i++ {
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// clear the line
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cursor := coord{
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x: info.window.left,
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y: info.cursorPosition.y - short(i),
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}
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var count, w dword
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count = dword(info.size.x)
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procFillConsoleOutputAttribute.Call(fd, uintptr(info.attributes), uintptr(count), *(*uintptr)(unsafe.Pointer(&cursor)), uintptr(unsafe.Pointer(&w)))
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procFillConsoleOutputCharacter.Call(fd, uintptr(' '), uintptr(count), *(*uintptr)(unsafe.Pointer(&cursor)), uintptr(unsafe.Pointer(&w)))
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}
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// move cursor up by n lines and to the first column
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info.cursorPosition.y -= short(n)
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info.cursorPosition.x = 0
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procSetConsoleCursorPosition.Call(fd, uintptr(*(*int32)(unsafe.Pointer(&info.cursorPosition))))
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}
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// getTermSize returns the dimensions of the given terminal.
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// the code is taken from "golang.org/x/crypto/ssh/terminal"
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func getTermSize(fd uintptr) (width, height int, err error) {
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var info consoleScreenBufferInfo
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_, _, e := syscall.Syscall(procGetConsoleScreenBufferInfo.Addr(), 2, fd, uintptr(unsafe.Pointer(&info)), 0)
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if e != 0 {
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return 0, 0, error(e)
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}
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return int(info.size.x), int(info.size.y), nil
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}
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// isWindowsTerminal return true if the file descriptor is a windows terminal (cmd, psh).
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func isWindowsTerminal(fd uintptr) bool {
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var st uint32
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r, _, e := syscall.Syscall(procGetConsoleMode.Addr(), 2, fd, uintptr(unsafe.Pointer(&st)), 0)
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return r != 0 && e == 0
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}
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const fileTypePipe = 0x0003
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// getFileType returns the file type for the given fd.
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// https://msdn.microsoft.com/de-de/library/windows/desktop/aa364960(v=vs.85).aspx
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func getFileType(fd uintptr) int {
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r, _, e := syscall.Syscall(procGetFileType.Addr(), 1, fd, 0, 0)
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if e != 0 {
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return 0
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}
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return int(r)
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}
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// canUpdateStatus returns true if status lines can be printed, the process
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// output is not redirected to a file or pipe.
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func canUpdateStatus(fd uintptr) bool {
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// easy case, the terminal is cmd or psh, without redirection
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if isWindowsTerminal(fd) {
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return true
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}
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// check if the output file type is a pipe (0x0003)
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if getFileType(fd) != fileTypePipe {
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return false
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}
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// assume we're running in mintty/cygwin
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return true
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}
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