SNMALLOC_SLOW_PATH decltype()

in src/mem/localalloc.h [116:163]

• 30 lines of code
• 6 McCabe index (conditional complexity)

    SNMALLOC_SLOW_PATH decltype(auto) lazy_init(Action action, Args... args)
    {
      SNMALLOC_ASSERT(core_alloc == nullptr);
      if constexpr (!SharedStateHandle::Options.LocalAllocSupportsLazyInit)
      {
        SNMALLOC_CHECK(
          false &&
          "lazy_init called on an allocator that doesn't support lazy "
          "initialisation");
        // Unreachable, but needed to keep the type checker happy in deducing
        // the return type of this function.
        return static_cast<decltype(action(core_alloc, args...))>(nullptr);
      }
      else
      {
        // Initialise the thread local allocator
        if constexpr (SharedStateHandle::Options.CoreAllocOwnsLocalState)
        {
          init();
        }

        // register_clean_up must be called after init.  register clean up may
        // be implemented with allocation, so need to ensure we have a valid
        // allocator at this point.
        if (!post_teardown)
          // Must be called at least once per thread.
          // A pthread implementation only calls the thread destruction handle
          // if the key has been set.
          SharedStateHandle::register_clean_up();

        // Perform underlying operation
        auto r = action(core_alloc, args...);

        // After performing underlying operation, in the case of teardown
        // already having begun, we must flush any state we just acquired.
        if (post_teardown)
        {
#ifdef SNMALLOC_TRACING
          std::cout << "post_teardown flush()" << std::endl;
#endif
          // We didn't have an allocator because the thread is being torndown.
          // We need to return any local state, so we don't leak it.
          flush();
        }

        return r;
      }
    }