beremiz

Fixed deadlock when using Wx together with Twisted in runtime.

2019-01-29, Edouard Tisserant
2318a7cde101
Parents 6a7f92b84855
Children ef327451d067
Fixed deadlock when using Wx together with Twisted in runtime.
1 files changed, 25 insertions(+), 13 deletions(-)
  • +25 -13
    Beremiz_service.py
    • --- a/Beremiz_service.py Fri Jan 25 14:06:11 2019 +0100
    +++ b/Beremiz_service.py Tue Jan 29 09:14:47 2019 +0100
    @@ -30,7 +30,7 @@
    import sys
    import getopt
    import threading
    -from threading import Thread, Semaphore, Lock
    +from threading import Thread, Semaphore, Lock, currentThread
    import __builtin__
    from builtins import str as text
    from past.builtins import execfile
    @@ -414,10 +414,11 @@
    if havewx:
    reactor.registerWxApp(app)
    +twisted_reactor_thread_id = None
    +ui_thread = None
    +
    if havewx:
    wx_eval_lock = Semaphore(0)
    - # FIXME : beware wx mainloop is _not_ running in main thread
    - # main_thread = currentThread()
    def statuschangeTskBar(status):
    wx.CallAfter(taskbar_instance.UpdateIcon, status)
    @@ -430,15 +431,23 @@
    wx_eval_lock.release()
    def evaluator(tocall, *args, **kwargs):
    - # FIXME : should implement anti-deadlock
    - # if main_thread == currentThread():
    - # # avoid dead lock if called from the wx mainloop
    - # return default_evaluator(tocall, *args, **kwargs)
    - # else:
    - o = type('', (object,), dict(call=(tocall, args, kwargs), res=None))
    - wx.CallAfter(wx_evaluator, o)
    - wx_eval_lock.acquire()
    - return o.res
    + # To prevent deadlocks, check if current thread is not one of the UI
    + # UI threads can be either the one from WX main loop or
    + # worker thread from twisted "threadselect" reactor
    + current_id = currentThread().ident
    + if ui_thread is not None \
    + and ui_thread.ident != current_id \
    + and (not havetwisted or (
    + twisted_reactor_thread_id is not None
    + and twisted_reactor_thread_id != current_id)):
    +
    + o = type('', (object,), dict(call=(tocall, args, kwargs), res=None))
    + wx.CallAfter(wx_evaluator, o)
    + wx_eval_lock.acquire()
    + return o.res
    + else:
    + # avoid dead lock if called from the wx mainloop
    + return default_evaluator(tocall, *args, **kwargs)
    else:
    evaluator = default_evaluator
    @@ -560,7 +569,10 @@
    # This order ui loop to unblock main thread when ready.
    if havetwisted:
    - reactor.callLater(0, ui_thread_started.release)
    + def signal_uithread_started():
    + twisted_reactor_thread_id = currentThread().ident
    + ui_thread_started.release()
    + reactor.callLater(0, signal_uithread_started)
    else:
    wx.CallAfter(ui_thread_started.release)