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//! Definitions for [`Bundle`] reflection.
//! This allows inserting, updating and/or removing bundles whose type is only known at runtime.
//!
//! This module exports two types: [`ReflectBundleFns`] and [`ReflectBundle`].
//!
//! Same as [`super::component`], but for bundles.
use std::any::TypeId;
use crate::{
prelude::Bundle,
world::{EntityMut, EntityWorldMut},
};
use bevy_reflect::{FromReflect, FromType, Reflect, ReflectRef, TypeRegistry};
use super::{from_reflect_with_fallback, ReflectComponent};
/// A struct used to operate on reflected [`Bundle`] trait of a type.
///
/// A [`ReflectBundle`] for type `T` can be obtained via
/// [`bevy_reflect::TypeRegistration::data`].
#[derive(Clone)]
pub struct ReflectBundle(ReflectBundleFns);
/// The raw function pointers needed to make up a [`ReflectBundle`].
///
/// The also [`super::component::ReflectComponentFns`].
#[derive(Clone)]
pub struct ReflectBundleFns {
/// Function pointer implementing [`ReflectBundle::insert()`].
pub insert: fn(&mut EntityWorldMut, &dyn Reflect, &TypeRegistry),
/// Function pointer implementing [`ReflectBundle::apply()`].
pub apply: fn(EntityMut, &dyn Reflect, &TypeRegistry),
/// Function pointer implementing [`ReflectBundle::apply_or_insert()`].
pub apply_or_insert: fn(&mut EntityWorldMut, &dyn Reflect, &TypeRegistry),
/// Function pointer implementing [`ReflectBundle::remove()`].
pub remove: fn(&mut EntityWorldMut),
}
impl ReflectBundleFns {
/// Get the default set of [`ReflectBundleFns`] for a specific bundle type using its
/// [`FromType`] implementation.
///
/// This is useful if you want to start with the default implementation before overriding some
/// of the functions to create a custom implementation.
pub fn new<T: Bundle + Reflect + FromReflect>() -> Self {
<ReflectBundle as FromType<T>>::from_type().0
}
}
impl ReflectBundle {
/// Insert a reflected [`Bundle`] into the entity like [`insert()`](EntityWorldMut::insert).
pub fn insert(
&self,
entity: &mut EntityWorldMut,
bundle: &dyn Reflect,
registry: &TypeRegistry,
) {
(self.0.insert)(entity, bundle, registry);
}
/// Uses reflection to set the value of this [`Bundle`] type in the entity to the given value.
///
/// # Panics
///
/// Panics if there is no [`Bundle`] of the given type.
pub fn apply<'a>(
&self,
entity: impl Into<EntityMut<'a>>,
bundle: &dyn Reflect,
registry: &TypeRegistry,
) {
(self.0.apply)(entity.into(), bundle, registry);
}
/// Uses reflection to set the value of this [`Bundle`] type in the entity to the given value or insert a new one if it does not exist.
pub fn apply_or_insert(
&self,
entity: &mut EntityWorldMut,
bundle: &dyn Reflect,
registry: &TypeRegistry,
) {
(self.0.apply_or_insert)(entity, bundle, registry);
}
/// Removes this [`Bundle`] type from the entity. Does nothing if it doesn't exist.
pub fn remove(&self, entity: &mut EntityWorldMut) {
(self.0.remove)(entity);
}
/// Create a custom implementation of [`ReflectBundle`].
///
/// This is an advanced feature,
/// useful for scripting implementations,
/// that should not be used by most users
/// unless you know what you are doing.
///
/// Usually you should derive [`Reflect`] and add the `#[reflect(Bundle)]` bundle
/// to generate a [`ReflectBundle`] implementation automatically.
///
/// See [`ReflectBundleFns`] for more information.
pub fn new(fns: ReflectBundleFns) -> Self {
Self(fns)
}
/// The underlying function pointers implementing methods on `ReflectBundle`.
///
/// This is useful when you want to keep track locally of an individual
/// function pointer.
///
/// Calling [`TypeRegistry::get`] followed by
/// [`TypeRegistration::data::<ReflectBundle>`] can be costly if done several
/// times per frame. Consider cloning [`ReflectBundle`] and keeping it
/// between frames, cloning a `ReflectBundle` is very cheap.
///
/// If you only need a subset of the methods on `ReflectBundle`,
/// use `fn_pointers` to get the underlying [`ReflectBundleFns`]
/// and copy the subset of function pointers you care about.
///
/// [`TypeRegistration::data::<ReflectBundle>`]: bevy_reflect::TypeRegistration::data
pub fn fn_pointers(&self) -> &ReflectBundleFns {
&self.0
}
}
impl<B: Bundle + Reflect> FromType<B> for ReflectBundle {
fn from_type() -> Self {
ReflectBundle(ReflectBundleFns {
insert: |entity, reflected_bundle, registry| {
let bundle = entity.world_scope(|world| {
from_reflect_with_fallback::<B>(reflected_bundle, world, registry)
});
entity.insert(bundle);
},
apply: |mut entity, reflected_bundle, registry| {
if let Some(reflect_component) =
registry.get_type_data::<ReflectComponent>(TypeId::of::<B>())
{
reflect_component.apply(entity, reflected_bundle);
} else {
match reflected_bundle.reflect_ref() {
ReflectRef::Struct(bundle) => bundle
.iter_fields()
.for_each(|field| apply_field(&mut entity, field, registry)),
ReflectRef::Tuple(bundle) => bundle
.iter_fields()
.for_each(|field| apply_field(&mut entity, field, registry)),
_ => panic!(
"expected bundle `{}` to be named struct or tuple",
// FIXME: once we have unique reflect, use `TypePath`.
std::any::type_name::<B>(),
),
}
}
},
apply_or_insert: |entity, reflected_bundle, registry| {
if let Some(reflect_component) =
registry.get_type_data::<ReflectComponent>(TypeId::of::<B>())
{
reflect_component.apply_or_insert(entity, reflected_bundle, registry);
} else {
match reflected_bundle.reflect_ref() {
ReflectRef::Struct(bundle) => bundle
.iter_fields()
.for_each(|field| apply_or_insert_field(entity, field, registry)),
ReflectRef::Tuple(bundle) => bundle
.iter_fields()
.for_each(|field| apply_or_insert_field(entity, field, registry)),
_ => panic!(
"expected bundle `{}` to be named struct or tuple",
// FIXME: once we have unique reflect, use `TypePath`.
std::any::type_name::<B>(),
),
}
}
},
remove: |entity| {
entity.remove::<B>();
},
})
}
}
fn apply_field(entity: &mut EntityMut, field: &dyn Reflect, registry: &TypeRegistry) {
if let Some(reflect_component) = registry.get_type_data::<ReflectComponent>(field.type_id()) {
reflect_component.apply(entity.reborrow(), field);
} else if let Some(reflect_bundle) = registry.get_type_data::<ReflectBundle>(field.type_id()) {
reflect_bundle.apply(entity.reborrow(), field, registry);
} else {
panic!(
"no `ReflectComponent` nor `ReflectBundle` registration found for `{}`",
field.reflect_type_path()
);
}
}
fn apply_or_insert_field(
entity: &mut EntityWorldMut,
field: &dyn Reflect,
registry: &TypeRegistry,
) {
if let Some(reflect_component) = registry.get_type_data::<ReflectComponent>(field.type_id()) {
reflect_component.apply_or_insert(entity, field, registry);
} else if let Some(reflect_bundle) = registry.get_type_data::<ReflectBundle>(field.type_id()) {
reflect_bundle.apply_or_insert(entity, field, registry);
} else {
let is_component = entity
.world()
.components()
.get_id(field.type_id())
.is_some();
if is_component {
panic!(
"no `ReflectComponent` registration found for `{}`",
field.reflect_type_path(),
);
} else {
panic!(
"no `ReflectBundle` registration found for `{}`",
field.reflect_type_path(),
)
}
}
}