public static void handleError(
      SAXParseException ex, PsiFile file, Document document, ValidationMessageConsumer consumer) {
    final String systemId = ex.getSystemId();
    if (LOG.isDebugEnabled()) {
      LOG.debug("RNG Schema error: " + ex.getMessage() + " [" + systemId + "]");
    }

    if (systemId != null) {
      final VirtualFile virtualFile = findVirtualFile(systemId);
      if (!Comparing.equal(virtualFile, file.getVirtualFile())) {
        return;
      }
    }

    final PsiElement at;
    final int line = ex.getLineNumber();
    if (line > 0) {
      final int column = ex.getColumnNumber();
      final int startOffset = document.getLineStartOffset(line - 1);

      if (column > 0) {
        if (file.getFileType() == RncFileType.getInstance()) {
          final PsiElement e = file.findElementAt(startOffset + column);
          if (e == null) {
            at = e;
          } else {
            at = file.findElementAt(startOffset + column - 1);
          }
        } else {
          at = file.findElementAt(startOffset + column - 2);
        }
      } else {
        final PsiElement e = file.findElementAt(startOffset);
        at = e != null ? PsiTreeUtil.nextLeaf(e) : null;
      }
    } else {
      final XmlDocument d = ((XmlFile) file).getDocument();
      assert d != null;
      final XmlTag rootTag = d.getRootTag();
      assert rootTag != null;
      at = rootTag.getFirstChild();
    }

    final PsiElement host;
    if (file instanceof RncFile) {
      host = at;
    } else {
      host = PsiTreeUtil.getParentOfType(at, XmlAttribute.class, XmlTag.class);
    }
    if (at != null && host != null) {
      consumer.onMessage(host, ex.getMessage());
    } else {
      consumer.onMessage(file, ex.getMessage());
    }
  }
  @Nullable
  @Override
  public MyValidationMessageConsumer collectInformation(@NotNull final PsiFile file) {
    final FileType type = file.getFileType();
    if (type != StdFileTypes.XML && type != RncFileType.getInstance()) {
      return null;
    }
    final XmlFile xmlfile = (XmlFile) file;
    final XmlDocument document = xmlfile.getDocument();
    if (document == null) {
      return null;
    }
    if (type == StdFileTypes.XML) {
      final XmlTag rootTag = document.getRootTag();
      if (rootTag == null) {
        return null;
      }
      if (!ApplicationLoader.RNG_NAMESPACE.equals(rootTag.getNamespace())) {
        return null;
      }
    } else {
      if (!ApplicationManager.getApplication().isUnitTestMode()
          && MyErrorFinder.hasError(xmlfile)) {
        return null;
      }
    }
    final Document doc = PsiDocumentManager.getInstance(file.getProject()).getDocument(file);

    final MyValidationMessageConsumer consumer = new MyValidationMessageConsumer();
    ErrorHandler eh =
        new DefaultHandler() {
          @Override
          public void warning(SAXParseException e) {
            handleError(e, file, doc, consumer.warning());
          }

          @Override
          public void error(SAXParseException e) {
            handleError(e, file, doc, consumer.error());
          }
        };

    RngParser.parsePattern(file, eh, true);
    return consumer;
  }
  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;
  }