connection.py

# coding: UTF-8
"""
Copyright (c) 2009 Marian Tietz
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:

1. Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
   notice, this list of conditions and the following disclaimer in the
   documentation and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
SUCH DAMAGE.
"""

import os
import dbus
import urwid

from gettext import gettext as _
from urwid import MetaSignals
from types import NoneType

from typecheck import types


required_version = (1, 1, 0)


class SushiWrapper(object):

	__metaclass__ = MetaSignals
	signals = ["error","connected","disconnected"]

	@types (sushi_interface = (dbus.Interface, NoneType))
	def __init__(self, sushi_interface):
		self._set_interface(sushi_interface)

	@types (connected = bool)
	def _set_connected(self, connected):
		self._connected = connected

		if connected:
			self._urwid_emit("connected", self)
		else:
			self._urwid_emit("disconnected", self)

	@types (interface = (dbus.Interface, NoneType))
	def _set_interface(self, interface):
		self._sushi = interface
		self._set_connected(interface != None)

	def _urwid_emit(self, signal, *args, **kwargs):
		urwid.emit_signal(self, signal, *args, **kwargs)

	def __getattr__(self, attr):
		def dummy(*args, **kwargs):
			self._urwid_emit("error", _("tekka could not contact maki."),
				_("There's no connection to maki, so the recent "
				"action was not performed. Try to reconnect to "
				"maki to solve this problem."))

		if attr[0] == "_" or attr == "connected":
			# return my attributes
			return object.__getattr__(self, attr)
		else:
			if not self._sushi:
				return dummy
			else:
				if attr in dir(self._sushi):
					# return local from Interface
					return eval("self._sushi.%s" % attr)
				else:
					# return dbus proxy method
					return self._sushi.__getattr__(attr)
		raise AttributeError(attr)

	connected = property(lambda s: s._connected, _set_connected)


sushi = SushiWrapper(None)

_shutdown_handler = None


def get_bus():
	bus_address = os.getenv("SUSHI_REMOTE_BUS_ADDRESS")

	from dbus.mainloop.glib import DBusGMainLoop
	loop=DBusGMainLoop(set_as_default=True)

	if bus_address:
		bus = dbus.connection.Connection(bus_address,mainloop=loop)
	else:
		bus = dbus.SessionBus(mainloop=loop)
	return bus


def connect():
	"""
		Connect to maki over DBus.
		Returns True if the connection attempt
		was succesful.
	"""
	global sushi, _shutdown_handler

	bus = get_bus()

	proxy = None

	try:
		proxy = bus.get_object("de.ikkoku.sushi", "/de/ikkoku/sushi")
	except dbus.exceptions.DBusException, e:
		sushi._urwid_emit(
			"error",
			_("Error while connecting to maki."),
			_("Error: %s" % (e)))

	if not proxy:
		return False

	sushi._set_interface(dbus.Interface(proxy, "de.ikkoku.sushi"))

	version = tuple([int(v) for v in sushi.version()])

	if not version or version < required_version:
		sushi._set_interface(None)
		return False

	_shutdown_handler = sushi.connect_to_signal (
		"shutdown", lambda time: disconnect())

	return True


def disconnect():
	global sushi, __connected, _shutdown_handler

	sushi._set_interface(None)

	_shutdown_handler.remove()


def parse_from (from_str):
	h = from_str.split("!", 2)

	if len(h) < 2:
		return (h[0],"","")

	t = h[1].split("@", 2)

	if len(t) < 2:
		return (h[0],"","")

	return (h[0], t[0], t[1])