frappy/secop/lib/multievent.py
Markus Zolliker 8f7fb1e45b improve handling of module init methods
- complain when super call is omitted (this is a common programming
  error in Mixins)
- redesign waiting mechanism for startup

+ rename MultiEvent method 'setfunc' to 'get_trigger'

Change-Id: Ica27a75597321f2571a604a7a55448cffb1bec5e
Reviewed-on: https://forge.frm2.tum.de/review/c/sine2020/secop/playground/+/27369
Tested-by: Jenkins Automated Tests <pedersen+jenkins@frm2.tum.de>
Reviewed-by: Enrico Faulhaber <enrico.faulhaber@frm2.tum.de>
Reviewed-by: Markus Zolliker <markus.zolliker@psi.ch>
2022-01-07 17:41:59 +01:00

119 lines
3.6 KiB
Python

# -*- coding: utf-8 -*-
# *****************************************************************************
#
# This program is free software; you can redistribute it and/or modify it under
# the terms of the GNU General Public License as published by the Free Software
# Foundation; either version 2 of the License, or (at your option) any later
# version.
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
# details.
#
# You should have received a copy of the GNU General Public License along with
# this program; if not, write to the Free Software Foundation, Inc.,
# 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
#
# Module authors:
# Markus Zolliker <markus.zolliker@psi.ch>
#
# *****************************************************************************
import threading
import time
ETERNITY = 1e99
class _SingleEvent:
"""Single Event
remark: :meth:`wait` is not implemented on purpose
"""
def __init__(self, multievent, timeout, name=None):
self.multievent = multievent
self.multievent.clear_(self)
self.name = name
if timeout is None:
self.deadline = ETERNITY
else:
self.deadline = time.monotonic() + timeout
def clear(self):
self.multievent.clear_(self)
def set(self):
self.multievent.set_(self)
def is_set(self):
return self in self.multievent.events
class MultiEvent(threading.Event):
"""Class implementing multi event objects."""
def __init__(self, default_timeout=None):
self.events = set()
self._lock = threading.Lock()
self.default_timeout = default_timeout or None # treat 0 as None
self.name = None # default event name
super().__init__()
def new(self, timeout=None, name=None):
"""create a single event like object"""
return _SingleEvent(self, timeout or self.default_timeout,
name or self.name or '<unnamed>')
def set(self):
raise ValueError('a multievent must not be set directly')
def clear(self):
raise ValueError('a multievent must not be cleared directly')
def is_set(self):
return not self.events
def set_(self, event):
"""internal: remove event from the event list"""
with self._lock:
self.events.discard(event)
if self.events:
return
super().set()
def clear_(self, event):
"""internal: add event to the event list"""
with self._lock:
self.events.add(event)
super().clear()
def deadline(self):
deadline = 0
for event in self.events:
deadline = max(event.deadline, deadline)
return None if deadline == ETERNITY else deadline
def wait(self, timeout=None):
"""wait for all events being set or timed out"""
if not self.events: # do not wait if events are empty
return True
deadline = self.deadline()
if deadline is not None:
deadline -= time.monotonic()
timeout = deadline if timeout is None else min(deadline, timeout)
if timeout <= 0:
return False
return super().wait(timeout)
def waiting_for(self):
return set(event.name for event in self.events)
def get_trigger(self, timeout=None, name=None):
"""create a new single event and return its set method
as a convenience method
"""
return self.new(timeout, name).set