pub struct ReflectFromReflect { /* private fields */ }
Expand description

Type data that represents the FromReflect trait and allows it to be used dynamically.

FromReflect allows dynamic types (e.g. DynamicStruct, DynamicEnum, etc.) to be converted to their full, concrete types. This is most important when it comes to deserialization where it isn’t guaranteed that every field exists when trying to construct the final output.

However, to do this, you normally need to specify the exact concrete type:

#[derive(Reflect, PartialEq, Eq, Debug)]
struct Foo(#[reflect(default = "default_value")] usize);

fn default_value() -> usize { 123 }

let reflected = DynamicTupleStruct::default();

let concrete: Foo = <Foo as FromReflect>::from_reflect(&reflected).unwrap();

assert_eq!(Foo(123), concrete);

In a dynamic context where the type might not be known at compile-time, this is nearly impossible to do. That is why this type data struct exists— it allows us to construct the full type without knowing what the actual type is.

Example


let mut reflected = DynamicTupleStruct::default();
reflected.set_represented_type(Some(<Foo as Typed>::type_info()));

let registration = registry.get_with_type_path(<Foo as TypePath>::type_path()).unwrap();
let rfr = registration.data::<ReflectFromReflect>().unwrap();

let concrete: Box<dyn Reflect> = rfr.from_reflect(&reflected).unwrap();

assert_eq!(Foo(123), concrete.take::<Foo>().unwrap());

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impl ReflectFromReflect

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pub fn from_reflect( &self, reflect_value: &dyn Reflect ) -> Option<Box<dyn Reflect>>

Perform a FromReflect::from_reflect conversion on the given reflection object.

This will convert the object to a concrete type if it wasn’t already, and return the value as Box<dyn Reflect>.

Trait Implementations§

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impl Clone for ReflectFromReflect

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fn clone(&self) -> ReflectFromReflect

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl<T: FromReflect> FromType<T> for ReflectFromReflect

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fn from_type() -> Self

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

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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

Mutably borrows from an owned value. Read more
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impl<T> Downcast for T
where T: Any,

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

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

Convert Arc<Trait> (where Trait: Downcast) to Arc<Any>. Arc<Any> can then be further downcast into Arc<ConcreteType> where ConcreteType implements Trait.
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T> Instrument for T

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

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
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fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current Span, returning an Instrumented wrapper. Read more
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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

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

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

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<T> TypeData for T
where T: 'static + Send + Sync + Clone,

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impl<T> WithSubscriber for T

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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
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fn with_current_subscriber(self) -> WithDispatch<Self>

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