Method lookup_prefix

nodedb/src/engine/kv/index.rs:206–218

Prefix lookup: match on leading fields only. E.g., on a `(region, status)` index, `lookup_prefix(&[b"us-east"])` returns all keys where `region = "us-east"` regardless of status. Uses `starts_with()` on the B-Tree range to avoid false matches from the `0xFF` upper-bound trick, which breaks if field values contain bytes >= `0xFF`.

(&self, prefix_values: &[&[u8]])

    /// the `0xFF` upper-bound trick, which breaks if field values contain
    /// bytes >= `0xFF`.
    pub fn lookup_prefix(&self, prefix_values: &[&[u8]]) -> Vec<&[u8]> {
        let prefix = Self::build_key(prefix_values);
        let mut results = Vec::new();
        for (composite_key, primary_keys) in self.tree.range(prefix.clone()..) {
            if !composite_key.starts_with(&prefix) {
                break;
            }
            for pk in primary_keys {
                results.push(pk.as_slice());
            }
        }
        results
    }

    /// Total number of index entries.
    pub fn entry_count(&self) -> usize {