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