81 lines
2.7 KiB
Python
81 lines
2.7 KiB
Python
#!/usr/bin/python
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# -*- coding: utf-8 -*-
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#
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# Copyright 2012 The Plaso Project Authors.
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# Please see the AUTHORS file for details on individual authors.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""This file contains a class registration system for plugins."""
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import abc
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class MetaclassRegistry(abc.ABCMeta):
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"""Automatic Plugin Registration through metaclasses."""
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def __init__(cls, name, bases, env_dict):
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"""Initialize a metaclass.
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Args:
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name: The interface class name.
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bases: A tuple of base names.
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env_dict: The namespace of the object.
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Raises:
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KeyError: If a classes given name is already registered, to make sure
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no two classes that inherit from the same interface can have
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the same name attribute.
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"""
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abc.ABCMeta.__init__(cls, name, bases, env_dict)
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# Register the name of the immediate parent class.
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if bases:
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cls.parent_class_name = getattr(bases[0], 'NAME', bases[0])
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cls.parent_class = bases[0]
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# Attach the classes dict to the baseclass and have all derived classes
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# use the same one:
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for base in bases:
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try:
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cls.classes = base.classes
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cls.plugin_feature = base.plugin_feature
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cls.top_level_class = base.top_level_class
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break
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except AttributeError:
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cls.classes = {}
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cls.plugin_feature = cls.__name__
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# Keep a reference to the top level class
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cls.top_level_class = cls
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# The following should not be registered as they are abstract. Classes
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# are abstract if the have the __abstract attribute (note this is not
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# inheritable so each abstract class must be explicitely marked).
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abstract_attribute = '_{0:s}__abstract'.format(name)
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if getattr(cls, abstract_attribute, None):
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return
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if not cls.__name__.startswith('Abstract'):
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cls_name = getattr(cls, 'NAME', cls.__name__)
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if cls_name in cls.classes:
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raise KeyError(u'Class: {0:s} already registered. [{1:s}]'.format(
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cls_name, repr(cls)))
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cls.classes[cls_name] = cls
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try:
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if cls.top_level_class.include_plugins_as_attributes:
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setattr(cls.top_level_class, cls.__name__, cls)
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except AttributeError:
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pass
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