Struct sharded_slab::pool::RefMut
source · [−]pub struct RefMut<'a, T, C = DefaultConfig> where
T: Clear + Default,
C: Config, { /* private fields */ }
Expand description
A guard that allows exclusive mutable access to an object in a pool.
While the guard exists, it indicates to the pool that the item the guard references is currently being accessed. If the item is removed from the pool while a guard exists, the removal will be deferred until the guard is dropped. The slot cannot be accessed by other threads while it is accessed mutably.
Implementations
sourceimpl<'a, T, C: Config> RefMut<'a, T, C> where
T: Clear + Default,
C: Config,
impl<'a, T, C: Config> RefMut<'a, T, C> where
T: Clear + Default,
C: Config,
sourcepub fn downgrade(self) -> Ref<'a, T, C>
pub fn downgrade(self) -> Ref<'a, T, C>
Downgrades the mutable guard to an immutable guard, allowing access to the pooled value from other threads.
Examples
let pool = Arc::new(Pool::<String>::new());
let mut guard_mut = pool.clone().create_owned().unwrap();
let key = guard_mut.key();
guard_mut.push_str("Hello");
// The pooled string is currently borrowed mutably, so other threads
// may not access it.
let pool2 = pool.clone();
thread::spawn(move || {
assert!(pool2.get(key).is_none())
}).join().unwrap();
// Downgrade the guard to an immutable reference.
let guard = guard_mut.downgrade();
// Now, other threads may also access the pooled value.
let pool2 = pool.clone();
thread::spawn(move || {
let guard = pool2.get(key)
.expect("the item may now be referenced by other threads");
assert_eq!(guard, String::from("Hello"));
}).join().unwrap();
// We can still access the value immutably through the downgraded guard.
assert_eq!(guard, String::from("Hello"));
Trait Implementations
Auto Trait Implementations
impl<'a, T, C = DefaultConfig> !RefUnwindSafe for RefMut<'a, T, C>
impl<'a, T, C = DefaultConfig> !Send for RefMut<'a, T, C>
impl<'a, T, C = DefaultConfig> !Sync for RefMut<'a, T, C>
impl<'a, T, C> Unpin for RefMut<'a, T, C>
impl<'a, T, C = DefaultConfig> !UnwindSafe for RefMut<'a, T, C>
Blanket Implementations
sourceimpl<T> BorrowMut<T> for T where
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
const: unstable · sourcefn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more