"""Event loop mixins."""
import threading
from . import events
_global_lock = threading.Lock()
# Used as a sentinel for loop parameter
_marker = object()
class _LoopBoundMixin:
_loop = None
def __init__(self, *, loop=_marker):
if loop is not _marker:
raise TypeError(
f'As of 3.10, the *loop* parameter was removed from '
f'{type(self).__name__}() since it is no longer necessary'
)
def _get_loop(self):
loop = events._get_running_loop()
if self._loop is None:
with _global_lock:
if self._loop is None:
self._loop = loop
if loop is not self._loop:
raise RuntimeError(f'{self!r} is bound to a different event loop')
return loop
