691 lines
27 KiB
Python
691 lines
27 KiB
Python
"""
|
|
libuv loop implementation
|
|
"""
|
|
# pylint: disable=no-member
|
|
from __future__ import absolute_import, print_function
|
|
|
|
import os
|
|
from collections import defaultdict
|
|
from collections import namedtuple
|
|
from operator import delitem
|
|
import signal
|
|
|
|
from zope.interface import implementer
|
|
|
|
from gevent import getcurrent
|
|
from gevent.exceptions import LoopExit
|
|
|
|
from gevent._ffi import _dbg # pylint: disable=unused-import
|
|
from gevent._ffi.loop import AbstractLoop
|
|
from gevent._ffi.loop import assign_standard_callbacks
|
|
from gevent._ffi.loop import AbstractCallbacks
|
|
from gevent._interfaces import ILoop
|
|
from gevent.libuv import _corecffi # pylint:disable=no-name-in-module,import-error
|
|
|
|
ffi = _corecffi.ffi
|
|
libuv = _corecffi.lib
|
|
|
|
__all__ = [
|
|
]
|
|
|
|
|
|
class _Callbacks(AbstractCallbacks):
|
|
|
|
def _find_loop_from_c_watcher(self, watcher_ptr):
|
|
loop_handle = ffi.cast('uv_handle_t*', watcher_ptr).data
|
|
return self.from_handle(loop_handle) if loop_handle else None
|
|
|
|
def python_sigchld_callback(self, watcher_ptr, _signum):
|
|
self.from_handle(ffi.cast('uv_handle_t*', watcher_ptr).data)._sigchld_callback()
|
|
|
|
def python_timer0_callback(self, watcher_ptr):
|
|
return self.python_prepare_callback(watcher_ptr)
|
|
|
|
def python_queue_callback(self, watcher_ptr, revents):
|
|
watcher_handle = watcher_ptr.data
|
|
the_watcher = self.from_handle(watcher_handle)
|
|
|
|
the_watcher.loop._queue_callback(watcher_ptr, revents)
|
|
|
|
|
|
_callbacks = assign_standard_callbacks(
|
|
ffi, libuv, _Callbacks,
|
|
[
|
|
'python_sigchld_callback',
|
|
'python_timer0_callback',
|
|
'python_queue_callback',
|
|
]
|
|
)
|
|
|
|
from gevent._ffi.loop import EVENTS
|
|
GEVENT_CORE_EVENTS = EVENTS # export
|
|
|
|
from gevent.libuv import watcher as _watchers # pylint:disable=no-name-in-module
|
|
|
|
_events_to_str = _watchers._events_to_str # export
|
|
|
|
READ = libuv.UV_READABLE
|
|
WRITE = libuv.UV_WRITABLE
|
|
|
|
def get_version():
|
|
uv_bytes = ffi.string(libuv.uv_version_string())
|
|
if not isinstance(uv_bytes, str):
|
|
# Py3
|
|
uv_str = uv_bytes.decode("ascii")
|
|
else:
|
|
uv_str = uv_bytes
|
|
|
|
return 'libuv-' + uv_str
|
|
|
|
def get_header_version():
|
|
return 'libuv-%d.%d.%d' % (libuv.UV_VERSION_MAJOR, libuv.UV_VERSION_MINOR, libuv.UV_VERSION_PATCH)
|
|
|
|
def supported_backends():
|
|
return ['default']
|
|
|
|
libuv.gevent_set_uv_alloc()
|
|
|
|
@implementer(ILoop)
|
|
class loop(AbstractLoop):
|
|
|
|
# libuv parameters simply won't accept anything lower than 1ms. In
|
|
# practice, looping on gevent.sleep(0.001) takes about 0.00138 s
|
|
# (+- 0.000036s)
|
|
approx_timer_resolution = 0.001 # 1ms
|
|
|
|
# It's relatively more expensive to break from the callback loop
|
|
# because we don't do it "inline" from C, we're looping in Python
|
|
CALLBACK_CHECK_COUNT = max(AbstractLoop.CALLBACK_CHECK_COUNT, 100)
|
|
|
|
# Defines the maximum amount of time the loop will sleep waiting for IO,
|
|
# which is also the interval at which signals are checked and handled.
|
|
SIGNAL_CHECK_INTERVAL_MS = 300
|
|
|
|
error_handler = None
|
|
|
|
_CHECK_POINTER = 'uv_check_t *'
|
|
|
|
_PREPARE_POINTER = 'uv_prepare_t *'
|
|
_PREPARE_CALLBACK_SIG = "void(*)(void*)"
|
|
|
|
_TIMER_POINTER = _CHECK_POINTER # This is poorly named. It's for the callback "timer"
|
|
|
|
def __init__(self, flags=None, default=None):
|
|
AbstractLoop.__init__(self, ffi, libuv, _watchers, flags, default)
|
|
self._child_watchers = defaultdict(list)
|
|
self._io_watchers = {}
|
|
self._fork_watchers = set()
|
|
self._pid = os.getpid()
|
|
# pylint:disable-next=superfluous-parens
|
|
self._default = (self._ptr == libuv.uv_default_loop())
|
|
self._queued_callbacks = []
|
|
|
|
def _queue_callback(self, watcher_ptr, revents):
|
|
self._queued_callbacks.append((watcher_ptr, revents))
|
|
|
|
def _init_loop(self, flags, default):
|
|
if default is None:
|
|
default = True
|
|
# Unlike libev, libuv creates a new default
|
|
# loop automatically if the old default loop was
|
|
# closed.
|
|
|
|
if default:
|
|
# XXX: If the default loop had been destroyed, this
|
|
# will create a new one, but we won't destroy it
|
|
ptr = libuv.uv_default_loop()
|
|
else:
|
|
ptr = libuv.uv_loop_new()
|
|
|
|
|
|
if not ptr:
|
|
raise SystemError("Failed to get loop")
|
|
|
|
# Track whether or not any object has destroyed
|
|
# this loop. See _can_destroy_default_loop
|
|
ptr.data = self._handle_to_self
|
|
return ptr
|
|
|
|
_signal_idle = None
|
|
|
|
@property
|
|
def ptr(self):
|
|
if not self._ptr:
|
|
return None
|
|
if self._ptr and not self._ptr.data:
|
|
# Another instance of the Python loop destroyed
|
|
# the C loop. It was probably the default.
|
|
self._ptr = None
|
|
return self._ptr
|
|
|
|
def _init_and_start_check(self):
|
|
libuv.uv_check_init(self.ptr, self._check)
|
|
libuv.uv_check_start(self._check, libuv.python_check_callback)
|
|
libuv.uv_unref(self._check)
|
|
|
|
# We also have to have an idle watcher to be able to handle
|
|
# signals in a timely manner. Without them, libuv won't loop again
|
|
# and call into its check and prepare handlers.
|
|
# Note that this basically forces us into a busy-loop
|
|
# XXX: As predicted, using an idle watcher causes our process
|
|
# to eat 100% CPU time. We instead use a timer with a max of a .3 second
|
|
# delay to notice signals. Note that this timeout also implements fork
|
|
# watchers, effectively.
|
|
|
|
# XXX: Perhaps we could optimize this to notice when there are other
|
|
# timers in the loop and start/stop it then. When we have a callback
|
|
# scheduled, this should also be the same and unnecessary?
|
|
# libev does takes this basic approach on Windows.
|
|
self._signal_idle = ffi.new("uv_timer_t*")
|
|
libuv.uv_timer_init(self.ptr, self._signal_idle)
|
|
self._signal_idle.data = self._handle_to_self
|
|
sig_cb = ffi.cast('void(*)(uv_timer_t*)', libuv.python_check_callback)
|
|
libuv.uv_timer_start(self._signal_idle,
|
|
sig_cb,
|
|
self.SIGNAL_CHECK_INTERVAL_MS,
|
|
self.SIGNAL_CHECK_INTERVAL_MS)
|
|
libuv.uv_unref(self._signal_idle)
|
|
|
|
def __check_and_die(self):
|
|
if not self.ptr:
|
|
# We've been destroyed during the middle of self.run().
|
|
# This method is being called into from C, and it's not
|
|
# safe to go back to C (Windows in particular can abort
|
|
# the process with "GetQueuedCompletionStatusEx: (6) The
|
|
# handle is invalid.") So switch to the parent greenlet.
|
|
getcurrent().parent.throw(LoopExit('Destroyed during run'))
|
|
|
|
def _run_callbacks(self):
|
|
self.__check_and_die()
|
|
# Manually handle fork watchers.
|
|
curpid = os.getpid()
|
|
if curpid != self._pid:
|
|
self._pid = curpid
|
|
for watcher in self._fork_watchers:
|
|
watcher._on_fork()
|
|
|
|
|
|
# The contents of queued_callbacks at this point should be timers
|
|
# that expired when the loop began along with any idle watchers.
|
|
# We need to run them so that any manual callbacks they want to schedule
|
|
# get added to the list and ran next before we go on to poll for IO.
|
|
# This is critical for libuv on linux: closing a socket schedules some manual
|
|
# callbacks to actually stop the watcher; if those don't run before
|
|
# we poll for IO, then libuv can abort the process for the closed file descriptor.
|
|
|
|
# XXX: There's still a race condition here because we may not run *all* the manual
|
|
# callbacks. We need a way to prioritize those.
|
|
|
|
# Running these before the manual callbacks lead to some
|
|
# random test failures. In test__event.TestEvent_SetThenClear
|
|
# we would get a LoopExit sometimes. The problem occurred when
|
|
# a timer expired on entering the first loop; we would process
|
|
# it there, and then process the callback that it created
|
|
# below, leaving nothing for the loop to do. Having the
|
|
# self.run() manually process manual callbacks before
|
|
# continuing solves the problem. (But we must still run callbacks
|
|
# here again.)
|
|
self._prepare_ran_callbacks = self.__run_queued_callbacks()
|
|
|
|
super(loop, self)._run_callbacks()
|
|
|
|
def _init_and_start_prepare(self):
|
|
libuv.uv_prepare_init(self.ptr, self._prepare)
|
|
libuv.uv_prepare_start(self._prepare, libuv.python_prepare_callback)
|
|
libuv.uv_unref(self._prepare)
|
|
|
|
def _init_callback_timer(self):
|
|
libuv.uv_check_init(self.ptr, self._timer0)
|
|
|
|
def _stop_callback_timer(self):
|
|
libuv.uv_check_stop(self._timer0)
|
|
|
|
def _start_callback_timer(self):
|
|
# The purpose of the callback timer is to ensure that we run
|
|
# callbacks as soon as possible on the next iteration of the event loop.
|
|
|
|
# In libev, we set a 0 duration timer with a no-op callback.
|
|
# This executes immediately *after* the IO poll is done (it
|
|
# actually determines the time that the IO poll will block
|
|
# for), so having the timer present simply spins the loop, and
|
|
# our normal prepare watcher kicks in to run the callbacks.
|
|
|
|
# In libuv, however, timers are run *first*, before prepare
|
|
# callbacks and before polling for IO. So a no-op 0 duration
|
|
# timer actually does *nothing*. (Also note that libev queues all
|
|
# watchers found during IO poll to run at the end (I think), while libuv
|
|
# runs them in uv__io_poll itself.)
|
|
|
|
# From the loop inside uv_run:
|
|
# while True:
|
|
# uv__update_time(loop);
|
|
# uv__run_timers(loop);
|
|
# # we don't use pending watchers. They are how libuv
|
|
# # implements the pipe/udp/tcp streams.
|
|
# ran_pending = uv__run_pending(loop);
|
|
# uv__run_idle(loop);
|
|
# uv__run_prepare(loop);
|
|
# ...
|
|
# uv__io_poll(loop, timeout); # <--- IO watchers run here!
|
|
# uv__run_check(loop);
|
|
|
|
# libev looks something like this (pseudo code because the real code is
|
|
# hard to read):
|
|
#
|
|
# do {
|
|
# run_fork_callbacks();
|
|
# run_prepare_callbacks();
|
|
# timeout = min(time of all timers or normal block time)
|
|
# io_poll() # <--- Only queues IO callbacks
|
|
# update_now(); calculate_expired_timers();
|
|
# run callbacks in this order: (although specificying priorities changes it)
|
|
# check
|
|
# stat
|
|
# child
|
|
# signal
|
|
# timer
|
|
# io
|
|
# }
|
|
|
|
# So instead of running a no-op and letting the side-effect of spinning
|
|
# the loop run the callbacks, we must explicitly run them here.
|
|
|
|
# If we don't, test__systemerror:TestCallback will be flaky, failing
|
|
# one time out of ~20, depending on timing.
|
|
|
|
# To get them to run immediately after this current loop,
|
|
# we use a check watcher, instead of a 0 duration timer entirely.
|
|
# If we use a 0 duration timer, we can get stuck in a timer loop.
|
|
# Python 3.6 fails in test_ftplib.py
|
|
|
|
# As a final note, if we have not yet entered the loop *at
|
|
# all*, and a timer was created with a duration shorter than
|
|
# the amount of time it took for us to enter the loop in the
|
|
# first place, it may expire and get called before our callback
|
|
# does. This could also lead to test__systemerror:TestCallback
|
|
# appearing to be flaky.
|
|
|
|
# As yet another final note, if we are currently running a
|
|
# timer callback, meaning we're inside uv__run_timers() in C,
|
|
# and the Python starts a new timer, if the Python code then
|
|
# update's the loop's time, it's possible that timer will
|
|
# expire *and be run in the same iteration of the loop*. This
|
|
# is trivial to do: In sequential code, anything after
|
|
# `gevent.sleep(0.1)` is running in a timer callback. Starting
|
|
# a new timer---e.g., another gevent.sleep() call---will
|
|
# update the time, *before* uv__run_timers exits, meaning
|
|
# other timers get a chance to run before our check or prepare
|
|
# watcher callbacks do. Therefore, we do indeed have to have a 0
|
|
# timer to run callbacks---it gets inserted before any other user
|
|
# timers---ideally, this should be especially careful about how much time
|
|
# it runs for.
|
|
|
|
# AND YET: We can't actually do that. We get timeouts that I haven't fully
|
|
# investigated if we do. Probably stuck in a timer loop.
|
|
|
|
# As a partial remedy to this, unlike libev, our timer watcher
|
|
# class doesn't update the loop time by default.
|
|
|
|
libuv.uv_check_start(self._timer0, libuv.python_timer0_callback)
|
|
|
|
|
|
def _stop_aux_watchers(self):
|
|
super(loop, self)._stop_aux_watchers()
|
|
assert self._prepare
|
|
assert self._check
|
|
assert self._signal_idle
|
|
libuv.uv_prepare_stop(self._prepare)
|
|
libuv.uv_ref(self._prepare) # Why are we doing this?
|
|
|
|
libuv.uv_check_stop(self._check)
|
|
libuv.uv_ref(self._check)
|
|
|
|
libuv.uv_timer_stop(self._signal_idle)
|
|
libuv.uv_ref(self._signal_idle)
|
|
|
|
libuv.uv_check_stop(self._timer0)
|
|
|
|
def _setup_for_run_callback(self):
|
|
self._start_callback_timer()
|
|
libuv.uv_ref(self._timer0)
|
|
|
|
def _can_destroy_loop(self, ptr):
|
|
return ptr
|
|
|
|
def __close_loop(self, ptr):
|
|
closed_failed = 1
|
|
|
|
while closed_failed:
|
|
closed_failed = libuv.uv_loop_close(ptr)
|
|
if not closed_failed:
|
|
break
|
|
|
|
if closed_failed != libuv.UV_EBUSY:
|
|
raise SystemError("Unknown close failure reason", closed_failed)
|
|
# We already closed all the handles. Run the loop
|
|
# once to let them be cut off from the loop.
|
|
ran_has_more_callbacks = libuv.uv_run(ptr, libuv.UV_RUN_ONCE)
|
|
if ran_has_more_callbacks:
|
|
libuv.uv_run(ptr, libuv.UV_RUN_NOWAIT)
|
|
|
|
|
|
def _destroy_loop(self, ptr):
|
|
# We're being asked to destroy a loop that's, potentially, at
|
|
# the time it was constructed, was the default loop. If loop
|
|
# objects were constructed more than once, it may have already
|
|
# been destroyed, though. We track this in the data member.
|
|
data = ptr.data
|
|
ptr.data = ffi.NULL
|
|
try:
|
|
if data:
|
|
libuv.uv_stop(ptr)
|
|
libuv.gevent_close_all_handles(ptr)
|
|
finally:
|
|
ptr.data = ffi.NULL
|
|
|
|
try:
|
|
if data:
|
|
self.__close_loop(ptr)
|
|
finally:
|
|
# Destroy the native resources *after* we have closed
|
|
# the loop. If we do it before, walking the handles
|
|
# attached to the loop is likely to segfault.
|
|
# Note that these may have been closed already if the default loop was shared.
|
|
if data:
|
|
libuv.gevent_zero_check(self._check)
|
|
libuv.gevent_zero_check(self._timer0)
|
|
libuv.gevent_zero_prepare(self._prepare)
|
|
libuv.gevent_zero_timer(self._signal_idle)
|
|
libuv.gevent_zero_loop(ptr)
|
|
|
|
del self._check
|
|
del self._prepare
|
|
del self._signal_idle
|
|
del self._timer0
|
|
|
|
# Destroy any watchers we're still holding on to.
|
|
del self._io_watchers
|
|
del self._fork_watchers
|
|
del self._child_watchers
|
|
|
|
_HandleState = namedtuple("HandleState",
|
|
['handle',
|
|
'type',
|
|
'watcher',
|
|
'ref',
|
|
'active',
|
|
'closing'])
|
|
def debug(self):
|
|
"""
|
|
Return all the handles that are open and their ref status.
|
|
"""
|
|
if not self.ptr:
|
|
return ["Loop has been destroyed"]
|
|
|
|
handle_state = self._HandleState
|
|
handles = []
|
|
|
|
# XXX: Convert this to a modern callback.
|
|
def walk(handle, _arg):
|
|
data = handle.data
|
|
if data:
|
|
watcher = ffi.from_handle(data)
|
|
else:
|
|
watcher = None
|
|
handles.append(handle_state(handle,
|
|
ffi.string(libuv.uv_handle_type_name(handle.type)),
|
|
watcher,
|
|
libuv.uv_has_ref(handle),
|
|
libuv.uv_is_active(handle),
|
|
libuv.uv_is_closing(handle)))
|
|
|
|
libuv.uv_walk(self.ptr,
|
|
ffi.callback("void(*)(uv_handle_t*,void*)",
|
|
walk),
|
|
ffi.NULL)
|
|
return handles
|
|
|
|
def ref(self):
|
|
pass
|
|
|
|
def unref(self):
|
|
# XXX: Called by _run_callbacks.
|
|
pass
|
|
|
|
def break_(self, how=None):
|
|
if self.ptr:
|
|
libuv.uv_stop(self.ptr)
|
|
|
|
def reinit(self):
|
|
# TODO: How to implement? We probably have to simply
|
|
# re-__init__ this whole class? Does it matter?
|
|
# OR maybe we need to uv_walk() and close all the handles?
|
|
|
|
# XXX: libuv < 1.12 simply CANNOT handle a fork unless you immediately
|
|
# exec() in the child. There are multiple calls to abort() that
|
|
# will kill the child process:
|
|
# - The OS X poll implementation (kqueue) aborts on an error return
|
|
# value; since kqueue FDs can't be inherited, then the next call
|
|
# to kqueue in the child will fail and get aborted; fork() is likely
|
|
# to be called during the gevent loop, meaning we're deep inside the
|
|
# runloop already, so we can't even close the loop that we're in:
|
|
# it's too late, the next call to kqueue is already scheduled.
|
|
# - The threadpool, should it be in use, also aborts
|
|
# (https://github.com/joyent/libuv/pull/1136)
|
|
# - There global shared state that breaks signal handling
|
|
# and leads to an abort() in the child, EVEN IF the loop in the parent
|
|
# had already been closed
|
|
# (https://github.com/joyent/libuv/issues/1405)
|
|
|
|
# In 1.12, the uv_loop_fork function was added (by gevent!)
|
|
libuv.uv_loop_fork(self.ptr)
|
|
|
|
_prepare_ran_callbacks = False
|
|
|
|
def __run_queued_callbacks(self):
|
|
if not self._queued_callbacks:
|
|
return False
|
|
|
|
cbs = self._queued_callbacks[:]
|
|
del self._queued_callbacks[:]
|
|
|
|
for watcher_ptr, arg in cbs:
|
|
handle = watcher_ptr.data
|
|
if not handle:
|
|
# It's been stopped and possibly closed
|
|
assert not libuv.uv_is_active(watcher_ptr)
|
|
continue
|
|
val = _callbacks.python_callback(handle, arg)
|
|
if val == -1: # Failure.
|
|
_callbacks.python_handle_error(handle, arg)
|
|
elif val == 1: # Success, and we may need to close the Python watcher.
|
|
if not libuv.uv_is_active(watcher_ptr):
|
|
# The callback closed the native watcher resources. Good.
|
|
# It's *supposed* to also reset the .data handle to NULL at
|
|
# that same time. If it resets it to something else, we're
|
|
# re-using the same watcher object, and that's not correct either.
|
|
# On Windows in particular, if the .data handle is changed because
|
|
# the IO multiplexer is being restarted, trying to dereference the
|
|
# *old* handle can crash with an FFI error.
|
|
handle_after_callback = watcher_ptr.data
|
|
try:
|
|
if handle_after_callback and handle_after_callback == handle:
|
|
_callbacks.python_stop(handle_after_callback)
|
|
finally:
|
|
watcher_ptr.data = ffi.NULL
|
|
return True
|
|
|
|
|
|
def run(self, nowait=False, once=False):
|
|
# we can only respect one flag or the other.
|
|
# nowait takes precedence because it can't block
|
|
mode = libuv.UV_RUN_DEFAULT
|
|
if once:
|
|
mode = libuv.UV_RUN_ONCE
|
|
if nowait:
|
|
mode = libuv.UV_RUN_NOWAIT
|
|
|
|
if mode == libuv.UV_RUN_DEFAULT:
|
|
while self._ptr and self._ptr.data:
|
|
# This is here to better preserve order guarantees.
|
|
# See _run_callbacks for details.
|
|
|
|
# It may get run again from the prepare watcher, so
|
|
# potentially we could take twice as long as the
|
|
# switch interval.
|
|
# If we have *lots* of callbacks to run, we may not actually
|
|
# get through them all before we're requested to poll for IO;
|
|
# so in that case, just spin the loop once (UV_RUN_NOWAIT) and
|
|
# go again.
|
|
self._run_callbacks()
|
|
self._prepare_ran_callbacks = False
|
|
|
|
# UV_RUN_ONCE will poll for IO, blocking for up to the time needed
|
|
# for the next timer to expire. Worst case, that's our _signal_idle
|
|
# timer, about 1/3 second. UV_RUN_ONCE guarantees that some forward progress
|
|
# is made, either by an IO watcher or a timer.
|
|
#
|
|
# In contrast, UV_RUN_NOWAIT makes no such guarantee, it only polls for IO once and
|
|
# immediately returns; it does not update the loop time or timers after
|
|
# polling for IO.
|
|
run_mode = (
|
|
libuv.UV_RUN_ONCE
|
|
if not self._callbacks and not self._queued_callbacks
|
|
else libuv.UV_RUN_NOWAIT
|
|
)
|
|
|
|
ran_status = libuv.uv_run(self._ptr, run_mode)
|
|
# Note that we run queued callbacks when the prepare watcher runs,
|
|
# thus accounting for timers that expired before polling for IO,
|
|
# and idle watchers. This next call should get IO callbacks and
|
|
# callbacks from timers that expired *after* polling for IO.
|
|
ran_callbacks = self.__run_queued_callbacks()
|
|
|
|
if not ran_status and not ran_callbacks and not self._prepare_ran_callbacks:
|
|
# A return of 0 means there are no referenced and
|
|
# active handles. The loop is over.
|
|
# If we didn't run any callbacks, then we couldn't schedule
|
|
# anything to switch in the future, so there's no point
|
|
# running again.
|
|
return ran_status
|
|
return 0 # Somebody closed the loop
|
|
|
|
result = libuv.uv_run(self._ptr, mode)
|
|
self.__run_queued_callbacks()
|
|
return result
|
|
|
|
def now(self):
|
|
self.__check_and_die()
|
|
# libuv's now is expressed as an integer number of
|
|
# milliseconds, so to get it compatible with time.time units
|
|
# that this method is supposed to return, we have to divide by 1000.0
|
|
now = libuv.uv_now(self.ptr)
|
|
return now / 1000.0
|
|
|
|
def update_now(self):
|
|
self.__check_and_die()
|
|
libuv.uv_update_time(self.ptr)
|
|
|
|
def fileno(self):
|
|
if self.ptr:
|
|
fd = libuv.uv_backend_fd(self._ptr)
|
|
if fd >= 0:
|
|
return fd
|
|
|
|
_sigchld_watcher = None
|
|
_sigchld_callback_ffi = None
|
|
|
|
def install_sigchld(self):
|
|
if not self.default:
|
|
return
|
|
|
|
if self._sigchld_watcher:
|
|
return
|
|
|
|
self._sigchld_watcher = ffi.new('uv_signal_t*')
|
|
libuv.uv_signal_init(self.ptr, self._sigchld_watcher)
|
|
self._sigchld_watcher.data = self._handle_to_self
|
|
# Don't let this keep the loop alive
|
|
libuv.uv_unref(self._sigchld_watcher)
|
|
|
|
libuv.uv_signal_start(self._sigchld_watcher,
|
|
libuv.python_sigchld_callback,
|
|
signal.SIGCHLD)
|
|
|
|
def reset_sigchld(self):
|
|
if not self.default or not self._sigchld_watcher:
|
|
return
|
|
|
|
libuv.uv_signal_stop(self._sigchld_watcher)
|
|
# Must go through this to manage the memory lifetime
|
|
# correctly. Alternately, we could just stop it and restart
|
|
# it in install_sigchld?
|
|
_watchers.watcher._watcher_ffi_close(self._sigchld_watcher)
|
|
del self._sigchld_watcher
|
|
|
|
|
|
def _sigchld_callback(self):
|
|
# Signals can arrive at (relatively) any time. To eliminate
|
|
# race conditions, and behave more like libev, we "queue"
|
|
# sigchld to run when we run callbacks.
|
|
while True:
|
|
try:
|
|
pid, status, _usage = os.wait3(os.WNOHANG)
|
|
except OSError:
|
|
# Python 3 raises ChildProcessError
|
|
break
|
|
|
|
if pid == 0:
|
|
break
|
|
children_watchers = self._child_watchers.get(pid, []) + self._child_watchers.get(0, [])
|
|
for watcher in children_watchers:
|
|
self.run_callback(watcher._set_waitpid_status, pid, status)
|
|
|
|
# Don't invoke child watchers for 0 more than once
|
|
self._child_watchers[0] = []
|
|
|
|
def _register_child_watcher(self, watcher):
|
|
self._child_watchers[watcher._pid].append(watcher)
|
|
|
|
def _unregister_child_watcher(self, watcher):
|
|
try:
|
|
# stop() should be idempotent
|
|
self._child_watchers[watcher._pid].remove(watcher)
|
|
except ValueError:
|
|
pass
|
|
|
|
# Now's a good time to clean up any dead watchers we don't need
|
|
# anymore
|
|
for pid in list(self._child_watchers):
|
|
if not self._child_watchers[pid]:
|
|
del self._child_watchers[pid]
|
|
|
|
def io(self, fd, events, ref=True, priority=None):
|
|
# We rely on hard references here and explicit calls to
|
|
# close() on the returned object to correctly manage
|
|
# the watcher lifetimes.
|
|
|
|
io_watchers = self._io_watchers
|
|
try:
|
|
io_watcher = io_watchers[fd]
|
|
assert io_watcher._multiplex_watchers, ("IO Watcher %s unclosed but should be dead" % io_watcher)
|
|
except KeyError:
|
|
# Start the watcher with just the events that we're interested in.
|
|
# as multiplexers are added, the real event mask will be updated to keep in sync.
|
|
# If we watch for too much, we get spurious wakeups and busy loops.
|
|
io_watcher = self._watchers.io(self, fd, 0)
|
|
io_watchers[fd] = io_watcher
|
|
io_watcher._no_more_watchers = lambda: delitem(io_watchers, fd)
|
|
|
|
return io_watcher.multiplex(events)
|
|
|
|
def prepare(self, ref=True, priority=None):
|
|
# We run arbitrary code in python_prepare_callback. That could switch
|
|
# greenlets. If it does that while also manipulating the active prepare
|
|
# watchers, we could corrupt the process state, since the prepare watcher
|
|
# queue is iterated on the stack (on unix). We could workaround this by implementing
|
|
# prepare watchers in pure Python.
|
|
# See https://github.com/gevent/gevent/issues/1126
|
|
raise TypeError("prepare watchers are not currently supported in libuv. "
|
|
"If you need them, please contact the maintainers.")
|