| commit | 936ed472f4c5fbdc86b6a92d67393db486564240 | [log] [tgz] |
|---|---|---|
| author | Bob Badour <[email protected]> | Mon Mar 01 05:37:58 2021 +0000 |
| committer | Automerger Merge Worker <[email protected]> | Mon Mar 01 05:37:58 2021 +0000 |
| tree | f3bce992cfababe25417990abfc285bec1191e75 | |
| parent | 82699331f549b31b34b278453ecb0c438b15359d [diff] | |
| parent | 97c43b985349753ded3e89baae351a6f3e3c8d17 [diff] |
[LSC] Add LOCAL_LICENSE_KINDS to external/rust/crates/async-task am: 1201213332 am: 16755c856e am: 97c43b9853 Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/async-task/+/1609954 MUST ONLY BE SUBMITTED BY AUTOMERGER Change-Id: If2d25155205103da57612e38c87a6698ba874fd6
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.