1 files changed, 103 insertions, 0 deletions
diff --git a/scripts/aconfig-to-metalava-flags.py b/scripts/aconfig-to-metalava-flags.py
new file mode 100644
index 000000000..efa85ecb3
--- /dev/null
+++ b/scripts/aconfig-to-metalava-flags.py
@@ -0,0 +1,103 @@
+#!/usr/bin/env python3
+
+# Copyright (C) 2025 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Converts a set of aconfig protobuf flags to a Metalava config file."""
+
+# Formatted using `pyformat -i scripts/aconfig-to-metalava-flags.py`
+
+import argparse
+import sys
+import xml.etree.ElementTree as ET
+
+from protos import aconfig_pb2
+
+_READ_ONLY = aconfig_pb2.flag_permission.READ_ONLY
+_ENABLED = aconfig_pb2.flag_state.ENABLED
+_DISABLED = aconfig_pb2.flag_state.DISABLED
+
+# The namespace of the Metalava config file.
+CONFIG_NS = 'http://www.google.com/tools/metalava/config'
+
+
+def config_name(tag: str):
+  """Create a QName in the config namespace.
+
+  :param:tag the name of the entity in the config namespace.
+  """
+  return f'{{{CONFIG_NS}}}{tag}'
+
+
+def main():
+  """Program entry point."""
+  args_parser = argparse.ArgumentParser(
+      description='Generate Metalava flags config from aconfig protobuf',
+  )
+  args_parser.add_argument(
+      'input',
+      help='The path to the aconfig protobuf file',
+  )
+  args = args_parser.parse_args(sys.argv[1:])
+
+  # Read the parsed_flags from the protobuf file.
+  with open(args.input, 'rb') as f:
+    parsed_flags = aconfig_pb2.parsed_flags.FromString(f.read())
+
+  # Create the structure of the XML config file.
+  config = ET.Element(config_name('config'))
+  api_flags = ET.SubElement(config, config_name('api-flags'))
+  # Create an <api-flag> element for each parsed_flag.
+  for flag in parsed_flags.parsed_flag:
+    if flag.permission == _READ_ONLY:
+      # Ignore any read only disabled flags as Metalava assumes that as the
+      # default when an <api-flags/> element is provided so this reduces the
+      # size of the file.
+      if flag.state == _DISABLED:
+        continue
+      mutability = 'immutable'
+    else:
+      mutability = 'mutable'
+    if flag.state == _ENABLED:
+      status = 'enabled'
+    else:
+      status = 'disabled'
+    attributes = {
+        'package': flag.package,
+        'name': flag.name,
+        'mutability': mutability,
+        'status': status,
+    }
+    # Convert the attribute names into qualified names in, what will become, the
+    # default namespace for the XML file. This is needed to ensure that the
+    # attribute will be written in the XML file without a prefix, e.g.
+    # `name="flag_name"`. Without it, a namespace prefix, e.g. `ns1`, will be
+    # synthesized for the attribute when writing the XML file, i.e. it
+    # will be written as `ns1:name="flag_name"`. Strictly speaking, that is
+    # unnecessary as the "Namespaces in XML 1.0 (Third Edition)" specification
+    # says that unprefixed attribute names have no namespace.
+    qualified_attributes = {config_name(k): v for (k, v) in attributes.items()}
+    ET.SubElement(api_flags, config_name('api-flag'), qualified_attributes)
+
+  # Create a tree and add white space so it will pretty print when written out.
+  tree = ET.ElementTree(config)
+  ET.indent(tree)
+
+  # Write the tree using the config namespace as the default.
+  tree.write(sys.stdout, encoding='unicode', default_namespace=CONFIG_NS)
+  sys.stdout.close()
+
+
+if __name__ == '__main__':
+  main()