Trait differential_dataflow::trace::cursor::Cursor

pub trait Cursor<K, V, T, R> {
    type Storage;
    fn key_valid(&self, storage: &Self::Storage) -> bool;
    fn val_valid(&self, storage: &Self::Storage) -> bool;
    fn key<'a>(&self, storage: &'a Self::Storage) -> &'a K;
    fn val<'a>(&self, storage: &'a Self::Storage) -> &'a V;
    fn map_times<L: FnMut(&T, R)>(&mut self, storage: &Self::Storage, logic: L);
    fn step_key(&mut self, storage: &Self::Storage);
    fn seek_key(&mut self, storage: &Self::Storage, key: &K);
    fn step_val(&mut self, storage: &Self::Storage);
    fn seek_val(&mut self, storage: &Self::Storage, val: &V);
    fn rewind_keys(&mut self, storage: &Self::Storage);
    fn rewind_vals(&mut self, storage: &Self::Storage);

    fn get_key<'a>(&self, storage: &'a Self::Storage) -> Option<&'a K> { ... }
    fn get_val<'a>(&self, storage: &'a Self::Storage) -> Option<&'a V> { ... }
}

A cursor for navigating ordered (key, val, time, diff) updates.

Associated Types

type Storage

Type the cursor addresses data in.

Required Methods

fn key_valid(&self, storage: &Self::Storage) -> bool

Indicates if the current key is valid.

A value of false indicates that the cursor has exhausted all keys.

fn val_valid(&self, storage: &Self::Storage) -> bool

Indicates if the current value is valid.

A value of false indicates that the cursor has exhausted all values for this key.

fn key<'a>(&self, storage: &'a Self::Storage) -> &'a K

A reference to the current key. Asserts if invalid.

fn val<'a>(&self, storage: &'a Self::Storage) -> &'a V

A reference to the current value. Asserts if invalid.

fn map_times<L: FnMut(&T, R)>(&mut self, storage: &Self::Storage, logic: L)

Applies logic to each pair of time and difference. Intended for mutation of the closure's scope.

fn step_key(&mut self, storage: &Self::Storage)

Advances the cursor to the next key. Indicates if the key is valid.

fn seek_key(&mut self, storage: &Self::Storage, key: &K)

Advances the cursor to the specified key. Indicates if the key is valid.

fn step_val(&mut self, storage: &Self::Storage)

Advances the cursor to the next value. Indicates if the value is valid.

fn seek_val(&mut self, storage: &Self::Storage, val: &V)

Advances the cursor to the specified value. Indicates if the value is valid.

fn rewind_keys(&mut self, storage: &Self::Storage)

Rewinds the cursor to the first key.

fn rewind_vals(&mut self, storage: &Self::Storage)

Rewinds the cursor to the first value for current key.

Provided Methods

fn get_key<'a>(&self, storage: &'a Self::Storage) -> Option<&'a K>

Returns a reference to the current key, if valid.

fn get_val<'a>(&self, storage: &'a Self::Storage) -> Option<&'a V>

Returns a reference to the current value, if valid.

Implementors

• impl<K, V, T, R, C: Cursor<K, V, T, R>> Cursor<K, V, T, R> for CursorList<K, V, T, R, C> where
    K: Ord,
    V: Ord,  type Storage = Vec<C::Storage>;
• impl<K, V, T, R, C1, C2> Cursor<K, V, T, R> for CursorPair<C1, C2> where
    K: Ord,
    V: Ord,
    C1: Cursor<K, V, T, R>,
    C2: Cursor<K, V, T, R>,  type Storage = (C1::Storage, C2::Storage);
• impl<K, V, T, R> Cursor<K, V, T, R> for OrdValCursor<V, T, R> where
    K: Ord + Clone,
    V: Ord + Clone,
    T: Lattice + Ord + Clone,
    R: Diff,  type Storage = OrdValBatch<K, V, T, R>;
• impl<K: Ord + Clone, T: Lattice + Ord + Clone, R: Diff> Cursor<K, (), T, R> for OrdKeyCursor<T, R> type Storage = OrdKeyBatch<K, T, R>;
• impl<K, V, T, R, C, TInner> Cursor<K, V, Product<T, TInner>, R> for CursorEnter<K, V, T, R, C, TInner> where
    C: Cursor<K, V, T, R>,
    T: Clone,  type Storage = C::Storage;
• impl<K, V, T, R, TInner, B: BatchReader<K, V, T, R>> Cursor<K, V, Product<T, TInner>, R> for BatchCursorEnter<K, V, T, R, B, TInner> where
    T: Clone,  type Storage = BatchEnter<K, V, T, R, B, TInner>;
• impl<K, V, T, R, C, F> Cursor<K, V, T, R> for CursorFreeze<K, V, T, R, C, F> where
    C: Cursor<K, V, T, R>,
    F: Fn(&T) -> Option<T>,  type Storage = C::Storage;
• impl<K, V, T, R, B: BatchReader<K, V, T, R>, F> Cursor<K, V, T, R> for BatchCursorFreeze<K, V, T, R, B, F> where
    F: Fn(&T) -> Option<T>,  type Storage = BatchFreeze<K, V, T, R, B, F>;
• impl<K, V, T, R, B: BatchReader<K, V, T, R>> Cursor<K, V, T, R> for RcBatchCursor<K, V, T, R, B> type Storage = Rc<B>;
• impl<K, V, T, R, B: BatchReader<K, V, T, R> + Abomonation> Cursor<K, V, T, R> for AbomonatedBatchCursor<K, V, T, R, B> type Storage = Abomonated<B, Vec<u8>>;