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
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
use crate::{
    io::{AssetReaderError, MissingAssetSourceError, MissingProcessedAssetReaderError, Reader},
    loader_builders::NestedLoader,
    meta::{AssetHash, AssetMeta, AssetMetaDyn, ProcessedInfoMinimal, Settings},
    path::AssetPath,
    Asset, AssetLoadError, AssetServer, AssetServerMode, Assets, Handle, UntypedAssetId,
    UntypedHandle,
};
use bevy_ecs::world::World;
use bevy_utils::{BoxedFuture, ConditionalSendFuture, CowArc, HashMap, HashSet};
use downcast_rs::{impl_downcast, Downcast};
use futures_lite::AsyncReadExt;
use ron::error::SpannedError;
use serde::{Deserialize, Serialize};
use std::{
    any::{Any, TypeId},
    path::{Path, PathBuf},
};
use thiserror::Error;

/// Loads an [`Asset`] from a given byte [`Reader`]. This can accept [`AssetLoader::Settings`], which configure how the [`Asset`]
/// should be loaded.
pub trait AssetLoader: Send + Sync + 'static {
    /// The top level [`Asset`] loaded by this [`AssetLoader`].
    type Asset: crate::Asset;
    /// The settings type used by this [`AssetLoader`].
    type Settings: Settings + Default + Serialize + for<'a> Deserialize<'a>;
    /// The type of [error](`std::error::Error`) which could be encountered by this loader.
    type Error: Into<Box<dyn std::error::Error + Send + Sync + 'static>>;
    /// Asynchronously loads [`AssetLoader::Asset`] (and any other labeled assets) from the bytes provided by [`Reader`].
    fn load<'a>(
        &'a self,
        reader: &'a mut Reader,
        settings: &'a Self::Settings,
        load_context: &'a mut LoadContext,
    ) -> impl ConditionalSendFuture<Output = Result<Self::Asset, Self::Error>>;

    /// Returns a list of extensions supported by this [`AssetLoader`], without the preceding dot.
    /// Note that users of this [`AssetLoader`] may choose to load files with a non-matching extension.
    fn extensions(&self) -> &[&str] {
        &[]
    }
}

/// Provides type-erased access to an [`AssetLoader`].
pub trait ErasedAssetLoader: Send + Sync + 'static {
    /// Asynchronously loads the asset(s) from the bytes provided by [`Reader`].
    fn load<'a>(
        &'a self,
        reader: &'a mut Reader,
        meta: Box<dyn AssetMetaDyn>,
        load_context: LoadContext<'a>,
    ) -> BoxedFuture<
        'a,
        Result<ErasedLoadedAsset, Box<dyn std::error::Error + Send + Sync + 'static>>,
    >;

    /// Returns a list of extensions supported by this asset loader, without the preceding dot.
    fn extensions(&self) -> &[&str];
    /// Deserializes metadata from the input `meta` bytes into the appropriate type (erased as [`Box<dyn AssetMetaDyn>`]).
    fn deserialize_meta(&self, meta: &[u8]) -> Result<Box<dyn AssetMetaDyn>, DeserializeMetaError>;
    /// Returns the default meta value for the [`AssetLoader`] (erased as [`Box<dyn AssetMetaDyn>`]).
    fn default_meta(&self) -> Box<dyn AssetMetaDyn>;
    /// Returns the type name of the [`AssetLoader`].
    fn type_name(&self) -> &'static str;
    /// Returns the [`TypeId`] of the [`AssetLoader`].
    fn type_id(&self) -> TypeId;
    /// Returns the type name of the top-level [`Asset`] loaded by the [`AssetLoader`].
    fn asset_type_name(&self) -> &'static str;
    /// Returns the [`TypeId`] of the top-level [`Asset`] loaded by the [`AssetLoader`].
    fn asset_type_id(&self) -> TypeId;
}

impl<L> ErasedAssetLoader for L
where
    L: AssetLoader + Send + Sync,
{
    /// Processes the asset in an asynchronous closure.
    fn load<'a>(
        &'a self,
        reader: &'a mut Reader,
        meta: Box<dyn AssetMetaDyn>,
        mut load_context: LoadContext<'a>,
    ) -> BoxedFuture<
        'a,
        Result<ErasedLoadedAsset, Box<dyn std::error::Error + Send + Sync + 'static>>,
    > {
        Box::pin(async move {
            let settings = meta
                .loader_settings()
                .expect("Loader settings should exist")
                .downcast_ref::<L::Settings>()
                .expect("AssetLoader settings should match the loader type");
            let asset = <L as AssetLoader>::load(self, reader, settings, &mut load_context)
                .await
                .map_err(|error| error.into())?;
            Ok(load_context.finish(asset, Some(meta)).into())
        })
    }

    fn extensions(&self) -> &[&str] {
        <L as AssetLoader>::extensions(self)
    }

    fn deserialize_meta(&self, meta: &[u8]) -> Result<Box<dyn AssetMetaDyn>, DeserializeMetaError> {
        let meta = AssetMeta::<L, ()>::deserialize(meta)?;
        Ok(Box::new(meta))
    }

    fn default_meta(&self) -> Box<dyn AssetMetaDyn> {
        Box::new(AssetMeta::<L, ()>::new(crate::meta::AssetAction::Load {
            loader: self.type_name().to_string(),
            settings: L::Settings::default(),
        }))
    }

    fn type_name(&self) -> &'static str {
        std::any::type_name::<L>()
    }

    fn type_id(&self) -> TypeId {
        TypeId::of::<L>()
    }

    fn asset_type_name(&self) -> &'static str {
        std::any::type_name::<L::Asset>()
    }

    fn asset_type_id(&self) -> TypeId {
        TypeId::of::<L::Asset>()
    }
}

pub(crate) struct LabeledAsset {
    pub(crate) asset: ErasedLoadedAsset,
    pub(crate) handle: UntypedHandle,
}

/// The successful result of an [`AssetLoader::load`] call. This contains the loaded "root" asset and any other "labeled" assets produced
/// by the loader. It also holds the input [`AssetMeta`] (if it exists) and tracks dependencies:
/// * normal dependencies: dependencies that must be loaded as part of this asset load (ex: assets a given asset has handles to).
/// * Loader dependencies: dependencies whose actual asset values are used during the load process
pub struct LoadedAsset<A: Asset> {
    pub(crate) value: A,
    pub(crate) dependencies: HashSet<UntypedAssetId>,
    pub(crate) loader_dependencies: HashMap<AssetPath<'static>, AssetHash>,
    pub(crate) labeled_assets: HashMap<CowArc<'static, str>, LabeledAsset>,
    pub(crate) meta: Option<Box<dyn AssetMetaDyn>>,
}

impl<A: Asset> LoadedAsset<A> {
    /// Create a new loaded asset. This will use [`VisitAssetDependencies`](crate::VisitAssetDependencies) to populate `dependencies`.
    pub fn new_with_dependencies(value: A, meta: Option<Box<dyn AssetMetaDyn>>) -> Self {
        let mut dependencies = HashSet::new();
        value.visit_dependencies(&mut |id| {
            dependencies.insert(id);
        });
        LoadedAsset {
            value,
            dependencies,
            loader_dependencies: HashMap::default(),
            labeled_assets: HashMap::default(),
            meta,
        }
    }

    /// Cast (and take ownership) of the [`Asset`] value of the given type.
    pub fn take(self) -> A {
        self.value
    }

    /// Retrieves a reference to the internal [`Asset`] type.
    pub fn get(&self) -> &A {
        &self.value
    }

    /// Returns the [`ErasedLoadedAsset`] for the given label, if it exists.
    pub fn get_labeled(
        &self,
        label: impl Into<CowArc<'static, str>>,
    ) -> Option<&ErasedLoadedAsset> {
        self.labeled_assets.get(&label.into()).map(|a| &a.asset)
    }

    /// Iterate over all labels for "labeled assets" in the loaded asset
    pub fn iter_labels(&self) -> impl Iterator<Item = &str> {
        self.labeled_assets.keys().map(|s| &**s)
    }
}

impl<A: Asset> From<A> for LoadedAsset<A> {
    fn from(asset: A) -> Self {
        LoadedAsset::new_with_dependencies(asset, None)
    }
}

/// A "type erased / boxed" counterpart to [`LoadedAsset`]. This is used in places where the loaded type is not statically known.
pub struct ErasedLoadedAsset {
    pub(crate) value: Box<dyn AssetContainer>,
    pub(crate) dependencies: HashSet<UntypedAssetId>,
    pub(crate) loader_dependencies: HashMap<AssetPath<'static>, AssetHash>,
    pub(crate) labeled_assets: HashMap<CowArc<'static, str>, LabeledAsset>,
    pub(crate) meta: Option<Box<dyn AssetMetaDyn>>,
}

impl<A: Asset> From<LoadedAsset<A>> for ErasedLoadedAsset {
    fn from(asset: LoadedAsset<A>) -> Self {
        ErasedLoadedAsset {
            value: Box::new(asset.value),
            dependencies: asset.dependencies,
            loader_dependencies: asset.loader_dependencies,
            labeled_assets: asset.labeled_assets,
            meta: asset.meta,
        }
    }
}

impl ErasedLoadedAsset {
    /// Cast (and take ownership) of the [`Asset`] value of the given type. This will return [`Some`] if
    /// the stored type matches `A` and [`None`] if it does not.
    pub fn take<A: Asset>(self) -> Option<A> {
        self.value.downcast::<A>().map(|a| *a).ok()
    }

    /// Retrieves a reference to the internal [`Asset`] type, if it matches the type `A`. Otherwise returns [`None`].
    pub fn get<A: Asset>(&self) -> Option<&A> {
        self.value.downcast_ref::<A>()
    }

    /// Retrieves the [`TypeId`] of the stored [`Asset`] type.
    pub fn asset_type_id(&self) -> TypeId {
        (*self.value).type_id()
    }

    /// Retrieves the `type_name` of the stored [`Asset`] type.
    pub fn asset_type_name(&self) -> &'static str {
        self.value.asset_type_name()
    }

    /// Returns the [`ErasedLoadedAsset`] for the given label, if it exists.
    pub fn get_labeled(
        &self,
        label: impl Into<CowArc<'static, str>>,
    ) -> Option<&ErasedLoadedAsset> {
        self.labeled_assets.get(&label.into()).map(|a| &a.asset)
    }

    /// Iterate over all labels for "labeled assets" in the loaded asset
    pub fn iter_labels(&self) -> impl Iterator<Item = &str> {
        self.labeled_assets.keys().map(|s| &**s)
    }

    /// Cast this loaded asset as the given type. If the type does not match,
    /// the original type-erased asset is returned.
    #[allow(clippy::result_large_err)]
    pub fn downcast<A: Asset>(mut self) -> Result<LoadedAsset<A>, ErasedLoadedAsset> {
        match self.value.downcast::<A>() {
            Ok(value) => Ok(LoadedAsset {
                value: *value,
                dependencies: self.dependencies,
                loader_dependencies: self.loader_dependencies,
                labeled_assets: self.labeled_assets,
                meta: self.meta,
            }),
            Err(value) => {
                self.value = value;
                Err(self)
            }
        }
    }
}

/// A type erased container for an [`Asset`] value that is capable of inserting the [`Asset`] into a [`World`]'s [`Assets`] collection.
pub trait AssetContainer: Downcast + Any + Send + Sync + 'static {
    fn insert(self: Box<Self>, id: UntypedAssetId, world: &mut World);
    fn asset_type_name(&self) -> &'static str;
}

impl_downcast!(AssetContainer);

impl<A: Asset> AssetContainer for A {
    fn insert(self: Box<Self>, id: UntypedAssetId, world: &mut World) {
        world.resource_mut::<Assets<A>>().insert(id.typed(), *self);
    }

    fn asset_type_name(&self) -> &'static str {
        std::any::type_name::<A>()
    }
}

/// An error that occurs when attempting to call [`LoadContext::load_direct`]
#[derive(Error, Debug)]
#[error("Failed to load dependency {dependency:?} {error}")]
pub struct LoadDirectError {
    pub dependency: AssetPath<'static>,
    pub error: AssetLoadError,
}

/// An error that occurs while deserializing [`AssetMeta`].
#[derive(Error, Debug, Clone, PartialEq, Eq)]
pub enum DeserializeMetaError {
    #[error("Failed to deserialize asset meta: {0:?}")]
    DeserializeSettings(#[from] SpannedError),
    #[error("Failed to deserialize minimal asset meta: {0:?}")]
    DeserializeMinimal(SpannedError),
}

/// A context that provides access to assets in [`AssetLoader`]s, tracks dependencies, and collects asset load state.
/// Any asset state accessed by [`LoadContext`] will be tracked and stored for use in dependency events and asset preprocessing.
pub struct LoadContext<'a> {
    pub(crate) asset_server: &'a AssetServer,
    pub(crate) should_load_dependencies: bool,
    populate_hashes: bool,
    asset_path: AssetPath<'static>,
    pub(crate) dependencies: HashSet<UntypedAssetId>,
    /// Direct dependencies used by this loader.
    pub(crate) loader_dependencies: HashMap<AssetPath<'static>, AssetHash>,
    pub(crate) labeled_assets: HashMap<CowArc<'static, str>, LabeledAsset>,
}

impl<'a> LoadContext<'a> {
    /// Creates a new [`LoadContext`] instance.
    pub(crate) fn new(
        asset_server: &'a AssetServer,
        asset_path: AssetPath<'static>,
        should_load_dependencies: bool,
        populate_hashes: bool,
    ) -> Self {
        Self {
            asset_server,
            asset_path,
            populate_hashes,
            should_load_dependencies,
            dependencies: HashSet::default(),
            loader_dependencies: HashMap::default(),
            labeled_assets: HashMap::default(),
        }
    }

    /// Begins a new labeled asset load. Use the returned [`LoadContext`] to load
    /// dependencies for the new asset and call [`LoadContext::finish`] to finalize the asset load.
    /// When finished, make sure you call [`LoadContext::add_labeled_asset`] to add the results back to the parent
    /// context.
    /// Prefer [`LoadContext::labeled_asset_scope`] when possible, which will automatically add
    /// the labeled [`LoadContext`] back to the parent context.
    /// [`LoadContext::begin_labeled_asset`] exists largely to enable parallel asset loading.
    ///
    /// See [`AssetPath`] for more on labeled assets.
    ///
    /// ```no_run
    /// # use bevy_asset::{Asset, LoadContext};
    /// # use bevy_reflect::TypePath;
    /// # #[derive(Asset, TypePath, Default)]
    /// # struct Image;
    /// # let load_context: LoadContext = panic!();
    /// let mut handles = Vec::new();
    /// for i in 0..2 {
    ///     let mut labeled = load_context.begin_labeled_asset();
    ///     handles.push(std::thread::spawn(move || {
    ///         (i.to_string(), labeled.finish(Image::default(), None))
    ///     }));
    /// }

    /// for handle in handles {
    ///     let (label, loaded_asset) = handle.join().unwrap();
    ///     load_context.add_loaded_labeled_asset(label, loaded_asset);
    /// }
    /// ```
    pub fn begin_labeled_asset(&self) -> LoadContext {
        LoadContext::new(
            self.asset_server,
            self.asset_path.clone(),
            self.should_load_dependencies,
            self.populate_hashes,
        )
    }

    /// Creates a new [`LoadContext`] for the given `label`. The `load` function is responsible for loading an [`Asset`] of
    /// type `A`. `load` will be called immediately and the result will be used to finalize the [`LoadContext`], resulting in a new
    /// [`LoadedAsset`], which is registered under the `label` label.
    ///
    /// This exists to remove the need to manually call [`LoadContext::begin_labeled_asset`] and then manually register the
    /// result with [`LoadContext::add_labeled_asset`].
    ///
    /// See [`AssetPath`] for more on labeled assets.
    pub fn labeled_asset_scope<A: Asset>(
        &mut self,
        label: String,
        load: impl FnOnce(&mut LoadContext) -> A,
    ) -> Handle<A> {
        let mut context = self.begin_labeled_asset();
        let asset = load(&mut context);
        let loaded_asset = context.finish(asset, None);
        self.add_loaded_labeled_asset(label, loaded_asset)
    }

    /// This will add the given `asset` as a "labeled [`Asset`]" with the `label` label.
    ///
    /// # Warning
    ///
    /// This will not assign dependencies to the given `asset`. If adding an asset
    /// with dependencies generated from calls such as [`LoadContext::load`], use
    /// [`LoadContext::labeled_asset_scope`] or [`LoadContext::begin_labeled_asset`] to generate a
    /// new [`LoadContext`] to track the dependencies for the labeled asset.
    ///
    /// See [`AssetPath`] for more on labeled assets.
    pub fn add_labeled_asset<A: Asset>(&mut self, label: String, asset: A) -> Handle<A> {
        self.labeled_asset_scope(label, |_| asset)
    }

    /// Add a [`LoadedAsset`] that is a "labeled sub asset" of the root path of this load context.
    /// This can be used in combination with [`LoadContext::begin_labeled_asset`] to parallelize
    /// sub asset loading.
    ///
    /// See [`AssetPath`] for more on labeled assets.
    pub fn add_loaded_labeled_asset<A: Asset>(
        &mut self,
        label: impl Into<CowArc<'static, str>>,
        loaded_asset: LoadedAsset<A>,
    ) -> Handle<A> {
        let label = label.into();
        let loaded_asset: ErasedLoadedAsset = loaded_asset.into();
        let labeled_path = self.asset_path.clone().with_label(label.clone());
        let handle = self
            .asset_server
            .get_or_create_path_handle(labeled_path, None);
        self.labeled_assets.insert(
            label,
            LabeledAsset {
                asset: loaded_asset,
                handle: handle.clone().untyped(),
            },
        );
        handle
    }

    /// Returns `true` if an asset with the label `label` exists in this context.
    ///
    /// See [`AssetPath`] for more on labeled assets.
    pub fn has_labeled_asset<'b>(&self, label: impl Into<CowArc<'b, str>>) -> bool {
        let path = self.asset_path.clone().with_label(label.into());
        !self.asset_server.get_handles_untyped(&path).is_empty()
    }

    /// "Finishes" this context by populating the final [`Asset`] value (and the erased [`AssetMeta`] value, if it exists).
    /// The relevant asset metadata collected in this context will be stored in the returned [`LoadedAsset`].
    pub fn finish<A: Asset>(self, value: A, meta: Option<Box<dyn AssetMetaDyn>>) -> LoadedAsset<A> {
        LoadedAsset {
            value,
            dependencies: self.dependencies,
            loader_dependencies: self.loader_dependencies,
            labeled_assets: self.labeled_assets,
            meta,
        }
    }

    /// Gets the source path for this load context.
    pub fn path(&self) -> &Path {
        self.asset_path.path()
    }

    /// Gets the source asset path for this load context.
    pub fn asset_path(&self) -> &AssetPath<'static> {
        &self.asset_path
    }

    /// Reads the asset at the given path and returns its bytes
    pub async fn read_asset_bytes<'b, 'c>(
        &'b mut self,
        path: impl Into<AssetPath<'c>>,
    ) -> Result<Vec<u8>, ReadAssetBytesError> {
        let path = path.into();
        let source = self.asset_server.get_source(path.source())?;
        let asset_reader = match self.asset_server.mode() {
            AssetServerMode::Unprocessed { .. } => source.reader(),
            AssetServerMode::Processed { .. } => source.processed_reader()?,
        };
        let mut reader = asset_reader.read(path.path()).await?;
        let hash = if self.populate_hashes {
            // NOTE: ensure meta is read while the asset bytes reader is still active to ensure transactionality
            // See `ProcessorGatedReader` for more info
            let meta_bytes = asset_reader.read_meta_bytes(path.path()).await?;
            let minimal: ProcessedInfoMinimal = ron::de::from_bytes(&meta_bytes)
                .map_err(DeserializeMetaError::DeserializeMinimal)?;
            let processed_info = minimal
                .processed_info
                .ok_or(ReadAssetBytesError::MissingAssetHash)?;
            processed_info.full_hash
        } else {
            Default::default()
        };
        let mut bytes = Vec::new();
        reader
            .read_to_end(&mut bytes)
            .await
            .map_err(|source| ReadAssetBytesError::Io {
                path: path.path().to_path_buf(),
                source,
            })?;
        self.loader_dependencies.insert(path.clone_owned(), hash);
        Ok(bytes)
    }

    /// Returns a handle to an asset of type `A` with the label `label`. This [`LoadContext`] must produce an asset of the
    /// given type and the given label or the dependencies of this asset will never be considered "fully loaded". However you
    /// can call this method before _or_ after adding the labeled asset.
    pub fn get_label_handle<'b, A: Asset>(
        &mut self,
        label: impl Into<CowArc<'b, str>>,
    ) -> Handle<A> {
        let path = self.asset_path.clone().with_label(label);
        let handle = self.asset_server.get_or_create_path_handle::<A>(path, None);
        self.dependencies.insert(handle.id().untyped());
        handle
    }

    pub(crate) async fn load_direct_internal(
        &mut self,
        path: AssetPath<'static>,
        meta: Box<dyn AssetMetaDyn>,
        loader: &dyn ErasedAssetLoader,
        reader: &mut Reader<'_>,
    ) -> Result<ErasedLoadedAsset, LoadDirectError> {
        let loaded_asset = self
            .asset_server
            .load_with_meta_loader_and_reader(
                &path,
                meta,
                loader,
                reader,
                false,
                self.populate_hashes,
            )
            .await
            .map_err(|error| LoadDirectError {
                dependency: path.clone(),
                error,
            })?;
        let info = loaded_asset
            .meta
            .as_ref()
            .and_then(|m| m.processed_info().as_ref());
        let hash = info.map(|i| i.full_hash).unwrap_or(Default::default());
        self.loader_dependencies.insert(path, hash);
        Ok(loaded_asset)
    }

    /// Create a builder for loading nested assets in this context.
    #[must_use]
    pub fn loader(&mut self) -> NestedLoader<'a, '_> {
        NestedLoader::new(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.
    ///
    /// If you need to override asset settings, asset type, or load directly, please see [`LoadContext::loader`].
    pub fn load<'b, A: Asset>(&mut self, path: impl Into<AssetPath<'b>>) -> Handle<A> {
        self.loader().load(path)
    }
}

/// An error produced when calling [`LoadContext::read_asset_bytes`]
#[derive(Error, Debug)]
pub enum ReadAssetBytesError {
    #[error(transparent)]
    DeserializeMetaError(#[from] DeserializeMetaError),
    #[error(transparent)]
    AssetReaderError(#[from] AssetReaderError),
    #[error(transparent)]
    MissingAssetSourceError(#[from] MissingAssetSourceError),
    #[error(transparent)]
    MissingProcessedAssetReaderError(#[from] MissingProcessedAssetReaderError),
    /// Encountered an I/O error while loading an asset.
    #[error("Encountered an io error while loading asset at `{path}`: {source}")]
    Io {
        path: PathBuf,
        #[source]
        source: std::io::Error,
    },
    #[error("The LoadContext for this read_asset_bytes call requires hash metadata, but it was not provided. This is likely an internal implementation error.")]
    MissingAssetHash,
}