contrib: rename gen-sdk to gen-sdk.py

This puts it in scope for the Python linters.

contrib/macdeploy/gen-sdk.py

@@ -0,0 +1,93 @@
+#!/usr/bin/env python3
+import argparse
+import plistlib
+import pathlib
+import tarfile
+import os
+import contextlib
+
+@contextlib.contextmanager
+def cd(path):
+    """Context manager that restores PWD even if an exception was raised."""
+    old_pwd = os.getcwd()
+    os.chdir(str(path))
+    try:
+        yield
+    finally:
+        os.chdir(old_pwd)
+
+def run():
+    parser = argparse.ArgumentParser(
+        description=__doc__, formatter_class=argparse.RawTextHelpFormatter)
+
+    parser.add_argument('xcode_app', metavar='XCODEAPP', type=pathlib.Path)
+    parser.add_argument("-o", metavar='OUTSDKTAR', dest='out_sdkt', type=pathlib.Path, required=False)
+
+    args = parser.parse_args()
+
+    xcode_app = args.xcode_app.resolve()
+    assert xcode_app.is_dir(), "The supplied Xcode.app path '{}' either does not exist or is not a directory".format(xcode_app)
+
+    xcode_app_plist = xcode_app.joinpath("Contents/version.plist")
+    with xcode_app_plist.open('rb') as fp:
+        pl = plistlib.load(fp)
+        xcode_version = pl['CFBundleShortVersionString']
+        xcode_build_id = pl['ProductBuildVersion']
+    print("Found Xcode (version: {xcode_version}, build id: {xcode_build_id})".format(xcode_version=xcode_version, xcode_build_id=xcode_build_id))
+
+    sdk_dir = xcode_app.joinpath("Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk")
+    sdk_plist = sdk_dir.joinpath("System/Library/CoreServices/SystemVersion.plist")
+    with sdk_plist.open('rb') as fp:
+        pl = plistlib.load(fp)
+        sdk_version = pl['ProductVersion']
+        sdk_build_id = pl['ProductBuildVersion']
+    print("Found MacOSX SDK (version: {sdk_version}, build id: {sdk_build_id})".format(sdk_version=sdk_version, sdk_build_id=sdk_build_id))
+
+    out_name = "Xcode-{xcode_version}-{xcode_build_id}-extracted-SDK-with-libcxx-headers".format(xcode_version=xcode_version, xcode_build_id=xcode_build_id)
+
+    out_sdkt_path = args.out_sdkt or pathlib.Path("./{}.tar".format(out_name))
+
+    def tarfp_add_with_base_change(tarfp, dir_to_add, alt_base_dir):
+        """Add all files in dir_to_add to tarfp, but prepend alt_base_dir to the files'
+        names
+
+        e.g. if the only file under /root/bazdir is /root/bazdir/qux, invoking:
+
+            tarfp_add_with_base_change(tarfp, "foo/bar", "/root/bazdir")
+
+        would result in the following members being added to tarfp:
+
+            foo/bar/             -> corresponding to /root/bazdir
+            foo/bar/qux          -> corresponding to /root/bazdir/qux
+
+        """
+        def change_tarinfo_base(tarinfo):
+            if tarinfo.name and tarinfo.name.endswith((".swiftmodule", ".modulemap")):
+                return None
+            if tarinfo.name and tarinfo.name.startswith("./"):
+                tarinfo.name = str(pathlib.Path(alt_base_dir, tarinfo.name))
+            if tarinfo.linkname and tarinfo.linkname.startswith("./"):
+                tarinfo.linkname = str(pathlib.Path(alt_base_dir, tarinfo.linkname))
+            # make metadata deterministic
+            tarinfo.mtime = 0
+            tarinfo.uid, tarinfo.uname =  0, ''
+            tarinfo.gid, tarinfo.gname = 0, ''
+            # don't use isdir() as there are also executable files present
+            tarinfo.mode = 0o0755 if tarinfo.mode & 0o0100 else 0o0644
+            return tarinfo
+        with cd(dir_to_add):
+            # recursion already adds entries in sorted order
+            tarfp.add("./usr/include", recursive=True, filter=change_tarinfo_base)
+            tarfp.add("./usr/lib", recursive=True, filter=change_tarinfo_base)
+            tarfp.add("./System/Library/Frameworks", recursive=True, filter=change_tarinfo_base)
+
+    print("Creating output .tar file...")
+    with out_sdkt_path.open("wb") as fp:
+        with tarfile.open(mode="w", fileobj=fp, format=tarfile.PAX_FORMAT) as tarfp:
+            print("Adding MacOSX SDK {} files...".format(sdk_version))
+            tarfp_add_with_base_change(tarfp, sdk_dir, out_name)
+    print("Done! Find the resulting tarball at:")
+    print(out_sdkt_path.resolve())
+
+if __name__ == '__main__':
+    run()