Android WASI host integration for MoonBit guests.

moonbit

wasm

wasi

android

usb

aoa

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Author

Nanaloveyuki

Version

0.1.0

License

MIT

Repository

github.com/Nanaloveyuki/wasee-moon

Last updated

22 hours ago

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Dependencies

Nanaloveyuki/madk0.1.0

#wasee-moon

wasee-moon is the Android host companion for running MoonBit Wasm guests with a bounded USB capability. It embeds a WASI Preview 1 runtime in an Android app and keeps Android USB objects on the host side.

#Current slice

The repository currently provides:

a MoonBit guest compiled to core Wasm;
an Android app embedding Chicory WASI Preview 1;
a reusable android/host library for Orbit and other Android Activities;
an Android UsbHost implementation backed by UsbManager;
an explicit USB allowlist and bounded transfer options;
a reusable bridge package implementing madk's UsbTransport over bounded core-Wasm imports;
guest-side madk.AoaSession negotiation and length-prefixed status/echo validation for allowlisted AOA devices;
a copy of the madk:aoa WIT contract.

The bridge is deliberately not presented as a Component Model binding. It is a bounded core-Wasm ABI that consumes Nanaloveyuki/madk@0.1.0 and keeps the portable AOA state machine in madk. Non-AOA devices use the descriptor smoke; AOA-vendor devices use madk.AoaSession and the fixture frame protocol. Generated WIT/component bindings remain a later ABI migration.

#Boundary

madk owns the portable AOA protocol state machine and transport contracts. This repository owns the Android runtime and host capability implementation. The Android host must not expose UsbDeviceConnection, Java objects, raw pointers, or unbounded filesystem/network capabilities to a guest.

The host flow is:

enumerate only configured USB allowlist entries;
request Android permission outside the guest;
open an approved device and retain the native Android connection privately;
translate bounded control and bulk operations to madk's UsbTransport;
after AOA start, wait for accessory re-enumeration and replace the connection behind the same guest handle;
close every guest-owned handle during teardown.

See docs/architecture.md for the split and docs/bridge-abi.md for the temporary core-Wasm ABI. The latest local hardware/runtime evidence is in docs/validation.md.

#Build

Requirements:

MoonBit 0.10.9+6e6c44045, selected by .moon-version;
JDK 17;
Android SDK platform 36 and build tools 37.0.0;
Android minSdk 26 for Chicory method-handle support;
Gradle 9.6.1 or a compatible Gradle installation;
an Android SDK platform-tools installation for device validation.

Build the guest:

moon check guest --target wasm --deny-warn
moon build guest --target wasm --release

Build the Android host. The Gradle buildGuestWasm task compiles and copies the guest into the app assets before preBuild:

cd android
gradle :app:assembleDebug --no-daemon

The host library is a separate Gradle module:

gradle :host:assembleRelease --no-daemon

Embedding applications use WaseeHostController from android/host. They retain ownership of Activity lifecycle and permission PendingIntent creation, while the library owns AndroidUsbHost, WasiGuestRunner, Chicory imports, bounded transfers, and handle cleanup.

The first build may need network access to resolve Android Gradle Plugin and Chicory artifacts from Maven Central.

#Runtime choice

The first Android slice uses com.dylibso.chicory:wasi:1.7.5, runtime:1.7.5, and wasm:1.7.5. Chicory is a pure JVM runtime, so this prototype does not require an NDK or architecture-specific JNI libraries. The Android host boundary is kept behind WasiGuestRunner; a future native runtime can replace that implementation without moving UsbManager logic into the guest-facing API.

#Validation

moon fmt --check
moon check bridge --target wasm --deny-warn
moon check guest --target wasm --deny-warn
moon check --target all --deny-warn
moon test --target all --deny-warn
moon build guest --target wasm --release
cd android
gradle :app:testDebugUnitTest --no-daemon
gradle :app:assembleDebug --no-daemon

USB/AOA validation requires a permitted physical data connection. It is separate from the Android APK build and can be performed after the device is available again. A mass-storage disk validates the descriptor path. AOA negotiation and fixture frames require an external AOA-capable device; the madk Android fixture is a device-side target, not an Android-host test source.

#License

MIT. See LICENSE.

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