Refactor CLI docker save

Signed-off-by: Hu Keping <hukeping@huawei.com>

api/client/cli.go

@@ -52,7 +52,7 @@ type DockerCli struct {
 	outFd uintptr
 	// isTerminalIn indicates whether the client's STDIN is a TTY
 	isTerminalIn bool
-	// isTerminalOut dindicates whether the client's STDOUT is a TTY
+	// isTerminalOut indicates whether the client's STDOUT is a TTY
 	isTerminalOut bool
 	// transport holds the client transport instance.
 	transport *http.Transport

api/client/save.go

@@ -25,13 +25,14 @@ func (cli *DockerCli) CmdSave(args ...string) error {
 		output = cli.out
 		err    error
 	)
+
+	if *outfile == "" && cli.isTerminalOut {
+		return errors.New("Cowardly refusing to save to a terminal. Use the -o flag or redirect.")
+	}
 	if *outfile != "" {
-		output, err = os.Create(*outfile)
-		if err != nil {
+		if output, err = os.Create(*outfile); err != nil {
 			return err
 		}
-	} else if cli.isTerminalOut {
-		return errors.New("Cowardly refusing to save to a terminal. Use the -o flag or redirect.")
 	}
 
 	sopts := &streamOpts{
@@ -39,19 +40,13 @@ func (cli *DockerCli) CmdSave(args ...string) error {
 		out:         output,
 	}
 
-	if len(cmd.Args()) == 1 {
-		image := cmd.Arg(0)
-		if _, err := cli.stream("GET", "/images/"+image+"/get", sopts); err != nil {
-			return err
-		}
-	} else {
-		v := url.Values{}
-		for _, arg := range cmd.Args() {
-			v.Add("names", arg)
-		}
-		if _, err := cli.stream("GET", "/images/get?"+v.Encode(), sopts); err != nil {
-			return err
-		}
+	v := url.Values{}
+	for _, arg := range cmd.Args() {
+		v.Add("names", arg)
 	}
+	if _, err := cli.stream("GET", "/images/get?"+v.Encode(), sopts); err != nil {
+		return err
+	}
+
 	return nil
 }