Struct RunFeedHeads 

pub struct RunFeedHeads {
    pub epoch: Option<LineageId>,
    pub lifecycle_head: u64,
    pub activity_head: u64,
    pub activity_pruned_through: u64,
    pub link_count: u64,
}

The positions of a run store’s durable facts.

A run’s view is built from three kinds of durable fact, and each is tracked on its own: the lifecycle transitions and the bounded activity, which are feeds with cursors, and the operations linked to a run afterwards, which are an invalidation count. A consumer holds each separately, because lifecycle facts are never pruned while activity is bounded, a link changes a run’s view without being either, and none of them moves when the project’s operation history does. Two readings with equal positions in one epoch describe the same run facts.

Fields

epoch: Option<LineageId>

The lineage the run store is bound to, absent while no run store exists. Feed cursors are meaningful only within one epoch: a restore forks the run store to a new lineage, and its sequences continue from the backup, not from the store it was copied from.

lifecycle_head: u64

Newest lifecycle feed sequence, zero when the feed is empty.

activity_head: u64

Newest activity feed sequence ever assigned, zero when the feed is empty.

activity_pruned_through: u64

Highest activity sequence retention has removed; a cursor below it has a gap.

link_count: u64

How many operations were ever linked to a run in this epoch.

Links are append-only and each distinct operation is linked once, so the count only grows and a replayed link does not move it. It is an invalidation token, not a feed: it says that some run’s linked operations changed, not which, and a consumer that sees it change reads the runs it displays again. It promises no order of links and no resumable position.

Trait Implementations

impl Clone for RunFeedHeads

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for RunFeedHeads

impl Debug for RunFeedHeads

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

Formats the value using the given formatter.

impl Default for RunFeedHeads

fn default() -> Self

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for RunFeedHeads

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Eq for RunFeedHeads

impl PartialEq for RunFeedHeads

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl Serialize for RunFeedHeads

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

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for RunFeedHeads