557ab9897a
# Objective - In the large majority of cases, users were calling `.unwrap()` immediately after `.get_resource`. - Attempting to add more helpful error messages here resulted in endless manual boilerplate (see #3899 and the linked PRs). ## Solution - Add an infallible variant named `.resource` and so on. - Use these infallible variants over `.get_resource().unwrap()` across the code base. ## Notes I did not provide equivalent methods on `WorldCell`, in favor of removing it entirely in #3939. ## Migration Guide Infallible variants of `.get_resource` have been added that implicitly panic, rather than needing to be unwrapped. Replace `world.get_resource::<Foo>().unwrap()` with `world.resource::<Foo>()`. ## Impact - `.unwrap` search results before: 1084 - `.unwrap` search results after: 942 - internal `unwrap_or_else` calls added: 4 - trivial unwrap calls removed from tests and code: 146 - uses of the new `try_get_resource` API: 11 - percentage of the time the unwrapping API was used internally: 93%
94 lines
3.0 KiB
Rust
94 lines
3.0 KiB
Rust
use bevy::{
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asset::{AssetIo, AssetIoError},
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prelude::*,
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utils::BoxedFuture,
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};
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use std::path::{Path, PathBuf};
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/// A custom asset io implementation that simply defers to the platform default
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/// implementation.
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///
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/// This can be used as a starting point for developing a useful implementation
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/// that can defer to the default when needed.
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struct CustomAssetIo(Box<dyn AssetIo>);
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impl AssetIo for CustomAssetIo {
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fn load_path<'a>(&'a self, path: &'a Path) -> BoxedFuture<'a, Result<Vec<u8>, AssetIoError>> {
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info!("load_path({:?})", path);
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self.0.load_path(path)
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}
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fn read_directory(
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&self,
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path: &Path,
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) -> Result<Box<dyn Iterator<Item = PathBuf>>, AssetIoError> {
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info!("read_directory({:?})", path);
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self.0.read_directory(path)
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}
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fn is_directory(&self, path: &Path) -> bool {
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info!("is_directory({:?})", path);
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self.0.is_directory(path)
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}
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fn watch_path_for_changes(&self, path: &Path) -> Result<(), AssetIoError> {
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info!("watch_path_for_changes({:?})", path);
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self.0.watch_path_for_changes(path)
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}
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fn watch_for_changes(&self) -> Result<(), AssetIoError> {
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info!("watch_for_changes()");
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self.0.watch_for_changes()
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}
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}
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/// A plugin used to execute the override of the asset io
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struct CustomAssetIoPlugin;
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impl Plugin for CustomAssetIoPlugin {
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fn build(&self, app: &mut App) {
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// must get a hold of the task pool in order to create the asset server
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let task_pool = app.world.resource::<bevy::tasks::IoTaskPool>().0.clone();
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let asset_io = {
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// the platform default asset io requires a reference to the app
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// builder to find its configuration
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let default_io = bevy::asset::create_platform_default_asset_io(app);
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// create the custom asset io instance
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CustomAssetIo(default_io)
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};
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// the asset server is constructed and added the resource manager
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app.insert_resource(AssetServer::new(asset_io, task_pool));
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}
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}
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fn main() {
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App::new()
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.add_plugins_with(DefaultPlugins, |group| {
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// the custom asset io plugin must be inserted in-between the
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// `CorePlugin' and `AssetPlugin`. It needs to be after the
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// CorePlugin, so that the IO task pool has already been constructed.
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// And it must be before the `AssetPlugin` so that the asset plugin
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// doesn't create another instance of an asset server. In general,
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// the AssetPlugin should still run so that other aspects of the
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// asset system are initialized correctly.
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group.add_before::<bevy::asset::AssetPlugin, _>(CustomAssetIoPlugin)
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})
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.add_startup_system(setup)
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.run();
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}
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fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
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commands.spawn_bundle(OrthographicCameraBundle::new_2d());
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commands.spawn_bundle(SpriteBundle {
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texture: asset_server.load("branding/icon.png"),
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..Default::default()
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});
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}
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