FR-PLAT-AND-6 asks for two things this app did neither of: be a receiver for
image view and share intents, and share exported results out through a
FileProvider. The manifest declared one activity with one MAIN/LAUNCHER filter,
so nothing on the device ever offered DarkRoom for a photograph, and there was
no route out at all — Android has refused file:// URIs between apps since API
24, and a content:// URI needs a provider to be behind it.
Inbound. Three filters now: VIEW for a gallery or a file manager, SEND and
SEND_MULTIPLE for the share sheet, all on image/*. `android_main` reads the
launch Intent before it gives `app` away to Slint, and what comes back is
passed to `dr_ui::run` exactly as argv is on the desktop — `startup_action`
already treats a non-empty list as "the user asked for these specifically",
which is what a share is.
The URIs are copied into the cache before the viewer opens, and that cost is
real: a shared raw file is written once, in full, on the startup path. A
content:// URI is a handle into another app's provider, not a path, and the
decoders take paths; the alternative is teaching the whole read path about
URIs, which is FR-PLAT-AND-1's SAF connector and is not built.
Outbound. ExportProvider serves one directory — getFilesDir(), which is the
same path `internal_data_path` gives the Rust side — and refuses everything
else by canonicalising the request and checking it is inside that root, so
`../` and a planted symlink fail the same test. Not AndroidX's FileProvider,
because AndroidX is a Maven artefact and this build has no resolver; what it
does is a hundred lines and they are here.
The share half has no caller. The provider, the URI grant and the chooser are
all in place, but the control that would invoke them belongs in `ui/dr-ui`, and
wiring it needs an `AndroidApp` the interface can reach. It is documented as
unwired and deliberately not tagged as covering the requirement.
`launchMode="singleTask"` comes with the filters and is not decoration: another
app can now launch this activity while it is running, and the default mode
answers that by creating a second NativeActivity in the same process — a second
android_main, a second Slint backend, a second wgpu device. The cost of the
fix is stated in the manifest: a share arriving while DarkRoom is already open
brings it forward without opening the image, because onNewIntent has no route
through android-activity's event stream.
The Java is Java because Android constructs it: a ContentProvider is
instantiated by the system from its manifest entry, and getIntent() exists only
on an activity object. Both directions live there rather than in JNI so that
what crosses the boundary is two method signatures instead of forty, each of
which is a string checked at run time and nowhere else.
What a test can hold: the declarations. Nothing about an Intent or a
ContentProvider is reachable from `cargo test`, but an intent filter that is
deleted takes the app out of every "open with" menu silently, and an authority
that stops matching its class raises a SecurityException inside somebody else's
app. The tests in lib.rs read the manifest and ExportProvider.java through
`include_str!` and hold both to that, on the host, which is the only place in
the workspace that looks at either file from Rust.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
dtourolleandClaude Opus 5
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