Method Own

common/memory.h:1264–1269

struct Ownable {
 protected:
  Owned<const T> Own() const noexcept {
    static_assert(std::is_base_of_v<Data, T>, "T must be derived from Data");
    const T* const that = static_cast<const T*>(this);
    return Owned<const T>(
        Owner(Owner::Own(static_cast<const Data*>(that)->owner_)), that);
  }

  Owned<T> Own() noexcept {
    static_assert(std::is_base_of_v<Data, T>, "T must be derived from Data");