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,
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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()