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use tokio_timer::Deadline; use futures::Future; use std::time::Instant; /// An extension trait for `Future` that provides a variety of convenient /// combinator functions. /// /// Currently, there only is a [`deadline`] function, but this will increase /// over time. /// /// Users are not expected to implement this trait. All types that implement /// `Future` already implement `FutureExt`. /// /// This trait can be imported directly or via the Tokio prelude: `use /// tokio::prelude::*`. /// /// [`deadline`]: #method.deadline pub trait FutureExt: Future { /// Creates a new future which allows `self` until `deadline`. /// /// This combinator creates a new future which wraps the receiving future /// with a deadline. The returned future is allowed to execute until it /// completes or `deadline` is reached, whichever happens first. /// /// If the future completes before `deadline` then the future will resolve /// with that item. Otherwise the future will resolve to an error once /// `deadline` is reached. /// /// # Examples /// /// ``` /// # extern crate tokio; /// # extern crate futures; /// use tokio::prelude::*; /// use std::time::{Duration, Instant}; /// # use futures::future::{self, FutureResult}; /// /// # fn long_future() -> FutureResult<(), ()> { /// # future::ok(()) /// # } /// # /// # fn main() { /// let future = long_future() /// .deadline(Instant::now() + Duration::from_secs(1)) /// .map_err(|e| println!("error = {:?}", e)); /// /// tokio::run(future); /// # } /// ``` fn deadline(self, deadline: Instant) -> Deadline<Self> where Self: Sized, { Deadline::new(self, deadline) } } impl<T: ?Sized> FutureExt for T where T: Future {}