1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
// This is a part of Chrono.
// See README.md and LICENSE.txt for details.

//! The UTC (Coordinated Universal Time) time zone.

use core::fmt;
#[cfg(all(
    feature = "now",
    not(all(
        target_arch = "wasm32",
        feature = "wasmbind",
        not(any(target_os = "emscripten", target_os = "wasi"))
    ))
))]
use std::time::{SystemTime, UNIX_EPOCH};

#[cfg(any(feature = "rkyv", feature = "rkyv-16", feature = "rkyv-32", feature = "rkyv-64"))]
use rkyv::{Archive, Deserialize, Serialize};

use super::{FixedOffset, MappedLocalTime, Offset, TimeZone};
use crate::naive::{NaiveDate, NaiveDateTime};
#[cfg(feature = "now")]
#[allow(deprecated)]
use crate::{Date, DateTime};

/// The UTC time zone. This is the most efficient time zone when you don't need the local time.
/// It is also used as an offset (which is also a dummy type).
///
/// Using the [`TimeZone`](./trait.TimeZone.html) methods
/// on the UTC struct is the preferred way to construct `DateTime<Utc>`
/// instances.
///
/// # Example
///
/// ```
/// use chrono::{DateTime, TimeZone, Utc};
///
/// let dt = DateTime::from_timestamp(61, 0).unwrap();
///
/// assert_eq!(Utc.timestamp_opt(61, 0).unwrap(), dt);
/// assert_eq!(Utc.with_ymd_and_hms(1970, 1, 1, 0, 1, 1).unwrap(), dt);
/// ```
#[derive(Copy, Clone, PartialEq, Eq, Hash)]
#[cfg_attr(
    any(feature = "rkyv", feature = "rkyv-16", feature = "rkyv-32", feature = "rkyv-64"),
    derive(Archive, Deserialize, Serialize),
    archive(compare(PartialEq)),
    archive_attr(derive(Clone, Copy, PartialEq, Eq, Debug, Hash))
)]
#[cfg_attr(feature = "rkyv-validation", archive(check_bytes))]
#[cfg_attr(all(feature = "arbitrary", feature = "std"), derive(arbitrary::Arbitrary))]
pub struct Utc;

#[cfg(feature = "now")]
impl Utc {
    /// Returns a `Date` which corresponds to the current date.
    #[deprecated(
        since = "0.4.23",
        note = "use `Utc::now()` instead, potentially with `.date_naive()`"
    )]
    #[allow(deprecated)]
    #[must_use]
    pub fn today() -> Date<Utc> {
        Utc::now().date()
    }

    /// Returns a `DateTime<Utc>` which corresponds to the current date and time in UTC.
    ///
    /// See also the similar [`Local::now()`] which returns `DateTime<Local>`, i.e. the local date
    /// and time including offset from UTC.
    ///
    /// [`Local::now()`]: crate::Local::now
    ///
    /// # Example
    ///
    /// ```
    /// # #![allow(unused_variables)]
    /// # use chrono::{FixedOffset, Utc};
    /// // Current time in UTC
    /// let now_utc = Utc::now();
    ///
    /// // Current date in UTC
    /// let today_utc = now_utc.date_naive();
    ///
    /// // Current time in some timezone (let's use +05:00)
    /// let offset = FixedOffset::east_opt(5 * 60 * 60).unwrap();
    /// let now_with_offset = Utc::now().with_timezone(&offset);
    /// ```
    #[cfg(not(all(
        target_arch = "wasm32",
        feature = "wasmbind",
        not(any(target_os = "emscripten", target_os = "wasi"))
    )))]
    #[must_use]
    pub fn now() -> DateTime<Utc> {
        let now =
            SystemTime::now().duration_since(UNIX_EPOCH).expect("system time before Unix epoch");
        DateTime::from_timestamp(now.as_secs() as i64, now.subsec_nanos()).unwrap()
    }

    /// Returns a `DateTime` which corresponds to the current date and time.
    #[cfg(all(
        target_arch = "wasm32",
        feature = "wasmbind",
        not(any(target_os = "emscripten", target_os = "wasi"))
    ))]
    #[must_use]
    pub fn now() -> DateTime<Utc> {
        let now = js_sys::Date::new_0();
        DateTime::<Utc>::from(now)
    }
}

impl TimeZone for Utc {
    type Offset = Utc;

    fn from_offset(_state: &Utc) -> Utc {
        Utc
    }

    fn offset_from_local_date(&self, _local: &NaiveDate) -> MappedLocalTime<Utc> {
        MappedLocalTime::Single(Utc)
    }
    fn offset_from_local_datetime(&self, _local: &NaiveDateTime) -> MappedLocalTime<Utc> {
        MappedLocalTime::Single(Utc)
    }

    fn offset_from_utc_date(&self, _utc: &NaiveDate) -> Utc {
        Utc
    }
    fn offset_from_utc_datetime(&self, _utc: &NaiveDateTime) -> Utc {
        Utc
    }
}

impl Offset for Utc {
    fn fix(&self) -> FixedOffset {
        FixedOffset::east_opt(0).unwrap()
    }
}

impl fmt::Debug for Utc {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "Z")
    }
}

impl fmt::Display for Utc {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "UTC")
    }
}