Struct SharedGuard 

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

Resource object that grants shared access to guarded data of type T.

Implementations

impl<'a, T> SharedGuard<'a, T>

where T: ?Sized,

pub fn map<U>(guard: Self, f: impl FnOnce(&T) -> &U) -> SharedGuard<'a, U>

where U: ?Sized,

Converts a SharedGuard<T> into a SharedGuard<U> by applying a projection function to select a sub-component of the guarded data.

The SharedGuard<U> this produces will keep the whole T locked for shared access, but won’t be able to access anything but the chosen sub-component U.

By transforming an existing reader, this leaves the reader count unchanged.

pub fn map_split<U, V>( guard: Self, f: impl FnOnce(&T) -> (&U, &V), ) -> (SharedGuard<'a, U>, SharedGuard<'a, V>)

where U: ?Sized, V: ?Sized,

Converts a SharedGuard<T> into a pair SharedGuard<U> and SharedGuard<V> by applying a projection function to select two sub-components of the guarded data.

Both of the returned guards will keep the whole T locked for shared access, but won’t be able to access access anything but the chosen sub-components U and V (respectively).

This increases the total reader count of the lock by 1.

Panics

There is a maximum number of supported readers on a lock, which is at least usize::MAX/2. This number is very difficult to reach in non-pathological code. However, if you reach it by splitting a reader, this will panic.

Trait Implementations

impl<'a, T: Debug + ?Sized> Debug for SharedGuard<'a, T>

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

Formats the value using the given formatter.

impl<T> Deref for SharedGuard<'_, T>

type Target = T

The resulting type after dereferencing.

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

Dereferences the value.