shinken/autoslots.py

   1 #!/usr/bin/env python
   2 #
   3 # Copyright (C) 2009-2010 :
   4 #    Gabes Jean, naparuba@gmail.com
   5 #    Gerhard Lausser, Gerhard.Lausser@consol.de
   6 #    Gregory Starck, g.starck@gmail.com
   7 #    Hartmut Goebel, h.goebel@goebel-consult.de
   8 #
   9 # This file is part of Shinken.
  10 #
  11 # Shinken is free software: you can redistribute it and/or modify
  12 # it under the terms of the GNU Affero General Public License as published by
  13 # the Free Software Foundation, either version 3 of the License, or
  14 # (at your option) any later version.
  15 #
  16 # Shinken is distributed in the hope that it will be useful,
  17 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 # GNU Affero General Public License for more details.
  20 #
  21 # You should have received a copy of the GNU Affero General Public License
  22 # along with Shinken.  If not, see <http://www.gnu.org/licenses/>.
  23
  24 """The AutoSlots Class is a MetaClass : it manage how other classes
  25  are created (Classes, not instances of theses classes).
  26  Here it's role is to create the __slots__ list of the class with
  27  all properties of Class.properties and Class.running_properties
  28  so we do not have to add manually all properties to the __slots__
  29  list when we add a new entry"""
  30
  31 class AutoSlots(type):
  32     # new is call when we create a new Class
  33     # that have metaclass = AutoSlots
  34     # CLS is AutoSlots
  35     # name is s tring of the Class (like Service)
  36     # bases are the Classes of which Class inherits (like SchedulingItem)
  37     # dct is the new Class dict (like all method of Service)
  38     # Some properties name are not alowed in __slots__ like 2d_coords of
  39     # Host, so we must tag them in properties with no_slots
  40     def __new__(cls, name, bases, dct):
  41         # Thanks to Bertrand Mathieu to the set idea
  42         slots = dct.get('__slots__', set())
  43         # Now get properties from properties and running_properties
  44         if 'properties' in dct:
  45             props = dct['properties']
  46             slots.update((p for p in props
  47                           if not props[p].no_slots))
  48         if 'running_properties' in dct:
  49             props = dct['running_properties']
  50             slots.update((p for p in props
  51                           if not props[p].no_slots))
  52         dct['__slots__'] = tuple(slots)
  53         return type.__new__(cls, name, bases, dct)