2ff2e2505a
This commit fixes an erroneous use-after-free which can happen in erroneous situations in JS. It's intended that if you invoke a closure after its environment has been destroyed that you'll immediately get an error from Rust saying so. The JS binding generation for mutable closures, however, accidentally did not protect against this. Each closure has an internal reference count which is incremented while being invoked and decremented when the invocation finishes and also when the `Closure` in Rust is dropped. That means there's two branches where the reference count reaches zero and the internal pointer stored in JS needs to be set to zero. Only one, however, actually set the pointer to zero! This means that if a closure was destroyed while it was being invoked it would not correctly set its internal pointer to zero. A further invocation of the closure would then pass as seemingly valid pointer into Rust, causing a use-after-free. A test isn't included here specifically for this because our CI has started failing left-and-right over this test, so this commit will hopefully just make our CI green!
wasm-bindgen
Facilitating high-level interactions between wasm modules and JavaScript.
Import JavaScript things into Rust and export Rust things to JavaScript.
extern crate wasm_bindgen;
use wasm_bindgen::prelude::*;
// Import the `window.alert` function from the Web.
#[wasm_bindgen]
extern "C" {
fn alert(s: &str);
}
// Export a `greet` function from Rust to JavaScript, that alerts a
// hello message.
#[wasm_bindgen]
pub fn greet(name: &str) {
alert(&format!("Hello, {}!", name));
}
Use exported Rust things from JavaScript with ECMAScript modules!
import { greet } from "./hello_world";
greet("World!");
Features
-
Lightweight. Only pay for what you use.
wasm-bindgenonly generates bindings and glue for the JavaScript imports you actually use and Rust functionality that you export. For example, importing and using thedocument.querySelectormethod doesn't causeNode.prototype.appendChildorwindow.alertto be included in the bindings as well. -
ECMAScript modules. Just import WebAssembly modules the same way you would import JavaScript modules. Future compatible with WebAssembly modules and ECMAScript modules integration.
-
Designed with the "host bindings" proposal in mind. Eventually, there won't be any JavaScript shims between Rust-generated wasm functions and native DOM methods. Because the wasm functions are statically type checked, some of those native methods' dynamic type checks should become unnecessary, promising to unlock even-faster-than-JavaScript DOM access.
Guide
📚 Read the wasm-bindgen guide here! 📚
You can find general documentation about Rust and WebAssembly here.
API Docs
License
This project is licensed under either of
- Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
- MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)
at your option.
Contribution
See the "Contributing" section of the guide for information on
hacking on wasm-bindgen!
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in this project by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.