Overlord/plugin_pattern.py

   1 # This file is part of the Omaha Board-Game GUI.
   2 # Copyright (C) 2009-2015  Yann Dirson
   3 #
   4 # This library is free software; you can redistribute it and/or
   5 # modify it under the terms of the GNU Lesser General Public
   6 # License as published by the Free Software Foundation,
   7 # version 2.1 of the License.
   8 #
   9 # This library is distributed in the hope that it will be useful,
  10 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12 # Lesser General Public License for more details.
  13 #
  14 # You should have received a copy of the GNU Lesser General Public
  15 # License along with this library; if not, write to the Free Software
  16 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  17
  18 __all__ = [ 'PluginPattern' ]
  19
  20 from .misc import class_fullname
  21
  22 import logging
  23 logger = logging.getLogger('Overlord.plugin_pattern')
  24
  25 class PluginPattern(object):
  26     def match_distance(self, plugin):
  27         raise NotImplementedError()
  28
  29 class AnyPluginPattern(PluginPattern):
  30     def match_distance(self, plugin):
  31         return 0
  32 Any = AnyPluginPattern()
  33
  34 class Or(PluginPattern):
  35     def __init__(self, *patterns):
  36         super(Or, self).__init__()
  37         self.__patterns = patterns
  38     def match_distance(self, plugin):
  39         for pat in self.__patterns:
  40             d = pat.match_distance(plugin)
  41             if d is not None:
  42                 return d
  43         else:
  44             return None
  45
  46 class And(PluginPattern):
  47     def __init__(self, *patterns):
  48         super(And, self).__init__()
  49         self.__patterns = patterns
  50     def match_distance(self, plugin):
  51         distances = [ pat.match_distance(plugin) for pat in self.__patterns ]
  52         if None in distances:
  53             return None
  54         return max(distances)
  55
  56 class ParentOf(PluginPattern):
  57     """Assumes cls.mro() does not change over the live of the pattern object."""
  58     def __init__(self, pluginkey, cls):
  59         assert isinstance(cls, type)
  60         super(ParentOf, self).__init__()
  61         self.__pluginkey, self.__cls = pluginkey, cls
  62         self.__parentnames = [ class_fullname(parent_cls)
  63                                for parent_cls in cls.mro() ]
  64     def match_distance(self, plugin):
  65         candidates = plugin.listfield(self.__pluginkey)
  66         logger.debug("match_distance(%s) in %s ?", plugin, candidates)
  67         for candidate in candidates:
  68             try:
  69                 return self.__parentnames.index(candidate)
  70             except ValueError:
  71                 continue
  72         else:
  73             return None
  74     def __repr__(self):
  75         return "ParentOf(%r, %r)" % (self.__pluginkey, self.__cls)