Any site could POST a form to the share target on load: with no clicks
the composer opened with its subject and file, and autosave stored a
real draft on the server 2 seconds later. The worker can't see where a
POST came from, and Chromium's link capturing accepts form submissions,
so an installed-app window proves nothing either.
- every share landing now asks first, in every window and browser; a
text landing address gets the same question. Nothing goes up before
the answer.
- handed-in text and files are the composer's starting state: no
autosave, page-close save or sign-out flush before the first real
edit.
- the worker ignores frames, keeps at most 5 entries and 100 MB for 15
minutes, sweeps on activate, on each share and from a page timer,
and seals what it keeps with a key passed in the landing fragment.
Offline wipes clear it too.
- the server fallback uses the fragment and caps by encoded length:
3000 Japanese characters made a 27 KB `Location` and a 431.
- a second compose handoff waits until the composer closes, also one
set aside by reading a message, where it used to replace the first.
- a launch leaving the mail page saves what was just typed first.
- an expired handoff or a missing stored file now says so; shares get
the control-character stripping and limits of `parseMailto`.
Existing tests changed because the landing moved from the query to the
fragment, stored entries gained a sealed part, and a share now asks
first.
Linus Rath
f716ea66ee