Struct specs::join::MaybeJoin

pub struct MaybeJoin<J>(pub J);

Returns a structure that implements Join/LendJoin/MaybeJoin if the contained T does and that yields all indices, returning None for all missing elements and Some(T) for found elements.

For usage see LendJoin::maybe().

WARNING: Do not have a join of only MaybeJoins. Otherwise the join will iterate over every single index of the bitset. If you want a join with all MaybeJoins, add an EntitiesRes to the join as well to bound the join to all entities that are alive.

Tuple Fields

0: J

Trait Implementations

impl<T> Join for MaybeJoin<T>where T: Join,

type Mask = BitSetAll

Type of joined bit mask.

type Type = Option<<T as Join>::Type>

Type of joined components.

type Value = (<T as Join>::Mask, <T as Join>::Value)

Type of joined storages.

unsafe fn open(self) -> (Self::Mask, Self::Value)

Open this join by returning the mask and the storages.

unsafe fn get((mask, value): &mut Self::Value, id: Index) -> Self::Type

Get a joined component value by a given index.

fn is_unconstrained() -> bool

If this Join typically returns all indices in the mask, then iterating over only it or combined with other joins that are also dangerous will cause the JoinIter to go through all indices which is usually not what is wanted and will kill performance.

fn join(self) -> JoinIter<Self> where Self: Sized,

Create a joined iterator over the contents.

impl<T> LendJoin for MaybeJoin<T>where T: LendJoin,

type Mask = BitSetAll

Type of joined bit mask.

type Value = (<T as LendJoin>::Mask, <T as LendJoin>::Value)

Type of joined storages.

unsafe fn open(self) -> (Self::Mask, Self::Value)

Open this join by returning the mask and the storages.

unsafe fn get<'next>( (mask, value): &'next mut Self::Value, id: Index ) -> <Self as LendJoinඞType<'next>>::T

Get a joined component value by a given index.

fn is_unconstrained() -> bool

If this LendJoin typically returns all indices in the mask, then iterating over only it or combined with other joins that are also dangerous will cause the JoinLendIter to go through all indices which is usually not what is wanted and will kill performance.

fn lend_join(self) -> JoinLendIter<Self>where Self: Sized,

Create a joined lending iterator over the contents.

fn maybe(self) -> MaybeJoin<Self>where Self: Sized,

Returns a structure that implements Join/LendJoin/MaybeJoin if the contained T does and that yields all indices, returning None for all missing elements and Some(T) for found elements.

impl<T> ParJoin for MaybeJoin<T>where T: ParJoin,

type Mask = BitSetAll

Type of joined bit mask.

type Type = Option<<T as ParJoin>::Type>

Type of joined components.

type Value = (<T as ParJoin>::Mask, <T as ParJoin>::Value)

Type of joined storages.

unsafe fn open(self) -> (Self::Mask, Self::Value)

Open this join by returning the mask and the storages.

unsafe fn get((mask, value): &Self::Value, id: Index) -> Self::Type

Get a joined component value by a given index.

fn is_unconstrained() -> bool

If this LendJoin typically returns all indices in the mask, then iterating over only it or combined with other joins that are also dangerous will cause the JoinLendIter to go through all indices which is usually not what is wanted and will kill performance.

fn par_join(self) -> JoinParIter<Self>where Self: Sized,

Create a joined parallel iterator over the contents.

impl<T> RepeatableLendGet for MaybeJoin<T>where T: RepeatableLendGet,