worker/
send.rs

1//! This module provides utilities for working with JavaScript types
2//! which do not implement `Send`, in contexts where `Send` is required.
3//! Workers is guaranteed to be single-threaded, so it is safe to
4//! wrap any type with `Send` and `Sync` traits.
5
6use futures_util::future::Future;
7use pin_project::pin_project;
8use std::fmt::Debug;
9use std::fmt::Display;
10use std::pin::Pin;
11use std::task::Context;
12use std::task::Poll;
13
14#[derive(Debug)]
15#[pin_project]
16/// Wrap any future to make it `Send`.
17///
18/// ```rust
19/// let fut = SendFuture::new(JsFuture::from(promise));
20/// fut.await
21/// ```
22pub struct SendFuture<F> {
23    #[pin]
24    inner: F,
25}
26
27impl<F> SendFuture<F> {
28    pub fn new(inner: F) -> Self {
29        Self { inner }
30    }
31}
32
33unsafe impl<F> Send for SendFuture<F> {}
34unsafe impl<F> Sync for SendFuture<F> {}
35
36impl<F: Future> Future for SendFuture<F> {
37    type Output = F::Output;
38
39    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
40        let this = self.project();
41        this.inner.poll(cx)
42    }
43}
44
45/// Trait for SendFuture. Implemented for any type that implements Future.
46///
47/// ```rust
48/// let fut = JsFuture::from(promise).into_send();
49/// fut.await
50/// ```
51pub trait IntoSendFuture {
52    type Output;
53    fn into_send(self) -> SendFuture<Self>
54    where
55        Self: Sized;
56}
57
58impl<F, T> IntoSendFuture for F
59where
60    F: Future<Output = T>,
61{
62    type Output = T;
63    fn into_send(self) -> SendFuture<Self> {
64        SendFuture::new(self)
65    }
66}
67
68/// Wrap any type to make it `Send`.
69///
70/// ```rust
71/// // js_sys::Promise is !Send
72/// let send_promise = SendWrapper::new(promise);
73/// ```
74pub struct SendWrapper<T>(pub T);
75
76unsafe impl<T> Send for SendWrapper<T> {}
77unsafe impl<T> Sync for SendWrapper<T> {}
78
79impl<T> SendWrapper<T> {
80    pub fn new(inner: T) -> Self {
81        Self(inner)
82    }
83}
84
85impl<T> std::ops::Deref for SendWrapper<T> {
86    type Target = T;
87
88    fn deref(&self) -> &Self::Target {
89        &self.0
90    }
91}
92
93impl<T> std::ops::DerefMut for SendWrapper<T> {
94    fn deref_mut(&mut self) -> &mut Self::Target {
95        &mut self.0
96    }
97}
98
99impl<T: Debug> Debug for SendWrapper<T> {
100    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
101        write!(f, "SendWrapper({:?})", self.0)
102    }
103}
104
105impl<T: Clone> Clone for SendWrapper<T> {
106    fn clone(&self) -> Self {
107        Self(self.0.clone())
108    }
109}
110
111impl<T: Default> Default for SendWrapper<T> {
112    fn default() -> Self {
113        Self(T::default())
114    }
115}
116
117impl<T: Display> Display for SendWrapper<T> {
118    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
119        write!(f, "SendWrapper({})", self.0)
120    }
121}
worker/send.rs

worker/
send.rs
