New module to load lists of config and adjusted macros

Load the list of C preprocessor macros that are options in the configuration
file (`mbedtls/mbedtls_config.h` or `psa/crypto_config.h`), and the list of
C preprocessor macros that are defined in `*adjust*.h` but are not public
options (derived internal macros).

The new module `config_macros` supports both querying the current tree and
querying historical data saved by `save_config_macros.sh`, with the same
query interface. The part that queries historical data subsumes the
`config_history` module.

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

scripts/mbedtls_framework/config_history.py

@@ -1,4 +1,6 @@
 """Historical information about the library configuration.
+
+Note: this module is deprecated. Use config_macros.py instead.
 """
 
 ## Copyright The Mbed TLS Contributors

scripts/mbedtls_framework/config_macros.py

@@ -0,0 +1,99 @@
+"""Information about configuration macros and derived macros."""
+
+## 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 FrozenSet, Iterable, Iterator
+
+from . import build_tree
+
+
+class ConfigMacros:
+    """Information about configuration macros and derived macros."""
+
+    def __init__(self, public: FrozenSet[str], adjusted: FrozenSet[str]) -> None:
+        self._public = public
+        self._internal = adjusted - public
+
+    def options(self) -> FrozenSet[str]:
+        """The set of configuration options in this product."""
+        return self._public
+
+    def internal(self) -> FrozenSet[str]:
+        """The set of internal option-like macros in this product."""
+        return self._internal
+
+
+class Current(ConfigMacros):
+    """Information about config-like macros parsed from the source code."""
+
+    _PUBLIC_CONFIG_HEADERS = [
+        'include/mbedtls/mbedtls_config.h',
+        'include/psa/crypto_config.h',
+    ]
+
+    _ADJUST_CONFIG_HEADERS = [
+        'include/**/*adjust*.h',
+        'drivers/*/include/**/*adjust*.h',
+    ]
+
+    _DEFINE_RE = re.compile(r'[/ ]*# *define  *([A-Z_a-z][0-9A-Z_a-z]*)')
+
+    def _list_files(self, patterns: Iterable[str]) -> Iterator[str]:
+        """Yield files matching the given glob patterns."""
+        for pattern in patterns:
+            yield from glob.glob(os.path.join(self._root, self._submodule,
+                                              pattern),
+                                 recursive=True)
+
+    def _search_file(self, filename: str) -> Iterator[str]:
+        """Yield macros defined in the given file."""
+        with open(filename, encoding='utf-8') as input_:
+            for line in input_:
+                m = self._DEFINE_RE.match(line)
+                if m:
+                    yield m.group(1)
+
+    def _search_files(self, patterns: Iterable[str]) -> FrozenSet[str]:
+        """Yield macros defined in files matching the given glob patterns."""
+        return frozenset(element
+                         for filename in self._list_files(patterns)
+                         for element in self._search_file(filename))
+
+    def __init__(self, submodule: str = '') -> None:
+        """Look for macros defined in the given submodule's source tree.
+
+        If submodule is omitted or empty, look in the root module.
+        """
+        self._root = build_tree.guess_project_root()
+        self._submodule = submodule
+        public = self._search_files(self._PUBLIC_CONFIG_HEADERS)
+        adjusted = self._search_files(self._ADJUST_CONFIG_HEADERS)
+        super().__init__(public, adjusted)
+
+
+class History(ConfigMacros):
+    """Information about config-like macros in a previous version.
+
+    Load files created by ``framework/scripts/save_config_history.sh``.
+    """
+
+    def _load_file(self, basename: str) -> FrozenSet[str]:
+        """Load macro names from the given file in the history directory."""
+        filename = os.path.join(self._history_dir, basename)
+        with open(filename, encoding='ascii') as input_:
+            return frozenset(line.strip()
+                             for line in input_)
+
+    def __init__(self, project: str, version: str) -> None:
+        """Read information about the given project at the given version.
+
+        The information must be present in history files in the framework.
+        """
+        self._history_dir = os.path.join(build_tree.framework_root(), 'history')
+        public = self._load_file(f'config-options-{project}-{version}.txt')
+        adjusted = self._load_file(f'config-adjust-{project}-{version}.txt')
+        super().__init__(public, adjusted)