1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305
//! Implementations of the builder-pattern used for loading dependent assets via
//! [`LoadContext::loader`].
use crate::{
io::Reader,
meta::{meta_transform_settings, AssetMetaDyn, MetaTransform, Settings},
Asset, AssetLoadError, AssetPath, ErasedAssetLoader, ErasedLoadedAsset, Handle, LoadContext,
LoadDirectError, LoadedAsset, LoadedUntypedAsset,
};
use std::any::TypeId;
use std::sync::Arc;
// Utility type for handling the sources of reader references
enum ReaderRef<'a, 'b> {
Borrowed(&'a mut Reader<'b>),
Boxed(Box<Reader<'b>>),
}
impl<'a, 'b> ReaderRef<'a, 'b> {
pub fn as_mut(&mut self) -> &mut Reader {
match self {
ReaderRef::Borrowed(r) => r,
ReaderRef::Boxed(b) => &mut *b,
}
}
}
/// A builder for loading nested assets inside a `LoadContext`.
///
/// # Lifetimes
/// - `ctx`: the lifetime of the associated [`AssetServer`] reference
/// - `builder`: the lifetime of the temporary builder structs
pub struct NestedLoader<'ctx, 'builder> {
load_context: &'builder mut LoadContext<'ctx>,
meta_transform: Option<MetaTransform>,
asset_type_id: Option<TypeId>,
}
impl<'ctx, 'builder> NestedLoader<'ctx, 'builder> {
pub(crate) fn new(
load_context: &'builder mut LoadContext<'ctx>,
) -> NestedLoader<'ctx, 'builder> {
NestedLoader {
load_context,
meta_transform: None,
asset_type_id: None,
}
}
fn with_transform(
mut self,
transform: impl Fn(&mut dyn AssetMetaDyn) + Send + Sync + 'static,
) -> Self {
if let Some(prev_transform) = self.meta_transform {
self.meta_transform = Some(Box::new(move |meta| {
prev_transform(meta);
transform(meta);
}));
} else {
self.meta_transform = Some(Box::new(transform));
}
self
}
/// Configure the settings used to load the asset.
///
/// If the settings type `S` does not match the settings expected by `A`'s asset loader, an error will be printed to the log
/// and the asset load will fail.
#[must_use]
pub fn with_settings<S: Settings>(
self,
settings: impl Fn(&mut S) + Send + Sync + 'static,
) -> Self {
self.with_transform(move |meta| meta_transform_settings(meta, &settings))
}
/// Specify the output asset type.
#[must_use]
pub fn with_asset_type<A: Asset>(mut self) -> Self {
self.asset_type_id = Some(TypeId::of::<A>());
self
}
/// Specify the output asset type.
#[must_use]
pub fn with_asset_type_id(mut self, asset_type_id: TypeId) -> Self {
self.asset_type_id = Some(asset_type_id);
self
}
/// Load assets directly, rather than creating handles.
#[must_use]
pub fn direct<'c>(self) -> DirectNestedLoader<'ctx, 'builder, 'c> {
DirectNestedLoader {
base: self,
reader: None,
}
}
/// Load assets without static type information.
///
/// If you need to specify the type of asset, but cannot do it statically,
/// use `.with_asset_type_id()`.
#[must_use]
pub fn untyped(self) -> UntypedNestedLoader<'ctx, 'builder> {
UntypedNestedLoader { base: self }
}
/// Retrieves a handle for the asset at the given path and adds that path as a dependency of the asset.
/// If the current context is a normal [`AssetServer::load`], an actual asset load will be kicked off immediately, which ensures the load happens
/// as soon as possible.
/// "Normal loads" kicked from within a normal Bevy App will generally configure the context to kick off loads immediately.
/// If the current context is configured to not load dependencies automatically (ex: [`AssetProcessor`](crate::processor::AssetProcessor)),
/// a load will not be kicked off automatically. It is then the calling context's responsibility to begin a load if necessary.
pub fn load<'c, A: Asset>(self, path: impl Into<AssetPath<'c>>) -> Handle<A> {
let path = path.into().to_owned();
let handle = if self.load_context.should_load_dependencies {
self.load_context
.asset_server
.load_with_meta_transform(path, self.meta_transform, ())
} else {
self.load_context
.asset_server
.get_or_create_path_handle(path, None)
};
self.load_context.dependencies.insert(handle.id().untyped());
handle
}
}
/// A builder for loading untyped nested assets inside a [`LoadContext`].
///
/// # Lifetimes
/// - `ctx`: the lifetime of the associated [`AssetServer`] reference
/// - `builder`: the lifetime of the temporary builder structs
pub struct UntypedNestedLoader<'ctx, 'builder> {
base: NestedLoader<'ctx, 'builder>,
}
impl<'ctx, 'builder> UntypedNestedLoader<'ctx, 'builder> {
/// Retrieves a handle for the asset at the given path and adds that path as a dependency of the asset without knowing its type.
pub fn load<'p>(self, path: impl Into<AssetPath<'p>>) -> Handle<LoadedUntypedAsset> {
let path = path.into().to_owned();
let handle = if self.base.load_context.should_load_dependencies {
self.base
.load_context
.asset_server
.load_untyped_with_meta_transform(path, self.base.meta_transform)
} else {
self.base
.load_context
.asset_server
.get_or_create_path_handle(path, self.base.meta_transform)
};
self.base
.load_context
.dependencies
.insert(handle.id().untyped());
handle
}
}
/// A builder for directly loading nested assets inside a `LoadContext`.
///
/// # Lifetimes
/// - `ctx`: the lifetime of the associated [`AssetServer`] reference
/// - `builder`: the lifetime of the temporary builder structs
/// - `reader`: the lifetime of the [`Reader`] reference used to read the asset data
pub struct DirectNestedLoader<'ctx, 'builder, 'reader> {
base: NestedLoader<'ctx, 'builder>,
reader: Option<&'builder mut Reader<'reader>>,
}
impl<'ctx: 'reader, 'builder, 'reader> DirectNestedLoader<'ctx, 'builder, 'reader> {
/// Specify the reader to use to read the asset data.
#[must_use]
pub fn with_reader(mut self, reader: &'builder mut Reader<'reader>) -> Self {
self.reader = Some(reader);
self
}
/// Load the asset without providing static type information.
///
/// If you need to specify the type of asset, but cannot do it statically,
/// use `.with_asset_type_id()`.
#[must_use]
pub fn untyped(self) -> UntypedDirectNestedLoader<'ctx, 'builder, 'reader> {
UntypedDirectNestedLoader { base: self }
}
async fn load_internal(
self,
path: &AssetPath<'static>,
) -> Result<(Arc<dyn ErasedAssetLoader>, ErasedLoadedAsset), LoadDirectError> {
let (mut meta, loader, mut reader) = if let Some(reader) = self.reader {
let loader = if let Some(asset_type_id) = self.base.asset_type_id {
self.base
.load_context
.asset_server
.get_asset_loader_with_asset_type_id(asset_type_id)
.await
.map_err(|error| LoadDirectError {
dependency: path.clone(),
error: error.into(),
})?
} else {
self.base
.load_context
.asset_server
.get_path_asset_loader(path)
.await
.map_err(|error| LoadDirectError {
dependency: path.clone(),
error: error.into(),
})?
};
let meta = loader.default_meta();
(meta, loader, ReaderRef::Borrowed(reader))
} else {
let (meta, loader, reader) = self
.base
.load_context
.asset_server
.get_meta_loader_and_reader(path, self.base.asset_type_id)
.await
.map_err(|error| LoadDirectError {
dependency: path.clone(),
error,
})?;
(meta, loader, ReaderRef::Boxed(reader))
};
if let Some(meta_transform) = self.base.meta_transform {
meta_transform(&mut *meta);
}
let asset = self
.base
.load_context
.load_direct_internal(path.clone(), meta, &*loader, reader.as_mut())
.await?;
Ok((loader, asset))
}
/// Loads the asset at the given `path` directly. This is an async function that will wait until the asset is fully loaded before
/// returning. Use this if you need the _value_ of another asset in order to load the current asset. For example, if you are
/// deriving a new asset from the referenced asset, or you are building a collection of assets. This will add the `path` as a
/// "load dependency".
///
/// If the current loader is used in a [`Process`] "asset preprocessor", such as a [`LoadTransformAndSave`] preprocessor,
/// changing a "load dependency" will result in re-processing of the asset.
///
/// [`Process`]: crate::processor::Process
/// [`LoadTransformAndSave`]: crate::processor::LoadTransformAndSave
pub async fn load<'p, A: Asset>(
mut self,
path: impl Into<AssetPath<'p>>,
) -> Result<LoadedAsset<A>, LoadDirectError> {
self.base.asset_type_id = Some(TypeId::of::<A>());
let path = path.into().into_owned();
self.load_internal(&path)
.await
.and_then(move |(loader, untyped_asset)| {
untyped_asset.downcast::<A>().map_err(|_| LoadDirectError {
dependency: path.clone(),
error: AssetLoadError::RequestedHandleTypeMismatch {
path,
requested: TypeId::of::<A>(),
actual_asset_name: loader.asset_type_name(),
loader_name: loader.type_name(),
},
})
})
}
}
/// A builder for directly loading untyped nested assets inside a `LoadContext`.
///
/// # Lifetimes
/// - `ctx`: the lifetime of the associated [`AssetServer`] reference
/// - `builder`: the lifetime of the temporary builder structs
/// - `reader`: the lifetime of the [`Reader`] reference used to read the asset data
pub struct UntypedDirectNestedLoader<'ctx, 'builder, 'reader> {
base: DirectNestedLoader<'ctx, 'builder, 'reader>,
}
impl<'ctx: 'reader, 'builder, 'reader> UntypedDirectNestedLoader<'ctx, 'builder, 'reader> {
/// Loads the asset at the given `path` directly. This is an async function that will wait until the asset is fully loaded before
/// returning. Use this if you need the _value_ of another asset in order to load the current asset. For example, if you are
/// deriving a new asset from the referenced asset, or you are building a collection of assets. This will add the `path` as a
/// "load dependency".
///
/// If the current loader is used in a [`Process`] "asset preprocessor", such as a [`LoadTransformAndSave`] preprocessor,
/// changing a "load dependency" will result in re-processing of the asset.
///
/// [`Process`]: crate::processor::Process
/// [`LoadTransformAndSave`]: crate::processor::LoadTransformAndSave
pub async fn load<'p>(
self,
path: impl Into<AssetPath<'p>>,
) -> Result<ErasedLoadedAsset, LoadDirectError> {
let path = path.into().into_owned();
self.base.load_internal(&path).await.map(|(_, asset)| asset)
}
}