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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 19:33:14 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 19:33:14 +0000
commit36d22d82aa202bb199967e9512281e9a53db42c9 (patch)
tree105e8c98ddea1c1e4784a60a5a6410fa416be2de /third_party/rust/tokio/src/time/driver/sleep.rs
parentInitial commit. (diff)
downloadfirefox-esr-upstream.tar.xz
firefox-esr-upstream.zip
Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'third_party/rust/tokio/src/time/driver/sleep.rs')
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diff --git a/third_party/rust/tokio/src/time/driver/sleep.rs b/third_party/rust/tokio/src/time/driver/sleep.rs
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+#[cfg(all(tokio_unstable, feature = "tracing"))]
+use crate::time::driver::ClockTime;
+use crate::time::driver::{Handle, TimerEntry};
+use crate::time::{error::Error, Duration, Instant};
+use crate::util::trace;
+
+use pin_project_lite::pin_project;
+use std::future::Future;
+use std::panic::Location;
+use std::pin::Pin;
+use std::task::{self, Poll};
+
+/// 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
+// Alias for old name in 0.x
+#[cfg_attr(docsrs, doc(alias = "delay_until"))]
+#[track_caller]
+pub fn sleep_until(deadline: Instant) -> Sleep {
+ return Sleep::new_timeout(deadline, trace::caller_location());
+}
+
+/// 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.
+///
+/// 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
+// Alias for old name in 0.x
+#[cfg_attr(docsrs, doc(alias = "delay_for"))]
+#[cfg_attr(docsrs, doc(alias = "wait"))]
+#[track_caller]
+pub fn sleep(duration: Duration) -> Sleep {
+ let location = trace::caller_location();
+
+ match Instant::now().checked_add(duration) {
+ Some(deadline) => Sleep::new_timeout(deadline, location),
+ None => Sleep::new_timeout(Instant::far_future(), location),
+ }
+}
+
+pin_project! {
+ /// 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
+ // Alias for old name in 0.2
+ #[cfg_attr(docsrs, doc(alias = "Delay"))]
+ #[derive(Debug)]
+ #[must_use = "futures do nothing unless you `.await` or poll them"]
+ pub struct Sleep {
+ inner: Inner,
+
+ // The link between the `Sleep` instance and the timer that drives it.
+ #[pin]
+ entry: TimerEntry,
+ }
+}
+
+cfg_trace! {
+ #[derive(Debug)]
+ struct Inner {
+ deadline: Instant,
+ ctx: trace::AsyncOpTracingCtx,
+ time_source: ClockTime,
+ }
+}
+
+cfg_not_trace! {
+ #[derive(Debug)]
+ struct Inner {
+ deadline: Instant,
+ }
+}
+
+impl Sleep {
+ #[cfg_attr(not(all(tokio_unstable, feature = "tracing")), allow(unused_variables))]
+ pub(crate) fn new_timeout(
+ deadline: Instant,
+ location: Option<&'static Location<'static>>,
+ ) -> Sleep {
+ let handle = Handle::current();
+ let entry = TimerEntry::new(&handle, deadline);
+
+ #[cfg(all(tokio_unstable, feature = "tracing"))]
+ let inner = {
+ let time_source = handle.time_source().clone();
+ let deadline_tick = time_source.deadline_to_tick(deadline);
+ let duration = deadline_tick.checked_sub(time_source.now()).unwrap_or(0);
+
+ let location = location.expect("should have location if tracing");
+ let resource_span = tracing::trace_span!(
+ "runtime.resource",
+ concrete_type = "Sleep",
+ kind = "timer",
+ loc.file = location.file(),
+ loc.line = location.line(),
+ loc.col = location.column(),
+ );
+
+ let async_op_span = resource_span.in_scope(|| {
+ tracing::trace!(
+ target: "runtime::resource::state_update",
+ duration = duration,
+ duration.unit = "ms",
+ duration.op = "override",
+ );
+
+ tracing::trace_span!("runtime.resource.async_op", source = "Sleep::new_timeout")
+ });
+
+ let async_op_poll_span =
+ async_op_span.in_scope(|| tracing::trace_span!("runtime.resource.async_op.poll"));
+
+ let ctx = trace::AsyncOpTracingCtx {
+ async_op_span,
+ async_op_poll_span,
+ resource_span,
+ };
+
+ Inner {
+ deadline,
+ ctx,
+ time_source,
+ }
+ };
+
+ #[cfg(not(all(tokio_unstable, feature = "tracing")))]
+ let inner = Inner { deadline };
+
+ Sleep { inner, entry }
+ }
+
+ pub(crate) fn far_future(location: Option<&'static Location<'static>>) -> Sleep {
+ Self::new_timeout(Instant::far_future(), location)
+ }
+
+ /// Returns the instant at which the future will complete.
+ pub fn deadline(&self) -> Instant {
+ self.inner.deadline
+ }
+
+ /// Returns `true` if `Sleep` has elapsed.
+ ///
+ /// A `Sleep` instance is elapsed when the requested duration has elapsed.
+ pub fn is_elapsed(&self) -> bool {
+ self.entry.is_elapsed()
+ }
+
+ /// 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
+ pub fn reset(self: Pin<&mut Self>, deadline: Instant) {
+ self.reset_inner(deadline)
+ }
+
+ fn reset_inner(self: Pin<&mut Self>, deadline: Instant) {
+ let me = self.project();
+ me.entry.reset(deadline);
+ (*me.inner).deadline = deadline;
+
+ #[cfg(all(tokio_unstable, feature = "tracing"))]
+ {
+ let _resource_enter = me.inner.ctx.resource_span.enter();
+ me.inner.ctx.async_op_span =
+ tracing::trace_span!("runtime.resource.async_op", source = "Sleep::reset");
+ let _async_op_enter = me.inner.ctx.async_op_span.enter();
+
+ me.inner.ctx.async_op_poll_span =
+ tracing::trace_span!("runtime.resource.async_op.poll");
+
+ let duration = {
+ let now = me.inner.time_source.now();
+ let deadline_tick = me.inner.time_source.deadline_to_tick(deadline);
+ deadline_tick.checked_sub(now).unwrap_or(0)
+ };
+
+ tracing::trace!(
+ target: "runtime::resource::state_update",
+ duration = duration,
+ duration.unit = "ms",
+ duration.op = "override",
+ );
+ }
+ }
+
+ fn poll_elapsed(self: Pin<&mut Self>, cx: &mut task::Context<'_>) -> Poll<Result<(), Error>> {
+ let me = self.project();
+
+ // Keep track of task budget
+ #[cfg(all(tokio_unstable, feature = "tracing"))]
+ let coop = ready!(trace_poll_op!(
+ "poll_elapsed",
+ crate::coop::poll_proceed(cx),
+ ));
+
+ #[cfg(any(not(tokio_unstable), not(feature = "tracing")))]
+ let coop = ready!(crate::coop::poll_proceed(cx));
+
+ let result = me.entry.poll_elapsed(cx).map(move |r| {
+ coop.made_progress();
+ r
+ });
+
+ #[cfg(all(tokio_unstable, feature = "tracing"))]
+ return trace_poll_op!("poll_elapsed", result);
+
+ #[cfg(any(not(tokio_unstable), not(feature = "tracing")))]
+ return result;
+ }
+}
+
+impl Future for Sleep {
+ type Output = ();
+
+ // `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.
+ fn poll(mut self: Pin<&mut Self>, cx: &mut task::Context<'_>) -> Poll<Self::Output> {
+ #[cfg(all(tokio_unstable, feature = "tracing"))]
+ let _res_span = self.inner.ctx.resource_span.clone().entered();
+ #[cfg(all(tokio_unstable, feature = "tracing"))]
+ let _ao_span = self.inner.ctx.async_op_span.clone().entered();
+ #[cfg(all(tokio_unstable, feature = "tracing"))]
+ let _ao_poll_span = self.inner.ctx.async_op_poll_span.clone().entered();
+ match ready!(self.as_mut().poll_elapsed(cx)) {
+ Ok(()) => Poll::Ready(()),
+ Err(e) => panic!("timer error: {}", e),
+ }
+ }
+}