1 use crate::io::{AsyncSeek, SeekFrom};
2 use futures_core::future::Future;
3 use futures_core::task::{Context, Poll};
4 use std::io;
5 use std::pin::Pin;
6 
7 /// Future for the [`seek`](crate::io::AsyncSeekExt::seek) method.
8 #[derive(Debug)]
9 #[must_use = "futures do nothing unless you `.await` or poll them"]
10 pub struct Seek<'a, S: ?Sized> {
11     seek: &'a mut S,
12     pos: SeekFrom,
13 }
14 
15 impl<S: ?Sized + Unpin> Unpin for Seek<'_, S> {}
16 
17 impl<'a, S: AsyncSeek + ?Sized + Unpin> Seek<'a, S> {
new(seek: &'a mut S, pos: SeekFrom) -> Self18     pub(super) fn new(seek: &'a mut S, pos: SeekFrom) -> Self {
19         Self { seek, pos }
20     }
21 }
22 
23 impl<S: AsyncSeek + ?Sized + Unpin> Future for Seek<'_, S> {
24     type Output = io::Result<u64>;
25 
poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output>26     fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
27         let this = &mut *self;
28         Pin::new(&mut this.seek).poll_seek(cx, this.pos)
29     }
30 }
31