"""Enhanced Thread with support for return values and exception propagation."""
# Copyright (C) 2007 Canonical Ltd.
# Author: Martin Pitt <martin.pitt@ubuntu.com>
#
# 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. See http://www.gnu.org/copyleft/gpl.html for
# the full text of the license.
# pylint: disable=invalid-name
# pylint: enable=invalid-name
import sys
import threading
class REThread(threading.Thread):
"""Thread with return values and exception propagation."""
def __init__(self, group=None, target=None, name=None, args=(), kwargs=None):
"""Initialize Thread, identical to threading.Thread.__init__()."""
if kwargs is None:
kwargs = {}
threading.Thread.__init__(self, group, target, name, args, kwargs)
self.__target = target
self.__args = args
self.__kwargs = kwargs
self._retval = None
self._exception = None
def run(self):
"""Run target function, identical to threading.Thread.run()."""
if self.__target:
try:
self._retval = self.__target(*self.__args, **self.__kwargs)
except BaseException: # pylint: disable=broad-except
if sys: # pylint: disable=using-constant-test
self._exception = sys.exc_info()
def return_value(self):
"""Return value from target function.
This can only be called after the thread has finished, i. e. when
is_alive() is False and did not terminate with an exception.
"""
assert not self.is_alive()
assert not self._exception
return self._retval
def exc_info(self):
"""Return (type, value, traceback) of the exception caught in run()."""
return self._exception
def exc_raise(self):
"""Raise the exception caught in the thread.
Do nothing if no exception was caught.
"""
if self._exception:
raise self._exception[1].with_traceback(self._exception[2])
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