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
use crate::{
array_debug, enum_debug, list_debug, map_debug, serde::Serializable, struct_debug, tuple_debug,
tuple_struct_debug, Array, Enum, List, Map, Struct, Tuple, TupleStruct, TypeInfo, Typed,
ValueInfo,
};
use std::{
any::{self, Any, TypeId},
fmt::Debug,
};
use crate::utility::NonGenericTypeInfoCell;
pub use bevy_utils::AHasher as ReflectHasher;
/// An immutable enumeration of "kinds" of reflected type.
///
/// Each variant contains a trait object with methods specific to a kind of
/// type.
///
/// A `ReflectRef` is obtained via [`Reflect::reflect_ref`].
pub enum ReflectRef<'a> {
Struct(&'a dyn Struct),
TupleStruct(&'a dyn TupleStruct),
Tuple(&'a dyn Tuple),
List(&'a dyn List),
Array(&'a dyn Array),
Map(&'a dyn Map),
Enum(&'a dyn Enum),
Value(&'a dyn Reflect),
}
/// A mutable enumeration of "kinds" of reflected type.
///
/// Each variant contains a trait object with methods specific to a kind of
/// type.
///
/// A `ReflectMut` is obtained via [`Reflect::reflect_mut`].
pub enum ReflectMut<'a> {
Struct(&'a mut dyn Struct),
TupleStruct(&'a mut dyn TupleStruct),
Tuple(&'a mut dyn Tuple),
List(&'a mut dyn List),
Array(&'a mut dyn Array),
Map(&'a mut dyn Map),
Enum(&'a mut dyn Enum),
Value(&'a mut dyn Reflect),
}
/// An owned enumeration of "kinds" of reflected type.
///
/// Each variant contains a trait object with methods specific to a kind of
/// type.
///
/// A `ReflectOwned` is obtained via [`Reflect::reflect_owned`].
pub enum ReflectOwned {
Struct(Box<dyn Struct>),
TupleStruct(Box<dyn TupleStruct>),
Tuple(Box<dyn Tuple>),
List(Box<dyn List>),
Array(Box<dyn Array>),
Map(Box<dyn Map>),
Enum(Box<dyn Enum>),
Value(Box<dyn Reflect>),
}
/// A reflected Rust type.
///
/// Methods for working with particular kinds of Rust type are available using the [`Array`], [`List`],
/// [`Map`], [`Tuple`], [`TupleStruct`], [`Struct`], and [`Enum`] subtraits.
///
/// When using `#[derive(Reflect)]` on a struct, tuple struct or enum, the suitable subtrait for that
/// type (`Struct`, `TupleStruct` or `Enum`) is derived automatically.
pub trait Reflect: Any + Send + Sync {
/// Returns the [type name][std::any::type_name] of the underlying type.
fn type_name(&self) -> &str;
/// Returns the [`TypeInfo`] of the underlying type.
///
/// This method is great if you have an instance of a type or a `dyn Reflect`,
/// and want to access its [`TypeInfo`]. However, if this method is to be called
/// frequently, consider using [`TypeRegistry::get_type_info`] as it can be more
/// performant for such use cases.
///
/// [`TypeRegistry::get_type_info`]: crate::TypeRegistry::get_type_info
fn get_type_info(&self) -> &'static TypeInfo;
/// Returns the value as a [`Box<dyn Any>`][std::any::Any].
fn into_any(self: Box<Self>) -> Box<dyn Any>;
/// Returns the value as a [`&dyn Any`][std::any::Any].
fn as_any(&self) -> &dyn Any;
/// Returns the value as a [`&mut dyn Any`][std::any::Any].
fn as_any_mut(&mut self) -> &mut dyn Any;
/// Casts this type to a boxed reflected value.
fn into_reflect(self: Box<Self>) -> Box<dyn Reflect>;
/// Casts this type to a reflected value.
fn as_reflect(&self) -> &dyn Reflect;
/// Casts this type to a mutable reflected value.
fn as_reflect_mut(&mut self) -> &mut dyn Reflect;
/// Applies a reflected value to this value.
///
/// If a type implements a subtrait of `Reflect`, then the semantics of this
/// method are as follows:
/// - If `T` is a [`Struct`], then the value of each named field of `value` is
/// applied to the corresponding named field of `self`. Fields which are
/// not present in both structs are ignored.
/// - If `T` is a [`TupleStruct`] or [`Tuple`], then the value of each
/// numbered field is applied to the corresponding numbered field of
/// `self.` Fields which are not present in both values are ignored.
/// - If `T` is an [`Enum`], then the variant of `self` is `updated` to match
/// the variant of `value`. The corresponding fields of that variant are
/// applied from `value` onto `self`. Fields which are not present in both
/// values are ignored.
/// - If `T` is a [`List`] or [`Array`], then each element of `value` is applied
/// to the corresponding element of `self`. Up to `self.len()` items are applied,
/// and excess elements in `value` are appended to `self`.
/// - If `T` is a [`Map`], then for each key in `value`, the associated
/// value is applied to the value associated with the same key in `self`.
/// Keys which are not present in `self` are inserted.
/// - If `T` is none of these, then `value` is downcast to `T`, cloned, and
/// assigned to `self`.
///
/// Note that `Reflect` must be implemented manually for [`List`]s and
/// [`Map`]s in order to achieve the correct semantics, as derived
/// implementations will have the semantics for [`Struct`], [`TupleStruct`], [`Enum`]
/// or none of the above depending on the kind of type. For lists and maps, use the
/// [`list_apply`] and [`map_apply`] helper functions when implementing this method.
///
/// [`list_apply`]: crate::list_apply
/// [`map_apply`]: crate::map_apply
///
/// # Panics
///
/// Derived implementations of this method will panic:
/// - If the type of `value` is not of the same kind as `T` (e.g. if `T` is
/// a `List`, while `value` is a `Struct`).
/// - If `T` is any complex type and the corresponding fields or elements of
/// `self` and `value` are not of the same type.
/// - If `T` is a value type and `self` cannot be downcast to `T`
fn apply(&mut self, value: &dyn Reflect);
/// Performs a type-checked assignment of a reflected value to this value.
///
/// If `value` does not contain a value of type `T`, returns an `Err`
/// containing the trait object.
fn set(&mut self, value: Box<dyn Reflect>) -> Result<(), Box<dyn Reflect>>;
/// Returns an enumeration of "kinds" of type.
///
/// See [`ReflectRef`].
fn reflect_ref(&self) -> ReflectRef;
/// Returns a mutable enumeration of "kinds" of type.
///
/// See [`ReflectMut`].
fn reflect_mut(&mut self) -> ReflectMut;
/// Returns an owned enumeration of "kinds" of type.
///
/// See [`ReflectOwned`].
fn reflect_owned(self: Box<Self>) -> ReflectOwned;
/// Clones the value as a `Reflect` trait object.
///
/// When deriving `Reflect` for a struct, tuple struct or enum, the value is
/// cloned via [`Struct::clone_dynamic`], [`TupleStruct::clone_dynamic`],
/// or [`Enum::clone_dynamic`], respectively.
/// Implementors of other `Reflect` subtraits (e.g. [`List`], [`Map`]) should
/// use those subtraits' respective `clone_dynamic` methods.
fn clone_value(&self) -> Box<dyn Reflect>;
/// Returns a hash of the value (which includes the type).
///
/// If the underlying type does not support hashing, returns `None`.
fn reflect_hash(&self) -> Option<u64> {
None
}
/// Returns a "partial equality" comparison result.
///
/// If the underlying type does not support equality testing, returns `None`.
fn reflect_partial_eq(&self, _value: &dyn Reflect) -> Option<bool> {
None
}
/// Debug formatter for the value.
///
/// Any value that is not an implementor of other `Reflect` subtraits
/// (e.g. [`List`], [`Map`]), will default to the format: `"Reflect(type_name)"`,
/// where `type_name` is the [type name] of the underlying type.
///
/// [type name]: Self::type_name
fn debug(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
match self.reflect_ref() {
ReflectRef::Struct(dyn_struct) => struct_debug(dyn_struct, f),
ReflectRef::TupleStruct(dyn_tuple_struct) => tuple_struct_debug(dyn_tuple_struct, f),
ReflectRef::Tuple(dyn_tuple) => tuple_debug(dyn_tuple, f),
ReflectRef::List(dyn_list) => list_debug(dyn_list, f),
ReflectRef::Array(dyn_array) => array_debug(dyn_array, f),
ReflectRef::Map(dyn_map) => map_debug(dyn_map, f),
ReflectRef::Enum(dyn_enum) => enum_debug(dyn_enum, f),
_ => write!(f, "Reflect({})", self.type_name()),
}
}
/// Returns a serializable version of the value.
///
/// If the underlying type does not support serialization, returns `None`.
fn serializable(&self) -> Option<Serializable> {
None
}
}
/// A trait for types which can be constructed from a reflected type.
///
/// This trait can be derived on types which implement [`Reflect`]. Some complex
/// types (such as `Vec<T>`) may only be reflected if their element types
/// implement this trait.
///
/// For structs and tuple structs, fields marked with the `#[reflect(ignore)]`
/// attribute will be constructed using the `Default` implementation of the
/// field type, rather than the corresponding field value (if any) of the
/// reflected value.
pub trait FromReflect: Reflect + Sized {
/// Constructs a concrete instance of `Self` from a reflected value.
fn from_reflect(reflect: &dyn Reflect) -> Option<Self>;
}
impl Debug for dyn Reflect {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
self.debug(f)
}
}
impl Typed for dyn Reflect {
fn type_info() -> &'static TypeInfo {
static CELL: NonGenericTypeInfoCell = NonGenericTypeInfoCell::new();
CELL.get_or_set(|| TypeInfo::Value(ValueInfo::new::<Self>()))
}
}
#[deny(rustdoc::broken_intra_doc_links)]
impl dyn Reflect {
/// Downcasts the value to type `T`, consuming the trait object.
///
/// If the underlying value is not of type `T`, returns `Err(self)`.
pub fn downcast<T: Reflect>(self: Box<dyn Reflect>) -> Result<Box<T>, Box<dyn Reflect>> {
if self.is::<T>() {
Ok(self.into_any().downcast().unwrap())
} else {
Err(self)
}
}
/// Downcasts the value to type `T`, unboxing and consuming the trait object.
///
/// If the underlying value is not of type `T`, returns `Err(self)`.
pub fn take<T: Reflect>(self: Box<dyn Reflect>) -> Result<T, Box<dyn Reflect>> {
self.downcast::<T>().map(|value| *value)
}
/// Returns `true` if the underlying value represents a value of type `T`, or `false`
/// otherwise.
///
/// Read `is` for more information on underlying values and represented types.
#[inline]
pub fn represents<T: Reflect>(&self) -> bool {
self.type_name() == any::type_name::<T>()
}
/// Returns `true` if the underlying value is of type `T`, or `false`
/// otherwise.
///
/// The underlying value is the concrete type that is stored in this `dyn` object;
/// it can be downcasted to. In the case that this underlying value "represents"
/// a different type, like the Dynamic\*\*\* types do, you can call `represents`
/// to determine what type they represent. Represented types cannot be downcasted
/// to, but you can use [`FromReflect`] to create a value of the represented type from them.
#[inline]
pub fn is<T: Reflect>(&self) -> bool {
self.type_id() == TypeId::of::<T>()
}
/// Downcasts the value to type `T` by reference.
///
/// If the underlying value is not of type `T`, returns `None`.
#[inline]
pub fn downcast_ref<T: Reflect>(&self) -> Option<&T> {
self.as_any().downcast_ref::<T>()
}
/// Downcasts the value to type `T` by mutable reference.
///
/// If the underlying value is not of type `T`, returns `None`.
#[inline]
pub fn downcast_mut<T: Reflect>(&mut self) -> Option<&mut T> {
self.as_any_mut().downcast_mut::<T>()
}
}