#!/usr/bin/env python
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# Copyright (C) DSTC Pty Ltd (ACN 052 372 577) 1997, 1998, 1999
# All Rights Reserved.
#
# The software contained on this media is the property of the DSTC Pty
# Ltd.  Use of this software is strictly in accordance with the
# license agreement in the accompanying LICENSE.HTML file.  If your
# distribution of this software does not contain a LICENSE.HTML file
# then you have no rights to use this software in any manner and
# should contact DSTC at the address below to determine an appropriate
# licensing arrangement.
# 
#      DSTC Pty Ltd
#      Level 7, GP South
#      Staff House Road
#      University of Queensland
#      St Lucia, 4072
#      Australia
#      Tel: +61 7 3365 4310
#      Fax: +61 7 3365 4311
#      Email: enquiries@dstc.edu.au
# 
# This software is being provided "AS IS" without warranty of any
# kind.  In no event shall DSTC Pty Ltd be liable for damage of any
# kind arising out of or in connection with the use or performance of
# this software.
#
# Project:      Fnorb
# File:         $Source: /cvsroot/fnorb/fnorb/orb/GIOPServerWorkerReactive.py,v $
# Version:      @(#)$RCSfile: GIOPServerWorkerReactive.py,v $ $Revision: 1.6 $
#
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""" GIOPServerWorkerReactive class. """


# Fnorb modules.
import CORBA, EventHandler, GIOPServerWorker, GIOPConnectionHandler, Reactor


class GIOPServerWorkerReactive(GIOPServerWorker.GIOPServerWorker,
			       EventHandler.EventHandler):
    """ GIOPServerWorkerReactive class.

    A concrete 'EventHandler' in the 'Reactor' pattern.

    This class is *not* thread safe, but since the whole point of the 'Reactor'
    pattern is to work in a single-threaded environment, I don't see this as
    much of a problem ;^)

    """
    def __init__(self, giop_version, giop_server, connection):
	""" Provide an interface to a remote object!

        'giop_version' is the GIOP version of this ORB
        'giop_server'  is the server for the connection
	'connection'   is the aconnection to the remote object.

	"""
	self.__giop_version = giop_version
	self.__giop_server  = giop_server
	self.__connection   = connection

	# Have we been closed down?
	self.__closed = 0

	# Set the connection to NON-blocking mode.
	self.__connection.blocking(0)

	# Queue of outgoing GIOP messages.
	self.__outgoing = []

	# Get a reference to the active reactor.
	self.__reactor = Reactor.Reactor_init()

	# Register our interest in read events (ie. operation requests) with
	# the Reactor.
	self.__reactor.register_handler(self, Reactor.READ)

	# Create a handler to look after the connection.
	self.__handler = GIOPConnectionHandler.GIOPConnectionHandler \
			 (self.__giop_version, self, self.__connection)
	return

    def pseudo__del__(self):
	""" Pseudo destructor to remove circular references.

	This method is called from '__shutdown' only.

	"""
	# The GIOP server holds a (circular) reference to this instance so we
	# have to explicitly clean it up.
	self.__giop_server.pseudo__del__()

	# Clean up *our* reference to *it*!
	del self.__giop_server

	# The handler also holds a (circular) reference to this instance so we
	# have to explicitly clean it up.
	self.__handler.pseudo__del__()

	# Clean up *our* reference to *it*!
	del self.__handler

	return

    #########################################################################
    # GIOPServerWorker interface.
    #########################################################################

    def send(self, message):
	""" Send a message to the 'client'.

	This method simply adds the message to the queue of outgoing messages
	and registers out interest in write events with the Reactor.

	"""
	# Add the outgoing message to the queue.
	self.__outgoing.append(message)
		
	# Register my interest in write events with the Reactor.
	self.__reactor.register_handler(self, Reactor.WRITE)

	return

    def close_connection(self):
	""" Close down the worker.

	Currently, Fnorb does not close down servers, so this is not used.

	"""
	if not self.__closed:
	    # Don't accept any more operation requests.
	    self.__reactor.unregister_handler(self, Reactor.READ)

	    # Send all outstanding messages.
	    while len(self.__outgoing) > 0:
		self.__reactor.do_one_event()

	    # Close down the worker.
	    self.__close()

	return

    #########################################################################
    # EventHandler interface.
    #########################################################################

    def handle_event(self, mask):
	""" Callback method to handle all events except close events. """

	# Read event.
	if mask & Reactor.READ:
	    try:
		self.__handler.recv()

	    except CORBA.SystemException:
		self.handle_close()

	# Write event.
	elif mask & Reactor.WRITE:
	    try:
		self.__handler.send(self.__outgoing[0])

	    except CORBA.SystemException:
		self.handle_close()

	# Exception event.
	elif mask & Reactor.EXCEPTION:
	    self.handle_close()

	return

    def handle_close(self):
	""" Callback method to handle close events. """

	# Close down the worker.
	self.__close()

	return

    def handle(self):
	""" Return my underlying I/O handle.

	In this case, my I/O handle is the file descriptor of my socket. 

	"""
	return self.__connection.handle()

    #########################################################################
    # GIOPConnectionHandlerListener interface.
    #########################################################################

    def message_received(self, message):
	""" Called when a complete GIOP message has been received. """

	# Pass the message up to the GIOP server.
	self.__giop_server.process_giop_message(message)

	return

    def message_sent(self):
	""" Called when a complete GIOP message has been sent. """

	# Remove the message from the outgoing queue.
	del self.__outgoing[0]

	# If there are no other messages left to send then tell the Reactor
	# that I am no longer interested in write events.
	if len(self.__outgoing) == 0:
	    self.__reactor.unregister_handler(self, Reactor.WRITE)

	return

    #########################################################################
    # Private interface.
    #########################################################################

    def __close(self):
	""" Close down the worker. """

	if not self.__closed:
	    # Withdraw all of my Reactor registrations.
	    self.__reactor.unregister_handler(self, Reactor.ALL)

	    # Set the connection to blocking mode.
	    self.__connection.blocking(1)

	    # Close our connection.
	    self.__connection.disconnect()

	    # All done!
	    self.__closed = 1

	    # Remove circular references.
	    self.pseudo__del__()

	return

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