bootstrap_spsc.py

1#!/usr/bin/env python32"""Verify bundled SPSC headers and licenses, or restore missing pinned files; never execute downloads."""3import argparse4import base645import hashlib6import json7from pathlib import Path8import urllib.request91011def digest(path):12    return hashlib.sha256(path.read_bytes()).hexdigest()131415def fetch(dep, entry):16    headers = {"User-Agent": "TwoBufQueue-SPSC-benchmark"}17    try:18        request = urllib.request.Request(entry["url"], headers=headers)19        with urllib.request.urlopen(request, timeout=30) as response:20            return response.read()21    except OSError:22        url = "https://api.github.com/repos/{}/contents/{}?ref={}".format(23            dep["repository"], entry["path"], dep["commit"])24        with urllib.request.urlopen(urllib.request.Request(url, headers=headers), timeout=30) as response:25            return base64.b64decode(json.load(response)["content"])262728def main():29    parser = argparse.ArgumentParser(description=__doc__)30    parser.add_argument("--output", type=Path, default=Path(__file__).resolve().parents[2] / "third_party/spsc")31    parser.add_argument("--check-only", action="store_true")32    args = parser.parse_args()33    manifest = json.loads(Path(__file__).with_name("spsc_dependencies.json").read_text())34    for name, dep in manifest.items():35        for entry in dep["files"]:36            target = args.output / name / entry["path"]37            if target.exists():38                if digest(target) != entry["sha256"]:39                    raise RuntimeError("SHA256 mismatch: {}".format(target))40                continue41            if args.check_only:42                raise RuntimeError("Missing dependency: {}".format(target))43            data = fetch(dep, entry)44            if hashlib.sha256(data).hexdigest() != entry["sha256"]:45                raise RuntimeError("Downloaded SHA256 mismatch: {}".format(target))46            target.parent.mkdir(parents=True, exist_ok=True)47            temporary = target.with_name(target.name + ".download")48            temporary.write_bytes(data)49            temporary.replace(target)50            print("Fetched", name, entry["path"], flush=True)51    print("Pinned SPSC dependencies verified:", args.output.resolve())525354if __name__ == "__main__":55    main()