Function Release

common/memory.h:646–661

  }

  void Release(T** ptr, Owner* owner) noexcept {
    if (ptr_ == nullptr) {
      *ptr = nullptr;
      return;
    }
    PreRelease();
    *ptr = std::exchange(ptr_, nullptr);
    if (arena_ == 0) {
      owner->ptr_ = reinterpret_cast<uintptr_t>(
                        common_internal::MakeDeletingReferenceCount(*ptr)) |
                    common_internal::kMetadataOwnerReferenceCountBit;
    } else {
      owner->ptr_ = reinterpret_cast<uintptr_t>(arena()) |
                    common_internal::kMetadataOwnerArenaBit;
    }
  }

  T* ptr_ = nullptr;
  // Potentially tagged pointer to `google::protobuf::Arena`. The tag is used to determine