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concurrency.py
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concurrency.py
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import functools
import sys
import typing
import warnings
import anyio
if sys.version_info >= (3, 10): # pragma: no cover
from typing import ParamSpec
else: # pragma: no cover
from typing_extensions import ParamSpec
try:
import contextvars # Python 3.7+ only or via contextvars backport.
except ImportError: # pragma: no cover
contextvars = None # type: ignore
T = typing.TypeVar("T")
P = ParamSpec("P")
async def run_until_first_complete(*args: typing.Tuple[typing.Callable, dict]) -> None:
warnings.warn(
"run_until_first_complete is deprecated "
"and will be removed in a future version.",
DeprecationWarning,
)
async with anyio.create_task_group() as task_group:
async def run(func: typing.Callable[[], typing.Coroutine]) -> None:
await func()
task_group.cancel_scope.cancel()
for func, kwargs in args:
task_group.start_soon(run, functools.partial(func, **kwargs))
async def run_in_threadpool(
func: typing.Callable[P, T], *args: P.args, **kwargs: P.kwargs
) -> T:
if contextvars is not None: # pragma: no cover
# Ensure we run in the same context
child = functools.partial(func, *args, **kwargs)
context = contextvars.copy_context()
func = context.run # type: ignore[assignment]
args = (child,) # type: ignore[assignment]
elif kwargs: # pragma: no cover
# run_sync doesn't accept 'kwargs', so bind them in here
func = functools.partial(func, **kwargs)
return await anyio.to_thread.run_sync(func, *args)
class _StopIteration(Exception):
pass
def _next(iterator: typing.Iterator[T]) -> T:
# We can't raise `StopIteration` from within the threadpool iterator
# and catch it outside that context, so we coerce them into a different
# exception type.
try:
return next(iterator)
except StopIteration:
raise _StopIteration
async def iterate_in_threadpool(
iterator: typing.Iterator[T],
) -> typing.AsyncIterator[T]:
while True:
try:
yield await anyio.to_thread.run_sync(_next, iterator)
except _StopIteration:
break