mckero
19ca5205fb
Two races shared the same cause: pushSamples runs on the audio capture thread
while clear() runs on the Compose main thread.
1. Lost redraw notifications
Both paths did `_revision.value += 1`. That expands to get -> add -> set and is
not atomic. A controlled two-thread probe (20k increments each, five runs)
lost up to 6,402 increments / 16%; using StateFlow.update lost zero. Since
revision is the Canvas's only redraw signal, every lost update can leave the
waterfall showing stale rows. If both writes land on the same number, StateFlow
sees no value change and notifies nobody.
Use `_revision.update { it + 1 }` in both paths.
2. Clear resurrected pre-clear audio
pushSamples copies pending audio under the lock, deliberately performs FFT
outside it, then reacquires the lock to append rows. The exact interleaving:
audio thread: take old audio, start FFT
main thread: user taps Clear -> rows/pending empty
audio thread: old FFT completes -> appends old rows again
The display becomes empty then immediately redraws the audio the user cleared.
A deterministic thread probe reproduced old rows after clear. Add a generation
counter protected by the same lock: pushSamples records it before FFT and drops
the computed rows when clear incremented it meanwhile. Fixed probe remains empty.
Verification: :feature:cw:compileReleaseKotlin + full :core:domain:test BUILD
SUCCESSFUL; grep confirms no non-atomic revision increments remain.
Look4Sat: Satellite tracker
Radio satellite tracker and pass predictor for Android, inspired by Gpredict
Track satellite passes with ease!
Thanks to Celestrak and SatNOGS you have access to over 9000 active satellites.
You can search the entire database by NORAD Catalog Number or the satellite's name.
Orbital positions and passes are calculated relative to your location.
To get reliable data make sure to set the station position via the app Settings.
The application is built using Kotlin, Coroutines, Jetpack Compose and Navigation.
It is now and always will be completely ad-free and open-source.
Main features:
- Predicting satellite positions and passes for up to 10 days
- Showing the list of currently active and upcoming satellite passes
- Showing the active pass progress, polar trajectory and transceivers info
- Showing the satellite positional data, footprint and ground track on the map
- Custom TLE satellite data import is available via Three Line Element .txt files
- Offline first: calculations are made offline. Weekly TLE data update is recommended.
License
The Look4Sat application code is licensed under the GNU General Public License v3.0.
The CW decoder in feature/cw bundles the DeepCW
neural decoding model, licensed under the GNU Affero General Public License v3.0 only
(AGPL-3.0-only). Because the combined work incorporates an AGPL-3.0 component, the
combined work is distributed under the
GNU Affero General Public License v3.0 — GPL-3.0 Section 13 permits the
combination, and AGPL-3.0 Section 13 applies to the combined work as a whole.
Model provenance and attribution are documented in
feature/cw/licenses/NOTICE.md; the original GPL-3.0
text is preserved at feature/cw/licenses/Look4Sat-GPL-3.0.txt. The CW model runs
locally on-device and does not provide services over a network.