Struct alloc::collections::btree::borrow::DormantMutRef

pub struct DormantMutRef<'a, T> {
    ptr: NonNull<T>,
    _marker: PhantomData<&'a mut T>,
}

Models a reborrow of some unique reference, when you know that the reborrow and all its descendants (i.e., all pointers and references derived from it) will not be used any more at some point, after which you want to use the original unique reference again.

The borrow checker usually handles this stacking of borrows for you, but some control flows that accomplish this stacking are too complicated for the compiler to follow. A DormantMutRef allows you to check borrowing yourself, while still expressing its stacked nature, and encapsulating the raw pointer code needed to do this without undefined behavior.

Fields

ptr: NonNull<T>

_marker: PhantomData<&'a mut T>

Implementations

impl<'a, T> DormantMutRef<'a, T>

pub fn new(t: &'a mut T) -> (&'a mut T, Self)

Capture a unique borrow, and immediately reborrow it. For the compiler, the lifetime of the new reference is the same as the lifetime of the original reference, but you promise to use it for a shorter period.

pub unsafe fn awaken(self) -> &'a mut T

Revert to the unique borrow initially captured.

Safety

The reborrow must have ended, i.e., the reference returned by new and all pointers and references derived from it, must not be used anymore.

pub unsafe fn reborrow(&mut self) -> &'a mut T

Borrows a new mutable reference from the unique borrow initially captured.

Safety

The reborrow must have ended, i.e., the reference returned by new and all pointers and references derived from it, must not be used anymore.

pub unsafe fn reborrow_shared(&self) -> &'a T

Borrows a new shared reference from the unique borrow initially captured.

Safety

The reborrow must have ended, i.e., the reference returned by new and all pointers and references derived from it, must not be used anymore.

Trait Implementations

impl<'a, T> Send for DormantMutRef<'a, T>where &'a mut T: Send,

impl<'a, T> Sync for DormantMutRef<'a, T>where &'a mut T: Sync,