Struct Context

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pub struct Context<T> { /* private fields */ }

Expand description

Handle to inherited visual defaults created by provide_context.

Accessing a stale handle fails rather than reading a replacement value.

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

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pub fn with<R>(&self, f: impl FnOnce(&T) -> R) -> R

Execute a closure with a shared reference to the context value.

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pub fn with_mut<R>(&self, f: impl FnOnce(&mut T) -> R) -> R

Execute a closure with a mutable reference to the context value.

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pub fn get(&self) -> T
where T: Clone,

Get a cloned value. Requires T: Clone.

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pub fn set(&self, value: T)

Set the context value.

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pub fn replace(&self, value: T) -> T

Replace the context value and return the old value.

Trait Implementations§

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impl<T> Clone for Context<T>

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fn clone(&self) -> Self

Returns a duplicate of the value. Read more

1.0.0 (const: unstable) · Source§

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

Performs copy-assignment from source. Read more

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impl<T> Copy for Context<T>

Auto Trait Implementations§

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impl<T> UnwindSafe for Context<T>
where T: UnwindSafe,

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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<ST, DT> CastableFrom<ST, Initialized, Initialized> for DT
where ST: ?Sized, DT: ?Sized,

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impl<ST, DT> CastableFrom<ST, Uninit, Uninit> for DT
where ST: ?Sized, DT: ?Sized,

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

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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

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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> Downcast for T
where T: Any,

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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.

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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.

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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.

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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.

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impl<T> Downcast<T> for T

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fn downcast(&self) -> &T

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

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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.

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

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

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

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

Converts Arc<Trait> (where Trait: DowncastSync) to Arc<Any>, which can then be downcast into Arc<ConcreteType> where ConcreteType implements Trait.

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