private void checkTagByDescriptor(final XmlTag tag) {
    String name = tag.getName();

    XmlElementDescriptor elementDescriptor;

    final PsiElement parent = tag.getParent();
    if (parent instanceof XmlTag) {
      XmlTag parentTag = (XmlTag) parent;

      elementDescriptor = XmlUtil.getDescriptorFromContext(tag);

      final XmlElementDescriptor parentDescriptor = parentTag.getDescriptor();

      if (parentDescriptor != null && elementDescriptor == null && shouldBeValidated(tag)) {
        if (tag instanceof HtmlTag) {
          // XmlEntitiesInspection inspection = getInspectionProfile(tag,
          // HtmlStyleLocalInspection.SHORT_NAME);
          // if (inspection != null /*&&
          // isAdditionallyDeclared(inspection.getAdditionalEntries(XmlEntitiesInspection.UNKNOWN_TAG), name)*/) {
          return;
          // }
        }

        addElementsForTag(
            tag,
            XmlErrorMessages.message("element.is.not.allowed.here", name),
            getTagProblemInfoType(tag),
            null);
        return;
      }

      if (elementDescriptor instanceof AnyXmlElementDescriptor || elementDescriptor == null) {
        elementDescriptor = tag.getDescriptor();
      }

      if (elementDescriptor == null) return;
    } else {
      // root tag
      elementDescriptor = tag.getDescriptor();

      if (elementDescriptor == null) {
        addElementsForTag(
            tag,
            XmlErrorMessages.message("element.must.be.declared", name),
            HighlightInfoType.WRONG_REF,
            null);
        return;
      }
    }

    checkRequiredAttributes(tag, name, elementDescriptor);

    if (elementDescriptor instanceof Validator) {
      //noinspection unchecked
      ((Validator<XmlTag>) elementDescriptor).validate(tag, this);
    }
  }
  @Override
  public void visitXmlAttributeValue(XmlAttributeValue value) {
    final PsiElement parent = value.getParent();
    if (!(parent instanceof XmlAttribute)) {
      checkReferences(value);
      return;
    }

    XmlAttribute attribute = (XmlAttribute) parent;

    XmlTag tag = attribute.getParent();

    XmlElementDescriptor elementDescriptor = tag.getDescriptor();
    XmlAttributeDescriptor attributeDescriptor =
        elementDescriptor != null ? elementDescriptor.getAttributeDescriptor(attribute) : null;

    if (attributeDescriptor != null && !skipValidation(value)) {
      String error = attributeDescriptor.validateValue(value, attribute.getValue());

      if (error != null) {
        addToResults(HighlightInfo.createHighlightInfo(getTagProblemInfoType(tag), value, error));
        return;
      }
    }

    checkReferences(value);
  }
 @Override
 public void visitXmlTag(XmlTag tag) {
   super.visitXmlTag(tag);
   final XmlElementDescriptor descriptor = tag.getDescriptor();
   if (descriptor instanceof JavaFxClassTagDescriptorBase) {
     appendClassName(descriptor.getDeclaration());
   } else if (descriptor instanceof JavaFxPropertyTagDescriptor
       && ((JavaFxPropertyTagDescriptor) descriptor).isStatic()) {
     final PsiElement declaration = descriptor.getDeclaration();
     if (declaration instanceof PsiMember) {
       appendClassName(((PsiMember) declaration).getContainingClass());
     }
   }
 }
  @Nullable
  protected XmlElementDescriptor computeElementDescriptor() {
    for (XmlElementDescriptorProvider provider :
        Extensions.getExtensions(XmlElementDescriptorProvider.EP_NAME)) {
      XmlElementDescriptor elementDescriptor = provider.getDescriptor(this);
      if (elementDescriptor != null) {
        return elementDescriptor;
      }
    }

    final String namespace = getNamespace();
    if (XmlUtil.EMPTY_URI.equals(namespace)) { // nonqualified items
      final XmlTag parent = getParentTag();
      if (parent != null) {
        final XmlElementDescriptor descriptor = parent.getDescriptor();
        if (descriptor != null) {
          XmlElementDescriptor fromParent = descriptor.getElementDescriptor(this, parent);
          if (fromParent != null && !(fromParent instanceof AnyXmlElementDescriptor)) {
            return fromParent;
          }
        }
      }
    }

    XmlElementDescriptor elementDescriptor = null;
    final XmlNSDescriptor nsDescriptor = getNSDescriptor(namespace, false);

    LOG.debug(
        "Descriptor for namespace "
            + namespace
            + " is "
            + (nsDescriptor != null ? nsDescriptor.getClass().getCanonicalName() : "NULL"));

    if (nsDescriptor != null) {
      if (!DumbService.getInstance(getProject()).isDumb()
          || DumbService.isDumbAware(nsDescriptor)) {
        elementDescriptor = nsDescriptor.getElementDescriptor(this);
      }
    }
    if (elementDescriptor == null) {
      return XmlUtil.findXmlDescriptorByType(this);
    }

    return elementDescriptor;
  }
  private void checkTag(XmlTag tag) {
    if (ourDoJaxpTesting) return;

    if (!myHolder.hasErrorResults()) {
      checkTagByDescriptor(tag);
    }

    if (!myHolder.hasErrorResults()) {
      if (!skipValidation(tag)) {
        final XmlElementDescriptor descriptor = tag.getDescriptor();

        if (tag instanceof HtmlTag
            && (descriptor instanceof AnyXmlElementDescriptor || descriptor == null)) {
          return;
        }

        checkReferences(tag);
      }
    }
  }
  public Result beforeCharTyped(
      final char c,
      final Project project,
      final Editor editor,
      final PsiFile editedFile,
      final FileType fileType) {
    final XmlEditorOptions xmlEditorOptions = XmlEditorOptions.getInstance();
    if (c == '>'
        && xmlEditorOptions != null
        && xmlEditorOptions.isAutomaticallyInsertClosingTag()
        && (editedFile.getLanguage() instanceof XMLLanguage
            || editedFile.getViewProvider().getBaseLanguage() instanceof XMLLanguage)) {
      PsiDocumentManager.getInstance(project).commitAllDocuments();

      PsiFile file = PsiDocumentManager.getInstance(project).getPsiFile(editor.getDocument());
      FileViewProvider provider = editedFile.getViewProvider();
      int offset = editor.getCaretModel().getOffset();

      PsiElement element, elementAtCaret = null;

      if (offset < editor.getDocument().getTextLength()) {
        elementAtCaret = element = provider.findElementAt(offset, XMLLanguage.class);

        if (!(element instanceof PsiWhiteSpace)) {
          boolean nonAcceptableDelimiter = true;

          if (element instanceof XmlToken) {
            IElementType tokenType = ((XmlToken) element).getTokenType();

            if (tokenType == XmlTokenType.XML_START_TAG_START
                || tokenType == XmlTokenType.XML_END_TAG_START) {
              if (offset > 0) {
                PsiElement previousElement = provider.findElementAt(offset - 1, XMLLanguage.class);

                if (previousElement instanceof XmlToken) {
                  tokenType = ((XmlToken) previousElement).getTokenType();
                  element = previousElement;
                  nonAcceptableDelimiter = false;
                }
              }
            } else if (tokenType == XmlTokenType.XML_NAME) {
              if (element.getNextSibling() instanceof PsiErrorElement) {
                nonAcceptableDelimiter = false;
              }
            }

            if (tokenType == XmlTokenType.XML_TAG_END
                || tokenType == XmlTokenType.XML_EMPTY_ELEMENT_END
                    && element.getTextOffset() == offset - 1) {
              editor.getCaretModel().moveToOffset(offset + 1);
              editor.getScrollingModel().scrollToCaret(ScrollType.RELATIVE);
              return Result.STOP;
            }
          }
          if (nonAcceptableDelimiter) return Result.CONTINUE;
        } else {
          // check if right after empty end
          PsiElement previousElement = provider.findElementAt(offset - 1, XMLLanguage.class);
          if (previousElement instanceof XmlToken) {
            final IElementType tokenType = ((XmlToken) previousElement).getTokenType();

            if (tokenType == XmlTokenType.XML_EMPTY_ELEMENT_END) {
              return Result.STOP;
            }
          }
        }

        PsiElement parent = element.getParent();
        if (parent instanceof XmlText) {
          final String text = parent.getText();
          // check /
          final int index = offset - parent.getTextOffset() - 1;

          if (index >= 0 && text.charAt(index) == '/') {
            return Result.CONTINUE; // already seen /
          }
          element = parent.getPrevSibling();
        } else if (parent instanceof XmlTag && !(element.getPrevSibling() instanceof XmlTag)) {
          element = parent;
        } else if (parent instanceof XmlAttributeValue) {
          element = parent;
        }
      } else {
        element =
            provider.findElementAt(editor.getDocument().getTextLength() - 1, XMLLanguage.class);
        if (element == null) return Result.CONTINUE;
        element = element.getParent();
      }

      if (offset > 0 && offset <= editor.getDocument().getTextLength()) {
        if (editor.getDocument().getCharsSequence().charAt(offset - 1)
            == '/') { // Some languages (e.g. GSP) allow character '/' in tag name.
          return Result.CONTINUE;
        }
      }

      if (element instanceof XmlAttributeValue) {
        element = element.getParent().getParent();
      }

      while (element instanceof PsiWhiteSpace) element = element.getPrevSibling();
      if (element instanceof XmlDocument) { // hack for closing tags in RHTML
        element = element.getLastChild();
      }
      if (element == null) return Result.CONTINUE;
      if (!(element instanceof XmlTag)) {
        if (element instanceof XmlTokenImpl
            && element.getPrevSibling() != null
            && element.getPrevSibling().getText().equals("<")) {
          // tag is started and there is another text in the end
          editor.getDocument().insertString(offset, "</" + element.getText() + ">");
        }
        return Result.CONTINUE;
      }

      XmlTag tag = (XmlTag) element;
      if (XmlUtil.getTokenOfType(tag, XmlTokenType.XML_TAG_END) != null) return Result.CONTINUE;
      if (XmlUtil.getTokenOfType(tag, XmlTokenType.XML_EMPTY_ELEMENT_END) != null)
        return Result.CONTINUE;
      final XmlToken startToken = XmlUtil.getTokenOfType(tag, XmlTokenType.XML_START_TAG_START);
      if (startToken == null || !startToken.getText().equals("<")) return Result.CONTINUE;

      String name = tag.getName();
      if (elementAtCaret instanceof XmlToken
          && ((XmlToken) elementAtCaret).getTokenType() == XmlTokenType.XML_NAME) {
        name = name.substring(0, offset - elementAtCaret.getTextOffset());
      }
      if (tag instanceof HtmlTag && HtmlUtil.isSingleHtmlTag(name)) return Result.CONTINUE;
      if ("".equals(name)) return Result.CONTINUE;

      int tagOffset = tag.getTextRange().getStartOffset();

      final XmlToken nameToken = XmlUtil.getTokenOfType(tag, XmlTokenType.XML_NAME);
      if (nameToken != null && nameToken.getTextRange().getStartOffset() > offset)
        return Result.CONTINUE;

      HighlighterIterator iterator = ((EditorEx) editor).getHighlighter().createIterator(tagOffset);
      if (BraceMatchingUtil.matchBrace(
          editor.getDocument().getCharsSequence(),
          editedFile.getFileType(),
          iterator,
          true,
          true)) {
        PsiElement parent = tag.getParent();
        boolean hasBalance = true;

        while (parent instanceof XmlTag && name.equals(((XmlTag) parent).getName())) {
          ASTNode astNode = XmlChildRole.CLOSING_TAG_NAME_FINDER.findChild(parent.getNode());
          if (astNode == null) {
            hasBalance = false;
            break;
          }

          parent = parent.getParent();
        }

        if (hasBalance) {
          hasBalance = false;
          for (ASTNode node = parent.getNode().getLastChildNode();
              node != null;
              node = node.getTreePrev()) {
            ASTNode leaf = node;
            if (leaf.getElementType() == TokenType.ERROR_ELEMENT) {
              ASTNode firstChild = leaf.getFirstChildNode();
              if (firstChild != null) leaf = firstChild;
              else {
                PsiElement psiElement = PsiTreeUtil.nextLeaf(leaf.getPsi());
                leaf = psiElement != null ? psiElement.getNode() : null;
              }
              if (leaf != null && leaf.getElementType() == TokenType.WHITE_SPACE) {
                PsiElement psiElement = PsiTreeUtil.nextLeaf(leaf.getPsi());
                if (psiElement != null) leaf = psiElement.getNode();
              }
            }

            if (leaf != null && leaf.getElementType() == XmlTokenType.XML_END_TAG_START) {
              ASTNode treeNext = leaf.getTreeNext();
              IElementType treeNextType;
              if (treeNext != null
                  && ((treeNextType = treeNext.getElementType()) == XmlTokenType.XML_NAME
                      || treeNextType == XmlTokenType.XML_TAG_NAME)) {
                if (name.equals(treeNext.getText())) {
                  ASTNode parentEndName =
                      parent instanceof XmlTag
                          ? XmlChildRole.CLOSING_TAG_NAME_FINDER.findChild(parent.getNode())
                          : null;
                  hasBalance =
                      !(parent instanceof XmlTag)
                          || parentEndName != null && !parentEndName.getText().equals(name);
                  break;
                }
              }
            }
          }
        }

        if (hasBalance) return Result.CONTINUE;
      }

      TextRange cdataReformatRange = null;
      final XmlElementDescriptor descriptor = tag.getDescriptor();

      if (descriptor instanceof XmlElementDescriptorWithCDataContent) {
        final XmlElementDescriptorWithCDataContent cDataContainer =
            (XmlElementDescriptorWithCDataContent) descriptor;

        if (cDataContainer.requiresCdataBracesInContext(tag)) {
          int rangeStart = offset;
          @NonNls final String cDataStart = "><![CDATA[";
          final String inserted = cDataStart + "\n]]>";
          editor.getDocument().insertString(offset, inserted);
          final int newoffset = offset + cDataStart.length();
          editor.getCaretModel().moveToOffset(newoffset);
          offset += inserted.length();
          cdataReformatRange = new TextRange(rangeStart, offset + 1);
        }
      }

      editor.getDocument().insertString(offset, "</" + name + ">");

      if (cdataReformatRange != null) {
        PsiDocumentManager.getInstance(project).commitDocument(editor.getDocument());
        try {
          CodeStyleManager.getInstance(project)
              .reformatText(
                  file, cdataReformatRange.getStartOffset(), cdataReformatRange.getEndOffset());
        } catch (IncorrectOperationException e) {
          LOG.error(e);
        }
      }
      return cdataReformatRange != null ? Result.STOP : Result.CONTINUE;
    }
    return Result.CONTINUE;
  }
  private void checkAttribute(XmlAttribute attribute) {
    XmlTag tag = attribute.getParent();

    final String name = attribute.getName();
    PsiElement prevLeaf = PsiTreeUtil.prevLeaf(attribute);

    if (!(prevLeaf instanceof PsiWhiteSpace)) {
      TextRange textRange = attribute.getTextRange();
      addToResults(
          HighlightInfo.createHighlightInfo(
              tag instanceof HtmlTag ? HighlightInfoType.WARNING : HighlightInfoType.ERROR,
              textRange.getStartOffset(),
              textRange.getStartOffset(),
              XmlErrorMessages.message("attribute.should.be.preceded.with.space")));
    }

    if (attribute.isNamespaceDeclaration()) {
      checkReferences(attribute.getValueElement());
      return;
    }
    final String namespace = attribute.getNamespace();

    if (XmlUtil.XML_SCHEMA_INSTANCE_URI.equals(namespace)) {
      checkReferences(attribute.getValueElement());
      return;
    }

    XmlElementDescriptor elementDescriptor = tag.getDescriptor();
    if (elementDescriptor == null
        || elementDescriptor instanceof AnyXmlElementDescriptor
        || ourDoJaxpTesting) {
      return;
    }

    XmlAttributeDescriptor attributeDescriptor =
        elementDescriptor.getAttributeDescriptor(attribute);

    if (attributeDescriptor == null) {
      if (!XmlUtil.attributeFromTemplateFramework(name, tag)) {
        final String localizedMessage =
            XmlErrorMessages.message("attribute.is.not.allowed.here", name);
        final HighlightInfo highlightInfo =
            reportAttributeProblem(tag, name, attribute, localizedMessage);
        if (highlightInfo != null) {
          final XmlFile xmlFile = (XmlFile) tag.getContainingFile();
          if (xmlFile != null) {
            XmlExtension.getExtension(xmlFile).createAddAttributeFix(attribute, highlightInfo);
          }
        }
      }
    } else {
      checkDuplicateAttribute(tag, attribute);

      if (tag instanceof HtmlTag
          && attribute.getValueElement() == null
          && !HtmlUtil.isSingleHtmlAttribute(name)) {
        final String localizedMessage =
            XmlErrorMessages.message("empty.attribute.is.not.allowed", name);
        reportAttributeProblem(tag, name, attribute, localizedMessage);
      }

      // we skip resolve of attribute references since there is separate check when taking attribute
      // descriptors
      PsiReference[] attrRefs = attribute.getReferences();
      doCheckRefs(attribute, attrRefs, attribute.getNamespacePrefix().length() > 0 ? 2 : 1);
    }
  }