Source code for pypdevs.realtime.threadingBackend
# Copyright 2014 Modelling, Simulation and Design Lab (MSDL) at
# McGill University and the University of Antwerp (http://msdl.cs.mcgill.ca/)
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import threading
[docs]class ThreadingBackend(object):
"""
Wrapper around the actual threading backend. It will also handle interrupts and the passing of them to the calling thread.
"""
[docs] def __init__(self, subsystem, args):
"""
Constructor
:param subsystem: string specifying the subsystem to use: python, tkinter or loop
:param args: all additional arguments that should be passed to the subsystem's constructor (must be a list)
"""
self.interrupted_value = None
self.value_lock = threading.Lock()
if subsystem == "python":
from pypdevs.realtime.threadingPython import ThreadingPython
self.subsystem = ThreadingPython(*args)
elif subsystem == "tkinter":
from pypdevs.realtime.threadingTkInter import ThreadingTkInter
self.subsystem = ThreadingTkInter(*args)
elif subsystem == "loop":
from pypdevs.realtime.threadingGameLoop import ThreadingGameLoop
self.subsystem = ThreadingGameLoop(*args)
else:
raise Exception("Realtime subsystem not found: " + str(subsystem))
[docs] def wait(self, time, func):
"""
A non-blocking call, which will call the *func* parameter after *time* seconds. It will use the provided backend to do this.
:param time: time to wait in seconds, a float is possible
:param func: the function to call after the time has passed
"""
self.subsystem.wait(time, func)
[docs] def interrupt(self, value):
"""
Interrupt a running wait call, overwriting any previous interrupts.
:param value: the value that interrupts
"""
self.interrupted_value = value
self.subsystem.interrupt()
[docs] def setInterrupt(self, value):
"""
Sets the value of the interrupt. This should not be used manually and is only required to prevent the asynchronous combo generator from making *interrrupt()* calls.
:param value: value with which the interrupt variable should be set
"""
with self.value_lock:
if self.interrupted_value is None:
self.interrupted_value = value
return True
else:
# The interrupt was already set, indicating a collision!
return False
[docs] def getInterrupt(self):
"""
Return the value of the interrupt and clear it internally.
:returns: the interrupt
"""
with self.value_lock:
val = self.interrupted_value
self.interrupted_value = None
return val
[docs] def step(self):
"""
Perform a step in the backend; only supported for the game loop backend.
"""
self.subsystem.step()