Struct BorrowMut

pub struct BorrowMut<'a, T: ?Sized> { /* private fields */ }

Guard for data exclusively borrowed from a slot in the virtual machine.

These guards are necessary, since we need to guarantee certain forms of access depending on what we do. Releasing the guard releases the access.

Implementations

impl<'a, T: ?Sized> BorrowMut<'a, T>

pub fn map<U: ?Sized>( this: Self, m: impl FnOnce(&mut T) -> &mut U, ) -> BorrowMut<'a, U>

Map the mutable reference.

Examples

use rune::runtime::{BorrowMut, Bytes};
use rune::alloc::try_vec;

let bytes = rune::to_value(Bytes::from_vec(try_vec![1, 2, 3, 4]))?;
let bytes = bytes.borrow_mut::<Bytes>()?;

let mut bytes = BorrowMut::map(bytes, |bytes| &mut bytes[0..2]);

assert_eq!(&mut bytes[..], &mut [1u8, 2u8][..]);

pub fn try_map<U: ?Sized>( this: Self, m: impl FnOnce(&mut T) -> Option<&mut U>, ) -> Result<BorrowMut<'a, U>, Self>

Try to map the mutable reference to a projection.

Examples

use rune::runtime::{BorrowMut, Bytes};
use rune::alloc::try_vec;

let bytes = rune::to_value(Bytes::from_vec(try_vec![1, 2, 3, 4]))?;
let bytes = bytes.borrow_mut::<Bytes>()?;

let Ok(mut bytes) = BorrowMut::try_map(bytes, |bytes| bytes.get_mut(0..2)) else {
    panic!("Conversion failed");
};

assert_eq!(&mut bytes[..], &mut [1u8, 2u8][..]);

Trait Implementations

impl<T> Debug for BorrowMut<'_, T>

where T: Debug + ?Sized,

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

Formats the value using the given formatter.

impl<T: ?Sized> Deref for BorrowMut<'_, T>

type Target = T

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl<T: ?Sized> DerefMut for BorrowMut<'_, T>

fn deref_mut(&mut self) -> &mut Self::Target

Mutably dereferences the value.

impl<F> Future for BorrowMut<'_, F>

where F: Unpin + Future,

type Output = <F as Future>::Output

The type of value produced on completion.

fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output>

Attempts to resolve the future to a final value, registering the current task for wakeup if the value is not yet available.