Struct QueryBorrow

pub struct QueryBorrow<'w, Q, F = All>
where
    Q: Fetch<'w>,
    F: Fetch<'w>,
{ /* private fields */ }

A lazily prepared query which borrows and hands out chunk iterators for each archetype matched.

The borrowing is lazy, as such, calling QueryBorrow::get will only borrow the one required archetype. QueryBorrow::iter will borrow the components from all archetypes and release them once the prepared query drops. Subsequent calls to iter will use the same borrow.

Implementations

impl<'w, Q, F> QueryBorrow<'w, Q, F>

where Q: Fetch<'w>, F: Fetch<'w>,

pub fn iter<'q>(&'q mut self) -> QueryIter<'w, 'q, Q, F>

where 'w: 'q,

Iterate all items matched by query and filter.

pub fn first(&mut self) -> Option<<Q as FetchItem<'_>>::Item>

Returns the first item

pub fn iter_batched<'q>(&'q mut self) -> BatchedIter<'w, 'q, Q, F>

where 'w: 'q,

Iterate all items matched by query and filter.

pub fn for_each( &mut self, func: impl FnMut(<Q as FetchItem<'_>>::Item) + Send + Sync, )

Execute a closure for each item in the iterator.

This is more efficient than .iter().for_each(|v| {}) as the archetypes can be temporarily borrowed.

pub fn par_for_each( &mut self, func: impl Fn(<Q as FetchItem<'_>>::Item) + Send + Sync, )

where Q: Sync, Q::Prepared: Send, for<'x> <Q::Prepared as PreparedFetch<'x>>::Chunk: Send, F: Sync, F::Prepared: Send,

Available on crate feature rayon only.

Shorthand for:

self.iter_batched()
    .par_bridge()
    .for_each(|v| v.for_each(&func))

pub fn clear_borrows(&mut self)

Release all borrowed archetypes

pub fn count<'q>(&'q mut self) -> usize

where 'w: 'q,

Consumes the iterator and returns the number of entities visited. Faster than self.iter().count()

pub fn get( &mut self, id: Entity, ) -> Result<<Q::Prepared as PreparedFetch<'_>>::Item>

Get the fetch items for an entity.

Trait Implementations

impl<'w, 'q, Q, F> IntoIterator for &'q mut QueryBorrow<'w, Q, F>

where Q: Fetch<'w>, F: Fetch<'w>, 'w: 'q,

type Item = <<Q as Fetch<'w>>::Prepared as PreparedFetch<'q>>::Item

The type of the elements being iterated over.

type IntoIter = QueryIter<'w, 'q, Q, F>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.