Struct GroupStateSnapshot 

pub struct GroupStateSnapshot {
    pub v: u8,
    pub group_id: ConversationId,
    pub openmls_storage_version: u16,
    pub snapshot_created_at_ms: u64,
    pub entries: Vec<GroupSnapshotEntry>,
}

[CR-7] Portable snapshot of an MLS group’s OpenMLS state.

Produced by [Conversation::export_state_snapshot] on one device, consumed by [MessagingClient::import_state_snapshot] on another to re-attach to the same group without re-Welcoming. The receiver MUST be the same user identity (the linking-flow QR handshake or recovery mnemonic provides that).

What’s in: every OpenMLS storage entry whose key references this group’s group_id. Trees, contexts, transcript hashes, message secrets, epoch keys — everything MlsGroup::load needs to reconstruct the live group object.

What’s out: signature keypairs (recovered devices ALWAYS get a fresh signing key per [recovery.md §recovery on a new device]); leaf-keyed encryption keypairs for other leaves (those don’t have the group_id in their key by definition); pending KeyPackages (per-device; receiver generates fresh ones on first publish).

Forward secrecy note: this snapshot exposes the exporter’s view of past epoch secrets for this group. That’s intentional for the linking + DG-recovery use cases (same user, trusted handover via QR / mnemonic). It is NOT used for peer-conversation history transfer — that goes through HPKE-sealed AppEvent re-shares per umbrella §15.6. Hosts MUST ensure callers of export_state_snapshot are authenticated to the user’s intent.

Fields

v: u8

Format version. Bumped on incompatible CBOR-shape changes.

group_id: ConversationId

Group id this snapshot describes. Sanity-checked on import — passing a snapshot for the wrong group is an error.

openmls_storage_version: u16

OpenMLS storage-provider version at export time. Import refuses mismatched versions outright (no automatic forward/back compat).

snapshot_created_at_ms: u64

Wall-clock ms at export. Informational; receivers can warn on stale snapshots but the SDK does not act on it.

entries: Vec<GroupSnapshotEntry>

(raw_storage_key, raw_storage_value) pairs lifted from the exporter’s MemoryStorage. The receiver replays them into its own provider via import_entries.

Implementations

impl GroupStateSnapshot

pub fn encode(&self) -> Result<Vec<u8>>

CBOR-encode the snapshot. Hard-cap-rejects oversize blobs; logs a warning at the soft cap.

pub fn decode(bytes: &[u8]) -> Result<Self>

Decode a CBOR-encoded snapshot. Rejects unknown v and oversize inputs.

Trait Implementations

impl Clone for GroupStateSnapshot

fn clone(&self) -> GroupStateSnapshot

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for GroupStateSnapshot

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for GroupStateSnapshot

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for GroupStateSnapshot

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

where __S: Serializer,

Serialize this value into the given Serde serializer.