Method: Win32::Daemon#mainloop

Defined in:
lib/win32/daemon.rb

#mainloop ⇒ Object

This is the method that actually puts your code into a loop and allows it to run as a service. The code that is actually run while in the mainloop is what you defined in your own Daemon#service_main method.



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# File 'lib/win32/daemon.rb', line 218

def mainloop
  @@waiting_control_code = IDLE_CONTROL_CODE
  @@dwServiceState = 0

  # Redirect STDIN, STDOUT and STDERR to the NUL device if they're still
  # associated with a tty. This helps newbs avoid Errno::EBADF errors.
  STDIN.reopen("NUL") if STDIN.isatty
  STDOUT.reopen("NUL") if STDOUT.isatty
  STDERR.reopen("NUL") if STDERR.isatty

  # Calling init here so that init failures never even tries to start the
  # service. Of course that means that init methods must be very quick
  # because the SCM will be receiving no START_PENDING messages while
  # init's running.
  #
  # TODO: Fix?
  service_init if respond_to?("service_init")

  # Create the event to signal the service to start.
  @@hStartEvent = CreateEvent(nil, 1, 0, nil)

  if @@hStartEvent == 0
    raise SystemCallError.new("CreateEvent", FFI.errno)
  end

  # Create the event to signal the service to stop.
  @@hStopEvent = CreateEvent(nil, 1, 0, nil)

  if @@hStopEvent == 0
    raise SystemCallError.new("CreateEvent", FFI.errno)
  end

  # Create the event to signal the service that stop has completed
  @@hStopCompletedEvent = CreateEvent(nil, 1, 0, nil)

  if @@hStopCompletedEvent == 0
    raise SystemCallError.new("CreateEvent", FFI.errno)
  end

  hThread = CreateThread(nil, 0, ThreadProc, Service_Main, 0, nil)

  if hThread == 0
    raise SystemCallError.new("CreateThread", FFI.errno)
  end

  events = FFI::MemoryPointer.new(:pointer, 2)
  events.put_pointer(0, FFI::Pointer.new(hThread))
  events.put_pointer(FFI::Pointer.size, FFI::Pointer.new(@@hStartEvent))

  while (index = WaitForMultipleObjects(2, events, 0, 1000)) == WAIT_TIMEOUT
  end

  if index == WAIT_FAILED
    raise SystemCallError.new("WaitForMultipleObjects", FFI.errno)
  end

  # The thread exited, so the show is off.
  if index == WAIT_OBJECT_0
    raise "Service_Main thread exited abnormally"
  end

  thr = Thread.new do
    begin
      while WaitForSingleObject(@@hStopEvent, 1000) == WAIT_TIMEOUT
        # Check to see if anything interesting has been signaled
        case @@waiting_control_code
          when SERVICE_CONTROL_PAUSE
            service_pause if respond_to?("service_pause")
          when SERVICE_CONTROL_CONTINUE
            service_resume if respond_to?("service_resume")
          when SERVICE_CONTROL_INTERROGATE
            service_interrogate if respond_to?("service_interrogate")
          when SERVICE_CONTROL_SHUTDOWN
            service_shutdown if respond_to?("service_shutdown")
          when SERVICE_CONTROL_PARAMCHANGE
            service_paramchange if respond_to?("service_paramchange")
          when SERVICE_CONTROL_NETBINDADD
            service_netbindadd if respond_to?("service_netbindadd")
          when SERVICE_CONTROL_NETBINDREMOVE
            service_netbindremove if respond_to?("service_netbindremove")
          when SERVICE_CONTROL_NETBINDENABLE
            service_netbindenable if respond_to?("service_netbindenable")
          when SERVICE_CONTROL_NETBINDDISABLE
            service_netbinddisable if respond_to?("service_netbinddisable")
        end

        # handle user defined control codes
        if @@waiting_control_code >= 128 && @@waiting_control_code <= 255
          if respond_to?("service_user_defined_control")
            service_user_defined_control(@@waiting_control_code)
          end
        end

        @@waiting_control_code = IDLE_CONTROL_CODE
      end

      service_stop if respond_to?("service_stop")
    ensure
      SetEvent(@@hStopCompletedEvent)
    end
  end

  if respond_to?("service_main")
    service_main(*@@Argv)
  end

  thr.join
end