Enum SealedState 

#[non_exhaustive]
pub enum SealedState {
    Empty,
    Opens,
    Foreign,
    KeyDamaged,
}

What the record key an MLS store holds makes of the sealed records in a protocol-state store.

The engine seals protocol state under a key it keeps in the MLS store, and a record that does not open is deleted as the restore reaches it: a record nothing can read is a loss to settle, not a read to retry. That is right for one damaged record and wrong for a store sealed under another identity’s key, where the first restore deletes the queued and parked messages of an identity that is merely somewhere else. This is the question to ask before the engine is handed the pair.

It is asked of the categories the engine seals. The telemetry queue is sealed under the same key and is not examined: a batch that does not open is the uploader’s to drop, and no message is lost with it.

The records alone cannot tell another identity’s state from this identity’s state after the engine regenerated a damaged record key. The launch that regenerates it cannot delete everything sealed under the lost key (documents are read when they are opened, and each restore walk stops at its delete allowance), so every later launch finds records that open under no key the MLS store holds, and this answers Foreign. Open the two stores with crate::FileStorePair, which records which MLS store a state store belongs with and asks the records only of a state store never bound.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Empty

No record in any category the engine seals.

Opens

A sealed record opens under the MLS store’s record key: the two stores belong together.

Foreign

Sealed records exist, in no category does one of those tried open, and the MLS store holds a usable record key or none at all: they were sealed under another key, another identity’s or one this identity lost and replaced (see above). The engine deletes the ones its restore reads, queued and parked messages among them.

KeyDamaged

Sealed records exist and the MLS store’s record key is damaged, so nothing will open them again, whoever sealed them. Refusing the pair saves nothing. The engine generates a new key and settles what its restore reads as failed, which is how the application learns which messages were lost.

Trait Implementations

impl Clone for SealedState

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 SealedState

impl Debug for SealedState

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

Formats the value using the given formatter.

impl Eq for SealedState

impl PartialEq for SealedState

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for SealedState