EntityGeneration

Struct EntityGeneration 

Source
pub struct EntityGeneration(/* private fields */);
Expand description

This tracks different versions or generations of an EntityRow. Importantly, this can wrap, meaning each generation is not necessarily unique per EntityRow.

This should be treated as a opaque identifier, and its internal representation may be subject to change.

§Aliasing

Internally EntityGeneration wraps a u32, so it can’t represent every possible generation. Eventually, generations can (and do) wrap or alias. This can cause Entity and EntityGeneration values to be equal while still referring to different conceptual entities. This can cause some surprising behavior:

let (aliased, did_alias) = EntityGeneration::FIRST.after_versions(1u32 << 31).after_versions_and_could_alias(1u32 << 31);
assert!(did_alias);
assert!(EntityGeneration::FIRST == aliased);

This can cause some unintended side effects. See Entity docs for practical concerns and how to minimize any risks.

Implementations§

Source§

impl EntityGeneration

Source

pub const FIRST: EntityGeneration

Represents the first generation of an EntityRow.

Source

pub const fn to_bits(self) -> u32

Gets some bits that represent this value. The bits are opaque and should not be regarded as meaningful.

Source

pub const fn from_bits(bits: u32) -> EntityGeneration

Reconstruct an EntityGeneration previously destructured with EntityGeneration::to_bits.

Only useful when applied to results from to_bits in the same instance of an application.

Source

pub const fn after_versions(self, versions: u32) -> EntityGeneration

Returns the EntityGeneration that would result from this many more versions of the corresponding EntityRow from passing.

Source

pub const fn after_versions_and_could_alias( self, versions: u32, ) -> (EntityGeneration, bool)

Identical to after_versions but also returns a bool indicating if, after these versions, one such version could conflict with a previous one.

If this happens, this will no longer uniquely identify a version of an EntityRow. This is called entity aliasing.

Source

pub const fn cmp_approx(&self, other: &EntityGeneration) -> Ordering

Compares two generations.

Generations that are later will be Greater than earlier ones.

let later_generation = EntityGeneration::FIRST.after_versions(400);
assert_eq!(EntityGeneration::FIRST.cmp_approx(&later_generation), Ordering::Less);

let (aliased, did_alias) = EntityGeneration::FIRST.after_versions(400).after_versions_and_could_alias(u32::MAX);
assert!(did_alias);
assert_eq!(EntityGeneration::FIRST.cmp_approx(&aliased), Ordering::Less);

Ordering will be incorrect and non-transitive for distant generations:

let later_generation = EntityGeneration::FIRST.after_versions(3u32 << 31);
let much_later_generation = later_generation.after_versions(3u32 << 31);

// while these orderings are correct and pass assertions...
assert_eq!(EntityGeneration::FIRST.cmp_approx(&later_generation), Ordering::Less);
assert_eq!(later_generation.cmp_approx(&much_later_generation), Ordering::Less);

// ... this ordering is not and the assertion fails!
assert_eq!(EntityGeneration::FIRST.cmp_approx(&much_later_generation), Ordering::Less);

Because of this, EntityGeneration does not implement Ord/PartialOrd.

Trait Implementations§

Source§

impl Clone for EntityGeneration

Source§

fn clone(&self) -> EntityGeneration

Returns a duplicate of the value. Read more
1.0.0 · Source§

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

Performs copy-assignment from source. Read more
Source§

impl Debug for EntityGeneration

Source§

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

Formats the value using the given formatter. Read more
Source§

impl Display for EntityGeneration

Source§

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

Formats the value using the given formatter. Read more
Source§

impl FromReflect for EntityGeneration

Source§

fn from_reflect( reflect: &(dyn PartialReflect + 'static), ) -> Option<EntityGeneration>

Constructs a concrete instance of Self from a reflected value.
Source§

fn take_from_reflect( reflect: Box<dyn PartialReflect>, ) -> Result<Self, Box<dyn PartialReflect>>

Attempts to downcast the given value to Self using, constructing the value using from_reflect if that fails. Read more
Source§

impl GetTypeRegistration for EntityGeneration

Source§

fn get_type_registration() -> TypeRegistration

Returns the default TypeRegistration for this type.
Source§

fn register_type_dependencies(_registry: &mut TypeRegistry)

Registers other types needed by this type. Read more
Source§

impl Hash for EntityGeneration

Source§

fn hash<__H>(&self, state: &mut __H)
where __H: Hasher,

Feeds this value into the given Hasher. Read more
1.3.0 · Source§

fn hash_slice<H>(data: &[Self], state: &mut H)
where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher. Read more
Source§

impl PartialEq for EntityGeneration

Source§

fn eq(&self, other: &EntityGeneration) -> bool

Tests for self and other values to be equal, and is used by ==.
1.0.0 · Source§

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

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

impl PartialReflect for EntityGeneration

Source§

fn get_represented_type_info(&self) -> Option<&'static TypeInfo>

Returns the TypeInfo of the type represented by this value. Read more
Source§

fn to_dynamic(&self) -> Box<dyn PartialReflect>

Converts this reflected value into its dynamic representation based on its kind. Read more
Source§

fn try_apply( &mut self, value: &(dyn PartialReflect + 'static), ) -> Result<(), ApplyError>

Tries to apply a reflected value to this value. Read more
Source§

fn reflect_kind(&self) -> ReflectKind

Returns a zero-sized enumeration of “kinds” of type. Read more
Source§

fn reflect_ref(&self) -> ReflectRef<'_>

Returns an immutable enumeration of “kinds” of type. Read more
Source§

fn reflect_mut(&mut self) -> ReflectMut<'_>

Returns a mutable enumeration of “kinds” of type. Read more
Source§

fn reflect_owned(self: Box<EntityGeneration>) -> ReflectOwned

Returns an owned enumeration of “kinds” of type. Read more
Source§

fn try_into_reflect( self: Box<EntityGeneration>, ) -> Result<Box<dyn Reflect>, Box<dyn PartialReflect>>

Attempts to cast this type to a boxed, fully-reflected value.
Source§

fn try_as_reflect(&self) -> Option<&(dyn Reflect + 'static)>

Attempts to cast this type to a fully-reflected value.
Source§

fn try_as_reflect_mut(&mut self) -> Option<&mut (dyn Reflect + 'static)>

Attempts to cast this type to a mutable, fully-reflected value.
Source§

fn into_partial_reflect(self: Box<EntityGeneration>) -> Box<dyn PartialReflect>

Casts this type to a boxed, reflected value. Read more
Source§

fn as_partial_reflect(&self) -> &(dyn PartialReflect + 'static)

Casts this type to a reflected value. Read more
Source§

fn as_partial_reflect_mut(&mut self) -> &mut (dyn PartialReflect + 'static)

Casts this type to a mutable, reflected value. Read more
Source§

fn reflect_hash(&self) -> Option<u64>

Returns a hash of the value (which includes the type). Read more
Source§

fn reflect_partial_eq( &self, value: &(dyn PartialReflect + 'static), ) -> Option<bool>

Returns a “partial equality” comparison result. Read more
Source§

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

Debug formatter for the value. Read more
Source§

fn reflect_clone(&self) -> Result<Box<dyn Reflect>, ReflectCloneError>

Attempts to clone Self using reflection. Read more
Source§

fn apply(&mut self, value: &(dyn PartialReflect + 'static))

Applies a reflected value to this value. Read more
Source§

fn reflect_clone_and_take<T>(&self) -> Result<T, ReflectCloneError>
where T: 'static, Self: Sized + TypePath,

For a type implementing PartialReflect, combines reflect_clone and take in a useful fashion, automatically constructing an appropriate ReflectCloneError if the downcast fails. Read more
Source§

fn is_dynamic(&self) -> bool

Indicates whether or not this type is a dynamic type. Read more
Source§

impl Reflect for EntityGeneration

Source§

fn into_any(self: Box<EntityGeneration>) -> Box<dyn Any>

Returns the value as a Box<dyn Any>. Read more
Source§

fn as_any(&self) -> &(dyn Any + 'static)

Returns the value as a &dyn Any. Read more
Source§

fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)

Returns the value as a &mut dyn Any. Read more
Source§

fn into_reflect(self: Box<EntityGeneration>) -> Box<dyn Reflect>

Casts this type to a boxed, fully-reflected value.
Source§

fn as_reflect(&self) -> &(dyn Reflect + 'static)

Casts this type to a fully-reflected value.
Source§

fn as_reflect_mut(&mut self) -> &mut (dyn Reflect + 'static)

Casts this type to a mutable, fully-reflected value.
Source§

fn set(&mut self, value: Box<dyn Reflect>) -> Result<(), Box<dyn Reflect>>

Performs a type-checked assignment of a reflected value to this value. Read more
Source§

impl TypePath for EntityGeneration

Source§

fn type_path() -> &'static str

Returns the fully qualified path of the underlying type. Read more
Source§

fn short_type_path() -> &'static str

Returns a short, pretty-print enabled path to the type. Read more
Source§

fn type_ident() -> Option<&'static str>

Returns the name of the type, or None if it is anonymous. Read more
Source§

fn crate_name() -> Option<&'static str>

Returns the name of the crate the type is in, or None if it is anonymous. Read more
Source§

fn module_path() -> Option<&'static str>

Returns the path to the module the type is in, or None if it is anonymous. Read more
Source§

impl Typed for EntityGeneration

Source§

fn type_info() -> &'static TypeInfo

Returns the compile-time info for the underlying type.
Source§

impl Copy for EntityGeneration

Source§

impl Eq for EntityGeneration

Source§

impl StructuralPartialEq for EntityGeneration

Auto Trait Implementations§

Blanket Implementations§

Source§

impl<T> Any for T
where T: 'static + ?Sized,

Source§

fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
Source§

impl<T, U> AsBindGroupShaderType<U> for T
where U: ShaderType, &'a T: for<'a> Into<U>,

Source§

fn as_bind_group_shader_type(&self, _images: &RenderAssets<GpuImage>) -> U

Return the T ShaderType for self. When used in AsBindGroup derives, it is safe to assume that all images in self exist.
Source§

impl<T> Borrow<T> for T
where T: ?Sized,

Source§

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
Source§

impl<T> BorrowMut<T> for T
where T: ?Sized,

Source§

fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
Source§

impl<T> CloneToUninit for T
where T: Clone,

Source§

unsafe fn clone_to_uninit(&self, dest: *mut u8)

🔬This is a nightly-only experimental API. (clone_to_uninit)
Performs copy-assignment from self to dest. Read more
Source§

impl<T> Downcast for T
where T: Any,

Source§

fn into_any(self: Box<T>) -> Box<dyn Any>

Converts Box<dyn Trait> (where Trait: Downcast) to Box<dyn Any>, which can then be downcast into Box<dyn ConcreteType> where ConcreteType implements Trait.
Source§

fn into_any_rc(self: Rc<T>) -> Rc<dyn Any>

Converts Rc<Trait> (where Trait: Downcast) to Rc<Any>, which can then be further downcast into Rc<ConcreteType> where ConcreteType implements Trait.
Source§

fn as_any(&self) -> &(dyn Any + 'static)

Converts &Trait (where Trait: Downcast) to &Any. This is needed since Rust cannot generate &Any’s vtable from &Trait’s.
Source§

fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)

Converts &mut Trait (where Trait: Downcast) to &Any. This is needed since Rust cannot generate &mut Any’s vtable from &mut Trait’s.
Source§

impl<T> Downcast for T
where T: Any,

Source§

fn into_any(self: Box<T>) -> Box<dyn Any>

Convert Box<dyn Trait> (where Trait: Downcast) to Box<dyn Any>. Box<dyn Any> can then be further downcast into Box<ConcreteType> where ConcreteType implements Trait.
Source§

fn into_any_rc(self: Rc<T>) -> Rc<dyn Any>

Convert Rc<Trait> (where Trait: Downcast) to Rc<Any>. Rc<Any> can then be further downcast into Rc<ConcreteType> where ConcreteType implements Trait.
Source§

fn as_any(&self) -> &(dyn Any + 'static)

Convert &Trait (where Trait: Downcast) to &Any. This is needed since Rust cannot generate &Any’s vtable from &Trait’s.
Source§

fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)

Convert &mut Trait (where Trait: Downcast) to &Any. This is needed since Rust cannot generate &mut Any’s vtable from &mut Trait’s.
Source§

impl<T> DowncastSend for T
where T: Any + Send,

Source§

fn into_any_send(self: Box<T>) -> Box<dyn Any + Send>

Converts Box<Trait> (where Trait: DowncastSend) to Box<dyn Any + Send>, which can then be downcast into Box<ConcreteType> where ConcreteType implements Trait.
Source§

impl<T> DowncastSync for T
where T: Any + Send + Sync,

Source§

fn into_any_arc(self: Arc<T>) -> Arc<dyn Any + Sync + Send>

Convert Arc<Trait> (where Trait: Downcast) to Arc<Any>. Arc<Any> can then be further downcast into Arc<ConcreteType> where ConcreteType implements Trait.
Source§

impl<T> DynEq for T
where T: Any + Eq,

Source§

fn dyn_eq(&self, other: &(dyn DynEq + 'static)) -> bool

This method tests for self and other values to be equal. Read more
Source§

impl<T> DynHash for T
where T: DynEq + Hash,

Source§

fn dyn_hash(&self, state: &mut dyn Hasher)

Feeds this value into the given Hasher.
Source§

impl<T> DynamicTypePath for T
where T: TypePath,

Source§

impl<T> DynamicTyped for T
where T: Typed,

Source§

impl<Q, K> Equivalent<K> for Q
where Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,

Source§

fn equivalent(&self, key: &K) -> bool

Compare self to key and return true if they are equal.
Source§

impl<Q, K> Equivalent<K> for Q
where Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,

Source§

fn equivalent(&self, key: &K) -> bool

Checks if this value is equivalent to the given key. Read more
Source§

impl<T> From<T> for T

Source§

fn from(t: T) -> T

Returns the argument unchanged.

Source§

impl<T> GetPath for T
where T: Reflect + ?Sized,

Source§

fn reflect_path<'p>( &self, path: impl ReflectPath<'p>, ) -> Result<&(dyn PartialReflect + 'static), ReflectPathError<'p>>

Returns a reference to the value specified by path. Read more
Source§

fn reflect_path_mut<'p>( &mut self, path: impl ReflectPath<'p>, ) -> Result<&mut (dyn PartialReflect + 'static), ReflectPathError<'p>>

Returns a mutable reference to the value specified by path. Read more
Source§

fn path<'p, T>( &self, path: impl ReflectPath<'p>, ) -> Result<&T, ReflectPathError<'p>>
where T: Reflect,

Returns a statically typed reference to the value specified by path. Read more
Source§

fn path_mut<'p, T>( &mut self, path: impl ReflectPath<'p>, ) -> Result<&mut T, ReflectPathError<'p>>
where T: Reflect,

Returns a statically typed mutable reference to the value specified by path. Read more
Source§

impl<T, W> HasTypeWitness<W> for T
where W: MakeTypeWitness<Arg = T>, T: ?Sized,

Source§

const WITNESS: W = W::MAKE

A constant of the type witness
Source§

impl<T> Identity for T
where T: ?Sized,

Source§

const TYPE_EQ: TypeEq<T, <T as Identity>::Type> = TypeEq::NEW

Proof that Self is the same type as Self::Type, provides methods for casting between Self and Self::Type.
Source§

type Type = T

The same type as Self, used to emulate type equality bounds (T == U) with associated type equality constraints (T: Identity<Type = U>).
Source§

impl<T> Instrument for T

Source§

fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
Source§

fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current Span, returning an Instrumented wrapper. Read more
Source§

impl<T, U> Into<U> for T
where U: From<T>,

Source§

fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

Source§

impl<T> IntoEither for T

Source§

fn into_either(self, into_left: bool) -> Either<Self, Self>

Converts self into a Left variant of Either<Self, Self> if into_left is true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
Source§

fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
where F: FnOnce(&Self) -> bool,

Converts self into a Left variant of Either<Self, Self> if into_left(&self) returns true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
Source§

impl<T> IntoResult<T> for T

Source§

fn into_result(self) -> Result<T, RunSystemError>

Converts this type into the system output type.
Source§

impl<A> Is for A
where A: Any,

Source§

fn is<T>() -> bool
where T: Any,

Checks if the current type “is” another type, using a TypeId equality comparison. This is most useful in the context of generic logic. Read more
Source§

impl<T> ToOwned for T
where T: Clone,

Source§

type Owned = T

The resulting type after obtaining ownership.
Source§

fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
Source§

fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
Source§

impl<T> ToSmolStr for T
where T: Display + ?Sized,

Source§

impl<T> ToString for T
where T: Display + ?Sized,

Source§

fn to_string(&self) -> String

Converts the given value to a String. Read more
Source§

impl<T, U> TryFrom<U> for T
where U: Into<T>,

Source§

type Error = Infallible

The type returned in the event of a conversion error.
Source§

fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
Source§

impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

Source§

type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
Source§

fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
Source§

impl<T> TypeData for T
where T: 'static + Send + Sync + Clone,

Source§

fn clone_type_data(&self) -> Box<dyn TypeData>

Creates a type-erased clone of this value.
Source§

impl<T> WithSubscriber for T

Source§

fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
where S: Into<Dispatch>,

Attaches the provided Subscriber to this type, returning a WithDispatch wrapper. Read more
Source§

fn with_current_subscriber(self) -> WithDispatch<Self>

Attaches the current default Subscriber to this type, returning a WithDispatch wrapper. Read more
Source§

impl<T> ConditionalSend for T
where T: Send,

Source§

impl<T> Reflectable for T

Source§

impl<T> Settings for T
where T: 'static + Send + Sync,

Source§

impl<T> WasmNotSend for T
where T: Send,

Source§

impl<T> WasmNotSendSync for T

Source§

impl<T> WasmNotSync for T
where T: Sync,