cbor_core/
date_time.rs

1use std::time::{Duration, SystemTime};
2
3use crate::iso3339::Timestamp;
4use crate::{Error, Result, Value, tag};
5
6const LEAP_SECOND_DATES: [(u16, u8, u8); 27] = [
7    (1972, 6, 30),
8    (1972, 12, 31),
9    (1973, 12, 31),
10    (1974, 12, 31),
11    (1975, 12, 31),
12    (1976, 12, 31),
13    (1977, 12, 31),
14    (1978, 12, 31),
15    (1979, 12, 31),
16    (1981, 6, 30),
17    (1982, 6, 30),
18    (1983, 6, 30),
19    (1985, 6, 30),
20    (1987, 12, 31),
21    (1989, 12, 31),
22    (1990, 12, 31),
23    (1992, 6, 30),
24    (1993, 6, 30),
25    (1994, 6, 30),
26    (1995, 12, 31),
27    (1997, 6, 30),
28    (1998, 12, 31),
29    (2005, 12, 31),
30    (2008, 12, 31),
31    (2012, 6, 30),
32    (2015, 6, 30),
33    (2016, 12, 31),
34];
35
36/// Helper for validated date/time string construction.
37///
38/// Wraps an RFC 3339 (an ISO 8601 profile) UTC string suitable
39/// for CBOR tag 0. The string is validated on creation: the date
40/// must be within `0001-01-01T00:00:00Z` to `9999-12-31T23:59:59Z`,
41/// and follow RFC 3339 section 5.6 layout.
42///
43/// Whole-second timestamps omit the fractional part. Sub-second
44/// timestamps include only the necessary digits (1-9, no trailing
45/// zeros).
46///
47/// CBOR::Core references section 5.6 of RFC3339, which allows
48/// leap seconds (second == 60). So we accept leap seconds and
49/// validate, if the date is one of the currently known 27
50/// leap second dates.
51///
52/// However, trying to convert a date/time value containing a
53/// leap second to `SystemTime` will fail with `Err(InvalidEncoding)`.
54///
55/// Implements `TryFrom<SystemTime>` and `TryFrom<&str>`, so that
56/// [`Value::date_time`] can accept both through a single
57/// `TryInto<DateTime>` bound.
58#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
59pub struct DateTime(String);
60
61impl From<DateTime> for Value<'_> {
62    fn from(value: DateTime) -> Self {
63        Self::tag(tag::DATE_TIME, value.0)
64    }
65}
66
67/// Borrows the timestamp text rather than cloning it.
68///
69/// The resulting `Value::Tag` still requires a small allocation
70/// for the boxed tag content; only the timestamp string itself
71/// is borrowed.
72impl<'a> From<&'a DateTime> for Value<'a> {
73    fn from(value: &'a DateTime) -> Self {
74        Self::tag(tag::DATE_TIME, value.0.as_str())
75    }
76}
77
78impl TryFrom<SystemTime> for DateTime {
79    type Error = Error;
80
81    fn try_from(value: SystemTime) -> Result<Self> {
82        if let Ok(time) = value.duration_since(SystemTime::UNIX_EPOCH)
83            && time > Duration::from_secs(253402300799)
84        {
85            return Err(Error::InvalidValue);
86        }
87
88        let ts = Timestamp::try_new(value)?;
89        Ok(Self(ts.to_string()))
90    }
91}
92
93fn validate_date_time(s: &str) -> Result<()> {
94    let ts: Timestamp = s.parse()?;
95
96    if ts.year > 9999 {
97        return Err(Error::InvalidValue);
98    }
99
100    if ts.second == 60 {
101        if ts.hour != 23 || ts.minute != 59 {
102            return Err(Error::InvalidValue);
103        }
104
105        if !LEAP_SECOND_DATES.contains(&(ts.year, ts.month, ts.day)) {
106            return Err(Error::InvalidValue);
107        }
108    }
109
110    if ts.year < 9999 || ts.month < 12 || ts.day < 31 || ts.hour < 23 || ts.minute < 59 || ts.second < 59 {
111        Ok(())
112    } else if ts.second > 59 || (ts.nano_seconds > 0 && ts.offset == 0) || ts.offset < 0 {
113        Err(Error::InvalidValue)
114    } else {
115        Ok(())
116    }
117}
118
119impl TryFrom<&str> for DateTime {
120    type Error = Error;
121
122    fn try_from(value: &str) -> Result<Self> {
123        validate_date_time(value)?;
124        Ok(Self(value.to_string()))
125    }
126}
127
128impl TryFrom<String> for DateTime {
129    type Error = Error;
130
131    fn try_from(value: String) -> Result<Self> {
132        validate_date_time(&value)?;
133        Ok(Self(value))
134    }
135}
136
137impl TryFrom<&String> for DateTime {
138    type Error = Error;
139
140    fn try_from(value: &String) -> Result<Self> {
141        validate_date_time(value)?;
142        Ok(Self(value.clone()))
143    }
144}
145
146impl TryFrom<Box<str>> for DateTime {
147    type Error = Error;
148
149    fn try_from(value: Box<str>) -> Result<Self> {
150        validate_date_time(value.as_ref())?;
151        Ok(Self(value.to_string()))
152    }
153}
cbor_core/date_time.rs

cbor_core/
date_time.rs
