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