fn read_kv_diff_line()

in below/procfs/src/lib.rs [1012:1069]

• 48 lines of code
• 9 McCabe index (conditional complexity)

    fn read_kv_diff_line(&self, stats_filename: &str) -> Result<BTreeMap<String, u64>> {
        let cur_path = self
            .proc_net_dir
            .recover_path()
            .unwrap_or_else(|_| NET_PROCFS.into())
            .join(stats_filename);
        let stats_file = self
            .proc_net_dir
            .open_file(stats_filename)
            .map_err(|e| Error::IoError(cur_path.clone(), e))?;

        let buf_reader = BufReader::new(stats_file);
        let content: Vec<String> = buf_reader
            .lines()
            .filter_map(|line| match line {
                Ok(l) => Some(l),
                _ => None,
            })
            .collect();

        let mut res = BTreeMap::new();
        for topic in content.chunks(2) {
            let fields: Vec<&str> = topic[0].split(':').collect();
            let vals: Vec<&str> = topic[1].split(':').collect();

            if fields.len() != 2 || vals.len() != 2 || fields.len() != vals.len() {
                return Err(Error::InvalidFileFormat(cur_path));
            }

            let key_header = fields[0];
            let keys: Vec<&str> = fields[1].split_whitespace().collect();
            let vals: Vec<&str> = vals[1].split_whitespace().collect();

            if keys.is_empty() && keys.len() != vals.len() {
                return Err(Error::InvalidFileFormat(cur_path));
            }

            for (&k, &v) in keys.iter().zip(vals.iter()) {
                // There's case that stats like max_conn may have -1 value that represent no max. It's
                // safe to skip such value and keep the result as None.
                if v.starts_with('-') {
                    continue;
                }

                res.insert(
                    format!("{}_{}", key_header, &k),
                    v.parse::<u64>().map_err(|_| Error::ParseError {
                        line: k.into(),
                        item: v.into(),
                        type_name: "u64".into(),
                        path: cur_path.clone(),
                    })?,
                );
            }
        }

        Ok(res)
    }