| commit | a9529cb5b49b04c896de34af15fa4b4640d79150 | [log] [tgz] |
|---|---|---|
| author | Andrew Walbran <[email protected]> | Thu Oct 19 20:37:24 2023 +0000 |
| committer | Automerger Merge Worker <[email protected]> | Thu Oct 19 20:37:24 2023 +0000 |
| tree | 7da7ef40f6c8637accffeb7b81e80b2d09d382af | |
| parent | e56fc88578c34f586108ecea7b96e46a39f39caf [diff] | |
| parent | 13ace6989b942f8d5dcd177ddedbbe9a3fc622a7 [diff] |
Migrate to cargo_embargo. am: 93b21ad4eb am: 2ad85522c7 am: 13ace6989b Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/async-task/+/2796114 Change-Id: Idba27fd460ccca5a7597fde1b50402691dad348a Signed-off-by: Automerger Merge Worker <[email protected]>
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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