Method setSecondaryEngine

pj_datastore/src/plugin_data_host.cpp:2066–2079

}

void DatastoreSourceWriteHost::setSecondaryEngine(DataEngine* secondary) {
  // Wire the secondary engine for streaming pause/resume lockstep. Mirroring
  // is bidirectional: the active WriteCore mirrors to whichever engine is
  // the other one. Called once by the streaming runtime host right after
  // construction; passing nullptr disables mirroring.
  state_->secondary_engine = secondary;
  // Called once right after construction, before any ingest worker runs, so
  // mutating the live core's mirror target in place is safe (no concurrent reader
  // yet); load() merely unwraps the atomic.
  if (auto core = state_->core.load(std::memory_order_acquire)) {
    // Whichever direction we're currently pointed at, mirror to the other.
    core->secondary_engine = (&core->engine == state_->primary_engine) ? secondary : state_->primary_engine;
  }
}

DatastoreParserWriteHost::DatastoreParserWriteHost(DataEngine& engine, TopicHandle topic)
    : state_(std::make_unique<DatastoreParserWriteHostState>(engine, topic)) {}