Proposal: storage type allocation signal

[pgruenbacher]

It'd be nice if we had a signal that was published from registry

like so:
b9d10ad

Allows for logging warnings if storage allocation occurs during runtime after the registry has already been reserved.

void handleStorageAllocated(entt::id_type id) {

  if (auto t = entt::resolve(id)) {
    SPDLOG_ERROR("Allocated storage? {}", t.info().name());
  } else {
    SPDLOG_ERROR("Allocated storage? {}", id);
  }
}

registry.on_storage_allocated().connect<&handleStorageAllocated>();

[pgruenbacher]

The reason why this would be useful is to catch multi-threading issues by logging when a non-reserved storage is being allocated, since this would affect if a different thread was reading from the registry.

[pgruenbacher]

it'd be good if we had a signal if groups are emplaced as well

[skypjack]

The reason why this would be useful is to catch multi-threading issues by logging when a non-reserved storage is being allocated

I think a way to have it is with a custom allocator actually.
Another approach is with a mixin that logs the capacity and checks it on use to know if it changed in the meantime (i.e. after an emplace).

It's not that easy to have it in the registry instead, because it is not the registry that allocates.
Instead, we should add a signal to the storage itself. However, the storage does not support signals on its own. We use a mixin to add signals on top of storage types.
This makes the whole implementation super tricky.

If it's only a matter of logging, I'd rather go with a mixin or a custom allocator. I don't think I'll ever be able to implement this in a nice and clean way. 🤔

[pgruenbacher]

well.. it's not the storage that's doing allocating here, it's just the storage pools container that's being allocated which I'm concerned about, since the dense_map isn't thread safe when it's being emplaced with another pool.

[skypjack]

Yeah, however the problem is literally the same.
Neither the map nor the storage or the sparse set send or can send messages without a major redesign that I don't think needs to be done.
This opens up options for using mixins or a custom allocator. Do you see any others that I don't see? I'm still jet-lagged, so it wouldn't surprise me. 😅