wasi 0.12.1+wasi-0.2.0

<div align="center">
  <h1><code>wasi</code></h1>

<strong>A <a href="https://bytecodealliance.org/">Bytecode Alliance</a> project</strong>

  <p>
    <strong>WASI API Bindings for Rust</strong>
  </p>

  <p>
    <a href="https://crates.io/crates/wasi"><img src="https://img.shields.io/crates/v/wasi.svg?style=flat-square" alt="Crates.io version" /></a>
    <a href="https://crates.io/crates/wasi"><img src="https://img.shields.io/crates/d/wasi.svg?style=flat-square" alt="Download" /></a>
    <a href="https://docs.rs/wasi/"><img src="https://img.shields.io/badge/docs-latest-blue.svg?style=flat-square" alt="docs.rs docs" /></a>
  </p>
</div>

This crate contains bindings for [WASI](https://github.com/WebAssembly/WASI)
APIs for the worlds:

* [`wasi:cli/command`]
* [`wasi:http/proxy`]

This crate is procedurally generated from [WIT] files using [`wit-bindgen`].

[`wasi:cli/command`]: https://github.com/WebAssembly/wasi-cli
[`wasi:http/proxy`]: https://github.com/WebAssembly/wasi-http
[WIT]: https://component-model.bytecodealliance.org/design/wit.html
[`wit-bindgen`]: https://github.com/bytecodealliance/wit-bindgen
[components]: https://component-model.bytecodealliance.org/
[`wasm-tools`]: https://github.com/bytecodealliance/wasm-tools

# Usage

First you can depend on this crate via `Cargo.toml`:

```toml
[dependencies]
wasi = "0.12.0"
```

Next you can use the APIs in the root of the module like so:

```rust
fn main() {
    let stdout = wasi::cli::stdout::get_stdout();
    stdout.blocking_write_and_flush(b"Hello, world!\n").unwrap();
}
```

This crate is intended to target [components] but today you need to go through
the intermediate build step of a core WebAssembly module using the `wasm32-wasi`
target:

```
$ cargo build --target wasm32-wasi
```

Next you'll want an "adapter" to convert the Rust standard library's usage of
`wasi_snapshot_preview1` to the component model. An example adapter can be found
from [Wasmtime's release page](https://github.com/bytecodealliance/wasmtime/releases/download/v17.0.0/wasi_snapshot_preview1.command.wasm).

```
$ curl -LO https://github.com/bytecodealliance/wasmtime/releases/download/v17.0.0/wasi_snapshot_preview1.command.wasm
```

Next to create a component you'll use the [`wasm-tools`] CLI to create a
component:

```
$ cargo install wasm-tools
$ wasm-tools component new target/wasm32-wasi/debug/foo.wasm \
    --adapt ./wasi_snapshot_preview1.command.wasm \
    -o component.wasm
```

And finally the component can be run by a runtime that has Component Model
support, such as [Wasmtime]:

```
$ wasmtime run component.wasm
Hello, world!
```

[Wasmtime]: https://github.com/bytecodealliance/wasmtime

# Development

The bulk of the `wasi` crate is generated by the [`wit-bindgen`] tool. The
`src/bindings.rs` file can be regenerated with:

```
$ ./ci/regenerate.sh
```

WASI definitions are located in the `wit` directory of this repository.
Currently they're copied from upstream repositories but are hoped to be better
managed in the future.

# License

This project is triple licenced under the Apache 2/ Apache 2 with LLVM exceptions/ MIT licences. The reasoning for this is:
- Apache 2/ MIT is common in the rust ecosystem.
- Apache 2/ MIT is used in the rust standard library, and some of this code may be migrated there.
- Some of this code may be used in compiler output, and the Apache 2 with LLVM exceptions licence is useful for this.

For more details see 
- [Apache 2 Licence](LICENSE-APACHE)
- [Apache 2 Licence with LLVM exceptions](LICENSE-Apache-2.0_WITH_LLVM-exception)
- [MIT Licence](LICENSE-MIT)

### Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted
for inclusion in this project by you, as defined in the Apache 2/ Apache 2 with LLVM exceptions/ MIT licenses,
shall be licensed as above, without any additional terms or conditions.