Refactor packaging build helpers into dedicated modules (#388)

Split the old monolithic `setup.py` build logic into focused helper modules so that static builds are coordinated by dedicated utilities rather than one giant script.

Additional changes:
- Use fixed library versions  
- Use GNU mirror FTP for downloading related libraries

Author: mxamin

.github/workflows/wheels.yml

@@ -110,7 +110,7 @@ jobs:
         include: ${{ fromJson(needs.generate-wheels-matrix.outputs.include) }}
 
     env:
-      PYXMLSEC_LIBXML2_VERSION: 2.14.5
+      PYXMLSEC_LIBXML2_VERSION: 2.14.6
       PYXMLSEC_LIBXSLT_VERSION: 1.1.43
 
     steps:

.pre-commit-config.yaml

@@ -31,7 +31,7 @@ repos:
   rev: v1.18.2
   hooks:
     - id: mypy
-      exclude: (setup.py|tests/.*.py|doc/.*)
+      exclude: (setup.py|tests|build_support/.*.py|doc/.*)
       types: []
       files: ^.*.pyi?$
       additional_dependencies: [lxml-stubs, types-docutils]

build_support/__init__.py

@@ -0,0 +1,86 @@
+import os
+import sys
+from distutils import log
+from distutils.errors import DistutilsError
+
+from setuptools.command.build_ext import build_ext as build_ext_orig
+
+from .static_build import CrossCompileInfo, StaticBuildHelper
+
+
+class build_ext(build_ext_orig):
+    def info(self, message):
+        self.announce(message, level=log.INFO)
+
+    def run(self):
+        ext = self.ext_map['xmlsec']
+        self.debug = os.environ.get('PYXMLSEC_ENABLE_DEBUG', False)
+        self.static = os.environ.get('PYXMLSEC_STATIC_DEPS', False)
+        self.size_opt = os.environ.get('PYXMLSEC_OPTIMIZE_SIZE', True)
+
+        if self.static or sys.platform == 'win32':
+            helper = StaticBuildHelper(self)
+            helper.prepare(sys.platform)
+        else:
+            import pkgconfig
+
+            try:
+                config = pkgconfig.parse('xmlsec1')
+            except OSError as error:
+                raise DistutilsError('Unable to invoke pkg-config.') from error
+            except pkgconfig.PackageNotFoundError as error:
+                raise DistutilsError('xmlsec1 is not installed or not in path.') from error
+
+            if config is None or not config.get('libraries'):
+                raise DistutilsError('Bad or incomplete result returned from pkg-config.')
+
+            ext.define_macros.extend(config['define_macros'])
+            ext.include_dirs.extend(config['include_dirs'])
+            ext.library_dirs.extend(config['library_dirs'])
+            ext.libraries.extend(config['libraries'])
+
+        import lxml
+
+        ext.include_dirs.extend(lxml.get_include())
+
+        ext.define_macros.extend(
+            [('MODULE_NAME', self.distribution.metadata.name), ('MODULE_VERSION', self.distribution.metadata.version)]
+        )
+        for key, value in ext.define_macros:
+            if key == 'XMLSEC_CRYPTO' and not (value.startswith('"') and value.endswith('"')):
+                ext.define_macros.remove((key, value))
+                ext.define_macros.append((key, f'"{value}"'))
+                break
+
+        if sys.platform == 'win32':
+            ext.extra_compile_args.append('/Zi')
+        else:
+            ext.extra_compile_args.extend(
+                [
+                    '-g',
+                    '-std=c99',
+                    '-fPIC',
+                    '-fno-strict-aliasing',
+                    '-Wno-error=declaration-after-statement',
+                    '-Werror=implicit-function-declaration',
+                ]
+            )
+
+        if self.debug:
+            ext.define_macros.append(('PYXMLSEC_ENABLE_DEBUG', '1'))
+            if sys.platform == 'win32':
+                ext.extra_compile_args.append('/Od')
+            else:
+                ext.extra_compile_args.append('-Wall')
+                ext.extra_compile_args.append('-O0')
+        else:
+            if self.size_opt:
+                if sys.platform == 'win32':
+                    ext.extra_compile_args.append('/Os')
+                else:
+                    ext.extra_compile_args.append('-Os')
+
+        super().run()
+
+
+__all__ = ('CrossCompileInfo', 'build_ext')

build_support/build_ext.py

@@ -0,0 +1,29 @@
+import contextlib
+import json
+from urllib.request import Request, urlopen
+
+DEFAULT_USER_AGENT = 'https://github.com/xmlsec/python-xmlsec'
+DOWNLOAD_USER_AGENT = 'python-xmlsec build'
+
+
+def make_request(url, github_token=None, json_response=False):
+    headers = {'User-Agent': DEFAULT_USER_AGENT}
+    if github_token:
+        headers['authorization'] = 'Bearer ' + github_token
+    request = Request(url, headers=headers)
+    with contextlib.closing(urlopen(request)) as response:
+        charset = response.headers.get_content_charset() or 'utf-8'
+        content = response.read().decode(charset)
+        if json_response:
+            return json.loads(content)
+        return content
+
+
+def download_lib(url, filename):
+    request = Request(url, headers={'User-Agent': DOWNLOAD_USER_AGENT})
+    with urlopen(request) as response, open(filename, 'wb') as target:
+        while True:
+            chunk = response.read(8192)
+            if not chunk:
+                break
+            target.write(chunk)

build_support/network.py

@@ -0,0 +1,77 @@
+import html.parser
+import os
+import re
+from distutils import log
+from distutils.version import StrictVersion as Version
+
+from .network import make_request
+
+
+class HrefCollector(html.parser.HTMLParser):
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.hrefs = []
+
+    def handle_starttag(self, tag, attrs):
+        if tag == 'a':
+            for name, value in attrs:
+                if name == 'href':
+                    self.hrefs.append(value)
+
+
+def latest_release_from_html(url, matcher):
+    content = make_request(url)
+    collector = HrefCollector()
+    collector.feed(content)
+    hrefs = collector.hrefs
+
+    def comp(text):
+        try:
+            return Version(matcher.match(text).groupdict()['version'])
+        except (AttributeError, ValueError):
+            return Version('0.0')
+
+    latest = max(hrefs, key=comp)
+    return f'{url}/{latest}'
+
+
+def latest_release_from_gnome_org_cache(url, lib_name):
+    cache_url = f'{url}/cache.json'
+    cache = make_request(cache_url, json_response=True)
+    latest_version = cache[2][lib_name][-1]
+    latest_source = cache[1][lib_name][latest_version]['tar.xz']
+    return f'{url}/{latest_source}'
+
+
+def latest_release_json_from_github_api(repo):
+    api_url = f'https://api.github.com/repos/{repo}/releases/latest'
+    token = os.environ.get('GH_TOKEN')
+    if token:
+        log.info('Using GitHub token to avoid rate limiting')
+    return make_request(api_url, token, json_response=True)
+
+
+def latest_openssl_release():
+    return latest_release_json_from_github_api('openssl/openssl')['tarball_url']
+
+
+def latest_zlib_release():
+    return latest_release_from_html('https://zlib.net/fossils', re.compile('zlib-(?P<version>.*).tar.gz'))
+
+
+def latest_libiconv_release():
+    return latest_release_from_html('https://ftpmirror.gnu.org/libiconv', re.compile('libiconv-(?P<version>.*).tar.gz'))
+
+
+def latest_libxml2_release():
+    return latest_release_from_gnome_org_cache('https://download.gnome.org/sources/libxml2', 'libxml2')
+
+
+def latest_libxslt_release():
+    return latest_release_from_gnome_org_cache('https://download.gnome.org/sources/libxslt', 'libxslt')
+
+
+def latest_xmlsec_release():
+    assets = latest_release_json_from_github_api('lsh123/xmlsec')['assets']
+    (tar_gz,) = [asset for asset in assets if asset['name'].endswith('.tar.gz')]
+    return tar_gz['browser_download_url']