Struct LfsMedia 

pub struct LfsMedia { /* private fields */ }

The LFS-media alkblobs::LivenessSource — the second alkgit-owned liveness source (substrate.md §GC source 2; ADR-022 §4): the pointer-lifecycle rows as the media family’s live set, a mark consult that reads the rows (no graph walk) and an arbitration consult that answers from the mark’s index. See the module docs’ LFS section for the walk-not-walk posture, the invalidation decision, and the cross-process residual.

Implementations

impl LfsMedia

pub fn new(rows: Arc<dyn LfsRows>, writes: Arc<AtomicU64>) -> Arc<Self>

The source over the rows surface and the composition’s shared assert counter (the VersionedLfsRows wrapper bumps the same counter per committed assert through it — the bump-after-commit half of the epoch discipline). Construct within the running runtime (the assembly does): the constructor captures Handle::current() for the mark consult’s bridge.

pub fn register(self: &Arc<Self>, store: &Store) -> Result<Registration, Error>

Register the source with the store — the live-shared seam (Store::register_liveness_source; the composition entry’s second registration leg, the fail-safe default ADR-022 §6: an unregistered media source lets sweeps eat referenced media on the first mixed-feature deployment). Registration once, at construction; the returned token is deregister-at-most-once and is the composition’s to keep.

pub fn keys_builds(&self) -> u64

How many mark consults have run — the rebuild-per-mark posture’s pin (no fingerprint memo: every mark consult re-reads the rows; the arbitration consult never triggers one).

Trait Implementations

impl LivenessSource for LfsMedia

Available on crate feature lfs only.

fn live_keys(&self) -> Vec<Key>

The mark-time consult — rebuild-per-mark (the module docs’ LFS section; the row read is the whole walk). A failed rows read answers empty with the memo untouched: the staged candidates arbitrate against the stale index (the previous mark’s) — conservative for keys live at that build, and the next mark corrects. The alternative postures (blocking or panicking the sweep’s mark) are worse.

fn contains(&self, key: &Key) -> bool

The delete-time arbitration consult — under the store’s arbitration lock, quick, indexed, never blocking (no bridge, no reads, no recompute):

• an index hit answers exactly (true — the key was live at the last mark);
• a cold (never-marked) source answers true — the safe default (unknown is live); direct deletes under it refuse (alkblobs::Error::GcRefuse, the ADR-012 §6.4 flow);
• an index miss after a moved assert counter answers true too — a row may have landed since the build (unknown is live): the candidate cancels and resolves on the next mark’s rebuild, one delayed sweep.