Trait Cursor

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pub trait Cursor {
    type Storage;
    type Key<'a>: Copy + Ord;
    type ValOwn: Clone + Ord;
    type Val<'a>: Copy + Ord;
    type Time: Lattice + Timestamp;
    type TimeGat<'a>: Copy + Ord;
    type Diff: Semigroup + 'static;
    type DiffGat<'a>: Copy + Ord;
    type KeyContainer: for<'a> BatchContainer<ReadItem<'a> = Self::Key<'a>>;
    type ValContainer: for<'a> BatchContainer<ReadItem<'a> = Self::Val<'a>, Owned = Self::ValOwn>;
    type TimeContainer: for<'a> BatchContainer<ReadItem<'a> = Self::TimeGat<'a>, Owned = Self::Time>;
    type DiffContainer: for<'a> BatchContainer<ReadItem<'a> = Self::DiffGat<'a>, Owned = Self::Diff>;

Show 19 methods    // 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 methods
    fn owned_val(val: Self::Val<'_>) -> Self::ValOwn { ... }
    fn owned_time(time: Self::TimeGat<'_>) -> Self::Time { ... }
    fn owned_diff(diff: Self::DiffGat<'_>) -> Self::Diff { ... }
    fn clone_time_onto(time: Self::TimeGat<'_>, onto: &mut Self::Time) { ... }
    fn populate_key<'a>(
        &mut self,
        storage: &'a Self::Storage,
        key: Self::Key<'a>,
        meet: Option<&Self::Time>,
        target: &mut EditList<Self::Val<'a>, Self::Time, Self::Diff>,
    ) { ... }
    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 { ... }
}

Expand description

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

Required Associated Types§

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type Key<'a>: Copy + Ord

Alias for a borrowed key.

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type Val<'a>: Copy + Ord

Alias for a borrowed val.

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type Time: Lattice + Timestamp

Alias for an owned time.

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type Diff: Semigroup + 'static

Alias for an owned diff.

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type KeyContainer: for<'a> BatchContainer<ReadItem<'a> = Self::Key<'a>>

Container for update keys.

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type ValContainer: for<'a> BatchContainer<ReadItem<'a> = Self::Val<'a>, Owned = Self::ValOwn>

Container for update vals.

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type TimeContainer: for<'a> BatchContainer<ReadItem<'a> = Self::TimeGat<'a>, Owned = Self::Time>

Container for times.

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type DiffContainer: for<'a> BatchContainer<ReadItem<'a> = Self::DiffGat<'a>, Owned = Self::Diff>

Container for diffs.

Required Methods§

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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.

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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.

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

A reference to the current key. Asserts if invalid.

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

A reference to the current value. Asserts if invalid.

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

Returns a reference to the current key, if valid.

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

Returns a reference to the current value, if valid.

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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.

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

Advances the cursor to the next key.

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

Advances the cursor to the specified key.

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

Advances the cursor to the next value.

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

Advances the cursor to the specified value.

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

Rewinds the cursor to the first key.

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

Rewinds the cursor to the first value for current key.

Provided Methods§

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fn owned_val(val: Self::Val<'_>) -> Self::ValOwn

Construct an owned val from a reference.

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fn owned_time(time: Self::TimeGat<'_>) -> Self::Time

Construct an owned time from a reference.

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fn owned_diff(diff: Self::DiffGat<'_>) -> Self::Diff

Construct an owned diff from a reference.

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fn clone_time_onto(time: Self::TimeGat<'_>, onto: &mut Self::Time)

Clones a reference time onto an owned time.

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fn populate_key<'a>( &mut self, storage: &'a Self::Storage, key: Self::Key<'a>, meet: Option<&Self::Time>, target: &mut EditList<Self::Val<'a>, Self::Time, Self::Diff>, )

Loads target with all updates associated with the supplied key.

First target is cleared, and then if we find key we populated it with each of its (val, time, diff) updates. If meet is supplied, the time is joined with each time in the updates, to advance the times before consolidation.

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