| commit | a4f6862903033acc550372d92e9ba4ac506c80aa | [log] [tgz] |
|---|---|---|
| author | Matthew Maurer <mmaurer@google.com> | Tue May 31 16:45:41 2022 +0000 |
| committer | Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com> | Tue May 31 16:45:41 2022 +0000 |
| tree | 6119b3a0a16c22f62f0078cecb11493361e99954 | |
| parent | e12d2cfcff2456cbe3c7ff1974ff288b7c1c381e [diff] | |
| parent | a7c63afe56cfa31e153525fd05ec3371957baab0 [diff] |
Update TEST_MAPPING am: 698295efe0 am: a7c63afe56 Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/async-task/+/2106888 Change-Id: Ibade889547a5a6cc99d170305f5b9b5902af4afe Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>
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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