bevy/crates/bevy_app/src/terminal_ctrl_c_handler.rs
Zachary Harrold f45e78e658
Add no_std support to bevy_app (#16874)
# Objective

- Contributes to #15460

## Solution

- Added the following features:
  - `std` (default)
  - `bevy_tasks` (default)
  - `downcast ` (default)
  - `portable-atomic`
  - `critical-section`
- `downcast` and `bevy_tasks` are now optional dependencies for
`bevy_app`.

## Testing

- CI
- Personal UEFI and Raspberry Pi Pico demo applications compile and run
against this branch

## Draft Release Notes

Bevy's application framework now supports `no_std` platforms.

Following up on `bevy_ecs` gaining `no_std` support, `bevy_app` extends
the functionality available on these targets to include the powerful
`App` and `Plugin` abstractions. With this, library authors now have the
option of making their plugins `no_std` compatible, or even offering
plugins specifically to improve Bevy on certain embedded platforms!

To start making a `no_std` compatible plugin, simply disable default
features when including `bevy_app`:

```toml
[dependencies]
bevy_app = { version = "0.16", default-features = false }
```

We encourage library authors to do this anyway, as it can also help with
compile times and binary size on all platforms.

Keep an eye out for future `no_std` updates as we continue to improve
the parity between `std` and `no_std`. We look forward to seeing what
kinds of applications are now possible with Bevy!

## Notes

- `downcast-rs` is optional as it isn't compatible with
`portable-atomic`. I will investigate making a PR upstream to add
support for this functionality, as it should be very straightforward.
- In line with the `bevy_ecs` no-std-ification, I've added documentation
to all features, and grouped them as well.
- ~~Creating this PR in draft while CI runs and so I can polish before
review.~~

---------

Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
2024-12-18 22:04:45 +00:00

74 lines
2.4 KiB
Rust

use core::sync::atomic::{AtomicBool, Ordering};
use bevy_ecs::event::EventWriter;
use crate::{App, AppExit, Plugin, Update};
pub use ctrlc;
/// Indicates that all [`App`]'s should exit.
static SHOULD_EXIT: AtomicBool = AtomicBool::new(false);
/// Gracefully handles `Ctrl+C` by emitting a [`AppExit`] event. This plugin is part of the `DefaultPlugins`.
///
/// ```no_run
/// # use bevy_app::{App, NoopPluginGroup as MinimalPlugins, PluginGroup, TerminalCtrlCHandlerPlugin};
/// fn main() {
/// App::new()
/// .add_plugins(MinimalPlugins)
/// .add_plugins(TerminalCtrlCHandlerPlugin)
/// .run();
/// }
/// ```
///
/// If you want to setup your own `Ctrl+C` handler, you should call the
/// [`TerminalCtrlCHandlerPlugin::gracefully_exit`] function in your handler if you want bevy to gracefully exit.
/// ```no_run
/// # use bevy_app::{App, NoopPluginGroup as DefaultPlugins, PluginGroup, TerminalCtrlCHandlerPlugin, ctrlc};
/// fn main() {
/// // Your own `Ctrl+C` handler
/// ctrlc::set_handler(move || {
/// // Other clean up code ...
///
/// TerminalCtrlCHandlerPlugin::gracefully_exit();
/// });
///
/// App::new()
/// .add_plugins(DefaultPlugins)
/// .run();
/// }
/// ```
#[derive(Default)]
pub struct TerminalCtrlCHandlerPlugin;
impl TerminalCtrlCHandlerPlugin {
/// Sends the [`AppExit`] event to all apps using this plugin to make them gracefully exit.
pub fn gracefully_exit() {
SHOULD_EXIT.store(true, Ordering::Relaxed);
}
/// Sends a [`AppExit`] event when the user presses `Ctrl+C` on the terminal.
pub fn exit_on_flag(mut events: EventWriter<AppExit>) {
if SHOULD_EXIT.load(Ordering::Relaxed) {
events.send(AppExit::from_code(130));
}
}
}
impl Plugin for TerminalCtrlCHandlerPlugin {
fn build(&self, app: &mut App) {
let result = ctrlc::try_set_handler(move || {
Self::gracefully_exit();
});
match result {
Ok(()) => {}
Err(ctrlc::Error::MultipleHandlers) => {
log::info!("Skipping installing `Ctrl+C` handler as one was already installed. Please call `TerminalCtrlCHandlerPlugin::gracefully_exit` in your own `Ctrl+C` handler if you want Bevy to gracefully exit on `Ctrl+C`.");
}
Err(err) => log::warn!("Failed to set `Ctrl+C` handler: {err}"),
}
app.add_systems(Update, TerminalCtrlCHandlerPlugin::exit_on_flag);
}
}