use crate::{ archetype::{Archetype, ArchetypeComponentId}, change_detection::Ticks, component::{Component, ComponentId, ComponentStorage, ComponentTicks, StorageType}, entity::Entity, query::{debug_checked_unreachable, Access, FilteredAccess}, storage::{ComponentSparseSet, Table}, 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) { /// 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) { /// // 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() {} /// /// assert_debug::(); /// assert_debug::(); /// ``` /// /// ## 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 { /// // Field names are not relevant, since they are never manually accessed. /// with_a: With, /// or_filter: Or<(With, Added)>, /// generic_tuple: (With, Without

), /// } /// /// fn my_system(query: Query>) { /// // ... /// } /// # bevy_ecs::system::assert_is_system(my_system); /// ``` /// /// # Safety /// /// Component access of `ROQueryFetch` must be a subset of `QueryFetch` /// and `ROQueryFetch` must match exactly the same archetypes/tables as `QueryFetch` /// /// 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::WorldQueryGats::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: for<'w> WorldQueryGats<'w> { /// The read-only variant of this [`WorldQuery`], which satisfies the [`ReadOnlyWorldQuery`] trait. type ReadOnly: ReadOnlyWorldQuery; /// State used to construct a [`Self::Fetch`](crate::query::WorldQueryGats::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::WorldQueryGats::Fetch). type State: Send + Sync + Sized; /// This function manually implements subtyping for the query items. fn shrink<'wlong: 'wshort, 'wshort>(item: QueryItem<'wlong, Self>) -> QueryItem<'wshort, Self>; /// 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, ) -> >::Fetch; /// 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` for the same /// `archetype_index` or `table_row` to be alive at the same time. unsafe fn clone_fetch<'w>( fetch: &>::Fetch, ) -> >::Fetch; /// 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 >::Fetch, 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 >::Fetch, state: &Self::State, table: &'w Table, ); /// Fetch [`Self::Item`](`WorldQueryGats::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 >::Fetch, entity: Entity, table_row: usize, ) -> >::Item; /// # 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 >::Fetch, entity: Entity, table_row: usize, ) -> 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); // 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, ); fn init_state(world: &mut World) -> Self::State; fn matches_component_set( state: &Self::State, set_contains_id: &impl Fn(ComponentId) -> bool, ) -> bool; } /// A helper trait for [`WorldQuery`] that works around Rust's lack of Generic Associated Types. /// /// **Note**: Consider using the type aliases [`QueryItem`] and [`QueryFetch`] when using `Item` or `Fetch`. pub trait WorldQueryGats<'world> { type Item; type Fetch; } /// A world query that is read only. /// /// # Safety /// /// This must only be implemented for read-only [`WorldQuery`]'s. pub unsafe trait ReadOnlyWorldQuery: WorldQuery {} /// The `Fetch` of a [`WorldQuery`], which is used to store state for each archetype/table. pub type QueryFetch<'w, Q> = >::Fetch; /// The item type returned when a [`WorldQuery`] is iterated over pub type QueryItem<'w, Q> = >::Item; /// The read-only `Fetch` of a [`WorldQuery`], which is used to store state for each archetype/table. pub type ROQueryFetch<'w, Q> = QueryFetch<'w, ::ReadOnly>; /// The read-only variant of the item type returned when a [`WorldQuery`] is iterated over immutably pub type ROQueryItem<'w, Q> = QueryItem<'w, ::ReadOnly>; /// SAFETY: no component or archetype access unsafe impl WorldQuery for Entity { type ReadOnly = Self; type State = (); fn shrink<'wlong: 'wshort, 'wshort>(item: QueryItem<'wlong, Self>) -> QueryItem<'wshort, Self> { 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, ) -> >::Fetch { } unsafe fn clone_fetch<'w>( _fetch: &>::Fetch, ) -> >::Fetch { } #[inline] unsafe fn set_archetype<'w>( _fetch: &mut >::Fetch, _state: &Self::State, _archetype: &'w Archetype, _table: &Table, ) { } #[inline] unsafe fn set_table<'w>( _fetch: &mut >::Fetch, _state: &Self::State, _table: &'w Table, ) { } #[inline(always)] unsafe fn fetch<'w>( _fetch: &mut >::Fetch, entity: Entity, _table_row: usize, ) -> >::Item { entity } fn update_component_access(_state: &Self::State, _access: &mut FilteredAccess) {} fn update_archetype_component_access( _state: &Self::State, _archetype: &Archetype, _access: &mut Access, ) { } fn init_state(_world: &mut World) {} fn matches_component_set( _state: &Self::State, _set_contains_id: &impl Fn(ComponentId) -> bool, ) -> bool { true } } impl<'w> WorldQueryGats<'w> for Entity { type Fetch = (); type Item = Entity; } /// SAFETY: access is read only unsafe impl ReadOnlyWorldQuery for Entity {} #[doc(hidden)] pub struct ReadFetch<'w, T> { // T::Storage = TableStorage table_components: Option>>, // T::Storage = SparseStorage sparse_set: Option<&'w ComponentSparseSet>, } /// SAFETY: `ROQueryFetch` is the same as `QueryFetch` unsafe impl WorldQuery for &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) .unwrap_or_else(|| debug_checked_unreachable()) }), } } unsafe fn clone_fetch<'w>( fetch: &>::Fetch, ) -> >::Fetch { 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) .unwrap_or_else(|| debug_checked_unreachable()) .get_data_slice() .into(), ); } #[inline(always)] unsafe fn fetch<'w>( fetch: &mut >::Fetch, entity: Entity, table_row: usize, ) -> >::Item { match T::Storage::STORAGE_TYPE { StorageType::Table => fetch .table_components .unwrap_or_else(|| debug_checked_unreachable()) .get(table_row) .deref(), StorageType::SparseSet => fetch .sparse_set .unwrap_or_else(|| debug_checked_unreachable()) .get(entity) .unwrap_or_else(|| debug_checked_unreachable()) .deref(), } } fn update_component_access( &component_id: &ComponentId, access: &mut FilteredAccess, ) { 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::(), ); access.add_read(component_id); } fn update_archetype_component_access( &component_id: &ComponentId, archetype: &Archetype, access: &mut Access, ) { 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::() } 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 ReadOnlyWorldQuery for &T {} impl<'w, T: Component> WorldQueryGats<'w> for &T { type Fetch = ReadFetch<'w, T>; type Item = &'w T; } #[doc(hidden)] pub struct WriteFetch<'w, T> { // T::Storage = TableStorage table_data: Option<( ThinSlicePtr<'w, UnsafeCell>, ThinSlicePtr<'w, UnsafeCell>, )>, // 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 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) .unwrap_or_else(|| debug_checked_unreachable()) }), last_change_tick, change_tick, } } unsafe fn clone_fetch<'w>( fetch: &>::Fetch, ) -> >::Fetch { 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) .unwrap_or_else(|| debug_checked_unreachable()); fetch.table_data = Some(( column.get_data_slice().into(), column.get_ticks_slice().into(), )); } #[inline(always)] unsafe fn fetch<'w>( fetch: &mut >::Fetch, entity: Entity, table_row: usize, ) -> >::Item { match T::Storage::STORAGE_TYPE { StorageType::Table => { let (table_components, table_ticks) = fetch .table_data .unwrap_or_else(|| debug_checked_unreachable()); Mut { value: table_components.get(table_row).deref_mut(), ticks: Ticks { component_ticks: table_ticks.get(table_row).deref_mut(), change_tick: fetch.change_tick, last_change_tick: fetch.last_change_tick, }, } } StorageType::SparseSet => { let (component, component_ticks) = fetch .sparse_set .unwrap_or_else(|| debug_checked_unreachable()) .get_with_ticks(entity) .unwrap_or_else(|| debug_checked_unreachable()); Mut { value: component.assert_unique().deref_mut(), ticks: Ticks { component_ticks: component_ticks.deref_mut(), change_tick: fetch.change_tick, last_change_tick: fetch.last_change_tick, }, } } } } fn update_component_access( &component_id: &ComponentId, access: &mut FilteredAccess, ) { 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::(), ); access.add_write(component_id); } fn update_archetype_component_access( &component_id: &ComponentId, archetype: &Archetype, access: &mut Access, ) { 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::() } fn matches_component_set( &state: &ComponentId, set_contains_id: &impl Fn(ComponentId) -> bool, ) -> bool { set_contains_id(state) } } impl<'w, T: Component> WorldQueryGats<'w> for &mut T { type Fetch = WriteFetch<'w, T>; type Item = Mut<'w, T>; } #[doc(hidden)] pub struct OptionFetch<'w, T: WorldQuery> { fetch: >::Fetch, matches: bool, } // SAFETY: defers to soundness of `T: WorldQuery` impl unsafe impl WorldQuery for Option { type ReadOnly = Option; type State = T::State; fn shrink<'wlong: 'wshort, 'wshort>(item: QueryItem<'wlong, Self>) -> QueryItem<'wshort, Self> { 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: &>::Fetch, ) -> >::Fetch { 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 >::Fetch, entity: Entity, table_row: usize, ) -> >::Item { fetch .matches .then(|| T::fetch(&mut fetch.fetch, entity, table_row)) } fn update_component_access(state: &T::State, access: &mut FilteredAccess) { // We don't want to add the `with`/`without` of `T` as `Option` 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>` 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, ) { 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 ReadOnlyWorldQuery for Option {} impl<'w, T: WorldQuery> WorldQueryGats<'w> for Option { type Fetch = OptionFetch<'w, T>; type Item = Option>; } /// [`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)>) { /// 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 { pub(crate) component_ticks: ComponentTicks, pub(crate) last_change_tick: u32, pub(crate) change_tick: u32, marker: PhantomData, } impl Clone for ChangeTrackers { 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 Copy for ChangeTrackers {} impl std::fmt::Debug for ChangeTrackers { 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 ChangeTrackers { /// 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_ticks: Option>>, // T::Storage = SparseStorage sparse_set: Option<&'w ComponentSparseSet>, marker: PhantomData, last_change_tick: u32, change_tick: u32, } // SAFETY: `ROQueryFetch` is the same as `QueryFetch` unsafe impl WorldQuery for ChangeTrackers { type ReadOnly = Self; type State = ComponentId; fn shrink<'wlong: 'wshort, 'wshort>(item: QueryItem<'wlong, Self>) -> QueryItem<'wshort, Self> { 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_ticks: None, sparse_set: (T::Storage::STORAGE_TYPE == StorageType::SparseSet).then(|| { world .storages() .sparse_sets .get(component_id) .unwrap_or_else(|| debug_checked_unreachable()) }), marker: PhantomData, last_change_tick, change_tick, } } unsafe fn clone_fetch<'w>( fetch: &>::Fetch, ) -> >::Fetch { ChangeTrackersFetch { table_ticks: fetch.table_ticks, 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, ) { fetch.table_ticks = Some( table .get_column(id) .unwrap_or_else(|| debug_checked_unreachable()) .get_ticks_slice() .into(), ); } #[inline(always)] unsafe fn fetch<'w>( fetch: &mut >::Fetch, entity: Entity, table_row: usize, ) -> >::Item { match T::Storage::STORAGE_TYPE { StorageType::Table => ChangeTrackers { component_ticks: { let table_ticks = fetch .table_ticks .unwrap_or_else(|| debug_checked_unreachable()); table_ticks.get(table_row).read() }, marker: PhantomData, last_change_tick: fetch.last_change_tick, change_tick: fetch.change_tick, }, StorageType::SparseSet => ChangeTrackers { component_ticks: *fetch .sparse_set .unwrap_or_else(|| debug_checked_unreachable()) .get_ticks(entity) .unwrap_or_else(|| debug_checked_unreachable()) .get(), marker: PhantomData, last_change_tick: fetch.last_change_tick, change_tick: fetch.change_tick, }, } } fn update_component_access(&id: &ComponentId, access: &mut FilteredAccess) { 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::() ); access.add_read(id); } fn update_archetype_component_access( &id: &ComponentId, archetype: &Archetype, access: &mut Access, ) { 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::() } 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 ReadOnlyWorldQuery for ChangeTrackers {} impl<'w, T: Component> WorldQueryGats<'w> for ChangeTrackers { type Fetch = ChangeTrackersFetch<'w, T>; type Item = ChangeTrackers; } macro_rules! impl_tuple_fetch { ($(($name: ident, $state: ident)),*) => { #[allow(unused_variables)] #[allow(non_snake_case)] impl<'w, $($name: WorldQueryGats<'w>),*> WorldQueryGats<'w> for ($($name,)*) { type Fetch = ($($name::Fetch,)*); type Item = ($($name::Item,)*); } #[allow(non_snake_case)] #[allow(clippy::unused_unit)] // SAFETY: defers to soundness `$name: WorldQuery` impl unsafe impl<$($name: WorldQuery),*> WorldQuery for ($($name,)*) { type ReadOnly = ($($name::ReadOnly,)*); type State = ($($name::State,)*); fn shrink<'wlong: 'wshort, 'wshort>(item: QueryItem<'wlong, Self>) -> QueryItem<'wshort, Self> { let ($($name,)*) = item; ($( $name::shrink($name), )*) } #[allow(clippy::unused_unit)] unsafe fn init_fetch<'w>(_world: &'w World, state: &Self::State, _last_change_tick: u32, _change_tick: u32) -> >::Fetch { let ($($name,)*) = state; ($($name::init_fetch(_world, $name, _last_change_tick, _change_tick),)*) } unsafe fn clone_fetch<'w>( fetch: &>::Fetch, ) -> >::Fetch { let ($($name,)*) = &fetch; ($($name::clone_fetch($name),)*) } const IS_DENSE: bool = true $(&& $name::IS_DENSE)*; const IS_ARCHETYPAL: bool = true $(&& $name::IS_ARCHETYPAL)*; #[inline] unsafe fn set_archetype<'w>( _fetch: &mut >::Fetch, _state: &Self::State, _archetype: &'w Archetype, _table: &'w Table ) { let ($($name,)*) = _fetch; let ($($state,)*) = _state; $($name::set_archetype($name, $state, _archetype, _table);)* } #[inline] unsafe fn set_table<'w>(_fetch: &mut >::Fetch, _state: &Self::State, _table: &'w Table) { let ($($name,)*) = _fetch; let ($($state,)*) = _state; $($name::set_table($name, $state, _table);)* } #[inline(always)] #[allow(clippy::unused_unit)] unsafe fn fetch<'w>( _fetch: &mut >::Fetch, _entity: Entity, _table_row: usize ) -> >::Item { let ($($name,)*) = _fetch; ($($name::fetch($name, _entity, _table_row),)*) } #[inline(always)] unsafe fn filter_fetch<'w>( _fetch: &mut >::Fetch, _entity: Entity, _table_row: usize ) -> bool { let ($($name,)*) = _fetch; true $(&& $name::filter_fetch($name, _entity, _table_row))* } fn update_component_access(state: &Self::State, _access: &mut FilteredAccess) { let ($($name,)*) = state; $($name::update_component_access($name, _access);)* } fn update_archetype_component_access(state: &Self::State, _archetype: &Archetype, _access: &mut Access) { let ($($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>` is equivalent to `Query<(Option<&A>, Option<&B>, Option<&mut C>), Or<(With, With, With)>>`. /// Each of the components in `T` is returned as an `Option`, as with `Option` queries. /// Entities are guaranteed to have at least one of the components in `T`. pub struct AnyOf(PhantomData); macro_rules! impl_anytuple_fetch { ($(($name: ident, $state: ident)),*) => { #[allow(unused_variables)] #[allow(non_snake_case)] impl<'w, $($name: WorldQueryGats<'w>),*> WorldQueryGats<'w> for AnyOf<($($name,)*)> { type Fetch = ($(($name::Fetch, bool),)*); type Item = ($(Option<$name::Item>,)*); } #[allow(non_snake_case)] #[allow(clippy::unused_unit)] // SAFETY: defers to soundness of `$name: WorldQuery` impl unsafe impl<$($name: WorldQuery),*> WorldQuery for AnyOf<($($name,)*)> { type ReadOnly = AnyOf<($($name::ReadOnly,)*)>; type State = ($($name::State,)*); fn shrink<'wlong: 'wshort, 'wshort>(item: QueryItem<'wlong, Self>) -> QueryItem<'wshort, Self> { let ($($name,)*) = item; ($( $name.map($name::shrink), )*) } #[allow(clippy::unused_unit)] unsafe fn init_fetch<'w>(_world: &'w World, state: &Self::State, _last_change_tick: u32, _change_tick: u32) -> >::Fetch { let ($($name,)*) = state; ($(($name::init_fetch(_world, $name, _last_change_tick, _change_tick), false),)*) } unsafe fn clone_fetch<'w>( fetch: &>::Fetch, ) -> >::Fetch { let ($($name,)*) = &fetch; ($(($name::clone_fetch(& $name.0), $name.1),)*) } const IS_DENSE: bool = true $(&& $name::IS_DENSE)*; const IS_ARCHETYPAL: bool = true $(&& $name::IS_ARCHETYPAL)*; #[inline] unsafe fn set_archetype<'w>( _fetch: &mut >::Fetch, _state: &Self::State, _archetype: &'w Archetype, _table: &'w Table ) { let ($($name,)*) = _fetch; let ($($state,)*) = _state; $( $name.1 = $name::matches_component_set($state, &|id| _archetype.contains(id)); if $name.1 { $name::set_archetype(&mut $name.0, $state, _archetype, _table); } )* } #[inline] unsafe fn set_table<'w>(_fetch: &mut >::Fetch, _state: &Self::State, _table: &'w Table) { let ($($name,)*) = _fetch; let ($($state,)*) = _state; $( $name.1 = $name::matches_component_set($state, &|id| _table.has_column(id)); if $name.1 { $name::set_table(&mut $name.0, $state, _table); } )* } #[inline(always)] #[allow(clippy::unused_unit)] unsafe fn fetch<'w>( _fetch: &mut >::Fetch, _entity: Entity, _table_row: usize ) -> >::Item { let ($($name,)*) = _fetch; ($( $name.1.then(|| $name::fetch(&mut $name.0, _entity, _table_row)), )*) } fn update_component_access(state: &Self::State, _access: &mut FilteredAccess) { let ($($name,)*) = state; // We do not unconditionally add `$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> // // If we were to unconditionally add `$name`'s `with`/`without` accesses then `AnyOf<(&A, ())>` // would have a `With` access which is incorrect as this `WorldQuery` will match entities that // do not have the `A` component. This is the same logic as the `Or<...>: WorldQuery` impl. // // The correct thing to do here is to only add a `with`/`without` access to `_access` if all // `$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) { 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` into `Query>` /// /// This will rarely be useful to consumers of `bevy_ecs`. pub struct NopWorldQuery(PhantomData); /// SAFETY: `Self::ReadOnly` is `Self` unsafe impl WorldQuery for NopWorldQuery { 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: &>::Fetch, ) -> >::Fetch { } #[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 >::Fetch, _entity: Entity, _table_row: usize, ) -> >::Item { } fn update_component_access(_state: &Q::State, _access: &mut FilteredAccess) {} fn update_archetype_component_access( _state: &Q::State, _archetype: &Archetype, _access: &mut Access, ) { } 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) } } impl<'a, Q: WorldQuery> WorldQueryGats<'a> for NopWorldQuery { type Fetch = (); type Item = (); } /// SAFETY: `NopFetch` never accesses any data unsafe impl ReadOnlyWorldQuery for NopWorldQuery {}