# util/_compat_py3k.py
# Copyright (C) 2005-2024 the SQLAlchemy authors and contributors
# <see AUTHORS file>
#
# This module is part of SQLAlchemy and is released under
# the MIT License: https://www.opensource.org/licenses/mit-license.php
from functools import wraps
# vendored from py3.7
class _AsyncGeneratorContextManager:
"""Helper for @asynccontextmanager."""
def __init__(self, func, args, kwds):
self.gen = func(*args, **kwds)
self.func, self.args, self.kwds = func, args, kwds
doc = getattr(func, "__doc__", None)
if doc is None:
doc = type(self).__doc__
self.__doc__ = doc
async def __aenter__(self):
try:
return await self.gen.__anext__()
except StopAsyncIteration:
raise RuntimeError("generator didn't yield") from None
async def __aexit__(self, typ, value, traceback):
if typ is None:
try:
await self.gen.__anext__()
except StopAsyncIteration:
return
else:
raise RuntimeError("generator didn't stop")
else:
if value is None:
value = typ()
# See _GeneratorContextManager.__exit__ for comments on subtleties
# in this implementation
try:
await self.gen.athrow(typ, value, traceback)
raise RuntimeError("generator didn't stop after athrow()")
except StopAsyncIteration as exc:
return exc is not value
except RuntimeError as exc:
if exc is value:
return False
if isinstance(value, (StopIteration, StopAsyncIteration)):
if exc.__cause__ is value:
return False
raise
except BaseException as exc:
if exc is not value:
raise
# using the vendored version in all cases at the moment to establish
# full test coverage
def asynccontextmanager(func):
@wraps(func)
def helper(*args, **kwds):
return _AsyncGeneratorContextManager(func, args, kwds)
return helper
