045d6a7310
* Remove the need for `HostRef<Store>` This commit goes through the public API of the `wasmtime` crate and removes the need for `HostRef<Store>`, as discussed in #708. This commit is accompanied with a few changes: * The `Store` type now also implements `Default`, creating a new `Engine` with default settings and returning that. * The `Store` type now implements `Clone`, and is documented as being a "cheap clone" aka being reference counted. As before there is no supported way to create a deep clone of a `Store`. * All APIs take/return `&Store` or `Store` instead of `HostRef<Store>`, and `HostRef<T>` is left as purely a detail of the C API. * The `global_exports` function is tagged as `#[doc(hidden)]` for now while we await its removal. * The `Store` type is not yet `Send` nor `Sync` due to the usage of `global_exports`, but it is intended to become so eventually. * Touch up comments on some examples * Run rustfmt
wasmtime-rust - Using WebAssembly from Rust
This crate is intended to be an example of how to load WebAssembly files from a
native Rust application. You can always use wasmtime and its family of crates
directly, but the purpose of this crate is to provide an ergonomic macro:
#[wasmtime_rust::wasmtime]
trait WasmMarkdown {
fn render(&mut self, input: &str) -> String;
}
fn main() -> anyhow::Result<()> {
let mut markdown = WasmMarkdown::load_file("markdown.wasm")?;
println!("{}", markdown.render("# Hello, Rust!"));
Ok(())
}
The wasmtime macro defined in the wasmtime-rust crate is placed on a trait
which includes the set of functionality which a wasm module should export. In
this case we're expecting one render function which takes and returns a
string.
The macro expands to a struct with all of the methods on the trait (they must
all be &mut self) and one function called load_file to actually instantiate
the module.
Note that this macro is still in early stages of development, so error messages aren't great yet and all functionality isn't supported yet.
Missing features
Currently if the wasm module imports any symbols outside of the WASI namespace the module will not load. It's intended that support for this will be added soon though!