Modernize C builds with offline dependencies and portable runtime helpers

scripts/git_archive.sh

@@ -1,44 +1,14 @@
 #!/usr/bin/env bash
-set -e
-
-archive() {
-    export TARBALL_NAME=$1
-    export TARBALL_OUTDIR=$2
-
-    # archive this repo
-    cd "$(git rev-parse --show-toplevel)"
-    git archive HEAD --format=tar --prefix="${TARBALL_NAME}/" \
-        -o "${TARBALL_OUTDIR}/${TARBALL_NAME}.tar"
-    # archive submodules
-    git submodule update --init
-    git submodule foreach --quiet 'git archive HEAD --format=tar \
-            --prefix="${TARBALL_NAME}/${path}/" \
-            -o "${TARBALL_OUTDIR}/${TARBALL_NAME}-submodule-${path}-${sha1}.tar"
-        tar -n --concatenate --file="${TARBALL_OUTDIR}/${TARBALL_NAME}.tar" \
-            "${TARBALL_OUTDIR}/${TARBALL_NAME}-submodule-${path}-${sha1}.tar"'
-    gzip -c "${TARBALL_OUTDIR}/${TARBALL_NAME}.tar" > "${TARBALL_OUTDIR}/${TARBALL_NAME}.tar.gz"
-
-    # clean-up
-    git submodule foreach --quiet 'rm ${TARBALL_OUTDIR}/${TARBALL_NAME}-submodule-${path}-${sha1}.tar'
-    rm "${TARBALL_OUTDIR}/${TARBALL_NAME}.tar"
-}
-
-TARGET_TARBALL_NAME=shadowsocks-libev
-TARGET_TARBALL_DIR=$(git rev-parse --show-toplevel)
-
-while getopts "n:o:" opt
-do
-    case ${opt} in
-        o)
-            TARGET_TARBALL_DIR=$(readlink -f -- $OPTARG)
-            ;;
-        n)
-            TARGET_TARBALL_NAME=$OPTARG
-            ;;
-        \?)
-            exit 1
-            ;;
+# Backward-compatible maintainer entrypoint for the offline release archive.
+set -euo pipefail
+root=$(git rev-parse --show-toplevel)
+name=shadowsocks-libev
+directory=$root
+while getopts "n:o:" opt; do
+    case "$opt" in
+        n) name=$OPTARG ;;
+        o) directory=$OPTARG ;;
+        *) exit 1 ;;
     esac
 done
-
-archive "${TARGET_TARBALL_NAME}" "${TARGET_TARBALL_DIR}"
+exec python3 "$root/scripts/source_archive.py" "$directory/$name.tar.gz" --prefix "$name"

scripts/source_archive.py

@@ -0,0 +1,54 @@
+#!/usr/bin/env python3
+"""Create an offline source archive from Git's tracked working-tree files.
+
+Maintainer-only tool; building the resulting archive needs neither Git nor
+Python (unless integration tests or generated documentation are requested).
+"""
+import argparse
+import gzip
+import io
+import os
+from pathlib import Path
+import subprocess
+import tarfile
+
+
+def main():
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument("output", type=Path)
+    parser.add_argument("--prefix", default="shadowsocks-libev-3.3.6")
+    args = parser.parse_args()
+    root = Path(__file__).resolve().parents[1]
+    if "/" in args.prefix or args.prefix in ("", ".", ".."):
+        parser.error("prefix must be a single directory name")
+    epoch = int(os.environ.get("SOURCE_DATE_EPOCH") or subprocess.check_output(
+        ["git", "show", "-s", "--format=%ct", "HEAD"], cwd=root, text=True).strip())
+    entries = subprocess.check_output(["git", "ls-files", "--stage", "-z"], cwd=root).split(b"\0")
+    args.output.parent.mkdir(parents=True, exist_ok=True)
+    with args.output.open("wb") as raw, gzip.GzipFile(filename="", mode="wb", fileobj=raw, mtime=epoch) as compressed:
+        with tarfile.open(fileobj=compressed, mode="w|") as archive:
+            for entry in entries:
+                if not entry:
+                    continue
+                metadata, encoded = entry.split(b"\t", 1)
+                mode, _, stage = metadata.split()
+                if stage != b"0" or mode == b"160000":
+                    raise RuntimeError("Unmerged entry or submodule in source archive")
+                relative = os.fsdecode(encoded)
+                path = root / relative
+                info = tarfile.TarInfo(args.prefix + "/" + relative)
+                info.mtime = epoch
+                info.mode = int(mode, 8) & 0o777
+                if path.is_symlink():
+                    info.type = tarfile.SYMTYPE
+                    info.linkname = os.readlink(path)
+                    archive.addfile(info)
+                else:
+                    content = path.read_bytes()
+                    info.size = len(content)
+                    archive.addfile(info, io.BytesIO(content))
+    print(args.output)
+
+
+if __name__ == "__main__":
+    main()