# Copyright 2016, Tresys Technology, LLC # Copyright 2018, Chris PeBenito <pebenito@ieee.org> # # SPDX-License-Identifier: LGPL-2.1-only # from collections import defaultdict from typing import NamedTuple, Set from ..policyrep import Type, TypeAttribute from .descriptors import DiffResultDescriptor from .difference import Difference, SymbolWrapper from .typing import SymbolCache _typeattr_cache: SymbolCache[TypeAttribute] = defaultdict(dict) class ModifiedTypeAttribute(NamedTuple): """Difference details for a modified type attribute.""" added_types: Set[Type] removed_types: Set[Type] matched_types: Set[Type] def typeattr_wrapper_factory(attr: TypeAttribute) -> SymbolWrapper[TypeAttribute]: """ Wrap type attributes from the specified policy. This caches results to prevent duplicate wrapper objects in memory. """ try: return _typeattr_cache[attr.policy][attr] except KeyError: a = SymbolWrapper(attr) _typeattr_cache[attr.policy][attr] = a return a class TypeAttributesDifference(Difference): """Determine the difference in type attributes between two policies.""" added_type_attributes = DiffResultDescriptor("diff_type_attributes") removed_type_attributes = DiffResultDescriptor("diff_type_attributes") modified_type_attributes = DiffResultDescriptor("diff_type_attributes") def diff_type_attributes(self) -> None: """Generate the difference in type attributes between the policies.""" self.log.info( "Generating type attribute differences from {0.left_policy} to {0.right_policy}". format(self)) self.added_type_attributes, self.removed_type_attributes, matched_attributes = \ self._set_diff( (SymbolWrapper(r) for r in self.left_policy.typeattributes()), (SymbolWrapper(r) for r in self.right_policy.typeattributes())) self.modified_type_attributes = dict() for left_attribute, right_attribute in matched_attributes: # Criteria for modified attributes # 1. change to type set added_types, removed_types, matched_types = self._set_diff( (SymbolWrapper(t) for t in left_attribute.expand()), (SymbolWrapper(t) for t in right_attribute.expand())) if added_types or removed_types: self.modified_type_attributes[left_attribute] = ModifiedTypeAttribute( added_types, removed_types, matched_types) # # Internal functions # def _reset_diff(self) -> None: """Reset diff results on policy changes.""" self.log.debug("Resetting type attribute differences") self.added_type_attributes = None self.removed_type_attributes = None self.modified_type_attributes = None