// Scan XML token stream for next element and save into val.
// If val == nil, allocate new element based on proto map.
// Either way, return val.
func next(c interfaces.Conn) (xml.Name, interface{}, error) {
elem, err := nextElement(c.In())
if err != nil {
return xml.Name{}, nil, err
}
c.Lock().Lock()
defer c.Lock().Unlock()
switch el := elem.(type) {
case xml.StartElement:
return decodeStartElement(c, el)
case xml.EndElement:
return decodeEndElement(el)
}
return xml.Name{}, nil, fmt.Errorf("unexpected element %s", elem)
}
