private boolean isGeneratedFromDtd(XmlNSDescriptor defaultNSDescriptorInner) {
   if (defaultNSDescriptorInner == null) {
     return false;
   }
   XmlFile descriptorFile = defaultNSDescriptorInner.getDescriptorFile();
   if (descriptorFile == null) {
     return false;
   }
   @NonNls String otherName = XmlUtil.getContainingFile(this).getName() + ".dtd";
   return descriptorFile.getName().equals(otherName);
 }
  private XmlNSDescriptor getDefaultNSDescriptorInner(
      final String namespace, final boolean strict) {
    final XmlFile containingFile = XmlUtil.getContainingFile(this);
    if (containingFile == null) return null;
    final XmlProlog prolog = getProlog();
    final XmlDoctype doctype = prolog != null ? prolog.getDoctype() : null;
    boolean dtdUriFromDocTypeIsNamespace = false;

    if (XmlUtil.HTML_URI.equals(namespace)) {
      XmlNSDescriptor nsDescriptor =
          doctype != null ? getNsDescriptorFormDocType(doctype, containingFile, true) : null;
      if (doctype != null) {
        LOG.debug(
            "Descriptor from doctype "
                + doctype
                + " is "
                + (nsDescriptor != null ? nsDescriptor.getClass().getCanonicalName() : "NULL"));
      }

      if (nsDescriptor == null) {
        String htmlns =
            ExternalResourceManagerEx.getInstanceEx().getDefaultHtmlDoctype(getProject());
        if (htmlns.isEmpty()) {
          htmlns = Html5SchemaProvider.getHtml5SchemaLocation();
        }
        nsDescriptor = getDefaultNSDescriptor(htmlns, false);
      }
      return new HtmlNSDescriptorImpl(nsDescriptor);
    } else if (XmlUtil.XHTML_URI.equals(namespace)) {
      String xhtmlNamespace = XmlUtil.getDefaultXhtmlNamespace(getProject());
      if (xhtmlNamespace == null || xhtmlNamespace.isEmpty()) {
        xhtmlNamespace = Html5SchemaProvider.getXhtml5SchemaLocation();
      }
      return getDefaultNSDescriptor(xhtmlNamespace, false);
    } else if (namespace != null && namespace != XmlUtil.EMPTY_URI) {
      if (doctype == null || !namespace.equals(XmlUtil.getDtdUri(doctype))) {
        boolean documentIsSchemaThatDefinesNs =
            namespace.equals(XmlUtil.getTargetSchemaNsFromTag(getRootTag()));

        final XmlFile xmlFile =
            documentIsSchemaThatDefinesNs
                ? containingFile
                : XmlUtil.findNamespace(containingFile, namespace);
        if (xmlFile != null) {
          final XmlDocument document = xmlFile.getDocument();
          if (document != null) {
            return (XmlNSDescriptor) document.getMetaData();
          }
        }
      } else {
        dtdUriFromDocTypeIsNamespace = true;
      }
    }

    if (strict && !dtdUriFromDocTypeIsNamespace) return null;

    if (doctype != null) {
      XmlNSDescriptor descr = getNsDescriptorFormDocType(doctype, containingFile, false);

      if (descr != null) {
        return XmlExtension.getExtension(containingFile)
            .getDescriptorFromDoctype(containingFile, descr);
      }
    }

    if (strict) return null;
    if (namespace == XmlUtil.EMPTY_URI) {
      final XmlFile xmlFile = XmlUtil.findNamespace(containingFile, namespace);
      if (xmlFile != null) {
        return (XmlNSDescriptor) xmlFile.getDocument().getMetaData();
      }
    }
    try {
      final PsiFile fileFromText =
          PsiFileFactory.getInstance(getProject())
              .createFileFromText(
                  containingFile.getName() + ".dtd",
                  DTDLanguage.INSTANCE,
                  XmlUtil.generateDocumentDTD(this, false),
                  false,
                  false);
      if (fileFromText instanceof XmlFile) {
        fileFromText.putUserData(AUTO_GENERATED, Boolean.TRUE);
        return (XmlNSDescriptor) ((XmlFile) fileFromText).getDocument().getMetaData();
      }
    } catch (ProcessCanceledException ex) {
      throw ex;
    } catch (RuntimeException ignored) {
    } // e.g. dtd isn't mapped to xml type

    return null;
  }