1 files changed, 352 insertions, 0 deletions
diff --git a/library/std/src/sys/unix/time.rs b/library/std/src/sys/unix/time.rs
new file mode 100644
index 00000000000..6707f790cab
--- /dev/null
+++ b/library/std/src/sys/unix/time.rs
@@ -0,0 +1,352 @@
+use crate::cmp::Ordering;
+use crate::time::Duration;
+
+use core::hash::{Hash, Hasher};
+
+pub use self::inner::{Instant, SystemTime, UNIX_EPOCH};
+use crate::convert::TryInto;
+
+const NSEC_PER_SEC: u64 = 1_000_000_000;
+
+#[derive(Copy, Clone)]
+struct Timespec {
+    t: libc::timespec,
+}
+
+impl Timespec {
+    const fn zero() -> Timespec {
+        Timespec { t: libc::timespec { tv_sec: 0, tv_nsec: 0 } }
+    }
+
+    fn sub_timespec(&self, other: &Timespec) -> Result<Duration, Duration> {
+        if self >= other {
+            Ok(if self.t.tv_nsec >= other.t.tv_nsec {
+                Duration::new(
+                    (self.t.tv_sec - other.t.tv_sec) as u64,
+                    (self.t.tv_nsec - other.t.tv_nsec) as u32,
+                )
+            } else {
+                Duration::new(
+                    (self.t.tv_sec - 1 - other.t.tv_sec) as u64,
+                    self.t.tv_nsec as u32 + (NSEC_PER_SEC as u32) - other.t.tv_nsec as u32,
+                )
+            })
+        } else {
+            match other.sub_timespec(self) {
+                Ok(d) => Err(d),
+                Err(d) => Ok(d),
+            }
+        }
+    }
+
+    fn checked_add_duration(&self, other: &Duration) -> Option<Timespec> {
+        let mut secs = other
+            .as_secs()
+            .try_into() // <- target type would be `libc::time_t`
+            .ok()
+            .and_then(|secs| self.t.tv_sec.checked_add(secs))?;
+
+        // Nano calculations can't overflow because nanos are <1B which fit
+        // in a u32.
+        let mut nsec = other.subsec_nanos() + self.t.tv_nsec as u32;
+        if nsec >= NSEC_PER_SEC as u32 {
+            nsec -= NSEC_PER_SEC as u32;
+            secs = secs.checked_add(1)?;
+        }
+        Some(Timespec { t: libc::timespec { tv_sec: secs, tv_nsec: nsec as _ } })
+    }
+
+    fn checked_sub_duration(&self, other: &Duration) -> Option<Timespec> {
+        let mut secs = other
+            .as_secs()
+            .try_into() // <- target type would be `libc::time_t`
+            .ok()
+            .and_then(|secs| self.t.tv_sec.checked_sub(secs))?;
+
+        // Similar to above, nanos can't overflow.
+        let mut nsec = self.t.tv_nsec as i32 - other.subsec_nanos() as i32;
+        if nsec < 0 {
+            nsec += NSEC_PER_SEC as i32;
+            secs = secs.checked_sub(1)?;
+        }
+        Some(Timespec { t: libc::timespec { tv_sec: secs, tv_nsec: nsec as _ } })
+    }
+}
+
+impl PartialEq for Timespec {
+    fn eq(&self, other: &Timespec) -> bool {
+        self.t.tv_sec == other.t.tv_sec && self.t.tv_nsec == other.t.tv_nsec
+    }
+}
+
+impl Eq for Timespec {}
+
+impl PartialOrd for Timespec {
+    fn partial_cmp(&self, other: &Timespec) -> Option<Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
+impl Ord for Timespec {
+    fn cmp(&self, other: &Timespec) -> Ordering {
+        let me = (self.t.tv_sec, self.t.tv_nsec);
+        let other = (other.t.tv_sec, other.t.tv_nsec);
+        me.cmp(&other)
+    }
+}
+
+impl Hash for Timespec {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        self.t.tv_sec.hash(state);
+        self.t.tv_nsec.hash(state);
+    }
+}
+
+#[cfg(any(target_os = "macos", target_os = "ios"))]
+mod inner {
+    use crate::fmt;
+    use crate::mem;
+    use crate::sync::atomic::{AtomicUsize, Ordering::SeqCst};
+    use crate::sys::cvt;
+    use crate::sys_common::mul_div_u64;
+    use crate::time::Duration;
+
+    use super::Timespec;
+    use super::NSEC_PER_SEC;
+
+    #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
+    pub struct Instant {
+        t: u64,
+    }
+
+    #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+    pub struct SystemTime {
+        t: Timespec,
+    }
+
+    pub const UNIX_EPOCH: SystemTime = SystemTime { t: Timespec::zero() };
+
+    #[repr(C)]
+    #[derive(Copy, Clone)]
+    struct mach_timebase_info {
+        numer: u32,
+        denom: u32,
+    }
+    type mach_timebase_info_t = *mut mach_timebase_info;
+    type kern_return_t = libc::c_int;
+
+    impl Instant {
+        pub fn now() -> Instant {
+            extern "C" {
+                fn mach_absolute_time() -> u64;
+            }
+            Instant { t: unsafe { mach_absolute_time() } }
+        }
+
+        pub const fn zero() -> Instant {
+            Instant { t: 0 }
+        }
+
+        pub fn actually_monotonic() -> bool {
+            true
+        }
+
+        pub fn checked_sub_instant(&self, other: &Instant) -> Option<Duration> {
+            let diff = self.t.checked_sub(other.t)?;
+            let info = info();
+            let nanos = mul_div_u64(diff, info.numer as u64, info.denom as u64);
+            Some(Duration::new(nanos / NSEC_PER_SEC, (nanos % NSEC_PER_SEC) as u32))
+        }
+
+        pub fn checked_add_duration(&self, other: &Duration) -> Option<Instant> {
+            Some(Instant { t: self.t.checked_add(checked_dur2intervals(other)?)? })
+        }
+
+        pub fn checked_sub_duration(&self, other: &Duration) -> Option<Instant> {
+            Some(Instant { t: self.t.checked_sub(checked_dur2intervals(other)?)? })
+        }
+    }
+
+    impl SystemTime {
+        pub fn now() -> SystemTime {
+            use crate::ptr;
+
+            let mut s = libc::timeval { tv_sec: 0, tv_usec: 0 };
+            cvt(unsafe { libc::gettimeofday(&mut s, ptr::null_mut()) }).unwrap();
+            return SystemTime::from(s);
+        }
+
+        pub fn sub_time(&self, other: &SystemTime) -> Result<Duration, Duration> {
+            self.t.sub_timespec(&other.t)
+        }
+
+        pub fn checked_add_duration(&self, other: &Duration) -> Option<SystemTime> {
+            Some(SystemTime { t: self.t.checked_add_duration(other)? })
+        }
+
+        pub fn checked_sub_duration(&self, other: &Duration) -> Option<SystemTime> {
+            Some(SystemTime { t: self.t.checked_sub_duration(other)? })
+        }
+    }
+
+    impl From<libc::timeval> for SystemTime {
+        fn from(t: libc::timeval) -> SystemTime {
+            SystemTime::from(libc::timespec {
+                tv_sec: t.tv_sec,
+                tv_nsec: (t.tv_usec * 1000) as libc::c_long,
+            })
+        }
+    }
+
+    impl From<libc::timespec> for SystemTime {
+        fn from(t: libc::timespec) -> SystemTime {
+            SystemTime { t: Timespec { t } }
+        }
+    }
+
+    impl fmt::Debug for SystemTime {
+        fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+            f.debug_struct("SystemTime")
+                .field("tv_sec", &self.t.t.tv_sec)
+                .field("tv_nsec", &self.t.t.tv_nsec)
+                .finish()
+        }
+    }
+
+    fn checked_dur2intervals(dur: &Duration) -> Option<u64> {
+        let nanos =
+            dur.as_secs().checked_mul(NSEC_PER_SEC)?.checked_add(dur.subsec_nanos() as u64)?;
+        let info = info();
+        Some(mul_div_u64(nanos, info.denom as u64, info.numer as u64))
+    }
+
+    fn info() -> mach_timebase_info {
+        static mut INFO: mach_timebase_info = mach_timebase_info { numer: 0, denom: 0 };
+        static STATE: AtomicUsize = AtomicUsize::new(0);
+
+        unsafe {
+            // If a previous thread has filled in this global state, use that.
+            if STATE.load(SeqCst) == 2 {
+                return INFO;
+            }
+
+            // ... otherwise learn for ourselves ...
+            let mut info = mem::zeroed();
+            extern "C" {
+                fn mach_timebase_info(info: mach_timebase_info_t) -> kern_return_t;
+            }
+
+            mach_timebase_info(&mut info);
+
+            // ... and attempt to be the one thread that stores it globally for
+            // all other threads
+            if STATE.compare_exchange(0, 1, SeqCst, SeqCst).is_ok() {
+                INFO = info;
+                STATE.store(2, SeqCst);
+            }
+            return info;
+        }
+    }
+}
+
+#[cfg(not(any(target_os = "macos", target_os = "ios")))]
+mod inner {
+    use crate::fmt;
+    use crate::sys::cvt;
+    use crate::time::Duration;
+
+    use super::Timespec;
+
+    #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+    pub struct Instant {
+        t: Timespec,
+    }
+
+    #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+    pub struct SystemTime {
+        t: Timespec,
+    }
+
+    pub const UNIX_EPOCH: SystemTime = SystemTime { t: Timespec::zero() };
+
+    impl Instant {
+        pub fn now() -> Instant {
+            Instant { t: now(libc::CLOCK_MONOTONIC) }
+        }
+
+        pub const fn zero() -> Instant {
+            Instant { t: Timespec::zero() }
+        }
+
+        pub fn actually_monotonic() -> bool {
+            (cfg!(target_os = "linux") && cfg!(target_arch = "x86_64"))
+                || (cfg!(target_os = "linux") && cfg!(target_arch = "x86"))
+                || cfg!(target_os = "fuchsia")
+        }
+
+        pub fn checked_sub_instant(&self, other: &Instant) -> Option<Duration> {
+            self.t.sub_timespec(&other.t).ok()
+        }
+
+        pub fn checked_add_duration(&self, other: &Duration) -> Option<Instant> {
+            Some(Instant { t: self.t.checked_add_duration(other)? })
+        }
+
+        pub fn checked_sub_duration(&self, other: &Duration) -> Option<Instant> {
+            Some(Instant { t: self.t.checked_sub_duration(other)? })
+        }
+    }
+
+    impl fmt::Debug for Instant {
+        fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+            f.debug_struct("Instant")
+                .field("tv_sec", &self.t.t.tv_sec)
+                .field("tv_nsec", &self.t.t.tv_nsec)
+                .finish()
+        }
+    }
+
+    impl SystemTime {
+        pub fn now() -> SystemTime {
+            SystemTime { t: now(libc::CLOCK_REALTIME) }
+        }
+
+        pub fn sub_time(&self, other: &SystemTime) -> Result<Duration, Duration> {
+            self.t.sub_timespec(&other.t)
+        }
+
+        pub fn checked_add_duration(&self, other: &Duration) -> Option<SystemTime> {
+            Some(SystemTime { t: self.t.checked_add_duration(other)? })
+        }
+
+        pub fn checked_sub_duration(&self, other: &Duration) -> Option<SystemTime> {
+            Some(SystemTime { t: self.t.checked_sub_duration(other)? })
+        }
+    }
+
+    impl From<libc::timespec> for SystemTime {
+        fn from(t: libc::timespec) -> SystemTime {
+            SystemTime { t: Timespec { t } }
+        }
+    }
+
+    impl fmt::Debug for SystemTime {
+        fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+            f.debug_struct("SystemTime")
+                .field("tv_sec", &self.t.t.tv_sec)
+                .field("tv_nsec", &self.t.t.tv_nsec)
+                .finish()
+        }
+    }
+
+    #[cfg(not(target_os = "dragonfly"))]
+    pub type clock_t = libc::c_int;
+    #[cfg(target_os = "dragonfly")]
+    pub type clock_t = libc::c_ulong;
+
+    fn now(clock: clock_t) -> Timespec {
+        let mut t = Timespec { t: libc::timespec { tv_sec: 0, tv_nsec: 0 } };
+        cvt(unsafe { libc::clock_gettime(clock, &mut t.t) }).unwrap();
+        t
+    }
+}