Crate as_ffi_bindings

Expand description

The current module give a free access to an helper. With the goal of providing an helper to read and write basic pointers in a WebAssembly script builded from the AssemblyScript compiler.

Thanks to wasmer and the AssemblyScript Runtime, we can provide functions like alloc, read and write to interact with a given webassembly instance.

§Helpers

For the moment this crate implement helpers for the ArrayBuffer and for strings. Historically the ArrayBuffer is less tested than the string. But the both allow you to interact with a wasmer instance.

let wasm_bytes = include_bytes!(concat!(
env!("CARGO_MANIFEST_DIR"),
"/tests/runtime_exported.wat"
));
let store = Store::default();
let module = Module::new(&store, wasm_bytes)?;

let import_object = imports! {
"env" => {
    "abort" => Function::new_native_with_env(&store, Env::default(), abort),
},
};

let instance = Instance::new(&module, &import_object)?;
let memory = instance.exports.get_memory("memory").expect("get memory");

let mut env = Env::default();
env.init(&instance)?;

let get_string = instance
.exports
.get_native_function::<(), StringPtr>("getString")?;

let str_ptr = get_string.call()?;
let string = str_ptr.read(memory)?;

assert_eq!(string, "hello test");

let str_ptr_2 = StringPtr::alloc(&"hello return".to_string(), &env)?;
let string = str_ptr_2.read(memory)?;
assert_eq!(string, "hello return");