"""
Implementation of the standard :mod:`threading` using 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__ = [
'local',
'_start_new_thread',
'_allocate_lock',
'Lock',
'_get_ident',
'_sleep',
'_DummyThread',
]
import threading as __threading__
_DummyThread_ = __threading__._DummyThread
from gevent.local import local
from gevent.thread import start_new_thread as _start_new_thread, allocate_lock as _allocate_lock, get_ident as _get_ident
from gevent._compat import PYPY
from gevent.hub import sleep as _sleep, getcurrent
# Exports, prevent unused import warnings
local = local
start_new_thread = _start_new_thread
allocate_lock = _allocate_lock
_get_ident = _get_ident
_sleep = _sleep
getcurrent = getcurrent
Lock = _allocate_lock
def _cleanup(g):
__threading__._active.pop(id(g), None)
def _make_cleanup_id(gid):
def _(_r):
__threading__._active.pop(gid, None)
return _
_weakref = None
class _DummyThread(_DummyThread_):
# We avoid calling the superclass constructor. This makes us about
# twice as fast (1.16 vs 0.68usec on PyPy, 29.3 vs 17.7usec on
# CPython 2.7), and has the important effect of avoiding
# allocation and then immediate deletion of _Thread__block, a
# lock. This is especially important on PyPy where locks go
# through the cpyext API and Cython, which is known to be slow and
# potentially buggy (e.g.,
# https://bitbucket.org/pypy/pypy/issues/2149/memory-leak-for-python-subclass-of-cpyext#comment-22347393)
# These objects are constructed quite frequently in some cases, so
# the optimization matters: for example, in gunicorn, which uses
# pywsgi.WSGIServer, every request is handled in a new greenlet,
# and every request uses a logging.Logger to write the access log,
# and every call to a log method captures the current thread (by
# default).
#
# (Obviously we have to duplicate the effects of the constructor,
# at least for external state purposes, which is potentially
# slightly fragile.)
# For the same reason, instances of this class will cleanup their own entry
# in ``threading._active``
# Capture the static things as class vars to save on memory/
# construction time.
# In Py2, they're all private; in Py3, they become protected
_Thread__stopped = _is_stopped = _stopped = False
_Thread__initialized = _initialized = True
_Thread__daemonic = _daemonic = True
_Thread__args = _args = ()
_Thread__kwargs = _kwargs = None
_Thread__target = _target = None
_Thread_ident = _ident = None
_Thread__started = _started = __threading__.Event()
_Thread__started.set()
_tstate_lock = None
def __init__(self):
#_DummyThread_.__init__(self) # pylint:disable=super-init-not-called
# It'd be nice to use a pattern like "greenlet-%d", but maybe somebody out
# there is checking thread names...
self._name = self._Thread__name = __threading__._newname("DummyThread-%d")
self._set_ident()
g = getcurrent()
gid = _get_ident(g) # same as id(g)
__threading__._active[gid] = self
rawlink = getattr(g, 'rawlink', None)
if rawlink is not None:
# raw greenlet.greenlet greenlets don't
# have rawlink...
rawlink(_cleanup)
else:
# ... so for them we use weakrefs.
# See https://github.com/gevent/gevent/issues/918
global _weakref
if _weakref is None:
_weakref = __import__('weakref')
ref = _weakref.ref(g, _make_cleanup_id(gid))
self.__raw_ref = ref
def _Thread__stop(self):
pass
_stop = _Thread__stop # py3
def _wait_for_tstate_lock(self, *args, **kwargs):
# pylint:disable=arguments-differ
pass
if hasattr(__threading__, 'main_thread'): # py 3.4+
def main_native_thread():
return __threading__.main_thread() # pylint:disable=no-member
else:
_main_threads = [(_k, _v) for _k, _v in __threading__._active.items()
if isinstance(_v, __threading__._MainThread)]
assert len(_main_threads) == 1, "Too many main threads"
def main_native_thread():
return _main_threads[0][1]
# Make sure the MainThread can be found by our current greenlet ID,
# otherwise we get a new DummyThread, which cannot be joined.
# Fixes tests in test_threading_2 under PyPy, and generally makes things nicer
# when gevent.threading is imported before monkey patching or not at all
# XXX: This assumes that the import is happening in the "main" greenlet/thread.
# XXX: We should really only be doing this from gevent.monkey.
if _get_ident() not in __threading__._active:
_v = main_native_thread()
_k = _v.ident
del __threading__._active[_k]
_v._ident = _v._Thread__ident = _get_ident()
__threading__._active[_get_ident()] = _v
del _k
del _v
# Avoid printing an error on shutdown trying to remove the thread entry
# we just replaced if we're not fully monkey patched in
# XXX: This causes a hang on PyPy for some unknown reason (as soon as class _active
# defines __delitem__, shutdown hangs. Maybe due to something with the GC?
# XXX: This may be fixed in 2.6.1+
if not PYPY:
# pylint:disable=no-member
_MAIN_THREAD = __threading__._get_ident() if hasattr(__threading__, '_get_ident') else __threading__.get_ident()
class _active(dict):
def __delitem__(self, k):
if k == _MAIN_THREAD and k not in self:
return
dict.__delitem__(self, k)
__threading__._active = _active(__threading__._active)
import sys
if sys.version_info[:2] >= (3, 4):
# XXX: Issue 18808 breaks us on Python 3.4.
# Thread objects now expect a callback from the interpreter itself
# (threadmodule.c:release_sentinel). Because this never happens
# when a greenlet exits, join() and friends will block forever.
# The solution below involves capturing the greenlet when it is
# started and deferring the known broken methods to it.
class Thread(__threading__.Thread):
_greenlet = None
def is_alive(self):
return bool(self._greenlet)
isAlive = is_alive
def _set_tstate_lock(self):
self._greenlet = getcurrent()
def run(self):
try:
super(Thread, self).run()
finally:
# avoid ref cycles, but keep in __dict__ so we can
# distinguish the started/never-started case
self._greenlet = None
self._stop() # mark as finished
def join(self, timeout=None):
if '_greenlet' not in self.__dict__:
raise RuntimeError("Cannot join an inactive thread")
if self._greenlet is None:
return
self._greenlet.join(timeout=timeout)
def _wait_for_tstate_lock(self, *args, **kwargs):
# pylint:disable=arguments-differ
raise NotImplementedError()
__implements__.append('Thread')
# The main thread is patched up with more care in monkey.py
#t = __threading__.current_thread()
#if isinstance(t, __threading__.Thread):
# t.__class__ = Thread
# t._greenlet = getcurrent()
if sys.version_info[:2] >= (3, 3):
__implements__.remove('_get_ident')
__implements__.append('get_ident')
get_ident = _get_ident
__implements__.remove('_sleep')
# Python 3 changed the implementation of threading.RLock
# Previously it was a factory function around threading._RLock
# which in turn used _allocate_lock. Now, it wants to use
# threading._CRLock, which is imported from _thread.RLock and as such
# is implemented in C. So it bypasses our _allocate_lock function.
# Fortunately they left the Python fallback in place
assert hasattr(__threading__, '_CRLock'), "Unsupported Python version"
_CRLock = None
__implements__.append('_CRLock')