Update Android.bp by running cargo_embargo am: 85f4e209f6 am: 94eba66703

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/async-task/+/3079670

Change-Id: Ie5ab34a51a62c6a4cb42be9ad72c6d820b119490
Signed-off-by: Automerger Merge Worker <[email protected]>
tree: dbde6b41e8affb88457d0307c0ea6a6555473998
  1. benches/
  2. examples/
  3. src/
  4. tests/
  5. .cargo_vcs_info.json
  6. .gitignore
  7. Android.bp
  8. Cargo.toml
  9. Cargo.toml.orig
  10. cargo_embargo.json
  11. CHANGELOG.md
  12. LICENSE-APACHE
  13. LICENSE-MIT
  14. METADATA
  15. MODULE_LICENSE_APACHE2
  16. README.md
  17. TEST_MAPPING
README.md

async-task

Build License Cargo Documentation

Task abstraction for building executors.

To spawn a future onto an executor, we first need to allocate it on the heap and keep some state attached to it. The state indicates whether the future is ready for polling, waiting to be woken up, or completed. Such a stateful future is called a task.

All executors have a queue that holds scheduled tasks:

let (sender, receiver) = flume::unbounded();

A task is created using either spawn(), spawn_local(), or spawn_unchecked() which return a Runnable and a Task:

// A future that will be spawned.
let future = async { 1 + 2 };

// A function that schedules the task when it gets woken up.
let schedule = move |runnable| sender.send(runnable).unwrap();

// Construct a task.
let (runnable, task) = async_task::spawn(future, schedule);

// Push the task into the queue by invoking its schedule function.
runnable.schedule();

The Runnable is used to poll the task's future, and the Task is used to await its output.

Finally, we need a loop that takes scheduled tasks from the queue and runs them:

for runnable in receiver {
    runnable.run();
}

Method run() polls the task's future once. Then, the Runnable vanishes and only reappears when its Waker wakes the task, thus scheduling it to be run again.

License

Licensed under either of

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.