libervia-backend/src/tools/misc.py
2014-02-04 18:32:49 +01:00

89 lines
3.3 KiB
Python

#!/usr/bin/python
# -*- coding: utf-8 -*-
# SAT: a jabber client
# Copyright (C) 2009, 2010, 2011, 2012, 2013, 2014 Jérôme Poisson (goffi@goffi.org)
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Affero General Public License for more details.
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
"""Misc usefull classes"""
from sat.core.i18n import _
import sys
from logging import debug, warning
class TriggerException(Exception):
pass
class SkipOtherTriggers(Exception):
""" Exception to raise if normal behaviour must be followed instead of
following triggers list """
pass
class TriggerManager(object):
"""This class manage triggers: code which interact to change the behaviour
of SàT"""
MIN_PRIORITY = float('-inf')
MAX_PRIORITY = float('+inf')
def __init__(self):
self.__triggers = {}
def add(self, point_name, callback, priority=0):
"""Add a trigger to a point
@param point_name: name of the point when the trigger should be run
@param callback: method to call at the trigger point
@param priority: callback will be called in priority order, biggest
first
"""
if point_name not in self.__triggers:
self.__triggers[point_name] = []
if priority != 0 and priority in [trigger_tuple[0] for trigger_tuple in self.__triggers[point_name]]:
if priority in (MIN_PRIORITY, MAX_PRIORITY):
warning(_("There is already a bound priority [%s]") % point_name)
else:
debug(_("There is already a trigger with the same priority [%s]") % point_name)
self.__triggers[point_name].append((priority, callback))
self.__triggers[point_name].sort(key=lambda trigger_tuple:
trigger_tuple[0], reverse=True)
def remove(self, point_name, callback):
"""Remove a trigger from a point
@param point_name: name of the point when the trigger should be run
@param callback: method to remove, must exists in the trigger point"""
for trigger_tuple in self.__triggers[point_name]:
if trigger_tuple[1] == callback:
self.__triggers[point_name].remove(trigger_tuple)
return
raise TriggerException("Trying to remove an unexisting trigger")
def point(self, point_name, *args, **kwargs):
"""This put a trigger point
All the trigger for that point will be run
@param point_name: name of the trigger point
@return: True if the action must be continued, False else"""
if point_name not in self.__triggers:
return True
for priority,trigger in self.__triggers[point_name]:
try:
if not trigger(*args, **kwargs):
return False
except SkipOtherTriggers:
break
return True