`BoundedBTreeMap` equivalent for `StorageMap`?

Question

I'd like to set an upper limit on the size of a storage map. Is there a data structure that supports this check within its methods? Or has anyone defined their own wrapper data structure that performs these checks on each insertion?

Answer 1

If you want a hard limit, then you have to create a wrapper.
The MaxValues on StorageMap and CountedStorageMap are only a soft limit for PoV estimations.

I don't know of any implementations of this. Not sure what you are trying to do either.

Answer 2

There is a counted storage map: doc implementation

pub struct CountedStorageMap<
 Prefix,
 Hasher,
 Key, 
 Value, 
 QueryKind = OptionQuery,
 OnEmpty = GetDefault,
 MaxValues = GetDefault
>(/* private fields */);