#!/usr/bin/python
# -*- coding: utf-8 -*-
#
# Copyright 2013-2015 clowwindy
#
# 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.
# from ssloop
# https://github.com/clowwindy/ssloop
from __future__ import absolute_import, division, print_function, \
with_statement
import os
import time
import socket
import select
import errno
import logging
from collections import defaultdict
from shadowsocks import shell
__all__ = ['EventLoop', 'POLL_NULL', 'POLL_IN', 'POLL_OUT', 'POLL_ERR',
'POLL_HUP', 'POLL_NVAL', 'EVENT_NAMES']
POLL_NULL = 0x00
POLL_IN = 0x01
POLL_OUT = 0x04
POLL_ERR = 0x08
POLL_HUP = 0x10
POLL_NVAL = 0x20
EVENT_NAMES = {
POLL_NULL: 'POLL_NULL',
POLL_IN: 'POLL_IN',
POLL_OUT: 'POLL_OUT',
POLL_ERR: 'POLL_ERR',
POLL_HUP: 'POLL_HUP',
POLL_NVAL: 'POLL_NVAL',
}
# we check timeouts every TIMEOUT_PRECISION seconds
TIMEOUT_PRECISION = 10
class KqueueLoop(object):
MAX_EVENTS = 1024
def __init__(self):
self._kqueue = select.kqueue()
self._fds = {}
def _control(self, fd, mode, flags):
events = []
if mode & POLL_IN:
events.append(select.kevent(fd, select.KQ_FILTER_READ, flags))
if mode & POLL_OUT:
events.append(select.kevent(fd, select.KQ_FILTER_WRITE, flags))
for e in events:
self._kqueue.control([e], 0)
def poll(self, timeout):
if timeout < 0:
timeout = None # kqueue behaviour
events = self._kqueue.control(None, KqueueLoop.MAX_EVENTS, timeout)
results = defaultdict(lambda: POLL_NULL)
for e in events:
fd = e.ident
if e.filter == select.KQ_FILTER_READ:
results[fd] |= POLL_IN
elif e.filter == select.KQ_FILTER_WRITE:
results[fd] |= POLL_OUT
return results.items()
def register(self, fd, mode):
self._fds[fd] = mode
self._control(fd, mode, select.KQ_EV_ADD)
def unregister(self, fd):
self._control(fd, self._fds[fd], select.KQ_EV_DELETE)
del self._fds[fd]
def modify(self, fd, mode):
self.unregister(fd)
self.register(fd, mode)
def close(self):
self._kqueue.close()
class SelectLoop(object):
def __init__(self):
self._r_list = set()
self._w_list = set()
self._x_list = set()
def poll(self, timeout):
r, w, x = select.select(self._r_list, self._w_list, self._x_list,
timeout)
results = defaultdict(lambda: POLL_NULL)
for p in [(r, POLL_IN), (w, POLL_OUT), (x, POLL_ERR)]:
for fd in p[0]:
results[fd] |= p[1]
return results.items()
def register(self, fd, mode):
if mode & POLL_IN:
self._r_list.add(fd)
if mode & POLL_OUT:
self._w_list.add(fd)
if mode & POLL_ERR:
self._x_list.add(fd)
def unregister(self, fd):
if fd in self._r_list:
self._r_list.remove(fd)
if fd in self._w_list:
self._w_list.remove(fd)
if fd in self._x_list:
self._x_list.remove(fd)
def modify(self, fd, mode):
self.unregister(fd)
self.register(fd, mode)
def close(self):
pass
class EventLoop(object):
def __init__(self):
if hasattr(select, 'epoll'):
self._impl = select.epoll()
model = 'epoll'
elif hasattr(select, 'kqueue'):
self._impl = KqueueLoop()
model = 'kqueue'
elif hasattr(select, 'select'):
self._impl = SelectLoop()
model = 'select'
else:
raise Exception('can not find any available functions in select '
'package')
self._fdmap = {} # (f, handler)
self._last_time = time.time()
self._periodic_callbacks = []
self._stopping = False
logging.debug('using event model: %s', model)
def poll(self, timeout=None):
events = self._impl.poll(timeout)
return [(self._fdmap[fd][0], fd, event) for fd, event in events]
def add(self, f, mode, handler):
fd = f.fileno()
self._fdmap[fd] = (f, handler)
self._impl.register(fd, mode)
def remove(self, f):
fd = f.fileno()
del self._fdmap[fd]
self._impl.unregister(fd)
def add_periodic(self, callback):
self._periodic_callbacks.append(callback)
def remove_periodic(self, callback):
self._periodic_callbacks.remove(callback)
def modify(self, f, mode):
fd = f.fileno()
self._impl.modify(fd, mode)
def stop(self):
self._stopping = True
def run(self):
events = []
while not self._stopping:
asap = False
try:
events = self.poll(TIMEOUT_PRECISION)
except (OSError, IOError) as e:
if errno_from_exception(e) in (errno.EPIPE, errno.EINTR):
# EPIPE: Happens when the client closes the connection
# EINTR: Happens when received a signal
# handles them as soon as possible
asap = True
logging.debug('poll:%s', e)
else:
logging.error('poll:%s', e)
import traceback
traceback.print_exc()
continue
for sock, fd, event in events:
handler = self._fdmap.get(fd, None)
if handler is not None:
handler = handler[1]
try:
handler.handle_event(sock, fd, event)
except (OSError, IOError) as e:
shell.print_exception(e)
now = time.time()
if asap or now - self._last_time >= TIMEOUT_PRECISION:
for callback in self._periodic_callbacks:
callback()
self._last_time = now
def __del__(self):
self._impl.close()
# from tornado
def errno_from_exception(e):
"""Provides the errno from an Exception object.
There are cases that the errno attribute was not set so we pull
the errno out of the args but if someone instatiates an Exception
without any args you will get a tuple error. So this function
abstracts all that behavior to give you a safe way to get the
errno.
"""
if hasattr(e, 'errno'):
return e.errno
elif e.args:
return e.args[0]
else:
return None
# from tornado
def get_sock_error(sock):
error_number = sock.getsockopt(socket.SOL_SOCKET, socket.SO_ERROR)
return socket.error(error_number, os.strerror(error_number))
