Create a helper function to get the terminal width

Rationale: contain terminal access to one file.

src/cmds/restic/cmd_backup.go

@@ -10,8 +10,6 @@ import (
 	"strings"
 	"time"
 
-	"golang.org/x/crypto/ssh/terminal"
-
 	"github.com/spf13/cobra"
 
 	"restic/archiver"
@@ -136,8 +134,7 @@ func newArchiveProgress(gopts GlobalOptions, todo restic.Stat) *restic.Progress
 			s.Errors)
 		status2 := fmt.Sprintf("ETA %s ", formatSeconds(eta))
 
-		w, _, err := terminal.GetSize(int(os.Stdout.Fd()))
+		if w := stdoutTerminalWidth(); w > 0 {
-		if err == nil {
 			maxlen := w - len(status2) - 1
 
 			if maxlen < 4 {
@@ -181,8 +178,7 @@ func newArchiveStdinProgress(gopts GlobalOptions) *restic.Progress {
 			formatBytes(s.Bytes),
 			formatBytes(bps))
 
-		w, _, err := terminal.GetSize(int(os.Stdout.Fd()))
+		if w := stdoutTerminalWidth(); w > 0 {
-		if err == nil {
 			maxlen := w - len(status1)
 
 			if maxlen < 4 {

src/cmds/restic/cmd_check.go

@@ -7,8 +7,6 @@ import (
 
 	"github.com/spf13/cobra"
 
-	"golang.org/x/crypto/ssh/terminal"
-
 	"restic"
 	"restic/checker"
 	"restic/errors"
@@ -55,8 +53,7 @@ func newReadProgress(gopts GlobalOptions, todo restic.Stat) *restic.Progress {
 			formatPercent(s.Blobs, todo.Blobs),
 			s.Blobs, todo.Blobs)
 
-		w, _, err := terminal.GetSize(int(os.Stdout.Fd()))
+		if w := stdoutTerminalWidth(); w > 0 {
-		if err == nil {
 			if len(status) > w {
 				max := w - len(status) - 4
 				status = status[:max] + "... "

src/cmds/restic/cmd_prune.go

@@ -11,8 +11,6 @@ import (
 	"time"
 
 	"github.com/spf13/cobra"
-
-	"golang.org/x/crypto/ssh/terminal"
 )
 
 var cmdPrune = &cobra.Command{
@@ -45,8 +43,7 @@ func newProgressMax(show bool, max uint64, description string) *restic.Progress
 			formatPercent(s.Blobs, max),
 			s.Blobs, max, description)
 
-		w, _, err := terminal.GetSize(int(os.Stdout.Fd()))
+		if w := stdoutTerminalWidth(); w > 0 {
-		if err == nil {
 			if len(status) > w {
 				max := w - len(status) - 4
 				status = status[:max] + "... "

src/cmds/restic/global.go

@@ -82,6 +82,14 @@ func stdoutIsTerminal() bool {
 	return terminal.IsTerminal(int(os.Stdout.Fd()))
 }
 
+func stdoutTerminalWidth() int {
+	w, _, err := terminal.GetSize(int(os.Stdout.Fd()))
+	if err != nil {
+		return 0
+	}
+	return w
+}
+
 // restoreTerminal installs a cleanup handler that restores the previous
 // terminal state on exit.
 func restoreTerminal() {
@@ -110,8 +118,7 @@ func restoreTerminal() {
 // current windows cmd shell.
 func ClearLine() string {
 	if runtime.GOOS == "windows" {
-		w, _, err := terminal.GetSize(int(os.Stdout.Fd()))
+		if w := stdoutTerminalWidth(); w > 0 {
-		if err == nil {
 			return strings.Repeat(" ", w-1) + "\r"
 		}
 		return ""