@Override
  @Nullable
  public Document getDocument(@NotNull final VirtualFile file) {
    DocumentEx document = (DocumentEx) getCachedDocument(file);
    if (document == null) {
      if (file.isDirectory()
          || isBinaryWithoutDecompiler(file)
          || SingleRootFileViewProvider.isTooLargeForContentLoading(file)) {
        return null;
      }
      final CharSequence text = LoadTextUtil.loadText(file);

      synchronized (lock) {
        document = (DocumentEx) getCachedDocument(file);
        if (document != null) return document; // Double checking

        document = (DocumentEx) createDocument(text);
        document.setModificationStamp(file.getModificationStamp());
        final FileType fileType = file.getFileType();
        document.setReadOnly(!file.isWritable() || fileType.isBinary());
        file.putUserData(DOCUMENT_KEY, new WeakReference<Document>(document));
        document.putUserData(FILE_KEY, file);

        if (!(file instanceof LightVirtualFile
            || file.getFileSystem() instanceof DummyFileSystem)) {
          document.addDocumentListener(
              new DocumentAdapter() {
                @Override
                public void documentChanged(DocumentEvent e) {
                  final Document document = e.getDocument();
                  myUnsavedDocuments.add(document);
                  final Runnable currentCommand =
                      CommandProcessor.getInstance().getCurrentCommand();
                  Project project =
                      currentCommand == null
                          ? null
                          : CommandProcessor.getInstance().getCurrentCommandProject();
                  String lineSeparator = CodeStyleFacade.getInstance(project).getLineSeparator();
                  document.putUserData(LINE_SEPARATOR_KEY, lineSeparator);

                  // avoid documents piling up during batch processing
                  if (areTooManyDocumentsInTheQueue(myUnsavedDocuments)) {
                    saveAllDocumentsLater();
                  }
                }
              });
        }
      }

      myMultiCaster.fileContentLoaded(file, document);
    }

    return document;
  }
 public static void registerDocument(
     @NotNull final Document document, @NotNull VirtualFile virtualFile) {
   synchronized (lock) {
     virtualFile.putUserData(
         DOCUMENT_KEY,
         new SoftReference<Document>(document) {
           @Override
           public Document get() {
             return document;
           }
         });
     document.putUserData(FILE_KEY, virtualFile);
   }
 }
  @Override
  @Nullable
  public Document getCachedDocument(@NotNull VirtualFile file) {
    Reference<Document> reference = file.getUserData(DOCUMENT_KEY);
    Document document = reference == null ? null : reference.get();

    if (document != null && isBinaryWithoutDecompiler(file)) {
      file.putUserData(DOCUMENT_KEY, null);
      document.putUserData(FILE_KEY, null);
      return null;
    }

    return document;
  }