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4b8c6eaf8b
*this* set of patches is Ka-Ping's final sweep: The attached patches update the standard library so that all modules have docstrings beginning with one-line summaries. A new docstring was added to formatter. The docstring for os.py was updated to mention nt, os2, ce in addition to posix, dos, mac.
316 lines
9.2 KiB
Python
316 lines
9.2 KiB
Python
# -*- Mode: Python; tab-width: 4 -*-
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# Id: asynchat.py,v 2.23 1999/05/01 04:49:24 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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"""A class supporting chat-style (command/response) protocols.
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This class adds support for 'chat' style protocols - where one side
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sends a 'command', and the other sends a response (examples would be
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the common internet protocols - smtp, nntp, ftp, etc..).
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The handle_read() method looks at the input stream for the current
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'terminator' (usually '\r\n' for single-line responses, '\r\n.\r\n'
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for multi-line output), calling self.found_terminator() on its
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receipt.
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for example:
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Say you build an async nntp client using this class. At the start
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of the connection, you'll have self.terminator set to '\r\n', in
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order to process the single-line greeting. Just before issuing a
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'LIST' command you'll set it to '\r\n.\r\n'. The output of the LIST
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command will be accumulated (using your own 'collect_incoming_data'
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method) up to the terminator, and then control will be returned to
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you - by calling your self.found_terminator() method.
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"""
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import socket
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import asyncore
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import string
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class async_chat (asyncore.dispatcher):
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"""This is an abstract class. You must derive from this class, and add
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the two methods collect_incoming_data() and found_terminator()"""
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# these are overridable defaults
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ac_in_buffer_size = 4096
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ac_out_buffer_size = 4096
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def __init__ (self, conn=None):
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self.ac_in_buffer = ''
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self.ac_out_buffer = ''
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self.producer_fifo = fifo()
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asyncore.dispatcher.__init__ (self, conn)
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def set_terminator (self, term):
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"Set the input delimiter. Can be a fixed string of any length, an integer, or None"
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self.terminator = term
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def get_terminator (self):
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return self.terminator
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# grab some more data from the socket,
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# throw it to the collector method,
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# check for the terminator,
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# if found, transition to the next state.
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def handle_read (self):
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try:
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data = self.recv (self.ac_in_buffer_size)
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except socket.error, why:
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self.handle_error()
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return
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self.ac_in_buffer = self.ac_in_buffer + data
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# Continue to search for self.terminator in self.ac_in_buffer,
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# while calling self.collect_incoming_data. The while loop
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# is necessary because we might read several data+terminator
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# combos with a single recv(1024).
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while self.ac_in_buffer:
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lb = len(self.ac_in_buffer)
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terminator = self.get_terminator()
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if terminator is None:
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# no terminator, collect it all
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self.collect_incoming_data (self.ac_in_buffer)
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self.ac_in_buffer = ''
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elif type(terminator) == type(0):
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# numeric terminator
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n = terminator
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if lb < n:
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self.collect_incoming_data (self.ac_in_buffer)
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self.ac_in_buffer = ''
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self.terminator = self.terminator - lb
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else:
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self.collect_incoming_data (self.ac_in_buffer[:n])
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self.ac_in_buffer = self.ac_in_buffer[n:]
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self.terminator = 0
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self.found_terminator()
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else:
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# 3 cases:
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# 1) end of buffer matches terminator exactly:
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# collect data, transition
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# 2) end of buffer matches some prefix:
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# collect data to the prefix
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# 3) end of buffer does not match any prefix:
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# collect data
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terminator_len = len(terminator)
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index = string.find (self.ac_in_buffer, terminator)
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if index != -1:
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# we found the terminator
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self.collect_incoming_data (self.ac_in_buffer[:index])
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self.ac_in_buffer = self.ac_in_buffer[index+terminator_len:]
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# This does the Right Thing if the terminator is changed here.
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self.found_terminator()
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else:
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# check for a prefix of the terminator
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index = find_prefix_at_end (self.ac_in_buffer, terminator)
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if index:
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if index != lb:
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# we found a prefix, collect up to the prefix
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self.collect_incoming_data (self.ac_in_buffer[:-index])
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self.ac_in_buffer = self.ac_in_buffer[-index:]
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break
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else:
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# no prefix, collect it all
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self.collect_incoming_data (self.ac_in_buffer)
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self.ac_in_buffer = ''
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def handle_write (self):
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self.initiate_send ()
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def handle_close (self):
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self.close()
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def push (self, data):
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self.producer_fifo.push (simple_producer (data))
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self.initiate_send()
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def push_with_producer (self, producer):
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self.producer_fifo.push (producer)
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self.initiate_send()
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def readable (self):
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"predicate for inclusion in the readable for select()"
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return (len(self.ac_in_buffer) <= self.ac_in_buffer_size)
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def writable (self):
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"predicate for inclusion in the writable for select()"
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# return len(self.ac_out_buffer) or len(self.producer_fifo) or (not self.connected)
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# this is about twice as fast, though not as clear.
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return not (
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(self.ac_out_buffer is '') and
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self.producer_fifo.is_empty() and
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self.connected
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)
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def close_when_done (self):
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"automatically close this channel once the outgoing queue is empty"
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self.producer_fifo.push (None)
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# refill the outgoing buffer by calling the more() method
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# of the first producer in the queue
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def refill_buffer (self):
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_string_type = type('')
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while 1:
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if len(self.producer_fifo):
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p = self.producer_fifo.first()
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# a 'None' in the producer fifo is a sentinel,
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# telling us to close the channel.
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if p is None:
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if not self.ac_out_buffer:
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self.producer_fifo.pop()
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self.close()
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return
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elif type(p) is _string_type:
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self.producer_fifo.pop()
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self.ac_out_buffer = self.ac_out_buffer + p
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return
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data = p.more()
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if data:
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self.ac_out_buffer = self.ac_out_buffer + data
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return
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else:
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self.producer_fifo.pop()
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else:
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return
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def initiate_send (self):
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obs = self.ac_out_buffer_size
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# try to refill the buffer
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if (len (self.ac_out_buffer) < obs):
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self.refill_buffer()
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if self.ac_out_buffer and self.connected:
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# try to send the buffer
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try:
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num_sent = self.send (self.ac_out_buffer[:obs])
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if num_sent:
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self.ac_out_buffer = self.ac_out_buffer[num_sent:]
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except socket.error, why:
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self.handle_error()
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return
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def discard_buffers (self):
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# Emergencies only!
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self.ac_in_buffer = ''
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self.ac_out_buffer == ''
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while self.producer_fifo:
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self.producer_fifo.pop()
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class simple_producer:
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def __init__ (self, data, buffer_size=512):
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self.data = data
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self.buffer_size = buffer_size
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def more (self):
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if len (self.data) > self.buffer_size:
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result = self.data[:self.buffer_size]
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self.data = self.data[self.buffer_size:]
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return result
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else:
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result = self.data
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self.data = ''
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return result
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class fifo:
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def __init__ (self, list=None):
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if not list:
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self.list = []
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else:
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self.list = list
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def __len__ (self):
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return len(self.list)
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def is_empty (self):
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return self.list == []
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def first (self):
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return self.list[0]
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def push (self, data):
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self.list.append (data)
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def pop (self):
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if self.list:
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result = self.list[0]
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del self.list[0]
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return (1, result)
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else:
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return (0, None)
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# Given 'haystack', see if any prefix of 'needle' is at its end. This
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# assumes an exact match has already been checked. Return the number of
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# characters matched.
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# for example:
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# f_p_a_e ("qwerty\r", "\r\n") => 1
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# f_p_a_e ("qwerty\r\n", "\r\n") => 2
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# f_p_a_e ("qwertydkjf", "\r\n") => 0
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# this could maybe be made faster with a computed regex?
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##def find_prefix_at_end (haystack, needle):
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## nl = len(needle)
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## result = 0
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## for i in range (1,nl):
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## if haystack[-(nl-i):] == needle[:(nl-i)]:
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## result = nl-i
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## break
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## return result
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# yes, this is about twice as fast, but still seems
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# to be neglible CPU. The previous could do about 290
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# searches/sec. the new one about 555/sec.
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import regex
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prefix_cache = {}
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def prefix_regex (needle):
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if prefix_cache.has_key (needle):
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return prefix_cache[needle]
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else:
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reg = needle[-1]
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for i in range(1,len(needle)):
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reg = '%c\(%s\)?' % (needle[-(i+1)], reg)
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reg = regex.compile (reg+'$')
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prefix_cache[needle] = reg, len(needle)
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return reg, len(needle)
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def find_prefix_at_end (haystack, needle):
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reg, length = prefix_regex (needle)
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lh = len(haystack)
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result = reg.search (haystack, max(0,lh-length))
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if result >= 0:
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return (lh - result)
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else:
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return 0
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