Function GetOneFlattened

cpp/src/arrow/type.h:2273–2276

  /// child's null bitmap is ANDed with its ancestors'
  template <typename T>
  Result<GetType<T>> GetOneFlattened(const T& root, MemoryPool* pool = NULLPTR) const {
    ARROW_ASSIGN_OR_RAISE(auto match, FindOne(root));
    return match.GetFlattened(root, pool);
  }

  /// \brief Get the single child matching this FieldRef.
  /// Return nullptr if none match, emit an error if multiple match.