| commit | 8f58df2a0569b97cd7ac79755382f723676a0442 | [log] [tgz] |
|---|---|---|
| author | Bob Badour <bbadour@google.com> | Mon Mar 01 06:29:56 2021 +0000 |
| committer | Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com> | Mon Mar 01 06:29:56 2021 +0000 |
| tree | f3bce992cfababe25417990abfc285bec1191e75 | |
| parent | 0788d19f478e9c89bf278253c7c0977024b334a3 [diff] | |
| parent | 936ed472f4c5fbdc86b6a92d67393db486564240 [diff] |
[LSC] Add LOCAL_LICENSE_KINDS to external/rust/crates/async-task am: 1201213332 am: 16755c856e am: 97c43b9853 am: 936ed472f4 Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/async-task/+/1609954 MUST ONLY BE SUBMITTED BY AUTOMERGER Change-Id: I6d56cd081d24dfbc448bc1a99f9527524eec4e96
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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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.