splitd.py

from zope.interface import Interface
from twisted.python.components import proxyForInterface


class IResolver(Interface):
    def callback(result):
        pass

    def errback(reason):
        pass


class IPromise(Interface):
    def addCallback(*args, **kwargs):
        pass

    def addCallbacks(*args, **kwargs):
        pass

    def addBoth(*args, **kwargs):
        pass

    def addErrback(*args, **kwargs):
        pass

    def cancel():
        pass


class Promise(proxyForInterface(IPromise)):
    pass


class Resolver(proxyForInterface(IResolver)):
    pass


def splitDeferred(d):
    return (Promise(d), Resolver(d))


if __name__ == '__main__':
    from twisted.internet.defer import Deferred
    import splitd

    d = Deferred()
    p, r = splitd.splitDeferred(d)

    def _print(result):
        print result

    p.addCallback(_print)

    r.callback('foo')

    d2 = Deferred()
    p2, r2 = splitDeferred(d2)

    p2.callback('foo')