395 lines
12 KiB
Python
395 lines
12 KiB
Python
|
#
|
||
|
|
# Module implementing synchronization primitives
|
||
|
|
#
|
||
|
|
# multiprocessing/synchronize.py
|
||
|
|
#
|
||
|
|
# Copyright (c) 2006-2008, R Oudkerk
|
||
|
|
# Licensed to PSF under a Contributor Agreement.
|
||
|
|
#
|
||
|
|
|
||
|
|
__all__ = [
|
||
|
|
'Lock', 'RLock', 'Semaphore', 'BoundedSemaphore', 'Condition', 'Event'
|
||
|
|
]
|
||
|
|
|
||
|
|
import threading
|
||
|
|
import sys
|
||
|
|
import tempfile
|
||
|
|
import _multiprocessing
|
||
|
|
import time
|
||
|
|
|
||
|
|
from . import context
|
||
|
|
from . import process
|
||
|
|
from . import util
|
||
|
|
|
||
|
|
# 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:
|
||
|
|
from _multiprocessing import SemLock, 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.")
|
||
|
|
|
||
|
|
#
|
||
|
|
# 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, *, ctx):
|
||
|
|
if ctx is None:
|
||
|
|
ctx = context._default_context.get_context()
|
||
|
|
name = ctx.get_start_method()
|
||
|
|
unlink_now = sys.platform == 'win32' or name == 'fork'
|
||
|
|
for i in range(100):
|
||
|
|
try:
|
||
|
|
sl = self._semlock = _multiprocessing.SemLock(
|
||
|
|
kind, value, maxvalue, self._make_name(),
|
||
|
|
unlink_now)
|
||
|
|
except FileExistsError:
|
||
|
|
pass
|
||
|
|
else:
|
||
|
|
break
|
||
|
|
else:
|
||
|
|
raise FileExistsError('cannot find name for semaphore')
|
||
|
|
|
||
|
|
util.debug('created semlock with handle %s' % sl.handle)
|
||
|
|
self._make_methods()
|
||
|
|
|
||
|
|
if sys.platform != 'win32':
|
||
|
|
def _after_fork(obj):
|
||
|
|
obj._semlock._after_fork()
|
||
|
|
util.register_after_fork(self, _after_fork)
|
||
|
|
|
||
|
|
if self._semlock.name is not None:
|
||
|
|
# We only get here if we are on Unix with forking
|
||
|
|
# disabled. When the object is garbage collected or the
|
||
|
|
# process shuts down we unlink the semaphore name
|
||
|
|
from .semaphore_tracker import register
|
||
|
|
register(self._semlock.name)
|
||
|
|
util.Finalize(self, SemLock._cleanup, (self._semlock.name,),
|
||
|
|
exitpriority=0)
|
||
|
|
|
||
|
|
@staticmethod
|
||
|
|
def _cleanup(name):
|
||
|
|
from .semaphore_tracker import unregister
|
||
|
|
sem_unlink(name)
|
||
|
|
unregister(name)
|
||
|
|
|
||
|
|
def _make_methods(self):
|
||
|
|
self.acquire = self._semlock.acquire
|
||
|
|
self.release = self._semlock.release
|
||
|
|
|
||
|
|
def __enter__(self):
|
||
|
|
return self._semlock.__enter__()
|
||
|
|
|
||
|
|
def __exit__(self, *args):
|
||
|
|
return self._semlock.__exit__(*args)
|
||
|
|
|
||
|
|
def __getstate__(self):
|
||
|
|
context.assert_spawning(self)
|
||
|
|
sl = self._semlock
|
||
|
|
if sys.platform == 'win32':
|
||
|
|
h = context.get_spawning_popen().duplicate_for_child(sl.handle)
|
||
|
|
else:
|
||
|
|
h = sl.handle
|
||
|
|
return (h, sl.kind, sl.maxvalue, sl.name)
|
||
|
|
|
||
|
|
def __setstate__(self, state):
|
||
|
|
self._semlock = _multiprocessing.SemLock._rebuild(*state)
|
||
|
|
util.debug('recreated blocker with handle %r' % state[0])
|
||
|
|
self._make_methods()
|
||
|
|
|
||
|
|
@staticmethod
|
||
|
|
def _make_name():
|
||
|
|
return '%s-%s' % (process.current_process()._config['semprefix'],
|
||
|
|
next(SemLock._rand))
|
||
|
|
|
||
|
|
#
|
||
|
|
# Semaphore
|
||
|
|
#
|
||
|
|
|
||
|
|
class Semaphore(SemLock):
|
||
|
|
|
||
|
|
def __init__(self, value=1, *, ctx):
|
||
|
|
SemLock.__init__(self, SEMAPHORE, value, SEM_VALUE_MAX, ctx=ctx)
|
||
|
|
|
||
|
|
def get_value(self):
|
||
|
|
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, *, ctx):
|
||
|
|
SemLock.__init__(self, SEMAPHORE, value, value, ctx=ctx)
|
||
|
|
|
||
|
|
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, *, ctx):
|
||
|
|
SemLock.__init__(self, SEMAPHORE, 1, 1, ctx=ctx)
|
||
|
|
|
||
|
|
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, *, ctx):
|
||
|
|
SemLock.__init__(self, RECURSIVE_MUTEX, 1, 1, ctx=ctx)
|
||
|
|
|
||
|
|
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, *, ctx):
|
||
|
|
self._lock = lock or ctx.RLock()
|
||
|
|
self._sleeping_count = ctx.Semaphore(0)
|
||
|
|
self._woken_count = ctx.Semaphore(0)
|
||
|
|
self._wait_semaphore = ctx.Semaphore(0)
|
||
|
|
self._make_methods()
|
||
|
|
|
||
|
|
def __getstate__(self):
|
||
|
|
context.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, n=1):
|
||
|
|
assert self._lock._semlock._is_mine(), 'lock is not owned'
|
||
|
|
assert not self._wait_semaphore.acquire(
|
||
|
|
False), ('notify: Should not have been able to acquire'
|
||
|
|
+ '_wait_semaphore')
|
||
|
|
|
||
|
|
# 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, ('notify: Bug in sleeping_count.acquire'
|
||
|
|
+ '- res should not be False')
|
||
|
|
|
||
|
|
sleepers = 0
|
||
|
|
while sleepers < n and 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 notify_all(self):
|
||
|
|
self.notify(n=sys.maxsize)
|
||
|
|
|
||
|
|
def wait_for(self, predicate, timeout=None):
|
||
|
|
result = predicate()
|
||
|
|
if result:
|
||
|
|
return result
|
||
|
|
if timeout is not None:
|
||
|
|
endtime = time.monotonic() + timeout
|
||
|
|
else:
|
||
|
|
endtime = None
|
||
|
|
waittime = None
|
||
|
|
while not result:
|
||
|
|
if endtime is not None:
|
||
|
|
waittime = endtime - time.monotonic()
|
||
|
|
if waittime <= 0:
|
||
|
|
break
|
||
|
|
self.wait(waittime)
|
||
|
|
result = predicate()
|
||
|
|
return result
|
||
|
|
|
||
|
|
#
|
||
|
|
# Event
|
||
|
|
#
|
||
|
|
|
||
|
|
class Event(object):
|
||
|
|
|
||
|
|
def __init__(self, *, ctx):
|
||
|
|
self._cond = ctx.Condition(ctx.Lock())
|
||
|
|
self._flag = ctx.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
|
||
|
|
|
||
|
|
#
|
||
|
|
# Barrier
|
||
|
|
#
|
||
|
|
|
||
|
|
class Barrier(threading.Barrier):
|
||
|
|
|
||
|
|
def __init__(self, parties, action=None, timeout=None, *, ctx):
|
||
|
|
import struct
|
||
|
|
from .heap import BufferWrapper
|
||
|
|
wrapper = BufferWrapper(struct.calcsize('i') * 2)
|
||
|
|
cond = ctx.Condition()
|
||
|
|
self.__setstate__((parties, action, timeout, cond, wrapper))
|
||
|
|
self._state = 0
|
||
|
|
self._count = 0
|
||
|
|
|
||
|
|
def __setstate__(self, state):
|
||
|
|
(self._parties, self._action, self._timeout,
|
||
|
|
self._cond, self._wrapper) = state
|
||
|
|
self._array = self._wrapper.create_memoryview().cast('i')
|
||
|
|
|
||
|
|
def __getstate__(self):
|
||
|
|
return (self._parties, self._action, self._timeout,
|
||
|
|
self._cond, self._wrapper)
|
||
|
|
|
||
|
|
@property
|
||
|
|
def _state(self):
|
||
|
|
return self._array[0]
|
||
|
|
|
||
|
|
@_state.setter
|
||
|
|
def _state(self, value):
|
||
|
|
self._array[0] = value
|
||
|
|
|
||
|
|
@property
|
||
|
|
def _count(self):
|
||
|
|
return self._array[1]
|
||
|
|
|
||
|
|
@_count.setter
|
||
|
|
def _count(self, value):
|
||
|
|
self._array[1] = value
|