Struct TxInstants 

pub struct TxInstants { /* private fields */ }

The t ↔ :db/txInstant correspondence for the transactions a value has seen, in both directions.

Both maps are persistent, so carrying them on every database value costs one O(log n) insert per transaction and nothing per clone. They are a property of the recorded transactions rather than of a time view, so a derived view (as-of, since, history) keeps the whole correspondence: naming a view by instant means the same thing whatever view you start from.

:db/txInstant is monotone by construction (the transactor stamps max(now, last + 1)), so ordering by instant and ordering by t agree.

Implementations

impl TxInstants

pub fn instant(&self, t: u64) -> Option<i64>

The commit instant of transaction t.

pub fn t_at(&self, instant: i64) -> u64

The latest t committed at or before instant, or zero when no known transaction is that old (the basis of an empty database).

pub fn len(&self) -> usize

Number of transactions with a known instant.

pub fn is_empty(&self) -> bool

Whether no transaction instant is known.

Trait Implementations

impl Clone for TxInstants

fn clone(&self) -> TxInstants

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for TxInstants

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for TxInstants

fn default() -> TxInstants

Returns the “default value” for a type.