mirror of https://github.com/python/cpython
475 lines
12 KiB
Python
475 lines
12 KiB
Python
# -*- Mode: Python; tab-width: 4 -*-
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# Id: asyncore.py,v 2.40 1999/05/27 04:08:25 rushing Exp
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# Author: Sam Rushing <rushing@nightmare.com>
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# ======================================================================
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# Copyright 1996 by Sam Rushing
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#
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# All Rights Reserved
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#
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# Permission to use, copy, modify, and distribute this software and
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# its documentation for any purpose and without fee is hereby
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# granted, provided that the above copyright notice appear in all
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# copies and that both that copyright notice and this permission
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# notice appear in supporting documentation, and that the name of Sam
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# Rushing not be used in advertising or publicity pertaining to
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# distribution of the software without specific, written prior
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# permission.
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#
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# SAM RUSHING DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
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# INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN
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# NO EVENT SHALL SAM RUSHING BE LIABLE FOR ANY SPECIAL, INDIRECT OR
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# CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
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# OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
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# NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
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# CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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# ======================================================================
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"""Basic infrastructure for asynchronous socket service clients and servers.
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There are only two ways to have a program on a single processor do "more
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than one thing at a time". Multi-threaded programming is the simplest and
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most popular way to do it, but there is another very different technique,
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that lets you have nearly all the advantages of multi-threading, without
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actually using multiple threads. it's really only practical if your program
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is largely I/O bound. If your program is CPU bound, then pre-emptive
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scheduled threads are probably what you really need. Network servers are
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rarely CPU-bound, however.
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If your operating system supports the select() system call in its I/O
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library (and nearly all do), then you can use it to juggle multiple
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communication channels at once; doing other work while your I/O is taking
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place in the "background." Although this strategy can seem strange and
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complex, especially at first, it is in many ways easier to understand and
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control than multi-threaded programming. The module documented here solves
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many of the difficult problems for you, making the task of building
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sophisticated high-performance network servers and clients a snap.
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"""
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import select
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import socket
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import string
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import sys
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import os
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if os.name == 'nt':
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EWOULDBLOCK = 10035
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EINPROGRESS = 10036
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EALREADY = 10037
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ECONNRESET = 10054
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ENOTCONN = 10057
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ESHUTDOWN = 10058
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else:
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from errno import EALREADY, EINPROGRESS, EWOULDBLOCK, ECONNRESET, ENOTCONN, ESHUTDOWN
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socket_map = {}
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def poll (timeout=0.0):
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if socket_map:
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r = []; w = []; e = []
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for s in socket_map.keys():
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if s.readable():
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r.append (s)
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if s.writable():
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w.append (s)
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(r,w,e) = select.select (r,w,e, timeout)
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for x in r:
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try:
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x.handle_read_event()
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except:
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x.handle_error()
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for x in w:
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try:
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x.handle_write_event()
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except:
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x.handle_error()
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def poll2 (timeout=0.0):
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import poll
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# timeout is in milliseconds
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timeout = int(timeout*1000)
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if socket_map:
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fd_map = {}
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for s in socket_map.keys():
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fd_map[s.fileno()] = s
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l = []
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for fd, s in fd_map.items():
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flags = 0
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if s.readable():
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flags = poll.POLLIN
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if s.writable():
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flags = flags | poll.POLLOUT
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if flags:
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l.append (fd, flags)
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r = poll.poll (l, timeout)
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for fd, flags in r:
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s = fd_map[fd]
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try:
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if (flags & poll.POLLIN):
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s.handle_read_event()
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if (flags & poll.POLLOUT):
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s.handle_write_event()
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if (flags & poll.POLLERR):
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s.handle_expt_event()
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except:
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s.handle_error()
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def loop (timeout=30.0, use_poll=0):
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if use_poll:
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poll_fun = poll2
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else:
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poll_fun = poll
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while socket_map:
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poll_fun (timeout)
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class dispatcher:
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debug = 0
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connected = 0
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accepting = 0
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closing = 0
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addr = None
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def __init__ (self, sock=None):
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if sock:
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self.set_socket (sock)
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# I think it should inherit this anyway
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self.socket.setblocking (0)
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self.connected = 1
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def __repr__ (self):
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try:
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status = []
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if self.accepting and self.addr:
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status.append ('listening')
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elif self.connected:
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status.append ('connected')
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if self.addr:
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status.append ('%s:%d' % self.addr)
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return '<%s %s at %x>' % (
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self.__class__.__name__,
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string.join (status, ' '),
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id(self)
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)
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except:
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try:
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ar = repr(self.addr)
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except:
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ar = 'no self.addr!'
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return '<__repr__ (self) failed for object at %x (addr=%s)>' % (id(self),ar)
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def add_channel (self):
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if __debug__:
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self.log ('adding channel %s' % self)
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socket_map [self] = 1
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def del_channel (self):
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if socket_map.has_key (self):
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if __debug__:
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self.log ('closing channel %d:%s' % (self.fileno(), self))
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del socket_map [self]
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def create_socket (self, family, type):
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self.family_and_type = family, type
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self.socket = socket.socket (family, type)
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self.socket.setblocking(0)
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self.add_channel()
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def set_socket (self, socket):
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# This is done so we can be called safely from __init__
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self.__dict__['socket'] = socket
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self.add_channel()
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def set_reuse_addr (self):
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# try to re-use a server port if possible
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try:
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self.socket.setsockopt (
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socket.SOL_SOCKET, socket.SO_REUSEADDR,
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self.socket.getsockopt (socket.SOL_SOCKET, socket.SO_REUSEADDR) | 1
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)
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except:
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pass
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# ==================================================
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# predicates for select()
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# these are used as filters for the lists of sockets
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# to pass to select().
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# ==================================================
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def readable (self):
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return 1
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if os.name == 'mac':
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# The macintosh will select a listening socket for
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# write if you let it. What might this mean?
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def writable (self):
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return not self.accepting
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else:
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def writable (self):
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return 1
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# ==================================================
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# socket object methods.
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# ==================================================
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def listen (self, num):
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self.accepting = 1
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if os.name == 'nt' and num > 5:
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num = 1
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return self.socket.listen (num)
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def bind (self, addr):
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self.addr = addr
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return self.socket.bind (addr)
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def connect (self, address):
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self.connected = 0
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try:
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self.socket.connect (address)
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except socket.error, why:
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if why[0] in (EINPROGRESS, EALREADY, EWOULDBLOCK):
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return
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else:
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raise socket.error, why
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self.connected = 1
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self.handle_connect()
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def accept (self):
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try:
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conn, addr = self.socket.accept()
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return conn, addr
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except socket.error, why:
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if why[0] == EWOULDBLOCK:
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pass
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else:
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raise socket.error, why
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def send (self, data):
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try:
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result = self.socket.send (data)
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return result
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except socket.error, why:
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if why[0] == EWOULDBLOCK:
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return 0
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else:
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raise socket.error, why
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return 0
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def recv (self, buffer_size):
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try:
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data = self.socket.recv (buffer_size)
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if not data:
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# a closed connection is indicated by signaling
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# a read condition, and having recv() return 0.
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self.handle_close()
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return ''
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else:
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return data
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except socket.error, why:
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# winsock sometimes throws ENOTCONN
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if why[0] in [ECONNRESET, ENOTCONN, ESHUTDOWN]:
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self.handle_close()
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return ''
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else:
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raise socket.error, why
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def close (self):
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self.del_channel()
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self.socket.close()
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# cheap inheritance, used to pass all other attribute
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# references to the underlying socket object.
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# NOTE: this may be removed soon for performance reasons.
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def __getattr__ (self, attr):
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return getattr (self.socket, attr)
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def log (self, message):
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print 'log:', message
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def handle_read_event (self):
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if self.accepting:
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# for an accepting socket, getting a read implies
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# that we are connected
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if not self.connected:
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self.connected = 1
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self.handle_accept()
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elif not self.connected:
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self.handle_connect()
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self.connected = 1
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self.handle_read()
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else:
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self.handle_read()
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def handle_write_event (self):
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# getting a write implies that we are connected
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if not self.connected:
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self.handle_connect()
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self.connected = 1
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self.handle_write()
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def handle_expt_event (self):
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self.handle_expt()
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def handle_error (self):
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(file,fun,line), t, v, tbinfo = compact_traceback()
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# sometimes a user repr method will crash.
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try:
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self_repr = repr (self)
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except:
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self_repr = '<__repr__ (self) failed for object at %0x>' % id(self)
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print (
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'uncaptured python exception, closing channel %s (%s:%s %s)' % (
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self_repr,
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t,
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v,
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tbinfo
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)
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)
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self.close()
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def handle_expt (self):
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if __debug__:
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self.log ('unhandled exception')
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def handle_read (self):
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if __debug__:
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self.log ('unhandled read event')
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def handle_write (self):
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if __debug__:
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self.log ('unhandled write event')
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def handle_connect (self):
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if __debug__:
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self.log ('unhandled connect event')
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def handle_accept (self):
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if __debug__:
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self.log ('unhandled accept event')
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def handle_close (self):
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if __debug__:
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self.log ('unhandled close event')
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self.close()
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# ---------------------------------------------------------------------------
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# adds simple buffered output capability, useful for simple clients.
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# [for more sophisticated usage use asynchat.async_chat]
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# ---------------------------------------------------------------------------
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class dispatcher_with_send (dispatcher):
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def __init__ (self, sock=None):
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dispatcher.__init__ (self, sock)
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self.out_buffer = ''
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def initiate_send (self):
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num_sent = 0
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num_sent = dispatcher.send (self, self.out_buffer[:512])
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self.out_buffer = self.out_buffer[num_sent:]
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def handle_write (self):
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self.initiate_send()
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def writable (self):
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return (not self.connected) or len(self.out_buffer)
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def send (self, data):
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if self.debug:
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self.log ('sending %s' % repr(data))
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self.out_buffer = self.out_buffer + data
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self.initiate_send()
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# ---------------------------------------------------------------------------
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# used for debugging.
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# ---------------------------------------------------------------------------
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def compact_traceback ():
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t,v,tb = sys.exc_info()
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tbinfo = []
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while 1:
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tbinfo.append (
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tb.tb_frame.f_code.co_filename,
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tb.tb_frame.f_code.co_name,
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str(tb.tb_lineno)
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)
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tb = tb.tb_next
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if not tb:
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break
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# just to be safe
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del tb
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file, function, line = tbinfo[-1]
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info = '[' + string.join (
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map (
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lambda x: string.join (x, '|'),
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tbinfo
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),
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'] ['
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) + ']'
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return (file, function, line), t, v, info
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def close_all ():
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global socket_map
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for x in socket_map.keys():
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x.socket.close()
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socket_map.clear()
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# Asynchronous File I/O:
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#
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# After a little research (reading man pages on various unixen, and
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# digging through the linux kernel), I've determined that select()
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# isn't meant for doing doing asynchronous file i/o.
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# Heartening, though - reading linux/mm/filemap.c shows that linux
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# supports asynchronous read-ahead. So _MOST_ of the time, the data
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# will be sitting in memory for us already when we go to read it.
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#
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# What other OS's (besides NT) support async file i/o? [VMS?]
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#
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# Regardless, this is useful for pipes, and stdin/stdout...
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import os
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if os.name == 'posix':
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import fcntl
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import FCNTL
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class file_wrapper:
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# here we override just enough to make a file
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# look like a socket for the purposes of asyncore.
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def __init__ (self, fd):
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self.fd = fd
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def recv (self, *args):
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return apply (os.read, (self.fd,)+args)
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def write (self, *args):
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return apply (os.write, (self.fd,)+args)
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def close (self):
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return os.close (self.fd)
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def fileno (self):
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return self.fd
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class file_dispatcher (dispatcher):
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def __init__ (self, fd):
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dispatcher.__init__ (self)
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self.connected = 1
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# set it to non-blocking mode
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flags = fcntl.fcntl (fd, FCNTL.F_GETFL, 0)
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flags = flags | FCNTL.O_NONBLOCK
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fcntl.fcntl (fd, FCNTL.F_SETFL, flags)
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self.set_file (fd)
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def set_file (self, fd):
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self.socket = file_wrapper (fd)
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self.add_channel()
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