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# This file is part of Pebble.
# Copyright (c) 2013-2025, Matteo Cafasso
# Pebble is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License
# as published by the Free Software Foundation,
# either version 3 of the License, or (at your option) any later version.
# Pebble is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Lesser General Public License for more details.
# You should have received a copy of the GNU Lesser General Public License
# along with Pebble. If not, see <http://www.gnu.org/licenses/>.
import signal
import threading
from functools import wraps
from typing import Any, Callable
_synchronized_lock = threading.Lock()
def synchronized(*args) -> Callable:
"""A synchronized function prevents two or more callers to interleave
its execution preventing race conditions.
The synchronized decorator accepts as optional parameter a Lock, RLock or
Semaphore object which will be employed to ensure the function's atomicity.
If no synchronization object is given, a single threading.Lock will be used.
This implies that between different decorated function only one at a time
will be executed.
"""
if callable(args[0]):
return decorate_synchronized(args[0], _synchronized_lock)
else:
def wrap(function) -> type:
return decorate_synchronized(function, args[0])
return wrap
def decorate_synchronized(function: Callable, lock: threading.Lock) -> Callable:
@wraps(function)
def wrapper(*args, **kwargs) -> Any:
with lock:
return function(*args, **kwargs)
return wrapper
def sighandler(signals: list) -> Callable:
"""Sets the decorated function as signal handler of given *signals*.
*signals* can be either a single signal or a list/tuple
of multiple ones.
"""
def wrap(function):
set_signal_handlers(signals, function)
@wraps(function)
def wrapper(*args, **kwargs):
return function(*args, **kwargs)
return wrapper
return wrap
def set_signal_handlers(signals: list, function: Callable):
if isinstance(signals, (list, tuple)):
for signum in signals:
signal.signal(signum, function)
else:
signal.signal(signals, function)
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