bevy_reflect/reflect.rs
1use crate::{
2 array::array_debug, enums::enum_debug, list::list_debug, map::map_debug, set::set_debug,
3 structs::struct_debug, tuple::tuple_debug, tuple_struct::tuple_struct_debug, DynamicTypePath,
4 DynamicTyped, OpaqueInfo, ReflectCloneError, ReflectKind, ReflectKindMismatchError, ReflectMut,
5 ReflectOwned, ReflectRef, TypeInfo, TypePath, Typed,
6};
7use alloc::borrow::Cow;
8use alloc::boxed::Box;
9use alloc::string::ToString;
10use core::{
11 any::{Any, TypeId},
12 cmp::Ordering,
13 fmt::Debug,
14};
15
16use thiserror::Error;
17
18use crate::utility::NonGenericTypeInfoCell;
19
20/// A enumeration of all error outcomes that might happen when running [`try_apply`](PartialReflect::try_apply).
21#[derive(Error, Debug)]
22pub enum ApplyError {
23 #[error("attempted to apply `{from_kind}` to `{to_kind}`")]
24 /// Attempted to apply the wrong [kind](ReflectKind) to a type, e.g. a struct to an enum.
25 MismatchedKinds {
26 /// Kind of the value we attempted to apply.
27 from_kind: ReflectKind,
28 /// Kind of the type we attempted to apply the value to.
29 to_kind: ReflectKind,
30 },
31
32 #[error("enum variant `{variant_name}` doesn't have a field named `{field_name}`")]
33 /// Enum variant that we tried to apply to was missing a field.
34 MissingEnumField {
35 /// Name of the enum variant.
36 variant_name: Box<str>,
37 /// Name of the missing field.
38 field_name: Box<str>,
39 },
40
41 #[error("`{from_type}` is not `{to_type}`")]
42 /// Tried to apply incompatible types.
43 MismatchedTypes {
44 /// Type of the value we attempted to apply.
45 from_type: Box<str>,
46 /// Type we attempted to apply the value to.
47 to_type: Box<str>,
48 },
49
50 #[error("attempted to apply type with {from_size} size to a type with {to_size} size")]
51 /// Attempted to apply an [array-like] type to another of different size, e.g. a [u8; 4] to [u8; 3].
52 ///
53 /// [array-like]: crate::array::Array
54 DifferentSize {
55 /// Size of the value we attempted to apply, in elements.
56 from_size: usize,
57 /// Size of the type we attempted to apply the value to, in elements.
58 to_size: usize,
59 },
60
61 #[error("variant with name `{variant_name}` does not exist on enum `{enum_name}`")]
62 /// The enum we tried to apply to didn't contain a variant with the give name.
63 UnknownVariant {
64 /// Name of the enum.
65 enum_name: Box<str>,
66 /// Name of the missing variant.
67 variant_name: Box<str>,
68 },
69}
70
71impl From<ReflectKindMismatchError> for ApplyError {
72 fn from(value: ReflectKindMismatchError) -> Self {
73 Self::MismatchedKinds {
74 from_kind: value.received,
75 to_kind: value.expected,
76 }
77 }
78}
79
80/// The foundational trait of [`bevy_reflect`], used for accessing and modifying data dynamically.
81///
82/// This is a supertrait of [`Reflect`],
83/// meaning any type which implements `Reflect` implements `PartialReflect` by definition.
84///
85/// It's recommended to use [the derive macro for `Reflect`] rather than manually implementing this trait.
86/// Doing so will automatically implement this trait as well as many other useful traits for reflection,
87/// including one of the appropriate subtraits: [`Struct`], [`TupleStruct`] or [`Enum`].
88///
89/// See the [crate-level documentation] to see how this trait and its subtraits can be used.
90///
91/// [`bevy_reflect`]: crate
92/// [the derive macro for `Reflect`]: bevy_reflect_derive::Reflect
93/// [`Struct`]: crate::structs::Struct
94/// [`TupleStruct`]: crate::tuple_struct::TupleStruct
95/// [`Enum`]: crate::enums::Enum
96/// [crate-level documentation]: crate
97#[diagnostic::on_unimplemented(
98 message = "`{Self}` does not implement `PartialReflect` so cannot be introspected",
99 note = "consider annotating `{Self}` with `#[derive(Reflect)]`"
100)]
101pub trait PartialReflect: DynamicTypePath + Send + Sync
102where
103 // NB: we don't use `Self: Any` since for downcasting, `Reflect` should be used.
104 Self: 'static,
105{
106 /// Returns the [`TypeInfo`] of the type _represented_ by this value.
107 ///
108 /// For most types, this will simply return their own `TypeInfo`.
109 /// However, for dynamic types, such as [`DynamicStruct`] or [`DynamicList`],
110 /// this will return the type they represent
111 /// (or `None` if they don't represent any particular type).
112 ///
113 /// This method is great if you have an instance of a type or a `dyn Reflect`,
114 /// and want to access its [`TypeInfo`]. However, if this method is to be called
115 /// frequently, consider using [`TypeRegistry::get_type_info`] as it can be more
116 /// performant for such use cases.
117 ///
118 /// [`DynamicStruct`]: crate::structs::DynamicStruct
119 /// [`DynamicList`]: crate::list::DynamicList
120 /// [`TypeRegistry::get_type_info`]: crate::TypeRegistry::get_type_info
121 fn get_represented_type_info(&self) -> Option<&'static TypeInfo>;
122
123 /// Casts this type to a boxed, reflected value.
124 ///
125 /// This is useful for coercing trait objects.
126 fn into_partial_reflect(self: Box<Self>) -> Box<dyn PartialReflect>;
127
128 /// Casts this type to a reflected value.
129 ///
130 /// This is useful for coercing trait objects.
131 fn as_partial_reflect(&self) -> &dyn PartialReflect;
132
133 /// Casts this type to a mutable, reflected value.
134 ///
135 /// This is useful for coercing trait objects.
136 fn as_partial_reflect_mut(&mut self) -> &mut dyn PartialReflect;
137
138 /// Attempts to cast this type to a boxed, [fully-reflected] value.
139 ///
140 /// [fully-reflected]: Reflect
141 fn try_into_reflect(self: Box<Self>) -> Result<Box<dyn Reflect>, Box<dyn PartialReflect>>;
142
143 /// Attempts to cast this type to a [fully-reflected] value.
144 ///
145 /// [fully-reflected]: Reflect
146 fn try_as_reflect(&self) -> Option<&dyn Reflect>;
147
148 /// Attempts to cast this type to a mutable, [fully-reflected] value.
149 ///
150 /// [fully-reflected]: Reflect
151 fn try_as_reflect_mut(&mut self) -> Option<&mut dyn Reflect>;
152
153 /// Applies a reflected value to this value.
154 ///
155 /// If `Self` implements a [reflection subtrait], then the semantics of this
156 /// method are as follows:
157 /// - If `Self` is a [`Struct`], then the value of each named field of `value` is
158 /// applied to the corresponding named field of `self`. Fields which are
159 /// not present in both structs are ignored.
160 /// - If `Self` is a [`TupleStruct`] or [`Tuple`], then the value of each
161 /// numbered field is applied to the corresponding numbered field of
162 /// `self.` Fields which are not present in both values are ignored.
163 /// - If `Self` is an [`Enum`], then the variant of `self` is `updated` to match
164 /// the variant of `value`. The corresponding fields of that variant are
165 /// applied from `value` onto `self`. Fields which are not present in both
166 /// values are ignored.
167 /// - If `Self` is a [`List`] or [`Array`], then each element of `value` is applied
168 /// to the corresponding element of `self`. Up to `self.len()` items are applied,
169 /// and excess elements in `value` are appended to `self`.
170 /// - If `Self` is a [`Map`], then for each key in `value`, the associated
171 /// value is applied to the value associated with the same key in `self`.
172 /// Keys which are not present in `self` are inserted, and keys from `self` which are not present in `value` are removed.
173 /// - If `Self` is a [`Set`], then each element of `value` is applied to the corresponding
174 /// element of `Self`. If an element of `value` does not exist in `Self` then it is
175 /// cloned and inserted. If an element from `self` is not present in `value` then it is removed.
176 /// - If `Self` is none of these, then `value` is downcast to `Self`, cloned, and
177 /// assigned to `self`.
178 ///
179 /// Note that `Reflect` must be implemented manually for [`List`]s,
180 /// [`Map`]s, and [`Set`]s in order to achieve the correct semantics, as derived
181 /// implementations will have the semantics for [`Struct`], [`TupleStruct`], [`Enum`]
182 /// or none of the above depending on the kind of type. For lists, maps, and sets, use the
183 /// [`list_apply`], [`map_apply`], and [`set_apply`] helper functions when implementing this method.
184 ///
185 /// [reflection subtrait]: crate#the-reflection-subtraits
186 /// [`Struct`]: crate::structs::Struct
187 /// [`TupleStruct`]: crate::tuple_struct::TupleStruct
188 /// [`Tuple`]: crate::tuple::Tuple
189 /// [`Enum`]: crate::enums::Enum
190 /// [`List`]: crate::list::List
191 /// [`Array`]: crate::array::Array
192 /// [`Map`]: crate::map::Map
193 /// [`Set`]: crate::set::Set
194 /// [`list_apply`]: crate::list::list_apply
195 /// [`map_apply`]: crate::map::map_apply
196 /// [`set_apply`]: crate::set::set_apply
197 ///
198 /// # Panics
199 ///
200 /// Derived implementations of this method will panic:
201 /// - If the type of `value` is not of the same kind as `Self` (e.g. if `Self` is
202 /// a `List`, while `value` is a `Struct`).
203 /// - If `Self` is any complex type and the corresponding fields or elements of
204 /// `self` and `value` are not of the same type.
205 /// - If `Self` is an opaque type and `value` cannot be downcast to `Self`
206 fn apply(&mut self, value: &dyn PartialReflect) {
207 PartialReflect::try_apply(self, value).unwrap();
208 }
209
210 /// Tries to [`apply`](PartialReflect::apply) a reflected value to this value.
211 ///
212 /// Functions the same as the [`apply`](PartialReflect::apply) function but returns an error instead of
213 /// panicking.
214 ///
215 /// # Handling Errors
216 ///
217 /// This function may leave `self` in a partially mutated state if a error was encountered on the way.
218 /// consider maintaining a cloned instance of this data you can switch to if a error is encountered.
219 fn try_apply(&mut self, value: &dyn PartialReflect) -> Result<(), ApplyError>;
220
221 /// Returns a zero-sized enumeration of "kinds" of type.
222 ///
223 /// See [`ReflectKind`].
224 fn reflect_kind(&self) -> ReflectKind {
225 self.reflect_ref().kind()
226 }
227
228 /// Returns an immutable enumeration of "kinds" of type.
229 ///
230 /// See [`ReflectRef`].
231 fn reflect_ref(&self) -> ReflectRef<'_>;
232
233 /// Returns a mutable enumeration of "kinds" of type.
234 ///
235 /// See [`ReflectMut`].
236 fn reflect_mut(&mut self) -> ReflectMut<'_>;
237
238 /// Returns an owned enumeration of "kinds" of type.
239 ///
240 /// See [`ReflectOwned`].
241 fn reflect_owned(self: Box<Self>) -> ReflectOwned;
242
243 /// Converts this reflected value into its dynamic representation based on its [kind].
244 ///
245 /// For example, a [`List`] type will internally invoke [`List::to_dynamic_list`], returning [`DynamicList`].
246 /// A [`Struct`] type will invoke [`Struct::to_dynamic_struct`], returning [`DynamicStruct`].
247 /// And so on.
248 ///
249 /// If the [kind] is [opaque], then the value will attempt to be cloned directly via [`reflect_clone`],
250 /// since opaque types do not have any standard dynamic representation.
251 ///
252 /// To attempt to clone the value directly such that it returns a concrete instance of this type,
253 /// use [`reflect_clone`].
254 ///
255 /// # Panics
256 ///
257 /// This method will panic if the [kind] is [opaque] and the call to [`reflect_clone`] fails.
258 ///
259 /// # Example
260 ///
261 /// ```
262 /// # use bevy_reflect::{PartialReflect};
263 /// let value = (1, true, 3.14);
264 /// let dynamic_value = value.to_dynamic();
265 /// assert!(dynamic_value.is_dynamic())
266 /// ```
267 ///
268 /// [kind]: PartialReflect::reflect_kind
269 /// [`List`]: crate::list::List
270 /// [`List::to_dynamic_list`]: crate::list::List::to_dynamic_list
271 /// [`DynamicList`]: crate::list::DynamicList
272 /// [`Struct`]: crate::structs::Struct
273 /// [`Struct::to_dynamic_struct`]: crate::structs::Struct::to_dynamic_struct
274 /// [`DynamicStruct`]: crate::structs::DynamicStruct
275 /// [opaque]: crate::ReflectKind::Opaque
276 /// [`reflect_clone`]: PartialReflect::reflect_clone
277 fn to_dynamic(&self) -> Box<dyn PartialReflect> {
278 match self.reflect_ref() {
279 ReflectRef::Struct(dyn_struct) => Box::new(dyn_struct.to_dynamic_struct()),
280 ReflectRef::TupleStruct(dyn_tuple_struct) => {
281 Box::new(dyn_tuple_struct.to_dynamic_tuple_struct())
282 }
283 ReflectRef::Tuple(dyn_tuple) => Box::new(dyn_tuple.to_dynamic_tuple()),
284 ReflectRef::List(dyn_list) => Box::new(dyn_list.to_dynamic_list()),
285 ReflectRef::Array(dyn_array) => Box::new(dyn_array.to_dynamic_array()),
286 ReflectRef::Map(dyn_map) => Box::new(dyn_map.to_dynamic_map()),
287 ReflectRef::Set(dyn_set) => Box::new(dyn_set.to_dynamic_set()),
288 ReflectRef::Enum(dyn_enum) => Box::new(dyn_enum.to_dynamic_enum()),
289 #[cfg(feature = "functions")]
290 ReflectRef::Function(dyn_function) => Box::new(dyn_function.to_dynamic_function()),
291 ReflectRef::Opaque(value) => value.reflect_clone().unwrap().into_partial_reflect(),
292 }
293 }
294
295 /// Attempts to clone `Self` using reflection.
296 ///
297 /// Unlike [`to_dynamic`], which generally returns a dynamic representation of `Self`,
298 /// this method attempts create a clone of `Self` directly, if possible.
299 ///
300 /// If the clone cannot be performed, an appropriate [`ReflectCloneError`] is returned.
301 ///
302 /// # Example
303 ///
304 /// ```
305 /// # use bevy_reflect::PartialReflect;
306 /// let value = (1, true, 3.14);
307 /// let cloned = value.reflect_clone().unwrap();
308 /// assert!(cloned.is::<(i32, bool, f64)>())
309 /// ```
310 ///
311 /// [`to_dynamic`]: PartialReflect::to_dynamic
312 fn reflect_clone(&self) -> Result<Box<dyn Reflect>, ReflectCloneError> {
313 Err(ReflectCloneError::NotImplemented {
314 type_path: Cow::Owned(self.reflect_type_path().to_string()),
315 })
316 }
317
318 /// For a type implementing [`PartialReflect`], combines `reflect_clone` and
319 /// `take` in a useful fashion, automatically constructing an appropriate
320 /// [`ReflectCloneError`] if the downcast fails.
321 fn reflect_clone_and_take<T: 'static>(&self) -> Result<T, ReflectCloneError>
322 where
323 Self: TypePath + Sized,
324 {
325 self.reflect_clone()?
326 .take()
327 .map_err(|_| ReflectCloneError::FailedDowncast {
328 expected: Cow::Borrowed(<Self as TypePath>::type_path()),
329 received: Cow::Owned(self.reflect_type_path().to_string()),
330 })
331 }
332
333 /// Returns a hash of the value (which includes the type).
334 ///
335 /// If the underlying type does not support hashing, returns `None`.
336 fn reflect_hash(&self) -> Option<u64> {
337 None
338 }
339
340 /// Returns a "partial equality" comparison result.
341 ///
342 /// If the underlying type does not support equality testing, returns `None`.
343 fn reflect_partial_eq(&self, _value: &dyn PartialReflect) -> Option<bool> {
344 None
345 }
346
347 /// Returns a "partial comparison" result.
348 ///
349 /// If the underlying type does not support it, returns `None`.
350 fn reflect_partial_cmp(&self, _value: &dyn PartialReflect) -> Option<Ordering> {
351 None
352 }
353
354 /// Debug formatter for the value.
355 ///
356 /// Any value that is not an implementor of other `Reflect` subtraits
357 /// (e.g. [`List`], [`Map`]), will default to the format: `"Reflect(type_path)"`,
358 /// where `type_path` is the [type path] of the underlying type.
359 ///
360 /// [`List`]: crate::list::List
361 /// [`Map`]: crate::map::Map
362 /// [type path]: TypePath::type_path
363 fn debug(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
364 match self.reflect_ref() {
365 ReflectRef::Struct(dyn_struct) => struct_debug(dyn_struct, f),
366 ReflectRef::TupleStruct(dyn_tuple_struct) => tuple_struct_debug(dyn_tuple_struct, f),
367 ReflectRef::Tuple(dyn_tuple) => tuple_debug(dyn_tuple, f),
368 ReflectRef::List(dyn_list) => list_debug(dyn_list, f),
369 ReflectRef::Array(dyn_array) => array_debug(dyn_array, f),
370 ReflectRef::Map(dyn_map) => map_debug(dyn_map, f),
371 ReflectRef::Set(dyn_set) => set_debug(dyn_set, f),
372 ReflectRef::Enum(dyn_enum) => enum_debug(dyn_enum, f),
373 #[cfg(feature = "functions")]
374 ReflectRef::Function(dyn_function) => dyn_function.fmt(f),
375 ReflectRef::Opaque(_) => write!(f, "Reflect({})", self.reflect_type_path()),
376 }
377 }
378
379 /// Indicates whether or not this type is a _dynamic_ type.
380 ///
381 /// Dynamic types include the ones built-in to this [crate],
382 /// such as [`DynamicStruct`], [`DynamicList`], and [`DynamicTuple`].
383 /// However, they may be custom types used as proxies for other types
384 /// or to facilitate scripting capabilities.
385 ///
386 /// By default, this method will return `false`.
387 ///
388 /// [`DynamicStruct`]: crate::structs::DynamicStruct
389 /// [`DynamicList`]: crate::list::DynamicList
390 /// [`DynamicTuple`]: crate::tuple::DynamicTuple
391 fn is_dynamic(&self) -> bool {
392 false
393 }
394}
395
396/// A core trait of [`bevy_reflect`], used for downcasting to concrete types.
397///
398/// This is a subtrait of [`PartialReflect`],
399/// meaning any type which implements `Reflect` implements `PartialReflect` by definition.
400///
401/// It's recommended to use [the derive macro] rather than manually implementing this trait.
402/// Doing so will automatically implement this trait, [`PartialReflect`], and many other useful traits for reflection,
403/// including one of the appropriate subtraits: [`Struct`], [`TupleStruct`] or [`Enum`].
404///
405/// If you need to use this trait as a generic bound along with other reflection traits,
406/// for your convenience, consider using [`Reflectable`] instead.
407///
408/// See the [crate-level documentation] to see how this trait can be used.
409///
410/// [`bevy_reflect`]: crate
411/// [the derive macro]: bevy_reflect_derive::Reflect
412/// [`Struct`]: crate::structs::Struct
413/// [`TupleStruct`]: crate::tuple_struct::TupleStruct
414/// [`Enum`]: crate::enums::Enum
415/// [`Reflectable`]: crate::Reflectable
416/// [crate-level documentation]: crate
417#[diagnostic::on_unimplemented(
418 message = "`{Self}` does not implement `Reflect` so cannot be fully reflected",
419 note = "consider annotating `{Self}` with `#[derive(Reflect)]`"
420)]
421pub trait Reflect: PartialReflect + DynamicTyped + Any {
422 /// Returns the value as a [`Box<dyn Any>`][core::any::Any].
423 ///
424 /// For remote wrapper types, this will return the remote type instead.
425 fn into_any(self: Box<Self>) -> Box<dyn Any>;
426
427 /// Returns the value as a [`&dyn Any`][core::any::Any].
428 ///
429 /// For remote wrapper types, this will return the remote type instead.
430 fn as_any(&self) -> &dyn Any;
431
432 /// Returns the value as a [`&mut dyn Any`][core::any::Any].
433 ///
434 /// For remote wrapper types, this will return the remote type instead.
435 fn as_any_mut(&mut self) -> &mut dyn Any;
436
437 /// Casts this type to a boxed, fully-reflected value.
438 fn into_reflect(self: Box<Self>) -> Box<dyn Reflect>;
439
440 /// Casts this type to a fully-reflected value.
441 fn as_reflect(&self) -> &dyn Reflect;
442
443 /// Casts this type to a mutable, fully-reflected value.
444 fn as_reflect_mut(&mut self) -> &mut dyn Reflect;
445
446 /// Performs a type-checked assignment of a reflected value to this value.
447 ///
448 /// If `value` does not contain a value of type `T`, returns an `Err`
449 /// containing the trait object.
450 fn set(&mut self, value: Box<dyn Reflect>) -> Result<(), Box<dyn Reflect>>;
451}
452
453impl dyn PartialReflect {
454 /// Returns `true` if the underlying value represents a value of type `T`, or `false`
455 /// otherwise.
456 ///
457 /// Read `is` for more information on underlying values and represented types.
458 #[inline]
459 pub fn represents<T: Reflect + TypePath>(&self) -> bool {
460 self.get_represented_type_info()
461 .is_some_and(|t| t.type_path() == T::type_path())
462 }
463
464 /// Downcasts the value to type `T`, consuming the trait object.
465 ///
466 /// If the underlying value does not implement [`Reflect`]
467 /// or is not of type `T`, returns `Err(self)`.
468 ///
469 /// For remote types, `T` should be the type itself rather than the wrapper type.
470 pub fn try_downcast<T: Any>(
471 self: Box<dyn PartialReflect>,
472 ) -> Result<Box<T>, Box<dyn PartialReflect>> {
473 self.try_into_reflect()?
474 .downcast()
475 .map_err(PartialReflect::into_partial_reflect)
476 }
477
478 /// Downcasts the value to type `T`, unboxing and consuming the trait object.
479 ///
480 /// If the underlying value does not implement [`Reflect`]
481 /// or is not of type `T`, returns `Err(self)`.
482 ///
483 /// For remote types, `T` should be the type itself rather than the wrapper type.
484 pub fn try_take<T: Any>(self: Box<dyn PartialReflect>) -> Result<T, Box<dyn PartialReflect>> {
485 self.try_downcast().map(|value| *value)
486 }
487
488 /// Downcasts the value to type `T` by reference.
489 ///
490 /// If the underlying value does not implement [`Reflect`]
491 /// or is not of type `T`, returns [`None`].
492 ///
493 /// For remote types, `T` should be the type itself rather than the wrapper type.
494 pub fn try_downcast_ref<T: Any>(&self) -> Option<&T> {
495 self.try_as_reflect()?.downcast_ref()
496 }
497
498 /// Downcasts the value to type `T` by mutable reference.
499 ///
500 /// If the underlying value does not implement [`Reflect`]
501 /// or is not of type `T`, returns [`None`].
502 ///
503 /// For remote types, `T` should be the type itself rather than the wrapper type.
504 pub fn try_downcast_mut<T: Any>(&mut self) -> Option<&mut T> {
505 self.try_as_reflect_mut()?.downcast_mut()
506 }
507}
508
509impl Debug for dyn PartialReflect {
510 fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
511 self.debug(f)
512 }
513}
514
515// The following implementation never actually shadows the concrete TypePath implementation.
516// See the comment on `dyn Reflect`'s `TypePath` implementation.
517impl TypePath for dyn PartialReflect {
518 fn type_path() -> &'static str {
519 "dyn bevy_reflect::PartialReflect"
520 }
521
522 fn short_type_path() -> &'static str {
523 "dyn PartialReflect"
524 }
525}
526
527#[deny(rustdoc::broken_intra_doc_links)]
528impl dyn Reflect {
529 /// Downcasts the value to type `T`, consuming the trait object.
530 ///
531 /// If the underlying value is not of type `T`, returns `Err(self)`.
532 ///
533 /// For remote types, `T` should be the type itself rather than the wrapper type.
534 pub fn downcast<T: Any>(self: Box<dyn Reflect>) -> Result<Box<T>, Box<dyn Reflect>> {
535 if self.is::<T>() {
536 Ok(self.into_any().downcast().unwrap())
537 } else {
538 Err(self)
539 }
540 }
541
542 /// Downcasts the value to type `T`, unboxing and consuming the trait object.
543 ///
544 /// If the underlying value is not of type `T`, returns `Err(self)`.
545 ///
546 /// For remote types, `T` should be the type itself rather than the wrapper type.
547 pub fn take<T: Any>(self: Box<dyn Reflect>) -> Result<T, Box<dyn Reflect>> {
548 self.downcast::<T>().map(|value| *value)
549 }
550
551 /// Returns `true` if the underlying value is of type `T`, or `false`
552 /// otherwise.
553 ///
554 /// The underlying value is the concrete type that is stored in this `dyn` object;
555 /// it can be downcast to. In the case that this underlying value "represents"
556 /// a different type, like the Dynamic\*\*\* types do, you can call `represents`
557 /// to determine what type they represent. Represented types cannot be downcast
558 /// to, but you can use [`FromReflect`] to create a value of the represented type from them.
559 ///
560 /// For remote types, `T` should be the type itself rather than the wrapper type.
561 ///
562 /// [`FromReflect`]: crate::FromReflect
563 #[inline]
564 pub fn is<T: Any>(&self) -> bool {
565 self.as_any().type_id() == TypeId::of::<T>()
566 }
567
568 /// Downcasts the value to type `T` by reference.
569 ///
570 /// If the underlying value is not of type `T`, returns `None`.
571 ///
572 /// For remote types, `T` should be the type itself rather than the wrapper type.
573 #[inline]
574 pub fn downcast_ref<T: Any>(&self) -> Option<&T> {
575 self.as_any().downcast_ref::<T>()
576 }
577
578 /// Downcasts the value to type `T` by mutable reference.
579 ///
580 /// If the underlying value is not of type `T`, returns `None`.
581 ///
582 /// For remote types, `T` should be the type itself rather than the wrapper type.
583 #[inline]
584 pub fn downcast_mut<T: Any>(&mut self) -> Option<&mut T> {
585 self.as_any_mut().downcast_mut::<T>()
586 }
587}
588
589impl Debug for dyn Reflect {
590 fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
591 self.debug(f)
592 }
593}
594
595impl Typed for dyn Reflect {
596 fn type_info() -> &'static TypeInfo {
597 static CELL: NonGenericTypeInfoCell = NonGenericTypeInfoCell::new();
598 CELL.get_or_set(|| TypeInfo::Opaque(OpaqueInfo::new::<Self>()))
599 }
600}
601
602// The following implementation never actually shadows the concrete `TypePath` implementation.
603// See this playground (https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=589064053f27bc100d90da89c6a860aa).
604impl TypePath for dyn Reflect {
605 fn type_path() -> &'static str {
606 "dyn bevy_reflect::Reflect"
607 }
608
609 fn short_type_path() -> &'static str {
610 "dyn Reflect"
611 }
612}
613
614macro_rules! impl_full_reflect {
615 ($(<$($id:ident),* $(,)?>)? for $ty:ty $(where $($tt:tt)*)?) => {
616 impl $(<$($id),*>)? $crate::Reflect for $ty $(where $($tt)*)? {
617 fn into_any(self: bevy_platform::prelude::Box<Self>) -> bevy_platform::prelude::Box<dyn ::core::any::Any> {
618 self
619 }
620
621 fn as_any(&self) -> &dyn ::core::any::Any {
622 self
623 }
624
625 fn as_any_mut(&mut self) -> &mut dyn ::core::any::Any {
626 self
627 }
628
629 fn into_reflect(self: bevy_platform::prelude::Box<Self>) -> bevy_platform::prelude::Box<dyn $crate::Reflect> {
630 self
631 }
632
633 fn as_reflect(&self) -> &dyn $crate::Reflect {
634 self
635 }
636
637 fn as_reflect_mut(&mut self) -> &mut dyn $crate::Reflect {
638 self
639 }
640
641 fn set(
642 &mut self,
643 value: bevy_platform::prelude::Box<dyn $crate::Reflect>,
644 ) -> Result<(), bevy_platform::prelude::Box<dyn $crate::Reflect>> {
645 *self = <dyn $crate::Reflect>::take(value)?;
646 Ok(())
647 }
648 }
649 };
650}
651
652pub(crate) use impl_full_reflect;