contrib/python-zstandard/setup_zstd.py

fix: new extension for automatically modifying file contents

This change implements most of the corresponding proposal as discussed at the
4.4 and 4.6 sprints: https://www.mercurial-scm.org/wiki/AutomaticFormattingPlan

This change notably does not include parallel execution of the formatter/fixer
tools. It does allow for implementing that without affecting other areas of the
code.

I believe the test coverage to be good, but this is a hotbed of corner cases.

Differential Revision: https://phab.mercurial-scm.org/D2897

# Copyright (c) 2016-present, Gregory Szorc
# All rights reserved.
#
# This software may be modified and distributed under the terms
# of the BSD license. See the LICENSE file for details.

import os
from distutils.extension import Extension


zstd_sources = ['zstd/%s' % p for p in (
    'common/entropy_common.c',
    'common/error_private.c',
    'common/fse_decompress.c',
    'common/pool.c',
    'common/threading.c',
    'common/xxhash.c',
    'common/zstd_common.c',
    'compress/fse_compress.c',
    'compress/huf_compress.c',
    'compress/zstd_compress.c',
    'compress/zstdmt_compress.c',
    'decompress/huf_decompress.c',
    'decompress/zstd_decompress.c',
    'dictBuilder/cover.c',
    'dictBuilder/divsufsort.c',
    'dictBuilder/zdict.c',
)]

zstd_sources_legacy = ['zstd/%s' % p for p in (
    'deprecated/zbuff_common.c',
    'deprecated/zbuff_compress.c',
    'deprecated/zbuff_decompress.c',
    'legacy/zstd_v01.c',
    'legacy/zstd_v02.c',
    'legacy/zstd_v03.c',
    'legacy/zstd_v04.c',
    'legacy/zstd_v05.c',
    'legacy/zstd_v06.c',
    'legacy/zstd_v07.c'
)]

zstd_includes = [
    'c-ext',
    'zstd',
    'zstd/common',
    'zstd/compress',
    'zstd/decompress',
    'zstd/dictBuilder',
]

zstd_includes_legacy = [
    'zstd/deprecated',
    'zstd/legacy',
]

ext_sources = [
    'zstd.c',
    'c-ext/bufferutil.c',
    'c-ext/compressiondict.c',
    'c-ext/compressobj.c',
    'c-ext/compressor.c',
    'c-ext/compressoriterator.c',
    'c-ext/compressionparams.c',
    'c-ext/compressionwriter.c',
    'c-ext/constants.c',
    'c-ext/decompressobj.c',
    'c-ext/decompressor.c',
    'c-ext/decompressoriterator.c',
    'c-ext/decompressionwriter.c',
    'c-ext/frameparams.c',
]

zstd_depends = [
    'c-ext/python-zstandard.h',
]


def get_c_extension(support_legacy=False, name='zstd'):
    """Obtain a distutils.extension.Extension for the C extension."""
    root = os.path.abspath(os.path.dirname(__file__))

    sources = [os.path.join(root, p) for p in zstd_sources + ext_sources]
    if support_legacy:
        sources.extend([os.path.join(root, p) for p in zstd_sources_legacy])

    include_dirs = [os.path.join(root, d) for d in zstd_includes]
    if support_legacy:
        include_dirs.extend([os.path.join(root, d) for d in zstd_includes_legacy])

    depends = [os.path.join(root, p) for p in zstd_depends]

    extra_args = ['-DZSTD_MULTITHREAD']

    if support_legacy:
        extra_args.append('-DZSTD_LEGACY_SUPPORT=1')

    # TODO compile with optimizations.
    return Extension(name, sources,
                     include_dirs=include_dirs,
                     depends=depends,
                     extra_compile_args=extra_args)