configmap: Add Encode and Decode methods to Simple for command line e…

…ncoding rclone#5178

fs/config/configmap/configmap.go

@@ -2,8 +2,13 @@
 package configmap
 
 import (
+	"encoding/base64"
+	"encoding/json"
 	"sort"
 	"strings"
+	"unicode"
+
+	"github.com/pkg/errors"
 )
 
 // Priority of getters
@@ -159,3 +164,38 @@ func (c Simple) String() string {
 	}
 	return out.String()
 }
+
+// Encode from c into a string suitable for putting on the command line
+func (c Simple) Encode() (string, error) {
+	if len(c) == 0 {
+		return "", nil
+	}
+	buf, err := json.Marshal(c)
+	if err != nil {
+		return "", errors.Wrap(err, "encode simple map")
+	}
+	return base64.RawStdEncoding.EncodeToString(buf), nil
+}
+
+// Decode an Encode~d string in into c
+func (c Simple) Decode(in string) error {
+	// Remove all whitespace from the input string
+	in = strings.Map(func(r rune) rune {
+		if unicode.IsSpace(r) {
+			return -1
+		}
+		return r
+	}, in)
+	if len(in) == 0 {
+		return nil
+	}
+	decodedM, err := base64.RawStdEncoding.DecodeString(in)
+	if err != nil {
+		return errors.Wrap(err, "decode simple map")
+	}
+	err = json.Unmarshal(decodedM, &c)
+	if err != nil {
+		return errors.Wrap(err, "parse simple map")
+	}
+	return nil
+}

fs/config/configmap/configmap_test.go

@@ -1,9 +1,11 @@
 package configmap
 
 import (
+	"encoding/base64"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 var (
@@ -267,3 +269,91 @@ func TestSimpleString(t *testing.T) {
 		"apple":   "",
 	}.String())
 }
+
+func TestSimpleEncode(t *testing.T) {
+	for _, test := range []struct {
+		in   Simple
+		want string
+	}{
+		{
+			in:   Simple{},
+			want: "",
+		},
+		{
+			in: Simple{
+				"one": "potato",
+			},
+			want: "eyJvbmUiOiJwb3RhdG8ifQ",
+		},
+		{
+			in: Simple{
+				"one": "potato",
+				"two": "",
+			},
+			want: "eyJvbmUiOiJwb3RhdG8iLCJ0d28iOiIifQ",
+		},
+	} {
+		got, err := test.in.Encode()
+		require.NoError(t, err)
+		assert.Equal(t, test.want, got)
+		gotM := Simple{}
+		err = gotM.Decode(got)
+		require.NoError(t, err)
+		assert.Equal(t, test.in, gotM)
+	}
+}
+
+func TestSimpleDecode(t *testing.T) {
+	for _, test := range []struct {
+		in      string
+		want    Simple
+		wantErr string
+	}{
+		{
+			in:   "",
+			want: Simple{},
+		},
+		{
+			in: "eyJvbmUiOiJwb3RhdG8ifQ",
+			want: Simple{
+				"one": "potato",
+			},
+		},
+		{
+			in: "   e yJvbm  UiOiJwb\r\n 3Rhd\tG8ifQ\n\n ",
+			want: Simple{
+				"one": "potato",
+			},
+		},
+		{
+			in: "eyJvbmUiOiJwb3RhdG8iLCJ0d28iOiIifQ",
+			want: Simple{
+				"one": "potato",
+				"two": "",
+			},
+		},
+		{
+			in:      "!!!!!",
+			want:    Simple{},
+			wantErr: "decode simple map",
+		},
+		{
+			in:   base64.RawStdEncoding.EncodeToString([]byte(`null`)),
+			want: Simple{},
+		},
+		{
+			in:      base64.RawStdEncoding.EncodeToString([]byte(`rubbish`)),
+			want:    Simple{},
+			wantErr: "parse simple map",
+		},
+	} {
+		got := Simple{}
+		err := got.Decode(test.in)
+		assert.Equal(t, test.want, got, test.in)
+		if test.wantErr == "" {
+			require.NoError(t, err, test.in)
+		} else {
+			assert.Contains(t, err.Error(), test.wantErr, test.in)
+		}
+	}
+}