"""
Implementation of the standard :mod:`thread` module that spawns greenlets.
.. note::
This module is a helper for :mod:`gevent.monkey` and is not
intended to be used directly. For spawning greenlets in your
applications, prefer higher level constructs like
:class:`gevent.Greenlet` class or :func:`gevent.spawn`.
"""
from __future__ import absolute_import
__implements__ = [
'allocate_lock',
'get_ident',
'exit',
'LockType',
'stack_size',
'start_new_thread',
'_local',
]
__imports__ = ['error']
import _thread as __thread__ # pylint:disable=import-error
__target__ = '_thread'
__imports__ += [
'TIMEOUT_MAX',
'allocate',
'exit_thread',
'interrupt_main',
'start_new'
]
# We can't actually produce a value that "may be used
# to identify this particular thread system-wide", right?
# Even if we could, I imagine people will want to pass this to
# non-Python (native) APIs, so we shouldn't mess with it.
__imports__.append('get_native_id')
# Added to 3.12
if hasattr(__thread__, 'daemon_threads_allowed'):
__imports__.append('daemon_threads_allowed')
error = __thread__.error
from gevent._compat import PYPY
from gevent._util import copy_globals
from gevent.hub import getcurrent
from gevent.hub import GreenletExit
from gevent.hub import sleep
from gevent._hub_local import get_hub_if_exists
from gevent.greenlet import Greenlet
from gevent.lock import BoundedSemaphore
from gevent.local import local as _local
from gevent.exceptions import LoopExit
if hasattr(__thread__, 'RLock'):
# Added in Python 3.4, backported to PyPy 2.7-7.0
__imports__.append("RLock")
def get_ident(gr=None):
if gr is None:
gr = getcurrent()
return id(gr)
def start_new_thread(function, args=(), kwargs=None):
if kwargs is not None:
greenlet = Greenlet.spawn(function, *args, **kwargs) # pylint:disable=not-a-mapping
else:
greenlet = Greenlet.spawn(function, *args)
return get_ident(greenlet)
[docs]
class LockType(BoundedSemaphore):
# Change the ValueError into the appropriate thread error
# and any other API changes we need to make to match behaviour
_OVER_RELEASE_ERROR = __thread__.error
if PYPY:
_OVER_RELEASE_ERROR = RuntimeError
_TIMEOUT_MAX = __thread__.TIMEOUT_MAX # pylint:disable=no-member
[docs]
def acquire(self, blocking=True, timeout=-1):
# This is the Python 3 signature.
# On Python 2, Lock.acquire has the signature `Lock.acquire([wait])`
# where `wait` is a boolean that cannot be passed by name, only position.
# so we're fine to use the Python 3 signature.
# Transform the default -1 argument into the None that our
# semaphore implementation expects, and raise the same error
# the stdlib implementation does.
if timeout == -1:
timeout = None
if not blocking and timeout is not None:
raise ValueError("can't specify a timeout for a non-blocking call")
if timeout is not None:
if timeout < 0:
# in C: if(timeout < 0 && timeout != -1)
raise ValueError("timeout value must be strictly positive")
if timeout > self._TIMEOUT_MAX:
raise OverflowError('timeout value is too large')
try:
acquired = BoundedSemaphore.acquire(self, blocking, timeout)
except LoopExit:
# Raised when the semaphore was not trivially ours, and we needed
# to block. Some other thread presumably owns the semaphore, and there are no greenlets
# running in this thread to switch to. So the best we can do is
# release the GIL and try again later.
if blocking: # pragma: no cover
raise
acquired = False
if not acquired and not blocking and getcurrent() is not get_hub_if_exists():
# Run other callbacks. This makes spin locks works.
# We can't do this if we're in the hub, which we could easily be:
# printing the repr of a thread checks its tstate_lock, and sometimes we
# print reprs in the hub.
# See https://github.com/gevent/gevent/issues/1464
# By using sleep() instead of self.wait(0), we don't force a trip
# around the event loop *unless* we've been running callbacks for
# longer than our switch interval.
sleep()
return acquired
# Should we implement _is_owned, at least for Python 2? See notes in
# monkey.py's patch_existing_locks.
allocate_lock = LockType
def exit():
raise GreenletExit
if hasattr(__thread__, 'stack_size'):
_original_stack_size = __thread__.stack_size
def stack_size(size=None):
if size is None:
return _original_stack_size()
if size > _original_stack_size():
return _original_stack_size(size)
# not going to decrease stack_size, because otherwise other
# greenlets in this thread will suffer
else:
__implements__.remove('stack_size')
__imports__ = copy_globals(__thread__, globals(),
only_names=__imports__,
ignore_missing_names=True)
__all__ = __implements__ + __imports__
__all__.remove('_local')
# XXX interrupt_main
# XXX _count()