module RuboCop::FileFinder

def self.root_level=(level)
  @root_level = level
end

def self.root_level?(path, stop_dir)
  (@root_level || stop_dir) == path.to_s
end

def find_file_upwards(filename, start_dir, stop_dir = nil)
  traverse_files_upwards(filename, start_dir, stop_dir) do |file|
    # minimize iteration for performance
    return file if file
  end
end

def find_last_file_upwards(filename, start_dir, stop_dir = nil)
  last_file = nil
  traverse_files_upwards(filename, start_dir, stop_dir) { |file| last_file = file }
  last_file
end

def traverse_files_upwards(filename, start_dir, stop_dir)
  Pathname.new(start_dir).expand_path.ascend do |dir|
    file = dir + filename
    yield(file.to_s) if file.exist?
    break if FileFinder.root_level?(dir, stop_dir)
  end
end