# -*- encoding: binary -*-
require 'rainbows/fiber'

# A Fiber-based concurrency model for Ruby 1.9.  This uses a pool of
# Fibers to handle client IO to run the application and the root Fiber
# for scheduling and connection acceptance.
#
# This concurrency model is difficult to use with existing applications,
# lacks third-party support, and is thus NOT recommended.
#
# The pool size is equal to the number of +worker_connections+.
# Compared to the ThreadPool model, Fibers are very cheap in terms of
# memory usage so you can have more active connections.  This model
# supports a streaming "rack.input" with lightweight concurrency.
# Applications are strongly advised to wrap all slow IO objects
# (sockets, pipes) using the Rainbows::Fiber::IO class whenever
# possible.
module Rainbows::FiberPool
  include Rainbows::Fiber::Base

  def worker_loop(worker) # :nodoc:
    init_worker_process(worker)
    pool = []
    worker_connections.times {
      Fiber.new {
        process(Fiber.yield) while pool << Fiber.current
      }.resume # resume to hit Fiber.yield so it waits on a client
    }
    Rainbows::Fiber::Base.setup(self.class, app)

    begin
      schedule do |l|
        fib = pool.shift or break # let another worker process take it
        if io = l.kgio_tryaccept
          fib.resume(io)
        else
          pool << fib
        end
      end
    rescue => e
      Rainbows::Error.listen_loop(e)
    end while Rainbows.cur_alive
  end
end
