module GrpcKit
  class ControlQueue
    def initialize
      @event_stream = Queue.new
    end

    # Be nonblocking
    def pop
      if @event_stream.empty?
        nil
      else
        @event_stream.pop(true)
      end
    rescue ThreadError => _
      nil
    end

    def submit_response(id, headers)
      @event_stream.push([:submit_response, id, headers])
    end

    def submit_headers(id, headers)
      @event_stream.push([:submit_headers, id, headers])
    end

    def resume_data(id)
      @event_stream.push([:resume_data, id])
    end
  end
end