mirror of
https://github.com/rustwasm/wasm-bindgen.git
synced 2024-11-28 05:52:21 +03:00
c0cad447c1
This commit starts wasm-bindgen down the path of supporting closures. We discussed this at the recent Rust All-Hands but I ended up needing to pretty significantly scale back the ambitions of what closures are supported. This commit is just the initial support and provides only a small amount of support but will hopefully provide a good basis for future implementations. Specifically this commit adds support for passing `&Fn(...)` to an *imported function*, but nothing elese. The `&Fn` type can have any lifetime and the JS object is invalidated as soon as the import returns. The arguments and return value of `Fn` must currently implement the `WasmAbi` trait, aka they can't require any conversions like strings/types/etc. I'd like to soon expand this to `&mut FnMut` as well as `'static` closures that can be passed around for a long time in JS, but for now I'm putting that off until later. I'm not currently sure how to implement richer argument types, but hopefully that can be figured out at some point!
91 lines
2.1 KiB
Rust
91 lines
2.1 KiB
Rust
extern crate test_support;
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#[test]
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fn works() {
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test_support::project()
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.file("src/lib.rs", r#"
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#![feature(proc_macro, wasm_custom_section, wasm_import_module)]
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extern crate wasm_bindgen;
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use std::cell::Cell;
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use wasm_bindgen::prelude::*;
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#[wasm_bindgen(module = "./test")]
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extern {
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fn call(a: &Fn());
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fn thread(a: &Fn(u32) -> u32) -> u32;
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}
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#[wasm_bindgen]
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pub fn run() {
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let a = Cell::new(false);
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call(&|| a.set(true));
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assert!(a.get());
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assert_eq!(thread(&|a| a + 1), 3);
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}
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"#)
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.file("test.ts", r#"
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import { run } from "./out";
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export function call(a: any) {
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a();
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}
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export function thread(a: any) {
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return a(2);
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}
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export function test() {
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run();
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}
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"#)
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.test();
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}
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#[test]
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fn cannot_reuse() {
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test_support::project()
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.file("src/lib.rs", r#"
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#![feature(proc_macro, wasm_custom_section, wasm_import_module)]
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extern crate wasm_bindgen;
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use std::cell::Cell;
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use wasm_bindgen::prelude::*;
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#[wasm_bindgen(module = "./test")]
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extern {
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fn call(a: &Fn());
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#[wasm_bindgen(catch)]
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fn call_again() -> Result<(), JsValue>;
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}
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#[wasm_bindgen]
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pub fn run() {
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call(&|| {});
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assert!(call_again().is_err());
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}
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"#)
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.file("test.ts", r#"
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import { run } from "./out";
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let CACHE: any = null;
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export function call(a: any) {
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CACHE = a;
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}
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export function call_again() {
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CACHE();
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}
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export function test() {
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run();
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}
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"#)
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.test();
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}
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