rebuild

Source: crates/lvcs/src/runtime/replay.rs.

/// Why [`rebuild`] returned no actor.
#[derive(Debug, Clone, PartialEq, Eq)]
pub(crate) enum RebuildError {
    /// Entry `index` belongs to `actor`, not the actor being rebuilt.
    Foreign {
        /// Zero-based index of the entry.
        index: u64,
        /// The actor the entry belongs to.
        actor: ActorId,
    },
    /// Entry `index` names `incarnation`, older than the `newest` one
    /// before it.
    OutOfOrder {
        /// Zero-based index of the entry.
        index: u64,
        /// The incarnation the entry names.
        incarnation: u64,
        /// The newest incarnation an earlier entry named.
        newest: u64,
    },
    /// Replay differed from the journal, so the rebuilt context can't be
    /// trusted.
    Diverged(Divergence),
}

/// Restart a router, mirror, or workspace machine from its own journal
/// entries (design §2 supervision, decision 56).
///
/// Feed `fresh`, a newly constructed machine, every entry for its
/// `(hooks.kind, key)` from all its earlier incarnations, in journal order,
/// and discard the outputs. Incarnations may skip numbers but never go back.
/// Spawn the result under the id `Incarnations::next` mints. Document
/// actors restart from their saves instead.
///
/// # Errors
///
/// [`RebuildError::Foreign`] when an entry belongs to another actor,
/// [`RebuildError::OutOfOrder`] when an entry's incarnation is older than an
/// earlier entry's, and [`RebuildError::Diverged`] when replay differs from
/// the journal.
pub(crate) fn rebuild<M, E, O, C, I>(
    fresh: M,
    hooks: &Hooks<M, O, C>,
    key: &str,
    entries: I,
) -> Result<M, RebuildError>
where
    M: sml::Machine<E>,
    C: PartialEq + Debug,
    I: IntoIterator<Item = JournalEntry<E, C>>,