src/mailman/styles/manager.py

   1 # Copyright (C) 2007-2016 by the Free Software Foundation, Inc.
   2 #
   3 # This file is part of GNU Mailman.
   4 #
   5 # GNU Mailman is free software: you can redistribute it and/or modify it under
   6 # the terms of the GNU General Public License as published by the Free
   7 # Software Foundation, either version 3 of the License, or (at your option)
   8 # any later version.
   9 #
  10 # GNU Mailman is distributed in the hope that it will be useful, but WITHOUT
  11 # ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12 # FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  13 # more details.
  14 #
  15 # You should have received a copy of the GNU General Public License along with
  16 # GNU Mailman.  If not, see <http://www.gnu.org/licenses/>.
  17
  18 """Style manager."""
  19
  20 from mailman import public
  21 from mailman.interfaces.configuration import ConfigurationUpdatedEvent
  22 from mailman.interfaces.styles import (
  23     DuplicateStyleError, IStyle, IStyleManager)
  24 from mailman.utilities.modules import find_components
  25 from zope.component import getUtility
  26 from zope.interface import implementer
  27 from zope.interface.verify import verifyObject
  28
  29
  30 @public
  31 @implementer(IStyleManager)
  32 class StyleManager:
  33     """The built-in style manager."""
  34
  35     def __init__(self):
  36         """Install all styles from the configuration files."""
  37         self._styles = {}
  38
  39     def populate(self):
  40         self._styles.clear()
  41         # Avoid circular imports.
  42         from mailman.config import config
  43         # Calculate the Python import paths to search.
  44         paths = filter(None, (path.strip()
  45                               for path in config.styles.paths.splitlines()))
  46         for path in paths:
  47             for style_class in find_components(path, IStyle):
  48                 style = style_class()
  49                 verifyObject(IStyle, style)
  50                 assert style.name not in self._styles, (
  51                     'Duplicate style "{}" found in {}'.format(
  52                         style.name, style_class))
  53                 self._styles[style.name] = style
  54
  55     def get(self, name):
  56         """See `IStyleManager`."""
  57         return self._styles.get(name)
  58
  59     @property
  60     def styles(self):
  61         """See `IStyleManager`."""
  62         for style_name in sorted(self._styles):
  63             yield self._styles[style_name]
  64
  65     def register(self, style):
  66         """See `IStyleManager`."""
  67         verifyObject(IStyle, style)
  68         if style.name in self._styles:
  69             raise DuplicateStyleError(style.name)
  70         self._styles[style.name] = style
  71
  72     def unregister(self, style):
  73         """See `IStyleManager`."""
  74         # Let KeyErrors percolate up.
  75         del self._styles[style.name]
  76
  77
  78 @public
  79 def handle_ConfigurationUpdatedEvent(event):
  80     if isinstance(event, ConfigurationUpdatedEvent):
  81         getUtility(IStyleManager).populate()