rainbows.git  about / heads / tags
Unicorn for sleepy apps and slow clients
blob f752a65b6692158d538e0edd71a56cb96c210a78 827 bytes (raw)
$ git show HEAD:lib/rainbows/fiber/queue.rb	# shows this blob on the CLI

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# -*- encoding: binary -*-
# :enddoc:
#
# a self-sufficient Queue implementation for Fiber-based concurrency
# models.  This requires no external scheduler, so it may be used with
# Revactor as well as FiberSpawn and FiberPool.
class Rainbows::Fiber::Queue < Struct.new(:queue, :waiters)
  def initialize(queue = [], waiters = [])
    # move elements of the Queue into an Array
    if queue.class.name == "Queue"
      queue = queue.length.times.map { queue.pop }
    end
    super queue, waiters
  end

  def shift
    # ah the joys of not having to deal with race conditions
    if queue.empty?
      waiters << Fiber.current
      Fiber.yield
    end
    queue.shift
  end

  def <<(obj)
    queue << obj
    blocked = waiters.shift and blocked.resume
    queue # not quite 100% compatible but no-one's looking :>
  end
end

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