library/std/src/sys/hermit/time.rs

   1 #![allow(dead_code)]
   2
   3 use crate::cmp::Ordering;
   4 use crate::convert::TryInto;
   5 use crate::sys::hermit::abi;
   6 use crate::sys::hermit::abi::timespec;
   7 use crate::sys::hermit::abi::{CLOCK_MONOTONIC, CLOCK_REALTIME, NSEC_PER_SEC};
   8 use crate::time::Duration;
   9 use core::hash::{Hash, Hasher};
  10
  11 #[derive(Copy, Clone, Debug)]
  12 struct Timespec {
  13     t: timespec,
  14 }
  15
  16 impl Timespec {
  17     const fn zero() -> Timespec {
  18         Timespec { t: timespec { tv_sec: 0, tv_nsec: 0 } }
  19     }
  20
  21     fn sub_timespec(&self, other: &Timespec) -> Result<Duration, Duration> {
  22         if self >= other {
  23             Ok(if self.t.tv_nsec >= other.t.tv_nsec {
  24                 Duration::new(
  25                     (self.t.tv_sec - other.t.tv_sec) as u64,
  26                     (self.t.tv_nsec - other.t.tv_nsec) as u32,
  27                 )
  28             } else {
  29                 Duration::new(
  30                     (self.t.tv_sec - 1 - other.t.tv_sec) as u64,
  31                     self.t.tv_nsec as u32 + (NSEC_PER_SEC as u32) - other.t.tv_nsec as u32,
  32                 )
  33             })
  34         } else {
  35             match other.sub_timespec(self) {
  36                 Ok(d) => Err(d),
  37                 Err(d) => Ok(d),
  38             }
  39         }
  40     }
  41
  42     fn checked_add_duration(&self, other: &Duration) -> Option<Timespec> {
  43         let mut secs = other
  44             .as_secs()
  45             .try_into() // <- target type would be `libc::time_t`
  46             .ok()
  47             .and_then(|secs| self.t.tv_sec.checked_add(secs))?;
  48
  49         // Nano calculations can't overflow because nanos are <1B which fit
  50         // in a u32.
  51         let mut nsec = other.subsec_nanos() + self.t.tv_nsec as u32;
  52         if nsec >= NSEC_PER_SEC as u32 {
  53             nsec -= NSEC_PER_SEC as u32;
  54             secs = secs.checked_add(1)?;
  55         }
  56         Some(Timespec { t: timespec { tv_sec: secs, tv_nsec: nsec as _ } })
  57     }
  58
  59     fn checked_sub_duration(&self, other: &Duration) -> Option<Timespec> {
  60         let mut secs = other
  61             .as_secs()
  62             .try_into() // <- target type would be `libc::time_t`
  63             .ok()
  64             .and_then(|secs| self.t.tv_sec.checked_sub(secs))?;
  65
  66         // Similar to above, nanos can't overflow.
  67         let mut nsec = self.t.tv_nsec as i32 - other.subsec_nanos() as i32;
  68         if nsec < 0 {
  69             nsec += NSEC_PER_SEC as i32;
  70             secs = secs.checked_sub(1)?;
  71         }
  72         Some(Timespec { t: timespec { tv_sec: secs, tv_nsec: nsec as _ } })
  73     }
  74 }
  75
  76 impl PartialEq for Timespec {
  77     fn eq(&self, other: &Timespec) -> bool {
  78         self.t.tv_sec == other.t.tv_sec && self.t.tv_nsec == other.t.tv_nsec
  79     }
  80 }
  81
  82 impl Eq for Timespec {}
  83
  84 impl PartialOrd for Timespec {
  85     fn partial_cmp(&self, other: &Timespec) -> Option<Ordering> {
  86         Some(self.cmp(other))
  87     }
  88 }
  89
  90 impl Ord for Timespec {
  91     fn cmp(&self, other: &Timespec) -> Ordering {
  92         let me = (self.t.tv_sec, self.t.tv_nsec);
  93         let other = (other.t.tv_sec, other.t.tv_nsec);
  94         me.cmp(&other)
  95     }
  96 }
  97
  98 impl Hash for Timespec {
  99     fn hash<H: Hasher>(&self, state: &mut H) {
 100         self.t.tv_sec.hash(state);
 101         self.t.tv_nsec.hash(state);
 102     }
 103 }
 104
 105 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
 106 pub struct Instant {
 107     t: Timespec,
 108 }
 109
 110 impl Instant {
 111     pub fn now() -> Instant {
 112         let mut time: Timespec = Timespec::zero();
 113         let _ = unsafe { abi::clock_gettime(CLOCK_MONOTONIC, &mut time.t as *mut timespec) };
 114
 115         Instant { t: time }
 116     }
 117
 118     pub const fn zero() -> Instant {
 119         Instant { t: Timespec::zero() }
 120     }
 121
 122     pub fn actually_monotonic() -> bool {
 123         true
 124     }
 125
 126     pub fn checked_sub_instant(&self, other: &Instant) -> Option<Duration> {
 127         self.t.sub_timespec(&other.t).ok()
 128     }
 129
 130     pub fn checked_add_duration(&self, other: &Duration) -> Option<Instant> {
 131         Some(Instant { t: self.t.checked_add_duration(other)? })
 132     }
 133
 134     pub fn checked_sub_duration(&self, other: &Duration) -> Option<Instant> {
 135         Some(Instant { t: self.t.checked_sub_duration(other)? })
 136     }
 137 }
 138
 139 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
 140 pub struct SystemTime {
 141     t: Timespec,
 142 }
 143
 144 pub const UNIX_EPOCH: SystemTime = SystemTime { t: Timespec::zero() };
 145
 146 impl SystemTime {
 147     pub fn now() -> SystemTime {
 148         let mut time: Timespec = Timespec::zero();
 149         let _ = unsafe { abi::clock_gettime(CLOCK_REALTIME, &mut time.t as *mut timespec) };
 150
 151         SystemTime { t: time }
 152     }
 153
 154     pub fn sub_time(&self, other: &SystemTime) -> Result<Duration, Duration> {
 155         self.t.sub_timespec(&other.t)
 156     }
 157
 158     pub fn checked_add_duration(&self, other: &Duration) -> Option<SystemTime> {
 159         Some(SystemTime { t: self.t.checked_add_duration(other)? })
 160     }
 161
 162     pub fn checked_sub_duration(&self, other: &Duration) -> Option<SystemTime> {
 163         Some(SystemTime { t: self.t.checked_sub_duration(other)? })
 164     }
 165 }