mz_repr/adt/
date.rs

1// Copyright Materialize, Inc. and contributors. All rights reserved.
2//
3// Use of this software is governed by the Business Source License
4// included in the LICENSE file.
5//
6// As of the Change Date specified in that file, in accordance with
7// the Business Source License, use of this software will be governed
8// by the Apache License, Version 2.0.
9
10//! A time Date abstract data type.
11
12use std::convert::TryFrom;
13use std::fmt;
14use std::ops::Sub;
15use std::sync::LazyLock;
16
17use anyhow::anyhow;
18use chrono::NaiveDate;
19use mz_proto::{RustType, TryFromProtoError};
20use serde::{Deserialize, Serialize};
21use thiserror::Error;
22
23include!(concat!(env!("OUT_DIR"), "/mz_repr.adt.date.rs"));
24
25#[derive(Debug, Error)]
26pub enum DateError {
27    #[error("data out of range")]
28    OutOfRange,
29}
30
31/// A Postgres-compatible Date. Additionally clamp valid dates for the range
32/// that chrono supports to allow for safe string operations. Infinite dates are
33/// not yet supported.
34#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Serialize, Hash, Deserialize)]
35pub struct Date {
36    /// Number of days from the postgres epoch (2000-01-01).
37    days: i32,
38}
39
40impl RustType<ProtoDate> for Date {
41    fn into_proto(&self) -> ProtoDate {
42        ProtoDate { days: self.days }
43    }
44
45    fn from_proto(proto: ProtoDate) -> Result<Self, TryFromProtoError> {
46        Ok(Date { days: proto.days })
47    }
48}
49
50impl std::str::FromStr for Date {
51    type Err = anyhow::Error;
52
53    fn from_str(s: &str) -> Result<Self, Self::Err> {
54        crate::strconv::parse_date(s).map_err(|e| anyhow!(e))
55    }
56}
57
58static PG_EPOCH: LazyLock<NaiveDate> =
59    LazyLock::new(|| NaiveDate::from_ymd_opt(2000, 1, 1).unwrap());
60
61impl Date {
62    pub const UNIX_EPOCH_TO_PG_EPOCH: i32 = 10957; // Number of days from 1970-01-01 to 2000-01-01.
63    const CE_EPOCH_TO_PG_EPOCH: i32 = 730120; // Number of days since 0001-01-01 to 2000-01-01.
64    pub const LOW_DAYS: i32 = -2451545; // 4714-11-24 BC
65
66    /// Largest date support by Materialize. Although Postgres can go up to
67    /// 5874897-12-31, chrono is limited to December 31, 262142, which we mirror
68    /// here so we can use chrono's formatting methods and have guaranteed safe
69    /// conversions.
70    pub const HIGH_DAYS: i32 = 95_015_279;
71
72    /// Constructs a new `Date` as the days since the postgres epoch
73    /// (2000-01-01).
74    pub fn from_pg_epoch(days: i32) -> Result<Date, DateError> {
75        if days < Self::LOW_DAYS || days > Self::HIGH_DAYS {
76            Err(DateError::OutOfRange)
77        } else {
78            Ok(Date { days })
79        }
80    }
81
82    /// Constructs a new `Date` as the days since the Unix epoch.
83    pub fn from_unix_epoch(unix_days: i32) -> Result<Date, DateError> {
84        let pg_days = unix_days.saturating_sub(Self::UNIX_EPOCH_TO_PG_EPOCH);
85        if pg_days == i32::MIN {
86            return Err(DateError::OutOfRange);
87        }
88        Self::from_pg_epoch(pg_days)
89    }
90
91    /// Returns the number of days since the postgres epoch.
92    pub fn pg_epoch_days(&self) -> i32 {
93        self.days
94    }
95
96    /// Returns whether this is the infinity or -infinity date.
97    ///
98    /// Currently we do not support these, so this function is a light
99    /// protection against if they are added for functions that will produce
100    /// incorrect results for these values.
101    pub fn is_finite(&self) -> bool {
102        self.days != i32::MAX && self.days != i32::MIN
103    }
104
105    /// Returns the number of days since the Unix epoch.
106    pub fn unix_epoch_days(&self) -> i32 {
107        assert!(self.is_finite());
108        // Guaranteed to be safe because we clamp the high date by less than the
109        // result of this.
110        self.days + Self::UNIX_EPOCH_TO_PG_EPOCH
111    }
112
113    /// Returns this date with `days` added to it.
114    pub fn checked_add(self, days: i32) -> Result<Date, DateError> {
115        let days = if let Some(days) = self.days.checked_add(days) {
116            days
117        } else {
118            return Err(DateError::OutOfRange);
119        };
120        Self::from_pg_epoch(days)
121    }
122}
123
124impl Sub for Date {
125    type Output = i32;
126
127    fn sub(self, rhs: Self) -> Self::Output {
128        assert!(self.is_finite());
129        self.days - rhs.days
130    }
131}
132
133impl From<Date> for NaiveDate {
134    fn from(date: Date) -> Self {
135        Self::from(&date)
136    }
137}
138
139impl From<&Date> for NaiveDate {
140    fn from(date: &Date) -> Self {
141        let days = date
142            .pg_epoch_days()
143            .checked_add(Date::CE_EPOCH_TO_PG_EPOCH)
144            .expect("out of range date are prevented");
145        NaiveDate::from_num_days_from_ce_opt(days).unwrap()
146    }
147}
148
149impl TryFrom<NaiveDate> for Date {
150    type Error = DateError;
151
152    fn try_from(value: NaiveDate) -> Result<Self, Self::Error> {
153        let d = value.signed_duration_since(*PG_EPOCH);
154        let days: i32 = d.num_days().try_into().map_err(|_| DateError::OutOfRange)?;
155        Self::from_pg_epoch(days)
156    }
157}
158
159/// Format an Date in a human form
160impl fmt::Display for Date {
161    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
162        let d: NaiveDate = (*self).into();
163        d.format("%Y-%m-%d").fmt(f)
164    }
165}
166
167#[cfg(test)]
168mod test {
169    use super::*;
170
171    #[mz_ore::test]
172    fn test_date() {
173        let pgepoch = Date::from_pg_epoch(0).unwrap();
174        let unixepoch = Date::from_unix_epoch(0).unwrap();
175        assert_eq!(pgepoch.pg_epoch_days(), 0);
176        assert_eq!(pgepoch.unix_epoch_days(), 10957);
177        assert_eq!(unixepoch.pg_epoch_days(), -10957);
178        assert_eq!(unixepoch.unix_epoch_days(), 0);
179        assert_eq!(
180            NaiveDate::from(pgepoch),
181            NaiveDate::from_ymd_opt(2000, 1, 1).unwrap()
182        );
183        assert_eq!(
184            pgepoch,
185            Date::try_from(NaiveDate::from_ymd_opt(2000, 1, 1).unwrap()).unwrap()
186        );
187        assert_eq!(
188            unixepoch,
189            Date::try_from(NaiveDate::from_ymd_opt(1970, 1, 1).unwrap()).unwrap()
190        );
191        assert_eq!(
192            unixepoch,
193            Date::try_from(NaiveDate::from_ymd_opt(1970, 1, 1).unwrap()).unwrap()
194        );
195        assert!(pgepoch > unixepoch);
196    }
197}
mz_repr/adt/date.rs

mz_repr/adt/
date.rs
