134 lines
4.9 KiB
Python
134 lines
4.9 KiB
Python
#!/usr/bin/env python3
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# SAT: a jabber client
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# Copyright (C) 2009-2021 Jérôme Poisson (goffi@goffi.org)
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU Affero General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU Affero General Public License for more details.
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# You should have received a copy of the GNU Affero General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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"""Misc usefull classes"""
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from libervia.backend.core.i18n import _
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from libervia.backend.core.log import getLogger
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log = getLogger(__name__)
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class TriggerException(Exception):
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pass
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class SkipOtherTriggers(Exception):
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""" Exception to raise if normal behaviour must be followed instead of following triggers list """
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pass
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class TriggerManager(object):
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"""This class manage triggers: code which interact to change the behaviour of SàT"""
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try: # FIXME: to be removed when a better solution is found
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MIN_PRIORITY = float("-inf")
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MAX_PRIORITY = float("+inf")
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except: # XXX: Pyjamas will bug if you specify ValueError here
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# Pyjamas uses the JS Float class
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MIN_PRIORITY = Number.NEGATIVE_INFINITY
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MAX_PRIORITY = Number.POSITIVE_INFINITY
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def __init__(self):
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self.__triggers = {}
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def add(self, point_name, callback, priority=0):
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"""Add a trigger to a point
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@param point_name: name of the point when the trigger should be run
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@param callback: method to call at the trigger point
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@param priority: callback will be called in priority order, biggest
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first
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"""
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if point_name not in self.__triggers:
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self.__triggers[point_name] = []
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if priority != 0 and priority in [
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trigger_tuple[0] for trigger_tuple in self.__triggers[point_name]
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]:
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if priority in (self.MIN_PRIORITY, self.MAX_PRIORITY):
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log.warning(_("There is already a bound priority [%s]") % point_name)
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else:
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log.debug(
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_("There is already a trigger with the same priority [%s]")
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% point_name
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)
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self.__triggers[point_name].append((priority, callback))
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self.__triggers[point_name].sort(
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key=lambda trigger_tuple: trigger_tuple[0], reverse=True
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)
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def remove(self, point_name, callback):
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"""Remove a trigger from a point
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@param point_name: name of the point when the trigger should be run
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@param callback: method to remove, must exists in the trigger point
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"""
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for trigger_tuple in self.__triggers[point_name]:
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if trigger_tuple[1] == callback:
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self.__triggers[point_name].remove(trigger_tuple)
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return
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raise TriggerException("Trying to remove an unexisting trigger")
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def point(self, point_name, *args, **kwargs):
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"""This put a trigger point
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All the triggers for that point will be run
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@param point_name: name of the trigger point
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@param *args: args to transmit to trigger
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@param *kwargs: kwargs to transmit to trigger
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if "triggers_no_cancel" is present, it will be popup out
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when set to True, this argument don't let triggers stop
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the workflow
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@return: True if the action must be continued, False else
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"""
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if point_name not in self.__triggers:
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return True
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can_cancel = not kwargs.pop('triggers_no_cancel', False)
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for priority, trigger in self.__triggers[point_name]:
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try:
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if not trigger(*args, **kwargs) and can_cancel:
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return False
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except SkipOtherTriggers:
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break
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return True
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def return_point(self, point_name, *args, **kwargs):
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"""Like point but trigger must return (continue, return_value)
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All triggers for that point must return a tuple with 2 values:
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- continue, same as for point, if False action must be finished
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- return_value: value to return ONLY IF CONTINUE IS FALSE
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@param point_name: name of the trigger point
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@return: True if the action must be continued, False else
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"""
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if point_name not in self.__triggers:
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return True
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for priority, trigger in self.__triggers[point_name]:
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try:
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cont, ret_value = trigger(*args, **kwargs)
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if not cont:
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return False, ret_value
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except SkipOtherTriggers:
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break
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return True, None
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