--- rest25/library/asynchat.rst	2008-12-19 16:58:07.000000000 +0900
+++ rest262/library/asynchat.rst	2009-04-05 05:02:09.000000000 +0900
@@ -1,263 +1,294 @@
 
 :mod:`asynchat` --- Asynchronous socket command/response handler
 ================================================================
 
 .. module:: asynchat
    :synopsis: Support for asynchronous command/response protocols.
 .. moduleauthor:: Sam Rushing <rushing@nightmare.com>
 .. sectionauthor:: Steve Holden <sholden@holdenweb.com>
 
 
 This module builds on the :mod:`asyncore` infrastructure, simplifying
-asynchronous clients and servers and making it easier to handle protocols whose
-elements are terminated by arbitrary strings, or are of variable length.
+asynchronous clients and servers and making it easier to handle protocols
+whose elements are terminated by arbitrary strings, or are of variable length.
 :mod:`asynchat` defines the abstract class :class:`async_chat` that you
 subclass, providing implementations of the :meth:`collect_incoming_data` and
 :meth:`found_terminator` methods. It uses the same asynchronous loop as
-:mod:`asyncore`, and the two types of channel, :class:`asyncore.dispatcher` and
+:mod:`asyncore`, and the two types of channel, :class:`asyncore.dispatcher`
-:class:`asynchat.async_chat`, can freely be mixed in the channel map. Typically
+and :class:`asynchat.async_chat`, can freely be mixed in the channel map.
-an :class:`asyncore.dispatcher` server channel generates new
+Typically an :class:`asyncore.dispatcher` server channel generates new
-:class:`asynchat.async_chat` channel objects as it receives incoming connection
+:class:`asynchat.async_chat` channel objects as it receives incoming
-requests.
+connection requests.
 
 
 .. class:: async_chat()
 
    This class is an abstract subclass of :class:`asyncore.dispatcher`. To make
    practical use of the code you must subclass :class:`async_chat`, providing
-   meaningful :meth:`collect_incoming_data` and :meth:`found_terminator` methods.
+   meaningful :meth:`collect_incoming_data` and :meth:`found_terminator`
+   methods.
    The :class:`asyncore.dispatcher` methods can be used, although not all make
    sense in a message/response context.
 
-   Like :class:`asyncore.dispatcher`, :class:`async_chat` defines a set of events
-   that are generated by an analysis of socket conditions after a :cfunc:`select`
-   call. Once the polling loop has been started the :class:`async_chat` object's
-   methods are called by the event-processing framework with no action on the part
-   of the programmer.
+   Like :class:`asyncore.dispatcher`, :class:`async_chat` defines a set of
+   events that are generated by an analysis of socket conditions after a
+   :cfunc:`select` call. Once the polling loop has been started the
+   :class:`async_chat` object's methods are called by the event-processing
+   framework with no action on the part of the programmer.
+
+   Two class attributes can be modified, to improve performance, or possibly
+   even to conserve memory.
+
+
+   .. data:: ac_in_buffer_size
+
+      The asynchronous input buffer size (default ``4096``).
+
+
+   .. data:: ac_out_buffer_size
+
+      The asynchronous output buffer size (default ``4096``).
+
-
-   Unlike :class:`asyncore.dispatcher`, :class:`async_chat` allows you to define a
-   first-in-first-out queue (fifo) of *producers*. A producer need have only one
-   method, :meth:`more`, which should return data to be transmitted on the channel.
+   Unlike :class:`asyncore.dispatcher`, :class:`async_chat` allows you to
+   define a first-in-first-out queue (fifo) of *producers*. A producer need
+   have only one method, :meth:`more`, which should return data to be
+   transmitted on the channel.
    The producer indicates exhaustion (*i.e.* that it contains no more data) by
    having its :meth:`more` method return the empty string. At this point the
-   :class:`async_chat` object removes the producer from the fifo and starts using
-   the next producer, if any. When the producer fifo is empty the
+   :class:`async_chat` object removes the producer from the fifo and starts
+   using the next producer, if any. When the producer fifo is empty the
    :meth:`handle_write` method does nothing. You use the channel object's
-   :meth:`set_terminator` method to describe how to recognize the end of, or an
-   important breakpoint in, an incoming transmission from the remote endpoint.
+   :meth:`set_terminator` method to describe how to recognize the end of, or
+   an important breakpoint in, an incoming transmission from the remote
+   endpoint.
 
    To build a functioning :class:`async_chat` subclass your  input methods
-   :meth:`collect_incoming_data` and :meth:`found_terminator` must handle the data
-   that the channel receives asynchronously. The methods are described below.
+   :meth:`collect_incoming_data` and :meth:`found_terminator` must handle the
+   data that the channel receives asynchronously. The methods are described
+   below.
 
 
 .. method:: async_chat.close_when_done()
 
-   Pushes a ``None`` on to the producer fifo. When this producer is popped off the
-   fifo it causes the channel to be closed.
+   Pushes a ``None`` on to the producer fifo. When this producer is popped off
+   the fifo it causes the channel to be closed.
 
 
 .. method:: async_chat.collect_incoming_data(data)
 
-   Called with *data* holding an arbitrary amount of received data. The default
-   method, which must be overridden, raises a :exc:`NotImplementedError` exception.
+   Called with *data* holding an arbitrary amount of received data.  The
+   default method, which must be overridden, raises a
+   :exc:`NotImplementedError` exception.
+
+
+.. method:: async_chat._collect_incoming_data(data)
+
+   Sample implementation of a data collection rutine to be used in conjunction
+   with :meth:`_get_data` in a user-specified :meth:`found_terminator`.
 
 
 .. method:: async_chat.discard_buffers()
 
-   In emergencies this method will discard any data held in the input and/or output
-   buffers and the producer fifo.
+   In emergencies this method will discard any data held in the input and/or
+   output buffers and the producer fifo.
 
 
 .. method:: async_chat.found_terminator()
 
-   Called when the incoming data stream  matches the termination condition set by
-   :meth:`set_terminator`. The default method, which must be overridden, raises a
-   :exc:`NotImplementedError` exception. The buffered input data should be
-   available via an instance attribute.
+   Called when the incoming data stream  matches the termination condition set
+   by :meth:`set_terminator`. The default method, which must be overridden,
+   raises a :exc:`NotImplementedError` exception. The buffered input data
+   should be available via an instance attribute.
+
+
+.. method:: async_chat._get_data()
+
+   Will return and clear the data received with the sample
+   :meth:`_collect_incoming_data` implementation.
 
 
 .. method:: async_chat.get_terminator()
 
    Returns the current terminator for the channel.
 
 
 .. method:: async_chat.handle_close()
 
    Called when the channel is closed. The default method silently closes the
    channel's socket.
 
 
 .. method:: async_chat.handle_read()
 
-   Called when a read event fires on the channel's socket in the asynchronous loop.
-   The default method checks for the termination condition established by
-   :meth:`set_terminator`, which can be either the appearance of a particular
-   string in the input stream or the receipt of a particular number of characters.
-   When the terminator is found, :meth:`handle_read` calls the
-   :meth:`found_terminator` method after calling :meth:`collect_incoming_data` with
-   any data preceding the terminating condition.
+   Called when a read event fires on the channel's socket in the asynchronous
+   loop.  The default method checks for the termination condition established
+   by :meth:`set_terminator`, which can be either the appearance of a
+   particular string in the input stream or the receipt of a particular number
+   of characters.  When the terminator is found, :meth:`handle_read` calls the
+   :meth:`found_terminator` method after calling :meth:`collect_incoming_data`
+   with any data preceding the terminating condition.
 
 
 .. method:: async_chat.handle_write()
 
-   Called when the application may write data to the channel.   The default method
-   calls the :meth:`initiate_send` method, which in turn will call
-   :meth:`refill_buffer` to collect data from the producer fifo associated with the
-   channel.
+   Called when the application may write data to the channel.   The default
+   method calls the :meth:`initiate_send` method, which in turn will call
+   :meth:`refill_buffer` to collect data from the producer fifo associated
+   with the channel.
 
 
 .. method:: async_chat.push(data)
 
-   Creates a :class:`simple_producer` object (*see below*) containing the data and
-   pushes it on to the channel's ``producer_fifo`` to ensure its transmission. This
-   is all you need to do to have the channel write the data out to the network,
-   although it is possible to use your own producers in more complex schemes to
-   implement encryption and chunking, for example.
+   Creates a :class:`simple_producer` object (*see below*) containing the data
+   and pushes it on to the channel's ``producer_fifo`` to ensure its
+   transmission.  This is all you need to do to have the channel write the
+   data out to the network, although it is possible to use your own producers
+   in more complex schemes to implement encryption and chunking, for example.
 
 
 .. method:: async_chat.push_with_producer(producer)
 
-   Takes a producer object and adds it to the producer fifo associated with the
-   channel. When all currently-pushed producers have been exhausted the channel
-   will consume this producer's data by calling its :meth:`more` method and send
-   the data to the remote endpoint.
+   Takes a producer object and adds it to the producer fifo associated with
+   the channel.  When all currently-pushed producers have been exhausted the
+   channel will consume this producer's data by calling its :meth:`more`
+   method and send the data to the remote endpoint.
 
 
 .. method:: async_chat.readable()
 
-   Should return ``True`` for the channel to be included in the set of channels
-   tested by the :cfunc:`select` loop for readability.
+   Should return ``True`` for the channel to be included in the set of
+   channels tested by the :cfunc:`select` loop for readability.
 
 
 .. method:: async_chat.refill_buffer()
 
-   Refills the output buffer by calling the :meth:`more` method of the producer at
-   the head of the fifo. If it is exhausted then the producer is popped off the
-   fifo and the next producer is activated. If the current producer is, or becomes,
-   ``None`` then the channel is closed.
+   Refills the output buffer by calling the :meth:`more` method of the
+   producer at the head of the fifo.  If it is exhausted then the producer is
+   popped off the fifo and the next producer is activated.  If the current
+   producer is, or becomes, ``None`` then the channel is closed.
 
 
 .. method:: async_chat.set_terminator(term)
 
-   Sets the terminating condition to be recognised on the channel. ``term`` may be
-   any of three types of value, corresponding to three different ways to handle
-   incoming protocol data.
+   Sets the terminating condition to be recognized on the channel.  ``term``
+   may be any of three types of value, corresponding to three different ways
+   to handle incoming protocol data.
 
    +-----------+---------------------------------------------+
    | term      | Description                                 |
    +===========+=============================================+
    | *string*  | Will call :meth:`found_terminator` when the |
    |           | string is found in the input stream         |
    +-----------+---------------------------------------------+
    | *integer* | Will call :meth:`found_terminator` when the |
    |           | indicated number of characters have been    |
    |           | received                                    |
    +-----------+---------------------------------------------+
    | ``None``  | The channel continues to collect data       |
    |           | forever                                     |
    +-----------+---------------------------------------------+
 
-   Note that any data following the terminator will be available for reading by the
-   channel after :meth:`found_terminator` is called.
+   Note that any data following the terminator will be available for reading
+   by the channel after :meth:`found_terminator` is called.
 
 
 .. method:: async_chat.writable()
 
    Should return ``True`` as long as items remain on the producer fifo, or the
    channel is connected and the channel's output buffer is non-empty.
 
 
 asynchat - Auxiliary Classes and Functions
 ------------------------------------------
 
 
 .. class:: simple_producer(data[, buffer_size=512])
 
-   A :class:`simple_producer` takes a chunk of data and an optional buffer size.
-   Repeated calls to its :meth:`more` method yield successive chunks of the data no
-   larger than *buffer_size*.
+   A :class:`simple_producer` takes a chunk of data and an optional buffer
+   size.  Repeated calls to its :meth:`more` method yield successive chunks of
+   the data no larger than *buffer_size*.
 
 
-.. method:: simple_producer.more()
+   .. method:: more()
 
-   Produces the next chunk of information from the producer, or returns the empty
-   string.
+      Produces the next chunk of information from the producer, or returns the
+      empty string.
 
 
 .. class:: fifo([list=None])
 
-   Each channel maintains a :class:`fifo` holding data which has been pushed by the
-   application but not yet popped for writing to the channel. A :class:`fifo` is a
-   list used to hold data and/or producers until they are required. If the *list*
-   argument is provided then it should contain producers or data items to be
-   written to the channel.
+   Each channel maintains a :class:`fifo` holding data which has been pushed
+   by the application but not yet popped for writing to the channel.  A
+   :class:`fifo` is a list used to hold data and/or producers until they are
+   required.  If the *list* argument is provided then it should contain
+   producers or data items to be written to the channel.
 
 
-.. method:: fifo.is_empty()
+   .. method:: is_empty()
 
-   Returns ``True`` iff the fifo is empty.
+      Returns ``True`` if and only if the fifo is empty.
 
 
-.. method:: fifo.first()
+   .. method:: first()
 
-   Returns the least-recently :meth:`push`\ ed item from the fifo.
+      Returns the least-recently :meth:`push`\ ed item from the fifo.
 
 
-.. method:: fifo.push(data)
+   .. method:: push(data)
 
-   Adds the given data (which may be a string or a producer object) to the producer
-   fifo.
+      Adds the given data (which may be a string or a producer object) to the
+      producer fifo.
 
 
-.. method:: fifo.pop()
+   .. method:: pop()
 
-   If the fifo is not empty, returns ``True, first()``, deleting the popped item.
-   Returns ``False, None`` for an empty fifo.
+      If the fifo is not empty, returns ``True, first()``, deleting the popped
+      item.  Returns ``False, None`` for an empty fifo.
 
 The :mod:`asynchat` module also defines one utility function, which may be of
 use in network and textual analysis operations.
 
 
 .. function:: find_prefix_at_end(haystack, needle)
 
-   Returns ``True`` if string *haystack* ends with any non-empty prefix of string
-   *needle*.
+   Returns ``True`` if string *haystack* ends with any non-empty prefix of
+   string *needle*.
 
 
 .. _asynchat-example:
 
 asynchat Example
 ----------------
 
 The following partial example shows how HTTP requests can be read with
-:class:`async_chat`. A web server might create an :class:`http_request_handler`
-object for each incoming client connection. Notice that initially the channel
-terminator is set to match the blank line at the end of the HTTP headers, and a
-flag indicates that the headers are being read.
-
-Once the headers have been read, if the request is of type POST (indicating that
-further data are present in the input stream) then the ``Content-Length:``
-header is used to set a numeric terminator to read the right amount of data from
-the channel.
+:class:`async_chat`.  A web server might create an
+:class:`http_request_handler` object for each incoming client connection.
+Notice that initially the channel terminator is set to match the blank line at
+the end of the HTTP headers, and a flag indicates that the headers are being
+read.
+
+Once the headers have been read, if the request is of type POST (indicating
+that further data are present in the input stream) then the
+``Content-Length:`` header is used to set a numeric terminator to read the
+right amount of data from the channel.
 
 The :meth:`handle_request` method is called once all relevant input has been
-marshalled, after setting the channel terminator to ``None`` to ensure that any
-extraneous data sent by the web client are ignored. ::
+marshalled, after setting the channel terminator to ``None`` to ensure that
+any extraneous data sent by the web client are ignored. ::
 
    class http_request_handler(asynchat.async_chat):
 
-       def __init__(self, conn, addr, sessions, log):
-           asynchat.async_chat.__init__(self, conn=conn)
+       def __init__(self, sock, addr, sessions, log):
+           asynchat.async_chat.__init__(self, sock=sock)
            self.addr = addr
            self.sessions = sessions
            self.ibuffer = []
            self.obuffer = ""
            self.set_terminator("\r\n\r\n")
            self.reading_headers = True
            self.handling = False
            self.cgi_data = None
            self.log = log
 
        def collect_incoming_data(self, data):
            """Buffer the data"""
@@ -272,13 +303,12 @@
                    clen = self.headers.getheader("content-length")
                    self.set_terminator(int(clen))
                else:
                    self.handling = True
                    self.set_terminator(None)
                    self.handle_request()
            elif not self.handling:
                self.set_terminator(None) # browsers sometimes over-send
                self.cgi_data = parse(self.headers, "".join(self.ibuffer))
                self.handling = True
                self.ibuffer = []
                self.handle_request()
-
