| # Copyright 2021 The Pigweed Authors |
| # |
| # 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 |
| # |
| # https://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. |
| """Mirrors a directory tree to another directory using hard links.""" |
| |
| import argparse |
| import os |
| from pathlib import Path |
| import shutil |
| from typing import Iterable, Iterator, List |
| |
| |
| def _parse_args() -> argparse.Namespace: |
| """Registers the script's arguments on an argument parser.""" |
| |
| parser = argparse.ArgumentParser(description=__doc__) |
| |
| parser.add_argument('--source-root', |
| type=Path, |
| required=True, |
| help='Prefix to strip from the source files') |
| parser.add_argument('sources', |
| type=Path, |
| nargs='*', |
| help='Files to mirror to the directory') |
| parser.add_argument('--directory', |
| type=Path, |
| required=True, |
| help='Directory to which to mirror the sources') |
| parser.add_argument('--path-file', |
| type=Path, |
| help='File with paths to files to mirror') |
| |
| return parser.parse_args() |
| |
| |
| def _link_files(source_root: Path, sources: Iterable[Path], |
| directory: Path) -> Iterator[Path]: |
| for source in sources: |
| dest = directory / source.relative_to(source_root) |
| dest.parent.mkdir(parents=True, exist_ok=True) |
| |
| if dest.exists(): |
| dest.unlink() |
| |
| # Use a hard link to avoid unnecessary copies. Resolve the source before |
| # linking in case it is a symlink. |
| source = source.resolve() |
| try: |
| os.link(source, dest) |
| yield dest |
| |
| # If the link failed try copying. If copying fails re-raise the |
| # original exception. |
| except OSError: |
| shutil.copy(source, dest) |
| yield dest |
| |
| |
| def _link_files_or_dirs(paths: Iterable[Path], |
| directory: Path) -> Iterator[Path]: |
| """Links files or directories into the output directory. |
| |
| Files are linked directly; files in directories are linked as relative paths |
| from the directory. |
| """ |
| |
| for path in paths: |
| if path.is_dir(): |
| files = (p for p in path.glob('**/*') if p.is_file()) |
| yield from _link_files(path, files, directory) |
| elif path.is_file(): |
| yield from _link_files(path.parent, [path], directory) |
| else: |
| raise FileNotFoundError(f'{path} does not exist!') |
| |
| |
| def mirror_paths(source_root: Path, |
| sources: Iterable[Path], |
| directory: Path, |
| path_file: Path = None) -> List[Path]: |
| """Creates hard links in the provided directory for the provided sources. |
| |
| Args: |
| source_root: Base path for files in sources. |
| sources: Files to link to from the directory. |
| directory: The output directory. |
| path_file: A file with file or directory paths to link to. |
| """ |
| directory.mkdir(parents=True, exist_ok=True) |
| |
| outputs = list(_link_files(source_root, sources, directory)) |
| |
| if path_file: |
| paths = (Path(p).resolve() for p in path_file.read_text().splitlines()) |
| outputs.extend(_link_files_or_dirs(paths, directory)) |
| |
| return outputs |
| |
| |
| if __name__ == '__main__': |
| mirror_paths(**vars(_parse_args())) |