rocksdb::Status Database::Keys()

in src/storage/redis_db.cc [249:316]
61 lines of code
24 McCabe index (conditional complexity)

rocksdb::Status Database::Keys(engine::Context &ctx, const std::string &prefix, const std::string &suffix_glob,
                               std::vector<std::string> *keys, KeyNumStats *stats) {
  uint16_t slot_id = 0;
  std::string ns_prefix;
  if (namespace_ != kDefaultNamespace || keys != nullptr) {
    if (storage_->IsSlotIdEncoded()) {
      ns_prefix = ComposeNamespaceKey(namespace_, "", false);
      if (!prefix.empty()) {
        PutFixed16(&ns_prefix, slot_id);
        ns_prefix.append(prefix);
      }
    } else {
      ns_prefix = AppendNamespacePrefix(prefix);
    }
  }

  uint64_t ttl_sum = 0;
  auto iter = util::UniqueIterator(ctx, ctx.GetReadOptions(), metadata_cf_handle_);

  while (true) {
    ns_prefix.empty() ? iter->SeekToFirst() : iter->Seek(ns_prefix);
    for (; iter->Valid(); iter->Next()) {
      if (!ns_prefix.empty() && !iter->key().starts_with(ns_prefix)) {
        break;
      }
      auto [_, user_key] = ExtractNamespaceKey(iter->key(), storage_->IsSlotIdEncoded());
      if (!util::StringMatch(suffix_glob, user_key.ToString().substr(prefix.size()))) {
        continue;
      }
      Metadata metadata(kRedisNone, false);
      auto s = metadata.Decode(iter->value());
      if (!s.ok()) continue;
      if (metadata.Expired()) {
        if (stats) stats->n_expired++;
        continue;
      }
      if (stats) {
        int64_t ttl = metadata.TTL();
        stats->n_key++;
        if (ttl != -1) {
          stats->n_expires++;
          if (ttl > 0) ttl_sum += ttl;
        }
      }
      if (keys) {
        keys->emplace_back(user_key.ToString());
      }
    }

    if (auto s = iter->status(); !s.ok()) {
      return s;
    }

    if (!storage_->IsSlotIdEncoded()) break;
    if (prefix.empty()) break;
    if (++slot_id >= HASH_SLOTS_SIZE) break;

    ns_prefix = ComposeNamespaceKey(namespace_, "", false);
    PutFixed16(&ns_prefix, slot_id);
    ns_prefix.append(prefix);
  }

  if (stats && stats->n_expires > 0) {
    stats->avg_ttl = ttl_sum / stats->n_expires / 1000;
  }

  return rocksdb::Status::OK();
}