Struct ProvenanceHeader 

#[repr(C)]
pub struct ProvenanceHeader {
    pub node_type: ProvNodeType,
    pub node_id: u64,
    pub relations: [ProvRelation; 4],
    pub overflow_ref: Option<u64>,
    pub prov_timestamp: HlcTimestamp,
    pub plan_id: Option<u64>,
}

PROV-O attribution metadata attached to a message envelope.

• Absent: MessageEnvelope::provenance == None - 1 byte overhead.
• Present: ~size_of::<ProvenanceHeader>() bytes inline (verified by test [tests::test_provenance_header_size]). The spec notes a ~88 byte target; actual size depends on natural alignment and is asserted in the test module.
• With >4 relations: one extra cache line referenced by overflow_ref (caller owns that off-band record).

Fields

node_type: ProvNodeType

Classification of the node this header describes.

node_id: u64

Globally unique PROV node ID (Entity/Activity/Agent/Plan).

relations: [ProvRelation; 4]

Inline PROV relations. Empty slots have kind == ProvRelationKind::None. When more than 4 relations are needed, callers set overflow_ref.

overflow_ref: Option<u64>

Optional off-band pointer to an extended relations record. None when all relations fit inline.

prov_timestamp: HlcTimestamp

HLC timestamp of the PROV event (generation / attribution time).

plan_id: Option<u64>

Optional Plan ID when this activity is executed under a Plan.

Implementations

impl ProvenanceHeader

pub const fn new(node_type: ProvNodeType, node_id: u64) -> Self

Construct a header with all empty relation slots.

pub fn relation_count(&self) -> usize

Number of populated inline relations.

pub const fn has_overflow(&self) -> bool

Whether any overflow relations are referenced.

pub fn iter_relations(&self) -> impl Iterator<Item = &ProvRelation>

Iterate over the populated inline relations.

pub fn find_relation(&self, kind: ProvRelationKind) -> Option<&ProvRelation>

Find the first relation of a given kind, if present inline.

pub fn validate(&self) -> Result<(), ProvenanceError>

Validate structural invariants that are cheap to check.

• node_id must be non-zero (0 is reserved as “unset”).
• At most one self-loop is allowed (would indicate a cycle).
• Relation kinds must be consistent with the declared node_type when they have an expected source type.

Trait Implementations

impl Archive for ProvenanceHeader

where ProvNodeType: Archive, u64: Archive, [ProvRelation; 4]: Archive, Option<u64>: Archive, HlcTimestamp: Archive,

type Archived = ArchivedProvenanceHeader

The archived representation of this type.

type Resolver = ProvenanceHeaderResolver

The resolver for this type. It must contain all the additional information from serializing needed to make the archived type from the normal type.

unsafe fn resolve( &self, pos: usize, resolver: Self::Resolver, out: *mut Self::Archived, )

Creates the archived version of this value at the given position and writes it to the given output.

impl Clone for ProvenanceHeader

fn clone(&self) -> ProvenanceHeader

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ProvenanceHeader

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

Formats the value using the given formatter.

impl Default for ProvenanceHeader

fn default() -> Self

Returns the “default value” for a type.

impl<__D: Fallible + ?Sized> Deserialize<ProvenanceHeader, __D> for Archived<ProvenanceHeader>

where ProvNodeType: Archive, Archived<ProvNodeType>: Deserialize<ProvNodeType, __D>, u64: Archive, Archived<u64>: Deserialize<u64, __D>, [ProvRelation; 4]: Archive, Archived<[ProvRelation; 4]>: Deserialize<[ProvRelation; 4], __D>, Option<u64>: Archive, Archived<Option<u64>>: Deserialize<Option<u64>, __D>, HlcTimestamp: Archive, Archived<HlcTimestamp>: Deserialize<HlcTimestamp, __D>,

fn deserialize( &self, deserializer: &mut __D, ) -> Result<ProvenanceHeader, __D::Error>

Deserializes using the given deserializer

impl PartialEq for ProvenanceHeader

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<__S: Fallible + ?Sized> Serialize<__S> for ProvenanceHeader

where ProvNodeType: Serialize<__S>, u64: Serialize<__S>, [ProvRelation; 4]: Serialize<__S>, Option<u64>: Serialize<__S>, HlcTimestamp: Serialize<__S>,

fn serialize(&self, serializer: &mut __S) -> Result<Self::Resolver, __S::Error>

Writes the dependencies for the object and returns a resolver that can create the archived type.

impl Copy for ProvenanceHeader

impl Eq for ProvenanceHeader

impl StructuralPartialEq for ProvenanceHeader