Iter for StorageVec

[bitzoic]

An internal contributor has requested the Iter trait be implemented for StorageVec

[kostekIV]

Hi, wouldnt there be a problem with function purity? Iterator::next is pure but unless the StorageVec would be preloaded as VecIter the next would require some reads. Asking out of curiosity :)

So implementation that would look like this is not feasible unless there would be a new Iterator trait for Storage structs:

pub struct StorageVecIter<T> {
    storage_vec: StorageKey<StorageVec<T>>,
    vec_len: u64,
    index: u64,
}

impl<T> Iterator for StorageVecIter<T> {
    type Item = StorageKey<T>;

    fn next(ref mut self) -> Option<Self::Item> {
        if self.index >= vec_len {
            return None
        }

        self.index += 1;
        self.storage_vec.get(self.index - 1)
    }
}