public static boolean shouldBeValidated(@NotNull XmlTag tag) {
   PsiElement parent = tag.getParent();
   if (parent instanceof XmlTag) {
     return !skipValidation(parent) && !XmlUtil.tagFromTemplateFramework(tag);
   }
   return true;
 }
  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);
    }
  }
 @Nullable
 private static XmlElementDescriptor getDescriptorFromParent(
     final XmlTag tag, XmlElementDescriptor elementDescriptor) {
   final PsiElement parent = tag.getParent();
   if (parent instanceof XmlTag) {
     final XmlElementDescriptor descriptor = ((XmlTag) parent).getDescriptor();
     if (descriptor != null)
       elementDescriptor = descriptor.getElementDescriptor(tag, (XmlTag) parent);
   }
   return elementDescriptor;
 }
  public XmlElementDescriptor getElementDescriptor(@NotNull XmlTag tag) {
    PsiElement parent = tag.getParent();
    final String namespace = tag.getNamespace();
    while (parent instanceof XmlTag && !namespace.equals(((XmlTag) parent).getNamespace()))
      parent = parent.getContext();
    if (parent instanceof XmlTag) {
      final XmlTag parentTag = (XmlTag) parent;
      final XmlElementDescriptor parentDescriptor = parentTag.getDescriptor();

      if (parentDescriptor != null) {
        XmlElementDescriptor elementDescriptorFromParent =
            parentDescriptor.getElementDescriptor(tag, parentTag);

        if (elementDescriptorFromParent == null) {
          elementDescriptorFromParent = getDescriptorFromParent(tag, elementDescriptorFromParent);
        }
        if (elementDescriptorFromParent instanceof AnyXmlElementDescriptor) {
          final XmlElementDescriptor elementDescriptor =
              getElementDescriptor(tag.getLocalName(), namespace);
          if (elementDescriptor != null) return elementDescriptor;
        }
        return elementDescriptorFromParent;
      } else {
        return null;
      }
    } else {
      XmlElementDescriptor elementDescriptor =
          getElementDescriptor(tag.getLocalName(), tag.getNamespace());

      if (elementDescriptor == null) {
        elementDescriptor = getDescriptorFromParent(tag, elementDescriptor);
      }

      return elementDescriptor;
    }
  }
  @Override
  protected void checkTag(
      @NotNull final XmlTag tag, @NotNull final ProblemsHolder holder, final boolean isOnTheFly) {
    if (!(tag instanceof HtmlTag)
        || !XmlHighlightVisitor.shouldBeValidated(tag)
        || isInSpecialHtml5Namespace(tag)) {
      return;
    }

    XmlElementDescriptor descriptorFromContext = XmlUtil.getDescriptorFromContext(tag);

    PsiElement parent = tag.getParent();
    XmlElementDescriptor parentDescriptor =
        parent instanceof XmlTag ? ((XmlTag) parent).getDescriptor() : null;

    XmlElementDescriptor ownDescriptor =
        isAbstractDescriptor(descriptorFromContext) ? tag.getDescriptor() : descriptorFromContext;

    if (isAbstractDescriptor(ownDescriptor)
        || (parentDescriptor instanceof HtmlElementDescriptorImpl
            && ownDescriptor instanceof HtmlElementDescriptorImpl
            && isAbstractDescriptor(descriptorFromContext))) {

      final String name = tag.getName();

      if (!isCustomValuesEnabled() || !isCustomValue(name)) {
        final AddCustomTagOrAttributeIntentionAction action =
            new AddCustomTagOrAttributeIntentionAction(
                TAG_KEY, name, XmlEntitiesInspection.UNKNOWN_TAG);

        // todo: support "element is not allowed" message for html5
        // some tags in html5 cannot be found in xhtml5.xsd if they are located in incorrect
        // context, so they get any-element descriptor (ex. "canvas: tag)
        final String message =
            isAbstractDescriptor(ownDescriptor)
                ? XmlErrorMessages.message("unknown.html.tag", name)
                : XmlErrorMessages.message("element.is.not.allowed.here", name);

        final PsiElement startTagName = XmlTagUtil.getStartTagNameElement(tag);
        assert startTagName != null;
        final PsiElement endTagName = XmlTagUtil.getEndTagNameElement(tag);

        List<LocalQuickFix> quickfixes = new ArrayList<LocalQuickFix>();
        quickfixes.add(action);
        if (isOnTheFly) {
          ContainerUtil.addIfNotNull(
              CreateNSDeclarationIntentionFix.createFix(startTagName, ""), quickfixes);
        }
        if (HtmlUtil.isHtml5Tag(name) && !HtmlUtil.hasNonHtml5Doctype(tag)) {
          quickfixes.add(new SwitchToHtml5WithHighPriorityAction());
        }
        ProblemHighlightType highlightType =
            tag.getContainingFile().getContext() == null
                ? ProblemHighlightType.GENERIC_ERROR_OR_WARNING
                : ProblemHighlightType.INFORMATION;
        if (startTagName.getTextLength() > 0) {
          holder.registerProblem(
              startTagName,
              message,
              highlightType,
              quickfixes.toArray(new LocalQuickFix[quickfixes.size()]));
        }

        if (endTagName != null) {
          holder.registerProblem(
              endTagName,
              message,
              highlightType,
              quickfixes.toArray(new LocalQuickFix[quickfixes.size()]));
        }
      }
    }
  }
  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;
  }