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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
commit | 36d22d82aa202bb199967e9512281e9a53db42c9 (patch) | |
tree | 105e8c98ddea1c1e4784a60a5a6410fa416be2de /third_party/rust/async-task/README.md | |
parent | Initial commit. (diff) | |
download | firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.tar.xz firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.zip |
Adding upstream version 115.7.0esr.upstream/115.7.0esr
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'third_party/rust/async-task/README.md')
-rw-r--r-- | third_party/rust/async-task/README.md | 69 |
1 files changed, 69 insertions, 0 deletions
diff --git a/third_party/rust/async-task/README.md b/third_party/rust/async-task/README.md new file mode 100644 index 0000000000..7044c9dfd9 --- /dev/null +++ b/third_party/rust/async-task/README.md @@ -0,0 +1,69 @@ +# async-task + +[![Build](https://github.com/smol-rs/async-task/workflows/Build%20and%20test/badge.svg)]( +https://github.com/smol-rs/async-task/actions) +[![License](https://img.shields.io/badge/license-Apache--2.0_OR_MIT-blue.svg)]( +https://github.com/smol-rs/async-task) +[![Cargo](https://img.shields.io/crates/v/async-task.svg)]( +https://crates.io/crates/async-task) +[![Documentation](https://docs.rs/async-task/badge.svg)]( +https://docs.rs/async-task) + +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: + +```rust +let (sender, receiver) = flume::unbounded(); +``` + +A task is created using either `spawn()`, `spawn_local()`, or `spawn_unchecked()` which +return a `Runnable` and a `Task`: + +```rust +// 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: + +```rust +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. + +## License + +Licensed under either of + + * Apache License, Version 2.0 ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0) + * MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT) + +at your option. + +#### Contribution + +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. |