Struct valence::ecs::query::FilteredAccess

pub struct FilteredAccess<T>
where
    T: SparseSetIndex,
{ /* private fields */ }

An Access that has been filtered to include and exclude certain combinations of elements.

Used internally to statically check if queries are disjoint.

Subtle: a read or write in access should not be considered to imply a with access.

For example consider Query<Option<&T>> this only has a read of T as doing otherwise would allow for queries to be considered disjoint when they shouldn’t:

• Query<(&mut T, Option<&U>)> read/write T, read U, with U
• Query<&mut T, Without<U>> read/write T, without U from this we could reasonably conclude that the queries are disjoint but they aren’t.

In order to solve this the actual access that Query<(&mut T, Option<&U>)> has is read/write T, read U. It must still have a read U access otherwise the following queries would be incorrectly considered disjoint:

• Query<&mut T> read/write T
• Query<Option<&T>> accesses nothing

See comments the WorldQuery impls of AnyOf/Option/Or for more information.

Implementations

impl<T> FilteredAccess<T>

where T: SparseSetIndex,

pub fn access(&self) -> &Access<T>

Returns a reference to the underlying unfiltered access.

pub fn access_mut(&mut self) -> &mut Access<T>

Returns a mutable reference to the underlying unfiltered access.

pub fn add_read(&mut self, index: T)

Adds access to the element given by index.

pub fn add_write(&mut self, index: T)

Adds exclusive access to the element given by index.

pub fn and_with(&mut self, index: T)

Adds a With filter: corresponds to a conjunction (AND) operation.

Suppose we begin with Or<(With<A>, With<B>)>, which is represented by an array of two AccessFilter instances. Adding AND With<C> via this method transforms it into the equivalent of Or<((With<A>, With<C>), (With<B>, With<C>))>.

pub fn and_without(&mut self, index: T)

Adds a Without filter: corresponds to a conjunction (AND) operation.

Suppose we begin with Or<(With<A>, With<B>)>, which is represented by an array of two AccessFilter instances. Adding AND Without<C> via this method transforms it into the equivalent of Or<((With<A>, Without<C>), (With<B>, Without<C>))>.

pub fn append_or(&mut self, other: &FilteredAccess<T>)

Appends an array of filters: corresponds to a disjunction (OR) operation.

As the underlying array of filters represents a disjunction, where each element (AccessFilters) represents a conjunction, we can simply append to the array.

pub fn extend_access(&mut self, other: &FilteredAccess<T>)

Adds all of the accesses from other to self.

pub fn is_compatible(&self, other: &FilteredAccess<T>) -> bool

Returns true if this and other can be active at the same time.

pub fn get_conflicts(&self, other: &FilteredAccess<T>) -> Vec<T>

Returns a vector of elements that this and other cannot access at the same time.

pub fn extend(&mut self, other: &FilteredAccess<T>)

Adds all access and filters from other.

Corresponds to a conjunction operation (AND) for filters.

Extending Or<(With<A>, Without<B>)> with Or<(With<C>, Without<D>)> will result in Or<((With<A>, With<C>), (With<A>, Without<D>), (Without<B>, With<C>), (Without<B>, Without<D>))>.

pub fn read_all(&mut self)

Sets the underlying unfiltered access as having access to all indexed elements.

pub fn write_all(&mut self)

Sets the underlying unfiltered access as having mutable access to all indexed elements.

pub fn is_subset(&self, other: &FilteredAccess<T>) -> bool

Returns true if the set is a subset of another, i.e. other contains at least all the values in self.

pub fn with_filters(&self) -> impl Iterator<Item = T>

Returns the indices of the elements that this access filters for.

pub fn without_filters(&self) -> impl Iterator<Item = T>

Returns the indices of the elements that this access filters out.

Trait Implementations

impl<T> Clone for FilteredAccess<T>

where T: Clone + SparseSetIndex,

fn clone(&self) -> FilteredAccess<T>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T> Debug for FilteredAccess<T>

where T: Debug + SparseSetIndex,

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl<T> Default for FilteredAccess<T>

where T: SparseSetIndex,

fn default() -> FilteredAccess<T>

Returns the “default value” for a type.

impl<T> From<FilteredAccess<T>> for FilteredAccessSet<T>

where T: SparseSetIndex,

fn from(filtered_access: FilteredAccess<T>) -> FilteredAccessSet<T>

Converts to this type from the input type.

impl<T> PartialEq for FilteredAccess<T>

where T: PartialEq + SparseSetIndex,

fn eq(&self, other: &FilteredAccess<T>) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<T> Eq for FilteredAccess<T>

where T: Eq + SparseSetIndex,

impl<T> StructuralPartialEq for FilteredAccess<T>

where T: SparseSetIndex,