Struct Group 

pub struct Group<K, V> { /* private fields */ }

A Group represents a namespace in which work can be deduplicated by key.

Only one caller per key executes the function; concurrent callers for the same key receive the same result once it is ready.

Panics

The function passed to call_async must not panic. If it panics, all waiting callers will hang forever because the value will never be stored and they will never be notified.

Implementations

impl<K, V> Group<K, V>

pub fn new() -> Self

Creates a new empty Group.

impl<K, V> Group<K, V>

where K: Eq + Hash,

pub fn forget(&self, key: &K)

Tells the Group to forget about a key. Future calls to [call_async] for this key will execute the function rather than waiting for an earlier call to complete.

If no call is in-flight for the given key, this is a no-op.

impl<K, V> Group<K, V>

where K: Eq + Hash + Clone + Send + Sync, V: Clone + Send,

pub async fn call_async<F, Fut>(&self, key: K, f: F) -> Call<V>

where F: FnOnce() -> Fut + Send, Fut: Future<Output = V> + Send,

Executes f for the given key, coalescing duplicate callers.

If no other call is in-flight for key, this call executes f and returns its result with shared = false.

If another call for the same key is already in-flight, this call awaits that call’s completion and returns the same result with shared = true.

Panics

f must not panic. See the type-level docs.

Trait Implementations

impl<K, V> Clone for Group<K, V>

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<K, V> Default for Group<K, V>

fn default() -> Self

Returns the “default value” for a type.