Staging
v0.5.1
v0.5.1
https://github.com/python/cpython
Revision 70cea58c84165460683b12e60331b4a90550e313 authored by Neal Norwitz on 28 March 2008, 06:34:03 UTC, committed by Neal Norwitz on 28 March 2008, 06:34:03 UTC
reliable, but I'm not convinced it is the right solution. We need to determine if this causes the test to hang on any platforms or do other bad things. Even if it gets the test to pass reliably, it might be that we want to fix this in socket. The socket returned from accept() is different on different platforms (inheriting attributes or not) and we might want to ensure that the attributes (at least blocking) is the same across all platforms.
1 parent 9fdfaaf
Tip revision: 70cea58c84165460683b12e60331b4a90550e313 authored by Neal Norwitz on 28 March 2008, 06:34:03 UTC
Bug 1503: Get the test to pass on OSX. This should make the test more
Bug 1503: Get the test to pass on OSX. This should make the test more
Tip revision: 70cea58
contextlib.py
"""Utilities for with-statement contexts. See PEP 343."""
import sys
__all__ = ["contextmanager", "nested", "closing"]
class GeneratorContextManager(object):
"""Helper for @contextmanager decorator."""
def __init__(self, gen):
self.gen = gen
def __enter__(self):
try:
return self.gen.next()
except StopIteration:
raise RuntimeError("generator didn't yield")
def __exit__(self, type, value, traceback):
if type is None:
try:
self.gen.next()
except StopIteration:
return
else:
raise RuntimeError("generator didn't stop")
else:
if value is None:
# Need to force instantiation so we can reliably
# tell if we get the same exception back
value = type()
try:
self.gen.throw(type, value, traceback)
raise RuntimeError("generator didn't stop after throw()")
except StopIteration, exc:
# Suppress the exception *unless* it's the same exception that
# was passed to throw(). This prevents a StopIteration
# raised inside the "with" statement from being suppressed
return exc is not value
except:
# only re-raise if it's *not* the exception that was
# passed to throw(), because __exit__() must not raise
# an exception unless __exit__() itself failed. But throw()
# has to raise the exception to signal propagation, so this
# fixes the impedance mismatch between the throw() protocol
# and the __exit__() protocol.
#
if sys.exc_info()[1] is not value:
raise
def contextmanager(func):
"""@contextmanager decorator.
Typical usage:
@contextmanager
def some_generator(<arguments>):
<setup>
try:
yield <value>
finally:
<cleanup>
This makes this:
with some_generator(<arguments>) as <variable>:
<body>
equivalent to this:
<setup>
try:
<variable> = <value>
<body>
finally:
<cleanup>
"""
def helper(*args, **kwds):
return GeneratorContextManager(func(*args, **kwds))
try:
helper.__name__ = func.__name__
helper.__doc__ = func.__doc__
helper.__dict__ = func.__dict__
except:
pass
return helper
@contextmanager
def nested(*managers):
"""Support multiple context managers in a single with-statement.
Code like this:
with nested(A, B, C) as (X, Y, Z):
<body>
is equivalent to this:
with A as X:
with B as Y:
with C as Z:
<body>
"""
exits = []
vars = []
exc = (None, None, None)
try:
for mgr in managers:
exit = mgr.__exit__
enter = mgr.__enter__
vars.append(enter())
exits.append(exit)
yield vars
except:
exc = sys.exc_info()
finally:
while exits:
exit = exits.pop()
try:
if exit(*exc):
exc = (None, None, None)
except:
exc = sys.exc_info()
if exc != (None, None, None):
# Don't rely on sys.exc_info() still containing
# the right information. Another exception may
# have been raised and caught by an exit method
raise exc[0], exc[1], exc[2]
class closing(object):
"""Context to automatically close something at the end of a block.
Code like this:
with closing(<module>.open(<arguments>)) as f:
<block>
is equivalent to this:
f = <module>.open(<arguments>)
try:
<block>
finally:
f.close()
"""
def __init__(self, thing):
self.thing = thing
def __enter__(self):
return self.thing
def __exit__(self, *exc_info):
self.thing.close()
Computing file changes ...
