"""
Associate a physical transport layer with a protocol.

Author: Georg Hopp <ghopp@spamtitan.com>
"""

from EndPoint import CommunicationEndPoint

from Transport import Transport

class Connection(CommunicationEndPoint):
    _EVENTS = { 'new_con' : 0x01 }

    def __init__(self, transport, protocol, read_chunk_size=8192):
        super(Connection, self).__init__(transport, protocol, read_chunk_size)
        self._current_msg     = None
        self._read_buffer     = ''
        self._write_buffer    = ''

    def hasPendingData(self):
        return '' != self._write_buffer

    def __iter__(self):
        return self

    def next(self):
        """
        iterate through all available data and return all messages that can
        be created from it. This is destructive for data.
        """
        if not self._current_msg or self._current_msg.ready():
            self._current_msg = self._protocol.createMessage(
                self.getTransport().remote)

        end = self._protocol.getParser().parse(
            self._current_msg, self._read_buffer)

        if 0 == end:
            raise StopIteration

        self._read_buffer = self._read_buffer[end:]
        if not self._current_msg.ready():
            raise StopIteration

        return self._current_msg

    def compose(self, message):
        try:
            self._write_buffer += self._protocol.getComposer().compose(message)
        except Exception:
            return False

        return True

    def appendReadData(self, data_remote):
        self._read_buffer += data_remote[0]

    def nextWriteData(self):
        buf = self._write_buffer
        self._write_buffer = ''
        return (buf, None)

    def appendWriteData(self, data_remote):
        self._write_buffer += data_remote[0]

# vim: set ft=python et ts=8 sw=4 sts=4: