protected void addDirsToChildren(@NotNull List<? extends VirtualFile> roots,
                                   @NotNull ArrayList<? super AbstractTreeNode<?>> children,
                                   @NotNull TodoTreeBuilder builder) {
    final PsiManager psiManager = PsiManager.getInstance(myProject);
    for (VirtualFile dir : roots) {
      final PsiDirectory directory = psiManager.findDirectory(dir);
      if (directory == null) {
        continue;
      }
      final Iterator<PsiFile> files = builder.getFiles(directory);
      if (!files.hasNext()) continue;
      TodoDirNode dirNode = new TodoDirNode(myProject, directory, builder);
      if (!children.contains(dirNode)) {
        children.add(dirNode);
      }
    }
  }
protected void addDirsToChildren(@NotNull List<? extends VirtualFile> roots,
                                   @NotNull ArrayList<? super AbstractTreeNode<?>> children,
                                   @NotNull TodoTreeBuilder builder)