| commit | 1be9e25901f7f6e523d70aa30ad0f7737cd80656 | [log] [tgz] |
|---|---|---|
| author | Android Build Coastguard Worker <[email protected]> | Fri Oct 20 03:18:44 2023 +0000 |
| committer | Android Build Coastguard Worker <[email protected]> | Fri Oct 20 03:18:44 2023 +0000 |
| tree | 7da7ef40f6c8637accffeb7b81e80b2d09d382af | |
| parent | 5c966dcb7904ed2cf81c3df744be602a0f0460c7 [diff] | |
| parent | e56fc88578c34f586108ecea7b96e46a39f39caf [diff] |
Snap for 10975086 from e56fc88578c34f586108ecea7b96e46a39f39caf to 24Q1-release Change-Id: If50fe8af598abc318a547accb188be016250c75a
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.
Licensed under either of
at your option.
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.