# Copyright (c) 2026, NVIDIA CORPORATION. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import threading
[docs]
class CallbackAdmission:
"""Close callback admission and wait until every admitted callback returns."""
def __init__(self):
self._condition = threading.Condition()
self._closed = False
self._active = 0
[docs]
def enter(self) -> bool:
with self._condition:
if self._closed:
return False
self._active += 1
return True
[docs]
def leave(self) -> None:
with self._condition:
if self._active <= 0:
raise RuntimeError("callback admission leave without matching enter")
self._active -= 1
if self._active == 0:
self._condition.notify_all()
[docs]
def close(self) -> None:
with self._condition:
self._closed = True
[docs]
def wait(self, timeout: float) -> bool:
"""Wait up to ``timeout`` seconds for admitted callbacks to return."""
if timeout < 0:
raise ValueError("timeout must not be negative")
with self._condition:
return self._condition.wait_for(lambda: self._active == 0, timeout=timeout)