Struct StateRevision 

pub struct StateRevision {
    pub id: StateId,
    pub resource: String,
    pub content: String,
    pub content_id: StateId,
    pub parent_id: Option<StateId>,
    pub sequence: u64,
    pub authority: String,
    pub timestamp_ms: u64,
    pub metadata: BTreeMap<String, Value>,
}

An immutable, resource-scoped historical state.

A revision is a revision of a resource. Two resources holding identical content are distinct revisions, and a resource that returns to a value it previously held records a new revision rather than resurrecting the old one.

Two identities, deliberately

id is the revision identity: what distinguishes one historical occurrence from another. It is computed over the resource, the content, the parent and a per-resource sequence, so content equality is not identity.

content_id is the content identity, the hash of the canonical content alone. It is what makes a revision verifiable against its own bytes, and it is what deduplicates content comparisons — two revisions of the same state share a content_id and differ in id.

Conflating these two was the defect the identity contract found: a revert produced a revision whose identity already existed, so committing it overwrote the earlier one and closed a cycle in the parent chain.

Fields

id: StateId

Revision identity — resource, content, parent and sequence.

resource: String

The resource this is a revision of.

content: String

Canonical JSON representation (representation-sensitive)

content_id: StateId

Content identity — the hash of content alone.

parent_id: Option<StateId>

Parent revision id. None only for a resource’s first revision.

sequence: u64

Position in this resource’s history. Strictly increasing, never reused.

authority: String

Authority that produced this revision

timestamp_ms: u64

Timestamp when revision was created (informational only, not used for ordering)

metadata: BTreeMap<String, Value>

Metadata (preservable with state)

Implementations

impl StateRevision

pub fn initial(resource: String, content: String, authority: String) -> Self

Create a resource’s first revision.

pub fn child(content: String, parent: &StateRevision, authority: String) -> Self

Create a revision descending from parent, on the parent’s resource.

pub fn at( resource: String, content: String, parent_id: Option<StateId>, sequence: u64, authority: String, ) -> Self

Create a revision at an explicit position in a resource’s history.

pub fn verify_integrity(&self) -> bool

Verify that both identities match what they are computed from.

pub fn parent(&self) -> Option<&StateId>

Get parent id if this is not a resource’s first revision.

pub fn equals(&self, other: &StateRevision) -> bool

Whether two revisions are the same revision.

Revision identity, not content equality: two revisions of the same state on the same resource are not equal.

pub fn same_content_as(&self, other: &StateRevision) -> bool

Whether two revisions hold the same state, regardless of where in history they occur.

Trait Implementations

impl Clone for StateRevision

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for StateRevision

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for StateRevision

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for StateRevision

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

where __S: Serializer,

Serialize this value into the given Serde serializer.