3 releases
0.1.3 | Apr 8, 2021 |
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0.1.2 | Mar 1, 2021 |
0.1.1 | Jan 26, 2021 |
#1930 in Rust patterns
21KB
647 lines
uptown_funk is a crate that lets you elegantly define Wasm host functions that are compatible with both Wasmtime and Wasmer runtimes.
It consists of a macro and a few structs/traits that let you translate from Wasm primitive types to higher level Rust types, and back.
Lets look at an example of a host function definition using uptown_funk
:
#[host_functions(namespace = "wasi_snapshot_preview1")]
impl WasiState {
async fn fd_pread(&mut self, fd: u32, iovs: &mut [IoSliceMut<'_>], offset: Filesize) -> (Status, u32) {
// ...
}
// .. Other functions depending on the WasiState struct.
}
The host_function
macro lets us grab any host side struct and use it as state for the Wasm instances.
Instead of dealing with low level pointers + lengths passed from the WebAssembly guests, we can pretend
to receive higher level Rust type (e.g. &mut [IoSliceMut<'_>]
) and the macro is going to create
appropriate wrappers for us. And of course, it correctly works with async
functions on Lunatic.
Dependencies
~1.3–5.5MB
~108K SLoC