class MultiJson::OptionsCache::Store

def fetch(key, &block)
  @mutex.synchronize do
    return @cache[key] if @cache.key?(key)
  end
  value = yield
  @mutex.synchronize do
    if @cache.key?(key)
      # We ran into a race condition, keep the existing value
      @cache[key]
    else
      @cache.clear if @cache.size >= MAX_CACHE_SIZE
      @cache[key] = value
    end
  end
end

def initialize
  @cache = {}
  @mutex = Mutex.new
end

def reset
  @mutex.synchronize do
    @cache = {}
  end
end