Compressing clusters with zstd is the slow part of packing a large
mirror. When a mirror is re-packed after a small change, most clusters
are byte-identical and there is no reason to compress them again.
pack --incremental keeps a content-addressed cache of compressed
clusters in a sidecar next to the output. On the next pack, a cluster
whose uncompressed bytes match the cache is served from it instead of
being recompressed; only new or changed clusters go through zstd. A
cache hit returns exactly what a fresh compression would, so the archive
stays deterministic and byte-identical to a cold pack.
The zim writer gains a settable cluster compressor so the cache can hook
in without changing the format. The cache only writes back the clusters
it touched this run, so clusters that left the mirror drop out and it
cannot grow without bound.
Wrapping a packed viewer in a .app or .AppImage was its own --format app
value, parallel to zim and binary. But an app is really just the binary
format with a bundle around it, so a separate format meant duplicating the
base/icon handling and made the three formats feel like an awkward choice.
Turn it into a --app flag that builds on the binary format. It composes
with --base (including a webview base) and --icon, while --format stays
zim or binary. The bundle builders are unchanged; only the CLI surface
moves.
The new format dispatches on the base's target OS: a .app on macOS, an .AppDir
(plus an .AppImage when appimagetool is present) on Linux, and a friendly redirect
to --format binary on Windows, where the .exe is already the app. The icon comes
from the mirror's favicon by default and can be overridden with --icon.
Packing with --base pointed at a kage built for another OS used to guess the
target from the file name: a base ending in .exe meant Windows, anything else
meant the host. That misfired in both directions. A Windows base without the
.exe suffix produced a viewer with no extension that will not run on Windows,
and an --out name that dropped .exe made the run hint print a macOS quarantine
note for a Windows file.
Sniff the base's executable header (ELF, PE, Mach-O) instead, so the target OS
comes from the bytes rather than the name. A Windows viewer now always gets a
.exe suffix, and the run hint names the real target and only mentions Gatekeeper
for actual macOS viewers.
pack packs a mirror to a zim file or a runnable viewer, accepting a bare
host that it resolves against the default output directory. open serves a
zim over http like serve does for a folder. Execute checks for an appended
archive first, so a packed kage runs as an offline viewer on an ephemeral
port and ignores its arguments.
Tam Nguyen Duc