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authornkozlovskiy <nmk@ydb.tech>2023-09-29 12:24:06 +0300
committernkozlovskiy <nmk@ydb.tech>2023-09-29 12:41:34 +0300
commite0e3e1717e3d33762ce61950504f9637a6e669ed (patch)
treebca3ff6939b10ed60c3d5c12439963a1146b9711 /contrib/tools/python3/src/Lib/contextlib.py
parent38f2c5852db84c7b4d83adfcb009eb61541d1ccd (diff)
downloadydb-e0e3e1717e3d33762ce61950504f9637a6e669ed.tar.gz
add ydb deps
Diffstat (limited to 'contrib/tools/python3/src/Lib/contextlib.py')
-rw-r--r--contrib/tools/python3/src/Lib/contextlib.py779
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diff --git a/contrib/tools/python3/src/Lib/contextlib.py b/contrib/tools/python3/src/Lib/contextlib.py
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+++ b/contrib/tools/python3/src/Lib/contextlib.py
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+"""Utilities for with-statement contexts. See PEP 343."""
+import abc
+import os
+import sys
+import _collections_abc
+from collections import deque
+from functools import wraps
+from types import MethodType, GenericAlias
+
+__all__ = ["asynccontextmanager", "contextmanager", "closing", "nullcontext",
+ "AbstractContextManager", "AbstractAsyncContextManager",
+ "AsyncExitStack", "ContextDecorator", "ExitStack",
+ "redirect_stdout", "redirect_stderr", "suppress", "aclosing",
+ "chdir"]
+
+
+class AbstractContextManager(abc.ABC):
+
+ """An abstract base class for context managers."""
+
+ __class_getitem__ = classmethod(GenericAlias)
+
+ def __enter__(self):
+ """Return `self` upon entering the runtime context."""
+ return self
+
+ @abc.abstractmethod
+ def __exit__(self, exc_type, exc_value, traceback):
+ """Raise any exception triggered within the runtime context."""
+ return None
+
+ @classmethod
+ def __subclasshook__(cls, C):
+ if cls is AbstractContextManager:
+ return _collections_abc._check_methods(C, "__enter__", "__exit__")
+ return NotImplemented
+
+
+class AbstractAsyncContextManager(abc.ABC):
+
+ """An abstract base class for asynchronous context managers."""
+
+ __class_getitem__ = classmethod(GenericAlias)
+
+ async def __aenter__(self):
+ """Return `self` upon entering the runtime context."""
+ return self
+
+ @abc.abstractmethod
+ async def __aexit__(self, exc_type, exc_value, traceback):
+ """Raise any exception triggered within the runtime context."""
+ return None
+
+ @classmethod
+ def __subclasshook__(cls, C):
+ if cls is AbstractAsyncContextManager:
+ return _collections_abc._check_methods(C, "__aenter__",
+ "__aexit__")
+ return NotImplemented
+
+
+class ContextDecorator(object):
+ "A base class or mixin that enables context managers to work as decorators."
+
+ def _recreate_cm(self):
+ """Return a recreated instance of self.
+
+ Allows an otherwise one-shot context manager like
+ _GeneratorContextManager to support use as
+ a decorator via implicit recreation.
+
+ This is a private interface just for _GeneratorContextManager.
+ See issue #11647 for details.
+ """
+ return self
+
+ def __call__(self, func):
+ @wraps(func)
+ def inner(*args, **kwds):
+ with self._recreate_cm():
+ return func(*args, **kwds)
+ return inner
+
+
+class AsyncContextDecorator(object):
+ "A base class or mixin that enables async context managers to work as decorators."
+
+ def _recreate_cm(self):
+ """Return a recreated instance of self.
+ """
+ return self
+
+ def __call__(self, func):
+ @wraps(func)
+ async def inner(*args, **kwds):
+ async with self._recreate_cm():
+ return await func(*args, **kwds)
+ return inner
+
+
+class _GeneratorContextManagerBase:
+ """Shared functionality for @contextmanager and @asynccontextmanager."""
+
+ def __init__(self, func, args, kwds):
+ self.gen = func(*args, **kwds)
+ self.func, self.args, self.kwds = func, args, kwds
+ # Issue 19330: ensure context manager instances have good docstrings
+ doc = getattr(func, "__doc__", None)
+ if doc is None:
+ doc = type(self).__doc__
+ self.__doc__ = doc
+ # Unfortunately, this still doesn't provide good help output when
+ # inspecting the created context manager instances, since pydoc
+ # currently bypasses the instance docstring and shows the docstring
+ # for the class instead.
+ # See http://bugs.python.org/issue19404 for more details.
+
+ def _recreate_cm(self):
+ # _GCMB instances are one-shot context managers, so the
+ # CM must be recreated each time a decorated function is
+ # called
+ return self.__class__(self.func, self.args, self.kwds)
+
+
+class _GeneratorContextManager(
+ _GeneratorContextManagerBase,
+ AbstractContextManager,
+ ContextDecorator,
+):
+ """Helper for @contextmanager decorator."""
+
+ def __enter__(self):
+ # do not keep args and kwds alive unnecessarily
+ # they are only needed for recreation, which is not possible anymore
+ del self.args, self.kwds, self.func
+ try:
+ return next(self.gen)
+ except StopIteration:
+ raise RuntimeError("generator didn't yield") from None
+
+ def __exit__(self, typ, value, traceback):
+ if typ is None:
+ try:
+ next(self.gen)
+ except StopIteration:
+ return False
+ 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 = typ()
+ try:
+ self.gen.throw(typ, value, traceback)
+ except StopIteration as exc:
+ # Suppress StopIteration *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 RuntimeError as exc:
+ # Don't re-raise the passed in exception. (issue27122)
+ if exc is value:
+ exc.__traceback__ = traceback
+ return False
+ # Avoid suppressing if a StopIteration exception
+ # was passed to throw() and later wrapped into a RuntimeError
+ # (see PEP 479 for sync generators; async generators also
+ # have this behavior). But do this only if the exception wrapped
+ # by the RuntimeError is actually Stop(Async)Iteration (see
+ # issue29692).
+ if (
+ isinstance(value, StopIteration)
+ and exc.__cause__ is value
+ ):
+ value.__traceback__ = traceback
+ return False
+ raise
+ except BaseException as exc:
+ # 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 exc is not value:
+ raise
+ exc.__traceback__ = traceback
+ return False
+ raise RuntimeError("generator didn't stop after throw()")
+
+class _AsyncGeneratorContextManager(
+ _GeneratorContextManagerBase,
+ AbstractAsyncContextManager,
+ AsyncContextDecorator,
+):
+ """Helper for @asynccontextmanager decorator."""
+
+ async def __aenter__(self):
+ # do not keep args and kwds alive unnecessarily
+ # they are only needed for recreation, which is not possible anymore
+ del self.args, self.kwds, self.func
+ try:
+ return await anext(self.gen)
+ except StopAsyncIteration:
+ raise RuntimeError("generator didn't yield") from None
+
+ async def __aexit__(self, typ, value, traceback):
+ if typ is None:
+ try:
+ await anext(self.gen)
+ except StopAsyncIteration:
+ return False
+ 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 = typ()
+ try:
+ await self.gen.athrow(typ, value, traceback)
+ except StopAsyncIteration as exc:
+ # Suppress StopIteration *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 RuntimeError as exc:
+ # Don't re-raise the passed in exception. (issue27122)
+ if exc is value:
+ exc.__traceback__ = traceback
+ return False
+ # Avoid suppressing if a Stop(Async)Iteration exception
+ # was passed to athrow() and later wrapped into a RuntimeError
+ # (see PEP 479 for sync generators; async generators also
+ # have this behavior). But do this only if the exception wrapped
+ # by the RuntimeError is actually Stop(Async)Iteration (see
+ # issue29692).
+ if (
+ isinstance(value, (StopIteration, StopAsyncIteration))
+ and exc.__cause__ is value
+ ):
+ value.__traceback__ = traceback
+ return False
+ raise
+ except BaseException as exc:
+ # 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 exc is not value:
+ raise
+ exc.__traceback__ = traceback
+ return False
+ raise RuntimeError("generator didn't stop after athrow()")
+
+
+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>
+ """
+ @wraps(func)
+ def helper(*args, **kwds):
+ return _GeneratorContextManager(func, args, kwds)
+ return helper
+
+
+def asynccontextmanager(func):
+ """@asynccontextmanager decorator.
+
+ Typical usage:
+
+ @asynccontextmanager
+ async def some_async_generator(<arguments>):
+ <setup>
+ try:
+ yield <value>
+ finally:
+ <cleanup>
+
+ This makes this:
+
+ async with some_async_generator(<arguments>) as <variable>:
+ <body>
+
+ equivalent to this:
+
+ <setup>
+ try:
+ <variable> = <value>
+ <body>
+ finally:
+ <cleanup>
+ """
+ @wraps(func)
+ def helper(*args, **kwds):
+ return _AsyncGeneratorContextManager(func, args, kwds)
+ return helper
+
+
+class closing(AbstractContextManager):
+ """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()
+
+
+class aclosing(AbstractAsyncContextManager):
+ """Async context manager for safely finalizing an asynchronously cleaned-up
+ resource such as an async generator, calling its ``aclose()`` method.
+
+ Code like this:
+
+ async with aclosing(<module>.fetch(<arguments>)) as agen:
+ <block>
+
+ is equivalent to this:
+
+ agen = <module>.fetch(<arguments>)
+ try:
+ <block>
+ finally:
+ await agen.aclose()
+
+ """
+ def __init__(self, thing):
+ self.thing = thing
+ async def __aenter__(self):
+ return self.thing
+ async def __aexit__(self, *exc_info):
+ await self.thing.aclose()
+
+
+class _RedirectStream(AbstractContextManager):
+
+ _stream = None
+
+ def __init__(self, new_target):
+ self._new_target = new_target
+ # We use a list of old targets to make this CM re-entrant
+ self._old_targets = []
+
+ def __enter__(self):
+ self._old_targets.append(getattr(sys, self._stream))
+ setattr(sys, self._stream, self._new_target)
+ return self._new_target
+
+ def __exit__(self, exctype, excinst, exctb):
+ setattr(sys, self._stream, self._old_targets.pop())
+
+
+class redirect_stdout(_RedirectStream):
+ """Context manager for temporarily redirecting stdout to another file.
+
+ # How to send help() to stderr
+ with redirect_stdout(sys.stderr):
+ help(dir)
+
+ # How to write help() to a file
+ with open('help.txt', 'w') as f:
+ with redirect_stdout(f):
+ help(pow)
+ """
+
+ _stream = "stdout"
+
+
+class redirect_stderr(_RedirectStream):
+ """Context manager for temporarily redirecting stderr to another file."""
+
+ _stream = "stderr"
+
+
+class suppress(AbstractContextManager):
+ """Context manager to suppress specified exceptions
+
+ After the exception is suppressed, execution proceeds with the next
+ statement following the with statement.
+
+ with suppress(FileNotFoundError):
+ os.remove(somefile)
+ # Execution still resumes here if the file was already removed
+ """
+
+ def __init__(self, *exceptions):
+ self._exceptions = exceptions
+
+ def __enter__(self):
+ pass
+
+ def __exit__(self, exctype, excinst, exctb):
+ # Unlike isinstance and issubclass, CPython exception handling
+ # currently only looks at the concrete type hierarchy (ignoring
+ # the instance and subclass checking hooks). While Guido considers
+ # that a bug rather than a feature, it's a fairly hard one to fix
+ # due to various internal implementation details. suppress provides
+ # the simpler issubclass based semantics, rather than trying to
+ # exactly reproduce the limitations of the CPython interpreter.
+ #
+ # See http://bugs.python.org/issue12029 for more details
+ return exctype is not None and issubclass(exctype, self._exceptions)
+
+
+class _BaseExitStack:
+ """A base class for ExitStack and AsyncExitStack."""
+
+ @staticmethod
+ def _create_exit_wrapper(cm, cm_exit):
+ return MethodType(cm_exit, cm)
+
+ @staticmethod
+ def _create_cb_wrapper(callback, /, *args, **kwds):
+ def _exit_wrapper(exc_type, exc, tb):
+ callback(*args, **kwds)
+ return _exit_wrapper
+
+ def __init__(self):
+ self._exit_callbacks = deque()
+
+ def pop_all(self):
+ """Preserve the context stack by transferring it to a new instance."""
+ new_stack = type(self)()
+ new_stack._exit_callbacks = self._exit_callbacks
+ self._exit_callbacks = deque()
+ return new_stack
+
+ def push(self, exit):
+ """Registers a callback with the standard __exit__ method signature.
+
+ Can suppress exceptions the same way __exit__ method can.
+ Also accepts any object with an __exit__ method (registering a call
+ to the method instead of the object itself).
+ """
+ # We use an unbound method rather than a bound method to follow
+ # the standard lookup behaviour for special methods.
+ _cb_type = type(exit)
+
+ try:
+ exit_method = _cb_type.__exit__
+ except AttributeError:
+ # Not a context manager, so assume it's a callable.
+ self._push_exit_callback(exit)
+ else:
+ self._push_cm_exit(exit, exit_method)
+ return exit # Allow use as a decorator.
+
+ def enter_context(self, cm):
+ """Enters the supplied context manager.
+
+ If successful, also pushes its __exit__ method as a callback and
+ returns the result of the __enter__ method.
+ """
+ # We look up the special methods on the type to match the with
+ # statement.
+ cls = type(cm)
+ try:
+ _enter = cls.__enter__
+ _exit = cls.__exit__
+ except AttributeError:
+ raise TypeError(f"'{cls.__module__}.{cls.__qualname__}' object does "
+ f"not support the context manager protocol") from None
+ result = _enter(cm)
+ self._push_cm_exit(cm, _exit)
+ return result
+
+ def callback(self, callback, /, *args, **kwds):
+ """Registers an arbitrary callback and arguments.
+
+ Cannot suppress exceptions.
+ """
+ _exit_wrapper = self._create_cb_wrapper(callback, *args, **kwds)
+
+ # We changed the signature, so using @wraps is not appropriate, but
+ # setting __wrapped__ may still help with introspection.
+ _exit_wrapper.__wrapped__ = callback
+ self._push_exit_callback(_exit_wrapper)
+ return callback # Allow use as a decorator
+
+ def _push_cm_exit(self, cm, cm_exit):
+ """Helper to correctly register callbacks to __exit__ methods."""
+ _exit_wrapper = self._create_exit_wrapper(cm, cm_exit)
+ self._push_exit_callback(_exit_wrapper, True)
+
+ def _push_exit_callback(self, callback, is_sync=True):
+ self._exit_callbacks.append((is_sync, callback))
+
+
+# Inspired by discussions on http://bugs.python.org/issue13585
+class ExitStack(_BaseExitStack, AbstractContextManager):
+ """Context manager for dynamic management of a stack of exit callbacks.
+
+ For example:
+ with ExitStack() as stack:
+ files = [stack.enter_context(open(fname)) for fname in filenames]
+ # All opened files will automatically be closed at the end of
+ # the with statement, even if attempts to open files later
+ # in the list raise an exception.
+ """
+
+ def __enter__(self):
+ return self
+
+ def __exit__(self, *exc_details):
+ received_exc = exc_details[0] is not None
+
+ # We manipulate the exception state so it behaves as though
+ # we were actually nesting multiple with statements
+ frame_exc = sys.exc_info()[1]
+ def _fix_exception_context(new_exc, old_exc):
+ # Context may not be correct, so find the end of the chain
+ while 1:
+ exc_context = new_exc.__context__
+ if exc_context is None or exc_context is old_exc:
+ # Context is already set correctly (see issue 20317)
+ return
+ if exc_context is frame_exc:
+ break
+ new_exc = exc_context
+ # Change the end of the chain to point to the exception
+ # we expect it to reference
+ new_exc.__context__ = old_exc
+
+ # Callbacks are invoked in LIFO order to match the behaviour of
+ # nested context managers
+ suppressed_exc = False
+ pending_raise = False
+ while self._exit_callbacks:
+ is_sync, cb = self._exit_callbacks.pop()
+ assert is_sync
+ try:
+ if cb(*exc_details):
+ suppressed_exc = True
+ pending_raise = False
+ exc_details = (None, None, None)
+ except:
+ new_exc_details = sys.exc_info()
+ # simulate the stack of exceptions by setting the context
+ _fix_exception_context(new_exc_details[1], exc_details[1])
+ pending_raise = True
+ exc_details = new_exc_details
+ if pending_raise:
+ try:
+ # bare "raise exc_details[1]" replaces our carefully
+ # set-up context
+ fixed_ctx = exc_details[1].__context__
+ raise exc_details[1]
+ except BaseException:
+ exc_details[1].__context__ = fixed_ctx
+ raise
+ return received_exc and suppressed_exc
+
+ def close(self):
+ """Immediately unwind the context stack."""
+ self.__exit__(None, None, None)
+
+
+# Inspired by discussions on https://bugs.python.org/issue29302
+class AsyncExitStack(_BaseExitStack, AbstractAsyncContextManager):
+ """Async context manager for dynamic management of a stack of exit
+ callbacks.
+
+ For example:
+ async with AsyncExitStack() as stack:
+ connections = [await stack.enter_async_context(get_connection())
+ for i in range(5)]
+ # All opened connections will automatically be released at the
+ # end of the async with statement, even if attempts to open a
+ # connection later in the list raise an exception.
+ """
+
+ @staticmethod
+ def _create_async_exit_wrapper(cm, cm_exit):
+ return MethodType(cm_exit, cm)
+
+ @staticmethod
+ def _create_async_cb_wrapper(callback, /, *args, **kwds):
+ async def _exit_wrapper(exc_type, exc, tb):
+ await callback(*args, **kwds)
+ return _exit_wrapper
+
+ async def enter_async_context(self, cm):
+ """Enters the supplied async context manager.
+
+ If successful, also pushes its __aexit__ method as a callback and
+ returns the result of the __aenter__ method.
+ """
+ cls = type(cm)
+ try:
+ _enter = cls.__aenter__
+ _exit = cls.__aexit__
+ except AttributeError:
+ raise TypeError(f"'{cls.__module__}.{cls.__qualname__}' object does "
+ f"not support the asynchronous context manager protocol"
+ ) from None
+ result = await _enter(cm)
+ self._push_async_cm_exit(cm, _exit)
+ return result
+
+ def push_async_exit(self, exit):
+ """Registers a coroutine function with the standard __aexit__ method
+ signature.
+
+ Can suppress exceptions the same way __aexit__ method can.
+ Also accepts any object with an __aexit__ method (registering a call
+ to the method instead of the object itself).
+ """
+ _cb_type = type(exit)
+ try:
+ exit_method = _cb_type.__aexit__
+ except AttributeError:
+ # Not an async context manager, so assume it's a coroutine function
+ self._push_exit_callback(exit, False)
+ else:
+ self._push_async_cm_exit(exit, exit_method)
+ return exit # Allow use as a decorator
+
+ def push_async_callback(self, callback, /, *args, **kwds):
+ """Registers an arbitrary coroutine function and arguments.
+
+ Cannot suppress exceptions.
+ """
+ _exit_wrapper = self._create_async_cb_wrapper(callback, *args, **kwds)
+
+ # We changed the signature, so using @wraps is not appropriate, but
+ # setting __wrapped__ may still help with introspection.
+ _exit_wrapper.__wrapped__ = callback
+ self._push_exit_callback(_exit_wrapper, False)
+ return callback # Allow use as a decorator
+
+ async def aclose(self):
+ """Immediately unwind the context stack."""
+ await self.__aexit__(None, None, None)
+
+ def _push_async_cm_exit(self, cm, cm_exit):
+ """Helper to correctly register coroutine function to __aexit__
+ method."""
+ _exit_wrapper = self._create_async_exit_wrapper(cm, cm_exit)
+ self._push_exit_callback(_exit_wrapper, False)
+
+ async def __aenter__(self):
+ return self
+
+ async def __aexit__(self, *exc_details):
+ received_exc = exc_details[0] is not None
+
+ # We manipulate the exception state so it behaves as though
+ # we were actually nesting multiple with statements
+ frame_exc = sys.exc_info()[1]
+ def _fix_exception_context(new_exc, old_exc):
+ # Context may not be correct, so find the end of the chain
+ while 1:
+ exc_context = new_exc.__context__
+ if exc_context is None or exc_context is old_exc:
+ # Context is already set correctly (see issue 20317)
+ return
+ if exc_context is frame_exc:
+ break
+ new_exc = exc_context
+ # Change the end of the chain to point to the exception
+ # we expect it to reference
+ new_exc.__context__ = old_exc
+
+ # Callbacks are invoked in LIFO order to match the behaviour of
+ # nested context managers
+ suppressed_exc = False
+ pending_raise = False
+ while self._exit_callbacks:
+ is_sync, cb = self._exit_callbacks.pop()
+ try:
+ if is_sync:
+ cb_suppress = cb(*exc_details)
+ else:
+ cb_suppress = await cb(*exc_details)
+
+ if cb_suppress:
+ suppressed_exc = True
+ pending_raise = False
+ exc_details = (None, None, None)
+ except:
+ new_exc_details = sys.exc_info()
+ # simulate the stack of exceptions by setting the context
+ _fix_exception_context(new_exc_details[1], exc_details[1])
+ pending_raise = True
+ exc_details = new_exc_details
+ if pending_raise:
+ try:
+ # bare "raise exc_details[1]" replaces our carefully
+ # set-up context
+ fixed_ctx = exc_details[1].__context__
+ raise exc_details[1]
+ except BaseException:
+ exc_details[1].__context__ = fixed_ctx
+ raise
+ return received_exc and suppressed_exc
+
+
+class nullcontext(AbstractContextManager, AbstractAsyncContextManager):
+ """Context manager that does no additional processing.
+
+ Used as a stand-in for a normal context manager, when a particular
+ block of code is only sometimes used with a normal context manager:
+
+ cm = optional_cm if condition else nullcontext()
+ with cm:
+ # Perform operation, using optional_cm if condition is True
+ """
+
+ def __init__(self, enter_result=None):
+ self.enter_result = enter_result
+
+ def __enter__(self):
+ return self.enter_result
+
+ def __exit__(self, *excinfo):
+ pass
+
+ async def __aenter__(self):
+ return self.enter_result
+
+ async def __aexit__(self, *excinfo):
+ pass
+
+
+class chdir(AbstractContextManager):
+ """Non thread-safe context manager to change the current working directory."""
+
+ def __init__(self, path):
+ self.path = path
+ self._old_cwd = []
+
+ def __enter__(self):
+ self._old_cwd.append(os.getcwd())
+ os.chdir(self.path)
+
+ def __exit__(self, *excinfo):
+ os.chdir(self._old_cwd.pop())