| commit | 48751b113f43df9535a1bf8ebfb3bdf8872b7444 | [log] [tgz] |
|---|---|---|
| author | Android Build Coastguard Worker <[email protected]> | Tue Aug 20 17:55:37 2024 +0000 |
| committer | Android Build Coastguard Worker <[email protected]> | Tue Aug 20 17:55:37 2024 +0000 |
| tree | 592703c6d9f929b9ca10de66603dcb156beb8f20 | |
| parent | 737a25a72fb45cba5433fe52ccec31b269f58c87 [diff] | |
| parent | 656da64d57149603e5eb96f6e1b49208f0b96fd9 [diff] |
Snap for 12252487 from 656da64d57149603e5eb96f6e1b49208f0b96fd9 to simpleperf-release Change-Id: I90bc7878e6b9671ddeaa967bfea2280d725de9a7
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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