fibered_queue.rb

class FiberedQueue
  def initialize
    @queue = []
    @busy = false
  end

  def busy?
    !!@busy
  end

  def push &blk
    @queue << blk

    unless busy?
      begin
        @busy = Fiber.current
        while b = @queue.shift
          b.call
        end
      ensure
        @busy = false
      end
    end
  end
end

if __FILE__ == $0
  require 'fiber'
  require 'neverblock'
  require 'eventmachine'

  def sleep n
    f = Fiber.current
    EM.add_timer(n){ f.resume }
    Fiber.yield
  end

  pool = NB::Pool::FiberPool.new(5)
  queue = FiberedQueue.new

  EM.run{
    15.times do
      pool.spawn{
        queue.push{
          # queue.push{
            puts 'hi'; sleep 0.5; puts 'bye'
          # }
        }
      }
    end
  }
end