class Rake::ThreadPool

def process_queue_item      #:nodoc:
  return false if @queue.empty?
  # Even though we just asked if the queue was empty, it
  # still could have had an item which by this statement
  # is now gone. For this reason we pass true to Queue#deq
  # because we will sleep indefinitely if it is empty.
  promise = @queue.deq(true)
  stat :dequeued, item_id: promise.object_id
  promise.work
  return true
rescue ThreadError # this means the queue is empty
  false
end