Method prepareRelScan

src/graph/on_disk_graph.cpp:206–217

TODO(Xiyang): since now we need to provide nbr info at prepare stage. It no longer make sense to have scanFwd&scanBwd. The direction has already been decided in this function.

// TODO(Xiyang): since now we need to provide nbr info at prepare stage. It no longer make sense to
// have scanFwd&scanBwd. The direction has already been decided in this function.
std::unique_ptr<NbrScanState> OnDiskGraph::prepareRelScan(const TableCatalogEntry& entry,
    oid_t relTableID, table_id_t nbrTableID, std::vector<std::string> relProperties,
    bool randomLookup) {
    auto& info = graphEntry.getRelInfo(entry.getTableID());
    auto state = std::make_unique<OnDiskGraphNbrScanState>(context, entry, relTableID,
        info.predicate, relProperties, randomLookup);
    state->nbrNodeTable = nodeIDToNodeTable.at(nbrTableID);
    if (nodeOffsetMaskMap != nullptr && nodeOffsetMaskMap->containsTableID(nbrTableID)) {
        state->nbrNodeMask = nodeOffsetMaskMap->getOffsetMask(nbrTableID);
    }
    return state;
}

Graph::EdgeIterator OnDiskGraph::scanFwd(nodeID_t nodeID, NbrScanState& state) {
    auto& onDiskScanState = dynamic_cast_checked<OnDiskGraphNbrScanState&>(state);