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state.rs
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use crate::{
archetype::{Archetype, ArchetypeComponentId, ArchetypeGeneration, ArchetypeId},
batching::BatchingStrategy,
component::{ComponentId, Tick},
entity::{Entity, EntityBorrow, EntitySet},
entity_disabling::DefaultQueryFilters,
prelude::FromWorld,
query::{
Access, DebugCheckedUnwrap, FilteredAccess, QueryCombinationIter, QueryIter, QueryParIter,
WorldQuery,
},
storage::{SparseSetIndex, TableId},
system::Query,
world::{unsafe_world_cell::UnsafeWorldCell, World, WorldId},
};
use alloc::vec::Vec;
use core::{fmt, mem::MaybeUninit, ptr};
use fixedbitset::FixedBitSet;
use log::warn;
#[cfg(feature = "trace")]
use tracing::Span;
use super::{
NopWorldQuery, QueryBuilder, QueryData, QueryEntityError, QueryFilter, QueryManyIter,
QueryManyUniqueIter, QuerySingleError, ROQueryItem,
};
/// An ID for either a table or an archetype. Used for Query iteration.
///
/// Query iteration is exclusively dense (over tables) or archetypal (over archetypes) based on whether
/// the query filters are dense or not. This is represented by the [`QueryState::is_dense`] field.
///
/// Note that `D::IS_DENSE` and `F::IS_DENSE` have no relationship with `QueryState::is_dense` and
/// any combination of their values can happen.
///
/// This is a union instead of an enum as the usage is determined at compile time, as all [`StorageId`]s for
/// a [`QueryState`] will be all [`TableId`]s or all [`ArchetypeId`]s, and not a mixture of both. This
/// removes the need for discriminator to minimize memory usage and branching during iteration, but requires
/// a safety invariant be verified when disambiguating them.
///
/// # Safety
/// Must be initialized and accessed as a [`TableId`], if both generic parameters to the query are dense.
/// Must be initialized and accessed as an [`ArchetypeId`] otherwise.
#[derive(Clone, Copy)]
pub(super) union StorageId {
pub(super) table_id: TableId,
pub(super) archetype_id: ArchetypeId,
}
/// Provides scoped access to a [`World`] state according to a given [`QueryData`] and [`QueryFilter`].
///
/// This data is cached between system runs, and is used to:
/// - store metadata about which [`Table`] or [`Archetype`] are matched by the query. "Matched" means
/// that the query will iterate over the data in the matched table/archetype.
/// - cache the [`State`] needed to compute the [`Fetch`] struct used to retrieve data
/// from a specific [`Table`] or [`Archetype`]
/// - build iterators that can iterate over the query results
///
/// [`State`]: crate::query::world_query::WorldQuery::State
/// [`Fetch`]: crate::query::world_query::WorldQuery::Fetch
/// [`Table`]: crate::storage::Table
#[repr(C)]
// SAFETY NOTE:
// Do not add any new fields that use the `D` or `F` generic parameters as this may
// make `QueryState::as_transmuted_state` unsound if not done with care.
pub struct QueryState<D: QueryData, F: QueryFilter = ()> {
world_id: WorldId,
pub(crate) archetype_generation: ArchetypeGeneration,
/// Metadata about the [`Table`](crate::storage::Table)s matched by this query.
pub(crate) matched_tables: FixedBitSet,
/// Metadata about the [`Archetype`]s matched by this query.
pub(crate) matched_archetypes: FixedBitSet,
/// [`FilteredAccess`] computed by combining the `D` and `F` access. Used to check which other queries
/// this query can run in parallel with.
pub(crate) component_access: FilteredAccess<ComponentId>,
// NOTE: we maintain both a bitset and a vec because iterating the vec is faster
pub(super) matched_storage_ids: Vec<StorageId>,
// Represents whether this query iteration is dense or not. When this is true
// `matched_storage_ids` stores `TableId`s, otherwise it stores `ArchetypeId`s.
pub(super) is_dense: bool,
pub(crate) fetch_state: D::State,
pub(crate) filter_state: F::State,
#[cfg(feature = "trace")]
par_iter_span: Span,
}
impl<D: QueryData, F: QueryFilter> Clone for QueryState<D, F>
where
D::State: Clone,
F::State: Clone,
{
fn clone(&self) -> Self {
Self {
world_id: self.world_id,
archetype_generation: self.archetype_generation,
matched_tables: self.matched_tables.clone(),
matched_archetypes: self.matched_archetypes.clone(),
component_access: self.component_access.clone(),
matched_storage_ids: self.matched_storage_ids.clone(),
is_dense: self.is_dense,
fetch_state: self.fetch_state.clone(),
filter_state: self.filter_state.clone(),
#[cfg(feature = "trace")]
par_iter_span: self.par_iter_span.clone(),
}
}
}
impl<D: QueryData, F: QueryFilter> fmt::Debug for QueryState<D, F> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("QueryState")
.field("world_id", &self.world_id)
.field("matched_table_count", &self.matched_tables.count_ones(..))
.field(
"matched_archetype_count",
&self.matched_archetypes.count_ones(..),
)
.finish_non_exhaustive()
}
}
impl<D: QueryData, F: QueryFilter> FromWorld for QueryState<D, F> {
fn from_world(world: &mut World) -> Self {
world.query_filtered()
}
}
impl<D: QueryData, F: QueryFilter> QueryState<D, F> {
/// Converts this `QueryState` reference to a `QueryState` that does not access anything mutably.
pub fn as_readonly(&self) -> &QueryState<D::ReadOnly, F> {
// SAFETY: invariant on `WorldQuery` trait upholds that `D::ReadOnly` and `F::ReadOnly`
// have a subset of the access, and match the exact same archetypes/tables as `D`/`F` respectively.
unsafe { self.as_transmuted_state::<D::ReadOnly, F>() }
}
/// Converts this `QueryState` reference to a `QueryState` that does not return any data
/// which can be faster.
///
/// This doesn't use `NopWorldQuery` as it loses filter functionality, for example
/// `NopWorldQuery<Changed<T>>` is functionally equivalent to `With<T>`.
pub(crate) fn as_nop(&self) -> &QueryState<NopWorldQuery<D>, F> {
// SAFETY: `NopWorldQuery` doesn't have any accesses and defers to
// `D` for table/archetype matching
unsafe { self.as_transmuted_state::<NopWorldQuery<D>, F>() }
}
/// Converts this `QueryState` reference to any other `QueryState` with
/// the same `WorldQuery::State` associated types.
///
/// Consider using `as_readonly` or `as_nop` instead which are safe functions.
///
/// # Safety
///
/// `NewD` must have a subset of the access that `D` does and match the exact same archetypes/tables
/// `NewF` must have a subset of the access that `F` does and match the exact same archetypes/tables
pub(crate) unsafe fn as_transmuted_state<
NewD: QueryData<State = D::State>,
NewF: QueryFilter<State = F::State>,
>(
&self,
) -> &QueryState<NewD, NewF> {
&*ptr::from_ref(self).cast::<QueryState<NewD, NewF>>()
}
/// Returns the components accessed by this query.
pub fn component_access(&self) -> &FilteredAccess<ComponentId> {
&self.component_access
}
/// Returns the tables matched by this query.
pub fn matched_tables(&self) -> impl Iterator<Item = TableId> + '_ {
self.matched_tables.ones().map(TableId::from_usize)
}
/// Returns the archetypes matched by this query.
pub fn matched_archetypes(&self) -> impl Iterator<Item = ArchetypeId> + '_ {
self.matched_archetypes.ones().map(ArchetypeId::new)
}
/// Creates a new [`QueryState`] from a given [`World`] and inherits the result of `world.id()`.
pub fn new(world: &mut World) -> Self {
let mut state = Self::new_uninitialized(world);
state.update_archetypes(world);
state
}
/// Creates a new [`QueryState`] from an immutable [`World`] reference and inherits the result of `world.id()`.
///
/// This function may fail if, for example,
/// the components that make up this query have not been registered into the world.
pub fn try_new(world: &World) -> Option<Self> {
let mut state = Self::try_new_uninitialized(world)?;
state.update_archetypes(world);
Some(state)
}
/// Identical to `new`, but it populates the provided `access` with the matched results.
pub(crate) fn new_with_access(
world: &mut World,
access: &mut Access<ArchetypeComponentId>,
) -> Self {
let mut state = Self::new_uninitialized(world);
for archetype in world.archetypes.iter() {
// SAFETY: The state was just initialized from the `world` above, and the archetypes being added
// come directly from the same world.
unsafe {
if state.new_archetype_internal(archetype) {
state.update_archetype_component_access(archetype, access);
}
}
}
state.archetype_generation = world.archetypes.generation();
// Resource access is not part of any archetype and must be handled separately
if state.component_access.access().has_read_all_resources() {
access.read_all_resources();
} else {
for component_id in state.component_access.access().resource_reads() {
access.add_resource_read(world.initialize_resource_internal(component_id).id());
}
}
debug_assert!(
!state.component_access.access().has_any_resource_write(),
"Mutable resource access in queries is not allowed"
);
state
}
/// Creates a new [`QueryState`] but does not populate it with the matched results from the World yet
///
/// `new_archetype` and its variants must be called on all of the World's archetypes before the
/// state can return valid query results.
pub fn new_uninitialized(world: &mut World) -> Self {
let fetch_state = D::init_state(world);
let filter_state = F::init_state(world);
Self::from_states_uninitialized(world, fetch_state, filter_state)
}
/// Creates a new [`QueryState`] but does not populate it with the matched results from the World yet
///
/// `new_archetype` and its variants must be called on all of the World's archetypes before the
/// state can return valid query results.
fn try_new_uninitialized(world: &World) -> Option<Self> {
let fetch_state = D::get_state(world.components())?;
let filter_state = F::get_state(world.components())?;
Some(Self::from_states_uninitialized(
world,
fetch_state,
filter_state,
))
}
/// Creates a new [`QueryState`] but does not populate it with the matched results from the World yet
///
/// `new_archetype` and its variants must be called on all of the World's archetypes before the
/// state can return valid query results.
fn from_states_uninitialized(
world: &World,
fetch_state: <D as WorldQuery>::State,
filter_state: <F as WorldQuery>::State,
) -> Self {
let mut component_access = FilteredAccess::default();
D::update_component_access(&fetch_state, &mut component_access);
// Use a temporary empty FilteredAccess for filters. This prevents them from conflicting with the
// main Query's `fetch_state` access. Filters are allowed to conflict with the main query fetch
// because they are evaluated *before* a specific reference is constructed.
let mut filter_component_access = FilteredAccess::default();
F::update_component_access(&filter_state, &mut filter_component_access);
// Merge the temporary filter access with the main access. This ensures that filter access is
// properly considered in a global "cross-query" context (both within systems and across systems).
component_access.extend(&filter_component_access);
// For queries without dynamic filters the dense-ness of the query is equal to the dense-ness
// of its static type parameters.
let mut is_dense = D::IS_DENSE && F::IS_DENSE;
if let Some(default_filters) = world.get_resource::<DefaultQueryFilters>() {
default_filters.apply(&mut component_access);
is_dense &= default_filters.is_dense(world.components());
}
Self {
world_id: world.id(),
archetype_generation: ArchetypeGeneration::initial(),
matched_storage_ids: Vec::new(),
is_dense,
fetch_state,
filter_state,
component_access,
matched_tables: Default::default(),
matched_archetypes: Default::default(),
#[cfg(feature = "trace")]
par_iter_span: tracing::info_span!(
"par_for_each",
query = core::any::type_name::<D>(),
filter = core::any::type_name::<F>(),
),
}
}
/// Creates a new [`QueryState`] from a given [`QueryBuilder`] and inherits its [`FilteredAccess`].
pub fn from_builder(builder: &mut QueryBuilder<D, F>) -> Self {
let mut fetch_state = D::init_state(builder.world_mut());
let filter_state = F::init_state(builder.world_mut());
D::set_access(&mut fetch_state, builder.access());
let mut component_access = builder.access().clone();
// For dynamic queries the dense-ness is given by the query builder.
let mut is_dense = builder.is_dense();
if let Some(default_filters) = builder.world().get_resource::<DefaultQueryFilters>() {
default_filters.apply(&mut component_access);
is_dense &= default_filters.is_dense(builder.world().components());
}
let mut state = Self {
world_id: builder.world().id(),
archetype_generation: ArchetypeGeneration::initial(),
matched_storage_ids: Vec::new(),
is_dense,
fetch_state,
filter_state,
component_access,
matched_tables: Default::default(),
matched_archetypes: Default::default(),
#[cfg(feature = "trace")]
par_iter_span: tracing::info_span!(
"par_for_each",
data = core::any::type_name::<D>(),
filter = core::any::type_name::<F>(),
),
};
state.update_archetypes(builder.world());
state
}
/// Creates a [`Query`] from the given [`QueryState`] and [`World`].
///
/// This will create read-only queries, see [`Self::query_mut`] for mutable queries.
pub fn query<'w, 's>(&'s mut self, world: &'w World) -> Query<'w, 's, D::ReadOnly, F> {
self.update_archetypes(world);
self.query_manual(world)
}
/// Creates a [`Query`] from the given [`QueryState`] and [`World`].
///
/// This method is slightly more efficient than [`QueryState::query`] in some situations, since
/// it does not update this instance's internal cache. The resulting query may skip an entity that
/// belongs to an archetype that has not been cached.
///
/// To ensure that the cache is up to date, call [`QueryState::update_archetypes`] before this method.
/// The cache is also updated in [`QueryState::new`], [`QueryState::get`], or any method with mutable
/// access to `self`.
///
/// This will create read-only queries, see [`Self::query_mut`] for mutable queries.
pub fn query_manual<'w, 's>(&'s self, world: &'w World) -> Query<'w, 's, D::ReadOnly, F> {
// SAFETY: We have read access to the entire world, and we call `as_readonly()` so the query only performs read access.
unsafe {
self.as_readonly()
.query_unchecked_manual(world.as_unsafe_world_cell_readonly())
}
}
/// Creates a [`Query`] from the given [`QueryState`] and [`World`].
pub fn query_mut<'w, 's>(&'s mut self, world: &'w mut World) -> Query<'w, 's, D, F> {
let last_run = world.last_change_tick();
let this_run = world.change_tick();
// SAFETY: We have exclusive access to the entire world.
unsafe { self.query_unchecked_with_ticks(world.as_unsafe_world_cell(), last_run, this_run) }
}
/// Creates a [`Query`] from the given [`QueryState`] and [`World`].
///
/// # Safety
///
/// This does not check for mutable query correctness. To be safe, make sure mutable queries
/// have unique access to the components they query.
pub unsafe fn query_unchecked<'w, 's>(
&'s mut self,
world: UnsafeWorldCell<'w>,
) -> Query<'w, 's, D, F> {
self.update_archetypes_unsafe_world_cell(world);
// SAFETY: Caller ensures we have the required access
unsafe { self.query_unchecked_manual(world) }
}
/// Creates a [`Query`] from the given [`QueryState`] and [`World`].
///
/// This method is slightly more efficient than [`QueryState::query_unchecked`] in some situations, since
/// it does not update this instance's internal cache. The resulting query may skip an entity that
/// belongs to an archetype that has not been cached.
///
/// To ensure that the cache is up to date, call [`QueryState::update_archetypes`] before this method.
/// The cache is also updated in [`QueryState::new`], [`QueryState::get`], or any method with mutable
/// access to `self`.
///
/// # Safety
///
/// This does not check for mutable query correctness. To be safe, make sure mutable queries
/// have unique access to the components they query.
pub unsafe fn query_unchecked_manual<'w, 's>(
&'s self,
world: UnsafeWorldCell<'w>,
) -> Query<'w, 's, D, F> {
let last_run = world.last_change_tick();
let this_run = world.change_tick();
// SAFETY: The caller ensured we have the correct access to the world.
unsafe { self.query_unchecked_manual_with_ticks(world, last_run, this_run) }
}
/// Creates a [`Query`] from the given [`QueryState`] and [`World`].
///
/// # Safety
///
/// This does not check for mutable query correctness. To be safe, make sure mutable queries
/// have unique access to the components they query.
pub unsafe fn query_unchecked_with_ticks<'w, 's>(
&'s mut self,
world: UnsafeWorldCell<'w>,
last_run: Tick,
this_run: Tick,
) -> Query<'w, 's, D, F> {
self.update_archetypes_unsafe_world_cell(world);
// SAFETY: The caller ensured we have the correct access to the world.
unsafe { self.query_unchecked_manual_with_ticks(world, last_run, this_run) }
}
/// Creates a [`Query`] from the given [`QueryState`] and [`World`].
///
/// This method is slightly more efficient than [`QueryState::query_unchecked_with_ticks`] in some situations, since
/// it does not update this instance's internal cache. The resulting query may skip an entity that
/// belongs to an archetype that has not been cached.
///
/// To ensure that the cache is up to date, call [`QueryState::update_archetypes`] before this method.
/// The cache is also updated in [`QueryState::new`], [`QueryState::get`], or any method with mutable
/// access to `self`.
///
/// # Safety
///
/// This does not check for mutable query correctness. To be safe, make sure mutable queries
/// have unique access to the components they query.
pub unsafe fn query_unchecked_manual_with_ticks<'w, 's>(
&'s self,
world: UnsafeWorldCell<'w>,
last_run: Tick,
this_run: Tick,
) -> Query<'w, 's, D, F> {
self.validate_world(world.id());
// SAFETY:
// - The caller ensured we have the correct access to the world.
// - `validate_world` did not panic, so the world matches.
unsafe { Query::new(world, self, last_run, this_run) }
}
/// Checks if the query is empty for the given [`World`], where the last change and current tick are given.
///
/// This is equivalent to `self.iter().next().is_none()`, and thus the worst case runtime will be `O(n)`
/// where `n` is the number of *potential* matches. This can be notably expensive for queries that rely
/// on non-archetypal filters such as [`Added`] or [`Changed`] which must individually check each query
/// result for a match.
///
/// # Panics
///
/// If `world` does not match the one used to call `QueryState::new` for this instance.
///
/// [`Added`]: crate::query::Added
/// [`Changed`]: crate::query::Changed
#[inline]
pub fn is_empty(&self, world: &World, last_run: Tick, this_run: Tick) -> bool {
self.validate_world(world.id());
// SAFETY:
// - We have read-only access to the entire world.
// - The world has been validated.
unsafe {
self.is_empty_unsafe_world_cell(
world.as_unsafe_world_cell_readonly(),
last_run,
this_run,
)
}
}
/// Returns `true` if the given [`Entity`] matches the query.
///
/// This is always guaranteed to run in `O(1)` time.
#[inline]
pub fn contains(&self, entity: Entity, world: &World, last_run: Tick, this_run: Tick) -> bool {
// SAFETY: NopFetch does not access any members while &self ensures no one has exclusive access
unsafe {
self.as_nop()
.get_unchecked_manual(
world.as_unsafe_world_cell_readonly(),
entity,
last_run,
this_run,
)
.is_ok()
}
}
/// Checks if the query is empty for the given [`UnsafeWorldCell`].
///
/// # Safety
///
/// - `world` must have permission to read any components required by this instance's `F` [`QueryFilter`].
/// - `world` must match the one used to create this [`QueryState`].
#[inline]
pub(crate) unsafe fn is_empty_unsafe_world_cell(
&self,
world: UnsafeWorldCell,
last_run: Tick,
this_run: Tick,
) -> bool {
// SAFETY:
// - The caller ensures that `world` has permission to access any data used by the filter.
// - The caller ensures that the world matches.
unsafe {
self.as_nop()
.iter_unchecked_manual(world, last_run, this_run)
.next()
.is_none()
}
}
/// Updates the state's internal view of the [`World`]'s archetypes. If this is not called before querying data,
/// the results may not accurately reflect what is in the `world`.
///
/// This is only required if a `manual` method (such as [`Self::get_manual`]) is being called, and it only needs to
/// be called if the `world` has been structurally mutated (i.e. added/removed a component or resource). Users using
/// non-`manual` methods such as [`QueryState::get`] do not need to call this as it will be automatically called for them.
///
/// If you have an [`UnsafeWorldCell`] instead of `&World`, consider using [`QueryState::update_archetypes_unsafe_world_cell`].
///
/// # Panics
///
/// If `world` does not match the one used to call `QueryState::new` for this instance.
#[inline]
pub fn update_archetypes(&mut self, world: &World) {
self.update_archetypes_unsafe_world_cell(world.as_unsafe_world_cell_readonly());
}
/// Updates the state's internal view of the `world`'s archetypes. If this is not called before querying data,
/// the results may not accurately reflect what is in the `world`.
///
/// This is only required if a `manual` method (such as [`Self::get_manual`]) is being called, and it only needs to
/// be called if the `world` has been structurally mutated (i.e. added/removed a component or resource). Users using
/// non-`manual` methods such as [`QueryState::get`] do not need to call this as it will be automatically called for them.
///
/// # Note
///
/// This method only accesses world metadata.
///
/// # Panics
///
/// If `world` does not match the one used to call `QueryState::new` for this instance.
pub fn update_archetypes_unsafe_world_cell(&mut self, world: UnsafeWorldCell) {
self.validate_world(world.id());
if self.component_access.required.is_empty() {
let archetypes = world.archetypes();
let old_generation =
core::mem::replace(&mut self.archetype_generation, archetypes.generation());
for archetype in &archetypes[old_generation..] {
// SAFETY: The validate_world call ensures that the world is the same the QueryState
// was initialized from.
unsafe {
self.new_archetype_internal(archetype);
}
}
} else {
// skip if we are already up to date
if self.archetype_generation == world.archetypes().generation() {
return;
}
// if there are required components, we can optimize by only iterating through archetypes
// that contain at least one of the required components
let potential_archetypes = self
.component_access
.required
.ones()
.filter_map(|idx| {
let component_id = ComponentId::get_sparse_set_index(idx);
world
.archetypes()
.component_index()
.get(&component_id)
.map(|index| index.keys())
})
// select the component with the fewest archetypes
.min_by_key(ExactSizeIterator::len);
if let Some(archetypes) = potential_archetypes {
for archetype_id in archetypes {
// exclude archetypes that have already been processed
if archetype_id < &self.archetype_generation.0 {
continue;
}
// SAFETY: get_potential_archetypes only returns archetype ids that are valid for the world
let archetype = &world.archetypes()[*archetype_id];
// SAFETY: The validate_world call ensures that the world is the same the QueryState
// was initialized from.
unsafe {
self.new_archetype_internal(archetype);
}
}
}
self.archetype_generation = world.archetypes().generation();
}
}
/// # Panics
///
/// If `world_id` does not match the [`World`] used to call `QueryState::new` for this instance.
///
/// Many unsafe query methods require the world to match for soundness. This function is the easiest
/// way of ensuring that it matches.
#[inline]
#[track_caller]
pub fn validate_world(&self, world_id: WorldId) {
#[inline(never)]
#[track_caller]
#[cold]
fn panic_mismatched(this: WorldId, other: WorldId) -> ! {
panic!("Encountered a mismatched World. This QueryState was created from {this:?}, but a method was called using {other:?}.");
}
if self.world_id != world_id {
panic_mismatched(self.world_id, world_id);
}
}
/// Update the current [`QueryState`] with information from the provided [`Archetype`]
/// (if applicable, i.e. if the archetype has any intersecting [`ComponentId`] with the current [`QueryState`]).
///
/// The passed in `access` will be updated with any new accesses introduced by the new archetype.
///
/// # Safety
/// `archetype` must be from the `World` this state was initialized from.
pub unsafe fn new_archetype(
&mut self,
archetype: &Archetype,
access: &mut Access<ArchetypeComponentId>,
) {
// SAFETY: The caller ensures that `archetype` is from the World the state was initialized from.
let matches = unsafe { self.new_archetype_internal(archetype) };
if matches {
// SAFETY: The caller ensures that `archetype` is from the World the state was initialized from.
unsafe { self.update_archetype_component_access(archetype, access) };
}
}
/// Returns `true` if the given `archetype` matches the query. Otherwise, returns `false`.
pub fn archetype_matches(&self, archetype: &Archetype) -> bool {
D::matches_component_set(&self.fetch_state, &|id| archetype.contains(id))
&& F::matches_component_set(&self.filter_state, &|id| archetype.contains(id))
&& self.matches_component_set(&|id| archetype.contains(id))
}
/// Process the given [`Archetype`] to update internal metadata about the [`Table`](crate::storage::Table)s
/// and [`Archetype`]s that are matched by this query.
///
/// # Safety
/// `archetype` must be from the `World` this state was initialized from,
/// and must match the current query.
pub unsafe fn new_archetype_unchecked(&mut self, archetype: &Archetype) {
let archetype_index = archetype.id().index();
if !self.matched_archetypes.contains(archetype_index) {
self.matched_archetypes.grow_and_insert(archetype_index);
if !self.is_dense {
self.matched_storage_ids.push(StorageId {
archetype_id: archetype.id(),
});
}
}
let table_index = archetype.table_id().as_usize();
if !self.matched_tables.contains(table_index) {
self.matched_tables.grow_and_insert(table_index);
if self.is_dense {
self.matched_storage_ids.push(StorageId {
table_id: archetype.table_id(),
});
}
}
}
/// Process the given [`Archetype`] to update internal metadata about the [`Table`](crate::storage::Table)s
/// and [`Archetype`]s that are matched by this query.
///
/// Returns `true` if the given `archetype` matches the query. Otherwise, returns `false`.
/// If there is no match, then there is no need to update the query's [`FilteredAccess`].
///
/// # Safety
/// `archetype` must be from the `World` this state was initialized from.
unsafe fn new_archetype_internal(&mut self, archetype: &Archetype) -> bool {
if self.archetype_matches(archetype) {
self.new_archetype_unchecked(archetype);
true
} else {
false
}
}
/// Returns `true` if this query matches a set of components. Otherwise, returns `false`.
pub fn matches_component_set(&self, set_contains_id: &impl Fn(ComponentId) -> bool) -> bool {
self.component_access.filter_sets.iter().any(|set| {
set.with
.ones()
.all(|index| set_contains_id(ComponentId::get_sparse_set_index(index)))
&& set
.without
.ones()
.all(|index| !set_contains_id(ComponentId::get_sparse_set_index(index)))
})
}
/// For the given `archetype`, adds any component accessed used by this query's underlying [`FilteredAccess`] to `access`.
///
/// The passed in `access` will be updated with any new accesses introduced by the new archetype.
///
/// # Safety
/// `archetype` must be from the `World` this state was initialized from.
pub unsafe fn update_archetype_component_access(
&mut self,
archetype: &Archetype,
access: &mut Access<ArchetypeComponentId>,
) {
// As a fast path, we can iterate directly over the components involved
// if the `access` isn't inverted.
let (component_reads_and_writes, component_reads_and_writes_inverted) =
self.component_access.access.component_reads_and_writes();
let (component_writes, component_writes_inverted) =
self.component_access.access.component_writes();
if !component_reads_and_writes_inverted && !component_writes_inverted {
component_reads_and_writes.for_each(|id| {
if let Some(id) = archetype.get_archetype_component_id(id) {
access.add_component_read(id);
}
});
component_writes.for_each(|id| {
if let Some(id) = archetype.get_archetype_component_id(id) {
access.add_component_write(id);
}
});
return;
}
for (component_id, archetype_component_id) in
archetype.components_with_archetype_component_id()
{
if self
.component_access
.access
.has_component_read(component_id)
{
access.add_component_read(archetype_component_id);
}
if self
.component_access
.access
.has_component_write(component_id)
{
access.add_component_write(archetype_component_id);
}
}
}
/// Use this to transform a [`QueryState`] into a more generic [`QueryState`].
/// This can be useful for passing to another function that might take the more general form.
/// See [`Query::transmute_lens`](crate::system::Query::transmute_lens) for more details.
///
/// You should not call [`update_archetypes`](Self::update_archetypes) on the returned [`QueryState`] as the result will be unpredictable.
/// You might end up with a mix of archetypes that only matched the original query + archetypes that only match
/// the new [`QueryState`]. Most of the safe methods on [`QueryState`] call [`QueryState::update_archetypes`] internally, so this
/// best used through a [`Query`]
pub fn transmute<'a, NewD: QueryData>(
&self,
world: impl Into<UnsafeWorldCell<'a>>,
) -> QueryState<NewD> {
self.transmute_filtered::<NewD, ()>(world.into())
}
/// Creates a new [`QueryState`] with the same underlying [`FilteredAccess`], matched tables and archetypes
/// as self but with a new type signature.
///
/// Panics if `NewD` or `NewF` require accesses that this query does not have.
pub fn transmute_filtered<'a, NewD: QueryData, NewF: QueryFilter>(
&self,
world: impl Into<UnsafeWorldCell<'a>>,
) -> QueryState<NewD, NewF> {
let world = world.into();
self.validate_world(world.id());
let mut component_access = FilteredAccess::default();
let mut fetch_state = NewD::get_state(world.components()).expect("Could not create fetch_state, Please initialize all referenced components before transmuting.");
let filter_state = NewF::get_state(world.components()).expect("Could not create filter_state, Please initialize all referenced components before transmuting.");
NewD::set_access(&mut fetch_state, &self.component_access);
NewD::update_component_access(&fetch_state, &mut component_access);
let mut filter_component_access = FilteredAccess::default();
NewF::update_component_access(&filter_state, &mut filter_component_access);
component_access.extend(&filter_component_access);
assert!(
component_access.is_subset(&self.component_access),
"Transmuted state for {} attempts to access terms that are not allowed by original state {}.",
core::any::type_name::<(NewD, NewF)>(), core::any::type_name::<(D, F)>()
);
QueryState {
world_id: self.world_id,
archetype_generation: self.archetype_generation,
matched_storage_ids: self.matched_storage_ids.clone(),
is_dense: self.is_dense,
fetch_state,
filter_state,
component_access: self.component_access.clone(),
matched_tables: self.matched_tables.clone(),
matched_archetypes: self.matched_archetypes.clone(),
#[cfg(feature = "trace")]
par_iter_span: tracing::info_span!(
"par_for_each",
query = core::any::type_name::<NewD>(),
filter = core::any::type_name::<NewF>(),
),
}
}
/// Use this to combine two queries. The data accessed will be the intersection
/// of archetypes included in both queries. This can be useful for accessing a
/// subset of the entities between two queries.
///
/// You should not call `update_archetypes` on the returned `QueryState` as the result
/// could be unpredictable. You might end up with a mix of archetypes that only matched
/// the original query + archetypes that only match the new `QueryState`. Most of the
/// safe methods on `QueryState` call [`QueryState::update_archetypes`] internally, so
/// this is best used through a `Query`.
///
/// ## Performance
///
/// This will have similar performance as constructing a new `QueryState` since much of internal state
/// needs to be reconstructed. But it will be a little faster as it only needs to compare the intersection
/// of matching archetypes rather than iterating over all archetypes.
///
/// ## Panics
///
/// Will panic if `NewD` contains accesses not in `Q` or `OtherQ`.
pub fn join<'a, OtherD: QueryData, NewD: QueryData>(
&self,
world: impl Into<UnsafeWorldCell<'a>>,
other: &QueryState<OtherD>,
) -> QueryState<NewD, ()> {
self.join_filtered::<_, (), NewD, ()>(world, other)
}
/// Use this to combine two queries. The data accessed will be the intersection
/// of archetypes included in both queries.
///
/// ## Panics
///
/// Will panic if `NewD` or `NewF` requires accesses not in `Q` or `OtherQ`.
pub fn join_filtered<
'a,
OtherD: QueryData,
OtherF: QueryFilter,
NewD: QueryData,
NewF: QueryFilter,
>(
&self,
world: impl Into<UnsafeWorldCell<'a>>,
other: &QueryState<OtherD, OtherF>,
) -> QueryState<NewD, NewF> {
if self.world_id != other.world_id {
panic!("Joining queries initialized on different worlds is not allowed.");
}
let world = world.into();
self.validate_world(world.id());
let mut component_access = FilteredAccess::default();
let mut new_fetch_state = NewD::get_state(world.components())
.expect("Could not create fetch_state, Please initialize all referenced components before transmuting.");
let new_filter_state = NewF::get_state(world.components())
.expect("Could not create filter_state, Please initialize all referenced components before transmuting.");
NewD::set_access(&mut new_fetch_state, &self.component_access);
NewD::update_component_access(&new_fetch_state, &mut component_access);
let mut new_filter_component_access = FilteredAccess::default();
NewF::update_component_access(&new_filter_state, &mut new_filter_component_access);
component_access.extend(&new_filter_component_access);
let mut joined_component_access = self.component_access.clone();
joined_component_access.extend(&other.component_access);
assert!(
component_access.is_subset(&joined_component_access),
"Joined state for {} attempts to access terms that are not allowed by state {} joined with {}.",
core::any::type_name::<(NewD, NewF)>(), core::any::type_name::<(D, F)>(), core::any::type_name::<(OtherD, OtherF)>()
);
if self.archetype_generation != other.archetype_generation {
warn!("You have tried to join queries with different archetype_generations. This could lead to unpredictable results.");
}
// the join is dense of both the queries were dense.
let is_dense = self.is_dense && other.is_dense;
// take the intersection of the matched ids
let mut matched_tables = self.matched_tables.clone();
let mut matched_archetypes = self.matched_archetypes.clone();
matched_tables.intersect_with(&other.matched_tables);
matched_archetypes.intersect_with(&other.matched_archetypes);
let matched_storage_ids = if is_dense {
matched_tables
.ones()
.map(|id| StorageId {
table_id: TableId::from_usize(id),
})
.collect()
} else {
matched_archetypes
.ones()
.map(|id| StorageId {
archetype_id: ArchetypeId::new(id),
})
.collect()
};
QueryState {
world_id: self.world_id,
archetype_generation: self.archetype_generation,
matched_storage_ids,
is_dense,
fetch_state: new_fetch_state,
filter_state: new_filter_state,
component_access: joined_component_access,
matched_tables,
matched_archetypes,
#[cfg(feature = "trace")]
par_iter_span: tracing::info_span!(
"par_for_each",
query = core::any::type_name::<NewD>(),
filter = core::any::type_name::<NewF>(),
),
}
}
/// Gets the query result for the given [`World`] and [`Entity`].
///
/// This can only be called for read-only queries, see [`Self::get_mut`] for write-queries.
///
/// This is always guaranteed to run in `O(1)` time.
#[inline]
pub fn get<'w>(
&mut self,
world: &'w World,
entity: Entity,
) -> Result<ROQueryItem<'w, D>, QueryEntityError<'w>> {
self.update_archetypes(world);
// SAFETY: query is read only
unsafe {
self.as_readonly().get_unchecked_manual(
world.as_unsafe_world_cell_readonly(),
entity,
world.last_change_tick(),
world.read_change_tick(),
)
}
}
/// Returns the read-only query results for the given array of [`Entity`].
///
/// In case of a nonexisting entity or mismatched component, a [`QueryEntityError`] is
/// returned instead.
///
/// Note that the unlike [`QueryState::get_many_mut`], the entities passed in do not need to be unique.
///
/// # Examples
///
/// ```
/// use bevy_ecs::prelude::*;
/// use bevy_ecs::query::QueryEntityError;
///
/// #[derive(Component, PartialEq, Debug)]
/// struct A(usize);
///
/// let mut world = World::new();
/// let entity_vec: Vec<Entity> = (0..3).map(|i|world.spawn(A(i)).id()).collect();
/// let entities: [Entity; 3] = entity_vec.try_into().unwrap();
///
/// world.spawn(A(73));