Struct slings::Task [−][src]
pub struct Task<T> { /* fields omitted */ }
Expand description
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
or by invoking
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
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();
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
Blanket Implementations
Mutably borrows from an owned value. Read more
Map this future’s output to a different type, returning a new future of the resulting type. Read more
Map this future’s output to a different type, returning a new future of the resulting type. Read more
Chain on a computation for when a future finished, passing the result of
the future to the provided closure f
. Read more
Wrap this future in an Either
future, making it the left-hand variant
of that Either
. Read more
Wrap this future in an Either
future, making it the right-hand variant
of that Either
. Read more
Convert this future into a single element stream. Read more
Flatten the execution of this future when the output of this future is itself another future. Read more
Flatten the execution of this future when the successful result of this future is a stream. Read more
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
Do something with the output of a future before passing it on. Read more
Catches unwinding panics while polling the future. Read more
Create a cloneable handle to this future where all handles will resolve to the same result. Read more
Wrap the future in a Box, pinning it. Read more
Wrap the future in a Box, pinning it. Read more
Turns a Future<Output = T>
into a
TryFuture<Ok = T, Error = ()
>. Read more
Turns a Future<Output = T>
into a
TryFuture<Ok = T, Error = Never
>. Read more
A convenience for calling Future::poll
on Unpin
future types.
Evaluates and consumes the future, returning the resulting output if
the future is ready after the first call to Future::poll
. Read more
into_future
)The output that the future will produce on completion.
type Future = F
type Future = F
into_future
)Which kind of future are we turning this into?
into_future
)Creates a future from a value.
Maps this future’s success value to a different value. Read more
fn map_ok_or_else<T, E, F>(self, e: E, f: F) -> MapOkOrElse<Self, F, E> where
F: FnOnce(Self::Ok) -> T,
E: FnOnce(Self::Error) -> T,
fn map_ok_or_else<T, E, F>(self, e: E, f: F) -> MapOkOrElse<Self, F, E> where
F: FnOnce(Self::Ok) -> T,
E: FnOnce(Self::Error) -> T,
Maps this future’s success value to a different value, and permits for error handling resulting in the same type. Read more
Maps this future’s error value to a different value. Read more
Executes another future after this one resolves successfully. The success value is passed to a closure to create this subsequent future. Read more
Executes another future if this one resolves to an error. The error value is passed to a closure to create this subsequent future. Read more
Do something with the success value of a future before passing it on. Read more
Do something with the error value of a future before passing it on. Read more
fn try_flatten(self) -> TryFlatten<Self, Self::Ok> where
Self::Ok: TryFuture,
<Self::Ok as TryFuture>::Error == Self::Error,
fn try_flatten(self) -> TryFlatten<Self, Self::Ok> where
Self::Ok: TryFuture,
<Self::Ok as TryFuture>::Error == Self::Error,
Flatten the execution of this future when the successful result of this future is another future. Read more
fn try_flatten_stream(self) -> TryFlattenStream<Self> where
Self::Ok: TryStream,
<Self::Ok as TryStream>::Error == Self::Error,
fn try_flatten_stream(self) -> TryFlattenStream<Self> where
Self::Ok: TryStream,
<Self::Ok as TryStream>::Error == Self::Error,
Flatten the execution of this future when the successful result of this future is a stream. Read more
fn unwrap_or_else<F>(self, f: F) -> UnwrapOrElse<Self, F> where
F: FnOnce(Self::Error) -> Self::Ok,
fn unwrap_or_else<F>(self, f: F) -> UnwrapOrElse<Self, F> where
F: FnOnce(Self::Error) -> Self::Ok,