bevy/crates/bevy_render/src/extract_resource.rs
Zachary Harrold d70595b667
Add core and alloc over std Lints (#15281)
# Objective

- Fixes #6370
- Closes #6581

## Solution

- Added the following lints to the workspace:
  - `std_instead_of_core`
  - `std_instead_of_alloc`
  - `alloc_instead_of_core`
- Used `cargo +nightly fmt` with [item level use
formatting](https://rust-lang.github.io/rustfmt/?version=v1.6.0&search=#Item%5C%3A)
to split all `use` statements into single items.
- Used `cargo clippy --workspace --all-targets --all-features --fix
--allow-dirty` to _attempt_ to resolve the new linting issues, and
intervened where the lint was unable to resolve the issue automatically
(usually due to needing an `extern crate alloc;` statement in a crate
root).
- Manually removed certain uses of `std` where negative feature gating
prevented `--all-features` from finding the offending uses.
- Used `cargo +nightly fmt` with [crate level use
formatting](https://rust-lang.github.io/rustfmt/?version=v1.6.0&search=#Crate%5C%3A)
to re-merge all `use` statements matching Bevy's previous styling.
- Manually fixed cases where the `fmt` tool could not re-merge `use`
statements due to conditional compilation attributes.

## Testing

- Ran CI locally

## Migration Guide

The MSRV is now 1.81. Please update to this version or higher.

## Notes

- This is a _massive_ change to try and push through, which is why I've
outlined the semi-automatic steps I used to create this PR, in case this
fails and someone else tries again in the future.
- Making this change has no impact on user code, but does mean Bevy
contributors will be warned to use `core` and `alloc` instead of `std`
where possible.
- This lint is a critical first step towards investigating `no_std`
options for Bevy.

---------

Co-authored-by: François Mockers <francois.mockers@vleue.com>
2024-09-27 00:59:59 +00:00

68 lines
2.3 KiB
Rust

use core::marker::PhantomData;
use bevy_app::{App, Plugin};
use bevy_ecs::prelude::*;
pub use bevy_render_macros::ExtractResource;
use crate::{Extract, ExtractSchedule, RenderApp};
/// Describes how a resource gets extracted for rendering.
///
/// Therefore the resource is transferred from the "main world" into the "render world"
/// in the [`ExtractSchedule`] step.
pub trait ExtractResource: Resource {
type Source: Resource;
/// Defines how the resource is transferred into the "render world".
fn extract_resource(source: &Self::Source) -> Self;
}
/// This plugin extracts the resources into the "render world".
///
/// Therefore it sets up the[`ExtractSchedule`] step
/// for the specified [`Resource`].
pub struct ExtractResourcePlugin<R: ExtractResource>(PhantomData<R>);
impl<R: ExtractResource> Default for ExtractResourcePlugin<R> {
fn default() -> Self {
Self(PhantomData)
}
}
impl<R: ExtractResource> Plugin for ExtractResourcePlugin<R> {
fn build(&self, app: &mut App) {
if let Some(render_app) = app.get_sub_app_mut(RenderApp) {
render_app.add_systems(ExtractSchedule, extract_resource::<R>);
} else {
bevy_utils::error_once!(
"Render app did not exist when trying to add `extract_resource` for <{}>.",
core::any::type_name::<R>()
);
}
}
}
/// This system extracts the resource of the corresponding [`Resource`] type
pub fn extract_resource<R: ExtractResource>(
mut commands: Commands,
main_resource: Extract<Option<Res<R::Source>>>,
target_resource: Option<ResMut<R>>,
) {
if let Some(main_resource) = main_resource.as_ref() {
if let Some(mut target_resource) = target_resource {
if main_resource.is_changed() {
*target_resource = R::extract_resource(main_resource);
}
} else {
#[cfg(debug_assertions)]
if !main_resource.is_added() {
bevy_utils::warn_once!(
"Removing resource {} from render world not expected, adding using `Commands`.
This may decrease performance",
core::any::type_name::<R>()
);
}
commands.insert_resource(R::extract_resource(main_resource));
}
}
}