view sat/tools/trigger.py @ 2617:81b70eeb710f

quick_frontend(contact list): refactored update: update is now called with appropriate constant value (C.UPDATE_ADD, C.UPDATE_DELETE, C.UPDATE_MODIFY and so on) when a widget change visibility according to current options. Before it was linked to cache only (C.UPDATE_ADD was only called when contact was first added to cache). This make widget handling in frontends more easy. Renamed entityToShow to entityVisible, which seems to correspond better. Started reducing lines lenght to 90 chars as a test. May become the new coding style soon.
author Goffi <goffi@goffi.org>
date Sun, 24 Jun 2018 21:59:29 +0200
parents 26edcf3a30eb
children 56f94936df1e
line wrap: on
line source

#!/usr/bin/env python2
# -*- coding: utf-8 -*-

# SAT: a jabber client
# Copyright (C) 2009-2018 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 _
from sat.core.log import getLogger
log = getLogger(__name__)


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"""

    try:  # FIXME: to be removed when a better solution is found
        MIN_PRIORITY = float('-inf')
        MAX_PRIORITY = float('+inf')
    except:  # XXX: Pyjamas will bug if you specify ValueError here
        # Pyjamas uses the JS Float class
        MIN_PRIORITY = Number.NEGATIVE_INFINITY
        MAX_PRIORITY = Number.POSITIVE_INFINITY

    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 (self.MIN_PRIORITY, self.MAX_PRIORITY):
                log.warning(_(u"There is already a bound priority [%s]") % point_name)
            else:
                log.debug(_(u"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 triggers 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

    def returnPoint(self, point_name, *args, **kwargs):
        """Like point but trigger must return (continue, return_value)

        All triggers for that point must return a tuple with 2 values:
            - continue, same as for point, if False action must be finished
            - return_value: value to return ONLY IF CONTINUE IS FALSE
        @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:
                cont, ret_value = trigger(*args, **kwargs)
                if not cont:
                    return False, ret_value
            except SkipOtherTriggers:
                break
        return True, None