Method GetFragmentsImpl

cpp/src/arrow/dataset/file_base.cc:307–346

}

Result<FragmentIterator> FileSystemDataset::GetFragmentsImpl(
    compute::Expression predicate) {
  if (predicate == compute::literal(true)) {
    // trivial predicate; skip subtree pruning
    return MakeVectorIterator(FragmentVector(fragments_.begin(), fragments_.end()));
  }

  std::vector<int> fragment_indices;

  std::vector<compute::Expression> predicates{predicate};
  RETURN_NOT_OK(subtrees_->forest.Visit(
      [&](Forest::Ref ref) -> Result<bool> {
        if (auto fragment_index =
                std::get_if<int>(&subtrees_->fragments_and_subtrees[ref.i])) {
          fragment_indices.push_back(*fragment_index);
          return false;
        }

        const auto& subtree_expr =
            std::get<compute::Expression>(subtrees_->fragments_and_subtrees[ref.i]);
        ARROW_ASSIGN_OR_RAISE(auto simplified,
                              SimplifyWithGuarantee(predicates.back(), subtree_expr));

        if (!simplified.IsSatisfiable()) {
          return false;
        }

        predicates.push_back(std::move(simplified));
        return true;
      },
      [&](Forest::Ref ref) { predicates.pop_back(); }));

  std::sort(fragment_indices.begin(), fragment_indices.end());

  FragmentVector fragments(fragment_indices.size());
  std::transform(fragment_indices.begin(), fragment_indices.end(), fragments.begin(),
                 [this](int i) { return fragments_[i]; });

  return MakeVectorIterator(std::move(fragments));
}

Status FileWriter::Write(RecordBatchReader* batches) {
  while (true) {