Files
libretro/scripts/largefiles.py
T
Abdessamad Derraz b5fd643ccf refactor: give common.py's parts their own modules
common.py had grown to 1833 lines by accumulation. Six coherent pieces
move out - untrusted parsing, digests, archives, generated artefacts,
release assets, dump catalogues - and common.py re-exports them, so the
sixty existing import sites keep working and migrating them stays
optional.

The site build is now reproducible, which is what made the move
checkable. It deleted its generated directories first, so every page was
new and write_if_changed had no earlier version to compare against: a
deploy republished six hundred pages for the clock alone. Directories
are swept instead, a page is removed only once nothing produces it, and
the body pass compares against the body of the file on disk rather than
against the decorated page. Two consecutive builds on the same inputs
now produce identical bytes; before, 1034 files differed.
2026-08-12 11:49:54 +02:00

107 lines
3.4 KiB
Python

"""Files too large for the repository.
They live as release assets and are fetched at build time, verified
against the hash the caller declares."""
from __future__ import annotations
import os
import tempfile
import urllib.error
import urllib.request
from hashing import compute_hashes
LARGE_FILES_RELEASE = "large-files"
LARGE_FILES_RELEASE = "large-files"
LARGE_FILES_REPO = "Abdess/retrobios"
LARGE_FILES_REPO = "Abdess/retrobios"
LARGE_FILES_CACHE = ".cache/large"
def fetch_large_file(
name: str,
dest_dir: str = LARGE_FILES_CACHE,
expected_sha1: str = "",
expected_md5: str = "",
*,
offline: bool = False,
) -> str | None:
"""Return a verified cached large file, downloading it only when allowed."""
cached = os.path.join(dest_dir, name)
if os.path.exists(cached):
if expected_sha1 or expected_md5:
hashes = compute_hashes(cached)
if expected_sha1 and hashes["sha1"].lower() != expected_sha1.lower():
os.unlink(cached)
elif expected_md5:
md5_list = [
m.strip().lower() for m in expected_md5.split(",") if m.strip()
]
if hashes["md5"].lower() not in md5_list:
os.unlink(cached)
else:
return cached
else:
return cached
else:
return cached
if offline:
return None
os.makedirs(dest_dir, exist_ok=True)
# A per-process scratch name: two runs fetching the same asset into one
# shared path interleave their writes into a full-size, corrupt file.
tmp_fd, tmp_path = tempfile.mkstemp(
dir=dest_dir, prefix=os.path.basename(cached) + ".", suffix=".tmp"
)
os.close(tmp_fd)
# GitHub rewrites spaces to dots in release asset names, so a file whose
# name contains spaces is published under a dotted name.
candidates = [name]
if " " in name:
candidates.append(name.replace(" ", "."))
downloaded = False
for candidate in candidates:
encoded_name = urllib.parse.quote(candidate)
url = (
f"https://github.com/{LARGE_FILES_REPO}/releases/download/"
f"{LARGE_FILES_RELEASE}/{encoded_name}"
)
try:
req = urllib.request.Request(url, headers={"User-Agent": "retrobios/1.0"})
with urllib.request.urlopen(req, timeout=300) as resp:
with open(tmp_path, "wb") as f:
while True:
chunk = resp.read(65536)
if not chunk:
break
f.write(chunk)
downloaded = True
break
except (urllib.error.URLError, urllib.error.HTTPError):
if os.path.exists(tmp_path):
os.unlink(tmp_path)
if not downloaded:
if os.path.exists(tmp_path):
os.unlink(tmp_path)
return None
if expected_sha1 or expected_md5:
hashes = compute_hashes(tmp_path)
if expected_sha1 and hashes["sha1"].lower() != expected_sha1.lower():
os.unlink(tmp_path)
return None
if expected_md5:
md5_list = [m.strip().lower() for m in expected_md5.split(",") if m.strip()]
if hashes["md5"].lower() not in md5_list:
os.unlink(tmp_path)
return None
os.replace(tmp_path, cached)
return cached