Trait LayerIterator

pub trait LayerIterator<K, V>: Send + Sync {
    // Required methods
    fn advance<'life0, 'async_trait>(
        &'life0 mut self,
    ) -> Pin<Box<dyn Future<Output = Result<(), Error>> + Send + 'async_trait>>
       where Self: 'async_trait,
             'life0: 'async_trait;
    fn get(&self) -> Option<ItemRef<'_, K, V>>;

    // Provided method
    fn filter<'async_trait, P>(
        self,
        predicate: P,
    ) -> Pin<Box<dyn Future<Output = Result<FilterLayerIterator<Self, P, K, V>, Error>> + Send + 'async_trait>>
       where P: for<'b> Fn(ItemRef<'b, K, V>) -> bool + Send + Sync + 'async_trait,
             Self: Sized + 'async_trait,
             K: Send + Sync,
             V: Send + Sync { ... }
}

Something that implements LayerIterator is returned by the seek function.

Required Methods

fn advance<'life0, 'async_trait>( &'life0 mut self, ) -> Pin<Box<dyn Future<Output = Result<(), Error>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait,

Advances the iterator.

fn get(&self) -> Option<ItemRef<'_, K, V>>

Returns the current item. This will be None if called when the iterator is first crated i.e. before either seek or advance has been called, and None if the iterator has reached the end of the layer.

Provided Methods

fn filter<'async_trait, P>( self, predicate: P, ) -> Pin<Box<dyn Future<Output = Result<FilterLayerIterator<Self, P, K, V>, Error>> + Send + 'async_trait>>

where P: for<'b> Fn(ItemRef<'b, K, V>) -> bool + Send + Sync + 'async_trait, Self: Sized + 'async_trait, K: Send + Sync, V: Send + Sync,

Creates an iterator that only yields items from the underlying iterator for which predicate returns true.

Implementors

impl<'a, K: Key + LayerKey + OrdLowerBound, V: Value> LayerIterator<K, V> for MergerIterator<'a, '_, K, V>

impl<'iter, K, V> LayerIterator<K, V> for BoxedLayerIterator<'iter, K, V>

impl<I, P, K, V> LayerIterator<K, V> for FilterLayerIterator<I, P, K, V>

where I: LayerIterator<K, V>, P: for<'b> Fn(ItemRef<'b, K, V>) -> bool + Send + Sync, K: Send + Sync, V: Send + Sync,

impl<I: LayerIterator<AllocatorKey, AllocatorValue>> LayerIterator<AllocatorKeyV32, AllocatorValueV32> for CoalescingIterator<I>