bevy/crates/bevy_ecs/src/query/fetch.rs
James Liu 530be10e72 Newtype ArchetypeRow and TableRow (#4878)
# Objective
Prevent future unsoundness that was seen in #6623.

## Solution
Newtype both indexes in `Archetype` and `Table` as `ArchetypeRow` and `TableRow`. This avoids weird numerical manipulation on the indices, and can be stored and treated opaquely. Also enforces the source and destination of where these indices at a type level.

---

## Changelog
Changed: `Archetype` indices and `Table` rows have been newtyped as `ArchetypeRow` and `TableRow`.
2022-12-06 01:38:21 +00:00

1476 lines
50 KiB
Rust

use crate::{
archetype::{Archetype, ArchetypeComponentId},
change_detection::Ticks,
component::{Component, ComponentId, ComponentStorage, ComponentTicks, StorageType, Tick},
entity::Entity,
query::{Access, DebugCheckedUnwrap, FilteredAccess},
storage::{ComponentSparseSet, Table, TableRow},
world::{Mut, World},
};
use bevy_ecs_macros::all_tuples;
pub use bevy_ecs_macros::WorldQuery;
use bevy_ptr::{ThinSlicePtr, UnsafeCellDeref};
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).
/// - **`WorldQuery` tuples.**
/// If every element of a tuple implements `WorldQuery`, then the tuple itself also implements the same trait.
/// This enables a single `Query` to access multiple components and filter over multiple conditions.
/// 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.
/// - **Component filters.**
/// [`With`] and [`Without`] filters can be applied to check if the queried entity contains or not a particular component.
/// - **Change detection filters.**
/// [`Added`] and [`Changed`] filters can be applied to detect component changes to an entity.
/// - **Filter disjunction operator.**
/// By default, tuples compose query filters in such a way that all conditions must be satisfied to generate a query item for a given entity.
/// Wrapping a tuple inside an [`Or`] operator will relax the requirement to just one condition.
/// - **[`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`.
/// - **[`ChangeTrackers`].**
/// 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.
///
/// Implementing the trait manually can allow for a fundamentally new type of behaviour.
///
/// # Trait derivation
///
/// Query design can be easily structured by deriving `WorldQuery` for custom types.
/// Despite the added complexity, this approach has several advantages over using `WorldQuery` 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 if each field either
///
/// * also implements `WorldQuery`, or
/// * is marked with `#[world_query(ignore)]`. Fields decorated with this attribute
/// must implement [`Default`] and will be initialized to the default value as defined
/// by the trait.
///
/// The derive macro only supports regular structs (structs with named fields).
///
/// ```
/// # use bevy_ecs::prelude::*;
/// use bevy_ecs::query::WorldQuery;
/// #
/// # #[derive(Component)]
/// # struct ComponentA;
/// # #[derive(Component)]
/// # struct ComponentB;
///
/// #[derive(WorldQuery)]
/// 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 three or six 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|
/// |:---:|:---:|---|
/// |`XState`|---|Used as the [`State`] type for `X` and `XReadOnly`|
/// |`XItem`|---|The type of the query item for `X`|
/// |`XFetch`|---|Used as the [`Fetch`] type for `X`|
/// |`XReadOnlyItem`|✓|The type of the query item for `XReadOnly`|
/// |`XReadOnlyFetch`|✓|Used as the [`Fetch`] type for `XReadOnly`|
/// |`XReadOnly`|✓|[`ReadOnly`] variant of `X`|
///
/// ## Adding mutable references
///
/// Simply adding mutable references to a derived `WorldQuery` will result in a compilation error:
///
/// ```compile_fail
/// # use bevy_ecs::prelude::*;
/// # use bevy_ecs::query::WorldQuery;
/// #
/// # #[derive(Component)]
/// # struct ComponentA;
/// #
/// #[derive(WorldQuery)]
/// struct CustomQuery {
/// component_a: &'static mut ComponentA,
/// }
/// ```
///
/// To grant mutable access to components, the struct must be marked with the `#[world_query(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::WorldQuery;
/// #
/// # #[derive(Component)]
/// # struct ComponentA;
/// #
/// #[derive(WorldQuery)]
/// #[world_query(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::WorldQuery;
/// #
/// #[derive(Component)]
/// struct Health(f32);
///
/// #[derive(Component)]
/// struct Buff(f32);
///
/// #[derive(WorldQuery)]
/// #[world_query(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 `WorldQuery` derive macro does not automatically implement the traits of the struct to the query item types.
/// Something similar can be done by using the `#[world_query(derive(...))]` attribute.
/// This will apply the listed derivable traits to the query item structs.
///
/// ```
/// # use bevy_ecs::prelude::*;
/// # use bevy_ecs::query::WorldQuery;
/// #
/// # #[derive(Component, Debug)]
/// # struct ComponentA;
/// #
/// #[derive(WorldQuery)]
/// #[world_query(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 `WorldQuery` as a field of another one.
/// This means that a `WorldQuery` can also be used as a subquery, potentially in multiple places.
///
/// ```
/// # use bevy_ecs::prelude::*;
/// # use bevy_ecs::query::WorldQuery;
/// #
/// # #[derive(Component)]
/// # struct ComponentA;
/// # #[derive(Component)]
/// # struct ComponentB;
/// # #[derive(Component)]
/// # struct ComponentC;
/// #
/// #[derive(WorldQuery)]
/// struct SubQuery {
/// component_a: &'static ComponentA,
/// component_b: &'static ComponentB,
/// }
///
/// #[derive(WorldQuery)]
/// struct MyQuery {
/// subquery: SubQuery,
/// component_c: &'static ComponentC,
/// }
/// ```
///
/// ## Filters
///
/// Since the query filter type parameter is `WorldQuery`, it is also possible to use this macro to create filters.
///
/// ```
/// # use bevy_ecs::prelude::*;
/// # use bevy_ecs::{query::WorldQuery, component::Component};
/// #
/// # #[derive(Component)]
/// # struct ComponentA;
/// # #[derive(Component)]
/// # struct ComponentB;
/// # #[derive(Component)]
/// # struct ComponentC;
/// # #[derive(Component)]
/// # struct ComponentD;
/// # #[derive(Component)]
/// # struct ComponentE;
/// #
/// #[derive(WorldQuery)]
/// struct MyFilter<T: Component, P: Component> {
/// // Field names are not relevant, since they are never manually accessed.
/// with_a: With<ComponentA>,
/// or_filter: Or<(With<ComponentC>, Added<ComponentB>)>,
/// generic_tuple: (With<T>, Without<P>),
/// }
///
/// fn my_system(query: Query<Entity, MyFilter<ComponentD, ComponentE>>) {
/// // ...
/// }
/// # 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`
///
/// Implementor must ensure that
/// [`update_component_access`] and [`update_archetype_component_access`]
/// exactly reflects the results of the following methods:
///
/// - [`matches_component_set`]
/// - [`fetch`]
///
/// [`Added`]: crate::query::Added
/// [`fetch`]: Self::fetch
/// [`Changed`]: crate::query::Changed
/// [`Fetch`]: crate::query::WorldQuery::Fetch
/// [`matches_component_set`]: Self::matches_component_set
/// [`Or`]: crate::query::Or
/// [`Query`]: crate::system::Query
/// [`ReadOnly`]: Self::ReadOnly
/// [`State`]: Self::State
/// [`update_archetype_component_access`]: Self::update_archetype_component_access
/// [`update_component_access`]: Self::update_component_access
/// [`With`]: crate::query::With
/// [`Without`]: crate::query::Without
pub unsafe trait WorldQuery {
/// The item returned by this [`WorldQuery`]
type Item<'a>;
/// Per archetype/table state used by this [`WorldQuery`] to fetch [`Self::Item`](crate::query::WorldQuery::Item)
type Fetch<'a>;
/// The read-only variant of this [`WorldQuery`], which satisfies the [`ReadOnlyWorldQuery`] trait.
type ReadOnly: ReadOnlyWorldQuery<State = Self::State>;
/// State used to construct a [`Self::Fetch`](crate::query::WorldQuery::Fetch). This will be cached inside [`QueryState`](crate::query::QueryState),
/// so it is best to move as much data / computation here as possible to reduce the cost of
/// constructing [`Self::Fetch`](crate::query::WorldQuery::Fetch).
type State: Send + Sync + Sized;
/// This function manually implements subtyping for the query items.
fn shrink<'wlong: 'wshort, 'wshort>(item: Self::Item<'wlong>) -> Self::Item<'wshort>;
/// Creates a new instance of this fetch.
///
/// # Safety
///
/// `state` must have been initialized (via [`WorldQuery::init_state`]) using the same `world` passed
/// in to this function.
unsafe fn init_fetch<'w>(
world: &'w World,
state: &Self::State,
last_change_tick: u32,
change_tick: u32,
) -> Self::Fetch<'w>;
/// While this function can be called for any query, it is always safe to call if `Self: ReadOnlyWorldQuery` holds.
///
/// # Safety
/// While calling this method on its own cannot cause UB it is marked `unsafe` as the caller must ensure
/// that the returned value is not used in any way that would cause two `QueryItem<Self>` for the same
/// `archetype_row` or `table_row` to be alive at the same time.
unsafe fn clone_fetch<'w>(fetch: &Self::Fetch<'w>) -> Self::Fetch<'w>;
/// Returns true if (and only if) every table of every archetype matched by this fetch contains
/// all of the matched components. This is used to select a more efficient "table iterator"
/// for "dense" queries. If this returns true, [`WorldQuery::set_table`] must be used before
/// [`WorldQuery::fetch`] can be called for iterators. If this returns false,
/// [`WorldQuery::set_archetype`] must be used before [`WorldQuery::fetch`] can be called for
/// iterators.
const IS_DENSE: bool;
/// Returns true if (and only if) this Fetch relies strictly on archetypes to limit which
/// components are accessed by the Query.
///
/// This enables optimizations for [`crate::query::QueryIter`] that rely on knowing exactly how
/// many elements are being iterated (such as `Iterator::collect()`).
const IS_ARCHETYPAL: bool;
/// Adjusts internal state to account for the next [`Archetype`]. This will always be called on
/// archetypes that match this [`WorldQuery`].
///
/// # Safety
///
/// `archetype` and `tables` must be from the [`World`] [`WorldQuery::init_state`] was called on. `state` must
/// be the [`Self::State`] this was initialized with.
unsafe fn set_archetype<'w>(
fetch: &mut Self::Fetch<'w>,
state: &Self::State,
archetype: &'w Archetype,
table: &'w Table,
);
/// Adjusts internal state to account for the next [`Table`]. This will always be called on tables
/// that match this [`WorldQuery`].
///
/// # Safety
///
/// `table` must be from the [`World`] [`WorldQuery::init_state`] was called on. `state` must be the
/// [`Self::State`] this was initialized with.
unsafe fn set_table<'w>(fetch: &mut Self::Fetch<'w>, state: &Self::State, table: &'w Table);
/// Fetch [`Self::Item`](`WorldQuery::Item`) for either the given `entity` in the current [`Table`],
/// or for the given `entity` in the current [`Archetype`]. This must always be called after
/// [`WorldQuery::set_table`] with a `table_row` in the range of the current [`Table`] or after
/// [`WorldQuery::set_archetype`] with a `entity` in the current archetype.
///
/// # Safety
///
/// Must always be called _after_ [`WorldQuery::set_table`] or [`WorldQuery::set_archetype`]. `entity` and
/// `table_row` must be in the range of the current table and archetype.
unsafe fn fetch<'w>(
fetch: &mut Self::Fetch<'w>,
entity: Entity,
table_row: TableRow,
) -> Self::Item<'w>;
/// # Safety
///
/// Must always be called _after_ [`WorldQuery::set_table`] or [`WorldQuery::set_archetype`]. `entity` and
/// `table_row` must be in the range of the current table and archetype.
#[allow(unused_variables)]
#[inline(always)]
unsafe fn filter_fetch(
fetch: &mut Self::Fetch<'_>,
entity: Entity,
table_row: TableRow,
) -> bool {
true
}
// This does not have a default body of `{}` because 99% of cases need to add accesses
// and forgetting to do so would be unsound.
fn update_component_access(state: &Self::State, access: &mut FilteredAccess<ComponentId>);
// This does not have a default body of `{}` becaues 99% of cases need to add accesses
// and forgetting to do so would be unsound.
fn update_archetype_component_access(
state: &Self::State,
archetype: &Archetype,
access: &mut Access<ArchetypeComponentId>,
);
fn init_state(world: &mut World) -> Self::State;
fn matches_component_set(
state: &Self::State,
set_contains_id: &impl Fn(ComponentId) -> bool,
) -> bool;
}
/// A world query that is read only.
///
/// # Safety
///
/// This must only be implemented for read-only [`WorldQuery`]'s.
pub unsafe trait ReadOnlyWorldQuery: WorldQuery<ReadOnly = Self> {}
/// The `Fetch` of a [`WorldQuery`], which is used to store state for each archetype/table.
pub type QueryFetch<'w, Q> = <Q as WorldQuery>::Fetch<'w>;
/// The item type returned when a [`WorldQuery`] is iterated over
pub type QueryItem<'w, Q> = <Q as WorldQuery>::Item<'w>;
/// The read-only `Fetch` of a [`WorldQuery`], which is used to store state for each archetype/table.
pub type ROQueryFetch<'w, Q> = QueryFetch<'w, <Q as WorldQuery>::ReadOnly>;
/// The read-only variant of the item type returned when a [`WorldQuery`] is iterated over immutably
pub type ROQueryItem<'w, Q> = QueryItem<'w, <Q as WorldQuery>::ReadOnly>;
/// SAFETY: no component or archetype access
unsafe impl WorldQuery for Entity {
type Fetch<'w> = ();
type Item<'w> = Entity;
type ReadOnly = Self;
type State = ();
fn shrink<'wlong: 'wshort, 'wshort>(item: Self::Item<'wlong>) -> Self::Item<'wshort> {
item
}
const IS_DENSE: bool = true;
const IS_ARCHETYPAL: bool = true;
unsafe fn init_fetch<'w>(
_world: &'w World,
_state: &Self::State,
_last_change_tick: u32,
_change_tick: u32,
) -> Self::Fetch<'w> {
}
unsafe fn clone_fetch<'w>(_fetch: &Self::Fetch<'w>) -> Self::Fetch<'w> {}
#[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 update_archetype_component_access(
_state: &Self::State,
_archetype: &Archetype,
_access: &mut Access<ArchetypeComponentId>,
) {
}
fn init_state(_world: &mut World) {}
fn matches_component_set(
_state: &Self::State,
_set_contains_id: &impl Fn(ComponentId) -> bool,
) -> bool {
true
}
}
/// SAFETY: access is read only
unsafe impl ReadOnlyWorldQuery for Entity {}
#[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>,
}
/// SAFETY: `Self` is the same as `Self::ReadOnly`
unsafe impl<T: Component> WorldQuery for &T {
type Fetch<'w> = ReadFetch<'w, T>;
type Item<'w> = &'w T;
type ReadOnly = Self;
type State = ComponentId;
fn shrink<'wlong: 'wshort, 'wshort>(item: &'wlong T) -> &'wshort T {
item
}
const IS_DENSE: bool = {
match T::Storage::STORAGE_TYPE {
StorageType::Table => true,
StorageType::SparseSet => false,
}
};
const IS_ARCHETYPAL: bool = true;
unsafe fn init_fetch<'w>(
world: &'w World,
&component_id: &ComponentId,
_last_change_tick: u32,
_change_tick: u32,
) -> ReadFetch<'w, T> {
ReadFetch {
table_components: None,
sparse_set: (T::Storage::STORAGE_TYPE == StorageType::SparseSet).then(|| {
world
.storages()
.sparse_sets
.get(component_id)
.debug_checked_unwrap()
}),
}
}
unsafe fn clone_fetch<'w>(fetch: &Self::Fetch<'w>) -> Self::Fetch<'w> {
ReadFetch {
table_components: fetch.table_components,
sparse_set: fetch.sparse_set,
}
}
#[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.index())
.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 update_archetype_component_access(
&component_id: &ComponentId,
archetype: &Archetype,
access: &mut Access<ArchetypeComponentId>,
) {
if let Some(archetype_component_id) = archetype.get_archetype_component_id(component_id) {
access.add_read(archetype_component_id);
}
}
fn init_state(world: &mut World) -> ComponentId {
world.init_component::<T>()
}
fn matches_component_set(
&state: &ComponentId,
set_contains_id: &impl Fn(ComponentId) -> bool,
) -> bool {
set_contains_id(state)
}
}
/// SAFETY: access is read only
unsafe impl<T: Component> ReadOnlyWorldQuery for &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_change_tick: u32,
change_tick: u32,
}
/// SAFETY: access of `&T` is a subset of `&mut T`
unsafe impl<'__w, T: Component> WorldQuery for &'__w mut T {
type Fetch<'w> = WriteFetch<'w, T>;
type Item<'w> = Mut<'w, T>;
type ReadOnly = &'__w T;
type State = ComponentId;
fn shrink<'wlong: 'wshort, 'wshort>(item: Mut<'wlong, T>) -> Mut<'wshort, T> {
item
}
const IS_DENSE: bool = {
match T::Storage::STORAGE_TYPE {
StorageType::Table => true,
StorageType::SparseSet => false,
}
};
const IS_ARCHETYPAL: bool = true;
unsafe fn init_fetch<'w>(
world: &'w World,
&component_id: &ComponentId,
last_change_tick: u32,
change_tick: u32,
) -> WriteFetch<'w, T> {
WriteFetch {
table_data: None,
sparse_set: (T::Storage::STORAGE_TYPE == StorageType::SparseSet).then(|| {
world
.storages()
.sparse_sets
.get(component_id)
.debug_checked_unwrap()
}),
last_change_tick,
change_tick,
}
}
unsafe fn clone_fetch<'w>(fetch: &Self::Fetch<'w>) -> Self::Fetch<'w> {
WriteFetch {
table_data: fetch.table_data,
sparse_set: fetch.sparse_set,
last_change_tick: fetch.last_change_tick,
change_tick: fetch.change_tick,
}
}
#[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.index()).deref_mut(),
ticks: Ticks {
added: added_ticks.get(table_row.index()).deref_mut(),
changed: changed_ticks.get(table_row.index()).deref_mut(),
change_tick: fetch.change_tick,
last_change_tick: fetch.last_change_tick,
},
}
}
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: Ticks::from_tick_cells(ticks, fetch.change_tick, fetch.last_change_tick),
}
}
}
}
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 update_archetype_component_access(
&component_id: &ComponentId,
archetype: &Archetype,
access: &mut Access<ArchetypeComponentId>,
) {
if let Some(archetype_component_id) = archetype.get_archetype_component_id(component_id) {
access.add_write(archetype_component_id);
}
}
fn init_state(world: &mut World) -> ComponentId {
world.init_component::<T>()
}
fn matches_component_set(
&state: &ComponentId,
set_contains_id: &impl Fn(ComponentId) -> bool,
) -> bool {
set_contains_id(state)
}
}
#[doc(hidden)]
pub struct OptionFetch<'w, T: WorldQuery> {
fetch: T::Fetch<'w>,
matches: bool,
}
// SAFETY: defers to soundness of `T: WorldQuery` impl
unsafe impl<T: WorldQuery> WorldQuery for Option<T> {
type Fetch<'w> = OptionFetch<'w, T>;
type Item<'w> = Option<T::Item<'w>>;
type ReadOnly = Option<T::ReadOnly>;
type State = T::State;
fn shrink<'wlong: 'wshort, 'wshort>(item: Self::Item<'wlong>) -> Self::Item<'wshort> {
item.map(T::shrink)
}
const IS_DENSE: bool = T::IS_DENSE;
const IS_ARCHETYPAL: bool = T::IS_ARCHETYPAL;
unsafe fn init_fetch<'w>(
world: &'w World,
state: &T::State,
last_change_tick: u32,
change_tick: u32,
) -> OptionFetch<'w, T> {
OptionFetch {
fetch: T::init_fetch(world, state, last_change_tick, change_tick),
matches: false,
}
}
unsafe fn clone_fetch<'w>(fetch: &Self::Fetch<'w>) -> Self::Fetch<'w> {
OptionFetch {
fetch: T::clone_fetch(&fetch.fetch),
matches: fetch.matches,
}
}
#[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>) {
// We don't want to add the `with`/`without` of `T` as `Option<T>` will match things regardless of
// `T`'s filters. for example `Query<(Option<&U>, &mut V)>` will match every entity with a `V` component
// regardless of whether it has a `U` component. If we dont do this the query will not conflict with
// `Query<&mut V, Without<U>>` which would be unsound.
let mut intermediate = access.clone();
T::update_component_access(state, &mut intermediate);
access.extend_access(&intermediate);
}
fn update_archetype_component_access(
state: &T::State,
archetype: &Archetype,
access: &mut Access<ArchetypeComponentId>,
) {
if T::matches_component_set(state, &|id| archetype.contains(id)) {
T::update_archetype_component_access(state, archetype, access);
}
}
fn init_state(world: &mut World) -> T::State {
T::init_state(world)
}
fn matches_component_set(
_state: &T::State,
_set_contains_id: &impl Fn(ComponentId) -> bool,
) -> bool {
true
}
}
/// SAFETY: [`OptionFetch`] is read only because `T` is read only
unsafe impl<T: ReadOnlyWorldQuery> ReadOnlyWorldQuery for Option<T> {}
/// [`WorldQuery`] that tracks changes and additions for component `T`.
///
/// Wraps a [`Component`] to track whether the component changed for the corresponding entities in
/// a query since the last time the system that includes these queries ran.
///
/// If you only care about entities that changed or that got added use the
/// [`Changed`](crate::query::Changed) and [`Added`](crate::query::Added) filters instead.
///
/// # Examples
///
/// ```
/// # use bevy_ecs::component::Component;
/// # use bevy_ecs::query::ChangeTrackers;
/// # use bevy_ecs::system::IntoSystem;
/// # use bevy_ecs::system::Query;
/// #
/// # #[derive(Component, Debug)]
/// # struct Name {};
/// # #[derive(Component)]
/// # struct Transform {};
/// #
/// fn print_moving_objects_system(query: Query<(&Name, ChangeTrackers<Transform>)>) {
/// for (name, tracker) in &query {
/// if tracker.is_changed() {
/// println!("Entity moved: {:?}", name);
/// } else {
/// println!("Entity stood still: {:?}", name);
/// }
/// }
/// }
/// # bevy_ecs::system::assert_is_system(print_moving_objects_system);
/// ```
pub struct ChangeTrackers<T: Component> {
pub(crate) component_ticks: ComponentTicks,
pub(crate) last_change_tick: u32,
pub(crate) change_tick: u32,
marker: PhantomData<T>,
}
impl<T: Component> Clone for ChangeTrackers<T> {
fn clone(&self) -> Self {
Self {
component_ticks: self.component_ticks,
last_change_tick: self.last_change_tick,
change_tick: self.change_tick,
marker: PhantomData,
}
}
}
impl<T: Component> Copy for ChangeTrackers<T> {}
impl<T: Component> std::fmt::Debug for ChangeTrackers<T> {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
f.debug_struct("ChangeTrackers")
.field("component_ticks", &self.component_ticks)
.field("last_change_tick", &self.last_change_tick)
.field("change_tick", &self.change_tick)
.finish()
}
}
impl<T: Component> ChangeTrackers<T> {
/// Returns true if this component has been added since the last execution of this system.
pub fn is_added(&self) -> bool {
self.component_ticks
.is_added(self.last_change_tick, self.change_tick)
}
/// Returns true if this component has been changed since the last execution of this system.
pub fn is_changed(&self) -> bool {
self.component_ticks
.is_changed(self.last_change_tick, self.change_tick)
}
}
#[doc(hidden)]
pub struct ChangeTrackersFetch<'w, T> {
// T::Storage = TableStorage
table_added: Option<ThinSlicePtr<'w, UnsafeCell<Tick>>>,
table_changed: Option<ThinSlicePtr<'w, UnsafeCell<Tick>>>,
// T::Storage = SparseStorage
sparse_set: Option<&'w ComponentSparseSet>,
marker: PhantomData<T>,
last_change_tick: u32,
change_tick: u32,
}
// SAFETY: `ROQueryFetch<Self>` is the same as `QueryFetch<Self>`
unsafe impl<T: Component> WorldQuery for ChangeTrackers<T> {
type Fetch<'w> = ChangeTrackersFetch<'w, T>;
type Item<'w> = ChangeTrackers<T>;
type ReadOnly = Self;
type State = ComponentId;
fn shrink<'wlong: 'wshort, 'wshort>(item: Self::Item<'wlong>) -> Self::Item<'wshort> {
item
}
const IS_DENSE: bool = {
match T::Storage::STORAGE_TYPE {
StorageType::Table => true,
StorageType::SparseSet => false,
}
};
const IS_ARCHETYPAL: bool = true;
unsafe fn init_fetch<'w>(
world: &'w World,
&component_id: &ComponentId,
last_change_tick: u32,
change_tick: u32,
) -> ChangeTrackersFetch<'w, T> {
ChangeTrackersFetch {
table_added: None,
table_changed: None,
sparse_set: (T::Storage::STORAGE_TYPE == StorageType::SparseSet).then(|| {
world
.storages()
.sparse_sets
.get(component_id)
.debug_checked_unwrap()
}),
marker: PhantomData,
last_change_tick,
change_tick,
}
}
unsafe fn clone_fetch<'w>(fetch: &Self::Fetch<'w>) -> Self::Fetch<'w> {
ChangeTrackersFetch {
table_added: fetch.table_added,
table_changed: fetch.table_changed,
sparse_set: fetch.sparse_set,
marker: fetch.marker,
last_change_tick: fetch.last_change_tick,
change_tick: fetch.change_tick,
}
}
#[inline]
unsafe fn set_archetype<'w>(
fetch: &mut ChangeTrackersFetch<'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 ChangeTrackersFetch<'w, T>,
&id: &ComponentId,
table: &'w Table,
) {
let column = table.get_column(id).debug_checked_unwrap();
fetch.table_added = Some(column.get_added_ticks_slice().into());
fetch.table_changed = Some(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 => ChangeTrackers {
component_ticks: {
ComponentTicks {
added: fetch
.table_added
.debug_checked_unwrap()
.get(table_row.index())
.read(),
changed: fetch
.table_changed
.debug_checked_unwrap()
.get(table_row.index())
.read(),
}
},
marker: PhantomData,
last_change_tick: fetch.last_change_tick,
change_tick: fetch.change_tick,
},
StorageType::SparseSet => ChangeTrackers {
component_ticks: fetch
.sparse_set
.debug_checked_unwrap()
.get_ticks(entity)
.debug_checked_unwrap(),
marker: PhantomData,
last_change_tick: fetch.last_change_tick,
change_tick: fetch.change_tick,
},
}
}
fn update_component_access(&id: &ComponentId, access: &mut FilteredAccess<ComponentId>) {
assert!(
!access.access().has_write(id),
"ChangeTrackers<{}> conflicts with a previous access in this query. Shared access cannot coincide with exclusive access.",
std::any::type_name::<T>()
);
access.add_read(id);
}
fn update_archetype_component_access(
&id: &ComponentId,
archetype: &Archetype,
access: &mut Access<ArchetypeComponentId>,
) {
if let Some(archetype_component_id) = archetype.get_archetype_component_id(id) {
access.add_read(archetype_component_id);
}
}
fn init_state(world: &mut World) -> ComponentId {
world.init_component::<T>()
}
fn matches_component_set(
&id: &ComponentId,
set_contains_id: &impl Fn(ComponentId) -> bool,
) -> bool {
set_contains_id(id)
}
}
/// SAFETY: access is read only
unsafe impl<T: Component> ReadOnlyWorldQuery for ChangeTrackers<T> {}
macro_rules! impl_tuple_fetch {
($(($name: ident, $state: ident)),*) => {
#[allow(non_snake_case)]
#[allow(clippy::unused_unit)]
// SAFETY: defers to soundness `$name: WorldQuery` impl
unsafe impl<$($name: WorldQuery),*> WorldQuery for ($($name,)*) {
type Fetch<'w> = ($($name::Fetch<'w>,)*);
type Item<'w> = ($($name::Item<'w>,)*);
type ReadOnly = ($($name::ReadOnly,)*);
type State = ($($name::State,)*);
fn shrink<'wlong: 'wshort, 'wshort>(item: Self::Item<'wlong>) -> Self::Item<'wshort> {
let ($($name,)*) = item;
($(
$name::shrink($name),
)*)
}
#[allow(clippy::unused_unit)]
unsafe fn init_fetch<'w>(_world: &'w World, state: &Self::State, _last_change_tick: u32, _change_tick: u32) -> Self::Fetch<'w> {
let ($($name,)*) = state;
($($name::init_fetch(_world, $name, _last_change_tick, _change_tick),)*)
}
unsafe fn clone_fetch<'w>(
fetch: &Self::Fetch<'w>,
) -> Self::Fetch<'w> {
let ($($name,)*) = &fetch;
($($name::clone_fetch($name),)*)
}
const IS_DENSE: bool = true $(&& $name::IS_DENSE)*;
const IS_ARCHETYPAL: bool = true $(&& $name::IS_ARCHETYPAL)*;
#[inline]
unsafe fn set_archetype<'w>(
_fetch: &mut Self::Fetch<'w>,
_state: &Self::State,
_archetype: &'w Archetype,
_table: &'w Table
) {
let ($($name,)*) = _fetch;
let ($($state,)*) = _state;
$($name::set_archetype($name, $state, _archetype, _table);)*
}
#[inline]
unsafe fn set_table<'w>(_fetch: &mut Self::Fetch<'w>, _state: &Self::State, _table: &'w Table) {
let ($($name,)*) = _fetch;
let ($($state,)*) = _state;
$($name::set_table($name, $state, _table);)*
}
#[inline(always)]
#[allow(clippy::unused_unit)]
unsafe fn fetch<'w>(
_fetch: &mut Self::Fetch<'w>,
_entity: Entity,
_table_row: TableRow
) -> Self::Item<'w> {
let ($($name,)*) = _fetch;
($($name::fetch($name, _entity, _table_row),)*)
}
#[inline(always)]
unsafe fn filter_fetch<'w>(
_fetch: &mut Self::Fetch<'w>,
_entity: Entity,
_table_row: TableRow
) -> bool {
let ($($name,)*) = _fetch;
true $(&& $name::filter_fetch($name, _entity, _table_row))*
}
fn update_component_access(state: &Self::State, _access: &mut FilteredAccess<ComponentId>) {
let ($($name,)*) = state;
$($name::update_component_access($name, _access);)*
}
fn update_archetype_component_access(state: &Self::State, _archetype: &Archetype, _access: &mut Access<ArchetypeComponentId>) {
let ($($name,)*) = state;
$($name::update_archetype_component_access($name, _archetype, _access);)*
}
fn init_state(_world: &mut World) -> Self::State {
($($name::init_state(_world),)*)
}
fn matches_component_set(state: &Self::State, _set_contains_id: &impl Fn(ComponentId) -> bool) -> bool {
let ($($name,)*) = state;
true $(&& $name::matches_component_set($name, _set_contains_id))*
}
}
/// SAFETY: each item in the tuple is read only
unsafe impl<$($name: ReadOnlyWorldQuery),*> ReadOnlyWorldQuery for ($($name,)*) {}
};
}
/// 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_anytuple_fetch {
($(($name: ident, $state: ident)),*) => {
#[allow(non_snake_case)]
#[allow(clippy::unused_unit)]
// SAFETY: defers to soundness of `$name: WorldQuery` impl
unsafe impl<$($name: WorldQuery),*> WorldQuery for AnyOf<($($name,)*)> {
type Fetch<'w> = ($(($name::Fetch<'w>, bool),)*);
type Item<'w> = ($(Option<$name::Item<'w>>,)*);
type ReadOnly = AnyOf<($($name::ReadOnly,)*)>;
type State = ($($name::State,)*);
fn shrink<'wlong: 'wshort, 'wshort>(item: Self::Item<'wlong>) -> Self::Item<'wshort> {
let ($($name,)*) = item;
($(
$name.map($name::shrink),
)*)
}
#[allow(clippy::unused_unit)]
unsafe fn init_fetch<'w>(_world: &'w World, state: &Self::State, _last_change_tick: u32, _change_tick: u32) -> Self::Fetch<'w> {
let ($($name,)*) = state;
($(($name::init_fetch(_world, $name, _last_change_tick, _change_tick), false),)*)
}
unsafe fn clone_fetch<'w>(
fetch: &Self::Fetch<'w>,
) -> Self::Fetch<'w> {
let ($($name,)*) = &fetch;
($(($name::clone_fetch(& $name.0), $name.1),)*)
}
const IS_DENSE: bool = true $(&& $name::IS_DENSE)*;
const IS_ARCHETYPAL: bool = true $(&& $name::IS_ARCHETYPAL)*;
#[inline]
unsafe fn set_archetype<'w>(
_fetch: &mut Self::Fetch<'w>,
_state: &Self::State,
_archetype: &'w Archetype,
_table: &'w Table
) {
let ($($name,)*) = _fetch;
let ($($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 $name.0, _entity, _table_row)),
)*)
}
fn update_component_access(state: &Self::State, _access: &mut FilteredAccess<ComponentId>) {
let ($($name,)*) = state;
// We do not unconditionally add `$name`'s `with`/`without` accesses to `_access`
// as this would be unsound. For example the following two queries should conflict:
// - Query<(AnyOf<(&A, ())>, &mut B)>
// - Query<&mut B, Without<A>>
//
// If we were to unconditionally add `$name`'s `with`/`without` accesses then `AnyOf<(&A, ())>`
// would have a `With<A>` access which is incorrect as this `WorldQuery` will match entities that
// do not have the `A` component. This is the same logic as the `Or<...>: WorldQuery` impl.
//
// The correct thing to do here is to only add a `with`/`without` access to `_access` if all
// `$name` params have that `with`/`without` access. More jargony put- we add the intersection
// of all `with`/`without` accesses of the `$name` params to `_access`.
let mut _intersected_access = _access.clone();
let mut _not_first = false;
$(
if _not_first {
let mut intermediate = _access.clone();
$name::update_component_access($name, &mut intermediate);
_intersected_access.extend_intersect_filter(&intermediate);
_intersected_access.extend_access(&intermediate);
} else {
$name::update_component_access($name, &mut _intersected_access);
_not_first = true;
}
)*
*_access = _intersected_access;
}
fn update_archetype_component_access(state: &Self::State, _archetype: &Archetype, _access: &mut Access<ArchetypeComponentId>) {
let ($($name,)*) = state;
$(
if $name::matches_component_set($name, &|id| _archetype.contains(id)) {
$name::update_archetype_component_access($name, _archetype, _access);
}
)*
}
fn init_state(_world: &mut World) -> Self::State {
($($name::init_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))*
}
}
/// SAFETY: each item in the tuple is read only
unsafe impl<$($name: ReadOnlyWorldQuery),*> ReadOnlyWorldQuery for AnyOf<($($name,)*)> {}
};
}
all_tuples!(impl_tuple_fetch, 0, 15, F, S);
all_tuples!(impl_anytuple_fetch, 0, 15, F, S);
/// [`WorldQuery`] used to nullify queries by turning `Query<Q>` into `Query<NopWorldQuery<Q>>`
///
/// This will rarely be useful to consumers of `bevy_ecs`.
pub struct NopWorldQuery<Q: WorldQuery>(PhantomData<Q>);
/// SAFETY: `Self::ReadOnly` is `Self`
unsafe impl<Q: WorldQuery> WorldQuery for NopWorldQuery<Q> {
type Fetch<'w> = ();
type Item<'w> = ();
type ReadOnly = Self;
type State = Q::State;
fn shrink<'wlong: 'wshort, 'wshort>(_: ()) {}
const IS_DENSE: bool = Q::IS_DENSE;
const IS_ARCHETYPAL: bool = true;
#[inline(always)]
unsafe fn init_fetch(
_world: &World,
_state: &Q::State,
_last_change_tick: u32,
_change_tick: u32,
) {
}
unsafe fn clone_fetch<'w>(_fetch: &Self::Fetch<'w>) -> Self::Fetch<'w> {}
#[inline(always)]
unsafe fn set_archetype(
_fetch: &mut (),
_state: &Q::State,
_archetype: &Archetype,
_tables: &Table,
) {
}
#[inline(always)]
unsafe fn set_table<'w>(_fetch: &mut (), _state: &Q::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: &Q::State, _access: &mut FilteredAccess<ComponentId>) {}
fn update_archetype_component_access(
_state: &Q::State,
_archetype: &Archetype,
_access: &mut Access<ArchetypeComponentId>,
) {
}
fn init_state(world: &mut World) -> Self::State {
Q::init_state(world)
}
fn matches_component_set(
state: &Self::State,
set_contains_id: &impl Fn(ComponentId) -> bool,
) -> bool {
Q::matches_component_set(state, set_contains_id)
}
}
/// SAFETY: `NopFetch` never accesses any data
unsafe impl<Q: WorldQuery> ReadOnlyWorldQuery for NopWorldQuery<Q> {}