@NotNull
  public XmlFile getContainingFile(@NotNull DomElement domElement) {
    if (domElement instanceof DomFileElement) {
      return ((DomFileElement) domElement).getFile();
    }
    DomInvocationHandler handler = DomManagerImpl.getDomInvocationHandler(domElement);
    assert handler != null : domElement;
    while (handler != null
        && !(handler instanceof DomRootInvocationHandler)
        && handler.getXmlTag() == null) {
      handler = handler.getParentHandler();
    }
    if (handler instanceof DomRootInvocationHandler) {
      return ((DomRootInvocationHandler) handler).getParent().getFile();
    }
    assert handler != null;
    XmlTag tag = handler.getXmlTag();
    assert tag != null;
    while (true) {
      final PsiElement parentTag = PhysicalDomParentStrategy.getParentTagCandidate(tag);
      if (!(parentTag instanceof XmlTag)) {
        return (XmlFile) tag.getContainingFile();
      }

      tag = (XmlTag) parentTag;
    }
  }
  @NotNull
  private static XmlFileHeader calcXmlFileHeader(final PsiFile file) {

    // if (file.getFileType() == XmlFileType.INSTANCE) {
    //  VirtualFile virtualFile = file.getVirtualFile();
    //  if (virtualFile instanceof VirtualFileWithId) {
    //    ObjectStubTree tree = StubTreeLoader.getInstance().readFromVFile(file.getProject(),
    // virtualFile);
    //    if (tree != null) {
    //      return ((FileStub)tree.getRoot()).getHeader();
    //    }
    //  }
    // }
    if (file instanceof XmlFile && file.getNode().isParsed()) {
      final XmlDocument document = ((XmlFile) file).getDocument();
      if (document != null) {
        String publicId = null;
        String systemId = null;
        final XmlProlog prolog = document.getProlog();
        if (prolog != null) {
          final XmlDoctype doctype = prolog.getDoctype();
          if (doctype != null) {
            publicId = doctype.getPublicId();
            systemId = doctype.getSystemId();
            if (systemId == null) {
              systemId = doctype.getDtdUri();
            }
          }
        }

        final XmlTag tag = document.getRootTag();
        if (tag != null) {
          String localName = tag.getLocalName();
          if (StringUtil.isNotEmpty(localName)) {
            if (tag.getPrevSibling() instanceof PsiErrorElement) {
              return XmlFileHeader.EMPTY;
            }

            String psiNs = tag.getNamespace();
            return new XmlFileHeader(
                localName,
                psiNs == XmlUtil.EMPTY_URI || Comparing.equal(psiNs, systemId) ? null : psiNs,
                publicId,
                systemId);
          }
        }
      }
      return XmlFileHeader.EMPTY;
    }

    if (!file.isValid()) return XmlFileHeader.EMPTY;
    return NanoXmlUtil.parseHeader(file);
  }
  private static XmlFileHeader computeHeaderByPsi(XmlFile file) {
    final XmlDocument document = file.getDocument();
    if (document == null) {
      return XmlFileHeader.EMPTY;
    }

    String publicId = null;
    String systemId = null;
    final XmlProlog prolog = document.getProlog();
    if (prolog != null) {
      final XmlDoctype doctype = prolog.getDoctype();
      if (doctype != null) {
        publicId = doctype.getPublicId();
        systemId = doctype.getSystemId();
        if (systemId == null) {
          systemId = doctype.getDtdUri();
        }
      }
    }

    final XmlTag tag = document.getRootTag();
    if (tag == null) {
      return XmlFileHeader.EMPTY;
    }

    String localName = tag.getLocalName();
    if (StringUtil.isNotEmpty(localName)) {
      if (tag.getPrevSibling() instanceof PsiErrorElement) {
        return XmlFileHeader.EMPTY;
      }

      String psiNs = tag.getNamespace();
      return new XmlFileHeader(
          localName,
          psiNs == XmlUtil.EMPTY_URI || Comparing.equal(psiNs, systemId) ? null : psiNs,
          publicId,
          systemId);
    }
    return XmlFileHeader.EMPTY;
  }