# Copyright 2016, Tresys Technology, LLC
#
# SPDX-License-Identifier: LGPL-2.1-only
#
from typing import NamedTuple, Optional
from ..policyrep import Default, DefaultRuletype, DefaultValue, DefaultRangeValue, ObjClass
from .descriptors import DiffResultDescriptor
from .difference import Difference, SymbolWrapper, Wrapper
class ModifiedDefault(NamedTuple):
"""Difference details for a modified default_*."""
rule: Default
added_default: Optional[DefaultValue]
removed_default: Optional[DefaultValue]
added_default_range: Optional[DefaultRangeValue]
removed_default_range: Optional[DefaultRangeValue]
class DefaultsDifference(Difference):
"""Determine the difference in default_* between two policies."""
added_defaults = DiffResultDescriptor("diff_defaults")
removed_defaults = DiffResultDescriptor("diff_defaults")
modified_defaults = DiffResultDescriptor("diff_defaults")
def diff_defaults(self) -> None:
"""Generate the difference in type defaults between the policies."""
self.log.info(
"Generating default_* differences from {0.left_policy} to {0.right_policy}".
format(self))
self.added_defaults, self.removed_defaults, matched_defaults = self._set_diff(
(DefaultWrapper(d) for d in self.left_policy.defaults()),
(DefaultWrapper(d) for d in self.right_policy.defaults()))
self.modified_defaults = []
for left_default, right_default in matched_defaults:
# Criteria for modified defaults
# 1. change to default setting
# 2. change to default range
if left_default.default != right_default.default:
removed_default = left_default.default
added_default = right_default.default
else:
removed_default = None
added_default = None
try:
if left_default.default_range != right_default.default_range:
removed_default_range = left_default.default_range
added_default_range = right_default.default_range
else:
removed_default_range = None
added_default_range = None
except AttributeError:
removed_default_range = None
added_default_range = None
if removed_default or removed_default_range:
self.modified_defaults.append(
ModifiedDefault(left_default,
added_default,
removed_default,
added_default_range,
removed_default_range))
#
# Internal functions
#
def _reset_diff(self) -> None:
"""Reset diff results on policy changes."""
self.log.debug("Resetting default_* differences")
self.added_defaults = None
self.removed_defaults = None
self.modified_defaults = None
class DefaultWrapper(Wrapper[Default]):
"""Wrap default_* to allow comparisons."""
__slots__ = ("ruletype", "tclass")
def __init__(self, default: Default) -> None:
self.origin = default
self.ruletype = default.ruletype
self.tclass = SymbolWrapper(default.tclass)
self.key = hash(default)
def __hash__(self):
return self.key
def __lt__(self, other):
return self.key < other.key
def __eq__(self, other):
return self.ruletype == other.ruletype and \
self.tclass == other.tclass
