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

Returns the key used to access the guard.

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

Formats the value using the given formatter. Read more

The resulting type after dereferencing.

Dereferences the value.

Mutably dereferences the value.

Executes the destructor for this type. Read more

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.