Function spawn

nodedb/src/control/array_sync/gc_task.rs:42–73

Spawn the GC task and return a [`JoinHandle`]. `array_snapshot_hlcs` is the shared map that `ArrayFanout`'s `snapshot_trigger` reads to know the current GC boundary per array. The GC task writes the updated `snapshot_hlc` after each successful compaction run.

(
    op_log: Arc<OriginOpLog>,
    snapshots: Arc<OriginSnapshotStore>,
    ack_registry: Arc<ArrayAckRegistry>,
    array_snapshot_hlcs: Arc<RwLock<HashMap<String, Hlc>>>,
    shutdown: Arc<Shutdown

/// The GC task writes the updated `snapshot_hlc` after each successful
/// compaction run.
pub fn spawn(
    op_log: Arc<OriginOpLog>,
    snapshots: Arc<OriginSnapshotStore>,
    ack_registry: Arc<ArrayAckRegistry>,
    array_snapshot_hlcs: Arc<RwLock<HashMap<String, Hlc>>>,
    shutdown: Arc<ShutdownWatch>,
    interval: Duration,
) -> Option<JoinHandle<()>> {
    let Ok(handle) = tokio::runtime::Handle::try_current() else {
        debug!("array_gc_task: no tokio runtime; skipping spawn (test or non-async context)");
        return None;
    };
    Some(handle.spawn(async move {
        let mut shutdown_rx: ShutdownReceiver = shutdown.subscribe();
        loop {
            tokio::select! {
                _ = tokio::time::sleep(interval) => {
                    run_gc(
                        &op_log,
                        &snapshots,
                        &ack_registry,
                        &array_snapshot_hlcs,
                    );
                }
                _ = shutdown_rx.wait_cancelled() => {
                    debug!("array_gc_task: shutdown received — exiting");
                    return;
                }
            }
        }
    }))
}

/// Execute one GC pass across all known arrays.
fn run_gc(