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Fix safety invariants for WorldQuery::fetch and simplify cloning #8246

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merged 16 commits into from
Jul 25, 2023
Merged

Fix safety invariants for WorldQuery::fetch and simplify cloning #8246

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ee6be94
require `WorldQuery::fetch` to not alias
JoJoJet Mar 28, 2023
b022837
remove `clone_fetch`
JoJoJet Mar 28, 2023
03a59d8
derive `Clone` for tick filters
JoJoJet Mar 28, 2023
7fef544
remove a space
JoJoJet Mar 28, 2023
7616798
make it safe to clone `QueryIterationCursor`
JoJoJet Mar 28, 2023
0b4ca11
use `Copy` to implement `Clone`
JoJoJet Mar 29, 2023
942c3f2
Update crates/bevy_ecs/src/query/fetch.rs
JoJoJet Mar 29, 2023
6747653
Update crates/bevy_ecs/src/query/fetch.rs
JoJoJet Mar 29, 2023
131b0cc
Merge remote-tracking branch 'upstream/main' into world-query-safety
JoJoJet Mar 30, 2023
2f2c74f
remove an unnecessary marker field
JoJoJet Mar 30, 2023
50c4901
remove an unused import
JoJoJet Mar 30, 2023
4f2446a
Merge remote-tracking branch 'upstream/main' into world-query-safety
JoJoJet Apr 3, 2023
b54ebdf
fix a merge conflict
JoJoJet Apr 3, 2023
4cd4de2
Merge remote-tracking branch 'upstream/main' into world-query-safety
JoJoJet Apr 4, 2023
144bf17
tweak phrasing for the documentation
JoJoJet May 31, 2023
07ad079
Merge remote-tracking branch 'upstream/main' into world-query-safety
JoJoJet Jul 23, 2023
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21 changes: 10 additions & 11 deletions crates/bevy_ecs/macros/src/fetch.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -237,6 +237,16 @@ pub fn derive_world_query_impl(input: TokenStream) -> TokenStream {
#marker_name: &'__w (),
}

impl #user_impl_generics_with_world Clone for #fetch_struct_name #user_ty_generics_with_world
#user_where_clauses_with_world {
fn clone(&self) -> Self {
Self {
#(#named_field_idents: self.#named_field_idents.clone(),)*
#marker_name: &(),
}
}
}

// SAFETY: `update_component_access` and `update_archetype_component_access` are called on every field
unsafe impl #user_impl_generics #path::query::WorldQuery
for #struct_name #user_ty_generics #user_where_clauses {
Expand Down Expand Up @@ -275,17 +285,6 @@ pub fn derive_world_query_impl(input: TokenStream) -> TokenStream {
}
}

unsafe fn clone_fetch<'__w>(
_fetch: &<Self as #path::query::WorldQuery>::Fetch<'__w>
) -> <Self as #path::query::WorldQuery>::Fetch<'__w> {
#fetch_struct_name {
#(
#named_field_idents: <#field_types>::clone_fetch(& _fetch. #named_field_idents),
)*
#marker_name: &(),
}
}

const IS_DENSE: bool = true #(&& <#field_types>::IS_DENSE)*;

const IS_ARCHETYPAL: bool = true #(&& <#field_types>::IS_ARCHETYPAL)*;
Expand Down
104 changes: 35 additions & 69 deletions crates/bevy_ecs/src/query/fetch.rs
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -318,7 +318,7 @@ pub unsafe trait WorldQuery {
type Item<'a>;

/// Per archetype/table state used by this [`WorldQuery`] to fetch [`Self::Item`](crate::query::WorldQuery::Item)
type Fetch<'a>;
type Fetch<'a>: Clone;

/// The read-only variant of this [`WorldQuery`], which satisfies the [`ReadOnlyWorldQuery`] trait.
type ReadOnly: ReadOnlyWorldQuery<State = Self::State>;
Expand All @@ -345,14 +345,6 @@ pub unsafe trait WorldQuery {
this_run: Tick,
) -> Self::Fetch<'w>;

/// While this function can be called for any query, it is always safe to call if `Self: ReadOnlyWorldQuery` holds.
///
/// # Safety
/// While calling this method on its own cannot cause UB it is marked `unsafe` as the caller must ensure
/// that the returned value is not used in any way that would cause two `QueryItem<Self>` for the same
/// `archetype_row` or `table_row` to be alive at the same time.
unsafe fn clone_fetch<'w>(fetch: &Self::Fetch<'w>) -> Self::Fetch<'w>;

/// Returns true if (and only if) every table of every archetype matched by this fetch contains
/// all of the matched components. This is used to select a more efficient "table iterator"
/// for "dense" queries. If this returns true, [`WorldQuery::set_table`] must be used before
Expand Down Expand Up @@ -404,6 +396,10 @@ pub unsafe trait WorldQuery {
///
/// 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.
///
/// If `update_component_access` includes any mutable accesses, then the caller must ensure
/// that `fetch` is called no more than once for each `entity`/`table_row` in each archetype.
/// If `Self` implements [`ReadOnlyWorldQuery`], then this can safely be called multiple times.
unsafe fn fetch<'w>(
fetch: &mut Self::Fetch<'w>,
entity: Entity,
Expand Down Expand Up @@ -483,8 +479,6 @@ unsafe impl WorldQuery for Entity {
) -> Self::Fetch<'w> {
}

unsafe fn clone_fetch<'w>(_fetch: &Self::Fetch<'w>) -> Self::Fetch<'w> {}

#[inline]
unsafe fn set_archetype<'w>(
_fetch: &mut Self::Fetch<'w>,
Expand Down Expand Up @@ -554,10 +548,6 @@ unsafe impl<'a> WorldQuery for EntityRef<'a> {
world.world()
}

unsafe fn clone_fetch<'w>(world: &Self::Fetch<'w>) -> Self::Fetch<'w> {
world
}

#[inline]
unsafe fn set_archetype<'w>(
_fetch: &mut Self::Fetch<'w>,
Expand Down Expand Up @@ -620,6 +610,13 @@ pub struct ReadFetch<'w, T> {
sparse_set: Option<&'w ComponentSparseSet>,
}

impl<T> Clone for ReadFetch<'_, T> {
fn clone(&self) -> Self {
*self
}
}
impl<T> Copy for ReadFetch<'_, T> {}

/// SAFETY: `Self` is the same as `Self::ReadOnly`
unsafe impl<T: Component> WorldQuery for &T {
type Fetch<'w> = ReadFetch<'w, T>;
Expand Down Expand Up @@ -663,13 +660,6 @@ unsafe impl<T: Component> WorldQuery for &T {
}
}

unsafe fn clone_fetch<'w>(fetch: &Self::Fetch<'w>) -> Self::Fetch<'w> {
ReadFetch {
table_components: fetch.table_components,
sparse_set: fetch.sparse_set,
}
}

#[inline]
unsafe fn set_archetype<'w>(
fetch: &mut ReadFetch<'w, T>,
Expand Down Expand Up @@ -770,6 +760,13 @@ pub struct RefFetch<'w, T> {
this_run: Tick,
}

impl<T> Clone for RefFetch<'_, T> {
fn clone(&self) -> Self {
*self
}
}
impl<T> Copy for RefFetch<'_, T> {}

/// SAFETY: `Self` is the same as `Self::ReadOnly`
unsafe impl<'__w, T: Component> WorldQuery for Ref<'__w, T> {
type Fetch<'w> = RefFetch<'w, T>;
Expand Down Expand Up @@ -812,15 +809,6 @@ unsafe impl<'__w, T: Component> WorldQuery for Ref<'__w, T> {
}
}

unsafe fn clone_fetch<'w>(fetch: &Self::Fetch<'w>) -> Self::Fetch<'w> {
RefFetch {
table_data: fetch.table_data,
sparse_set: fetch.sparse_set,
last_run: fetch.last_run,
this_run: fetch.this_run,
}
}

#[inline]
unsafe fn set_archetype<'w>(
fetch: &mut RefFetch<'w, T>,
Expand Down Expand Up @@ -933,6 +921,13 @@ pub struct WriteFetch<'w, T> {
this_run: Tick,
}

impl<T> Clone for WriteFetch<'_, T> {
fn clone(&self) -> Self {
*self
}
}
impl<T> Copy for WriteFetch<'_, T> {}

/// SAFETY: access of `&T` is a subset of `&mut T`
unsafe impl<'__w, T: Component> WorldQuery for &'__w mut T {
type Fetch<'w> = WriteFetch<'w, T>;
Expand Down Expand Up @@ -975,15 +970,6 @@ unsafe impl<'__w, T: Component> WorldQuery for &'__w mut T {
}
}

unsafe fn clone_fetch<'w>(fetch: &Self::Fetch<'w>) -> Self::Fetch<'w> {
WriteFetch {
table_data: fetch.table_data,
sparse_set: fetch.sparse_set,
last_run: fetch.last_run,
this_run: fetch.this_run,
}
}

#[inline]
unsafe fn set_archetype<'w>(
fetch: &mut WriteFetch<'w, T>,
Expand Down Expand Up @@ -1084,6 +1070,15 @@ pub struct OptionFetch<'w, T: WorldQuery> {
matches: bool,
}

impl<T: WorldQuery> Clone for OptionFetch<'_, T> {
fn clone(&self) -> Self {
Self {
fetch: self.fetch.clone(),
matches: self.matches,
}
}
}

// SAFETY: defers to soundness of `T: WorldQuery` impl
unsafe impl<T: WorldQuery> WorldQuery for Option<T> {
type Fetch<'w> = OptionFetch<'w, T>;
Expand Down Expand Up @@ -1112,13 +1107,6 @@ unsafe impl<T: WorldQuery> WorldQuery for Option<T> {
}
}

unsafe fn clone_fetch<'w>(fetch: &Self::Fetch<'w>) -> Self::Fetch<'w> {
OptionFetch {
fetch: T::clone_fetch(&fetch.fetch),
matches: fetch.matches,
}
}

#[inline]
unsafe fn set_archetype<'w>(
fetch: &mut OptionFetch<'w, T>,
Expand Down Expand Up @@ -1271,10 +1259,6 @@ unsafe impl<T: Component> WorldQuery for Has<T> {
false
}

unsafe fn clone_fetch<'w>(fetch: &Self::Fetch<'w>) -> Self::Fetch<'w> {
*fetch
}

#[inline]
unsafe fn set_archetype<'w>(
fetch: &mut Self::Fetch<'w>,
Expand Down Expand Up @@ -1351,13 +1335,6 @@ macro_rules! impl_tuple_fetch {
($($name::init_fetch(_world, $name, _last_run, _this_run),)*)
}

unsafe fn clone_fetch<'w>(
fetch: &Self::Fetch<'w>,
) -> Self::Fetch<'w> {
let ($($name,)*) = &fetch;
($($name::clone_fetch($name),)*)
}

const IS_DENSE: bool = true $(&& $name::IS_DENSE)*;

const IS_ARCHETYPAL: bool = true $(&& $name::IS_ARCHETYPAL)*;
Expand Down Expand Up @@ -1461,13 +1438,6 @@ macro_rules! impl_anytuple_fetch {
($(($name::init_fetch(_world, $name, _last_run, _this_run), false),)*)
}

unsafe fn clone_fetch<'w>(
fetch: &Self::Fetch<'w>,
) -> Self::Fetch<'w> {
let ($($name,)*) = &fetch;
($(($name::clone_fetch(& $name.0), $name.1),)*)
}

const IS_DENSE: bool = true $(&& $name::IS_DENSE)*;

const IS_ARCHETYPAL: bool = true $(&& $name::IS_ARCHETYPAL)*;
Expand Down Expand Up @@ -1588,8 +1558,6 @@ unsafe impl<Q: WorldQuery> WorldQuery for NopWorldQuery<Q> {
) {
}

unsafe fn clone_fetch<'w>(_fetch: &Self::Fetch<'w>) -> Self::Fetch<'w> {}

#[inline(always)]
unsafe fn set_archetype(
_fetch: &mut (),
Expand Down Expand Up @@ -1651,8 +1619,6 @@ unsafe impl<T: ?Sized> WorldQuery for PhantomData<T> {
) -> Self::Fetch<'w> {
}

unsafe fn clone_fetch<'w>(_fetch: &Self::Fetch<'w>) -> Self::Fetch<'w> {}

// `PhantomData` does not match any components, so all components it matches
// are stored in a Table (vacuous truth).
const IS_DENSE: bool = true;
Expand Down
46 changes: 13 additions & 33 deletions crates/bevy_ecs/src/query/filter.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -59,8 +59,6 @@ unsafe impl<T: Component> WorldQuery for With<T> {
) {
}

unsafe fn clone_fetch<'w>(_fetch: &Self::Fetch<'w>) -> Self::Fetch<'w> {}

const IS_DENSE: bool = {
match T::Storage::STORAGE_TYPE {
StorageType::Table => true,
Expand Down Expand Up @@ -162,8 +160,6 @@ unsafe impl<T: Component> WorldQuery for Without<T> {
) {
}

unsafe fn clone_fetch<'w>(_fetch: &Self::Fetch<'w>) -> Self::Fetch<'w> {}

const IS_DENSE: bool = {
match T::Storage::STORAGE_TYPE {
StorageType::Table => true,
Expand Down Expand Up @@ -259,6 +255,15 @@ pub struct OrFetch<'w, T: WorldQuery> {
matches: bool,
}

impl<T: WorldQuery> Clone for OrFetch<'_, T> {
fn clone(&self) -> Self {
Self {
fetch: self.fetch.clone(),
matches: self.matches,
}
}
}

macro_rules! impl_query_filter_tuple {
($(($filter: ident, $state: ident)),*) => {
#[allow(unused_variables)]
Expand Down Expand Up @@ -288,18 +293,6 @@ macro_rules! impl_query_filter_tuple {
},)*)
}

unsafe fn clone_fetch<'w>(
fetch: &Self::Fetch<'w>,
) -> Self::Fetch<'w> {
let ($($filter,)*) = &fetch;
($(
OrFetch {
fetch: $filter::clone_fetch(&$filter.fetch),
matches: $filter.matches,
},
)*)
}

#[inline]
unsafe fn set_table<'w>(fetch: &mut Self::Fetch<'w>, state: &Self::State, table: &'w Table) {
let ($($filter,)*) = fetch;
Expand Down Expand Up @@ -403,18 +396,18 @@ macro_rules! impl_tick_filter {
pub struct $name<T>(PhantomData<T>);

#[doc(hidden)]
#[derive(Clone)]
$(#[$fetch_meta])*
pub struct $fetch_name<'w, T> {
table_ticks: Option< ThinSlicePtr<'w, UnsafeCell<Tick>>>,
marker: PhantomData<T>,
pub struct $fetch_name<'w> {
table_ticks: Option<ThinSlicePtr<'w, UnsafeCell<Tick>>>,
sparse_set: Option<&'w ComponentSparseSet>,
last_run: Tick,
this_run: Tick,
}

// SAFETY: `Self::ReadOnly` is the same as `Self`
unsafe impl<T: Component> WorldQuery for $name<T> {
type Fetch<'w> = $fetch_name<'w, T>;
type Fetch<'w> = $fetch_name<'w>;
type Item<'w> = bool;
type ReadOnly = Self;
type State = ComponentId;
Expand All @@ -440,24 +433,11 @@ macro_rules! impl_tick_filter {
.get(id)
.debug_checked_unwrap()
}),
marker: PhantomData,
last_run,
this_run,
}
}

unsafe fn clone_fetch<'w>(
fetch: &Self::Fetch<'w>,
) -> Self::Fetch<'w> {
$fetch_name {
table_ticks: fetch.table_ticks,
sparse_set: fetch.sparse_set,
last_run: fetch.last_run,
this_run: fetch.this_run,
marker: PhantomData,
}
}

const IS_DENSE: bool = {
match T::Storage::STORAGE_TYPE {
StorageType::Table => true,
Expand Down
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