Function FindOrInsert

be/src/util/container-util.h:195–201

template <typename K, typename V>
V* FindOrInsert(std::map<K,V>* m, const K& key, const V& default_val) {
  typename std::map<K,V>::iterator it = m->find(key);
  if (it == m->end()) {
    it = m->insert(std::make_pair(key, default_val)).first;
  }
  return &it->second;
}

template <typename K, typename V>
V* FindOrInsert(std::unordered_map<K,V>* m, const K& key, const V& default_val) {