[−]Struct weechat::Task
async
only.A spawned task.
A Task
can be awaited to retrieve the output of its future.
Dropping a Task
cancels it, which means its future won't be polled again. To drop the
Task
handle without canceling it, use detach()
instead. To cancel a
task gracefully and wait until it is fully destroyed, use the cancel()
method.
Note that canceling a task actually wakes it and reschedules one last time. Then, the executor
can destroy the task by simply dropping its [Runnable
][super::Runnable
] or by invoking
[run()
][super::Runnable::run()
].
Examples
use smol::{future, Executor}; use std::thread; let ex = Executor::new(); // Spawn a future onto the executor. let task = ex.spawn(async { println!("Hello from a task!"); 1 + 2 }); // Run an executor thread. thread::spawn(move || future::block_on(ex.run(future::pending::<()>()))); // Wait for the task's output. assert_eq!(future::block_on(task), 3);
Implementations
impl<T> Task<T>
pub fn detach(self)
async
only.Detaches the task to let it keep running in the background.
Examples
use smol::{Executor, Timer}; use std::time::Duration; let ex = Executor::new(); // Spawn a deamon future. ex.spawn(async { loop { println!("I'm a daemon task looping forever."); Timer::after(Duration::from_secs(1)).await; } }) .detach();
pub async fn cancel(self) -> Option<T>
async
only.Cancels the task and waits for it to stop running.
Returns the task's output if it was completed just before it got canceled, or None
if
it didn't complete.
While it's possible to simply drop the Task
to cancel it, this is a cleaner way of
canceling because it also waits for the task to stop running.
Examples
use smol::{future, Executor, Timer}; use std::thread; use std::time::Duration; let ex = Executor::new(); // Spawn a deamon future. let task = ex.spawn(async { loop { println!("Even though I'm in an infinite loop, you can still cancel me!"); Timer::after(Duration::from_secs(1)).await; } }); // Run an executor thread. thread::spawn(move || future::block_on(ex.run(future::pending::<()>()))); future::block_on(async { Timer::after(Duration::from_secs(3)).await; task.cancel().await; });
Trait Implementations
impl<T> Debug for Task<T>
impl<T> Drop for Task<T>
fn drop(&mut self)
impl<T> Future for Task<T>
type Output = T
The type of value produced on completion.
fn poll(
self: Pin<&mut Task<T>>,
cx: &mut Context<'_>
) -> Poll<<Task<T> as Future>::Output>
self: Pin<&mut Task<T>>,
cx: &mut Context<'_>
) -> Poll<<Task<T> as Future>::Output>
impl<T> RefUnwindSafe for Task<T>
impl<T> Send for Task<T> where
T: Send,
T: Send,
impl<T> Sync for Task<T>
impl<T> Unpin for Task<T>
impl<T> UnwindSafe for Task<T>
Blanket Implementations
impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,
impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
fn borrow_mut(&mut self) -> &mut T
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impl<T> From<T> for T
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impl<T> FutureExt for T where
T: Future + ?Sized,
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T: Future + ?Sized,
fn map<U, F>(self, f: F) -> Map<Self, F> where
F: FnOnce(Self::Output) -> U,
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F: FnOnce(Self::Output) -> U,
fn map_into<U>(self) -> MapInto<Self, U> where
Self::Output: Into<U>,
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Self::Output: Into<U>,
fn then<Fut, F>(self, f: F) -> Then<Self, Fut, F> where
F: FnOnce(Self::Output) -> Fut,
Fut: Future,
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F: FnOnce(Self::Output) -> Fut,
Fut: Future,
fn left_future<B>(self) -> Either<Self, B> where
B: Future<Output = Self::Output>,
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B: Future<Output = Self::Output>,
fn right_future<A>(self) -> Either<A, Self> where
A: Future<Output = Self::Output>,
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A: Future<Output = Self::Output>,
fn into_stream(self) -> IntoStream<Self>
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fn flatten(self) -> Flatten<Self> where
Self::Output: Future,
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Self::Output: Future,
fn flatten_stream(self) -> FlattenStream<Self> where
Self::Output: Stream,
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Self::Output: Stream,
fn fuse(self) -> Fuse<Self>
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fn inspect<F>(self, f: F) -> Inspect<Self, F> where
F: FnOnce(&Self::Output),
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F: FnOnce(&Self::Output),
fn catch_unwind(self) -> CatchUnwind<Self> where
Self: UnwindSafe,
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Self: UnwindSafe,
fn shared(self) -> Shared<Self> where
Self::Output: Clone,
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Self::Output: Clone,
fn remote_handle(self) -> (Remote<Self>, RemoteHandle<Self::Output>)
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fn boxed<'a>(self) -> Pin<Box<dyn Future<Output = Self::Output> + 'a + Send>> where
Self: Send + 'a,
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Self: Send + 'a,
fn boxed_local<'a>(self) -> Pin<Box<dyn Future<Output = Self::Output> + 'a>> where
Self: 'a,
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Self: 'a,
fn unit_error(self) -> UnitError<Self>
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fn never_error(self) -> NeverError<Self>
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fn poll_unpin(&mut self, cx: &mut Context<'_>) -> Poll<Self::Output> where
Self: Unpin,
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Self: Unpin,
fn now_or_never(self) -> Option<Self::Output>
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impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<F> IntoFuture for F where
F: Future,
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F: Future,
type Output = <F as Future>::Output
into_future
)The output that the future will produce on completion.
type Future = F
into_future
)Which kind of future are we turning this into?
fn into_future(self) -> <F as IntoFuture>::Future
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impl<T, U> TryFrom<U> for T where
U: Into<T>,
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U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<F, T, E> TryFuture for F where
F: Future<Output = Result<T, E>> + ?Sized,
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F: Future<Output = Result<T, E>> + ?Sized,
type Ok = T
The type of successful values yielded by this future
type Error = E
The type of failures yielded by this future
fn try_poll(
self: Pin<&mut F>,
cx: &mut Context<'_>
) -> Poll<<F as Future>::Output>
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self: Pin<&mut F>,
cx: &mut Context<'_>
) -> Poll<<F as Future>::Output>
impl<Fut> TryFutureExt for Fut where
Fut: TryFuture + ?Sized,
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Fut: TryFuture + ?Sized,
fn flatten_sink<Item>(self) -> FlattenSink<Self, Self::Ok> where
Self::Ok: Sink<Item>,
<Self::Ok as Sink<Item>>::Error == Self::Error,
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Self::Ok: Sink<Item>,
<Self::Ok as Sink<Item>>::Error == Self::Error,
fn map_ok<T, F>(self, f: F) -> MapOk<Self, F> where
F: FnOnce(Self::Ok) -> T,
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F: FnOnce(Self::Ok) -> T,
fn map_ok_or_else<T, E, F>(self, e: E, f: F) -> MapOkOrElse<Self, F, E> where
E: FnOnce(Self::Error) -> T,
F: FnOnce(Self::Ok) -> T,
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E: FnOnce(Self::Error) -> T,
F: FnOnce(Self::Ok) -> T,
fn map_err<E, F>(self, f: F) -> MapErr<Self, F> where
F: FnOnce(Self::Error) -> E,
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F: FnOnce(Self::Error) -> E,
fn err_into<E>(self) -> ErrInto<Self, E> where
Self::Error: Into<E>,
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Self::Error: Into<E>,
fn ok_into<U>(self) -> OkInto<Self, U> where
Self::Ok: Into<U>,
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Self::Ok: Into<U>,
fn and_then<Fut, F>(self, f: F) -> AndThen<Self, Fut, F> where
F: FnOnce(Self::Ok) -> Fut,
Fut: TryFuture<Error = Self::Error>,
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F: FnOnce(Self::Ok) -> Fut,
Fut: TryFuture<Error = Self::Error>,
fn or_else<Fut, F>(self, f: F) -> OrElse<Self, Fut, F> where
F: FnOnce(Self::Error) -> Fut,
Fut: TryFuture<Ok = Self::Ok>,
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F: FnOnce(Self::Error) -> Fut,
Fut: TryFuture<Ok = Self::Ok>,
fn inspect_ok<F>(self, f: F) -> InspectOk<Self, F> where
F: FnOnce(&Self::Ok),
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F: FnOnce(&Self::Ok),
fn inspect_err<F>(self, f: F) -> InspectErr<Self, F> where
F: FnOnce(&Self::Error),
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F: FnOnce(&Self::Error),
fn try_flatten(self) -> TryFlatten<Self, Self::Ok> where
Self::Ok: TryFuture,
<Self::Ok as TryFuture>::Error == Self::Error,
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Self::Ok: TryFuture,
<Self::Ok as TryFuture>::Error == Self::Error,
fn try_flatten_stream(self) -> TryFlattenStream<Self> where
Self::Ok: TryStream,
<Self::Ok as TryStream>::Error == Self::Error,
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Self::Ok: TryStream,
<Self::Ok as TryStream>::Error == Self::Error,
fn unwrap_or_else<F>(self, f: F) -> UnwrapOrElse<Self, F> where
F: FnOnce(Self::Error) -> Self::Ok,
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F: FnOnce(Self::Error) -> Self::Ok,
fn into_future(self) -> IntoFuture<Self>
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fn try_poll_unpin(
&mut self,
cx: &mut Context<'_>
) -> Poll<Result<Self::Ok, Self::Error>> where
Self: Unpin,
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&mut self,
cx: &mut Context<'_>
) -> Poll<Result<Self::Ok, Self::Error>> where
Self: Unpin,
impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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U: TryFrom<T>,