simplify building (#26)

_shim_setup.py

@@ -0,0 +1,73 @@
+"""Shim setup.py: downloads pre-built wheels from GitHub Releases at install time."""
+import os
+import platform
+import zipfile
+from io import BytesIO
+from urllib.request import urlopen
+
+try:
+  import tomllib
+except ImportError:
+  import tomli as tomllib
+
+from setuptools import setup
+from setuptools.command.build_py import build_py
+
+_HERE = os.path.dirname(os.path.abspath(__file__))
+with open(os.path.join(_HERE, "pyproject.toml"), "rb") as _f:
+  _cfg = tomllib.load(_f)
+
+REPO_URL = _cfg["tool"]["shim"]["repo_url"]
+TAG = _cfg["tool"]["shim"]["tag"]
+DATADIR = _cfg["tool"]["shim"]["datadir"]
+VERSION = _cfg["project"]["version"]
+MODULE = _cfg["project"]["name"].replace("-", "_")
+
+PLATFORM_MAP = {
+  ("Linux", "x86_64"): "linux_x86_64",
+  ("Linux", "aarch64"): "linux_aarch64",
+  ("Darwin", "arm64"): "macosx_11_0_arm64",
+}
+
+
+class InstallPrebuilt(build_py):
+  def run(self):
+    data_dir = os.path.join(_HERE, MODULE, DATADIR)
+
+    if not os.path.exists(os.path.join(data_dir, "bin")):
+      key = (platform.system(), platform.machine())
+      plat = PLATFORM_MAP.get(key)
+      if plat is None:
+        raise RuntimeError(f"unsupported platform: {key}")
+
+      whl_name = f"{MODULE}-{VERSION}-py3-none-{plat}.whl"
+      url = f"{REPO_URL}/releases/download/{TAG}/{whl_name}"
+
+      print(f"Downloading {url} ...")
+      raw = urlopen(url).read()
+
+      print(f"Extracting {DATADIR} ...")
+      with zipfile.ZipFile(BytesIO(raw)) as zf:
+        prefix = f"{MODULE}/{DATADIR}/"
+        alt_prefix = f"{MODULE}-{VERSION}.data/purelib/{MODULE}/{DATADIR}/"
+        for info in zf.infolist():
+          for p in (prefix, alt_prefix):
+            if info.filename.startswith(p):
+              rel = info.filename[len(p):]
+              if not rel:
+                continue
+              dest = os.path.join(data_dir, rel)
+              if info.is_dir():
+                os.makedirs(dest, exist_ok=True)
+              else:
+                os.makedirs(os.path.dirname(dest), exist_ok=True)
+                with open(dest, "wb") as f:
+                  f.write(zf.read(info))
+                if info.external_attr >> 16 & 0o111:
+                  os.chmod(dest, 0o755)
+              break
+
+    super().run()
+
+
+setup(cmdclass={"build_py": InstallPrebuilt})