bevy/crates/bevy_ecs/src/query/iter.rs
eri 5f8f3b532c
Check cfg during CI and fix feature typos (#12103)
# Objective

- Add the new `-Zcheck-cfg` checks to catch more warnings
- Fixes #12091

## Solution

- Create a new `cfg-check` to the CI that runs `cargo check -Zcheck-cfg
--workspace` using cargo nightly (and fails if there are warnings)
- Fix all warnings generated by the new check

---

## Changelog

- Remove all redundant imports
- Fix cfg wasm32 targets
- Add 3 dead code exceptions (should StandardColor be unused?)
- Convert ios_simulator to a feature (I'm not sure if this is the right
way to do it, but the check complained before)

## Migration Guide

No breaking changes

---------

Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
2024-02-25 15:19:27 +00:00

868 lines
33 KiB
Rust

use crate::{
archetype::{Archetype, ArchetypeEntity, ArchetypeId, Archetypes},
component::Tick,
entity::{Entities, Entity},
query::{ArchetypeFilter, DebugCheckedUnwrap, QueryState},
storage::{Table, TableId, TableRow, Tables},
world::unsafe_world_cell::UnsafeWorldCell,
};
use std::{borrow::Borrow, iter::FusedIterator, mem::MaybeUninit, ops::Range};
use super::{QueryData, QueryFilter, ReadOnlyQueryData};
/// An [`Iterator`] over query results of a [`Query`](crate::system::Query).
///
/// This struct is created by the [`Query::iter`](crate::system::Query::iter) and
/// [`Query::iter_mut`](crate::system::Query::iter_mut) methods.
pub struct QueryIter<'w, 's, D: QueryData, F: QueryFilter> {
tables: &'w Tables,
archetypes: &'w Archetypes,
query_state: &'s QueryState<D, F>,
cursor: QueryIterationCursor<'w, 's, D, F>,
}
impl<'w, 's, D: QueryData, F: QueryFilter> QueryIter<'w, 's, D, F> {
/// # Safety
/// - `world` must have permission to access any of the components registered in `query_state`.
/// - `world` must be the same one used to initialize `query_state`.
pub(crate) unsafe fn new(
world: UnsafeWorldCell<'w>,
query_state: &'s QueryState<D, F>,
last_run: Tick,
this_run: Tick,
) -> Self {
QueryIter {
query_state,
// SAFETY: We only access table data that has been registered in `query_state`.
tables: unsafe { &world.storages().tables },
archetypes: world.archetypes(),
// SAFETY: The invariants are uphold by the caller.
cursor: unsafe { QueryIterationCursor::init(world, query_state, last_run, this_run) },
}
}
/// Executes the equivalent of [`Iterator::for_each`] over a contiguous segment
/// from an table.
///
/// # Safety
/// - all `rows` must be in `[0, table.entity_count)`.
/// - `table` must match D and F
/// - Both `D::IS_DENSE` and `F::IS_DENSE` must be true.
#[inline]
#[cfg(all(not(target_arch = "wasm32"), feature = "multi-threaded"))]
pub(super) unsafe fn for_each_in_table_range<Func>(
&mut self,
func: &mut Func,
table: &'w Table,
rows: Range<usize>,
) where
Func: FnMut(D::Item<'w>),
{
// SAFETY: Caller assures that D::IS_DENSE and F::IS_DENSE are true, that table matches D and F
// and all indices in rows are in range.
unsafe {
self.fold_over_table_range((), &mut |_, item| func(item), table, rows);
}
}
/// Executes the equivalent of [`Iterator::for_each`] over a contiguous segment
/// from an archetype.
///
/// # Safety
/// - all `indices` must be in `[0, archetype.len())`.
/// - `archetype` must match D and F
/// - Either `D::IS_DENSE` or `F::IS_DENSE` must be false.
#[inline]
#[cfg(all(not(target_arch = "wasm32"), feature = "multi-threaded"))]
pub(super) unsafe fn for_each_in_archetype_range<Func>(
&mut self,
func: &mut Func,
archetype: &'w Archetype,
rows: Range<usize>,
) where
Func: FnMut(D::Item<'w>),
{
// SAFETY: Caller assures that either D::IS_DENSE or F::IS_DENSE are false, that archetype matches D and F
// and all indices in rows are in range.
unsafe {
self.fold_over_archetype_range((), &mut |_, item| func(item), archetype, rows);
}
}
/// Executes the equivalent of [`Iterator::fold`] over a contiguous segment
/// from an table.
///
/// # Safety
/// - all `rows` must be in `[0, table.entity_count)`.
/// - `table` must match D and F
/// - Both `D::IS_DENSE` and `F::IS_DENSE` must be true.
#[inline]
pub(super) unsafe fn fold_over_table_range<B, Func>(
&mut self,
mut accum: B,
func: &mut Func,
table: &'w Table,
rows: Range<usize>,
) -> B
where
Func: FnMut(B, D::Item<'w>) -> B,
{
assert!(
rows.end <= u32::MAX as usize,
"TableRow is only valid up to u32::MAX"
);
D::set_table(&mut self.cursor.fetch, &self.query_state.fetch_state, table);
F::set_table(
&mut self.cursor.filter,
&self.query_state.filter_state,
table,
);
let entities = table.entities();
for row in rows {
// SAFETY: Caller assures `row` in range of the current archetype.
let entity = unsafe { entities.get_unchecked(row) };
let row = TableRow::from_usize(row);
// SAFETY: set_table was called prior.
// Caller assures `row` in range of the current archetype.
let fetched = unsafe { !F::filter_fetch(&mut self.cursor.filter, *entity, row) };
if fetched {
continue;
}
// SAFETY: set_table was called prior.
// Caller assures `row` in range of the current archetype.
let item = D::fetch(&mut self.cursor.fetch, *entity, row);
accum = func(accum, item);
}
accum
}
/// Executes the equivalent of [`Iterator::fold`] over a contiguous segment
/// from an archetype.
///
/// # Safety
/// - all `indices` must be in `[0, archetype.len())`.
/// - `archetype` must match D and F
/// - Either `D::IS_DENSE` or `F::IS_DENSE` must be false.
#[inline]
pub(super) unsafe fn fold_over_archetype_range<B, Func>(
&mut self,
mut accum: B,
func: &mut Func,
archetype: &'w Archetype,
indices: Range<usize>,
) -> B
where
Func: FnMut(B, D::Item<'w>) -> B,
{
let table = self.tables.get(archetype.table_id()).debug_checked_unwrap();
D::set_archetype(
&mut self.cursor.fetch,
&self.query_state.fetch_state,
archetype,
table,
);
F::set_archetype(
&mut self.cursor.filter,
&self.query_state.filter_state,
archetype,
table,
);
let entities = archetype.entities();
for index in indices {
// SAFETY: Caller assures `index` in range of the current archetype.
let archetype_entity = unsafe { entities.get_unchecked(index) };
// SAFETY: set_archetype was called prior.
// Caller assures `index` in range of the current archetype.
let fetched = unsafe {
!F::filter_fetch(
&mut self.cursor.filter,
archetype_entity.id(),
archetype_entity.table_row(),
)
};
if fetched {
continue;
}
// SAFETY: set_archetype was called prior, `index` is an archetype index in range of the current archetype
// Caller assures `index` in range of the current archetype.
let item = unsafe {
D::fetch(
&mut self.cursor.fetch,
archetype_entity.id(),
archetype_entity.table_row(),
)
};
accum = func(accum, item);
}
accum
}
}
impl<'w, 's, D: QueryData, F: QueryFilter> Iterator for QueryIter<'w, 's, D, F> {
type Item = D::Item<'w>;
#[inline(always)]
fn next(&mut self) -> Option<Self::Item> {
// SAFETY:
// `tables` and `archetypes` belong to the same world that the cursor was initialized for.
// `query_state` is the state that was passed to `QueryIterationCursor::init`.
unsafe {
self.cursor
.next(self.tables, self.archetypes, self.query_state)
}
}
fn size_hint(&self) -> (usize, Option<usize>) {
let max_size = self.cursor.max_remaining(self.tables, self.archetypes);
let archetype_query = F::IS_ARCHETYPAL;
let min_size = if archetype_query { max_size } else { 0 };
(min_size, Some(max_size))
}
#[inline]
fn fold<B, Func>(mut self, init: B, mut func: Func) -> B
where
Func: FnMut(B, Self::Item) -> B,
{
let mut accum = init;
// Empty any remaining uniterated values from the current table/archetype
while self.cursor.current_row != self.cursor.current_len {
let Some(item) = self.next() else { break };
accum = func(accum, item);
}
if D::IS_DENSE && F::IS_DENSE {
for table_id in self.cursor.table_id_iter.clone() {
// SAFETY: Matched table IDs are guaranteed to still exist.
let table = unsafe { self.tables.get(*table_id).debug_checked_unwrap() };
accum =
// SAFETY:
// - The fetched table matches both D and F
// - The provided range is equivalent to [0, table.entity_count)
// - The if block ensures that D::IS_DENSE and F::IS_DENSE are both true
unsafe { self.fold_over_table_range(accum, &mut func, table, 0..table.entity_count()) };
}
} else {
for archetype_id in self.cursor.archetype_id_iter.clone() {
let archetype =
// SAFETY: Matched archetype IDs are guaranteed to still exist.
unsafe { self.archetypes.get(*archetype_id).debug_checked_unwrap() };
accum =
// SAFETY:
// - The fetched archetype matches both D and F
// - The provided range is equivalent to [0, archetype.len)
// - The if block ensures that ether D::IS_DENSE or F::IS_DENSE are false
unsafe { self.fold_over_archetype_range(accum, &mut func, archetype, 0..archetype.len()) };
}
}
accum
}
}
// This is correct as [`QueryIter`] always returns `None` once exhausted.
impl<'w, 's, D: QueryData, F: QueryFilter> FusedIterator for QueryIter<'w, 's, D, F> {}
/// An [`Iterator`] over the query items generated from an iterator of [`Entity`]s.
///
/// Items are returned in the order of the provided iterator.
/// Entities that don't match the query are skipped.
///
/// This struct is created by the [`Query::iter_many`](crate::system::Query::iter_many) and [`Query::iter_many_mut`](crate::system::Query::iter_many_mut) methods.
pub struct QueryManyIter<'w, 's, D: QueryData, F: QueryFilter, I: Iterator>
where
I::Item: Borrow<Entity>,
{
entity_iter: I,
entities: &'w Entities,
tables: &'w Tables,
archetypes: &'w Archetypes,
fetch: D::Fetch<'w>,
filter: F::Fetch<'w>,
query_state: &'s QueryState<D, F>,
}
impl<'w, 's, D: QueryData, F: QueryFilter, I: Iterator> QueryManyIter<'w, 's, D, F, I>
where
I::Item: Borrow<Entity>,
{
/// # Safety
/// - `world` must have permission to access any of the components registered in `query_state`.
/// - `world` must be the same one used to initialize `query_state`.
pub(crate) unsafe fn new<EntityList: IntoIterator<IntoIter = I>>(
world: UnsafeWorldCell<'w>,
query_state: &'s QueryState<D, F>,
entity_list: EntityList,
last_run: Tick,
this_run: Tick,
) -> QueryManyIter<'w, 's, D, F, I> {
let fetch = D::init_fetch(world, &query_state.fetch_state, last_run, this_run);
let filter = F::init_fetch(world, &query_state.filter_state, last_run, this_run);
QueryManyIter {
query_state,
entities: world.entities(),
archetypes: world.archetypes(),
// SAFETY: We only access table data that has been registered in `query_state`.
// This means `world` has permission to access the data we use.
tables: &world.storages().tables,
fetch,
filter,
entity_iter: entity_list.into_iter(),
}
}
/// Safety:
/// The lifetime here is not restrictive enough for Fetch with &mut access,
/// as calling `fetch_next_aliased_unchecked` multiple times can produce multiple
/// references to the same component, leading to unique reference aliasing.
///
/// It is always safe for shared access.
#[inline(always)]
unsafe fn fetch_next_aliased_unchecked(&mut self) -> Option<D::Item<'w>> {
for entity in self.entity_iter.by_ref() {
let entity = *entity.borrow();
let Some(location) = self.entities.get(entity) else {
continue;
};
if !self
.query_state
.matched_archetypes
.contains(location.archetype_id.index())
{
continue;
}
let archetype = self
.archetypes
.get(location.archetype_id)
.debug_checked_unwrap();
let table = self.tables.get(location.table_id).debug_checked_unwrap();
// SAFETY: `archetype` is from the world that `fetch/filter` were created for,
// `fetch_state`/`filter_state` are the states that `fetch/filter` were initialized with
unsafe {
D::set_archetype(
&mut self.fetch,
&self.query_state.fetch_state,
archetype,
table,
);
}
// SAFETY: `table` is from the world that `fetch/filter` were created for,
// `fetch_state`/`filter_state` are the states that `fetch/filter` were initialized with
unsafe {
F::set_archetype(
&mut self.filter,
&self.query_state.filter_state,
archetype,
table,
);
}
// SAFETY: set_archetype was called prior.
// `location.archetype_row` is an archetype index row in range of the current archetype, because if it was not, the match above would have `continue`d
if unsafe { F::filter_fetch(&mut self.filter, entity, location.table_row) } {
// SAFETY:
// - set_archetype was called prior, `location.archetype_row` is an archetype index in range of the current archetype
// - fetch is only called once for each entity.
return Some(unsafe { D::fetch(&mut self.fetch, entity, location.table_row) });
}
}
None
}
/// Get next result from the query
#[inline(always)]
pub fn fetch_next(&mut self) -> Option<D::Item<'_>> {
// SAFETY: we are limiting the returned reference to self,
// making sure this method cannot be called multiple times without getting rid
// of any previously returned unique references first, thus preventing aliasing.
unsafe { self.fetch_next_aliased_unchecked().map(D::shrink) }
}
}
impl<'w, 's, D: ReadOnlyQueryData, F: QueryFilter, I: Iterator> Iterator
for QueryManyIter<'w, 's, D, F, I>
where
I::Item: Borrow<Entity>,
{
type Item = D::Item<'w>;
#[inline(always)]
fn next(&mut self) -> Option<Self::Item> {
// SAFETY: It is safe to alias for ReadOnlyWorldQuery.
unsafe { self.fetch_next_aliased_unchecked() }
}
fn size_hint(&self) -> (usize, Option<usize>) {
let (_, max_size) = self.entity_iter.size_hint();
(0, max_size)
}
}
// This is correct as [`QueryManyIter`] always returns `None` once exhausted.
impl<'w, 's, D: ReadOnlyQueryData, F: QueryFilter, I: Iterator> FusedIterator
for QueryManyIter<'w, 's, D, F, I>
where
I::Item: Borrow<Entity>,
{
}
/// An iterator over `K`-sized combinations of query items without repetition.
///
/// A combination is an arrangement of a collection of items where order does not matter.
///
/// `K` is the number of items that make up each subset, and the number of items returned by the iterator.
/// `N` is the number of total entities output by the query.
///
/// For example, given the list [1, 2, 3, 4], where `K` is 2, the combinations without repeats are
/// [1, 2], [1, 3], [1, 4], [2, 3], [2, 4], [3, 4].
/// And in this case, `N` would be defined as 4 since the size of the input list is 4.
///
/// The number of combinations depend on how `K` relates to the number of entities matching the [`Query`]:
/// - if `K = N`, only one combination exists,
/// - if `K < N`, there are <sub>N</sub>C<sub>K</sub> combinations (see the [performance section] of `Query`),
/// - if `K > N`, there are no combinations.
///
/// The output combination is not guaranteed to have any order of iteration.
///
/// # Usage
///
/// This type is returned by calling [`Query::iter_combinations`] or [`Query::iter_combinations_mut`].
///
/// It implements [`Iterator`] only if it iterates over read-only query items ([learn more]).
///
/// In the case of mutable query items, it can be iterated by calling [`fetch_next`] in a `while let` loop.
///
/// # Examples
///
/// The following example shows how to traverse the iterator when the query items are read-only.
///
/// ```
/// # use bevy_ecs::prelude::*;
/// # #[derive(Component)]
/// # struct ComponentA;
/// #
/// fn some_system(query: Query<&ComponentA>) {
/// for [a1, a2] in query.iter_combinations() {
/// // ...
/// }
/// }
/// ```
///
/// The following example shows how `fetch_next` should be called with a `while let` loop to traverse the iterator when the query items are mutable.
///
/// ```
/// # use bevy_ecs::prelude::*;
/// # #[derive(Component)]
/// # struct ComponentA;
/// #
/// fn some_system(mut query: Query<&mut ComponentA>) {
/// let mut combinations = query.iter_combinations_mut();
/// while let Some([a1, a2]) = combinations.fetch_next() {
/// // ...
/// }
/// }
/// ```
///
/// [`fetch_next`]: Self::fetch_next
/// [learn more]: Self#impl-Iterator
/// [performance section]: crate::system::Query#performance
/// [`Query`]: crate::system::Query
/// [`Query::iter_combinations`]: crate::system::Query::iter_combinations
/// [`Query::iter_combinations_mut`]: crate::system::Query::iter_combinations_mut
pub struct QueryCombinationIter<'w, 's, D: QueryData, F: QueryFilter, const K: usize> {
tables: &'w Tables,
archetypes: &'w Archetypes,
query_state: &'s QueryState<D, F>,
cursors: [QueryIterationCursor<'w, 's, D, F>; K],
}
impl<'w, 's, D: QueryData, F: QueryFilter, const K: usize> QueryCombinationIter<'w, 's, D, F, K> {
/// # Safety
/// - `world` must have permission to access any of the components registered in `query_state`.
/// - `world` must be the same one used to initialize `query_state`.
pub(crate) unsafe fn new(
world: UnsafeWorldCell<'w>,
query_state: &'s QueryState<D, F>,
last_run: Tick,
this_run: Tick,
) -> Self {
// Initialize array with cursors.
// There is no FromIterator on arrays, so instead initialize it manually with MaybeUninit
let mut array: MaybeUninit<[QueryIterationCursor<'w, 's, D, F>; K]> = MaybeUninit::uninit();
let ptr = array
.as_mut_ptr()
.cast::<QueryIterationCursor<'w, 's, D, F>>();
if K != 0 {
ptr.write(QueryIterationCursor::init(
world,
query_state,
last_run,
this_run,
));
}
for slot in (1..K).map(|offset| ptr.add(offset)) {
slot.write(QueryIterationCursor::init_empty(
world,
query_state,
last_run,
this_run,
));
}
QueryCombinationIter {
query_state,
// SAFETY: We only access table data that has been registered in `query_state`.
tables: unsafe { &world.storages().tables },
archetypes: world.archetypes(),
cursors: array.assume_init(),
}
}
/// Safety:
/// The lifetime here is not restrictive enough for Fetch with &mut access,
/// as calling `fetch_next_aliased_unchecked` multiple times can produce multiple
/// references to the same component, leading to unique reference aliasing.
///.
/// It is always safe for shared access.
unsafe fn fetch_next_aliased_unchecked(&mut self) -> Option<[D::Item<'w>; K]> {
if K == 0 {
return None;
}
// PERF: can speed up the following code using `cursor.remaining()` instead of `next_item.is_none()`
// when D::IS_ARCHETYPAL && F::IS_ARCHETYPAL
//
// let `i` be the index of `c`, the last cursor in `self.cursors` that
// returns `K-i` or more elements.
// Make cursor in index `j` for all `j` in `[i, K)` a copy of `c` advanced `j-i+1` times.
// If no such `c` exists, return `None`
'outer: for i in (0..K).rev() {
match self.cursors[i].next(self.tables, self.archetypes, self.query_state) {
Some(_) => {
for j in (i + 1)..K {
self.cursors[j] = self.cursors[j - 1].clone();
match self.cursors[j].next(self.tables, self.archetypes, self.query_state) {
Some(_) => {}
None if i > 0 => continue 'outer,
None => return None,
}
}
break;
}
None if i > 0 => continue,
None => return None,
}
}
let mut values = MaybeUninit::<[D::Item<'w>; K]>::uninit();
let ptr = values.as_mut_ptr().cast::<D::Item<'w>>();
for (offset, cursor) in self.cursors.iter_mut().enumerate() {
ptr.add(offset).write(cursor.peek_last().unwrap());
}
Some(values.assume_init())
}
/// Get next combination of queried components
#[inline]
pub fn fetch_next(&mut self) -> Option<[D::Item<'_>; K]> {
// SAFETY: we are limiting the returned reference to self,
// making sure this method cannot be called multiple times without getting rid
// of any previously returned unique references first, thus preventing aliasing.
unsafe {
self.fetch_next_aliased_unchecked()
.map(|array| array.map(D::shrink))
}
}
}
// Iterator type is intentionally implemented only for read-only access.
// Doing so for mutable references would be unsound, because calling `next`
// multiple times would allow multiple owned references to the same data to exist.
impl<'w, 's, D: ReadOnlyQueryData, F: QueryFilter, const K: usize> Iterator
for QueryCombinationIter<'w, 's, D, F, K>
{
type Item = [D::Item<'w>; K];
#[inline]
fn next(&mut self) -> Option<Self::Item> {
// Safety: it is safe to alias for ReadOnlyWorldQuery
unsafe { QueryCombinationIter::fetch_next_aliased_unchecked(self) }
}
fn size_hint(&self) -> (usize, Option<usize>) {
// binomial coefficient: (n ; k) = n! / k!(n-k)! = (n*n-1*...*n-k+1) / k!
// See https://en.wikipedia.org/wiki/Binomial_coefficient
// See https://blog.plover.com/math/choose.html for implementation
// It was chosen to reduce overflow potential.
fn choose(n: usize, k: usize) -> Option<usize> {
if k > n || n == 0 {
return Some(0);
}
let k = k.min(n - k);
let ks = 1..=k;
let ns = (n - k + 1..=n).rev();
ks.zip(ns)
.try_fold(1_usize, |acc, (k, n)| Some(acc.checked_mul(n)? / k))
}
// sum_i=0..k choose(cursors[i].remaining, k-i)
let max_combinations = self
.cursors
.iter()
.enumerate()
.try_fold(0, |acc, (i, cursor)| {
let n = cursor.max_remaining(self.tables, self.archetypes);
Some(acc + choose(n, K - i)?)
});
let archetype_query = F::IS_ARCHETYPAL;
let known_max = max_combinations.unwrap_or(usize::MAX);
let min_combinations = if archetype_query { known_max } else { 0 };
(min_combinations, max_combinations)
}
}
impl<'w, 's, D: QueryData, F: QueryFilter> ExactSizeIterator for QueryIter<'w, 's, D, F>
where
F: ArchetypeFilter,
{
fn len(&self) -> usize {
self.size_hint().0
}
}
// This is correct as [`QueryCombinationIter`] always returns `None` once exhausted.
impl<'w, 's, D: ReadOnlyQueryData, F: QueryFilter, const K: usize> FusedIterator
for QueryCombinationIter<'w, 's, D, F, K>
{
}
struct QueryIterationCursor<'w, 's, D: QueryData, F: QueryFilter> {
table_id_iter: std::slice::Iter<'s, TableId>,
archetype_id_iter: std::slice::Iter<'s, ArchetypeId>,
table_entities: &'w [Entity],
archetype_entities: &'w [ArchetypeEntity],
fetch: D::Fetch<'w>,
filter: F::Fetch<'w>,
// length of the table table or length of the archetype, depending on whether both `D`'s and `F`'s fetches are dense
current_len: usize,
// either table row or archetype index, depending on whether both `D`'s and `F`'s fetches are dense
current_row: usize,
}
impl<D: QueryData, F: QueryFilter> Clone for QueryIterationCursor<'_, '_, D, F> {
fn clone(&self) -> Self {
Self {
table_id_iter: self.table_id_iter.clone(),
archetype_id_iter: self.archetype_id_iter.clone(),
table_entities: self.table_entities,
archetype_entities: self.archetype_entities,
fetch: self.fetch.clone(),
filter: self.filter.clone(),
current_len: self.current_len,
current_row: self.current_row,
}
}
}
impl<'w, 's, D: QueryData, F: QueryFilter> QueryIterationCursor<'w, 's, D, F> {
const IS_DENSE: bool = D::IS_DENSE && F::IS_DENSE;
unsafe fn init_empty(
world: UnsafeWorldCell<'w>,
query_state: &'s QueryState<D, F>,
last_run: Tick,
this_run: Tick,
) -> Self {
QueryIterationCursor {
table_id_iter: [].iter(),
archetype_id_iter: [].iter(),
..Self::init(world, query_state, last_run, this_run)
}
}
/// # Safety
/// - `world` must have permission to access any of the components registered in `query_state`.
/// - `world` must be the same one used to initialize `query_state`.
unsafe fn init(
world: UnsafeWorldCell<'w>,
query_state: &'s QueryState<D, F>,
last_run: Tick,
this_run: Tick,
) -> Self {
let fetch = D::init_fetch(world, &query_state.fetch_state, last_run, this_run);
let filter = F::init_fetch(world, &query_state.filter_state, last_run, this_run);
QueryIterationCursor {
fetch,
filter,
table_entities: &[],
archetype_entities: &[],
table_id_iter: query_state.matched_table_ids.iter(),
archetype_id_iter: query_state.matched_archetype_ids.iter(),
current_len: 0,
current_row: 0,
}
}
/// retrieve item returned from most recent `next` call again.
#[inline]
unsafe fn peek_last(&mut self) -> Option<D::Item<'w>> {
if self.current_row > 0 {
let index = self.current_row - 1;
if Self::IS_DENSE {
let entity = self.table_entities.get_unchecked(index);
Some(D::fetch(
&mut self.fetch,
*entity,
TableRow::from_usize(index),
))
} else {
let archetype_entity = self.archetype_entities.get_unchecked(index);
Some(D::fetch(
&mut self.fetch,
archetype_entity.id(),
archetype_entity.table_row(),
))
}
} else {
None
}
}
/// How many values will this cursor return at most?
///
/// Note that if `D::IS_ARCHETYPAL && F::IS_ARCHETYPAL`, the return value
/// will be **the exact count of remaining values**.
fn max_remaining(&self, tables: &'w Tables, archetypes: &'w Archetypes) -> usize {
let remaining_matched: usize = if Self::IS_DENSE {
let ids = self.table_id_iter.clone();
ids.map(|id| tables[*id].entity_count()).sum()
} else {
let ids = self.archetype_id_iter.clone();
ids.map(|id| archetypes[*id].len()).sum()
};
remaining_matched + self.current_len - self.current_row
}
// NOTE: If you are changing query iteration code, remember to update the following places, where relevant:
// QueryIter, QueryIterationCursor, QueryManyIter, QueryCombinationIter, QueryState::par_for_each_unchecked_manual
/// # Safety
/// `tables` and `archetypes` must belong to the same world that the [`QueryIterationCursor`]
/// was initialized for.
/// `query_state` must be the same [`QueryState`] that was passed to `init` or `init_empty`.
#[inline(always)]
unsafe fn next(
&mut self,
tables: &'w Tables,
archetypes: &'w Archetypes,
query_state: &'s QueryState<D, F>,
) -> Option<D::Item<'w>> {
if Self::IS_DENSE {
loop {
// we are on the beginning of the query, or finished processing a table, so skip to the next
if self.current_row == self.current_len {
let table_id = self.table_id_iter.next()?;
let table = tables.get(*table_id).debug_checked_unwrap();
// SAFETY: `table` is from the world that `fetch/filter` were created for,
// `fetch_state`/`filter_state` are the states that `fetch/filter` were initialized with
unsafe {
D::set_table(&mut self.fetch, &query_state.fetch_state, table);
F::set_table(&mut self.filter, &query_state.filter_state, table);
}
self.table_entities = table.entities();
self.current_len = table.entity_count();
self.current_row = 0;
continue;
}
// SAFETY: set_table was called prior.
// `current_row` is a table row in range of the current table, because if it was not, then the if above would have been executed.
let entity = unsafe { self.table_entities.get_unchecked(self.current_row) };
let row = TableRow::from_usize(self.current_row);
if !F::filter_fetch(&mut self.filter, *entity, row) {
self.current_row += 1;
continue;
}
// SAFETY:
// - set_table was called prior.
// - `current_row` must be a table row in range of the current table,
// because if it was not, then the if above would have been executed.
// - fetch is only called once for each `entity`.
let item = unsafe { D::fetch(&mut self.fetch, *entity, row) };
self.current_row += 1;
return Some(item);
}
} else {
loop {
if self.current_row == self.current_len {
let archetype_id = self.archetype_id_iter.next()?;
let archetype = archetypes.get(*archetype_id).debug_checked_unwrap();
let table = tables.get(archetype.table_id()).debug_checked_unwrap();
// SAFETY: `archetype` and `tables` are from the world that `fetch/filter` were created for,
// `fetch_state`/`filter_state` are the states that `fetch/filter` were initialized with
unsafe {
D::set_archetype(
&mut self.fetch,
&query_state.fetch_state,
archetype,
table,
);
F::set_archetype(
&mut self.filter,
&query_state.filter_state,
archetype,
table,
);
}
self.archetype_entities = archetype.entities();
self.current_len = archetype.len();
self.current_row = 0;
continue;
}
// SAFETY: set_archetype was called prior.
// `current_row` is an archetype index row in range of the current archetype, because if it was not, then the if above would have been executed.
let archetype_entity =
unsafe { self.archetype_entities.get_unchecked(self.current_row) };
if !F::filter_fetch(
&mut self.filter,
archetype_entity.id(),
archetype_entity.table_row(),
) {
self.current_row += 1;
continue;
}
// SAFETY:
// - set_archetype was called prior.
// - `current_row` must be an archetype index row in range of the current archetype,
// because if it was not, then the if above would have been executed.
// - fetch is only called once for each `archetype_entity`.
let item = unsafe {
D::fetch(
&mut self.fetch,
archetype_entity.id(),
archetype_entity.table_row(),
)
};
self.current_row += 1;
return Some(item);
}
}
}
}