Coverage for python/lsst/daf/butler/_utilities/named_locks.py: 38%
18 statements
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« prev ^ index » next coverage.py v7.4.4, created at 2024-04-18 09:55 +0000
1# This file is part of daf_butler.
2#
3# Developed for the LSST Data Management System.
4# This product includes software developed by the LSST Project
5# (http://www.lsst.org).
6# See the COPYRIGHT file at the top-level directory of this distribution
7# for details of code ownership.
8#
9# This software is dual licensed under the GNU General Public License and also
10# under a 3-clause BSD license. Recipients may choose which of these licenses
11# to use; please see the files gpl-3.0.txt and/or bsd_license.txt,
12# respectively. If you choose the GPL option then the following text applies
13# (but note that there is still no warranty even if you opt for BSD instead):
14#
15# This program is free software: you can redistribute it and/or modify
16# it under the terms of the GNU General Public License as published by
17# the Free Software Foundation, either version 3 of the License, or
18# (at your option) any later version.
19#
20# This program is distributed in the hope that it will be useful,
21# but WITHOUT ANY WARRANTY; without even the implied warranty of
22# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
23# GNU General Public License for more details.
24#
25# You should have received a copy of the GNU General Public License
26# along with this program. If not, see <http://www.gnu.org/licenses/>.
28from collections.abc import Iterator
29from contextlib import contextmanager
30from threading import Lock
33class NamedLocks:
34 """Maintains a collection of separate mutex locks, indexed by name."""
36 def __init__(self) -> None:
37 self._lookup_lock = Lock()
38 self._named_locks = dict[str, Lock]()
40 @contextmanager
41 def lock(self, name: str) -> Iterator[None]:
42 """Return a context manager that acquires a mutex lock when entered and
43 releases it when exited.
45 Parameters
46 ----------
47 name : `str`
48 The name of the lock. A separate lock instance is created for each
49 distinct name.
50 """
51 with self._get_lock(name):
52 yield
54 def _get_lock(self, name: str) -> Lock:
55 with self._lookup_lock:
56 lock = self._named_locks.get(name, None)
57 if lock is None:
58 lock = Lock()
59 self._named_locks[name] = lock
61 return lock