emscripten-futures 0.5.0

A local async executor and awaitable Emscripten operations for Rust WebAssembly applications
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51

use futures::task::ArcWake;
use std::{cell::RefCell, sync::Arc, task::Wake};

mod local_pool;
pub use local_pool::*;

#[cfg(test)]
mod tests;

use crate::promise::Promise;

#[derive(Default)]
struct PromiseWaker {
    promise: RefCell<Promise<()>>,
}

unsafe impl Send for PromiseWaker {}
unsafe impl Sync for PromiseWaker {}

impl PromiseWaker {
    fn notify(&self) {
        let _ = self.promise.borrow().fulfill(());
    }

    fn wait(&self) {
        self.promise.borrow().wait();
        // A promise retains its result. Start a fresh notification cycle after
        // releasing both the result borrow and the borrow of the old promise.
        self.promise.replace(Promise::default());
    }

    fn woken(&self) -> bool {
        self.promise.borrow().is_resolved()
    }
}

impl Wake for PromiseWaker {
    fn wake(self: Arc<Self>) {
        self.notify();
    }

    fn wake_by_ref(self: &Arc<Self>) {
        self.notify();
    }
}

impl ArcWake for PromiseWaker {
    fn wake_by_ref(arc_self: &Arc<Self>) {
        arc_self.notify();
    }
}