| <!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="Source of the Rust file `/root/.cargo/git/checkouts/tokio-377c595163f99a10/dfe252d/tokio/src/time/sleep.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>sleep.rs - source</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceSerif4-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../FiraSans-Regular.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../FiraSans-Medium.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceCodePro-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceSerif4-Bold.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceCodePro-Semibold.ttf.woff2"><link rel="stylesheet" href="../../../normalize.css"><link rel="stylesheet" href="../../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" href="../../../ayu.css" disabled><link rel="stylesheet" href="../../../dark.css" disabled><link rel="stylesheet" href="../../../light.css" id="themeStyle"><script id="default-settings" ></script><script src="../../../storage.js"></script><script defer src="../../../source-script.js"></script><script defer src="../../../source-files.js"></script><script defer src="../../../main.js"></script><noscript><link rel="stylesheet" href="../../../noscript.css"></noscript><link rel="alternate icon" type="image/png" href="../../../favicon-16x16.png"><link rel="alternate icon" type="image/png" href="../../../favicon-32x32.png"><link rel="icon" type="image/svg+xml" href="../../../favicon.svg"></head><body class="rustdoc source"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><a class="sidebar-logo" href="../../../tokio/index.html"><div class="logo-container"><img class="rust-logo" src="../../../rust-logo.svg" alt="logo"></div></a></nav><main><div class="width-limiter"><nav class="sub"><a class="sub-logo-container" href="../../../tokio/index.html"><img class="rust-logo" src="../../../rust-logo.svg" alt="logo"></a><form class="search-form"><div class="search-container"><span></span><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><div id="help-button" title="help" tabindex="-1"><a href="../../../help.html">?</a></div><div id="settings-menu" tabindex="-1"><a href="../../../settings.html" title="settings"><img width="22" height="22" alt="Change settings" src="../../../wheel.svg"></a></div></div></form></nav><section id="main-content" class="content"><div class="example-wrap"><pre class="src-line-numbers"><span id="1">1</span> |
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| </pre><pre class="rust"><code><span class="kw">use </span><span class="kw">crate</span>::runtime::time::TimerEntry; |
| <span class="kw">use </span><span class="kw">crate</span>::time::{error::Error, Duration, Instant}; |
| <span class="kw">use </span><span class="kw">crate</span>::util::trace; |
| |
| <span class="kw">use </span>pin_project_lite::pin_project; |
| <span class="kw">use </span>std::future::Future; |
| <span class="kw">use </span>std::panic::Location; |
| <span class="kw">use </span>std::pin::Pin; |
| <span class="kw">use </span>std::task::{<span class="self">self</span>, Poll}; |
| |
| <span class="doccomment">/// Waits until `deadline` is reached. |
| /// |
| /// No work is performed while awaiting on the sleep future to complete. `Sleep` |
| /// operates at millisecond granularity and should not be used for tasks that |
| /// require high-resolution timers. |
| /// |
| /// To run something regularly on a schedule, see [`interval`]. |
| /// |
| /// # Cancellation |
| /// |
| /// Canceling a sleep instance is done by dropping the returned future. No additional |
| /// cleanup work is required. |
| /// |
| /// # Examples |
| /// |
| /// Wait 100ms and print "100 ms have elapsed". |
| /// |
| /// ``` |
| /// use tokio::time::{sleep_until, Instant, Duration}; |
| /// |
| /// #[tokio::main] |
| /// async fn main() { |
| /// sleep_until(Instant::now() + Duration::from_millis(100)).await; |
| /// println!("100 ms have elapsed"); |
| /// } |
| /// ``` |
| /// |
| /// See the documentation for the [`Sleep`] type for more examples. |
| /// |
| /// # Panics |
| /// |
| /// This function panics if there is no current timer set. |
| /// |
| /// It can be triggered when [`Builder::enable_time`] or |
| /// [`Builder::enable_all`] are not included in the builder. |
| /// |
| /// It can also panic whenever a timer is created outside of a |
| /// Tokio runtime. That is why `rt.block_on(sleep(...))` will panic, |
| /// since the function is executed outside of the runtime. |
| /// Whereas `rt.block_on(async {sleep(...).await})` doesn't panic. |
| /// And this is because wrapping the function on an async makes it lazy, |
| /// and so gets executed inside the runtime successfully without |
| /// panicking. |
| /// |
| /// [`Sleep`]: struct@crate::time::Sleep |
| /// [`interval`]: crate::time::interval() |
| /// [`Builder::enable_time`]: crate::runtime::Builder::enable_time |
| /// [`Builder::enable_all`]: crate::runtime::Builder::enable_all |
| </span><span class="comment">// Alias for old name in 0.x |
| </span><span class="attribute">#[cfg_attr(docsrs, doc(alias = <span class="string">"delay_until"</span>))] |
| #[track_caller] |
| </span><span class="kw">pub fn </span>sleep_until(deadline: Instant) -> Sleep { |
| <span class="kw">return </span>Sleep::new_timeout(deadline, trace::caller_location()); |
| } |
| |
| <span class="doccomment">/// Waits until `duration` has elapsed. |
| /// |
| /// Equivalent to `sleep_until(Instant::now() + duration)`. An asynchronous |
| /// analog to `std::thread::sleep`. |
| /// |
| /// No work is performed while awaiting on the sleep future to complete. `Sleep` |
| /// operates at millisecond granularity and should not be used for tasks that |
| /// require high-resolution timers. The implementation is platform specific, |
| /// and some platforms (specifically Windows) will provide timers with a |
| /// larger resolution than 1 ms. |
| /// |
| /// To run something regularly on a schedule, see [`interval`]. |
| /// |
| /// The maximum duration for a sleep is 68719476734 milliseconds (approximately 2.2 years). |
| /// |
| /// # Cancellation |
| /// |
| /// Canceling a sleep instance is done by dropping the returned future. No additional |
| /// cleanup work is required. |
| /// |
| /// # Examples |
| /// |
| /// Wait 100ms and print "100 ms have elapsed". |
| /// |
| /// ``` |
| /// use tokio::time::{sleep, Duration}; |
| /// |
| /// #[tokio::main] |
| /// async fn main() { |
| /// sleep(Duration::from_millis(100)).await; |
| /// println!("100 ms have elapsed"); |
| /// } |
| /// ``` |
| /// |
| /// See the documentation for the [`Sleep`] type for more examples. |
| /// |
| /// # Panics |
| /// |
| /// This function panics if there is no current timer set. |
| /// |
| /// It can be triggered when [`Builder::enable_time`] or |
| /// [`Builder::enable_all`] are not included in the builder. |
| /// |
| /// It can also panic whenever a timer is created outside of a |
| /// Tokio runtime. That is why `rt.block_on(sleep(...))` will panic, |
| /// since the function is executed outside of the runtime. |
| /// Whereas `rt.block_on(async {sleep(...).await})` doesn't panic. |
| /// And this is because wrapping the function on an async makes it lazy, |
| /// and so gets executed inside the runtime successfully without |
| /// panicking. |
| /// |
| /// [`Sleep`]: struct@crate::time::Sleep |
| /// [`interval`]: crate::time::interval() |
| /// [`Builder::enable_time`]: crate::runtime::Builder::enable_time |
| /// [`Builder::enable_all`]: crate::runtime::Builder::enable_all |
| </span><span class="comment">// Alias for old name in 0.x |
| </span><span class="attribute">#[cfg_attr(docsrs, doc(alias = <span class="string">"delay_for"</span>))] |
| #[cfg_attr(docsrs, doc(alias = <span class="string">"wait"</span>))] |
| #[track_caller] |
| </span><span class="kw">pub fn </span>sleep(duration: Duration) -> Sleep { |
| <span class="kw">let </span>location = trace::caller_location(); |
| |
| <span class="kw">match </span>Instant::now().checked_add(duration) { |
| <span class="prelude-val">Some</span>(deadline) => Sleep::new_timeout(deadline, location), |
| <span class="prelude-val">None </span>=> Sleep::new_timeout(Instant::far_future(), location), |
| } |
| } |
| |
| <span class="macro">pin_project! </span>{ |
| <span class="doccomment">/// Future returned by [`sleep`](sleep) and [`sleep_until`](sleep_until). |
| /// |
| /// This type does not implement the `Unpin` trait, which means that if you |
| /// use it with [`select!`] or by calling `poll`, you have to pin it first. |
| /// If you use it with `.await`, this does not apply. |
| /// |
| /// # Examples |
| /// |
| /// Wait 100ms and print "100 ms have elapsed". |
| /// |
| /// ``` |
| /// use tokio::time::{sleep, Duration}; |
| /// |
| /// #[tokio::main] |
| /// async fn main() { |
| /// sleep(Duration::from_millis(100)).await; |
| /// println!("100 ms have elapsed"); |
| /// } |
| /// ``` |
| /// |
| /// Use with [`select!`]. Pinning the `Sleep` with [`tokio::pin!`] is |
| /// necessary when the same `Sleep` is selected on multiple times. |
| /// ```no_run |
| /// use tokio::time::{self, Duration, Instant}; |
| /// |
| /// #[tokio::main] |
| /// async fn main() { |
| /// let sleep = time::sleep(Duration::from_millis(10)); |
| /// tokio::pin!(sleep); |
| /// |
| /// loop { |
| /// tokio::select! { |
| /// () = &mut sleep => { |
| /// println!("timer elapsed"); |
| /// sleep.as_mut().reset(Instant::now() + Duration::from_millis(50)); |
| /// }, |
| /// } |
| /// } |
| /// } |
| /// ``` |
| /// Use in a struct with boxing. By pinning the `Sleep` with a `Box`, the |
| /// `HasSleep` struct implements `Unpin`, even though `Sleep` does not. |
| /// ``` |
| /// use std::future::Future; |
| /// use std::pin::Pin; |
| /// use std::task::{Context, Poll}; |
| /// use tokio::time::Sleep; |
| /// |
| /// struct HasSleep { |
| /// sleep: Pin<Box<Sleep>>, |
| /// } |
| /// |
| /// impl Future for HasSleep { |
| /// type Output = (); |
| /// |
| /// fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<()> { |
| /// self.sleep.as_mut().poll(cx) |
| /// } |
| /// } |
| /// ``` |
| /// Use in a struct with pin projection. This method avoids the `Box`, but |
| /// the `HasSleep` struct will not be `Unpin` as a consequence. |
| /// ``` |
| /// use std::future::Future; |
| /// use std::pin::Pin; |
| /// use std::task::{Context, Poll}; |
| /// use tokio::time::Sleep; |
| /// use pin_project_lite::pin_project; |
| /// |
| /// pin_project! { |
| /// struct HasSleep { |
| /// #[pin] |
| /// sleep: Sleep, |
| /// } |
| /// } |
| /// |
| /// impl Future for HasSleep { |
| /// type Output = (); |
| /// |
| /// fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<()> { |
| /// self.project().sleep.poll(cx) |
| /// } |
| /// } |
| /// ``` |
| /// |
| /// [`select!`]: ../macro.select.html |
| /// [`tokio::pin!`]: ../macro.pin.html |
| </span><span class="comment">// Alias for old name in 0.2 |
| </span><span class="attribute">#[cfg_attr(docsrs, doc(alias = <span class="string">"Delay"</span>))] |
| #[derive(Debug)] |
| #[must_use = <span class="string">"futures do nothing unless you `.await` or poll them"</span>] |
| </span><span class="kw">pub struct </span>Sleep { |
| inner: Inner, |
| |
| <span class="comment">// The link between the `Sleep` instance and the timer that drives it. |
| </span><span class="attribute">#[pin] |
| </span>entry: TimerEntry, |
| } |
| } |
| |
| <span class="macro">cfg_trace! </span>{ |
| <span class="attribute">#[derive(Debug)] |
| </span><span class="kw">struct </span>Inner { |
| deadline: Instant, |
| ctx: trace::AsyncOpTracingCtx, |
| } |
| } |
| |
| <span class="macro">cfg_not_trace! </span>{ |
| <span class="attribute">#[derive(Debug)] |
| </span><span class="kw">struct </span>Inner { |
| deadline: Instant, |
| } |
| } |
| |
| <span class="kw">impl </span>Sleep { |
| <span class="attribute">#[cfg_attr(not(all(tokio_unstable, feature = <span class="string">"tracing"</span>)), allow(unused_variables))] |
| #[track_caller] |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>new_timeout( |
| deadline: Instant, |
| location: <span class="prelude-ty">Option</span><<span class="kw-2">&</span><span class="lifetime">'static </span>Location<<span class="lifetime">'static</span>>>, |
| ) -> Sleep { |
| <span class="kw">use </span><span class="kw">crate</span>::runtime::scheduler; |
| |
| <span class="kw">let </span>handle = scheduler::Handle::current(); |
| <span class="kw">let </span>entry = TimerEntry::new(<span class="kw-2">&</span>handle, deadline); |
| |
| <span class="attribute">#[cfg(all(tokio_unstable, feature = <span class="string">"tracing"</span>))] |
| </span><span class="kw">let </span>inner = { |
| <span class="kw">let </span>handle = <span class="kw-2">&</span>handle.driver().time(); |
| <span class="kw">let </span>time_source = handle.time_source(); |
| <span class="kw">let </span>deadline_tick = time_source.deadline_to_tick(deadline); |
| <span class="kw">let </span>duration = deadline_tick.saturating_sub(time_source.now()); |
| |
| <span class="kw">let </span>location = location.expect(<span class="string">"should have location if tracing"</span>); |
| <span class="kw">let </span>resource_span = <span class="macro">tracing::trace_span!</span>( |
| <span class="string">"runtime.resource"</span>, |
| concrete_type = <span class="string">"Sleep"</span>, |
| kind = <span class="string">"timer"</span>, |
| loc.file = location.file(), |
| loc.line = location.line(), |
| loc.col = location.column(), |
| ); |
| |
| <span class="kw">let </span>async_op_span = resource_span.in_scope(|| { |
| <span class="macro">tracing::trace!</span>( |
| target: <span class="string">"runtime::resource::state_update"</span>, |
| duration = duration, |
| duration.unit = <span class="string">"ms"</span>, |
| duration.op = <span class="string">"override"</span>, |
| ); |
| |
| <span class="macro">tracing::trace_span!</span>(<span class="string">"runtime.resource.async_op"</span>, source = <span class="string">"Sleep::new_timeout"</span>) |
| }); |
| |
| <span class="kw">let </span>async_op_poll_span = |
| async_op_span.in_scope(|| <span class="macro">tracing::trace_span!</span>(<span class="string">"runtime.resource.async_op.poll"</span>)); |
| |
| <span class="kw">let </span>ctx = trace::AsyncOpTracingCtx { |
| async_op_span, |
| async_op_poll_span, |
| resource_span, |
| }; |
| |
| Inner { deadline, ctx } |
| }; |
| |
| <span class="attribute">#[cfg(not(all(tokio_unstable, feature = <span class="string">"tracing"</span>)))] |
| </span><span class="kw">let </span>inner = Inner { deadline }; |
| |
| Sleep { inner, entry } |
| } |
| |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>far_future(location: <span class="prelude-ty">Option</span><<span class="kw-2">&</span><span class="lifetime">'static </span>Location<<span class="lifetime">'static</span>>>) -> Sleep { |
| <span class="self">Self</span>::new_timeout(Instant::far_future(), location) |
| } |
| |
| <span class="doccomment">/// Returns the instant at which the future will complete. |
| </span><span class="kw">pub fn </span>deadline(<span class="kw-2">&</span><span class="self">self</span>) -> Instant { |
| <span class="self">self</span>.inner.deadline |
| } |
| |
| <span class="doccomment">/// Returns `true` if `Sleep` has elapsed. |
| /// |
| /// A `Sleep` instance is elapsed when the requested duration has elapsed. |
| </span><span class="kw">pub fn </span>is_elapsed(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| <span class="self">self</span>.entry.is_elapsed() |
| } |
| |
| <span class="doccomment">/// Resets the `Sleep` instance to a new deadline. |
| /// |
| /// Calling this function allows changing the instant at which the `Sleep` |
| /// future completes without having to create new associated state. |
| /// |
| /// This function can be called both before and after the future has |
| /// completed. |
| /// |
| /// To call this method, you will usually combine the call with |
| /// [`Pin::as_mut`], which lets you call the method without consuming the |
| /// `Sleep` itself. |
| /// |
| /// # Example |
| /// |
| /// ``` |
| /// use tokio::time::{Duration, Instant}; |
| /// |
| /// # #[tokio::main(flavor = "current_thread")] |
| /// # async fn main() { |
| /// let sleep = tokio::time::sleep(Duration::from_millis(10)); |
| /// tokio::pin!(sleep); |
| /// |
| /// sleep.as_mut().reset(Instant::now() + Duration::from_millis(20)); |
| /// # } |
| /// ``` |
| /// |
| /// See also the top-level examples. |
| /// |
| /// [`Pin::as_mut`]: fn@std::pin::Pin::as_mut |
| </span><span class="kw">pub fn </span>reset(<span class="self">self</span>: Pin<<span class="kw-2">&mut </span><span class="self">Self</span>>, deadline: Instant) { |
| <span class="self">self</span>.reset_inner(deadline) |
| } |
| |
| <span class="kw">fn </span>reset_inner(<span class="self">self</span>: Pin<<span class="kw-2">&mut </span><span class="self">Self</span>>, deadline: Instant) { |
| <span class="kw">let </span><span class="kw-2">mut </span>me = <span class="self">self</span>.project(); |
| me.entry.as_mut().reset(deadline); |
| (me.inner).deadline = deadline; |
| |
| <span class="attribute">#[cfg(all(tokio_unstable, feature = <span class="string">"tracing"</span>))] |
| </span>{ |
| <span class="kw">let </span>_resource_enter = me.inner.ctx.resource_span.enter(); |
| me.inner.ctx.async_op_span = |
| <span class="macro">tracing::trace_span!</span>(<span class="string">"runtime.resource.async_op"</span>, source = <span class="string">"Sleep::reset"</span>); |
| <span class="kw">let </span>_async_op_enter = me.inner.ctx.async_op_span.enter(); |
| |
| me.inner.ctx.async_op_poll_span = |
| <span class="macro">tracing::trace_span!</span>(<span class="string">"runtime.resource.async_op.poll"</span>); |
| |
| <span class="kw">let </span>duration = { |
| <span class="kw">let </span>time_source = me.entry.driver().time_source(); |
| <span class="kw">let </span>now = time_source.now(); |
| <span class="kw">let </span>deadline_tick = time_source.deadline_to_tick(deadline); |
| deadline_tick.saturating_sub(now) |
| }; |
| |
| <span class="macro">tracing::trace!</span>( |
| target: <span class="string">"runtime::resource::state_update"</span>, |
| duration = duration, |
| duration.unit = <span class="string">"ms"</span>, |
| duration.op = <span class="string">"override"</span>, |
| ); |
| } |
| } |
| |
| <span class="kw">fn </span>poll_elapsed(<span class="self">self</span>: Pin<<span class="kw-2">&mut </span><span class="self">Self</span>>, cx: <span class="kw-2">&mut </span>task::Context<<span class="lifetime">'_</span>>) -> Poll<<span class="prelude-ty">Result</span><(), Error>> { |
| <span class="kw">let </span>me = <span class="self">self</span>.project(); |
| |
| <span class="comment">// Keep track of task budget |
| </span><span class="attribute">#[cfg(all(tokio_unstable, feature = <span class="string">"tracing"</span>))] |
| </span><span class="kw">let </span>coop = <span class="macro">ready!</span>(<span class="macro">trace_poll_op!</span>( |
| <span class="string">"poll_elapsed"</span>, |
| <span class="kw">crate</span>::runtime::coop::poll_proceed(cx), |
| )); |
| |
| <span class="attribute">#[cfg(any(not(tokio_unstable), not(feature = <span class="string">"tracing"</span>)))] |
| </span><span class="kw">let </span>coop = <span class="macro">ready!</span>(<span class="kw">crate</span>::runtime::coop::poll_proceed(cx)); |
| |
| <span class="kw">let </span>result = me.entry.poll_elapsed(cx).map(<span class="kw">move </span>|r| { |
| coop.made_progress(); |
| r |
| }); |
| |
| <span class="attribute">#[cfg(all(tokio_unstable, feature = <span class="string">"tracing"</span>))] |
| </span><span class="kw">return </span><span class="macro">trace_poll_op!</span>(<span class="string">"poll_elapsed"</span>, result); |
| |
| <span class="attribute">#[cfg(any(not(tokio_unstable), not(feature = <span class="string">"tracing"</span>)))] |
| </span><span class="kw">return </span>result; |
| } |
| } |
| |
| <span class="kw">impl </span>Future <span class="kw">for </span>Sleep { |
| <span class="kw">type </span>Output = (); |
| |
| <span class="comment">// `poll_elapsed` can return an error in two cases: |
| // |
| // - AtCapacity: this is a pathological case where far too many |
| // sleep instances have been scheduled. |
| // - Shutdown: No timer has been setup, which is a mis-use error. |
| // |
| // Both cases are extremely rare, and pretty accurately fit into |
| // "logic errors", so we just panic in this case. A user couldn't |
| // really do much better if we passed the error onwards. |
| </span><span class="kw">fn </span>poll(<span class="kw-2">mut </span><span class="self">self</span>: Pin<<span class="kw-2">&mut </span><span class="self">Self</span>>, cx: <span class="kw-2">&mut </span>task::Context<<span class="lifetime">'_</span>>) -> Poll<<span class="self">Self</span>::Output> { |
| <span class="attribute">#[cfg(all(tokio_unstable, feature = <span class="string">"tracing"</span>))] |
| </span><span class="kw">let </span>_res_span = <span class="self">self</span>.inner.ctx.resource_span.clone().entered(); |
| <span class="attribute">#[cfg(all(tokio_unstable, feature = <span class="string">"tracing"</span>))] |
| </span><span class="kw">let </span>_ao_span = <span class="self">self</span>.inner.ctx.async_op_span.clone().entered(); |
| <span class="attribute">#[cfg(all(tokio_unstable, feature = <span class="string">"tracing"</span>))] |
| </span><span class="kw">let </span>_ao_poll_span = <span class="self">self</span>.inner.ctx.async_op_poll_span.clone().entered(); |
| <span class="kw">match </span><span class="macro">ready!</span>(<span class="self">self</span>.as_mut().poll_elapsed(cx)) { |
| <span class="prelude-val">Ok</span>(()) => Poll::Ready(()), |
| <span class="prelude-val">Err</span>(e) => <span class="macro">panic!</span>(<span class="string">"timer error: {}"</span>, e), |
| } |
| } |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../../" data-current-crate="tokio" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |