auto_future/
auto_future.rs

1use ::std::fmt::Debug;
2use ::std::fmt::Formatter;
3use ::std::fmt::Result as FmtResult;
4use ::std::future::Future;
5use ::std::pin::Pin;
6use ::std::task::Context;
7use ::std::task::Poll;
8
9pub struct AutoFuture<T> {
10    inner: Pin<Box<dyn Future<Output = T>>>,
11    is_done: bool,
12}
13
14impl<T> AutoFuture<T> {
15    pub fn new<F>(raw_future: F) -> Self
16    where
17        F: Future<Output = T> + 'static,
18    {
19        Self {
20            inner: Box::pin(raw_future),
21            is_done: false,
22        }
23    }
24}
25
26impl<T> Future for AutoFuture<T> {
27    type Output = T;
28
29    fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
30        if self.is_done {
31            panic!("Polling future when this is already completed");
32        }
33
34        let inner_poll = self.inner.as_mut().poll(cx);
35        match inner_poll {
36            Poll::Pending => Poll::Pending,
37            Poll::Ready(inner_result) => {
38                self.is_done = true;
39                Poll::Ready(inner_result)
40            }
41        }
42    }
43}
44
45impl<T> Debug for AutoFuture<T> {
46    fn fmt(&self, f: &mut Formatter<'_>) -> FmtResult {
47        write!(
48            f,
49            "AutoFuture {{ inner: Pin<Box<dyn Future<Output = T>>>, is_dome: {:?} }}",
50            self.is_done
51        )
52    }
53}
auto_future/auto_future.rs

auto_future/
auto_future.rs
