/usr/lib/python3.5/asynchat.py is in libpython3.5-stdlib 3.5.3-1+deb9u1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 | # -*- Mode: Python; tab-width: 4 -*-
# Id: asynchat.py,v 2.26 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.
# ======================================================================
r"""A class supporting chat-style (command/response) protocols.
This class adds support for 'chat' style protocols - where one side
sends a 'command', and the other sends a response (examples would be
the common internet protocols - smtp, nntp, ftp, etc..).
The handle_read() method looks at the input stream for the current
'terminator' (usually '\r\n' for single-line responses, '\r\n.\r\n'
for multi-line output), calling self.found_terminator() on its
receipt.
for example:
Say you build an async nntp client using this class. At the start
of the connection, you'll have self.terminator set to '\r\n', in
order to process the single-line greeting. Just before issuing a
'LIST' command you'll set it to '\r\n.\r\n'. The output of the LIST
command will be accumulated (using your own 'collect_incoming_data'
method) up to the terminator, and then control will be returned to
you - by calling your self.found_terminator() method.
"""
import asyncore
from collections import deque
class async_chat(asyncore.dispatcher):
"""This is an abstract class. You must derive from this class, and add
the two methods collect_incoming_data() and found_terminator()"""
# these are overridable defaults
ac_in_buffer_size = 65536
ac_out_buffer_size = 65536
# we don't want to enable the use of encoding by default, because that is a
# sign of an application bug that we don't want to pass silently
use_encoding = 0
encoding = 'latin-1'
def __init__(self, sock=None, map=None):
# for string terminator matching
self.ac_in_buffer = b''
# we use a list here rather than io.BytesIO for a few reasons...
# del lst[:] is faster than bio.truncate(0)
# lst = [] is faster than bio.truncate(0)
self.incoming = []
# we toss the use of the "simple producer" and replace it with
# a pure deque, which the original fifo was a wrapping of
self.producer_fifo = deque()
asyncore.dispatcher.__init__(self, sock, map)
def collect_incoming_data(self, data):
raise NotImplementedError("must be implemented in subclass")
def _collect_incoming_data(self, data):
self.incoming.append(data)
def _get_data(self):
d = b''.join(self.incoming)
del self.incoming[:]
return d
def found_terminator(self):
raise NotImplementedError("must be implemented in subclass")
def set_terminator(self, term):
"""Set the input delimiter.
Can be a fixed string of any length, an integer, or None.
"""
if isinstance(term, str) and self.use_encoding:
term = bytes(term, self.encoding)
elif isinstance(term, int) and term < 0:
raise ValueError('the number of received bytes must be positive')
self.terminator = term
def get_terminator(self):
return self.terminator
# grab some more data from the socket,
# throw it to the collector method,
# check for the terminator,
# if found, transition to the next state.
def handle_read(self):
try:
data = self.recv(self.ac_in_buffer_size)
except BlockingIOError:
return
except OSError as why:
self.handle_error()
return
if isinstance(data, str) and self.use_encoding:
data = bytes(str, self.encoding)
self.ac_in_buffer = self.ac_in_buffer + data
# Continue to search for self.terminator in self.ac_in_buffer,
# while calling self.collect_incoming_data. The while loop
# is necessary because we might read several data+terminator
# combos with a single recv(4096).
while self.ac_in_buffer:
lb = len(self.ac_in_buffer)
terminator = self.get_terminator()
if not terminator:
# no terminator, collect it all
self.collect_incoming_data(self.ac_in_buffer)
self.ac_in_buffer = b''
elif isinstance(terminator, int):
# numeric terminator
n = terminator
if lb < n:
self.collect_incoming_data(self.ac_in_buffer)
self.ac_in_buffer = b''
self.terminator = self.terminator - lb
else:
self.collect_incoming_data(self.ac_in_buffer[:n])
self.ac_in_buffer = self.ac_in_buffer[n:]
self.terminator = 0
self.found_terminator()
else:
# 3 cases:
# 1) end of buffer matches terminator exactly:
# collect data, transition
# 2) end of buffer matches some prefix:
# collect data to the prefix
# 3) end of buffer does not match any prefix:
# collect data
terminator_len = len(terminator)
index = self.ac_in_buffer.find(terminator)
if index != -1:
# we found the terminator
if index > 0:
# don't bother reporting the empty string
# (source of subtle bugs)
self.collect_incoming_data(self.ac_in_buffer[:index])
self.ac_in_buffer = self.ac_in_buffer[index+terminator_len:]
# This does the Right Thing if the terminator
# is changed here.
self.found_terminator()
else:
# check for a prefix of the terminator
index = find_prefix_at_end(self.ac_in_buffer, terminator)
if index:
if index != lb:
# we found a prefix, collect up to the prefix
self.collect_incoming_data(self.ac_in_buffer[:-index])
self.ac_in_buffer = self.ac_in_buffer[-index:]
break
else:
# no prefix, collect it all
self.collect_incoming_data(self.ac_in_buffer)
self.ac_in_buffer = b''
def handle_write(self):
self.initiate_send()
def handle_close(self):
self.close()
def push(self, data):
if not isinstance(data, (bytes, bytearray, memoryview)):
raise TypeError('data argument must be byte-ish (%r)',
type(data))
sabs = self.ac_out_buffer_size
if len(data) > sabs:
for i in range(0, len(data), sabs):
self.producer_fifo.append(data[i:i+sabs])
else:
self.producer_fifo.append(data)
self.initiate_send()
def push_with_producer(self, producer):
self.producer_fifo.append(producer)
self.initiate_send()
def readable(self):
"predicate for inclusion in the readable for select()"
# cannot use the old predicate, it violates the claim of the
# set_terminator method.
# return (len(self.ac_in_buffer) <= self.ac_in_buffer_size)
return 1
def writable(self):
"predicate for inclusion in the writable for select()"
return self.producer_fifo or (not self.connected)
def close_when_done(self):
"automatically close this channel once the outgoing queue is empty"
self.producer_fifo.append(None)
def initiate_send(self):
while self.producer_fifo and self.connected:
first = self.producer_fifo[0]
# handle empty string/buffer or None entry
if not first:
del self.producer_fifo[0]
if first is None:
self.handle_close()
return
# handle classic producer behavior
obs = self.ac_out_buffer_size
try:
data = first[:obs]
except TypeError:
data = first.more()
if data:
self.producer_fifo.appendleft(data)
else:
del self.producer_fifo[0]
continue
if isinstance(data, str) and self.use_encoding:
data = bytes(data, self.encoding)
# send the data
try:
num_sent = self.send(data)
except OSError:
self.handle_error()
return
if num_sent:
if num_sent < len(data) or obs < len(first):
self.producer_fifo[0] = first[num_sent:]
else:
del self.producer_fifo[0]
# we tried to send some actual data
return
def discard_buffers(self):
# Emergencies only!
self.ac_in_buffer = b''
del self.incoming[:]
self.producer_fifo.clear()
class simple_producer:
def __init__(self, data, buffer_size=512):
self.data = data
self.buffer_size = buffer_size
def more(self):
if len(self.data) > self.buffer_size:
result = self.data[:self.buffer_size]
self.data = self.data[self.buffer_size:]
return result
else:
result = self.data
self.data = b''
return result
class fifo:
def __init__(self, list=None):
import warnings
warnings.warn('fifo class will be removed in Python 3.6',
DeprecationWarning, stacklevel=2)
if not list:
self.list = deque()
else:
self.list = deque(list)
def __len__(self):
return len(self.list)
def is_empty(self):
return not self.list
def first(self):
return self.list[0]
def push(self, data):
self.list.append(data)
def pop(self):
if self.list:
return (1, self.list.popleft())
else:
return (0, None)
# Given 'haystack', see if any prefix of 'needle' is at its end. This
# assumes an exact match has already been checked. Return the number of
# characters matched.
# for example:
# f_p_a_e("qwerty\r", "\r\n") => 1
# f_p_a_e("qwertydkjf", "\r\n") => 0
# f_p_a_e("qwerty\r\n", "\r\n") => <undefined>
# this could maybe be made faster with a computed regex?
# [answer: no; circa Python-2.0, Jan 2001]
# new python: 28961/s
# old python: 18307/s
# re: 12820/s
# regex: 14035/s
def find_prefix_at_end(haystack, needle):
l = len(needle) - 1
while l and not haystack.endswith(needle[:l]):
l -= 1
return l
|