wasmtime_wasi

Module bindings

source
Expand description

Auto-generated bindings for WASI interfaces.

This module contains the output of the bindgen! macro when run over the wasi:cli/command world. That means this module has all the generated types for WASI for all of its base interfaces used by the CLI world. This module itself by default contains bindings for async-related traits. The sync module contains bindings for a non-async version of types.

§Examples

If you have a WIT world which refers to WASI interfaces you probably want to use this crate’s bindings rather than generate fresh bindings. That can be done using the with option to bindgen!:

use wasmtime_wasi::{WasiCtx, ResourceTable, WasiView};
use wasmtime::{Result, Engine, Config};
use wasmtime::component::Linker;

wasmtime::component::bindgen!({
    inline: "
        package example:wasi;

        // An example of extending the `wasi:cli/command` world with a
        // custom host interface.
        world my-world {
            include wasi:cli/command@0.2.2;

            import custom-host;
        }

        interface custom-host {
            my-custom-function: func();
        }
    ",
    path: "wit",
    with: {
        "wasi": wasmtime_wasi::bindings,
    },
    async: true,
});

struct MyState {
    table: ResourceTable,
    ctx: WasiCtx,
}

#[async_trait::async_trait]
impl example::wasi::custom_host::Host for MyState {
    async fn my_custom_function(&mut self) {
        // ..
    }
}

impl WasiView for MyState {
    fn table(&mut self) -> &mut ResourceTable { &mut self.table }
    fn ctx(&mut self) -> &mut WasiCtx { &mut self.ctx }
}

fn main() -> Result<()> {
    let mut config = Config::default();
    config.async_support(true);
    let engine = Engine::new(&config)?;
    let mut linker: Linker<MyState> = Linker::new(&engine);
    wasmtime_wasi::add_to_linker_async(&mut linker)?;
    example::wasi::custom_host::add_to_linker(&mut linker, |state| state)?;

    // .. use `Linker` to instantiate component ...

    Ok(())
}

Modules§

Structs§