setup.py

#!/usr/bin/env python
from __future__ import print_function
from setuptools import setup, find_packages, Extension
from setuptools.command.build_ext import build_ext
from distutils.errors import DistutilsSetupError
from distutils import log
from distutils.dep_util import newer_group
from distutils.dir_util import mkpath
from distutils.file_util import copy_file
from distutils.util import get_platform
import pkg_resources
import struct
import subprocess
import sys
import os
import platform
from io import open
import re
import argparse
import shlex


# export BUILD_SKIA_FROM_SOURCE=0 to not build libskia when building extension
BUILD_SKIA_FROM_SOURCE = bool(int(os.environ.get("BUILD_SKIA_FROM_SOURCE", "1")))
# Use this to specify the directory where your pre-built skia is located
SKIA_LIBRARY_DIR = os.environ.get("SKIA_LIBRARY_DIR")

# check if minimum required Cython is available
cython_version_re = re.compile('\s*"cython\s*>=\s*([0-9][0-9\w\.]*)\s*"')
with open("pyproject.toml", "r", encoding="utf-8") as fp:
    for line in fp:
        m = cython_version_re.match(line)
        if m:
            cython_min_version = m.group(1)
            break
    else:
        sys.exit("error: could not parse cython version from pyproject.toml")
try:
    pkg_resources.require("cython >= %s" % cython_min_version)
except pkg_resources.ResolutionError:
    with_cython = False
else:
    with_cython = True

inside_sdist = os.path.exists("PKG-INFO")

argv = sys.argv[1:]

# bail out early if we are compiling the cython extension module
if {"build", "build_ext", "bdist_wheel", "install", "develop", "test"}.intersection(
    argv
) and not with_cython:
    sys.exit("error: the required Cython >= %s was not found" % cython_min_version)

needs_wheel = {"bdist_wheel"}.intersection(argv)
wheel = ["wheel"] if needs_wheel else []

setuptools_git_ls_files = ["setuptools_git_ls_files"] if os.path.isdir(".git") else []


class custom_build_ext(build_ext):
    """Custom 'build_ext' command which allows to pass compiler-specific
    'extra_compile_args', 'extra_link_args', 'define_macros' and
    'undef_macros' options.

    The value of the Extension class keywords can be provided as a dict,
    with the the compiler type as the keys (e.g. "unix", "mingw32", "msvc"),
    and the values containing the compiler-specific list of options.
    A special empty string '' key may be used for default options that
    apply to all the other compiler types except for those explicitly
    listed.
    """

    _library_builders = {}

    @classmethod
    def register_library_builder(cls, library_name, builder):
        """Associates a builder function with signature `func(str) -> str` to
        the given library_name. The builder is a callable that takes one
        parameter, a build directory (e.g. './build'), and returns the full
        directory path where the newly built library is located (e.g. a sub-
        directory of the base build dir).
        Builder functions will be called in `get_libraries` method.
        E.g. see `build_skia` function defined below.
        """
        cls._library_builders[library_name] = builder

    def finalize_options(self):
        if with_cython:
            # compile *.pyx source files to *.cpp using cythonize
            from Cython.Build import cythonize

            # optionally enable line tracing for test coverage support
            linetrace = os.environ.get("CYTHON_TRACE") == "1"
            force = linetrace or self.force
            self.distribution.ext_modules[:] = cythonize(
                self.distribution.ext_modules,
                force=force,
                annotate=os.environ.get("CYTHON_ANNOTATE", False),
                quiet=not self.verbose,
                compiler_directives={
                    "linetrace": linetrace,
                    "language_level": 3,
                    "embedsignature": True,
                },
            )

        build_ext.finalize_options(self)

    def build_extension(self, ext):
        sources = ext.sources
        if sources is None or not isinstance(sources, (list, tuple)):
            raise DistutilsSetupError(
                "in 'ext_modules' option (extension '%s'), "
                "'sources' must be present and must be "
                "a list of source filenames" % ext.name
            )
        sources = list(sources)

        ext_path = self.get_ext_fullpath(ext.name)
        depends = sources + ext.depends
        if not (self.force or newer_group(depends, ext_path, "newer")):
            log.debug("skipping '%s' extension (up-to-date)", ext.name)
            return
        else:
            log.info("building '%s' extension", ext.name)

        # Detect target language, if not provided
        language = ext.language or self.compiler.detect_language(sources)

        # do compiler specific customizations
        compiler_type = self.compiler.compiler_type

        # strip compile flags that are not valid for C++ to avoid warnings
        if compiler_type == "unix" and language == "c++":
            if "-Wstrict-prototypes" in self.compiler.compiler_so:
                self.compiler.compiler_so.remove("-Wstrict-prototypes")

        if isinstance(ext.extra_compile_args, dict):
            if compiler_type in ext.extra_compile_args:
                extra_compile_args = ext.extra_compile_args[compiler_type]
            else:
                extra_compile_args = ext.extra_compile_args.get("", [])
        else:
            extra_compile_args = ext.extra_compile_args or []

        if isinstance(ext.extra_link_args, dict):
            if compiler_type in ext.extra_link_args:
                extra_link_args = ext.extra_link_args[compiler_type]
            else:
                extra_link_args = ext.extra_link_args.get("", [])
        else:
            extra_link_args = ext.extra_link_args or []

        if isinstance(ext.define_macros, dict):
            if compiler_type in ext.define_macros:
                macros = ext.define_macros[compiler_type]
            else:
                macros = ext.define_macros.get("", [])
        else:
            macros = ext.define_macros or []

        if isinstance(ext.undef_macros, dict):
            for tp, undef in ext.undef_macros.items():
                if tp == compiler_type:
                    macros.append((undef,))
        else:
            for undef in ext.undef_macros:
                macros.append((undef,))

        if os.environ.get("CYTHON_TRACE") == "1":
            log.debug("adding -DCYTHON_TRACE to preprocessor macros")
            macros.append(("CYTHON_TRACE", 1))

        # compile the source code to object files.
        objects = self.compiler.compile(
            sources,
            output_dir=self.build_temp,
            macros=macros,
            include_dirs=ext.include_dirs,
            debug=self.debug,
            extra_postargs=extra_compile_args,
            depends=ext.depends,
        )

        # Now link the object files together into a "shared object"
        if ext.extra_objects:
            objects.extend(ext.extra_objects)

        self.compiler.link_shared_object(
            objects,
            ext_path,
            libraries=self.get_libraries(ext),
            library_dirs=ext.library_dirs,
            runtime_library_dirs=ext.runtime_library_dirs,
            extra_postargs=extra_link_args,
            export_symbols=self.get_export_symbols(ext),
            debug=self.debug,
            build_temp=self.build_temp,
            target_lang=language,
        )

    def get_libraries(self, ext):
        """Build all libraries for which a builder function is registered,
        and append the resulting directory path to the extension module's
        'library_dirs' list so that the linker can find.
        """
        for library in ext.libraries:
            if library in self._library_builders:
                library_dir = self._library_builders[library](self.build_temp)
                ext.library_dirs.append(library_dir)

        return build_ext.get_libraries(self, ext)

    def run(self):
        build_ext.run(self)
        if sys.platform == "win32":
            self._copy_windows_dlls()

    def _copy_windows_dlls(self):
        # copy DLLs next to the extension module
        for ext in self.extensions:
            for lib_name in ext.libraries:
                for lib_dir in ext.library_dirs:
                    dll_filename = lib_name + ".dll"
                    dll_fullpath = os.path.join(lib_dir, dll_filename)
                    if os.path.exists(dll_fullpath):
                        break
                else:
                    log.debug(
                        "cannot find '{}' in: {}".format(
                            dll_filename, ", ".join(ext.library_dirs)
                        )
                    )
                    continue

                ext_path = self.get_ext_fullpath(ext.name)
                dest_dir = os.path.dirname(ext_path)
                mkpath(dest_dir, verbose=self.verbose, dry_run=self.dry_run)
                copy_file(
                    dll_fullpath,
                    os.path.join(dest_dir, dll_filename),
                    verbose=self.verbose,
                    dry_run=self.dry_run,
                )


def build_skia(build_base):
    log.info("building 'skia' library")
    build_dir = os.path.join(build_base, skia_dir)
    build_skia_py = os.path.join(skia_builder_dir, "build_skia.py")
    build_cmd = [sys.executable, build_skia_py, build_dir]

    if inside_sdist:
        build_cmd.append("--no-sync-deps")

    env = os.environ
    target_cpu = None
    if sys.platform == "win32":
        from distutils._msvccompiler import _get_vc_env

        # for Windows, we want to build a shared skia.dll. If we build a static lib
        # then gn/ninja pass the /MT flag (static runtime library) instead of /MD,
        # and produce linker errors when building the python extension module
        build_cmd.append("--shared-lib")

        # update Visual C++ toolchain environment depending on python architecture
        target_cpu = "x64" if struct.calcsize("P") * 8 == 64 else "x86"
        env = os.environ.copy()
        env.update(_get_vc_env(target_cpu))
    elif {"macosx", "universal2"}.issubset(get_platform().split("-")):
        # if Python was built as a 'universal2' binary, we also try to build
        # a single library combining both x86_64 and arm64 architectures
        target_cpu = "universal2"

    if target_cpu:
        build_cmd.extend(["--target-cpu", target_cpu])

    subprocess.run(build_cmd, check=True, env=env)
    return build_dir


def get_skia_using_pkgconfig():
    """Runs `pkg-config --libs --cflags skia` and parses returned
    flags using argparse.
    """
    _parser = argparse.ArgumentParser()
    _parser.add_argument("-I", dest="include_dirs", action="append", default=[])
    _parser.add_argument("-L", dest="library_dirs", action="append", default=[])
    _parser.add_argument("-l", dest="libraries", action="append", default=[])

    if BUILD_SKIA_FROM_SOURCE:
        return _parser.parse_known_args([])[0]

    pkgconfig = os.environ.get("PKG_CONFIG", "pkg-config")
    log.info("Finding skia using pkg-config")
    try:
        op = subprocess.run(
            [pkgconfig, "--cflags", "--libs", "skia"],
            text=True,
            check=False,
            stdout=subprocess.PIPE,
            stderr=subprocess.PIPE,
        )
        stout = op.stdout
    except FileNotFoundError:
        stout = ""
    args, _ = _parser.parse_known_args(shlex.split(stout))
    return args


pkg_config_op = get_skia_using_pkgconfig()
if BUILD_SKIA_FROM_SOURCE:
    custom_build_ext.register_library_builder("skia", build_skia)


pkg_dir = os.path.join("src", "python")
skia_builder_dir = os.path.join("src", "cpp", "skia-builder")
skia_dir = os.path.join(skia_builder_dir, "skia")
skia_src_dir = os.path.join(skia_dir, "src")  # allow access to internals

include_dirs = [skia_dir, skia_src_dir, *pkg_config_op.include_dirs]

extra_compile_args = {
    "": [
        "-std=c++17",
    ]
    + (
        [
            # extra flags needed on macOS for C++11
            "-stdlib=libc++",
            "-mmacosx-version-min=10.9",
        ]
        if platform.system() == "Darwin"
        else []
    ),
    "msvc": [
        "/EHsc",
        "/Zi",
        "/std:c++17",
    ],
}

library_dirs = [SKIA_LIBRARY_DIR] if SKIA_LIBRARY_DIR is not None else []
library_dirs += pkg_config_op.library_dirs

extensions = [
    Extension(
        "pathops._pathops",
        sources=[
            os.path.join(pkg_dir, "pathops", "_pathops.pyx"),
        ],
        include_dirs=include_dirs,
        extra_compile_args=extra_compile_args,
        libraries=["skia", *pkg_config_op.libraries],
        library_dirs=library_dirs,
        language="c++",
    ),
]

with open("README.md", "r") as f:
    long_description = f.read()

version_file = os.path.join(pkg_dir, "pathops", "_version.py")

setup_params = dict(
    name="skia-pathops",
    use_scm_version={"write_to": version_file},
    description="Python access to operations on paths using the Skia library",
    url="https://github.com/fonttools/skia-pathops",
    long_description=long_description,
    long_description_content_type="text/markdown",
    author="Khaled Hosny, Cosimo Lupo",
    author_email="fonttools@googlegroups.com",
    license="BSD-3-Clause",
    package_dir={"": pkg_dir},
    packages=find_packages(pkg_dir),
    ext_modules=extensions,
    cmdclass={
        "build_ext": custom_build_ext,
    },
    setup_requires=["setuptools_scm"] + setuptools_git_ls_files + wheel,
    install_requires=[],
    extras_require={
        "testing": [
            "pytest",
            "coverage",
            "pytest-xdist",
            "pytest-randomly",
            # https://github.com/lgpage/pytest-cython/pull/5#issuecomment-742782671
            # "pytest-cython",
        ],
    },
    python_requires=">=3.8",
    zip_safe=False,
    classifiers=[
        "Development Status :: 4 - Beta",
        "Environment :: Console",
        "Intended Audience :: Developers",
        "License :: OSI Approved :: BSD License",
        "Operating System :: OS Independent",
        "Programming Language :: Python",
        "Programming Language :: Python :: 3",
        "Topic :: Multimedia :: Graphics",
        "Topic :: Multimedia :: Graphics :: Graphics Conversion",
    ],
)

if __name__ == "__main__":
    setup(**setup_params)