libcpuid/SOURCES/0001-Python-Refactor-the-build-of-the-bindings.patch

From c2acc569714d0a72051e4e1d34053f4f080d757b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pavol=20=C5=BD=C3=A1=C4=8Dik?= <zacik.pa@gmail.com>
Date: Sun, 1 Sep 2024 19:37:37 +0200
Subject: [PATCH] Python: Refactor the build of the bindings

When building the binding, link the dynamic
C library as built by `make` instead of linking
the system-installed C library. This simplifies
packaging in Linux distributions and also the
build of the live docs.
---
 .readthedocs.yml                        |   7 +-
 python/pyproject.toml                   |   2 +-
 python/src/libcpuid/_ffi_build.py       | 116 +++++++++++++++++++++---
 python/src/libcpuid/_ffi_build_rtd.py   |  31 -------
 python/src/libcpuid/_ffi_build_utils.py | 105 ---------------------
 5 files changed, 105 insertions(+), 156 deletions(-)
 delete mode 100644 python/src/libcpuid/_ffi_build_rtd.py
 delete mode 100644 python/src/libcpuid/_ffi_build_utils.py

diff --git a/.readthedocs.yml b/.readthedocs.yml
index 0866584..8aa71c8 100644
--- a/.readthedocs.yml
+++ b/.readthedocs.yml
@@ -14,13 +14,10 @@ build:
     pre_install:
       - libtoolize
       - autoreconf --install
-      - mkdir ./install
-      - ./configure --prefix=`pwd`/install
+      - ./configure
       - make
-      - make install
       - pip install cffi
-      - python ./python/src/libcpuid/_ffi_build_rtd.py ./libcpuid/libcpuid.h ./install
-
+      - python python/src/libcpuid/_ffi_build.py --runtime-link
 sphinx:
   configuration: python/docs/conf.py
 
diff --git a/python/pyproject.toml b/python/pyproject.toml
index 637b0e6..580a4c7 100644
--- a/python/pyproject.toml
+++ b/python/pyproject.toml
@@ -1,5 +1,5 @@
 [build-system]
-requires = ["setuptools", "cffi"]
+requires = ["setuptools", "cffi", "wheel"]
 build-backend = "setuptools.build_meta"
 
 [project]
diff --git a/python/src/libcpuid/_ffi_build.py b/python/src/libcpuid/_ffi_build.py
index 6e24d12..e3a7ea0 100644
--- a/python/src/libcpuid/_ffi_build.py
+++ b/python/src/libcpuid/_ffi_build.py
@@ -3,23 +3,111 @@ Module for compiling the C FFI.
 """
 
 import os
-import sys
+import subprocess
+import tempfile
+import re
+import argparse
+from pathlib import Path
 from cffi import FFI
 
-sys.path.append(os.path.dirname(os.path.abspath(__file__)))
 
-from _ffi_build_utils import (  # pylint: disable=import-error, wrong-import-position
-    get_include_flags,
-    find_header_file,
-    preprocess_header,
-    eval_sizeofs,
+class FFIBuildException(Exception):
+    """Generic exception for errors occuring during the CFFI build."""
+
+
+def preprocess_header(header_path):
+    """
+    Preprocesses the header file (python-cffi only accepts preprocessed C definitions)
+    at the given path and returns it as a string.
+    """
+    try:
+        return subprocess.check_output(
+            ["gcc", "-U __GNUC__", "-E", header_path]
+        ).decode()
+    except subprocess.CalledProcessError as e:
+        if e.returncode == 127:
+            raise FFIBuildException(
+                "The gcc compiler is necessary to build python-libcpuid."
+            ) from e
+        raise FFIBuildException(
+            f"Error preprocessing the libcpuid header file: {e.stderr}"
+        ) from e
+
+
+def _get_sizeof_eval_source(sizeof):
+    return f"""
+#include <libcpuid.h>
+#include <stdio.h>
+
+int main() {{
+    printf("%ld", {sizeof});
+    return 0;
+}}
+"""
+
+
+def eval_sizeofs(header, cflags):
+    """
+    Evaluates each sizeof found in the given C header and replaces all
+    occurences of the sizeof with its computed value.
+    """
+    sizeofs = set(re.findall(r"sizeof\([^\)]*\)", header))
+    tmp_dir = tempfile.mkdtemp()
+    c_program_path = Path(tmp_dir, "sizeof.c")
+    executable_path = Path(tmp_dir, "sizeof")
+
+    for sizeof in sizeofs:
+        with open(c_program_path, "w", encoding="UTF-8") as c_program_file:
+            c_program_file.write(_get_sizeof_eval_source(sizeof))
+        subprocess.check_call(["gcc", c_program_path, *cflags, "-o", executable_path])
+        size = subprocess.check_output([executable_path]).decode()
+        header = header.replace(sizeof, size)
+
+    os.remove(c_program_path)
+    os.remove(executable_path)
+    os.rmdir(tmp_dir)
+    return header
+
+
+LIBCPUID_DIR = str(Path(*(Path(os.path.abspath(__file__)).parts[:-4])))
+LIBCPUID_INCLUDE_DIR = str(Path(LIBCPUID_DIR, "libcpuid"))
+LIBCPUID_LIBRARY_DIR = str(Path(LIBCPUID_DIR, "libcpuid", ".libs"))
+LIBCPUID_MAIN_HEADER_FILENAME = "libcpuid.h"
+LIBCPUID_MAIN_HEADER_PATH = str(
+    Path(LIBCPUID_INCLUDE_DIR, LIBCPUID_MAIN_HEADER_FILENAME)
 )
+LIBCPUID_LIBRARY_NAME = "cpuid"
+PYTHON_SRC_DIR = str(Path(LIBCPUID_DIR, "python", "src"))
+
+PREPROCESSED_HEADER = preprocess_header(LIBCPUID_MAIN_HEADER_PATH)
+EVAL_SIZEOF_CFLAGS = [
+    f"-I{LIBCPUID_INCLUDE_DIR}",
+    f"-L{LIBCPUID_LIBRARY_DIR}",
+    f"-l{LIBCPUID_LIBRARY_NAME}",
+    f"-Wl,-rpath={LIBCPUID_LIBRARY_DIR}",
+]
+
+NO_SIZEOF_HEADER = eval_sizeofs(PREPROCESSED_HEADER, EVAL_SIZEOF_CFLAGS)
 
-include_flags = get_include_flags()
-preprocessed_header = preprocess_header(find_header_file(include_flags))
-no_sizeof_header = eval_sizeofs(preprocessed_header, include_flags)
 ffibuilder = FFI()
-ffibuilder.cdef(no_sizeof_header)
-ffibuilder.set_source_pkgconfig(
-    "libcpuid._libcpuid_cffi", ["libcpuid"], "#include <libcpuid.h>"
-)
+ffibuilder.cdef(NO_SIZEOF_HEADER)
+
+set_source_kwargs = {
+    "module_name": "libcpuid._libcpuid_cffi",
+    "source": f"#include <{LIBCPUID_MAIN_HEADER_FILENAME}>",
+    "libraries": [LIBCPUID_LIBRARY_NAME],
+    "include_dirs": [LIBCPUID_INCLUDE_DIR],
+    "library_dirs": [LIBCPUID_LIBRARY_DIR],
+}
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser()
+    parser.add_argument("-r", "--runtime-link", action="store_true")
+    args = parser.parse_args()
+    if args.runtime_link:
+        set_source_kwargs["extra_link_args"] = [f"-Wl,-rpath={LIBCPUID_LIBRARY_DIR}"]
+
+ffibuilder.set_source(**set_source_kwargs)
+
+if __name__ == "__main__":
+    ffibuilder.compile(PYTHON_SRC_DIR)
diff --git a/python/src/libcpuid/_ffi_build_rtd.py b/python/src/libcpuid/_ffi_build_rtd.py
deleted file mode 100644
index 09d09ba..0000000
--- a/python/src/libcpuid/_ffi_build_rtd.py
+++ /dev/null
@@ -1,31 +0,0 @@
-"""
-Script for compiling the C FFI for the live documentation.
-"""
-
-import sys
-import os
-from cffi import FFI
-
-sys.path.append(os.path.dirname(os.path.abspath(__file__)))
-
-from _ffi_build_utils import (  # pylint: disable=import-error, wrong-import-position
-    preprocess_header,
-    eval_sizeofs,
-)
-
-if __name__ == "__main__":
-    header_path = sys.argv[1]
-    install_dir = sys.argv[2]
-    library_dir = os.path.join(os.getcwd(), install_dir, "lib")
-    include_dir = os.path.join(install_dir, "include", "libcpuid")
-    ffibuilder = FFI()
-    ffibuilder.cdef(eval_sizeofs(preprocess_header(header_path), [f"-I{include_dir}"]))
-    ffibuilder.set_source(
-        "python.src.libcpuid._libcpuid_cffi",
-        "#include <libcpuid.h>",
-        libraries=["cpuid"],
-        library_dirs=[library_dir],
-        include_dirs=[include_dir],
-        extra_link_args=[f"-Wl,-rpath={library_dir}"],
-    )
-    ffibuilder.compile(verbose=True)
diff --git a/python/src/libcpuid/_ffi_build_utils.py b/python/src/libcpuid/_ffi_build_utils.py
deleted file mode 100644
index 410bd8c..0000000
--- a/python/src/libcpuid/_ffi_build_utils.py
+++ /dev/null
@@ -1,105 +0,0 @@
-"""
-Utility functions for building the FFI.
-"""
-
-import subprocess
-import os
-import re
-import tempfile
-
-
-class FFIBuildException(Exception):
-    """Generic exception for errors occuring during the CFFI build."""
-
-
-def get_include_flags():
-    """
-    Obtains libcpuid include flags via pkg-config.
-    """
-    try:
-        cflags = (
-            subprocess.check_output(["pkg-config", "libcpuid", "--cflags-only-I"])
-            .decode()
-            .strip()
-            .split()
-        )
-        return cflags
-    except subprocess.CalledProcessError as e:
-        if e.returncode == 127:
-            raise FFIBuildException(
-                "The pkg-config command is necessary to build python-libcpuid."
-            ) from e
-        if e.returncode == 1:
-            raise FFIBuildException(
-                "The libcpuid C library (devel) was not found."
-            ) from e
-        raise FFIBuildException("Error looking for the libcpuid library") from e
-
-
-def find_header_file(include_flags):
-    """
-    Obtains main libcpuid header file location from include flags.
-    """
-    header_path = None  # pylint: disable=invalid-name
-    for cflag in include_flags:
-        header_candidate = os.path.join(cflag[2:], "libcpuid.h")
-        if os.path.isfile(header_candidate):
-            header_path = header_candidate
-            break
-    if header_path is None:
-        raise FFIBuildException("Could not find header file of the libcpuid library.")
-    return header_path
-
-
-def preprocess_header(header_path):
-    """
-    Preprocesses the header file (python-cffi only accepts preprocessed C definitions)
-    at the given path and returns it as a string.
-    """
-    try:
-        return subprocess.check_output(
-            ["gcc", "-U __GNUC__", "-E", header_path]
-        ).decode()
-    except subprocess.CalledProcessError as e:
-        if e.returncode == 127:
-            raise FFIBuildException(
-                "The gcc compiler is necessary to build python-libcpuid."
-            ) from e
-        raise FFIBuildException(
-            f"Error preprocessing the libcpuid header file: {e.stderr}"
-        ) from e
-
-
-def _get_sizeof_eval_source(sizeof):
-    return f"""
-#include <libcpuid.h>
-#include <stdio.h>
-
-int main() {{
-    printf("%ld", {sizeof});
-    return 0;
-}}
-"""
-
-
-def eval_sizeofs(header, cflags):
-    """
-    Evaluates each sizeof found in the given C header and replaces all
-    occurences of the sizeof with its computed value.
-    """
-    sizeofs = set(re.findall(r"sizeof\([^\)]*\)", header))
-    tmp_dir = tempfile.mkdtemp()
-    c_program_path = os.path.join(tmp_dir, "sizeof.c")
-    executable_path = os.path.join(tmp_dir, "sizeof")
-
-    for sizeof in sizeofs:
-        with open(c_program_path, "w", encoding="UTF-8") as c_program_file:
-            c_program_file.write(_get_sizeof_eval_source(sizeof))
-        subprocess.check_call(["gcc", c_program_path, *cflags, "-o", executable_path])
-        size = subprocess.check_output([executable_path]).decode()
-        header = header.replace(sizeof, size)
-
-    os.remove(c_program_path)
-    os.remove(executable_path)
-    os.rmdir(tmp_dir)
-    return header
-- 
2.46.0