atomr_persistence_aws/
keys.rs

1//! Helpers for the single-table sort key layout.
2
3pub const EVENT_PREFIX: &str = "E#";
4pub const SNAPSHOT_PREFIX: &str = "S#";
5
6const SK_WIDTH: usize = 20;
7
8pub fn event_sk(sequence_nr: u64) -> String {
9    format!("{EVENT_PREFIX}{seq:0width$}", seq = sequence_nr, width = SK_WIDTH)
10}
11
12pub fn snapshot_sk(sequence_nr: u64) -> String {
13    format!("{SNAPSHOT_PREFIX}{seq:0width$}", seq = sequence_nr, width = SK_WIDTH)
14}
15
16pub fn parse_sequence(sk: &str) -> Option<u64> {
17    let stripped = sk.strip_prefix(EVENT_PREFIX).or_else(|| sk.strip_prefix(SNAPSHOT_PREFIX))?;
18    stripped.parse().ok()
19}
20
21#[cfg(test)]
22mod tests {
23    use super::*;
24
25    #[test]
26    fn lex_order_matches_numeric() {
27        let low = event_sk(1);
28        let high = event_sk(1_000_000);
29        assert!(low < high, "{low} vs {high}");
30    }
31
32    #[test]
33    fn parse_round_trip() {
34        assert_eq!(parse_sequence(&event_sk(42)), Some(42));
35        assert_eq!(parse_sequence(&snapshot_sk(7)), Some(7));
36        assert_eq!(parse_sequence("bogus"), None);
37    }
38}
atomr_persistence_aws/keys.rs

atomr_persistence_aws/
keys.rs
