class PhusionPassenger::Rack::OutOfBandGc

def call(env)
  status, headers, body = @app.call(env)
  case @strategy
  when :counting
    @mutex.synchronize do
      @request_count += 1
      if @request_count == @frequency
        @request_count = 0
        headers['!~Request-OOB-Work'] = 'true'
      end
    end
  when :gctools_oobgc
    if GC::OOB.dry_run
      headers['!~Request-OOB-Work'] = 'true'
    end
  else
    raise "Unrecognized Out-Of-Band GC strategy #{@strategy.inspect}"
  end
  [status, headers, body]
end

def initialize(app, *args)
  @app = app
  if args.size == 0 || (args.size == 1 && args[0].is_a?(Hash))
    # OutOfBandGc.new(app, options = {})
    initialize_with_options(args[0] || {})
  else
    # OutOfBandGc.new(app, frequency, logger = nil)
    initialize_legacy(*args)
  end
end

def initialize_legacy(frequency, logger = nil)
  initialize_with_options(
    :strategy => :counting,
    :frequency => frequency,
    :logger => logger)
end

def initialize_with_options(options)
  @strategy = options[:strategy]
  @logger   = options[:logger]
  case @strategy
  when :counting
    @frequency     = options[:frequency]
    @request_count = 0
    @mutex         = Mutex.new
    if !@frequency || @frequency < 1
      raise ArgumentError, "The :frequency option must be a number that is at least 1."
    end
    ::PhusionPassenger.on_event(:oob_work) do
      t0 = Time.now
      disabled = GC.enable
      GC.start
      GC.disable if disabled
      @logger.info "Out Of Band GC finished in #{Time.now - t0} sec" if @logger
    end
  when :gctools_oobgc
    if !defined?(::GC::OOB)
      raise "To use the :gctools_oobgc strategy, " +
        "first add 'gem \"gctools\"' to your Gemfile, " +
        "then call 'require \"gctools/oobgc\"' and 'GC::OOB.setup' " +
        "before using the #{self.class.name} middleware."
    elsif !::GC::OOB.respond_to?(:dry_run)
      raise "To use the :gctools_oobgc strategy, you must use a sufficiently " +
        "recent version of the gctools gem. Please see this pull request: " +
        "https://github.com/tmm1/gctools/pull/5"
    elsif PhusionPassenger::App.options["spawn_method"] =~ /smart/
      # Using GC::OOB with 'smart' currently results in a segfault.
      raise "The :gctools_oobgc strategy cannot be used with the '" +
        PhusionPassenger::App.options["spawn_method"] + "' spawning method. " +
        "Please use 'direct'."
    end
    ::PhusionPassenger.on_event(:oob_work) do
      t0 = Time.now
      GC::OOB.run
      @logger.info "Out Of Band GC finished in #{Time.now - t0} sec" if @logger
    end
  when nil
    raise ArgumentError, "You must specify an Out-Of-Band GC strategy with the :strategy option."
  else
    raise ArgumentError, "Invalid Out-Of-Band GC strategy #{@strategy.inspect}"
  end
end