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  $   ˆl–Ãa¾”d*j"TÚzã@¸Ø”Å£Â„Á¿Ä ?÷     # -*- Mode: Python -*-
#   Id: asyncore.py,v 2.51 2000/09/07 22:29:26 rushing Exp
#   Author: Sam Rushing <rushing@nightmare.com>

# ======================================================================
# Copyright 1996 by Sam Rushing
#
#                         All Rights Reserved
#
# Permission to use, copy, modify, and distribute this software and
# its documentation for any purpose and without fee is hereby
# granted, provided that the above copyright notice appear in all
# copies and that both that copyright notice and this permission
# notice appear in supporting documentation, and that the name of Sam
# Rushing not be used in advertising or publicity pertaining to
# distribution of the software without specific, written prior
# permission.
#
# SAM RUSHING DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
# INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN
# NO EVENT SHALL SAM RUSHING BE LIABLE FOR ANY SPECIAL, INDIRECT OR
# CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
# OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
# NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
# CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
# ======================================================================

"""Basic infrastructure for asynchronous socket service clients and servers.

There are only two ways to have a program on a single processor do "more
than one thing at a time".  Multi-threaded programming is the simplest and
most popular way to do it, but there is another very different technique,
that lets you have nearly all the advantages of multi-threading, without
actually using multiple threads. it's really only practical if your program
is largely I/O bound. If your program is CPU bound, then pre-emptive
scheduled threads are probably what you really need. Network servers are
rarely CPU-bound, however.

If your operating system supports the select() system call in its I/O
library (and nearly all do), then you can use it to juggle multiple
communication channels at once; doing other work while your I/O is taking
place in the "background."  Although this strategy can seem strange and
complex, especially at first, it is in many ways easier to understand and
control than multi-threaded programming. The module documented here solves
many of the difficult problems for you, making the task of building
sophisticated high-performance network servers and clients a snap.
"""

import select
import socket
import sys
import time
import warnings

import os
from errno import EALREADY, EINPROGRESS, EWOULDBLOCK, ECONNRESET, EINVAL, \
     ENOTCONN, ESHUTDOWN, EISCONN, EBADF, ECONNABORTED, EPIPE, EAGAIN, \
     errorcode

_DISCONNECTED = frozenset({ECONNRESET, ENOTCONN, ESHUTDOWN, ECONNABORTED, EPIPE,
                           EBADF})

try:
    socket_map
except NameError:
    socket_map = {}

def _strerror(err):
    try:
        return os.strerror(err)
    except (ValueError, OverflowError, NameError):
        if err in errorcode:
            return errorcode[err]
        return "Unknown error %s" %err

class ExitNow(Exception):
    pass

_reraised_exceptions = (ExitNow, KeyboardInterrupt, SystemExit)

def read(obj):
    try:
        obj.handle_read_event()
    except _reraised_exceptions:
        raise
    except:
        obj.handle_error()

def write(obj):
    try:
        obj.handle_write_event()
    except _reraised_exceptions:
        raise
    except:
        obj.handle_error()

def _exception(obj):
    try:
        obj.handle_expt_event()
    except _reraised_exceptions:
        raise
    except:
        obj.handle_error()

def readwrite(obj, flags):
    try:
        if flags & select.POLLIN:
            obj.handle_read_event()
        if flags & select.POLLOUT:
            obj.handle_write_event()
        if flags & select.POLLPRI:
            obj.handle_expt_event()
        if flags & (select.POLLHUP | select.POLLERR | select.POLLNVAL):
            obj.handle_close()
    except OSError as e: