class FDB::DirectoryLayer

def create_or_open_internal(db_or_tr, path, allow_create, allow_open, options={})
  defaults = { :layer => '', :prefix => nil }
  options = defaults.merge(options)
  if !options[:prefix].nil? and allow_open and allow_create
    raise ArgumentError, 'Cannot specify a prefix when calling create_or_open.'
  end
  if !options[:prefix].nil? and !@allow_manual_prefixes
    if @path.length == 0
      raise ArgumentError, 'Cannot specify a prefix unless manual prefixes are enabled.'
    else
      raise ArgumentError, 'Cannot specify a prefix in a partition.'
    end
  end
  db_or_tr.transact do |tr|
    check_version(tr, false)
    path = to_unicode_path(path)
    raise ArgumentError, 'The root directory cannot be opened.' if path.length == 0
    existing_node = find(tr, path).prefetch_metadata(tr)
    
    if existing_node.exists?
      if existing_node.is_in_partition?
        subpath = existing_node.get_partition_subpath
        existing_node.get_contents(self).directory_layer.create_or_open_internal(tr, subpath, allow_create, allow_open, options)
      else
        raise ArgumentError, 'The directory already exists.' unless allow_open
        open_directory(path, options, existing_node)
      end
    else
      raise ArgumentError, 'The directory does not exist.' unless allow_create
      create_directory(tr, path, options)
    end
  end
end