1use crate::async_iter::AsyncIterator;
2use crate::pin::Pin;
3use crate::task::{Context, Poll};
4
5/// An async iterator that was created from iterator.
6///
7/// This async iterator is created by the [`from_iter`] function.
8/// See it documentation for more.
9///
10/// [`from_iter`]: fn.from_iter.html
11#[unstable(feature = "async_iter_from_iter", issue = "81798")]
12#[derive(Clone, Debug)]
13pub struct FromIter<I> {
14 iter: I,
15}
16
17#[unstable(feature = "async_iter_from_iter", issue = "81798")]
18impl<I> Unpin for FromIter<I> {}
19
20/// Converts an iterator into an async iterator.
21#[unstable(feature = "async_iter_from_iter", issue = "81798")]
22pub fn from_iter<I: IntoIterator>(iter: I) -> FromIter<I::IntoIter> {
23 FromIter { iter: iter.into_iter() }
24}
25
26#[unstable(feature = "async_iter_from_iter", issue = "81798")]
27impl<I: Iterator> AsyncIterator for FromIter<I> {
28 type Item = I::Item;
29
30 fn poll_next(mut self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
31 Poll::Ready(self.iter.next())
32 }
33
34 fn size_hint(&self) -> (usize, Option<usize>) {
35 self.iter.size_hint()
36 }
37}
38