File size: 2,381 Bytes
c8beaf3 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 | #!/usr/bin/env python3
"""Reassemble the nine immutable S4 transport parts after verifying each part."""
from __future__ import annotations
import argparse
import csv
import hashlib
from pathlib import Path
LOGICAL_BYTES = 66_637_933_197
LOGICAL_SHA256 = "44086cd8c71bfe5469b2d9f76a3270fc2b1fe1bf72c49c581633a9142e04a6fb"
def sha256_file(path: Path) -> str:
digest = hashlib.sha256()
with path.open("rb") as handle:
for chunk in iter(lambda: handle.read(8 * 1024 * 1024), b""):
digest.update(chunk)
return digest.hexdigest()
def main() -> int:
root = Path(__file__).resolve().parents[1]
parser = argparse.ArgumentParser()
parser.add_argument("--parts-dir", type=Path, required=True)
parser.add_argument("--output", type=Path, required=True)
parser.add_argument("--dependencies", type=Path, default=root / "dependencies" / "DEPENDENCIES.tsv")
args = parser.parse_args()
with args.dependencies.open("r", encoding="utf-8", newline="") as handle:
rows = [row for row in csv.DictReader(handle, delimiter="\t") if row["component"] == "S4"]
rows.sort(key=lambda row: row["repository_path"])
if len(rows) != 9 or any(row["assembly_method"] != "concat_s4_v1" for row in rows):
raise ValueError("S4 dependency lock is not the approved nine-part concat_s4_v1 layout")
digest = hashlib.sha256()
size = 0
partial = args.output.with_suffix(args.output.suffix + ".partial")
with partial.open("wb") as out:
for row in rows:
part = args.parts_dir / Path(row["repository_path"]).name
if part.stat().st_size != int(row["bytes"]) or sha256_file(part) != row["sha256"]:
raise ValueError(f"part verification failed: {part}")
with part.open("rb") as source:
for chunk in iter(lambda: source.read(8 * 1024 * 1024), b""):
out.write(chunk)
digest.update(chunk)
size += len(chunk)
actual = digest.hexdigest()
if size != LOGICAL_BYTES or actual != LOGICAL_SHA256:
partial.unlink(missing_ok=True)
raise ValueError(f"logical S4 mismatch: bytes={size}, sha256={actual}")
partial.replace(args.output)
print(f"PASS: {args.output} ({size:,} bytes; SHA-256 {actual})")
return 0
if __name__ == "__main__":
raise SystemExit(main())
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