projektAI/venv/Lib/site-packages/joblib/externals/loky/backend/synchronize.py

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2021-06-06 22:13:05 +02:00
###############################################################################
# Synchronization primitives based on our SemLock implementation
#
# author: Thomas Moreau and Olivier Grisel
#
# adapted from multiprocessing/synchronize.py (17/02/2017)
# * Remove ctx argument for compatibility reason
# * Implementation of Condition/Event are necessary for compatibility
# with python2.7/3.3, Barrier should be reimplemented to for those
# version (but it is not used in loky).
#
import os
import sys
import tempfile
import threading
import _multiprocessing
from time import time as _time
from .context import assert_spawning
from . import resource_tracker
from multiprocessing import process
from multiprocessing import util
__all__ = [
'Lock', 'RLock', 'Semaphore', 'BoundedSemaphore', 'Condition', 'Event'
]
# Try to import the mp.synchronize module cleanly, if it fails
# raise ImportError for platforms lacking a working sem_open implementation.
# See issue 3770
try:
if sys.version_info < (3, 4):
from .semlock import SemLock as _SemLock
from .semlock import sem_unlink
else:
from _multiprocessing import SemLock as _SemLock
from _multiprocessing import sem_unlink
except (ImportError):
raise ImportError("This platform lacks a functioning sem_open" +
" implementation, therefore, the required" +
" synchronization primitives needed will not" +
" function, see issue 3770.")
if sys.version_info[:2] < (3, 3):
FileExistsError = OSError
#
# Constants
#
RECURSIVE_MUTEX, SEMAPHORE = list(range(2))
SEM_VALUE_MAX = _multiprocessing.SemLock.SEM_VALUE_MAX
#
# Base class for semaphores and mutexes; wraps `_multiprocessing.SemLock`
#
class SemLock(object):
_rand = tempfile._RandomNameSequence()
def __init__(self, kind, value, maxvalue):
# unlink_now is only used on win32 or when we are using fork.
unlink_now = False
for i in range(100):
try:
self._semlock = _SemLock(
kind, value, maxvalue, SemLock._make_name(),
unlink_now)
except FileExistsError: # pragma: no cover
pass
else:
break
else: # pragma: no cover
raise FileExistsError('cannot find name for semaphore')
util.debug('created semlock with handle %s and name "%s"'
% (self._semlock.handle, self._semlock.name))
self._make_methods()
def _after_fork(obj):
obj._semlock._after_fork()
util.register_after_fork(self, _after_fork)
# When the object is garbage collected or the
# process shuts down we unlink the semaphore name
resource_tracker.register(self._semlock.name, "semlock")
util.Finalize(self, SemLock._cleanup, (self._semlock.name,),
exitpriority=0)
@staticmethod
def _cleanup(name):
sem_unlink(name)
resource_tracker.unregister(name, "semlock")
def _make_methods(self):
self.acquire = self._semlock.acquire
self.release = self._semlock.release
def __enter__(self):
return self._semlock.acquire()
def __exit__(self, *args):
return self._semlock.release()
def __getstate__(self):
assert_spawning(self)
sl = self._semlock
h = sl.handle
return (h, sl.kind, sl.maxvalue, sl.name)
def __setstate__(self, state):
self._semlock = _SemLock._rebuild(*state)
util.debug('recreated blocker with handle %r and name "%s"'
% (state[0], state[3]))
self._make_methods()
@staticmethod
def _make_name():
# OSX does not support long names for semaphores
return '/loky-%i-%s' % (os.getpid(), next(SemLock._rand))
#
# Semaphore
#
class Semaphore(SemLock):
def __init__(self, value=1):
SemLock.__init__(self, SEMAPHORE, value, SEM_VALUE_MAX)
def get_value(self):
if sys.platform == 'darwin':
raise NotImplementedError("OSX does not implement sem_getvalue")
return self._semlock._get_value()
def __repr__(self):
try:
value = self._semlock._get_value()
except Exception:
value = 'unknown'
return '<%s(value=%s)>' % (self.__class__.__name__, value)
#
# Bounded semaphore
#
class BoundedSemaphore(Semaphore):
def __init__(self, value=1):
SemLock.__init__(self, SEMAPHORE, value, value)
def __repr__(self):
try:
value = self._semlock._get_value()
except Exception:
value = 'unknown'
return '<%s(value=%s, maxvalue=%s)>' % \
(self.__class__.__name__, value, self._semlock.maxvalue)
#
# Non-recursive lock
#
class Lock(SemLock):
def __init__(self):
super(Lock, self).__init__(SEMAPHORE, 1, 1)
def __repr__(self):
try:
if self._semlock._is_mine():
name = process.current_process().name
if threading.current_thread().name != 'MainThread':
name += '|' + threading.current_thread().name
elif self._semlock._get_value() == 1:
name = 'None'
elif self._semlock._count() > 0:
name = 'SomeOtherThread'
else:
name = 'SomeOtherProcess'
except Exception:
name = 'unknown'
return '<%s(owner=%s)>' % (self.__class__.__name__, name)
#
# Recursive lock
#
class RLock(SemLock):
def __init__(self):
super(RLock, self).__init__(RECURSIVE_MUTEX, 1, 1)
def __repr__(self):
try:
if self._semlock._is_mine():
name = process.current_process().name
if threading.current_thread().name != 'MainThread':
name += '|' + threading.current_thread().name
count = self._semlock._count()
elif self._semlock._get_value() == 1:
name, count = 'None', 0
elif self._semlock._count() > 0:
name, count = 'SomeOtherThread', 'nonzero'
else:
name, count = 'SomeOtherProcess', 'nonzero'
except Exception:
name, count = 'unknown', 'unknown'
return '<%s(%s, %s)>' % (self.__class__.__name__, name, count)
#
# Condition variable
#
class Condition(object):
def __init__(self, lock=None):
self._lock = lock or RLock()
self._sleeping_count = Semaphore(0)
self._woken_count = Semaphore(0)
self._wait_semaphore = Semaphore(0)
self._make_methods()
def __getstate__(self):
assert_spawning(self)
return (self._lock, self._sleeping_count,
self._woken_count, self._wait_semaphore)
def __setstate__(self, state):
(self._lock, self._sleeping_count,
self._woken_count, self._wait_semaphore) = state
self._make_methods()
def __enter__(self):
return self._lock.__enter__()
def __exit__(self, *args):
return self._lock.__exit__(*args)
def _make_methods(self):
self.acquire = self._lock.acquire
self.release = self._lock.release
def __repr__(self):
try:
num_waiters = (self._sleeping_count._semlock._get_value() -
self._woken_count._semlock._get_value())
except Exception:
num_waiters = 'unknown'
return '<%s(%s, %s)>' % (self.__class__.__name__,
self._lock, num_waiters)
def wait(self, timeout=None):
assert self._lock._semlock._is_mine(), \
'must acquire() condition before using wait()'
# indicate that this thread is going to sleep
self._sleeping_count.release()
# release lock
count = self._lock._semlock._count()
for i in range(count):
self._lock.release()
try:
# wait for notification or timeout
return self._wait_semaphore.acquire(True, timeout)
finally:
# indicate that this thread has woken
self._woken_count.release()
# reacquire lock
for i in range(count):
self._lock.acquire()
def notify(self):
assert self._lock._semlock._is_mine(), 'lock is not owned'
assert not self._wait_semaphore.acquire(False)
# to take account of timeouts since last notify() we subtract
# woken_count from sleeping_count and rezero woken_count
while self._woken_count.acquire(False):
res = self._sleeping_count.acquire(False)
assert res
if self._sleeping_count.acquire(False): # try grabbing a sleeper
self._wait_semaphore.release() # wake up one sleeper
self._woken_count.acquire() # wait for the sleeper to wake
# rezero _wait_semaphore in case a timeout just happened
self._wait_semaphore.acquire(False)
def notify_all(self):
assert self._lock._semlock._is_mine(), 'lock is not owned'
assert not self._wait_semaphore.acquire(False)
# to take account of timeouts since last notify*() we subtract
# woken_count from sleeping_count and rezero woken_count
while self._woken_count.acquire(False):
res = self._sleeping_count.acquire(False)
assert res
sleepers = 0
while self._sleeping_count.acquire(False):
self._wait_semaphore.release() # wake up one sleeper
sleepers += 1
if sleepers:
for i in range(sleepers):
self._woken_count.acquire() # wait for a sleeper to wake
# rezero wait_semaphore in case some timeouts just happened
while self._wait_semaphore.acquire(False):
pass
def wait_for(self, predicate, timeout=None):
result = predicate()
if result:
return result
if timeout is not None:
endtime = _time() + timeout
else:
endtime = None
waittime = None
while not result:
if endtime is not None:
waittime = endtime - _time()
if waittime <= 0:
break
self.wait(waittime)
result = predicate()
return result
#
# Event
#
class Event(object):
def __init__(self):
self._cond = Condition(Lock())
self._flag = Semaphore(0)
def is_set(self):
with self._cond:
if self._flag.acquire(False):
self._flag.release()
return True
return False
def set(self):
with self._cond:
self._flag.acquire(False)
self._flag.release()
self._cond.notify_all()
def clear(self):
with self._cond:
self._flag.acquire(False)
def wait(self, timeout=None):
with self._cond:
if self._flag.acquire(False):
self._flag.release()
else:
self._cond.wait(timeout)
if self._flag.acquire(False):
self._flag.release()
return True
return False