straw/rust/README.md
Kayos 7ff5ac79e5 v0.1.0-U (vc=8): Phase U-1 + U-2 — Rust core + rustypipe search
NewPipeExtractor (Java) → strawcore (Rust) migration begins. Phase U:
- U-1: Rust toolchain + UniFFI smoke test
- U-2: rustypipe search via uniffi suspend fun, SearchViewModel swapped

What landed:
- rust/strawcore — UniFFI-exported Rust crate using proc-macros.
  Builds for arm64-v8a + armeabi-v7a + x86 + x86_64 via cargo-ndk.
  Tokio multi-thread runtime singleton drives rustypipe's async API.
- strawApp/build.gradle.kts — cargoBuildHost + cargoBuild + uniffiBindgen
  Gradle Exec tasks chained into the Android build. Generated Kotlin
  bindings land in src/main/java/uniffi/strawcore/ (gitignored).
- SearchViewModel.kt — calls uniffi.strawcore.search(query) directly.
  NewPipeExtractor still in deps for VideoDetail/Player/Channel paths;
  those move to Rust in U-3 / U-4.
- Build chain quirks beat:
  * cargo absolute path in Exec tasks (PATH wasn't propagating)
  * uniffi-bindgen needs UNSTRIPPED host .so — separate cargoBuildHost
    builds a debug-profile host lib to read metadata from
  * rustypipe rustls-tls-webpki-roots avoids the openssl-sys
    cross-compile tarpit
  * rquickjs-sys 'bindgen' feature opted in (no prebuilt Android
    bindings ship; crafting-table has libclang 14)
- crafting-table runtime install (until Dockerfile catches up):
  rustup + 4 Android targets + cargo-ndk + NDK r27c. Persists in
  /caches/cargo + /caches/android-sdk via the volume mount.

APK size: 22MB (U-1) → 37MB (U-2). libstrawcore.so 3-5MB per ABI carries
rustypipe + reqwest + tokio + rustls + rquickjs. NewPipeExtractor still
in for now (still drives detail + player + channel + feed), so the
Java half is doubled up. U-5 removes it.
2026-05-24 08:36:50 -07:00

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# `rust/` — strawcore: Rust YouTube core for Straw
Phase **U-** of the Straw build. Goal: replace the Java NewPipeExtractor
dependency with a Rust core (rustypipe + tokio + reqwest), exposed to the
Kotlin/Compose UI via [UniFFI](https://mozilla.github.io/uniffi-rs/).
Compose UI stays in Kotlin — only the YouTube/Innertube fetching layer
moves to Rust.
## Phases
| Phase | What |
|---|---|
| **U-1** | Toolchain + UniFFI smoke test (`hello_from_rust`) round-tripping through JNA. No real APIs yet. |
| **U-2** | rustypipe search. `SearchViewModel` calls the Rust core. |
| **U-3** | rustypipe streamInfo + streams. `VideoDetailViewModel` + `PlayerViewModel` use it. |
| **U-4** | rustypipe channel + tabs. `ChannelViewModel` + `SubscriptionFeedViewModel`. |
| **U-5** | Rip NewPipeExtractor Java dep. Measure APK + cold-fetch latency before/after. |
| **U-6** *(stretch)* | SponsorBlock + RYD HTTP through reqwest + tokio in the same lib. |
## Build chain
```
crafting-table
├── rustup stable (target add: aarch64-linux-android, armv7-linux-androideabi,
│ x86_64-linux-android, i686-linux-android)
├── cargo-ndk (cross-compile helper)
├── android-sdk (ANDROID_HOME, sdkmanager, build-tools, platforms)
└── android-ndk (ANDROID_NDK_HOME, r27c LTS at /caches/android-sdk/ndk/...)
Gradle (strawApp/build.gradle.kts)
├── cargoBuild Exec task → cargo ndk -t <abi>... -o jniLibs/ build --release
├── uniffiBindgen Exec task → cargo run --bin uniffi-bindgen ... --library libstrawcore.so
└── source-set wiring generated Kotlin lands in strawApp/src/main/java/uniffi/strawcore/
Runtime (StrawApp.onCreate)
├── System.loadLibrary("strawcore")
└── uniffi.strawcore.initLogging()
```
## Why UniFFI (and not raw JNI / JNA bindings)
- Hand-written JNI: tedious, error-prone, every type change is two files
(Kotlin + Rust) that must stay in sync.
- Raw JNA: better, but you still hand-write the Kotlin side and worry about
string ownership.
- UniFFI: write Rust, annotate with `#[uniffi::export]`, get a Kotlin shim
generated. Strings, structs, enums, Result types, `async` functions all
cross the boundary transparently. The runtime is JNA under the hood.
## When in doubt
- `cargo check -p strawcore --target aarch64-linux-android` — fast iteration.
- `cargo run --bin uniffi-bindgen -- generate ...` — regenerate Kotlin bindings.
- `adb logcat -s strawcore` — Rust `log::info!()` lands here.
- `aapt dump badging strawApp/build/outputs/apk/debug/strawApp-debug.apk`
inspect what ABIs/native-libs the APK carries.