publish zig to pypi

zig-pypi.py

# This is not original code, it's from https://github.com/ziglang/zig-pypi
# this copy's purpose is to add comments in order to understand how it works

import os
import hashlib
import urllib.request
from email.message import EmailMessage
from wheel.wheelfile import WheelFile, get_zipinfo_datetime
from zipfile import ZipInfo, ZIP_DEFLATED
import libarchive # from libarchive-c

# Apparently wheels as zip files need to have a date of Linux:0, and System 3
class ReproducibleWheelFile(WheelFile):
    def writestr(self, zinfo, *args, **kwargs):
        if not isinstance(zinfo, ZipInfo):
            raise ValueError("ZipInfo required")
        zinfo.date_time = (1980,1,1,0,0,0)
        zinfo.create_system = 3
        super().writestr(zinfo, *args, **kwargs)

# create an email message
def make_message(headers, payload=None):
    msg = EmailMessage()
    for name, value in headers.items():
        if isinstance(value, list):
            for value_part in value:
                msg[name] = value_part
        else:
            msg[name] = value
    if payload:
        msg.set_payload(payload)
    return msg

# stuff all the things in a zip file that's been conformed to Jan 1 1980, System 3
def write_wheel_file(filename, contents):
    with ReproducibleWheelFile(filename, 'w') as wheel:
        for member_info, member_source in contents.items():
            if not isinstance(member_info, ZipInfo):
                member_info = ZipInfo(member_info)
                member_info.external_attr = 0o644 << 16
            member_info.file_size = len(member_source)
            member_info.compress_type = ZIP_DEFLATED
            wheel.writestr(member_info, bytes(member_source))
    return filename

# create a well formed wheel filled with magic wheel juice
def write_wheel(out_dir, *, name, version, tag, metadata, description, contents):
    wheel_name = f'{name}-{version}-{tag}.whl'
    dist_info  = f'{name}-{version}.dist-info'
    return write_wheel_file(os.path.join(out_dir, wheel_name), {
        **contents,
        f'{dist_info}/METADATA': make_message({
            'Metadata-Version': '2.1',
            'Name': name,
            'Version': version,
            **metadata,
        }, description),
        f'{dist_info}/WHEEL': make_message({
            'Wheel-Version': '1.0',
            'Generator': 'ziglang make_wheels.py',
            'Root-Is-Purelib': 'false',
            'Tag': tag,
        }),
    })

# create the squeamy guts of a wheel given an archive of contents
# external README.pypi.md is also copied in
def write_ziglang_wheel(out_dir, *, version, platform, archive):
    contents = {}
    contents['ziglang/__init__.py'] = b''

    # run through the archive and add top level elements to the wheel
    with libarchive.memory_reader(archive) as archive:
        for entry in archive:
            entry_name = '/'.join(entry.name.split('/')[1:])
            if entry.isdir or not entry_name:
                continue

            zip_info = ZipInfo(f'ziglang/{entry_name}')
            zip_info.external_attr = (entry.mode & 0xFFFF) << 16
            contents[zip_info] = b''.join(entry.get_blocks())

            # if the archive entry is zig, gin up some fakeness
            # to satisfy pypi that it's a python wheel
            if entry_name.startswith('zig'):
                contents['ziglang/__main__.py'] = f'''\
import os, sys, subprocess
sys.exit(subprocess.call([
    os.path.join(os.path.dirname(__file__), "{entry_name}"),
    *sys.argv[1:]
]))
'''.encode('ascii')

    with open('README.pypi.md') as f:
        description = f.read()

    # finish manufacturing the wheel
    return write_wheel(out_dir,
        name='ziglang',
        version=version,
        tag=f'py3-none-{platform}',
        metadata={
            'Summary': 'Zig is a general-purpose programming language and toolchain for maintaining robust, optimal, and reusable software.',
            'Description-Content-Type': 'text/markdown',
            'License': 'MIT',
            'Classifier': [
                'License :: OSI Approved :: MIT License',
            ],
            'Project-URL': [
                'Homepage, https://ziglang.org',
                'Source Code, https://github.com/ziglang/zig-pypi',
                'Bug Tracker, https://github.com/ziglang/zig-pypi/issues',
            ],
            'Requires-Python': '~=3.5',
        },
        description=description,
        contents=contents,
    )


zig_version = '0.8.0'

# download each of the zig targets from ziglang.org, and create a wheel for it
for zig_platform, python_platform in {
    'windows-i386':   'win32',
    'windows-x86_64': 'win_amd64',
    'macos-x86_64':   'macosx_10_9_x86_64',
    'macos-aarch64':  'macosx_11_0_arm64',
    'linux-i386':     'manylinux_2_12_i686.manylinux2010_i686',
    'linux-x86_64':   'manylinux_2_12_x86_64.manylinux2010_x86_64',
    'linux-aarch64':  'manylinux_2_17_aarch64.manylinux2014_aarch64',
}.items():
    zig_url = f'https://ziglang.org/download/{zig_version}/zig-{zig_platform}-{zig_version}.' + \
              ('zip' if zig_platform.startswith('windows-') else 'tar.xz')
    with urllib.request.urlopen(zig_url) as request:
        zig_archive = request.read()
        print(f'{hashlib.sha256(zig_archive).hexdigest()} {zig_url}')

    wheel_path = write_ziglang_wheel('dist/',
        version=zig_version,
        platform=python_platform,
        archive=zig_archive)
    with open(wheel_path, 'rb') as wheel:
        print(f'  {hashlib.sha256(wheel.read()).hexdigest()} {wheel_path}')