public static @Nullable String getHrefBase(XmlFile file) {
    final XmlTag root = file.getRootTag();
    final XmlTag head = root != null ? root.findFirstSubTag("head") : null;
    final XmlTag base = head != null ? head.findFirstSubTag("base") : null;
    return base != null ? base.getAttributeValue("href") : null;
  }
public static @Nullable String getHrefBase(XmlFile file)