async-std/src/stream/from_iter.rs
2019-11-01 21:18:43 +09:00

50 lines
1.2 KiB
Rust

use std::pin::Pin;
use pin_project_lite::pin_project;
use crate::stream::Stream;
use crate::task::{Context, Poll};
pin_project! {
/// A stream that created from iterator
///
/// This stream is created by the [`from_iter`] function.
/// See it documentation for more.
///
/// [`from_iter`]: fn.from_iter.html
#[derive(Debug)]
pub struct FromIter<I> {
iter: I,
}
}
/// # Examples
///```
/// # async_std::task::block_on(async {
/// #
/// use async_std::prelude::*;
/// use async_std::stream;
///
/// let mut s = stream::from_iter(vec![0, 1, 2, 3]);
///
/// assert_eq!(s.next().await, Some(0));
/// assert_eq!(s.next().await, Some(1));
/// assert_eq!(s.next().await, Some(2));
/// assert_eq!(s.next().await, Some(3));
/// assert_eq!(s.next().await, None);
/// #
/// # })
///````
pub fn from_iter<I: IntoIterator>(iter: I) -> FromIter<<I as std::iter::IntoIterator>::IntoIter> {
FromIter {
iter: iter.into_iter(),
}
}
impl<I: Iterator> Stream for FromIter<I> {
type Item = I::Item;
fn poll_next(mut self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
Poll::Ready(self.iter.next())
}
}