Trait Cursor 

pub trait Cursor: LayoutExt {
    type Storage;

    // Required methods
    fn key_valid(&self, storage: &Self::Storage) -> bool;
    fn val_valid(&self, storage: &Self::Storage) -> bool;
    fn key<'a>(&self, storage: &'a Self::Storage) -> Self::Key<'a>;
    fn val<'a>(&self, storage: &'a Self::Storage) -> Self::Val<'a>;
    fn get_key<'a>(&self, storage: &'a Self::Storage) -> Option<Self::Key<'a>>;
    fn get_val<'a>(&self, storage: &'a Self::Storage) -> Option<Self::Val<'a>>;
    fn map_times<L: FnMut(Self::TimeGat<'_>, Self::DiffGat<'_>)>(
        &mut self,
        storage: &Self::Storage,
        logic: L,
    );
    fn step_key(&mut self, storage: &Self::Storage);
    fn seek_key(&mut self, storage: &Self::Storage, key: Self::Key<'_>);
    fn step_val(&mut self, storage: &Self::Storage);
    fn seek_val(&mut self, storage: &Self::Storage, val: Self::Val<'_>);
    fn rewind_keys(&mut self, storage: &Self::Storage);
    fn rewind_vals(&mut self, storage: &Self::Storage);

    // Provided method
    fn to_vec<K, IK, V, IV>(
        &mut self,
        storage: &Self::Storage,
        into_key: IK,
        into_val: IV,
    ) -> Vec<((K, V), Vec<(Self::Time, Self::Diff)>)>
       where IK: for<'a> Fn(Self::Key<'a>) -> K,
             IV: for<'a> Fn(Self::Val<'a>) -> V { ... }
}

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

Required Associated Types

type Storage

Storage required by the cursor.

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) -> Self::Key<'a>

A reference to the current key. Asserts if invalid.

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

A reference to the current value. Asserts if invalid.

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

Returns a reference to the current key, if valid.

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

Returns a reference to the current value, if valid.

fn map_times<L: FnMut(Self::TimeGat<'_>, Self::DiffGat<'_>)>( &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.

fn seek_key(&mut self, storage: &Self::Storage, key: Self::Key<'_>)

Advances the cursor to the specified key.

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

Advances the cursor to the next value.

fn seek_val(&mut self, storage: &Self::Storage, val: Self::Val<'_>)

Advances the cursor to the specified value.

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 to_vec<K, IK, V, IV>( &mut self, storage: &Self::Storage, into_key: IK, into_val: IV, ) -> Vec<((K, V), Vec<(Self::Time, Self::Diff)>)>

where IK: for<'a> Fn(Self::Key<'a>) -> K, IV: for<'a> Fn(Self::Val<'a>) -> V,

Rewinds the cursor and outputs its contents to a Vec

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl<C, F> Cursor for CursorFilter<C, F>

where C: Cursor, F: FnMut(C::Key<'_>, C::Val<'_>) -> bool + 'static,

type Storage = <C as Cursor>::Storage

impl<C, F> Cursor for CursorFreeze<C, F>

where C: Cursor, F: Fn(C::TimeGat<'_>) -> Option<C::Time>,

type Storage = <C as Cursor>::Storage

impl<C, TInner> Cursor for differential_dataflow::trace::wrappers::enter::CursorEnter<C, TInner>

where C: Cursor, TInner: Refines<C::Time> + Lattice,

type Storage = <C as Cursor>::Storage

impl<C, TInner, F> Cursor for differential_dataflow::trace::wrappers::enter_at::CursorEnter<C, TInner, F>

where C: Cursor, TInner: Refines<C::Time> + Lattice, F: FnMut(C::Key<'_>, C::Val<'_>, C::TimeGat<'_>) -> TInner,

type Storage = <C as Cursor>::Storage

impl<C: Cursor> Cursor for RcBatchCursor<C>

type Storage = Rc<<C as Cursor>::Storage>

impl<C: Cursor> Cursor for CursorFrontier<C, C::Time>

type Storage = <C as Cursor>::Storage

impl<C: Cursor> Cursor for CursorList<C>

type Storage = Vec<<C as Cursor>::Storage>

impl<C: Cursor<Storage: BatchReader>> Cursor for BatchCursorFrontier<C>

type Storage = BatchFrontier<<C as Cursor>::Storage>

impl<C: Cursor, F> Cursor for BatchCursorFilter<C, F>

where F: FnMut(C::Key<'_>, C::Val<'_>) -> bool + 'static,

type Storage = BatchFilter<<C as Cursor>::Storage, F>

impl<C: Cursor, F> Cursor for BatchCursorFreeze<C, F>

where F: Fn(C::TimeGat<'_>) -> Option<C::Time>,

type Storage = BatchFreeze<<C as Cursor>::Storage, F>

impl<L: Layout> Cursor for OrdValCursor<L>

type Storage = OrdValBatch<L>

impl<L: for<'a> Layout<ValContainer: BatchContainer<ReadItem<'a> = &'a ()>>> Cursor for OrdKeyCursor<L>

type Storage = OrdKeyBatch<L>

impl<TInner, C: Cursor> Cursor for differential_dataflow::trace::wrappers::enter::BatchCursorEnter<C, TInner>

where TInner: Refines<C::Time> + Lattice,

type Storage = BatchEnter<<C as Cursor>::Storage, TInner>

impl<TInner, C: Cursor, F> Cursor for differential_dataflow::trace::wrappers::enter_at::BatchCursorEnter<C, TInner, F>

where TInner: Refines<C::Time> + Lattice, F: FnMut(C::Key<'_>, C::Val<'_>, C::TimeGat<'_>) -> TInner,

type Storage = BatchEnter<<C as Cursor>::Storage, TInner, F>