Struct VisitingRef

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

Container that automatically returns ownership of a value to another async context upon exiting scope, allowing immutable access to the value while active.

VisitingRef implements Deref to allow for immutable access to the wrapped value, either explicitly using the unary * operator or implicitly by the compiler under various circumstances. More information can be found in the Deref trait documentation.

For mutable value access, see VisitingMut.

Implementations

impl<T> VisitingRef<T>

pub fn new(value: T) -> (Self, Return<T>)

Creates a new VisitingRef wrapping the given value, along with a future that resolves back the wrapped value once the VisitingRef is dropped.

Examples

use visiting_ref::VisitingRef;

let (item, receiver) = VisitingRef::new(5);
assert_eq!(*item, 5);

drop(item);
let original = receiver.await;
assert_eq!(original, 5);

pub fn run_with<U, R>( value: T, f: impl FnOnce(VisitingRef<T>) -> R, ) -> impl Future<Output = (T, U)>

where R: Future<Output = U>,

Wraps a given T value in a VisitingRef and runs an asynchronous closure with the VisitingRef<T> as its argument.

Examples

use visiting_ref::VisitingRef;

struct Foo {
    value: i32,
}

let foo = Foo { value: 27 };

let (foo, result) = VisitingRef::run_with(foo, |foo| async move { foo.value * 3 }).await;
assert_eq!(result, 81);
assert_eq!(foo.value, 27);

Trait Implementations

impl<T> Binary for VisitingRef<T>

where T: Binary,

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

Formats the value using the given formatter.

impl<T> Debug for VisitingRef<T>

where T: Debug,

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

Formats the value using the given formatter.

impl<T> Deref for VisitingRef<T>

type Target = T

The resulting type after dereferencing.

fn deref(&self) -> &T

Dereferences the value.

impl<T> Display for VisitingRef<T>

where T: Display,

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

Formats the value using the given formatter.

impl<T> From<VisitingMut<T>> for VisitingRef<T>

fn from(value: VisitingMut<T>) -> Self

Converts to this type from the input type.

impl<T> LowerExp for VisitingRef<T>

where T: LowerExp,

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

Formats the value using the given formatter.

impl<T> LowerHex for VisitingRef<T>

where T: LowerHex,

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

Formats the value using the given formatter.

impl<T> Octal for VisitingRef<T>

where T: Octal,

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

Formats the value using the given formatter.

impl<T> Pointer for VisitingRef<T>

where T: Pointer,

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

Formats the value using the given formatter.

impl<T> UpperExp for VisitingRef<T>

where T: UpperExp,

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

Formats the value using the given formatter.

impl<T> UpperHex for VisitingRef<T>

where T: UpperHex,

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

Formats the value using the given formatter.