Axion Engine

This library is used to get a good interopability between Kotlin and WebAssembly (especially with Rust but I think you can port the wasm_utils.rs to other languages).

Features

• Loading WASM modules into Kotlin
• Calling WASM exports function with Kotlin types
• WASM Imports for calling Kotlin from WASM
• Support for all primitive types + structures
• Cross platform

Usage/Examples

Rust:

mod wasm_utils;

use wasm_utils::*;

extern "C" {
    pub fn kotlin_print(str: *mut String);
}

#[no_mangle]
pub unsafe fn test(x: [i64; 4]) -> f32 {
    kotlin_print(into_mut_ptr("Hello from Rust !".to_string()));
    x.len() as f32
}

Kotlin:

class KotlinPrintImport : WasmImport(
    "kotlin_print",
    EnumWasmType.VOID,             //return type
    arrayOf(EnumWasmType.STRING),  //args types
    { axionEngine, args ->         //callback
        val firstArgument = args[0].value as String

        println(firstArgument)

        null                        //for void functions, returning null is good
    }
)

fun main() {
    val wasmBin = File("rust.wasm").readBytes()

    val axionEngine = AxionEngine(wasmBin,
        KotlinPrintImport(),
        //...  (add all your imports)
    )

    val callResult = axionEngine.callExport<FloatWasmType>  //for void functions, do not put a type
        (
        "test",  //function name
        listOf(1L, 2L, 3L, 4L).toWasmType(axionEngine),
        //...   (add all your arguments)
        )

    println(callResult.value)
}

(see more examples in the kotlin test directory and in the rust example)

Authors

• @NOctu1412

Thanks to

• @wasmerio for the wasmer and wasmer-java librairies !

• @beaclnd92 for his wasmer-java pull request