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use crate::{
path::AssetPath, AssetIo, AssetIoError, AssetMeta, AssetServer, Assets, Handle, HandleId,
RefChangeChannel,
};
use anyhow::Error;
use anyhow::Result;
use bevy_ecs::system::{Res, ResMut};
use bevy_reflect::{TypeUuid, TypeUuidDynamic};
use bevy_utils::{BoxedFuture, HashMap};
use crossbeam_channel::{Receiver, Sender};
use downcast_rs::{impl_downcast, Downcast};
use std::path::Path;
pub trait AssetLoader: Send + Sync + 'static {
fn load<'a>(
&'a self,
bytes: &'a [u8],
load_context: &'a mut LoadContext,
) -> BoxedFuture<'a, Result<(), Error>>;
fn extensions(&self) -> &[&str];
}
pub trait Asset: TypeUuid + AssetDynamic {}
pub trait AssetDynamic: Downcast + TypeUuidDynamic + Send + Sync + 'static {}
impl_downcast!(AssetDynamic);
impl<T> Asset for T where T: TypeUuid + AssetDynamic + TypeUuidDynamic {}
impl<T> AssetDynamic for T where T: Send + Sync + 'static + TypeUuidDynamic {}
pub struct LoadedAsset<T: Asset> {
pub(crate) value: Option<T>,
pub(crate) dependencies: Vec<AssetPath<'static>>,
}
impl<T: Asset> LoadedAsset<T> {
pub fn new(value: T) -> Self {
Self {
value: Some(value),
dependencies: Vec::new(),
}
}
pub fn add_dependency(&mut self, asset_path: AssetPath) {
self.dependencies.push(asset_path.to_owned());
}
#[must_use]
pub fn with_dependency(mut self, asset_path: AssetPath) -> Self {
self.add_dependency(asset_path);
self
}
#[must_use]
pub fn with_dependencies(mut self, asset_paths: Vec<AssetPath<'static>>) -> Self {
for asset_path in asset_paths {
self.add_dependency(asset_path);
}
self
}
}
pub(crate) struct BoxedLoadedAsset {
pub(crate) value: Option<Box<dyn AssetDynamic>>,
pub(crate) dependencies: Vec<AssetPath<'static>>,
}
impl<T: Asset> From<LoadedAsset<T>> for BoxedLoadedAsset {
fn from(asset: LoadedAsset<T>) -> Self {
BoxedLoadedAsset {
value: asset
.value
.map(|value| Box::new(value) as Box<dyn AssetDynamic>),
dependencies: asset.dependencies,
}
}
}
pub struct LoadContext<'a> {
pub(crate) ref_change_channel: &'a RefChangeChannel,
pub(crate) asset_io: &'a dyn AssetIo,
pub(crate) labeled_assets: HashMap<Option<String>, BoxedLoadedAsset>,
pub(crate) path: &'a Path,
pub(crate) version: usize,
}
impl<'a> LoadContext<'a> {
pub(crate) fn new(
path: &'a Path,
ref_change_channel: &'a RefChangeChannel,
asset_io: &'a dyn AssetIo,
version: usize,
) -> Self {
Self {
ref_change_channel,
asset_io,
labeled_assets: Default::default(),
version,
path,
}
}
pub fn path(&self) -> &Path {
self.path
}
pub fn has_labeled_asset(&self, label: &str) -> bool {
self.labeled_assets.contains_key(&Some(label.to_string()))
}
pub fn set_default_asset<T: Asset>(&mut self, asset: LoadedAsset<T>) {
self.labeled_assets.insert(None, asset.into());
}
pub fn set_labeled_asset<T: Asset>(&mut self, label: &str, asset: LoadedAsset<T>) -> Handle<T> {
assert!(!label.is_empty());
self.labeled_assets
.insert(Some(label.to_string()), asset.into());
self.get_handle(AssetPath::new_ref(self.path(), Some(label)))
}
pub fn get_handle<I: Into<HandleId>, T: Asset>(&self, id: I) -> Handle<T> {
Handle::strong(id.into(), self.ref_change_channel.sender.clone())
}
pub async fn read_asset_bytes<P: AsRef<Path>>(&self, path: P) -> Result<Vec<u8>, AssetIoError> {
self.asset_io
.watch_path_for_changes(path.as_ref(), Some(self.path.to_owned()))?;
self.asset_io.load_path(path.as_ref()).await
}
pub fn get_asset_metas(&self) -> Vec<AssetMeta> {
let mut asset_metas = Vec::new();
for (label, asset) in &self.labeled_assets {
asset_metas.push(AssetMeta {
dependencies: asset.dependencies.clone(),
label: label.clone(),
type_uuid: asset.value.as_ref().unwrap().type_uuid(),
});
}
asset_metas
}
pub fn asset_io(&self) -> &dyn AssetIo {
self.asset_io
}
}
#[derive(Debug)]
pub struct AssetResult<T> {
pub asset: Box<T>,
pub id: HandleId,
pub version: usize,
}
#[derive(Debug)]
pub struct AssetLifecycleChannel<T> {
pub sender: Sender<AssetLifecycleEvent<T>>,
pub receiver: Receiver<AssetLifecycleEvent<T>>,
}
pub enum AssetLifecycleEvent<T> {
Create(AssetResult<T>),
Free(HandleId),
}
pub trait AssetLifecycle: Downcast + Send + Sync + 'static {
fn create_asset(&self, id: HandleId, asset: Box<dyn AssetDynamic>, version: usize);
fn free_asset(&self, id: HandleId);
}
impl_downcast!(AssetLifecycle);
impl<T: AssetDynamic> AssetLifecycle for AssetLifecycleChannel<T> {
fn create_asset(&self, id: HandleId, asset: Box<dyn AssetDynamic>, version: usize) {
if let Ok(asset) = asset.downcast::<T>() {
self.sender
.send(AssetLifecycleEvent::Create(AssetResult {
asset,
id,
version,
}))
.unwrap();
} else {
panic!(
"Failed to downcast asset to {}.",
std::any::type_name::<T>()
);
}
}
fn free_asset(&self, id: HandleId) {
self.sender.send(AssetLifecycleEvent::Free(id)).unwrap();
}
}
impl<T> Default for AssetLifecycleChannel<T> {
fn default() -> Self {
let (sender, receiver) = crossbeam_channel::unbounded();
AssetLifecycleChannel { sender, receiver }
}
}
pub fn update_asset_storage_system<T: Asset + AssetDynamic>(
asset_server: Res<AssetServer>,
assets: ResMut<Assets<T>>,
) {
asset_server.update_asset_storage(assets);
}