diff: add MLS level and range wrappers.

setools/diff/mls.py

@@ -0,0 +1,53 @@
+# Copyright 2016, Tresys Technology, LLC
+#
+# This file is part of SETools.
+#
+# SETools is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as
+# published by the Free Software Foundation, either version 2.1 of
+# the License, or (at your option) any later version.
+#
+# SETools is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with SETools.  If not, see
+# <http://www.gnu.org/licenses/>.
+#
+from .difference import SymbolWrapper, Wrapper
+
+
+class LevelWrapper(Wrapper):
+
+    """Wrap levels to allow comparisons."""
+
+    def __init__(self, level):
+        self.origin = level
+        self.sensitivity = SymbolWrapper(level.sensitivity)
+        self.categories = set(SymbolWrapper(c) for c in level.categories())
+
+    def __eq__(self, other):
+        return self.sensitivity == other.sensitivity and \
+               self.categories == other.categories
+
+
+class RangeWrapper(Wrapper):
+
+    """
+    Wrap ranges to allow comparisons.
+
+    This only compares the low and high levels of the range.
+    It does not detect additions/removals/modifications
+    to levels between the low and high levels of the range.
+    """
+
+    def __init__(self, range_):
+        self.origin = range_
+        self.low = LevelWrapper(range_.low)
+        self.high = LevelWrapper(range_.high)
+
+    def __eq__(self, other):
+        return self.low == other.low and \
+               self.high == other.high