npyscreenreactor.py

#!/usr/bin/env python

# npyscreenreactory.py

# Inspired by pausingreactor.py and xmmsreactor.py

# npyscreen modifications
# Copyright (c) 2015 Mark Tearle <mark@tearle.com>

"""
This module provides wxPython event loop support for Twisted.

In order to use this support, simply do the following::

    |  import npyscreenreactor
    |  npyscreenreactor.install()

Then, when your root npyscreenApp has been created::

    | from twisted.internet import reactor
    | reactor.registerNpyscreenApp(yourApp)
    | reactor.run()

Then use twisted.internet APIs as usual. Stop the event loop using
reactor.stop(), not yourApp.ExitMainLoop().

IMPORTANT: tests will fail when run under this reactor. This is
expected and probably does not reflect on the reactor's ability to run
real applications.

Maintainer: Mark Tearle
"""

import sys

import Queue

from twisted.python import log, runtime
#from twisted.internet import _threadedselect
from twisted.internet import selectreactor

import npyscreen

#class NpyscreenReactor(_threadedselect.ThreadedSelectReactor):
class NpyscreenReactor(selectreactor.SelectReactor):
    """
    npyscreen reactor.

    npyscreen drives the event loop
    """
    def doIteration(self, timeout):
	selectreactor.SelectReactor.doIteration(self, timeout)

	# push event back on npyscreen queue
	self.npyscreenapp.queue_event(npyscreen.Event("_NPYSCREEN_REACTOR"))

    def registerNpyscreenApp(self, npyscreenapp):
        """
        Register npyscreen.StandardApp instance with the reactor.
        """
        self.npyscreenapp = npyscreenapp
	self.npyscreenapp.add_event_hander("_NPYSCREEN_REACTOR", self._twisted_events)

    def _twisted_events(self, event):
	self.doIteration(0)

    def _stopNpyscreen(self):
        """
        Stop the Npsycreen event loop if it hasn't already been stopped.

        Called during Twisted event loop shutdown.
        """
        if hasattr(self, "npyscreenapp"):
            self.npyscreenapp.setNextForm(None)

    def run(self):
        """
        Start the reactor.
        """
        # add cleanup events:
        self.addSystemEventTrigger("after", "shutdown", self._stopNpyscreen)

	# put event on queue to do twisted things 
	self.npyscreenapp.queue_event(npyscreen.Event("_NPYSCREEN_REACTOR"))

	#
        self.npyscreenapp.run()

def install():
    """
    Configure the twisted mainloop to be run inside the npyscreen mainloop.
    """
    reactor = NpyscreenReactor()
    from twisted.internet.main import installReactor
    installReactor(reactor)
    return reactor


__all__ = ['install']