Method NestedSelector

cpp/src/arrow/type.cc:1638–1639

  using Util = NestedSelectorUtil;

  explicit NestedSelector(const std::vector<std::shared_ptr<T>>& children)
      : parent_or_children_(&children) {}
  explicit NestedSelector(const T& parent) : parent_or_children_(&parent) {}
  explicit NestedSelector(std::shared_ptr<T> parent)
      : owned_parent_(std::move(parent)), parent_or_children_(owned_parent_.get()) {}