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# -*- coding: utf-8 -*-
#
# This file is part of Linux Show Player
#
# Copyright 2012-2016 Francesco Ceruti <ceppofrancy@gmail.com>
#
# Linux Show Player is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Linux Show Player 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Linux Show Player. If not, see <http://www.gnu.org/licenses/>.
import logging
import traceback
from functools import wraps, partial
from threading import Thread, Lock, RLock
def async_function(target):
"""Decorator. Make a function asynchronous.
The decorated function is executed in a differed thread.
"""
@wraps(target)
def wrapped(*args, **kwargs):
Thread(target=target, args=args, kwargs=kwargs, daemon=True).start()
return wrapped
def async_in_pool(pool):
"""Decorator. Make a function asynchronous in a specified pool.
The decorated function is executed in the specified threads-pool.
.. Usage::
class MyClass:
__MyPool = ThreadPoolExecutor(10)
@async_in_pool(__MyPool)
def do_some_task(self):
pass
"""
def decorator(target):
@wraps(target)
def wrapped(*args, **kwargs):
pool.submit(target, *args, **kwargs)
return wrapped
return decorator
def locked_function(target=None, *, lock=None, blocking=True, timeout=-1):
"""Decorator. Make a *function* "synchronized".
Only one thread at time can access the decorated function.
:param target: the function to decorate
:param lock: the lock to be used (if not specified an RLock is created)
:param blocking: if True the lock-acquirement is blocking
:param timeout: timeout for the lock-acquirement
"""
# If called with (keywords) arguments
if target is None:
return partial(locked_function, lock=lock, blocking=blocking,
timeout=timeout)
if lock is None:
target.__lock__ = RLock()
else:
target.__lock__ = lock
@wraps(target)
def locked(*args, **kwargs):
try:
if target.__lock__.acquire(blocking=blocking, timeout=timeout):
return target(*args, **kwargs)
else:
return
finally:
try:
target.__lock__.release()
except RuntimeError:
pass
return locked
def locked_method(target=None, *, blocking=True, timeout=-1):
"""Decorator. Make a *method* synchronized.
Only one thread at time can access the decorated method.
:param target: the function to decorate
:param blocking: if True the lock-acquirement is blocking
:param timeout: timeout for the lock-acquirement
"""
# If called with (keywords) arguments
if target is None:
return partial(locked_method, blocking=blocking, timeout=timeout)
# generate a lock_name like "__method_name_lock__"
lock_name = '__' + target.__name__ + '_lock__'
target.__meta_lock__ = Lock()
@wraps(target)
def locked(self, *args, **kwargs):
with target.__meta_lock__:
lock = getattr(self, lock_name, None)
# If the lock is not defined, then define it
if lock is None:
lock = RLock()
setattr(self, lock_name, lock)
try:
if lock.acquire(blocking=blocking, timeout=timeout):
return target(self, *args, **kwargs)
else:
return
finally:
try:
lock.release()
except RuntimeError:
pass
return locked
def suppress_exceptions(target=None, *, log=True):
"""Decorator. Suppress all the exception in the decorated function.
:param log: If True (the default) exceptions are logged as warnings.
"""
if target is None:
return partial(suppress_exceptions, print_exc=log)
@wraps(target)
def wrapped(*args, **kwargs):
try:
return target(*args, **kwargs)
except Exception:
logging.warning('Exception suppressed:\n' + traceback.format_exc())
return wrapped
def memoize(callable_):
"""Decorator. Caches a function's return value each time it is called.
If called later with the same arguments, the cached value is returned
(not reevaluated).
.. Note::
This works for any callable object.
The arguments are cached (as strings) in object.cache.
"""
cache = callable_.cache = {}
@wraps(callable_)
def memoizer(*args, **kwargs):
key = str(args) + str(kwargs)
if key not in cache:
cache[key] = callable_(*args, **kwargs)
return cache[key]
return memoizer
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