func (d Destination) MarshalXML(e *xml.Encoder, start xml.StartElement) error {
	if err := e.EncodeToken(start); err != nil {
		return err
	}
	if err := e.EncodeElement(d.String(), xml.StartElement{Name: xml.Name{Local: "Bucket"}}); err != nil {
		return err
	}
	if d.StorageClass != "" {
		if err := e.EncodeElement(d.StorageClass, xml.StartElement{Name: xml.Name{Local: "StorageClass"}}); err != nil {
			return err
		}
	}

}

// MarshalXML encodes expiration date if it is non-zero and encodes
// empty string otherwise
func (t DeleteMarkerMTime) MarshalXML(e *xml.Encoder, startElement xml.StartElement) error {
	if t.Time.IsZero() {
		return nil
	}
	return e.EncodeElement(t.Time.Format(time.RFC3339), startElement)
}

// ObjectV object version key/versionId
type ObjectV struct {
	ObjectName string `xml:"Key"`
	VersionID  string `xml:"VersionId"`
}

func (de DelMarkerExpiration) Empty() bool {
	return de.Days == 0
}

// UnmarshalXML decodes a single XML element into a DelMarkerExpiration value
func (de *DelMarkerExpiration) UnmarshalXML(dec *xml.Decoder, start xml.StartElement) error {
	type delMarkerExpiration DelMarkerExpiration
	var dexp delMarkerExpiration
	err := dec.DecodeElement(&dexp, &start)
	if err != nil {
		return err
	}

	if dexp.Days <= 0 {