xxai_postgres_types/
pg_lsn.rs

1//! Log Sequence Number (LSN) type for PostgreSQL Write-Ahead Log
2//! (WAL), also known as the transaction log.
3
4use bytes::BytesMut;
5use postgres_protocol::types;
6use std::error::Error;
7use std::fmt;
8use std::str::FromStr;
9
10use crate::{FromSql, IsNull, ToSql, Type};
11
12/// Postgres `PG_LSN` type.
13#[derive(Clone, Copy, Eq, Ord, PartialEq, PartialOrd)]
14pub struct PgLsn(u64);
15
16/// Error parsing LSN.
17#[derive(Debug)]
18pub struct ParseLsnError(());
19
20impl From<u64> for PgLsn {
21    fn from(lsn_u64: u64) -> Self {
22        PgLsn(lsn_u64)
23    }
24}
25
26impl From<PgLsn> for u64 {
27    fn from(lsn: PgLsn) -> u64 {
28        lsn.0
29    }
30}
31
32impl FromStr for PgLsn {
33    type Err = ParseLsnError;
34
35    fn from_str(lsn_str: &str) -> Result<Self, Self::Err> {
36        let split: Vec<&str> = lsn_str.split('/').collect();
37        if split.len() == 2 {
38            let (hi, lo) = (
39                u64::from_str_radix(split[0], 16).map_err(|_| ParseLsnError(()))?,
40                u64::from_str_radix(split[1], 16).map_err(|_| ParseLsnError(()))?,
41            );
42            Ok(PgLsn((hi << 32) | lo))
43        } else {
44            Err(ParseLsnError(()))
45        }
46    }
47}
48
49impl fmt::Display for PgLsn {
50    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
51        write!(f, "{:X}/{:X}", self.0 >> 32, self.0 & 0x00000000ffffffff)
52    }
53}
54
55impl fmt::Debug for PgLsn {
56    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
57        f.write_fmt(format_args!("{}", self))
58    }
59}
60
61impl<'a> FromSql<'a> for PgLsn {
62    fn from_sql(_: &Type, raw: &'a [u8]) -> Result<Self, Box<dyn Error + Sync + Send>> {
63        let v = types::lsn_from_sql(raw)?;
64        Ok(v.into())
65    }
66
67    accepts!(PG_LSN);
68}
69
70impl ToSql for PgLsn {
71    fn to_sql(&self, _: &Type, out: &mut BytesMut) -> Result<IsNull, Box<dyn Error + Sync + Send>> {
72        types::lsn_to_sql((*self).into(), out);
73        Ok(IsNull::No)
74    }
75
76    accepts!(PG_LSN);
77
78    to_sql_checked!();
79}
xxai_postgres_types/pg_lsn.rs

xxai_postgres_types/
pg_lsn.rs
