kivy/kivy/support.py

108 lines
3.6 KiB
Python

'''
Support
=======
Activate other framework/toolkit inside our event loop
'''
__all__ = ('install_gobject_iteration', 'install_twisted_reactor')
def install_gobject_iteration():
'''Import and install gobject context iteration inside our event loop.
This is used as soon as gobject is used (like gstreamer)
'''
from kivy.clock import Clock
import gobject
if hasattr(gobject, '_gobject_already_installed'):
# already installed, don't do it twice.
return
gobject._gobject_already_installed = True
# get gobject mainloop / context
loop = gobject.MainLoop()
gobject.threads_init()
context = loop.get_context()
# schedule the iteration each frame
def _gobject_iteration(*largs):
# XXX we need to loop over context here, otherwise, we might have a lag.
loop = 0
while context.pending() and loop < 10:
context.iteration(False)
loop += 1
Clock.schedule_interval(_gobject_iteration, 0)
def install_twisted_reactor(**kwargs):
'''Installs a threaded twisted reactor, which will schedule one
reactor iteration before the next frame only when twisted needs
to do some work.
any arguments or keyword arguments passed to this function will be
passed on the the threadedselect reactors interleave function, these
are the arguments one would usually pass to twisted's reactor.startRunning
Unlike the default twisted reactor, the installed reactor will not handle
any signals unnless you set the 'installSignalHandlers' keyword argument
to 1 explicitly. This is done to allow kivy to handle teh signals as
usual, unless you specifically want the twisted reactor to handle the
signals (e.g. SIGINT).'''
import twisted
# prevent installing more than once
if hasattr(twisted, '_kivy_twisted_reactor_installed'):
return
twisted._kivy_twisted_reactor_installed = True
# dont let twisted handle signals, unless specifically requested
kwargs.setdefault('installSignalHandlers', 0)
# install threaded-select reactor, to use with own event loop
from twisted.internet import _threadedselect
_threadedselect.install()
# now we can import twisted reactor as usual
from twisted.internet import reactor
from collections import deque
from kivy.base import EventLoop
from kivy.logger import Logger
from kivy.clock import Clock
# will hold callbacks to twisted callbacks
q = deque()
# twisted will call the wake function when it needsto do work
def reactor_wake(twisted_loop_next):
Logger.trace("Support: twisted wakeup call to schedule task")
q.append(twisted_loop_next)
# called every frame, to process the reactors work in main thread
def reactor_work(*args):
Logger.trace("Support: processing twisted task queue")
while len(q):
q.popleft()()
# start the reactor, by telling twisted how to wake, and process
def reactor_start(*args):
Logger.info("Support: Starting twisted reactor")
reactor.interleave(reactor_wake, **kwargs)
Clock.schedule_interval(reactor_work, 0)
# make sure twisted reactor is shutdown if eventloop exists
def reactor_stop(*args):
'''will shutdown the twisted reactor main loop
'''
if reactor.threadpool:
Logger.info("Support: Stooping twisted threads")
reactor.threadpool.stop()
Logger.info("Support: Shutting down twisted reactor")
reactor._mainLoopShutdown()
# start and stop teh reactor along with kivy EventLoop
EventLoop.bind(on_start=reactor_start)
EventLoop.bind(on_stop=reactor_stop)