New module to load historical config options information

Signed-off-by: Gilles Peskine <[email protected]>

scripts/mbedtls_framework/config_history.py

@@ -0,0 +1,57 @@
+"""Historical information about the library configuration.
+"""
+
+## Copyright The Mbed TLS Contributors
+## SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+
+import glob
+import os
+import re
+from typing import Dict, FrozenSet
+
+from . import build_tree
+
+class ConfigHistory:
+    """Historical information about the library configuration.
+    """
+
+    @staticmethod
+    def load_options(filename: str) -> FrozenSet[str]:
+        """Load the options from the given file.
+
+        The file must contain one option name per line, with no whitespace.
+        """
+        with open(filename) as inp:
+            return frozenset(inp.read().splitlines())
+
+    def load_history_files(self,
+                           variety: str,
+                           exclude_dict: Dict[str, Dict[str, FrozenSet[str]]]
+                           ) -> Dict[str, Dict[str, FrozenSet[str]]]:
+        """Load all files containing macro lists of the given variety"""
+        data = {} #type: Dict[str, Dict[str, FrozenSet[str]]]
+        glob_pattern = os.path.join(self._history_dir,
+                                    f'config-{variety}-*-*.txt')
+        for filename in sorted(glob.glob(glob_pattern)):
+            basename = os.path.splitext(os.path.basename(filename))[0]
+            m = re.match(r'config-\w+-(.*?)-(.*)', basename)
+            assert m is not None
+            (product, version) = m.groups()
+            options = self.load_options(filename)
+            exclude = exclude_dict.get(product, {}).get(version, frozenset())
+            data.setdefault(product, {})[version] = options - exclude
+        return data
+
+    def __init__(self) -> None:
+        """Load all files containing historical option lists."""
+        self._history_dir = os.path.join(build_tree.framework_root(), 'history')
+        self._options = self.load_history_files('options', {})
+        self._internal = self.load_history_files('adjust', self._options)
+
+    def options(self, product: str, version: str) -> FrozenSet[str]:
+        """The set of options in the given product version."""
+        return self._options[product][version]
+
+    def internal(self, product: str, version: str) -> FrozenSet[str]:
+        """The set of internal option-like macros in the given product version."""
+        return self._internal[product][version]