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v0.5.1
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Revision e41bfd15dd148627b4f39c2a5837bddd8894d345 authored by Terry Jan Reedy on 30 November 2020, 17:09:43 UTC, committed by GitHub on 30 November 2020, 17:09:43 UTC
restart_subprocess is a method of self, the pyshell.InteractiveInterpreter instance. The latter does not have an interp attribute redundantly referring to itself. (The PyShell instance does have an interp attribute, referring to the InteractiveInterpreter instance.)
1 parent 0be9ce3
Tip revision: e41bfd15dd148627b4f39c2a5837bddd8894d345 authored by Terry Jan Reedy on 30 November 2020, 17:09:43 UTC
bpo-42508: Remove bogus idlelib.pyshell.ModifiedInterpreter attribute (GH-23570)
bpo-42508: Remove bogus idlelib.pyshell.ModifiedInterpreter attribute (GH-23570)
Tip revision: e41bfd1
synchronize.py
#
# 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 .resource_tracker import register
register(self._semlock.name, "semaphore")
util.Finalize(self, SemLock._cleanup, (self._semlock.name,),
exitpriority=0)
@staticmethod
def _cleanup(name):
from .resource_tracker import unregister
sem_unlink(name)
unregister(name, "semaphore")
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
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