1  use crate::lib::future::Future;
2  use crate::lib::marker::Unpin;
3  use crate::lib::pin::Pin;
4  use crate::lib::task::{Context, Poll};
5  
6  // Replace usage of this with std::future::poll_fn once it stabilizes
7  pub struct PollFn<F> {
8      f: F,
9  }
10  
11  impl<F> Unpin for PollFn<F> {}
12  
poll_fn<T, F>(f: F) -> PollFn<F> where F: FnMut(&mut Context<'_>) -> Poll<T>,13  pub fn poll_fn<T, F>(f: F) -> PollFn<F>
14  where
15      F: FnMut(&mut Context<'_>) -> Poll<T>,
16  {
17      PollFn { f }
18  }
19  
20  impl<T, F> Future for PollFn<F>
21  where
22      F: FnMut(&mut Context<'_>) -> Poll<T>,
23  {
24      type Output = T;
25  
poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<T>26      fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<T> {
27          (&mut self.f)(cx)
28      }
29  }
30