std/sys/time/
unix.rs

1use crate::sys::AsInner;
2use crate::sys::pal::time::Timespec;
3use crate::time::Duration;
4use crate::{fmt, io};
5
6pub const UNIX_EPOCH: SystemTime = SystemTime { t: Timespec::zero() };
7
8#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
9pub struct SystemTime {
10    pub(crate) t: Timespec,
11}
12
13impl SystemTime {
14    pub const MAX: SystemTime = SystemTime { t: Timespec::MAX };
15
16    pub const MIN: SystemTime = SystemTime { t: Timespec::MIN };
17
18    #[cfg_attr(any(target_os = "horizon", target_os = "hurd", target_os = "teeos"), expect(unused))]
19    pub fn new(tv_sec: i64, tv_nsec: i64) -> Result<SystemTime, io::Error> {
20        Ok(SystemTime { t: Timespec::new(tv_sec, tv_nsec)? })
21    }
22
23    pub fn now() -> SystemTime {
24        SystemTime { t: Timespec::now(libc::CLOCK_REALTIME) }
25    }
26
27    pub fn sub_time(&self, other: &SystemTime) -> Result<Duration, Duration> {
28        self.t.sub_timespec(&other.t)
29    }
30
31    pub fn checked_add_duration(&self, other: &Duration) -> Option<SystemTime> {
32        Some(SystemTime { t: self.t.checked_add_duration(other)? })
33    }
34
35    pub fn checked_sub_duration(&self, other: &Duration) -> Option<SystemTime> {
36        Some(SystemTime { t: self.t.checked_sub_duration(other)? })
37    }
38}
39
40impl fmt::Debug for SystemTime {
41    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
42        f.debug_struct("SystemTime")
43            .field("tv_sec", &self.t.tv_sec)
44            .field("tv_nsec", &self.t.tv_nsec)
45            .finish()
46    }
47}
48
49#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
50pub struct Instant {
51    t: Timespec,
52}
53
54impl Instant {
55    // CLOCK_UPTIME_RAW   clock that increments monotonically, in the same man-
56    //                    ner as CLOCK_MONOTONIC_RAW, but that does not incre-
57    //                    ment while the system is asleep.  The returned value
58    //                    is identical to the result of mach_absolute_time()
59    //                    after the appropriate mach_timebase conversion is
60    //                    applied.
61    //
62    // We use `CLOCK_UPTIME_RAW` instead of `CLOCK_MONOTONIC` since
63    // `CLOCK_UPTIME_RAW` is based on `mach_absolute_time`, which is the
64    // clock that all timeouts and deadlines are measured against inside
65    // the kernel.
66    #[cfg(target_vendor = "apple")]
67    pub(crate) const CLOCK_ID: libc::clockid_t = libc::CLOCK_UPTIME_RAW;
68
69    #[cfg(not(target_vendor = "apple"))]
70    pub(crate) const CLOCK_ID: libc::clockid_t = libc::CLOCK_MONOTONIC;
71
72    pub fn now() -> Instant {
73        // https://pubs.opengroup.org/onlinepubs/9799919799/functions/clock_getres.html
74        Instant { t: Timespec::now(Self::CLOCK_ID) }
75    }
76
77    pub fn checked_sub_instant(&self, other: &Instant) -> Option<Duration> {
78        self.t.sub_timespec(&other.t).ok()
79    }
80
81    pub fn checked_add_duration(&self, other: &Duration) -> Option<Instant> {
82        Some(Instant { t: self.t.checked_add_duration(other)? })
83    }
84
85    pub fn checked_sub_duration(&self, other: &Duration) -> Option<Instant> {
86        Some(Instant { t: self.t.checked_sub_duration(other)? })
87    }
88
89    #[cfg_attr(
90        not(target_os = "linux"),
91        allow(unused, reason = "needed by the `sleep_until` on some unix platforms")
92    )]
93    pub(crate) fn into_timespec(self) -> Timespec {
94        self.t
95    }
96
97    /// Returns `self` converted into units of `mach_absolute_time`, or `None`
98    /// if `self` is before the system boot time. If the conversion cannot be
99    /// performed precisely, this ceils the result up to the nearest
100    /// representable value.
101    #[cfg(target_vendor = "apple")]
102    pub fn into_mach_absolute_time_ceil(self) -> Option<u128> {
103        #[repr(C)]
104        struct mach_timebase_info {
105            numer: u32,
106            denom: u32,
107        }
108
109        unsafe extern "C" {
110            unsafe fn mach_timebase_info(info: *mut mach_timebase_info) -> libc::kern_return_t;
111        }
112
113        let secs = u64::try_from(self.t.tv_sec).ok()?;
114
115        let mut timebase = mach_timebase_info { numer: 0, denom: 0 };
116        assert_eq!(unsafe { mach_timebase_info(&mut timebase) }, libc::KERN_SUCCESS);
117
118        // Since `tv_sec` is 64-bit and `tv_nsec` is smaller than 1 billion,
119        // this cannot overflow. The resulting number needs at most 94 bits.
120        let nanos = 1_000_000_000 * u128::from(secs) + u128::from(self.t.tv_nsec.as_inner());
121        // This multiplication cannot overflow since multiplying a 94-bit
122        // number by a 32-bit number yields a number that needs at most
123        // 126 bits.
124        Some((nanos * u128::from(timebase.denom)).div_ceil(u128::from(timebase.numer)))
125    }
126}
127
128impl AsInner<Timespec> for Instant {
129    fn as_inner(&self) -> &Timespec {
130        &self.t
131    }
132}
133
134impl fmt::Debug for Instant {
135    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
136        f.debug_struct("Instant")
137            .field("tv_sec", &self.t.tv_sec)
138            .field("tv_nsec", &self.t.tv_nsec)
139            .finish()
140    }
141}
std/sys/time/unix.rs

std/sys/time/
unix.rs
