Struct Segment

pub struct Segment<'a, T>
where
    T: Clone + PartialEq,
{ /* private fields */ }

A segment is a part of an event log.

It’s a list of events followed by a projection, called a “snapshot”. Creating a new segment will make the former segments snapshot immutable, and a new (mutable) segment is created.

Snapshots allow for faster history traversal, as not the entire event log needs to be replayed in order to project an earlier state, unlike a single-segment event log.

Implementations

impl<'a, T> Segment<'a, T>

where T: Clone + PartialEq,

pub fn new() -> Segment<'a, T>

Creates a new segment

The new segment will have a timestamp of the current time, and won’t have any prior history associated with it.

pub fn from_projection( projection: Vec<Cow<'a, T>>, events: Vec<Event<'a, T>>, ) -> Segment<'a, T>

Creates a new segment from a given projection and event log at the current time

pub fn get_time(&self) -> &Timestamp

Returns a shared reference to the timestamp of this segment

pub fn get_projection(&self) -> &Vec<Cow<'a, T>>

Returns the current projection

pub fn project_at_onto( &self, timestamp: &Timestamp, snapshot: Vec<Cow<'a, T>>, ) -> Option<Vec<Cow<'a, T>>>

Projects the segments events predating a specified timestamp onto a given snapshot

pub fn push(&mut self, event: Event<'a, T>) -> Result<()>

Applies and appends an event to the segments snapshot and log, respectively (checked)

pub fn prepend(&mut self, other: Self) -> Result<()>

Merges two consecutive segments by prepending the other before this one (checked)

pub fn prepend_unchecked(&mut self, other: Self)

Merges two consecutive segments by prepending the other before this one (unchecked)

Trait Implementations

impl<'a, T> Clone for Segment<'a, T>

where T: Clone + PartialEq + Clone,

fn clone(&self) -> Segment<'a, T>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<'a, T> Debug for Segment<'a, T>

where T: Clone + PartialEq + Debug,

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

Formats the value using the given formatter.

impl<'de, 'a, T> Deserialize<'de> for Segment<'a, T>

where T: Clone + PartialEq + Deserialize<'de>,

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<'a, T> Serialize for Segment<'a, T>

where T: Clone + PartialEq + Serialize,

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.