_ Git - rust-lightning/blob - lightning/src/util/async_poll.rs

   1 // This file is Copyright its original authors, visible in version control
   2 // history.
   3 //
   4 // This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
   5 // or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
   7 // You may not use this file except in accordance with one or both of these
   8 // licenses.
   9
  10 //! Some utilities to make working with the standard library's [`Future`]s easier
  11
  12 use crate::prelude::*;
  13 use core::future::Future;
  14 use core::marker::Unpin;
  15 use core::pin::Pin;
  16 use core::task::{Context, Poll};
  17
  18 pub(crate) struct MultiFuturePoller<F: Future<Output = ()> + Unpin>(pub Vec<Option<F>>);
  19
  20 impl<F: Future<Output = ()> + Unpin> Future for MultiFuturePoller<F> {
  21         type Output = ();
  22         fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<()> {
  23                 let mut have_pending_futures = false;
  24                 for fut_option in self.get_mut().0.iter_mut() {
  25                         let mut fut = match fut_option.take() {
  26                                 None => continue,
  27                                 Some(fut) => fut,
  28                         };
  29                         match Pin::new(&mut fut).poll(cx) {
  30                                 Poll::Ready(()) => {},
  31                                 Poll::Pending => {
  32                                         have_pending_futures = true;
  33                                         *fut_option = Some(fut);
  34                                 },
  35                         }
  36                 }
  37                 if have_pending_futures {
  38                         Poll::Pending
  39                 } else {
  40                         Poll::Ready(())
  41                 }
  42         }
  43 }