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""" Central Registry for sys.exitfunc()-type functions
Copyright (c) 1997-2000, Marc-Andre Lemburg; mailto:mal@lemburg.com
See the documentation for further information on copyrights,
or contact the author. All Rights Reserved.
"""
import sys,traceback
__version__ = '3.2.8'
class ExitFunctionDispatcher:
""" Singleton that manages exit functions. These function will be
called upon system exit in reverse order of their registering.
"""
def __init__(self):
""" Install the dispatcher as sys.exitfunc()
"""
self.exitfunc_list = []
if hasattr(sys,'exitfunc'):
self.old_exitfunc = sys.exitfunc
else:
self.old_exitfunc = None
sys.exitfunc = self.exitfunc
def exitfunc(self,
write=sys.stderr.write,print_exc=traceback.print_exc,
stderr=sys.stderr):
""" This is the exitfunc that we install to dispatch the
processing to the registered other functions
"""
for f in self.exitfunc_list:
try:
f()
except:
write('Error while executing Exitfunction %s:\n' % f.__name__)
print_exc(10,stderr)
# Now that we're finished, call the previously installed exitfunc()
if self.old_exitfunc:
self.old_exitfunc()
def register(self,f,position=0):
""" Register f as exit function. These functions must not take
parameters.
- position = 0: register the function at the beginning of the
list; these functions get called before the functions already
in the list (default)
- position = -1: register the function at the end of the list;
the function will get called after all other functions
"""
if position < 0:
position = position + len(self.exitfunc_list) + 1
self.exitfunc_list.insert(position,f)
def deregister(self,f):
""" Remove the function f from the exitfunc list; if it is not
found, the error is silently ignored.
"""
try:
self.exitfunc_list.remove(f)
except:
pass
# Create the singleton
ExitFunctions = ExitFunctionDispatcher()
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