Add decoding option to specific how to decode tag 0 or 1 into any

Adds a decoding option to specify how to decode CBOR tag 0 or 1 data item into an empty interface. Based on the specified mode, Unmarshal can return a time.Time value or a time string in a specific format. Signed-off-by: Suriyan Subbarayan [email protected]
fxamacker · Mar 30, 2024 · 219a19c · 219a19c
1 parent a35fe34
commit 219a19c
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Showing 2 changed files with 144 additions and 1 deletion.
diff --git a/decode.go b/decode.go
@@ -472,6 +472,30 @@ func (uttam UnrecognizedTagToAnyMode) valid() bool {
 	return uttam >= 0 && uttam < maxUnrecognizedTagToAny
 }
 
+// TimeTagToAnyMode specifies how to decode CBOR tag 0 and 1 into an empty interface (any).
+// Based on the specified mode, Unmarshal can return a time.Time value or a time string in a specific format.
+type TimeTagToAnyMode int
+
+const (
+	// TimeTagToTime decodes CBOR tag 0 and 1 into a time.Time value
+	// when decoding tag 0 or 1 into an empty interface.
+	TimeTagToTime TimeTagToAnyMode = iota
+
+	// TimeTagToRFC3339 decodes CBOR tag 0 and 1 into a time string in RFC3339 format
+	// when decoding tag 0 or 1 into an empty interface.
+	TimeTagToRFC3339
+
+	// TimeTagToRFC3339Nano decodes CBOR tag 0 and 1 into a time string in RFC3339Nano format
+	// when decoding tag 0 or 1 into an empty interface.
+	TimeTagToRFC3339Nano
+
+	maxTimeTagToAnyMode
+)
+
+func (tttam TimeTagToAnyMode) valid() bool {
+	return tttam >= 0 && tttam < maxTimeTagToAnyMode
+}
+
 // DecOptions specifies decoding options.
 type DecOptions struct {
 	// DupMapKey specifies whether to enforce duplicate map key.
@@ -564,6 +588,10 @@ type DecOptions struct {
 	// UnrecognizedTagToAny specifies how to decode unrecognized CBOR tag into an empty interface.
 	// Currently, recognized CBOR tag numbers are 0, 1, 2, 3, or registered by TagSet.
 	UnrecognizedTagToAny UnrecognizedTagToAnyMode
+
+	// TimeTagToAnyMode specifies how to decode CBOR tag 0 and 1 into an empty interface (any).
+	// Based on the specified mode, Unmarshal can return a time.Time value or a time string in a specific format.
+	TimeTagToAny TimeTagToAnyMode
 }
 
 // DecMode returns DecMode with immutable options and no tags (safe for concurrency).
@@ -717,6 +745,10 @@ func (opts DecOptions) decMode() (*decMode, error) {
 		return nil, errors.New("cbor: invalid UnrecognizedTagToAnyMode " + strconv.Itoa(int(opts.UnrecognizedTagToAny)))
 	}
 
+	if !opts.TimeTagToAny.valid() {
+		return nil, errors.New("cbor: invalid TimeTagToAny " + strconv.Itoa(int(opts.TimeTagToAny)))
+	}
+
 	dm := decMode{
 		dupMapKey:             opts.DupMapKey,
 		timeTag:               opts.TimeTag,
@@ -736,6 +768,7 @@ func (opts DecOptions) decMode() (*decMode, error) {
 		byteStringToString:    opts.ByteStringToString,
 		fieldNameByteString:   opts.FieldNameByteString,
 		unrecognizedTagToAny:  opts.UnrecognizedTagToAny,
+		timeTagToAny:          opts.TimeTagToAny,
 	}
 
 	return &dm, nil
@@ -807,6 +840,7 @@ type decMode struct {
 	byteStringToString    ByteStringToStringMode
 	fieldNameByteString   FieldNameByteStringMode
 	unrecognizedTagToAny  UnrecognizedTagToAnyMode
+	timeTagToAny          TimeTagToAnyMode
 }
 
 var defaultDecMode, _ = DecOptions{}.decMode()
@@ -832,6 +866,7 @@ func (dm *decMode) DecOptions() DecOptions {
 		ByteStringToString:    dm.byteStringToString,
 		FieldNameByteString:   dm.fieldNameByteString,
 		UnrecognizedTagToAny:  dm.unrecognizedTagToAny,
+		TimeTagToAny:          dm.timeTagToAny,
 	}
 }
 
@@ -1503,7 +1538,25 @@ func (d *decoder) parse(skipSelfDescribedTag bool) (interface{}, error) { //noli
 		case 0, 1:
 			d.off = tagOff
 			tm, _, err := d.parseToTime()
-			return tm, err
+			if err != nil {
+				return nil, err
+			}
+			switch d.dm.timeTagToAny {
+			case TimeTagToTime:
+				return tm, nil
+			case TimeTagToRFC3339:
+				if tagNum == 1 {
+					tm = tm.UTC()
+				}
+				return tm.Format(time.RFC3339), nil
+			case TimeTagToRFC3339Nano:
+				if tagNum == 1 {
+					tm = tm.UTC()
+				}
+				return tm.Format(time.RFC3339Nano), nil
+			default:
+				// not reachable
+			}
 		case 2:
 			b, _ := d.parseByteString()
 			bi := new(big.Int).SetBytes(b)

diff --git a/decode_test.go b/decode_test.go
@@ -4912,6 +4912,7 @@ func TestDecOptions(t *testing.T) {
 		ByteStringToString:    ByteStringToStringAllowed,
 		FieldNameByteString:   FieldNameByteStringAllowed,
 		UnrecognizedTagToAny:  UnrecognizedTagContentToAny,
+		TimeTagToAny:          TimeTagToRFC3339,
 	}
 	ov := reflect.ValueOf(opts1)
 	for i := 0; i < ov.NumField(); i++ {
@@ -8658,3 +8659,92 @@ func TestUnmarshalWithUnrecognizedTagToAnyModeForSharedTag(t *testing.T) {
 func isCBORNil(data []byte) bool {
 	return len(data) > 0 && (data[0] == 0xf6 || data[0] == 0xf7)
 }
+
+func TestDecModeInvalidTimeTagToAnyMode(t *testing.T) {
+	for _, tc := range []struct {
+		name         string
+		opts         DecOptions
+		wantErrorMsg string
+	}{
+		{
+			name:         "below range of valid modes",
+			opts:         DecOptions{TimeTagToAny: -1},
+			wantErrorMsg: "cbor: invalid TimeTagToAny -1",
+		},
+		{
+			name:         "above range of valid modes",
+			opts:         DecOptions{TimeTagToAny: 4},
+			wantErrorMsg: "cbor: invalid TimeTagToAny 4",
+		},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			_, err := tc.opts.DecMode()
+			if err == nil {
+				t.Errorf("Expected non nil error from DecMode()")
+			} else if err.Error() != tc.wantErrorMsg {
+				t.Errorf("Expected error: %q, want: %q \n", tc.wantErrorMsg, err.Error())
+			}
+		})
+	}
+}
+
+func TestDecModeTimeTagToAny(t *testing.T) {
+	for _, tc := range []struct {
+		name string
+		opts DecOptions
+		in   []byte
+		want interface{}
+	}{
+		{
+			name: "Unmarshal tag 0 data to time.Time when TimeTagToAny is not set",
+			opts: DecOptions{},
+			in:   hexDecode("c074323031332d30332d32315432303a30343a30305a"),
+			want: time.Date(2013, 3, 21, 20, 4, 0, 0, time.UTC),
+		},
+		{
+			name: "Unmarshal tag 1 data to time.Time when TimeTagToAny is not set",
+			opts: DecOptions{},
+			in:   hexDecode("c11a514b67b0"),
+			want: time.Date(2013, 3, 21, 20, 4, 0, 0, time.UTC),
+		},
+		{
+			name: "Unmarshal tag 0 data to RFC3339 string when TimeTagToAny is set",
+			opts: DecOptions{TimeTagToAny: TimeTagToRFC3339},
+			in:   hexDecode("c074323031332d30332d32315432303a30343a30305a"),
+			want: "2013-03-21T20:04:00Z",
+		},
+		{
+			name: "Unmarshal tag 1 data to RFC3339 string when TimeTagToAny is set",
+			opts: DecOptions{TimeTagToAny: TimeTagToRFC3339},
+			in:   hexDecode("c11a514b67b0"),
+			want: "2013-03-21T20:04:00Z",
+		},
+		{
+			name: "Unmarshal tag 0 data to RFC3339Nano string when TimeTagToAny is set",
+			opts: DecOptions{TimeTagToAny: TimeTagToRFC3339Nano},
+			in:   hexDecode("c076323031332d30332d32315432303a30343a30302e355a"),
+			want: "2013-03-21T20:04:00.5Z",
+		},
+		{
+			name: "Unmarshal tag 1 data to RFC3339Nano string when TimeTagToAny is set",
+			opts: DecOptions{TimeTagToAny: TimeTagToRFC3339Nano},
+			in:   hexDecode("c1fb41d452d9ec200000"),
+			want: "2013-03-21T20:04:00.5Z",
+		},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			dm, err := tc.opts.DecMode()
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			var got interface{}
+			if err := dm.Unmarshal(tc.in, &got); err != nil {
+				t.Errorf("unexpected error: %v", err)
+			}
+
+			compareNonFloats(t, tc.in, got, tc.want)
+
+		})
+	}
+}