Fix progress output on Windows

The windows cmd shell is not aware of ANSI escape sequences and
does print them uninterpreted to the console. This is ugly.
Added a function to generate platform specific string for the escape sequence. On Windows this will be 79 white spaces with
a trailing \r.

src/cmds/restic/cleanup.go

@@ -57,7 +57,7 @@ func RunCleanupHandlers() {
 func CleanupHandler(c <-chan os.Signal) {
 	for s := range c {
 		debug.Log("CleanupHandler", "signal %v received, cleaning up", s)
-		fmt.Println("\x1b[2KInterrupt received, cleaning up")
+		fmt.Printf("%sInterrupt received, cleaning up\n", ClearLine())
 		RunCleanupHandlers()
 		fmt.Println("exiting")
 		os.Exit(0)

src/cmds/restic/cmd_backup.go

@@ -114,10 +114,10 @@ func (cmd CmdBackup) newScanProgress() *restic.Progress {
 
 	p := restic.NewProgress(time.Second)
 	p.OnUpdate = func(s restic.Stat, d time.Duration, ticker bool) {
-		fmt.Printf("\x1b[2K[%s] %d directories, %d files, %s\r", formatDuration(d), s.Dirs, s.Files, formatBytes(s.Bytes))
+		fmt.Printf("%s[%s] %d directories, %d files, %s\r", ClearLine(), formatDuration(d), s.Dirs, s.Files, formatBytes(s.Bytes))
 	}
 	p.OnDone = func(s restic.Stat, d time.Duration, ticker bool) {
-		fmt.Printf("\x1b[2Kscanned %d directories, %d files in %s\n", s.Dirs, s.Files, formatDuration(d))
+		fmt.Printf("%sscanned %d directories, %d files in %s\n", ClearLine(), s.Dirs, s.Files, formatDuration(d))
 	}
 
 	return p
@@ -167,7 +167,7 @@ func (cmd CmdBackup) newArchiveProgress(todo restic.Stat) *restic.Progress {
 			}
 		}
 
-		fmt.Printf("\x1b[2K%s%s\r", status1, status2)
+		fmt.Printf("%s%s%s\r", ClearLine(), status1, status2)
 	}
 
 	archiveProgress.OnDone = func(s restic.Stat, d time.Duration, ticker bool) {
@@ -208,7 +208,7 @@ func (cmd CmdBackup) newArchiveStdinProgress() *restic.Progress {
 			}
 		}
 
-		fmt.Printf("\x1b[2K%s\r", status1)
+		fmt.Printf("%s%s\r", ClearLine(), status1)
 	}
 
 	archiveProgress.OnDone = func(s restic.Stat, d time.Duration, ticker bool) {
@@ -375,7 +375,7 @@ func (cmd CmdBackup) Execute(args []string) error {
 
 	arch.Error = func(dir string, fi os.FileInfo, err error) error {
 		// TODO: make ignoring errors configurable
-		cmd.global.Warnf("\x1b[2K\rerror for %s: %v\n", dir, err)
+		cmd.global.Warnf("%s\rerror for %s: %v\n", ClearLine(), dir, err)
 		return nil
 	}
 

src/cmds/restic/cmd_check.go

@@ -54,7 +54,7 @@ func (cmd CmdCheck) newReadProgress(todo restic.Stat) *restic.Progress {
 			}
 		}
 
-		fmt.Printf("\x1b[2K%s\r", status)
+		fmt.Printf("%s%s\r", ClearLine(), status)
 	}
 
 	readProgress.OnDone = func(s restic.Stat, d time.Duration, ticker bool) {

src/cmds/restic/cmd_prune.go

@@ -55,7 +55,7 @@ func newProgressMax(show bool, max uint64, description string) *restic.Progress
 			}
 		}
 
-		fmt.Printf("\x1b[2K%s\r", status)
+		fmt.Printf("%s%s\r", ClearLine(), status)
 	}
 
 	p.OnDone = func(s restic.Stat, d time.Duration, ticker bool) {

src/cmds/restic/global.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"io"
 	"os"
+	"runtime"
 	"strings"
 	"syscall"
 
@@ -82,6 +83,16 @@ func restoreTerminal() {
 var globalOpts = GlobalOptions{stdout: os.Stdout, stderr: os.Stderr}
 var parser = flags.NewParser(&globalOpts, flags.HelpFlag|flags.PassDoubleDash)
 
+// Clear Line ASCII sequence is invalid on Windows so ignore it here
+func ClearLine() string {
+	if runtime.GOOS == "windows" {
+		// Ugly Workaround, write 79 Whitespaces and return
+		return "                                                                               \r"
+	} else {
+		return "\x1b[2K"
+	}
+}
+
 // Printf writes the message to the configured stdout stream.
 func (o GlobalOptions) Printf(format string, args ...interface{}) {
 	_, err := fmt.Fprintf(o.stdout, format, args...)