class ElasticAPM::Util::LruCache

def [](key)
  @mutex.synchronize do
    val = @data[key]
    return unless val
    add(key, val)
    val
  end
end

def []=(key, val)
  @mutex.synchronize do
    add(key, val)
  end
end

def add(key, val)
  @data.delete(key)
  @data[key] = val
  return unless @data.length > @max_size
  @data.delete(@data.first[0])
end

def initialize(max_size = 512, &block)
  @max_size = max_size
  @data = Hash.new(&block)
  @mutex = Mutex.new
end

def length
  @data.length
end

def to_a
  @data.to_a
end