Files
dusk/tools/asset/pack/__main__.py
T
YourWishesandClaude Sonnet 5 c8a6325615 Collapse dusk.dsk from two zip archives into one, all uncompressed
Bulk assets (mp3, png) are already compressed at the file level, so a
DEFLATE pass on top bought negligible space for real CPU cost. Packs
everything into a single ZIP_STORED archive instead, so every entry
(not just locale/*) gets the reliable repeated seeking/re-opening that
libzip only supports for uncompressed entries. Header shrinks from 32
to 16 bytes; version bumped to 2 so a stale pre-change dusk.dsk is
rejected and rebuilt rather than misread.

Co-Authored-By: Claude Sonnet 5 <[email protected]>
2026-09-09 10:17:34 -05:00

133 lines
4.3 KiB
Python

# Copyright (c) 2026 Dominic Masters
#
# This software is released under the MIT License.
# https://opensource.org/licenses/MIT
"""
Packs the assets directory into a dusk.dsk (DSK2) archive.
A small fixed header (magic/version/size/checksum) followed by a single
uncompressed (ZIP_STORED) zip archive of every asset. Uncompressed rather
than DEFLATEd because the bulk of what's packed (audio, images) is
already compressed at the file level, so a second, zip-level DEFLATE
pass buys negligible space back for real CPU cost, and it lets every
entry - not just a hand-picked subset - support the reliable repeated
seeking/re-opening (e.g. locale line-by-line reads, MP3 loop restarts)
that libzip only supports for uncompressed entries.
DSK2 format:
Bytes 0-3: "DSK2" (magic)
Bytes 4-7: uint32_t version = 2 (little-endian)
Bytes 8-11: uint32_t size (byte length of the zip archive that follows)
Bytes 12-15: uint32_t checksum (CRC32 of the zip archive that follows)
Bytes 16+: the zip archive itself
Usage:
python3 -m tools.asset.pack --input <assets_dir> --output <dusk.dsk>
Every file under <assets_dir> is added, using its path relative to
<assets_dir> as the zip entry name.
Called unconditionally on every CMake build (see the DUSK_ASSETS_BUILT
target) rather than gated behind file-level build-system dependencies -
CMake's CONFIGURE_DEPENDS glob only notices added/removed files on the
NEXT configure, so a plain custom_command DEPENDS list can miss edits to
existing files or lag a build behind on adds/removes. Instead this script
itself decides whether anything actually needs repacking: it writes a
manifest of every input file's (mtime, size) next to the output on each
successful pack, and skips the real work if a fresh manifest compares
equal to it and the output still exists. The manifest also carries the
format version, so a manifest written by an older version of this script
(a stale single/dual-archive dusk.dsk sitting from before a format
change) never compares equal and always triggers a fresh pack.
"""
import argparse
import json
import os
import struct
import zipfile
import zlib
import io
MAGIC = b'DSK2'
VERSION = 2
HEADER_FORMAT = '<4sIII'
HEADER_SIZE = struct.calcsize(HEADER_FORMAT)
def build_zip_blob(root, relative_paths):
buf = io.BytesIO()
with zipfile.ZipFile(buf, 'w', compression=zipfile.ZIP_STORED) as zf:
for relative_path in sorted(relative_paths):
zf.write(os.path.join(root, relative_path), arcname=relative_path)
return buf.getvalue()
def manifest_path(output_path):
return output_path + '.manifest.json'
def compute_manifest(input_dir, relative_paths):
entries = {}
for relative_path in relative_paths:
st = os.stat(os.path.join(input_dir, relative_path))
entries[relative_path] = [st.st_mtime_ns, st.st_size]
return {'version': VERSION, 'files': entries}
def load_manifest(path):
try:
with open(path, 'r', encoding='utf-8') as f:
return json.load(f)
except (OSError, ValueError):
return None
def pack(input_dir, output_path):
relative_paths = []
for dirpath, _dirnames, filenames in os.walk(input_dir):
for filename in filenames:
full_path = os.path.join(dirpath, filename)
relative_paths.append(
os.path.relpath(full_path, input_dir).replace(os.sep, '/')
)
manifest = compute_manifest(input_dir, relative_paths)
manifest_file = manifest_path(output_path)
if os.path.isfile(output_path) and load_manifest(manifest_file) == manifest:
print(f'{output_path} is up to date, skipping pack')
return
blob = build_zip_blob(input_dir, relative_paths)
header = struct.pack(
HEADER_FORMAT, MAGIC, VERSION, len(blob), zlib.crc32(blob) & 0xFFFFFFFF
)
with open(output_path, 'wb') as f:
f.write(header)
f.write(blob)
with open(manifest_file, 'w', encoding='utf-8') as f:
json.dump(manifest, f)
print(
f'Wrote {output_path}: {len(relative_paths)} file(s) '
f'({len(blob)} bytes), {len(header) + len(blob)} bytes total'
)
def main():
parser = argparse.ArgumentParser(
description='Pack the assets directory into a dusk.dsk (DSK2) archive.'
)
parser.add_argument('--input', required=True, help='Assets directory to pack')
parser.add_argument('--output', required=True, help='Path to write dusk.dsk to')
args = parser.parse_args()
pack(args.input, args.output)
if __name__ == '__main__':
main()