Weight & Capacity questions

[NathanielPrescott]

Hello!

I've been working to use DashMap in a personal cache that I am building. I have a couple questions related to capacity and weight.

Weight

I haven't seen any mention of adding weight per item in the issues or pull requests. I was wondering if you had thought about, were open to, or had previously tested with adding a weight attribute?

Capacity

Currently I've seen that when creating a DashMap we can specify the capacity. My understanding is that we are setting the initial capacity, which can then grow if you add more items than the current capacities limit. I was wonder if there has been discussion around setting a maximum capacity that will prevent the DashMap from growing past a specified amount.

Finally

My goal is to build a custom cache and was wondering if there were plans for the things I had listed or if I should fork your repo? Thank you for your time and this wonderful crate!

[zacknewman]

This is related to #311. You cannot rely on DashMap::capacity to ensure growth does not exceed a certain threshold without a re-allocation. Its behavior would ideally be changed such that it returns a lower bound of inserts that can occur without a re-allocation. With that alone, it is quite easy to implement custom logic or a newtype that inserts iff len < capacity. Of course having a constructor that ensures this out-of-the-box would be nice too.

[NathanielPrescott]

Gotcha, thanks for letting me know about the capacity! Think I'll just build this from the ground up after trying a few other caches and realizing my needs.