#!/usr/bin/env python
#
# Copyright 2012 Facebook
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
"""KQueue-based IOLoop implementation for BSD/Mac systems."""
from __future__ import absolute_import, division, print_function, with_statement
import select
from tornado.ioloop import IOLoop, PollIOLoop
assert hasattr(select, 'kqueue'), 'kqueue not supported'
class _KQueue(object):
"""A kqueue-based event loop for BSD/Mac systems."""
def __init__(self):
self._kqueue = select.kqueue()
self._active = {}
def fileno(self):
return self._kqueue.fileno()
def close(self):
self._kqueue.close()
def register(self, fd, events):
if fd in self._active:
raise IOError("fd %s already registered" % fd)
self._control(fd, events, select.KQ_EV_ADD)
self._active[fd] = events
def modify(self, fd, events):
self.unregister(fd)
self.register(fd, events)
def unregister(self, fd):
events = self._active.pop(fd)
self._control(fd, events, select.KQ_EV_DELETE)
def _control(self, fd, events, flags):
kevents = []
if events & IOLoop.WRITE:
kevents.append(select.kevent(
fd, filter=select.KQ_FILTER_WRITE, flags=flags))
if events & IOLoop.READ:
kevents.append(select.kevent(
fd, filter=select.KQ_FILTER_READ, flags=flags))
# Even though control() takes a list, it seems to return EINVAL
# on Mac OS X (10.6) when there is more than one event in the list.
for kevent in kevents:
self._kqueue.control([kevent], 0)
def poll(self, timeout):
kevents = self._kqueue.control(None, 1000, timeout)
events = {}
for kevent in kevents:
fd = kevent.ident
if kevent.filter == select.KQ_FILTER_READ:
events[fd] = events.get(fd, 0) | IOLoop.READ
if kevent.filter == select.KQ_FILTER_WRITE:
if kevent.flags & select.KQ_EV_EOF:
# If an asynchronous connection is refused, kqueue
# returns a write event with the EOF flag set.
# Turn this into an error for consistency with the
# other IOLoop implementations.
# Note that for read events, EOF may be returned before
# all data has been consumed from the socket buffer,
# so we only check for EOF on write events.
events[fd] = IOLoop.ERROR
else:
events[fd] = events.get(fd, 0) | IOLoop.WRITE
if kevent.flags & select.KQ_EV_ERROR:
events[fd] = events.get(fd, 0) | IOLoop.ERROR
return events.items()
class KQueueIOLoop(PollIOLoop):
def initialize(self, **kwargs):
super(KQueueIOLoop, self).initialize(impl=_KQueue(), **kwargs)
