# File actionview/lib/action_view/cache_expiry.rb, line 33
def initialize(watcher:, &block)
  @watched_dirs = nil
  @watcher_class = watcher
  @watcher = nil
  @mutex = Mutex.new
  @block = block
end

# File actionview/lib/action_view/cache_expiry.rb, line 41
def execute_if_updated
  @mutex.synchronize do
    watched_dirs = dirs_to_watch
    return if watched_dirs.empty?

    if watched_dirs != @watched_dirs
      @watched_dirs = watched_dirs
      @watcher = @watcher_class.new([], watched_dirs, &@block)
      @watcher.execute
    else
      @watcher.execute_if_updated
    end
  end
end