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//! Provides a timer trait with timer-like functions
//!
//! Example using tokio timer:
//! ```rust
//! use std::{
//! future::Future,
//! pin::Pin,
//! task::{Context, Poll},
//! time::{Duration, Instant},
//! };
//!
//! use pin_project_lite::pin_project;
//! use hyper::rt::{Timer, Sleep};
//!
//! #[derive(Clone, Debug)]
//! pub struct TokioTimer;
//!
//! impl Timer for TokioTimer {
//! fn sleep(&self, duration: Duration) -> Pin<Box<dyn Sleep>> {
//! Box::pin(TokioSleep {
//! inner: tokio::time::sleep(duration),
//! })
//! }
//!
//! fn sleep_until(&self, deadline: Instant) -> Pin<Box<dyn Sleep>> {
//! Box::pin(TokioSleep {
//! inner: tokio::time::sleep_until(deadline.into()),
//! })
//! }
//!
//! fn reset(&self, sleep: &mut Pin<Box<dyn Sleep>>, new_deadline: Instant) {
//! if let Some(sleep) = sleep.as_mut().downcast_mut_pin::<TokioSleep>() {
//! sleep.reset(new_deadline.into())
//! }
//! }
//! }
//!
//! pin_project! {
//! pub(crate) struct TokioSleep {
//! #[pin]
//! pub(crate) inner: tokio::time::Sleep,
//! }
//! }
//!
//! impl Future for TokioSleep {
//! type Output = ();
//!
//! fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
//! self.project().inner.poll(cx)
//! }
//! }
//!
//! impl Sleep for TokioSleep {}
//!
//! impl TokioSleep {
//! pub fn reset(self: Pin<&mut Self>, deadline: Instant) {
//! self.project().inner.as_mut().reset(deadline.into());
//! }
//! }
//! ```
use std::{
any::TypeId,
future::Future,
pin::Pin,
time::{Duration, Instant},
};
/// A timer which provides timer-like functions.
pub trait Timer {
/// Return a future that resolves in `duration` time.
fn sleep(&self, duration: Duration) -> Pin<Box<dyn Sleep>>;
/// Return a future that resolves at `deadline`.
fn sleep_until(&self, deadline: Instant) -> Pin<Box<dyn Sleep>>;
/// Reset a future to resolve at `new_deadline` instead.
fn reset(&self, sleep: &mut Pin<Box<dyn Sleep>>, new_deadline: Instant) {
*sleep = self.sleep_until(new_deadline);
}
}
/// A future returned by a `Timer`.
pub trait Sleep: Send + Sync + Future<Output = ()> {
#[doc(hidden)]
/// This method is private and can not be implemented by downstream crate
fn __type_id(&self, _: private::Sealed) -> TypeId
where
Self: 'static,
{
TypeId::of::<Self>()
}
}
impl dyn Sleep {
//! This is a re-implementation of downcast methods from std::any::Any
/// Check whether the type is the same as `T`
pub fn is<T>(&self) -> bool
where
T: Sleep + 'static,
{
self.__type_id(private::Sealed {}) == TypeId::of::<T>()
}
/// Downcast a pinned &mut Sleep object to its original type
pub fn downcast_mut_pin<T>(self: Pin<&mut Self>) -> Option<Pin<&mut T>>
where
T: Sleep + 'static,
{
if self.is::<T>() {
unsafe {
let inner = Pin::into_inner_unchecked(self);
Some(Pin::new_unchecked(
&mut *(&mut *inner as *mut dyn Sleep as *mut T),
))
}
} else {
None
}
}
}
mod private {
#![allow(missing_debug_implementations)]
pub struct Sealed {}
}