fn timestamp_parser()

in native/spark-expr/src/conversion_funcs/cast.rs [1773:1846]

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

fn timestamp_parser<T: TimeZone>(
    value: &str,
    eval_mode: EvalMode,
    tz: &T,
) -> SparkResult<Option<i64>> {
    let value = value.trim();
    if value.is_empty() {
        return Ok(None);
    }
    // Define regex patterns and corresponding parsing functions
    let patterns = &[
        (
            Regex::new(r"^\d{4,5}$").unwrap(),
            parse_str_to_year_timestamp as fn(&str, &T) -> SparkResult<Option<i64>>,
        ),
        (
            Regex::new(r"^\d{4,5}-\d{2}$").unwrap(),
            parse_str_to_month_timestamp,
        ),
        (
            Regex::new(r"^\d{4,5}-\d{2}-\d{2}$").unwrap(),
            parse_str_to_day_timestamp,
        ),
        (
            Regex::new(r"^\d{4,5}-\d{2}-\d{2}T\d{1,2}$").unwrap(),
            parse_str_to_hour_timestamp,
        ),
        (
            Regex::new(r"^\d{4,5}-\d{2}-\d{2}T\d{2}:\d{2}$").unwrap(),
            parse_str_to_minute_timestamp,
        ),
        (
            Regex::new(r"^\d{4,5}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}$").unwrap(),
            parse_str_to_second_timestamp,
        ),
        (
            Regex::new(r"^\d{4,5}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}\.\d{1,6}$").unwrap(),
            parse_str_to_microsecond_timestamp,
        ),
        (
            Regex::new(r"^T\d{1,2}$").unwrap(),
            parse_str_to_time_only_timestamp,
        ),
    ];

    let mut timestamp = None;

    // Iterate through patterns and try matching
    for (pattern, parse_func) in patterns {
        if pattern.is_match(value) {
            timestamp = parse_func(value, tz)?;
            break;
        }
    }

    if timestamp.is_none() {
        return if eval_mode == EvalMode::Ansi {
            Err(SparkError::CastInvalidValue {
                value: value.to_string(),
                from_type: "STRING".to_string(),
                to_type: "TIMESTAMP".to_string(),
            })
        } else {
            Ok(None)
        };
    }

    match timestamp {
        Some(ts) => Ok(Some(ts)),
        None => Err(SparkError::Internal(
            "Failed to parse timestamp".to_string(),
        )),
    }
}