ua: decode types that convert to time.Time

The codec does not handle types that can be converted to time.Time
correctly since it is too strict in determining what a time.Time type
is. This patch relaxes this by checking if a type can be converted to
time.Time.

Fixes #633

ua/decode.go

@@ -23,7 +23,7 @@ func isBinaryDecoder(val reflect.Value) bool {
 }
 
 func isTime(val reflect.Value) bool {
-	return val.Type() == timeType
+	return val.CanConvert(timeType)
 }
 
 type BinaryDecoder interface {
@@ -49,7 +49,7 @@ func decode(b []byte, val reflect.Value, name string) (n int, err error) {
 		v := val.Interface().(BinaryDecoder)
 		return v.Decode(b)
 	case isTime(val):
-		val.Set(reflect.ValueOf(buf.ReadTime()))
+		val.Set(reflect.ValueOf(buf.ReadTime()).Convert(val.Type()))
 	default:
 		// fmt.Printf("decode: %s is a %s\n", name, val.Kind())
 		switch val.Kind() {

ua/decode_test.go

@@ -25,7 +25,10 @@ type C struct {
 	B [2]byte
 }
 
+type Timestamp time.Time
+
 func TestCodec(t *testing.T) {
+
 	tests := []struct {
 		name string
 		v    interface{}
@@ -205,6 +208,16 @@ func TestCodec(t *testing.T) {
 			v:    &struct{ V time.Time }{time.Time{}},
 			b:    []byte{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
 		},
+		{
+			name: "DateTime as Timestamp",
+			v:    &struct{ V Timestamp }{Timestamp(time.Date(2018, time.August, 10, 23, 0, 0, 0, time.UTC))},
+			b:    []byte{0x00, 0x98, 0x67, 0xdd, 0xfd, 0x30, 0xd4, 0x01},
+		},
+		{
+			name: "DateTimeZero as Timestamp",
+			v:    &struct{ V Timestamp }{Timestamp{}},
+			b:    []byte{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
+		},
 		{
 			name: "[]uint32==nil",
 			v:    &struct{ V []uint32 }{},

ua/encode.go

@@ -46,7 +46,7 @@ func encode(val reflect.Value, name string) ([]byte, error) {
 		return v.Encode()
 
 	case isTime(val):
-		buf.WriteTime(val.Interface().(time.Time))
+		buf.WriteTime(val.Convert(timeType).Interface().(time.Time))
 
 	default:
 		switch val.Kind() {