bevy/crates/bevy_ecs/src/query/fetch.rs
Joseph 2e2f89869b
Expose query accesses (#11700)
# Objective

It would be useful to be able to inspect a `QueryState`'s accesses so we
can detect when the data it accesses changes without having to iterate
it. However there are two things preventing this:

* These accesses are unnecessarily encapsulated.
* `Has<T>` indirectly accesses `T`, but does not register it.

## Solution

* Expose accesses and matches used by `QueryState`.
* Add the notion of "archetypal" accesses, which are not accessed
directly, but whose presence in an archetype affects a query result.

---------

Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
2024-02-10 15:22:07 +00:00

1823 lines
56 KiB
Rust

use crate::{
archetype::Archetype,
change_detection::{Ticks, TicksMut},
component::{Component, ComponentId, ComponentStorage, StorageType, Tick},
entity::Entity,
query::{Access, DebugCheckedUnwrap, FilteredAccess, WorldQuery},
storage::{ComponentSparseSet, Table, TableRow},
world::{
unsafe_world_cell::UnsafeWorldCell, EntityMut, EntityRef, FilteredEntityMut,
FilteredEntityRef, Mut, Ref, World,
},
};
use bevy_ptr::{ThinSlicePtr, UnsafeCellDeref};
use bevy_utils::all_tuples;
use std::{cell::UnsafeCell, marker::PhantomData};
/// Types that can be fetched from a [`World`] using a [`Query`].
///
/// There are many types that natively implement this trait:
///
/// - **Component references.**
/// Fetches a component by reference (immutably or mutably).
/// - **`QueryData` tuples.**
/// If every element of a tuple implements `QueryData`, then the tuple itself also implements the same trait.
/// This enables a single `Query` to access multiple components.
/// Due to the current lack of variadic generics in Rust, the trait has been implemented for tuples from 0 to 15 elements,
/// but nesting of tuples allows infinite `WorldQuery`s.
/// - **[`Entity`].**
/// Gets the identifier of the queried entity.
/// - **[`Option`].**
/// By default, a world query only tests entities that have the matching component types.
/// Wrapping it into an `Option` will increase the query search space, and it will return `None` if an entity doesn't satisfy the `WorldQuery`.
/// - **[`AnyOf`].**
/// Equivalent to wrapping each world query inside it into an `Option`.
/// - **[`Ref`].**
/// Similar to change detection filters but it is used as a query fetch parameter.
/// It exposes methods to check for changes to the wrapped component.
/// - **[`Has`].**
/// Returns a bool indicating whether the entity has the specified component.
///
/// Implementing the trait manually can allow for a fundamentally new type of behavior.
///
/// # Trait derivation
///
/// Query design can be easily structured by deriving `QueryData` for custom types.
/// Despite the added complexity, this approach has several advantages over using `QueryData` tuples.
/// The most relevant improvements are:
///
/// - Reusability across multiple systems.
/// - There is no need to destructure a tuple since all fields are named.
/// - Subqueries can be composed together to create a more complex query.
/// - Methods can be implemented for the query items.
/// - There is no hardcoded limit on the number of elements.
///
/// This trait can only be derived for structs, if each field also implements `QueryData`.
///
/// ```
/// # use bevy_ecs::prelude::*;
/// use bevy_ecs::query::QueryData;
/// #
/// # #[derive(Component)]
/// # struct ComponentA;
/// # #[derive(Component)]
/// # struct ComponentB;
///
/// #[derive(QueryData)]
/// struct MyQuery {
/// entity: Entity,
/// // It is required that all reference lifetimes are explicitly annotated, just like in any
/// // struct. Each lifetime should be 'static.
/// component_a: &'static ComponentA,
/// component_b: &'static ComponentB,
/// }
///
/// fn my_system(query: Query<MyQuery>) {
/// for q in &query {
/// q.component_a;
/// }
/// }
/// # bevy_ecs::system::assert_is_system(my_system);
/// ```
///
/// ## Macro expansion
///
/// Expanding the macro will declare one or three additional structs, depending on whether or not the struct is marked as mutable.
/// For a struct named `X`, the additional structs will be:
///
/// |Struct name|`mutable` only|Description|
/// |:---:|:---:|---|
/// |`XItem`|---|The type of the query item for `X`|
/// |`XReadOnlyItem`|✓|The type of the query item for `XReadOnly`|
/// |`XReadOnly`|✓|[`ReadOnly`] variant of `X`|
///
/// ## Adding mutable references
///
/// Simply adding mutable references to a derived `QueryData` will result in a compilation error:
///
/// ```compile_fail
/// # use bevy_ecs::prelude::*;
/// # use bevy_ecs::query::QueryData;
/// #
/// # #[derive(Component)]
/// # struct ComponentA;
/// #
/// #[derive(QueryData)]
/// struct CustomQuery {
/// component_a: &'static mut ComponentA,
/// }
/// ```
///
/// To grant mutable access to components, the struct must be marked with the `#[query_data(mutable)]` attribute.
/// This will also create three more structs that will be used for accessing the query immutably (see table above).
///
/// ```
/// # use bevy_ecs::prelude::*;
/// # use bevy_ecs::query::QueryData;
/// #
/// # #[derive(Component)]
/// # struct ComponentA;
/// #
/// #[derive(QueryData)]
/// #[query_data(mutable)]
/// struct CustomQuery {
/// component_a: &'static mut ComponentA,
/// }
/// ```
///
/// ## Adding methods to query items
///
/// It is possible to add methods to query items in order to write reusable logic about related components.
/// This will often make systems more readable because low level logic is moved out from them.
/// It is done by adding `impl` blocks with methods for the `-Item` or `-ReadOnlyItem` generated structs.
///
/// ```
/// # use bevy_ecs::prelude::*;
/// # use bevy_ecs::query::QueryData;
/// #
/// #[derive(Component)]
/// struct Health(f32);
///
/// #[derive(Component)]
/// struct Buff(f32);
///
/// #[derive(QueryData)]
/// #[query_data(mutable)]
/// struct HealthQuery {
/// health: &'static mut Health,
/// buff: Option<&'static mut Buff>,
/// }
///
/// // `HealthQueryItem` is only available when accessing the query with mutable methods.
/// impl<'w> HealthQueryItem<'w> {
/// fn damage(&mut self, value: f32) {
/// self.health.0 -= value;
/// }
///
/// fn total(&self) -> f32 {
/// self.health.0 + self.buff.as_deref().map_or(0.0, |Buff(buff)| *buff)
/// }
/// }
///
/// // `HealthQueryReadOnlyItem` is only available when accessing the query with immutable methods.
/// impl<'w> HealthQueryReadOnlyItem<'w> {
/// fn total(&self) -> f32 {
/// self.health.0 + self.buff.map_or(0.0, |Buff(buff)| *buff)
/// }
/// }
///
/// fn my_system(mut health_query: Query<HealthQuery>) {
/// // The item returned by the iterator is of type `HealthQueryReadOnlyItem`.
/// for health in health_query.iter() {
/// println!("Total: {}", health.total());
/// }
/// // The item returned by the iterator is of type `HealthQueryItem`.
/// for mut health in &mut health_query {
/// health.damage(1.0);
/// println!("Total (mut): {}", health.total());
/// }
/// }
/// # bevy_ecs::system::assert_is_system(my_system);
/// ```
///
/// ## Deriving traits for query items
///
/// The `QueryData` derive macro does not automatically implement the traits of the struct to the query item types.
/// Something similar can be done by using the `#[query_data(derive(...))]` attribute.
/// This will apply the listed derivable traits to the query item structs.
///
/// ```
/// # use bevy_ecs::prelude::*;
/// # use bevy_ecs::query::QueryData;
/// #
/// # #[derive(Component, Debug)]
/// # struct ComponentA;
/// #
/// #[derive(QueryData)]
/// #[query_data(mutable, derive(Debug))]
/// struct CustomQuery {
/// component_a: &'static ComponentA,
/// }
///
/// // This function statically checks that `T` implements `Debug`.
/// fn assert_debug<T: std::fmt::Debug>() {}
///
/// assert_debug::<CustomQueryItem>();
/// assert_debug::<CustomQueryReadOnlyItem>();
/// ```
///
/// ## Query composition
///
/// It is possible to use any `QueryData` as a field of another one.
/// This means that a `QueryData` can also be used as a subquery, potentially in multiple places.
///
/// ```
/// # use bevy_ecs::prelude::*;
/// # use bevy_ecs::query::QueryData;
/// #
/// # #[derive(Component)]
/// # struct ComponentA;
/// # #[derive(Component)]
/// # struct ComponentB;
/// # #[derive(Component)]
/// # struct ComponentC;
/// #
/// #[derive(QueryData)]
/// struct SubQuery {
/// component_a: &'static ComponentA,
/// component_b: &'static ComponentB,
/// }
///
/// #[derive(QueryData)]
/// struct MyQuery {
/// subquery: SubQuery,
/// component_c: &'static ComponentC,
/// }
/// ```
///
/// # Generic Queries
///
/// When writing generic code, it is often necessary to use [`PhantomData`]
/// to constrain type parameters. Since `QueryData` is implemented for all
/// `PhantomData<T>` types, this pattern can be used with this macro.
///
/// ```
/// # use bevy_ecs::{prelude::*, query::QueryData};
/// # use std::marker::PhantomData;
/// #[derive(QueryData)]
/// pub struct GenericQuery<T> {
/// id: Entity,
/// marker: PhantomData<T>,
/// }
/// # fn my_system(q: Query<GenericQuery<()>>) {}
/// # bevy_ecs::system::assert_is_system(my_system);
/// ```
///
/// # Safety
///
/// Component access of `Self::ReadOnly` must be a subset of `Self`
/// and `Self::ReadOnly` must match exactly the same archetypes/tables as `Self`
///
/// [`Query`]: crate::system::Query
/// [`ReadOnly`]: Self::ReadOnly
pub unsafe trait QueryData: WorldQuery {
/// The read-only variant of this [`QueryData`], which satisfies the [`ReadOnlyQueryData`] trait.
type ReadOnly: ReadOnlyQueryData<State = <Self as WorldQuery>::State>;
}
/// A [`QueryData`] that is read only.
///
/// # Safety
///
/// This must only be implemented for read-only [`QueryData`]'s.
pub unsafe trait ReadOnlyQueryData: QueryData<ReadOnly = Self> {}
/// The item type returned when a [`WorldQuery`] is iterated over
pub type QueryItem<'w, Q> = <Q as WorldQuery>::Item<'w>;
/// The read-only variant of the item type returned when a [`QueryData`] is iterated over immutably
pub type ROQueryItem<'w, D> = QueryItem<'w, <D as QueryData>::ReadOnly>;
/// SAFETY:
/// `update_component_access` and `update_archetype_component_access` do nothing.
/// This is sound because `fetch` does not access components.
unsafe impl WorldQuery for Entity {
type Item<'w> = Entity;
type Fetch<'w> = ();
type State = ();
fn shrink<'wlong: 'wshort, 'wshort>(item: Self::Item<'wlong>) -> Self::Item<'wshort> {
item
}
unsafe fn init_fetch<'w>(
_world: UnsafeWorldCell<'w>,
_state: &Self::State,
_last_run: Tick,
_this_run: Tick,
) -> Self::Fetch<'w> {
}
const IS_DENSE: bool = true;
#[inline]
unsafe fn set_archetype<'w>(
_fetch: &mut Self::Fetch<'w>,
_state: &Self::State,
_archetype: &'w Archetype,
_table: &Table,
) {
}
#[inline]
unsafe fn set_table<'w>(_fetch: &mut Self::Fetch<'w>, _state: &Self::State, _table: &'w Table) {
}
#[inline(always)]
unsafe fn fetch<'w>(
_fetch: &mut Self::Fetch<'w>,
entity: Entity,
_table_row: TableRow,
) -> Self::Item<'w> {
entity
}
fn update_component_access(_state: &Self::State, _access: &mut FilteredAccess<ComponentId>) {}
fn init_state(_world: &mut World) {}
fn get_state(_world: &World) -> Option<()> {
Some(())
}
fn matches_component_set(
_state: &Self::State,
_set_contains_id: &impl Fn(ComponentId) -> bool,
) -> bool {
true
}
}
/// SAFETY: `Self` is the same as `Self::ReadOnly`
unsafe impl QueryData for Entity {
type ReadOnly = Self;
}
/// SAFETY: access is read only
unsafe impl ReadOnlyQueryData for Entity {}
/// SAFETY:
/// `fetch` accesses all components in a readonly way.
/// This is sound because `update_component_access` and `update_archetype_component_access` set read access for all components and panic when appropriate.
/// Filters are unchanged.
unsafe impl<'a> WorldQuery for EntityRef<'a> {
type Item<'w> = EntityRef<'w>;
type Fetch<'w> = UnsafeWorldCell<'w>;
type State = ();
fn shrink<'wlong: 'wshort, 'wshort>(item: Self::Item<'wlong>) -> Self::Item<'wshort> {
item
}
unsafe fn init_fetch<'w>(
world: UnsafeWorldCell<'w>,
_state: &Self::State,
_last_run: Tick,
_this_run: Tick,
) -> Self::Fetch<'w> {
world
}
const IS_DENSE: bool = true;
#[inline]
unsafe fn set_archetype<'w>(
_fetch: &mut Self::Fetch<'w>,
_state: &Self::State,
_archetype: &'w Archetype,
_table: &Table,
) {
}
#[inline]
unsafe fn set_table<'w>(_fetch: &mut Self::Fetch<'w>, _state: &Self::State, _table: &'w Table) {
}
#[inline(always)]
unsafe fn fetch<'w>(
world: &mut Self::Fetch<'w>,
entity: Entity,
_table_row: TableRow,
) -> Self::Item<'w> {
// SAFETY: `fetch` must be called with an entity that exists in the world
let cell = world.get_entity(entity).debug_checked_unwrap();
// SAFETY: Read-only access to every component has been registered.
EntityRef::new(cell)
}
fn update_component_access(_state: &Self::State, access: &mut FilteredAccess<ComponentId>) {
assert!(
!access.access().has_any_write(),
"EntityRef conflicts with a previous access in this query. Shared access cannot coincide with exclusive access.",
);
access.read_all();
}
fn init_state(_world: &mut World) {}
fn get_state(_world: &World) -> Option<()> {
Some(())
}
fn matches_component_set(
_state: &Self::State,
_set_contains_id: &impl Fn(ComponentId) -> bool,
) -> bool {
true
}
}
/// SAFETY: `Self` is the same as `Self::ReadOnly`
unsafe impl<'a> QueryData for EntityRef<'a> {
type ReadOnly = Self;
}
/// SAFETY: access is read only
unsafe impl ReadOnlyQueryData for EntityRef<'_> {}
/// SAFETY: The accesses of `Self::ReadOnly` are a subset of the accesses of `Self`
unsafe impl<'a> WorldQuery for EntityMut<'a> {
type Item<'w> = EntityMut<'w>;
type Fetch<'w> = UnsafeWorldCell<'w>;
type State = ();
fn shrink<'wlong: 'wshort, 'wshort>(item: Self::Item<'wlong>) -> Self::Item<'wshort> {
item
}
unsafe fn init_fetch<'w>(
world: UnsafeWorldCell<'w>,
_state: &Self::State,
_last_run: Tick,
_this_run: Tick,
) -> Self::Fetch<'w> {
world
}
const IS_DENSE: bool = true;
#[inline]
unsafe fn set_archetype<'w>(
_fetch: &mut Self::Fetch<'w>,
_state: &Self::State,
_archetype: &'w Archetype,
_table: &Table,
) {
}
#[inline]
unsafe fn set_table<'w>(_fetch: &mut Self::Fetch<'w>, _state: &Self::State, _table: &'w Table) {
}
#[inline(always)]
unsafe fn fetch<'w>(
world: &mut Self::Fetch<'w>,
entity: Entity,
_table_row: TableRow,
) -> Self::Item<'w> {
// SAFETY: `fetch` must be called with an entity that exists in the world
let cell = world.get_entity(entity).debug_checked_unwrap();
// SAFETY: mutable access to every component has been registered.
EntityMut::new(cell)
}
fn update_component_access(_state: &Self::State, access: &mut FilteredAccess<ComponentId>) {
assert!(
!access.access().has_any_read(),
"EntityMut conflicts with a previous access in this query. Exclusive access cannot coincide with any other accesses.",
);
access.write_all();
}
fn init_state(_world: &mut World) {}
fn get_state(_world: &World) -> Option<()> {
Some(())
}
fn matches_component_set(
_state: &Self::State,
_set_contains_id: &impl Fn(ComponentId) -> bool,
) -> bool {
true
}
}
/// SAFETY: access of `EntityRef` is a subset of `EntityMut`
unsafe impl<'a> QueryData for EntityMut<'a> {
type ReadOnly = EntityRef<'a>;
}
/// SAFETY: The accesses of `Self::ReadOnly` are a subset of the accesses of `Self`
unsafe impl<'a> WorldQuery for FilteredEntityRef<'a> {
type Fetch<'w> = (UnsafeWorldCell<'w>, Access<ComponentId>);
type Item<'w> = FilteredEntityRef<'w>;
type State = FilteredAccess<ComponentId>;
fn shrink<'wlong: 'wshort, 'wshort>(item: Self::Item<'wlong>) -> Self::Item<'wshort> {
item
}
const IS_DENSE: bool = false;
unsafe fn init_fetch<'w>(
world: UnsafeWorldCell<'w>,
_state: &Self::State,
_last_run: Tick,
_this_run: Tick,
) -> Self::Fetch<'w> {
let mut access = Access::default();
access.read_all();
(world, access)
}
#[inline]
unsafe fn set_archetype<'w>(
fetch: &mut Self::Fetch<'w>,
state: &Self::State,
archetype: &'w Archetype,
_table: &Table,
) {
let mut access = Access::default();
state.access.reads().for_each(|id| {
if archetype.contains(id) {
access.add_read(id);
}
});
fetch.1 = access;
}
#[inline]
unsafe fn set_table<'w>(fetch: &mut Self::Fetch<'w>, state: &Self::State, table: &'w Table) {
let mut access = Access::default();
state.access.reads().for_each(|id| {
if table.has_column(id) {
access.add_read(id);
}
});
fetch.1 = access;
}
#[inline]
fn set_access<'w>(state: &mut Self::State, access: &FilteredAccess<ComponentId>) {
*state = access.clone();
state.access_mut().clear_writes();
}
#[inline(always)]
unsafe fn fetch<'w>(
(world, access): &mut Self::Fetch<'w>,
entity: Entity,
_table_row: TableRow,
) -> Self::Item<'w> {
// SAFETY: `fetch` must be called with an entity that exists in the world
let cell = world.get_entity(entity).debug_checked_unwrap();
// SAFETY: mutable access to every component has been registered.
FilteredEntityRef::new(cell, access.clone())
}
fn update_component_access(
state: &Self::State,
filtered_access: &mut FilteredAccess<ComponentId>,
) {
assert!(
filtered_access.access().is_compatible(&state.access),
"FilteredEntityRef conflicts with a previous access in this query. Exclusive access cannot coincide with any other accesses.",
);
filtered_access.access.extend(&state.access);
}
fn init_state(_world: &mut World) -> Self::State {
FilteredAccess::default()
}
fn get_state(_world: &World) -> Option<Self::State> {
Some(FilteredAccess::default())
}
fn matches_component_set(
_state: &Self::State,
_set_contains_id: &impl Fn(ComponentId) -> bool,
) -> bool {
true
}
}
/// SAFETY: `Self` is the same as `Self::ReadOnly`
unsafe impl<'a> QueryData for FilteredEntityRef<'a> {
type ReadOnly = Self;
}
/// SAFETY: Access is read-only.
unsafe impl ReadOnlyQueryData for FilteredEntityRef<'_> {}
/// SAFETY: The accesses of `Self::ReadOnly` are a subset of the accesses of `Self`
unsafe impl<'a> WorldQuery for FilteredEntityMut<'a> {
type Fetch<'w> = (UnsafeWorldCell<'w>, Access<ComponentId>);
type Item<'w> = FilteredEntityMut<'w>;
type State = FilteredAccess<ComponentId>;
fn shrink<'wlong: 'wshort, 'wshort>(item: Self::Item<'wlong>) -> Self::Item<'wshort> {
item
}
const IS_DENSE: bool = false;
unsafe fn init_fetch<'w>(
world: UnsafeWorldCell<'w>,
_state: &Self::State,
_last_run: Tick,
_this_run: Tick,
) -> Self::Fetch<'w> {
let mut access = Access::default();
access.write_all();
(world, access)
}
#[inline]
unsafe fn set_archetype<'w>(
fetch: &mut Self::Fetch<'w>,
state: &Self::State,
archetype: &'w Archetype,
_table: &Table,
) {
let mut access = Access::default();
state.access.reads().for_each(|id| {
if archetype.contains(id) {
access.add_read(id);
}
});
state.access.writes().for_each(|id| {
if archetype.contains(id) {
access.add_write(id);
}
});
fetch.1 = access;
}
#[inline]
unsafe fn set_table<'w>(fetch: &mut Self::Fetch<'w>, state: &Self::State, table: &'w Table) {
let mut access = Access::default();
state.access.reads().for_each(|id| {
if table.has_column(id) {
access.add_read(id);
}
});
state.access.writes().for_each(|id| {
if table.has_column(id) {
access.add_write(id);
}
});
fetch.1 = access;
}
#[inline]
fn set_access<'w>(state: &mut Self::State, access: &FilteredAccess<ComponentId>) {
*state = access.clone();
}
#[inline(always)]
unsafe fn fetch<'w>(
(world, access): &mut Self::Fetch<'w>,
entity: Entity,
_table_row: TableRow,
) -> Self::Item<'w> {
// SAFETY: `fetch` must be called with an entity that exists in the world
let cell = world.get_entity(entity).debug_checked_unwrap();
// SAFETY: mutable access to every component has been registered.
FilteredEntityMut::new(cell, access.clone())
}
fn update_component_access(
state: &Self::State,
filtered_access: &mut FilteredAccess<ComponentId>,
) {
assert!(
filtered_access.access().is_compatible(&state.access),
"FilteredEntityMut conflicts with a previous access in this query. Exclusive access cannot coincide with any other accesses.",
);
filtered_access.access.extend(&state.access);
}
fn init_state(_world: &mut World) -> Self::State {
FilteredAccess::default()
}
fn get_state(_world: &World) -> Option<Self::State> {
Some(FilteredAccess::default())
}
fn matches_component_set(
_state: &Self::State,
_set_contains_id: &impl Fn(ComponentId) -> bool,
) -> bool {
true
}
}
/// SAFETY: access of `FilteredEntityRef` is a subset of `FilteredEntityMut`
unsafe impl<'a> QueryData for FilteredEntityMut<'a> {
type ReadOnly = FilteredEntityRef<'a>;
}
#[doc(hidden)]
pub struct ReadFetch<'w, T> {
// T::Storage = TableStorage
table_components: Option<ThinSlicePtr<'w, UnsafeCell<T>>>,
// T::Storage = SparseStorage
sparse_set: Option<&'w ComponentSparseSet>,
}
impl<T> Clone for ReadFetch<'_, T> {
fn clone(&self) -> Self {
*self
}
}
impl<T> Copy for ReadFetch<'_, T> {}
/// SAFETY:
/// `fetch` accesses a single component in a readonly way.
/// This is sound because `update_component_access` and `update_archetype_component_access` add read access for that component and panic when appropriate.
/// `update_component_access` adds a `With` filter for a component.
/// This is sound because `matches_component_set` returns whether the set contains that component.
unsafe impl<T: Component> WorldQuery for &T {
type Item<'w> = &'w T;
type Fetch<'w> = ReadFetch<'w, T>;
type State = ComponentId;
fn shrink<'wlong: 'wshort, 'wshort>(item: &'wlong T) -> &'wshort T {
item
}
#[inline]
unsafe fn init_fetch<'w>(
world: UnsafeWorldCell<'w>,
&component_id: &ComponentId,
_last_run: Tick,
_this_run: Tick,
) -> ReadFetch<'w, T> {
ReadFetch {
table_components: None,
sparse_set: (T::Storage::STORAGE_TYPE == StorageType::SparseSet).then(|| {
world
// SAFETY: The underlying type associated with `component_id` is `T`,
// which we are allowed to access since we registered it in `update_archetype_component_access`.
// Note that we do not actually access any components in this function, we just get a shared
// reference to the sparse set, which is used to access the components in `Self::fetch`.
.storages()
.sparse_sets
.get(component_id)
.debug_checked_unwrap()
}),
}
}
const IS_DENSE: bool = {
match T::Storage::STORAGE_TYPE {
StorageType::Table => true,
StorageType::SparseSet => false,
}
};
#[inline]
unsafe fn set_archetype<'w>(
fetch: &mut ReadFetch<'w, T>,
component_id: &ComponentId,
_archetype: &'w Archetype,
table: &'w Table,
) {
if Self::IS_DENSE {
Self::set_table(fetch, component_id, table);
}
}
#[inline]
unsafe fn set_table<'w>(
fetch: &mut ReadFetch<'w, T>,
&component_id: &ComponentId,
table: &'w Table,
) {
fetch.table_components = Some(
table
.get_column(component_id)
.debug_checked_unwrap()
.get_data_slice()
.into(),
);
}
#[inline(always)]
unsafe fn fetch<'w>(
fetch: &mut Self::Fetch<'w>,
entity: Entity,
table_row: TableRow,
) -> Self::Item<'w> {
match T::Storage::STORAGE_TYPE {
StorageType::Table => fetch
.table_components
.debug_checked_unwrap()
.get(table_row.as_usize())
.deref(),
StorageType::SparseSet => fetch
.sparse_set
.debug_checked_unwrap()
.get(entity)
.debug_checked_unwrap()
.deref(),
}
}
fn update_component_access(
&component_id: &ComponentId,
access: &mut FilteredAccess<ComponentId>,
) {
assert!(
!access.access().has_write(component_id),
"&{} conflicts with a previous access in this query. Shared access cannot coincide with exclusive access.",
std::any::type_name::<T>(),
);
access.add_read(component_id);
}
fn init_state(world: &mut World) -> ComponentId {
world.init_component::<T>()
}
fn get_state(world: &World) -> Option<Self::State> {
world.component_id::<T>()
}
fn matches_component_set(
&state: &ComponentId,
set_contains_id: &impl Fn(ComponentId) -> bool,
) -> bool {
set_contains_id(state)
}
}
/// SAFETY: `Self` is the same as `Self::ReadOnly`
unsafe impl<T: Component> QueryData for &T {
type ReadOnly = Self;
}
/// SAFETY: access is read only
unsafe impl<T: Component> ReadOnlyQueryData for &T {}
#[doc(hidden)]
pub struct RefFetch<'w, T> {
// T::Storage = TableStorage
table_data: Option<(
ThinSlicePtr<'w, UnsafeCell<T>>,
ThinSlicePtr<'w, UnsafeCell<Tick>>,
ThinSlicePtr<'w, UnsafeCell<Tick>>,
)>,
// T::Storage = SparseStorage
sparse_set: Option<&'w ComponentSparseSet>,
last_run: Tick,
this_run: Tick,
}
impl<T> Clone for RefFetch<'_, T> {
fn clone(&self) -> Self {
*self
}
}
impl<T> Copy for RefFetch<'_, T> {}
/// SAFETY:
/// `fetch` accesses a single component in a readonly way.
/// This is sound because `update_component_access` and `update_archetype_component_access` add read access for that component and panic when appropriate.
/// `update_component_access` adds a `With` filter for a component.
/// This is sound because `matches_component_set` returns whether the set contains that component.
unsafe impl<'__w, T: Component> WorldQuery for Ref<'__w, T> {
type Item<'w> = Ref<'w, T>;
type Fetch<'w> = RefFetch<'w, T>;
type State = ComponentId;
fn shrink<'wlong: 'wshort, 'wshort>(item: Ref<'wlong, T>) -> Ref<'wshort, T> {
item
}
#[inline]
unsafe fn init_fetch<'w>(
world: UnsafeWorldCell<'w>,
&component_id: &ComponentId,
last_run: Tick,
this_run: Tick,
) -> RefFetch<'w, T> {
RefFetch {
table_data: None,
sparse_set: (T::Storage::STORAGE_TYPE == StorageType::SparseSet).then(|| {
world
// SAFETY: See &T::init_fetch.
.storages()
.sparse_sets
.get(component_id)
.debug_checked_unwrap()
}),
last_run,
this_run,
}
}
const IS_DENSE: bool = {
match T::Storage::STORAGE_TYPE {
StorageType::Table => true,
StorageType::SparseSet => false,
}
};
#[inline]
unsafe fn set_archetype<'w>(
fetch: &mut RefFetch<'w, T>,
component_id: &ComponentId,
_archetype: &'w Archetype,
table: &'w Table,
) {
if Self::IS_DENSE {
Self::set_table(fetch, component_id, table);
}
}
#[inline]
unsafe fn set_table<'w>(
fetch: &mut RefFetch<'w, T>,
&component_id: &ComponentId,
table: &'w Table,
) {
let column = table.get_column(component_id).debug_checked_unwrap();
fetch.table_data = Some((
column.get_data_slice().into(),
column.get_added_ticks_slice().into(),
column.get_changed_ticks_slice().into(),
));
}
#[inline(always)]
unsafe fn fetch<'w>(
fetch: &mut Self::Fetch<'w>,
entity: Entity,
table_row: TableRow,
) -> Self::Item<'w> {
match T::Storage::STORAGE_TYPE {
StorageType::Table => {
let (table_components, added_ticks, changed_ticks) =
fetch.table_data.debug_checked_unwrap();
Ref {
value: table_components.get(table_row.as_usize()).deref(),
ticks: Ticks {
added: added_ticks.get(table_row.as_usize()).deref(),
changed: changed_ticks.get(table_row.as_usize()).deref(),
this_run: fetch.this_run,
last_run: fetch.last_run,
},
}
}
StorageType::SparseSet => {
let (component, ticks) = fetch
.sparse_set
.debug_checked_unwrap()
.get_with_ticks(entity)
.debug_checked_unwrap();
Ref {
value: component.deref(),
ticks: Ticks::from_tick_cells(ticks, fetch.last_run, fetch.this_run),
}
}
}
}
fn update_component_access(
&component_id: &ComponentId,
access: &mut FilteredAccess<ComponentId>,
) {
assert!(
!access.access().has_write(component_id),
"&{} conflicts with a previous access in this query. Shared access cannot coincide with exclusive access.",
std::any::type_name::<T>(),
);
access.add_read(component_id);
}
fn init_state(world: &mut World) -> ComponentId {
world.init_component::<T>()
}
fn get_state(world: &World) -> Option<Self::State> {
world.component_id::<T>()
}
fn matches_component_set(
&state: &ComponentId,
set_contains_id: &impl Fn(ComponentId) -> bool,
) -> bool {
set_contains_id(state)
}
}
/// SAFETY: `Self` is the same as `Self::ReadOnly`
unsafe impl<'__w, T: Component> QueryData for Ref<'__w, T> {
type ReadOnly = Self;
}
/// SAFETY: access is read only
unsafe impl<'__w, T: Component> ReadOnlyQueryData for Ref<'__w, T> {}
#[doc(hidden)]
pub struct WriteFetch<'w, T> {
// T::Storage = TableStorage
table_data: Option<(
ThinSlicePtr<'w, UnsafeCell<T>>,
ThinSlicePtr<'w, UnsafeCell<Tick>>,
ThinSlicePtr<'w, UnsafeCell<Tick>>,
)>,
// T::Storage = SparseStorage
sparse_set: Option<&'w ComponentSparseSet>,
last_run: Tick,
this_run: Tick,
}
impl<T> Clone for WriteFetch<'_, T> {
fn clone(&self) -> Self {
*self
}
}
impl<T> Copy for WriteFetch<'_, T> {}
/// SAFETY:
/// `fetch` accesses a single component mutably.
/// This is sound because `update_component_access` and `update_archetype_component_access` add write access for that component and panic when appropriate.
/// `update_component_access` adds a `With` filter for a component.
/// This is sound because `matches_component_set` returns whether the set contains that component.
unsafe impl<'__w, T: Component> WorldQuery for &'__w mut T {
type Item<'w> = Mut<'w, T>;
type Fetch<'w> = WriteFetch<'w, T>;
type State = ComponentId;
fn shrink<'wlong: 'wshort, 'wshort>(item: Mut<'wlong, T>) -> Mut<'wshort, T> {
item
}
#[inline]
unsafe fn init_fetch<'w>(
world: UnsafeWorldCell<'w>,
&component_id: &ComponentId,
last_run: Tick,
this_run: Tick,
) -> WriteFetch<'w, T> {
WriteFetch {
table_data: None,
sparse_set: (T::Storage::STORAGE_TYPE == StorageType::SparseSet).then(|| {
world
// SAFETY: See &T::init_fetch.
.storages()
.sparse_sets
.get(component_id)
.debug_checked_unwrap()
}),
last_run,
this_run,
}
}
const IS_DENSE: bool = {
match T::Storage::STORAGE_TYPE {
StorageType::Table => true,
StorageType::SparseSet => false,
}
};
#[inline]
unsafe fn set_archetype<'w>(
fetch: &mut WriteFetch<'w, T>,
component_id: &ComponentId,
_archetype: &'w Archetype,
table: &'w Table,
) {
if Self::IS_DENSE {
Self::set_table(fetch, component_id, table);
}
}
#[inline]
unsafe fn set_table<'w>(
fetch: &mut WriteFetch<'w, T>,
&component_id: &ComponentId,
table: &'w Table,
) {
let column = table.get_column(component_id).debug_checked_unwrap();
fetch.table_data = Some((
column.get_data_slice().into(),
column.get_added_ticks_slice().into(),
column.get_changed_ticks_slice().into(),
));
}
#[inline(always)]
unsafe fn fetch<'w>(
fetch: &mut Self::Fetch<'w>,
entity: Entity,
table_row: TableRow,
) -> Self::Item<'w> {
match T::Storage::STORAGE_TYPE {
StorageType::Table => {
let (table_components, added_ticks, changed_ticks) =
fetch.table_data.debug_checked_unwrap();
Mut {
value: table_components.get(table_row.as_usize()).deref_mut(),
ticks: TicksMut {
added: added_ticks.get(table_row.as_usize()).deref_mut(),
changed: changed_ticks.get(table_row.as_usize()).deref_mut(),
this_run: fetch.this_run,
last_run: fetch.last_run,
},
}
}
StorageType::SparseSet => {
let (component, ticks) = fetch
.sparse_set
.debug_checked_unwrap()
.get_with_ticks(entity)
.debug_checked_unwrap();
Mut {
value: component.assert_unique().deref_mut(),
ticks: TicksMut::from_tick_cells(ticks, fetch.last_run, fetch.this_run),
}
}
}
}
fn update_component_access(
&component_id: &ComponentId,
access: &mut FilteredAccess<ComponentId>,
) {
assert!(
!access.access().has_read(component_id),
"&mut {} conflicts with a previous access in this query. Mutable component access must be unique.",
std::any::type_name::<T>(),
);
access.add_write(component_id);
}
fn init_state(world: &mut World) -> ComponentId {
world.init_component::<T>()
}
fn get_state(world: &World) -> Option<Self::State> {
world.component_id::<T>()
}
fn matches_component_set(
&state: &ComponentId,
set_contains_id: &impl Fn(ComponentId) -> bool,
) -> bool {
set_contains_id(state)
}
}
/// SAFETY: access of `&T` is a subset of `&mut T`
unsafe impl<'__w, T: Component> QueryData for &'__w mut T {
type ReadOnly = &'__w T;
}
#[doc(hidden)]
pub struct OptionFetch<'w, T: WorldQuery> {
fetch: T::Fetch<'w>,
matches: bool,
}
impl<T: WorldQuery> Clone for OptionFetch<'_, T> {
fn clone(&self) -> Self {
Self {
fetch: self.fetch.clone(),
matches: self.matches,
}
}
}
/// SAFETY:
/// `fetch` might access any components that `T` accesses.
/// This is sound because `update_component_access` and `update_archetype_component_access` add the same accesses as `T`.
/// Filters are unchanged.
unsafe impl<T: WorldQuery> WorldQuery for Option<T> {
type Item<'w> = Option<T::Item<'w>>;
type Fetch<'w> = OptionFetch<'w, T>;
type State = T::State;
fn shrink<'wlong: 'wshort, 'wshort>(item: Self::Item<'wlong>) -> Self::Item<'wshort> {
item.map(T::shrink)
}
#[inline]
unsafe fn init_fetch<'w>(
world: UnsafeWorldCell<'w>,
state: &T::State,
last_run: Tick,
this_run: Tick,
) -> OptionFetch<'w, T> {
OptionFetch {
fetch: T::init_fetch(world, state, last_run, this_run),
matches: false,
}
}
const IS_DENSE: bool = T::IS_DENSE;
#[inline]
unsafe fn set_archetype<'w>(
fetch: &mut OptionFetch<'w, T>,
state: &T::State,
archetype: &'w Archetype,
table: &'w Table,
) {
fetch.matches = T::matches_component_set(state, &|id| archetype.contains(id));
if fetch.matches {
T::set_archetype(&mut fetch.fetch, state, archetype, table);
}
}
#[inline]
unsafe fn set_table<'w>(fetch: &mut OptionFetch<'w, T>, state: &T::State, table: &'w Table) {
fetch.matches = T::matches_component_set(state, &|id| table.has_column(id));
if fetch.matches {
T::set_table(&mut fetch.fetch, state, table);
}
}
#[inline(always)]
unsafe fn fetch<'w>(
fetch: &mut Self::Fetch<'w>,
entity: Entity,
table_row: TableRow,
) -> Self::Item<'w> {
fetch
.matches
.then(|| T::fetch(&mut fetch.fetch, entity, table_row))
}
fn update_component_access(state: &T::State, access: &mut FilteredAccess<ComponentId>) {
// FilteredAccess::add_[write,read] adds the component to the `with` filter.
// Those methods are called on `access` in `T::update_component_access`.
// But in `Option<T>`, we specifically don't filter on `T`,
// since `(Option<T>, &OtherComponent)` should be a valid item, even
// if `Option<T>` is `None`.
//
// We pass a clone of the `FilteredAccess` to `T`, and only update the `Access`
// using `extend_access` so that we can apply `T`'s component_access
// without updating the `with` filters of `access`.
let mut intermediate = access.clone();
T::update_component_access(state, &mut intermediate);
access.extend_access(&intermediate);
}
fn init_state(world: &mut World) -> T::State {
T::init_state(world)
}
fn get_state(world: &World) -> Option<Self::State> {
T::get_state(world)
}
fn matches_component_set(
_state: &T::State,
_set_contains_id: &impl Fn(ComponentId) -> bool,
) -> bool {
true
}
}
// SAFETY: defers to soundness of `T: WorldQuery` impl
unsafe impl<T: QueryData> QueryData for Option<T> {
type ReadOnly = Option<T::ReadOnly>;
}
/// SAFETY: [`OptionFetch`] is read only because `T` is read only
unsafe impl<T: ReadOnlyQueryData> ReadOnlyQueryData for Option<T> {}
/// Returns a bool that describes if an entity has the component `T`.
///
/// This can be used in a [`Query`](crate::system::Query) if you want to know whether or not entities
/// have the component `T` but don't actually care about the component's value.
///
/// # Footguns
///
/// Note that a `Query<Has<T>>` will match all existing entities.
/// Beware! Even if it matches all entities, it doesn't mean that `query.get(entity)`
/// will always return `Ok(bool)`.
///
/// In the case of a non-existent entity, such as a despawned one, it will return `Err`.
/// A workaround is to replace `query.get(entity).unwrap()` by
/// `query.get(entity).unwrap_or_default()`.
///
/// # Examples
///
/// ```
/// # use bevy_ecs::component::Component;
/// # use bevy_ecs::query::Has;
/// # use bevy_ecs::system::IntoSystem;
/// # use bevy_ecs::system::Query;
/// #
/// # #[derive(Component)]
/// # struct IsHungry;
/// # #[derive(Component)]
/// # struct Name { name: &'static str };
/// #
/// fn food_entity_system(query: Query<(&Name, Has<IsHungry>) >) {
/// for (name, is_hungry) in &query {
/// if is_hungry{
/// println!("{} would like some food.", name.name);
/// } else {
/// println!("{} has had sufficient.", name.name);
/// }
/// }
/// }
/// # bevy_ecs::system::assert_is_system(food_entity_system);
/// ```
///
/// ```
/// # use bevy_ecs::component::Component;
/// # use bevy_ecs::query::Has;
/// # use bevy_ecs::system::IntoSystem;
/// # use bevy_ecs::system::Query;
/// #
/// # #[derive(Component)]
/// # struct Alpha{has_beta: bool};
/// # #[derive(Component)]
/// # struct Beta { has_alpha: bool };
/// #
/// // Unlike `Option<&T>`, `Has<T>` is compatible with `&mut T`
/// // as it does not actually access any data.
/// fn alphabet_entity_system(mut alphas: Query<(&mut Alpha, Has<Beta>)>, mut betas: Query<(&mut Beta, Has<Alpha>)>) {
/// for (mut alpha, has_beta) in alphas.iter_mut() {
/// alpha.has_beta = has_beta;
/// }
/// for (mut beta, has_alpha) in betas.iter_mut() {
/// beta.has_alpha = has_alpha;
/// }
/// }
/// # bevy_ecs::system::assert_is_system(alphabet_entity_system);
/// ```
pub struct Has<T>(PhantomData<T>);
/// SAFETY:
/// `update_component_access` and `update_archetype_component_access` do nothing.
/// This is sound because `fetch` does not access components.
unsafe impl<T: Component> WorldQuery for Has<T> {
type Item<'w> = bool;
type Fetch<'w> = bool;
type State = ComponentId;
fn shrink<'wlong: 'wshort, 'wshort>(item: Self::Item<'wlong>) -> Self::Item<'wshort> {
item
}
#[inline]
unsafe fn init_fetch<'w>(
_world: UnsafeWorldCell<'w>,
_state: &Self::State,
_last_run: Tick,
_this_run: Tick,
) -> Self::Fetch<'w> {
false
}
const IS_DENSE: bool = {
match T::Storage::STORAGE_TYPE {
StorageType::Table => true,
StorageType::SparseSet => false,
}
};
#[inline]
unsafe fn set_archetype<'w>(
fetch: &mut Self::Fetch<'w>,
state: &Self::State,
archetype: &'w Archetype,
_table: &Table,
) {
*fetch = archetype.contains(*state);
}
#[inline]
unsafe fn set_table<'w>(fetch: &mut Self::Fetch<'w>, state: &Self::State, table: &'w Table) {
*fetch = table.has_column(*state);
}
#[inline(always)]
unsafe fn fetch<'w>(
fetch: &mut Self::Fetch<'w>,
_entity: Entity,
_table_row: TableRow,
) -> Self::Item<'w> {
*fetch
}
fn update_component_access(
&component_id: &Self::State,
access: &mut FilteredAccess<ComponentId>,
) {
access.access_mut().add_archetypal(component_id);
}
fn init_state(world: &mut World) -> ComponentId {
world.init_component::<T>()
}
fn get_state(world: &World) -> Option<Self::State> {
world.component_id::<T>()
}
fn matches_component_set(
_state: &Self::State,
_set_contains_id: &impl Fn(ComponentId) -> bool,
) -> bool {
// `Has<T>` always matches
true
}
}
/// SAFETY: `Self` is the same as `Self::ReadOnly`
unsafe impl<T: Component> QueryData for Has<T> {
type ReadOnly = Self;
}
/// SAFETY: [`Has`] is read only
unsafe impl<T: Component> ReadOnlyQueryData for Has<T> {}
/// The `AnyOf` query parameter fetches entities with any of the component types included in T.
///
/// `Query<AnyOf<(&A, &B, &mut C)>>` is equivalent to `Query<(Option<&A>, Option<&B>, Option<&mut C>), Or<(With<A>, With<B>, With<C>)>>`.
/// Each of the components in `T` is returned as an `Option`, as with `Option<A>` queries.
/// Entities are guaranteed to have at least one of the components in `T`.
pub struct AnyOf<T>(PhantomData<T>);
macro_rules! impl_tuple_query_data {
($(($name: ident, $state: ident)),*) => {
#[allow(non_snake_case)]
#[allow(clippy::unused_unit)]
// SAFETY: defers to soundness `$name: WorldQuery` impl
unsafe impl<$($name: QueryData),*> QueryData for ($($name,)*) {
type ReadOnly = ($($name::ReadOnly,)*);
}
/// SAFETY: each item in the tuple is read only
unsafe impl<$($name: ReadOnlyQueryData),*> ReadOnlyQueryData for ($($name,)*) {}
};
}
macro_rules! impl_anytuple_fetch {
($(($name: ident, $state: ident)),*) => {
#[allow(non_snake_case)]
#[allow(clippy::unused_unit)]
/// SAFETY:
/// `fetch` accesses are a subset of the subqueries' accesses
/// This is sound because `update_component_access` and `update_archetype_component_access` adds accesses according to the implementations of all the subqueries.
/// `update_component_access` replaces the filters with a disjunction where every element is a conjunction of the previous filters and the filters of one of the subqueries.
/// This is sound because `matches_component_set` returns a disjunction of the results of the subqueries' implementations.
unsafe impl<$($name: WorldQuery),*> WorldQuery for AnyOf<($($name,)*)> {
type Fetch<'w> = ($(($name::Fetch<'w>, bool),)*);
type Item<'w> = ($(Option<$name::Item<'w>>,)*);
type State = ($($name::State,)*);
fn shrink<'wlong: 'wshort, 'wshort>(item: Self::Item<'wlong>) -> Self::Item<'wshort> {
let ($($name,)*) = item;
($(
$name.map($name::shrink),
)*)
}
#[inline]
#[allow(clippy::unused_unit)]
unsafe fn init_fetch<'w>(_world: UnsafeWorldCell<'w>, state: &Self::State, _last_run: Tick, _this_run: Tick) -> Self::Fetch<'w> {
let ($($name,)*) = state;
($(($name::init_fetch(_world, $name, _last_run, _this_run), false),)*)
}
const IS_DENSE: bool = true $(&& $name::IS_DENSE)*;
#[inline]
unsafe fn set_archetype<'w>(
_fetch: &mut Self::Fetch<'w>,
_state: &Self::State,
_archetype: &'w Archetype,
_table: &'w Table
) {
let ($($name,)*) = _fetch;
let ($($state,)*) = _state;
$(
$name.1 = $name::matches_component_set($state, &|id| _archetype.contains(id));
if $name.1 {
$name::set_archetype(&mut $name.0, $state, _archetype, _table);
}
)*
}
#[inline]
unsafe fn set_table<'w>(_fetch: &mut Self::Fetch<'w>, _state: &Self::State, _table: &'w Table) {
let ($($name,)*) = _fetch;
let ($($state,)*) = _state;
$(
$name.1 = $name::matches_component_set($state, &|id| _table.has_column(id));
if $name.1 {
$name::set_table(&mut $name.0, $state, _table);
}
)*
}
#[inline(always)]
#[allow(clippy::unused_unit)]
unsafe fn fetch<'w>(
_fetch: &mut Self::Fetch<'w>,
_entity: Entity,
_table_row: TableRow
) -> Self::Item<'w> {
let ($($name,)*) = _fetch;
($(
$name.1.then(|| $name::fetch(&mut $name.0, _entity, _table_row)),
)*)
}
fn update_component_access(state: &Self::State, _access: &mut FilteredAccess<ComponentId>) {
let ($($name,)*) = state;
let mut _new_access = _access.clone();
let mut _not_first = false;
$(
if _not_first {
let mut intermediate = _access.clone();
$name::update_component_access($name, &mut intermediate);
_new_access.append_or(&intermediate);
_new_access.extend_access(&intermediate);
} else {
$name::update_component_access($name, &mut _new_access);
_new_access.required = _access.required.clone();
_not_first = true;
}
)*
*_access = _new_access;
}
fn init_state(_world: &mut World) -> Self::State {
($($name::init_state(_world),)*)
}
fn get_state(_world: &World) -> Option<Self::State> {
Some(($($name::get_state(_world)?,)*))
}
fn matches_component_set(_state: &Self::State, _set_contains_id: &impl Fn(ComponentId) -> bool) -> bool {
let ($($name,)*) = _state;
false $(|| $name::matches_component_set($name, _set_contains_id))*
}
}
#[allow(non_snake_case)]
#[allow(clippy::unused_unit)]
// SAFETY: defers to soundness of `$name: WorldQuery` impl
unsafe impl<$($name: QueryData),*> QueryData for AnyOf<($($name,)*)> {
type ReadOnly = AnyOf<($($name::ReadOnly,)*)>;
}
/// SAFETY: each item in the tuple is read only
unsafe impl<$($name: ReadOnlyQueryData),*> ReadOnlyQueryData for AnyOf<($($name,)*)> {}
};
}
all_tuples!(impl_tuple_query_data, 0, 15, F, S);
all_tuples!(impl_anytuple_fetch, 0, 15, F, S);
/// [`WorldQuery`] used to nullify queries by turning `Query<D>` into `Query<NopWorldQuery<D>>`
///
/// This will rarely be useful to consumers of `bevy_ecs`.
pub struct NopWorldQuery<D: QueryData>(PhantomData<D>);
/// SAFETY:
/// `update_component_access` and `update_archetype_component_access` do nothing.
/// This is sound because `fetch` does not access components.
unsafe impl<D: QueryData> WorldQuery for NopWorldQuery<D> {
type Item<'w> = ();
type Fetch<'w> = ();
type State = D::State;
fn shrink<'wlong: 'wshort, 'wshort>(_: ()) {}
#[inline(always)]
unsafe fn init_fetch(
_world: UnsafeWorldCell,
_state: &D::State,
_last_run: Tick,
_this_run: Tick,
) {
}
const IS_DENSE: bool = D::IS_DENSE;
#[inline(always)]
unsafe fn set_archetype(
_fetch: &mut (),
_state: &D::State,
_archetype: &Archetype,
_tables: &Table,
) {
}
#[inline(always)]
unsafe fn set_table<'w>(_fetch: &mut (), _state: &D::State, _table: &Table) {}
#[inline(always)]
unsafe fn fetch<'w>(
_fetch: &mut Self::Fetch<'w>,
_entity: Entity,
_table_row: TableRow,
) -> Self::Item<'w> {
}
fn update_component_access(_state: &D::State, _access: &mut FilteredAccess<ComponentId>) {}
fn init_state(world: &mut World) -> Self::State {
D::init_state(world)
}
fn get_state(world: &World) -> Option<Self::State> {
D::get_state(world)
}
fn matches_component_set(
state: &Self::State,
set_contains_id: &impl Fn(ComponentId) -> bool,
) -> bool {
D::matches_component_set(state, set_contains_id)
}
}
/// SAFETY: `Self::ReadOnly` is `Self`
unsafe impl<D: QueryData> QueryData for NopWorldQuery<D> {
type ReadOnly = Self;
}
/// SAFETY: `NopFetch` never accesses any data
unsafe impl<D: QueryData> ReadOnlyQueryData for NopWorldQuery<D> {}
/// SAFETY:
/// `update_component_access` and `update_archetype_component_access` do nothing.
/// This is sound because `fetch` does not access components.
unsafe impl<T: ?Sized> WorldQuery for PhantomData<T> {
type Item<'a> = ();
type Fetch<'a> = ();
type State = ();
fn shrink<'wlong: 'wshort, 'wshort>(_item: Self::Item<'wlong>) -> Self::Item<'wshort> {}
unsafe fn init_fetch<'w>(
_world: UnsafeWorldCell<'w>,
_state: &Self::State,
_last_run: Tick,
_this_run: Tick,
) -> Self::Fetch<'w> {
}
// `PhantomData` does not match any components, so all components it matches
// are stored in a Table (vacuous truth).
const IS_DENSE: bool = true;
unsafe fn set_archetype<'w>(
_fetch: &mut Self::Fetch<'w>,
_state: &Self::State,
_archetype: &'w Archetype,
_table: &'w Table,
) {
}
unsafe fn set_table<'w>(_fetch: &mut Self::Fetch<'w>, _state: &Self::State, _table: &'w Table) {
}
unsafe fn fetch<'w>(
_fetch: &mut Self::Fetch<'w>,
_entity: Entity,
_table_row: TableRow,
) -> Self::Item<'w> {
}
fn update_component_access(_state: &Self::State, _access: &mut FilteredAccess<ComponentId>) {}
fn init_state(_world: &mut World) -> Self::State {}
fn get_state(_world: &World) -> Option<Self::State> {
Some(())
}
fn matches_component_set(
_state: &Self::State,
_set_contains_id: &impl Fn(ComponentId) -> bool,
) -> bool {
true
}
}
/// SAFETY: `Self::ReadOnly` is `Self`
unsafe impl<T: ?Sized> QueryData for PhantomData<T> {
type ReadOnly = Self;
}
/// SAFETY: `PhantomData` never accesses any world data.
unsafe impl<T: ?Sized> ReadOnlyQueryData for PhantomData<T> {}
#[cfg(test)]
mod tests {
use bevy_ecs_macros::QueryData;
use super::*;
use crate::{
self as bevy_ecs,
system::{assert_is_system, Query},
};
#[derive(Component)]
pub struct A;
#[derive(Component)]
pub struct B;
// Tests that each variant of struct can be used as a `WorldQuery`.
#[test]
fn world_query_struct_variants() {
#[derive(QueryData)]
pub struct NamedQuery {
id: Entity,
a: &'static A,
}
#[derive(QueryData)]
pub struct TupleQuery(&'static A, &'static B);
#[derive(QueryData)]
pub struct UnitQuery;
fn my_system(_: Query<(NamedQuery, TupleQuery, UnitQuery)>) {}
assert_is_system(my_system);
}
// Compile test for https://github.com/bevyengine/bevy/pull/8030.
#[test]
fn world_query_phantom_data() {
#[derive(QueryData)]
pub struct IgnoredQuery<Marker> {
id: Entity,
_marker: PhantomData<Marker>,
}
fn ignored_system(_: Query<IgnoredQuery<()>>) {}
assert_is_system(ignored_system);
}
// Ensures that each field of a `WorldQuery` struct's read-only variant
// has the same visibility as its corresponding mutable field.
#[test]
fn read_only_field_visibility() {
mod private {
use super::*;
#[derive(QueryData)]
#[query_data(mutable)]
pub struct D {
pub a: &'static mut A,
}
}
let _ = private::DReadOnly { a: &A };
fn my_system(query: Query<private::D>) {
for q in &query {
let _ = &q.a;
}
}
assert_is_system(my_system);
}
// Ensures that metadata types generated by the WorldQuery macro
// do not conflict with user-defined types.
// Regression test for https://github.com/bevyengine/bevy/issues/8010.
#[test]
fn world_query_metadata_collision() {
// The metadata types generated would be named `ClientState` and `ClientFetch`,
// but they should rename themselves to avoid conflicts.
#[derive(QueryData)]
pub struct Client<S: ClientState> {
pub state: &'static S,
pub fetch: &'static ClientFetch,
}
pub trait ClientState: Component {}
#[derive(Component)]
pub struct ClientFetch;
#[derive(Component)]
pub struct C;
impl ClientState for C {}
fn client_system(_: Query<Client<C>>) {}
assert_is_system(client_system);
}
}