runtime/__init__.py
author Edouard Tisserant <edouard.tisserant@gmail.com>
Wed, 05 Oct 2022 16:10:17 +0200
branchwxPython4
changeset 3617 c3aae4c95bc1
parent 2586 b89484560a97
child 3750 f62625418bff
permissions -rw-r--r--
Runtime: work around 1s delay added when using twisted reactor's callLater.

Since wxPython4, using wxReactor from non-main thread was producing
exceptions in wxWidget's C++ code. Then reactor.run() was called from
main thread, and runtime's worker was delegating calls to reactor
with callLater(0, callable).

While this worked perfectly with wxReactor, it did introduce an unexplained
1 second delay to each worker call when using nomal linux reactors
(i.e. without wxPython). As a workaround reactor runs in a thread when using
twisted without wxPython
#!/usr/bin/env python
# -*- coding: utf-8 -*-

from __future__ import absolute_import
from __future__ import print_function
import traceback
import sys

from runtime.Worker import worker
MainWorker = worker()

_PLCObjectSingleton = None


def GetPLCObjectSingleton():
    assert _PLCObjectSingleton is not None
    return _PLCObjectSingleton


def LogMessageAndException(msg, exp=None):
    if exp is None:
        exp = sys.exc_info()
    if _PLCObjectSingleton is not None:
        _PLCObjectSingleton.LogMessage(0, msg + '\n'.join(traceback.format_exception(*exp)))
    print(msg)
    traceback.print_exception(*exp)


def CreatePLCObjectSingleton(*args, **kwargs):
    global _PLCObjectSingleton
    from runtime.PLCObject import PLCObject  # noqa # pylint: disable=wrong-import-position
    _PLCObjectSingleton = PLCObject(*args, **kwargs)


def default_evaluator(tocall, *args, **kwargs):
    try:
        res = (tocall(*args, **kwargs), None)
    except Exception:
        res = (None, sys.exc_info())
    return res