| commit | e06ef4450fc5da9b4c556f21bc9bc31b4283de99 | [log] [tgz] |
|---|---|---|
| author | Jorge E. Moreira <[email protected]> | Thu Feb 18 00:48:12 2021 +0000 |
| committer | Automerger Merge Worker <[email protected]> | Thu Feb 18 00:48:12 2021 +0000 |
| tree | 5f1447c1519986bb07c065d16cb4b2d381acab14 | |
| parent | 069c6e09c4bdccb66d8a8304ab7cd461d5b4e460 [diff] | |
| parent | 99ac45aa74d283eb31b653275f72864557f75465 [diff] |
Add Android.bp am: 99ac45aa74 Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/async-task/+/1590853 MUST ONLY BE SUBMITTED BY AUTOMERGER Change-Id: I24bd14b61ce4290e7c2a551b76effacdfe62f400
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.
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