void Version::ForEachOverlapping()

in db/version_set.cc [278:321]

• 36 lines of code
• 12 McCabe index (conditional complexity)

void Version::ForEachOverlapping(Slice user_key, Slice internal_key,
                                 void* arg,
                                 bool (*func)(void*, int, FileMetaData*)) {
  // TODO(sanjay): Change Version::Get() to use this function.
  const Comparator* ucmp = vset_->icmp_.user_comparator();

  // Search level-0 in order from newest to oldest.
  std::vector<FileMetaData*> tmp;
  tmp.reserve(files_[0].size());
  for (uint32_t i = 0; i < files_[0].size(); i++) {
    FileMetaData* f = files_[0][i];
    if (ucmp->Compare(user_key, f->smallest.user_key()) >= 0 &&
        ucmp->Compare(user_key, f->largest.user_key()) <= 0) {
      tmp.push_back(f);
    }
  }
  if (!tmp.empty()) {
    std::sort(tmp.begin(), tmp.end(), NewestFirst);
    for (uint32_t i = 0; i < tmp.size(); i++) {
      if (!(*func)(arg, 0, tmp[i])) {
        return;
      }
    }
  }

  // Search other levels.
  for (int level = 1; level < config::kNumLevels; level++) {
    size_t num_files = files_[level].size();
    if (num_files == 0) continue;

    // Binary search to find earliest index whose largest key >= internal_key.
    uint32_t index = FindFile(vset_->icmp_, files_[level], internal_key);
    if (index < num_files) {
      FileMetaData* f = files_[level][index];
      if (ucmp->Compare(user_key, f->smallest.user_key()) < 0) {
        // All of "f" is past any data for user_key
      } else {
        if (!(*func)(arg, level, f)) {
          return;
        }
      }
    }
  }
}