Struct wasm_timer::Timer

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pub struct Timer { /* private fields */ }
Expand description

A “timer heap” used to power separately owned instances of Delay and Interval.

This timer is implemented as a priority queued-based heap. Each Timer contains a few primary methods which which to drive it:

  • next_wake indicates how long the ambient system needs to sleep until it invokes further processing on a Timer
  • advance_to is what actually fires timers on the Timer, and should be called essentially every iteration of the event loop, or when the time specified by next_wake has elapsed.
  • The Future implementation for Timer is used to process incoming timer updates and requests. This is used to schedule new timeouts, update existing ones, or delete existing timeouts. The Future implementation will never resolve, but it’ll schedule notifications of when to wake up and process more messages.

Note that if you’re using this crate you probably don’t need to use a Timer as there is a global one already available for you run on a helper thread. If this isn’t desirable, though, then the TimerHandle::set_fallback method can be used instead!

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impl Timer

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pub fn new() -> Timer

Creates a new timer heap ready to create new timers.

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pub fn handle(&self) -> TimerHandle

Returns a handle to this timer heap, used to create new timeouts.

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pub fn next_event(&self) -> Option<Instant>

Returns the time at which this timer next needs to be invoked with advance_to.

Event loops or threads typically want to sleep until the specified instant.

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pub fn advance(&mut self)

Proces any timers which are supposed to fire at or before the current instant.

This method is equivalent to self.advance_to(Instant::now()).

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pub fn advance_to(&mut self, now: Instant)

Proces any timers which are supposed to fire before now specified.

This method should be called on Timer periodically to advance the internal state and process any pending timers which need to fire.

Trait Implementations§

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impl Debug for Timer

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fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter. Read more
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impl Drop for Timer

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fn drop(&mut self)

Executes the destructor for this type. Read more
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impl Future for Timer

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type Output = ()

The type of value produced on completion.
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fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output>

Attempt to resolve the future to a final value, registering the current task for wakeup if the value is not yet available. Read more

Auto Trait Implementations§

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impl Freeze for Timer

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impl !RefUnwindSafe for Timer

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impl Send for Timer

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impl Sync for Timer

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impl Unpin for Timer

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impl !UnwindSafe for Timer

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T> FutureExt for T
where T: Future + ?Sized,

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fn map<U, F>(self, f: F) -> Map<Self, F>
where F: FnOnce(Self::Output) -> U, Self: Sized,

Map this future’s output to a different type, returning a new future of the resulting type. Read more
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fn map_into<U>(self) -> MapInto<Self, U>
where Self::Output: Into<U>, Self: Sized,

Map this future’s output to a different type, returning a new future of the resulting type. Read more
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fn then<Fut, F>(self, f: F) -> Then<Self, Fut, F>
where F: FnOnce(Self::Output) -> Fut, Fut: Future, Self: Sized,

Chain on a computation for when a future finished, passing the result of the future to the provided closure f. Read more
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fn left_future<B>(self) -> Either<Self, B>
where B: Future<Output = Self::Output>, Self: Sized,

Wrap this future in an Either future, making it the left-hand variant of that Either. Read more
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fn right_future<A>(self) -> Either<A, Self>
where A: Future<Output = Self::Output>, Self: Sized,

Wrap this future in an Either future, making it the right-hand variant of that Either. Read more
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fn into_stream(self) -> IntoStream<Self>
where Self: Sized,

Convert this future into a single element stream. Read more
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fn flatten(self) -> Flatten<Self>
where Self::Output: Future, Self: Sized,

Flatten the execution of this future when the output of this future is itself another future. Read more
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fn flatten_stream(self) -> FlattenStream<Self>
where Self::Output: Stream, Self: Sized,

Flatten the execution of this future when the successful result of this future is a stream. Read more
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fn fuse(self) -> Fuse<Self>
where Self: Sized,

Fuse a future such that poll will never again be called once it has completed. This method can be used to turn any Future into a FusedFuture. Read more
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fn inspect<F>(self, f: F) -> Inspect<Self, F>
where F: FnOnce(&Self::Output), Self: Sized,

Do something with the output of a future before passing it on. Read more
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fn catch_unwind(self) -> CatchUnwind<Self>
where Self: Sized + UnwindSafe,

Catches unwinding panics while polling the future. Read more
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fn shared(self) -> Shared<Self>
where Self: Sized, Self::Output: Clone,

Create a cloneable handle to this future where all handles will resolve to the same result. Read more
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fn remote_handle(self) -> (Remote<Self>, RemoteHandle<Self::Output>)
where Self: Sized,

Turn this future into a future that yields () on completion and sends its output to another future on a separate task. Read more
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fn boxed<'a>(self) -> Pin<Box<dyn Future<Output = Self::Output> + Send + 'a>>
where Self: Sized + Send + 'a,

Wrap the future in a Box, pinning it. Read more
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fn boxed_local<'a>(self) -> Pin<Box<dyn Future<Output = Self::Output> + 'a>>
where Self: Sized + 'a,

Wrap the future in a Box, pinning it. Read more
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fn unit_error(self) -> UnitError<Self>
where Self: Sized,

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fn never_error(self) -> NeverError<Self>
where Self: Sized,

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fn poll_unpin(&mut self, cx: &mut Context<'_>) -> Poll<Self::Output>
where Self: Unpin,

A convenience for calling Future::poll on Unpin future types.
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fn now_or_never(self) -> Option<Self::Output>
where Self: Sized,

Evaluates and consumes the future, returning the resulting output if the future is ready after the first call to Future::poll. Read more
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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<F> IntoFuture for F
where F: Future,

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type Output = <F as Future>::Output

The output that the future will produce on completion.
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type IntoFuture = F

Which kind of future are we turning this into?
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fn into_future(self) -> <F as IntoFuture>::IntoFuture

Creates a future from a value. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.