xref: /aosp_15_r20/external/pigweed/pw_build/py/pw_build/file_prefix_map.py (revision 61c4878ac05f98d0ceed94b57d316916de578985) 
1# Copyright 2022 The Pigweed Authors
2#
3# Licensed under the Apache License, Version 2.0 (the "License"); you may not
4# use this file except in compliance with the License. You may obtain a copy of
5# the License at
6#
7#     https://www.apache.org/licenses/LICENSE-2.0
8#
9# Unless required by applicable law or agreed to in writing, software
10# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
11# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
12# License for the specific language governing permissions and limitations under
13# the License.
14"""Transforms a JSON list of paths using -ffile-prefix-map style rules."""
15
16import argparse
17import json
18from typing import Iterator, TextIO
19
20# Note: This should be list[tuple[str, str]], but using string.split()
21# produces tuple[Any,...], so this permits that typing for convenience.
22PrefixMaps = list[tuple]
23
24
25def _parse_args() -> argparse.Namespace:
26    """Parses and returns the command line arguments."""
27
28    parser = argparse.ArgumentParser(description=__doc__)
29    parser.add_argument(
30        'in_json',
31        type=argparse.FileType('r'),
32        help='The JSON file containing a list of file names '
33        'that the prefix map operations should be applied to',
34    )
35    parser.add_argument(
36        '--prefix-map-json',
37        type=argparse.FileType('r'),
38        required=True,
39        help=(
40            'JSON file containing an array of prefix map transformations to '
41            'apply to the strings before tokenizing. These string literal '
42            'transformations are of the form "from=to". All strings with the '
43            'prefix `from` will have the prefix replaced with `to`. '
44            'Transformations are applied in the order they are listed in the '
45            'JSON file.'
46        ),
47    )
48
49    parser.add_argument(
50        '--output',
51        type=argparse.FileType('w'),
52        help='File path to write transformed paths to.',
53    )
54    return parser.parse_args()
55
56
57def remap_paths(paths: list[str], prefix_maps: PrefixMaps) -> Iterator[str]:
58    for path in paths:
59        for from_prefix, to_prefix in prefix_maps:
60            if path.startswith(from_prefix):
61                path = path.replace(from_prefix, to_prefix, 1)
62                break  # Only the first -ffile-prefix-map option applies.
63        yield path
64
65
66def remap_json_paths(
67    in_json: TextIO, output: TextIO, prefix_map_json: TextIO
68) -> None:
69    paths = json.load(in_json)
70    prefix_maps: PrefixMaps = [
71        tuple(m.split('=', maxsplit=1)) for m in json.load(prefix_map_json)
72    ]
73
74    json.dump(list(remap_paths(paths, prefix_maps)), output)
75
76
77if __name__ == '__main__':
78    remap_json_paths(**vars(_parse_args()))
79