fn update_or_advance_shard()

in below/store/src/cursor.rs [262:297]

• 30 lines of code
• 6 McCabe index (conditional complexity)

    fn update_or_advance_shard(&mut self, direction: Direction) -> Result<bool> {
        let entries = get_index_files(&self.path)?;

        let entries_iter: Box<dyn Iterator<Item = &String>> = match direction {
            Direction::Forward => Box::new(entries.iter()),
            Direction::Reverse => Box::new(entries.iter().rev()),
        };
        for entry in entries_iter {
            let v: Vec<&str> = entry.split('_').collect();
            if v.len() != 2 {
                warn!(self.logger, "Invalid index file name: {}", entry);
                continue;
            }

            let entry_shard = match v[1].parse::<u64>() {
                Ok(val) => val,
                _ => {
                    warn!(self.logger, "Cannot parse index shard: {}", entry);
                    continue;
                }
            };

            if let Some(shard) = self.shard.as_ref() {
                if entry_shard.cmp(shard) == direction.get_skip_order() {
                    continue;
                }
            }

            // Try to refresh the current shard (any new entries appended?) or
            // move to a different shard.
            if self.update_shard(entry_shard)? {
                return Ok(true);
            }
        }
        Ok(false)
    }