Struct GraphHeader 

pub struct GraphHeader {
    pub version: u32,
    pub node_count: usize,
    pub edge_count: usize,
    pub string_count: usize,
    pub file_count: usize,
    pub timestamp: u64,
    pub config_provenance: Option<ConfigProvenance>,
    pub plugin_versions: HashMap<String, String>,
    pub fact_epoch: u64,
}

Header for persisted graph files.

The header provides metadata about the graph for validation and efficient loading.

Fields

version: u32

Format version (for compatibility checking)

node_count: usize

Number of nodes in the graph

edge_count: usize

Number of edges in the graph

string_count: usize

Number of interned strings

file_count: usize

Number of registered files

timestamp: u64

Timestamp when graph was saved (unix epoch seconds)

config_provenance: Option<ConfigProvenance>

Configuration provenance - records which config was used to build this graph.

plugin_versions: HashMap<String, String>

Plugin versions used to build this graph (plugin_id → version).

Tracks which language plugin versions were active during indexing. Used to detect stale indexes when plugin versions change.

fact_epoch: u64

Monotonic fact-layer epoch stamped at save time (Phase 1+).

Strictly increases across successive saves of the same snapshot file, including across process restarts: the writer reads the existing header (if any) before stamping and computes max(prev_epoch + 1, SystemTime::now().as_secs()).

Defaulted to 0 for V7 snapshots and for GraphHeader::new / with_provenance constructors. The epoch is stamped by the Phase 1 V8 writer (P1U06); this unit only introduces the field and accessors.

Format: plain u64, serde-default 0 so postcard deserialization of older headers that did not carry the field continues to succeed.

Implementations

impl GraphHeader

pub fn new( node_count: usize, edge_count: usize, string_count: usize, file_count: usize, ) -> Self

Creates a new graph header with the given counts.

pub fn with_provenance( node_count: usize, edge_count: usize, string_count: usize, file_count: usize, provenance: ConfigProvenance, ) -> Self

Creates a new graph header with config provenance.

pub fn with_provenance_and_plugins( node_count: usize, edge_count: usize, string_count: usize, file_count: usize, provenance: ConfigProvenance, plugin_versions: HashMap<String, String>, ) -> Self

Creates a new graph header with config provenance and plugin versions.

pub fn provenance(&self) -> Option<&ConfigProvenance>

Returns the config provenance if available.

pub fn has_provenance(&self) -> bool

Checks if the graph was built with tracked config provenance.

pub fn plugin_versions(&self) -> &HashMap<String, String>

Returns the plugin versions used to build this graph.

pub fn set_plugin_versions(&mut self, versions: HashMap<String, String>)

Sets the plugin versions for this graph header.

pub fn fact_epoch(&self) -> u64

Returns the monotonic fact-layer epoch stamped on this header.

Returns 0 for headers created via new / with_provenance / with_provenance_and_plugins before the Phase 1 writer stamps a real epoch (P1U06), and for legacy V7 snapshots loaded through the backwards-read path (P1U07).

pub fn set_fact_epoch(&mut self, epoch: u64)

Sets the monotonic fact-layer epoch on this header.

Intended for use by the Phase 1 V8 writer (P1U06), which computes the epoch via a FactEpochClock helper and stamps it immediately before serialization. Also used by tests.

Trait Implementations

impl Clone for GraphHeader

fn clone(&self) -> GraphHeader

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for GraphHeader

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for GraphHeader

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for GraphHeader

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

where __S: Serializer,

Serialize this value into the given Serde serializer.