Added `.pad_time()` extension method for `T: Future` (TODO: Currently only compiles on nightly as it requires `impl Future` in trait impl, and must be boxed on stable. But `Future.boxed()` extension requires the future to be `Send` for some reason, which we don"t require. Find a way to box the future without it needing to be `Send`.) Fortune for rsh's current commit: Curse − 凶pipelined-socket-buffering
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GPG Key ID:
284488987C31F630
@ -1,2 +1,75 @@
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//! Syncronisation helpers
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use super::*;
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use futures::{
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Future,
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};
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use tokio::time::Duration;
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/// Force a future to take *at least* a specific amount of time to complete.
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///
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/// If the future takes longer than `time` to complete, no additional delay is added.
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/// If `time` is zero, no delay is added.
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///
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/// # Panics
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/// The returned future will panic if
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/// * The future itself panics
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/// * We are unable to convert the future's duration from `chrono`'s duration span to std's duration span
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pub fn timesync<'a, T, F>(future: F, time: Duration) -> impl Future<Output = T> + 'a
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where F: Future<Output=T> + 'a
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{
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use chrono::prelude::*;
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#[cold]
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#[inline(never)]
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fn _panic_failed_tmconv(orig: chrono::Duration, error: impl Into<eyre::Report>)
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{
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panic!("Failed to convert chrono duration span {:?} to std duration span: {}", orig, error.into());
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}
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async move {
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let now = Utc::now();
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let r = future.await;
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if time.is_zero() {
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return r;
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}
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let after = Utc::now();
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let duration = after - now;
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match duration.to_std() {
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Ok(taken)
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if taken < time => {
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// Delay for the remaining time
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tokio::time::delay_for(time - taken).await;
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},
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Err(error) => _panic_failed_tmconv(duration, error),
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// At least `time` has passed
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_ => (),
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}
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r
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}
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}
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pub trait TimeSyncExt<'a>: Future + Sized + 'a
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{
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type OutputFuture: Future<Output = Self::Output> + 'a;
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fn pad_time(self, time: Duration) -> Self::OutputFuture;
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}
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#[cfg(nightly)]
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impl<'a, F> TimeSyncExt<'a> for F
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where F: Future + 'a
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{
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//#[cfg(nightly)]
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type OutputFuture = impl Future<Output = Self::Output> + 'a;
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//#[cfg(not(nightly))]
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//type OutputFuture = futures::future::BoxFuture<'a, Self::Output>; //TODO: Requires `Send` bound for some reason.
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fn pad_time(self, time: Duration) -> Self::OutputFuture {
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/*#[cfg(not(nightly))] {
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use futures::prelude::*;
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return timesync(self, time).boxed();
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}
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#[cfg(nightly)] {
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return*/ timesync(self, time)
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//}
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}
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}
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