naming inconsistency between "ranking" and "interval"

[matthme]

Provided that I understand the code correctly, the term ranking is sometimes referred to the ranking of an entry and sometimes to a ranking interval which is confusing.

Here a ranking is an arbitrary integer used to rank entries:
lib.rs:28

    pub fn create_entry_ranking(
        &self,
        entry_hash: EntryHash,
        ranking: i64,
        tag: Option<SerializedBytes>,
    ) -> ExternResult<()>

According to the code below, the leaf of the path is a then a ranking interval, not a ranking.
lib.rs:178:

    fn ranking_interval(&self, ranking: i64) -> i64 {
        ranking / (self.index_interval as i64)
    }

    fn get_ranking_path(&self, ranking: i64) -> Path {
        Path::from(format!(
            "{}.{}",
            self.root_path_str(),
            self.ranking_interval(ranking)
        ))
    }

A cursor has a from_ranking attribute:

types.rs:18:

#[derive(Serialize, Deserialize, Debug, Clone)]
pub struct GetRankingCursor {
    pub from_ranking: i64,
}

However in initial_interval_index() the from_ranking attribute of the cursor is compared to the ranking interval (i.e. ranking divided by index_interval) in order to get the initial interval index:

lib.rs:235

fn initial_interval_index(
    interval_paths: &BTreeMap<i64, Path>,
    direction: GetRankingDirection,
    maybe_cursor: Option<GetRankingCursor>,
) -> usize {
    match maybe_cursor {
        None => match direction {
            GetRankingDirection::Ascendent => 0,
            GetRankingDirection::Descendent => interval_paths.len() - 1,
        },
        Some(cursor) => {
            let ordered_keys: Vec<i64> = interval_paths.keys().into_iter().cloned().collect();
            for i in 0..(interval_paths.len() - 1) {
                if ordered_keys[i] <= cursor.from_ranking //      <<<<<<<<<<<      HERE (line 248)     <<<<<<<<<<<
                    && cursor.from_ranking < ordered_keys[i + 1]
                {
                    return i;
                }
            }
            return 0;
        }
    }
}

I would propose to either rename from_ranking to from_ranking_interval or actually compare rankings with each other in line 248 by multiplying ordered_keys[i] and ordered_keys[ i+1 ] with self.index_interval. The latter is probably more intuitive for users of the module since they can provide a ranking instead of a ranking interval when specifying a cursor.