update-constants.py

#!/usr/bin/env python3
# SPDX-License-Identifier: LGPL-2.1-or-later

import sys

def defines(file):
    lines = iter(open(file).read().splitlines())
    for line in lines:
        if line.startswith('#define SD_MESSAGE') and '_STR ' not in line:
            if line.endswith('\\'):
                line = line[:-1] + next(lines)
            _, name, value = line.split()
            assert 'SD_' in name
            assert 'SD_ID128_MAKE' in value
            yield name, value


def process(includefile, docfile, *headers):
    # Collects all messages from all headers and saves the sorted list back to
    # headers[0]. Writes includefile (C) and docfile (rst).

    # Collect all messages into a single sorted, deduplicated list
    defs = sum((list(defines(file)) for file in headers), start=[])
    defs = sorted(set(defs))

    with open(includefile, 'wt') as out:
        print(f'Writing {out.name}…')
        for name, value in defs:
            print(f'add_id(m, "{name}", {name}) JOINER', file=out)

    with open(headers[0], 'wt') as out:
        print(f'Writing {out.name}…')
        for name, value in defs:
            print(f'#define {name} {value}', file=out)

    old = open(docfile).read().splitlines()

    with open(docfile, 'wt') as out:
        print(f'Writing {out.name}…')
        for line in old:
            print(line, file=out)
            if 'autogenerated' in line:
                break
        for name, value in defs:
            print(f'   .. autoattribute:: systemd.id128.{name}', file=out)

if __name__ == '__main__':
    includefile = sys.argv[1]
    docfile = sys.argv[2]
    headers = sys.argv[3:]
    process(includefile, docfile, *headers)