Struct RefMut

pub struct RefMut<'a, T, C = DefaultConfig>
where
    T: Clear + Default,
    C: Config,
{ /* private fields */ }

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

impl<'a, T, C> RefMut<'a, T, C>

where T: Clear + Default, C: Config,

pub fn key(&self) -> usize

Returns the key used to access the guard.

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

impl<'a, T, C> Debug for RefMut<'a, T, C>

where T: Debug + Clear + Default, C: Config,

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

Formats the value using the given formatter.

impl<'a, T, C> DerefMut for RefMut<'a, T, C>

where T: Clear + Default, C: Config,

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

Mutably dereferences the value.

impl<'a, T, C> Drop for RefMut<'a, T, C>

where T: Clear + Default, C: Config,

fn drop(&mut self)

Executes the destructor for this type.

impl<'a, T, C> PartialEq<T> for RefMut<'a, T, C>

where T: PartialEq<T> + Clear + Default, C: Config,

fn eq(&self, other: &T) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<'a, T, C> Deref for RefMut<'a, T, C>

where T: Clear + Default, C: Config,

type Target = T

The resulting type after dereferencing.

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

Dereferences the value.

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 40 bytes