std: move time implementations to sys (UNIX)

Now for UNIX: `Timespec` is also used for things like futex or `Condvar` timeouts, so it stays in the PAL along with some related definitions. Everything else is `SystemTime`- and `Instant`-specific, and is thus moved to `sys::time`.

Author: joboet

library/std/src/sys/fs/unix.rs

@@ -1822,7 +1822,7 @@ impl File {
             _ => {
                 #[cfg(all(target_os = "linux", target_env = "gnu", target_pointer_width = "32", not(target_arch = "riscv32")))]
                 {
-                    use crate::sys::{time::__timespec64, weak::weak};
+                    use crate::sys::pal::{time::__timespec64, weak::weak};
 
                     // Added in glibc 2.34
                     weak!(
@@ -2258,7 +2258,7 @@ fn set_times_impl(p: &CStr, times: FileTimes, follow_symlinks: bool) -> io::Resu
             let flags = if follow_symlinks { 0 } else { libc::AT_SYMLINK_NOFOLLOW };
             #[cfg(all(target_os = "linux", target_env = "gnu", target_pointer_width = "32", not(target_arch = "riscv32")))]
             {
-                use crate::sys::{time::__timespec64, weak::weak};
+                use crate::sys::pal::{time::__timespec64, weak::weak};
 
                 // Added in glibc 2.34
                 weak!(

library/std/src/sys/pal/unix/time.rs

@@ -1,11 +1,10 @@
 use core::num::niche_types::Nanoseconds;
 
-use crate::sys::AsInner;
+use crate::io;
 use crate::time::Duration;
-use crate::{fmt, io};
 
 const NSEC_PER_SEC: u64 = 1_000_000_000;
-pub const UNIX_EPOCH: SystemTime = SystemTime { t: Timespec::zero() };
+
 #[allow(dead_code)] // Used for pthread condvar timeouts
 pub const TIMESPEC_MAX: libc::timespec =
     libc::timespec { tv_sec: <libc::time_t>::MAX, tv_nsec: 1_000_000_000 - 1 };
@@ -18,60 +17,19 @@ pub(in crate::sys) const TIMESPEC_MAX_CAPPED: libc::timespec = libc::timespec {
     tv_nsec: (u64::MAX % NSEC_PER_SEC) as i64,
 };
 
-#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
-pub struct SystemTime {
-    pub(crate) t: Timespec,
-}
-
 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub(crate) struct Timespec {
-    tv_sec: i64,
-    tv_nsec: Nanoseconds,
-}
-
-impl SystemTime {
-    pub const MAX: SystemTime = SystemTime { t: Timespec::MAX };
-
-    pub const MIN: SystemTime = SystemTime { t: Timespec::MIN };
-
-    #[cfg_attr(any(target_os = "horizon", target_os = "hurd"), allow(unused))]
-    pub fn new(tv_sec: i64, tv_nsec: i64) -> Result<SystemTime, io::Error> {
-        Ok(SystemTime { t: Timespec::new(tv_sec, tv_nsec)? })
-    }
-
-    pub fn now() -> SystemTime {
-        SystemTime { t: Timespec::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 fmt::Debug for SystemTime {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        f.debug_struct("SystemTime")
-            .field("tv_sec", &self.t.tv_sec)
-            .field("tv_nsec", &self.t.tv_nsec)
-            .finish()
-    }
+    pub tv_sec: i64,
+    pub tv_nsec: Nanoseconds,
 }
 
 impl Timespec {
-    const MAX: Timespec = unsafe { Self::new_unchecked(i64::MAX, 1_000_000_000 - 1) };
+    pub const MAX: Timespec = unsafe { Self::new_unchecked(i64::MAX, 1_000_000_000 - 1) };
 
     // As described below, on Apple OS, dates before epoch are represented differently.
     // This is not an issue here however, because we are using tv_sec = i64::MIN,
     // which will cause the compatibility wrapper to not be executed at all.
-    const MIN: Timespec = unsafe { Self::new_unchecked(i64::MIN, 0) };
+    pub const MIN: Timespec = unsafe { Self::new_unchecked(i64::MIN, 0) };
 
     const unsafe fn new_unchecked(tv_sec: i64, tv_nsec: i64) -> Timespec {
         Timespec { tv_sec, tv_nsec: unsafe { Nanoseconds::new_unchecked(tv_nsec as u32) } }
@@ -81,7 +39,7 @@ impl Timespec {
         unsafe { Self::new_unchecked(0, 0) }
     }
 
-    const fn new(tv_sec: i64, tv_nsec: i64) -> Result<Timespec, io::Error> {
+    pub const fn new(tv_sec: i64, tv_nsec: i64) -> Result<Timespec, io::Error> {
         // On Apple OS, dates before epoch are represented differently than on other
         // Unix platforms: e.g. 1/10th of a second before epoch is represented as `seconds=-1`
         // and `nanoseconds=100_000_000` on other platforms, but is `seconds=0` and
@@ -263,64 +221,3 @@ impl __timespec64 {
         Self { tv_sec, tv_nsec, _padding: 0 }
     }
 }
-
-#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
-pub struct Instant {
-    t: Timespec,
-}
-
-impl Instant {
-    #[cfg(target_vendor = "apple")]
-    pub(crate) const CLOCK_ID: libc::clockid_t = libc::CLOCK_UPTIME_RAW;
-    #[cfg(not(target_vendor = "apple"))]
-    pub(crate) const CLOCK_ID: libc::clockid_t = libc::CLOCK_MONOTONIC;
-    pub fn now() -> Instant {
-        // https://pubs.opengroup.org/onlinepubs/9799919799/functions/clock_getres.html
-        //
-        // CLOCK_UPTIME_RAW   clock that increments monotonically, in the same man-
-        //                    ner as CLOCK_MONOTONIC_RAW, but that does not incre-
-        //                    ment while the system is asleep.  The returned value
-        //                    is identical to the result of mach_absolute_time()
-        //                    after the appropriate mach_timebase conversion is
-        //                    applied.
-        //
-        // Instant on macos was historically implemented using mach_absolute_time;
-        // we preserve this value domain out of an abundance of caution.
-        Instant { t: Timespec::now(Self::CLOCK_ID) }
-    }
-
-    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)? })
-    }
-
-    #[cfg_attr(
-        not(target_os = "linux"),
-        allow(unused, reason = "needed by the `sleep_until` on some unix platforms")
-    )]
-    pub(crate) fn into_timespec(self) -> Timespec {
-        self.t
-    }
-}
-
-impl AsInner<Timespec> for Instant {
-    fn as_inner(&self) -> &Timespec {
-        &self.t
-    }
-}
-
-impl fmt::Debug for Instant {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        f.debug_struct("Instant")
-            .field("tv_sec", &self.t.tv_sec)
-            .field("tv_nsec", &self.t.tv_nsec)
-            .finish()
-    }
-}

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

@@ -14,6 +14,10 @@ cfg_select! {
         mod uefi;
         use uefi as imp;
     }
+    target_family = "unix" => {
+        mod unix;
+        use unix as imp;
+    }
     target_os = "vexos" => {
         mod vexos;
         #[expect(unused)]

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

@@ -0,0 +1,108 @@
+use crate::sys::AsInner;
+use crate::sys::pal::time::Timespec;
+use crate::time::Duration;
+use crate::{fmt, io};
+
+pub const UNIX_EPOCH: SystemTime = SystemTime { t: Timespec::zero() };
+
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct SystemTime {
+    pub(crate) t: Timespec,
+}
+
+impl SystemTime {
+    pub const MAX: SystemTime = SystemTime { t: Timespec::MAX };
+
+    pub const MIN: SystemTime = SystemTime { t: Timespec::MIN };
+
+    #[cfg_attr(any(target_os = "horizon", target_os = "hurd"), allow(unused))]
+    pub fn new(tv_sec: i64, tv_nsec: i64) -> Result<SystemTime, io::Error> {
+        Ok(SystemTime { t: Timespec::new(tv_sec, tv_nsec)? })
+    }
+
+    pub fn now() -> SystemTime {
+        SystemTime { t: Timespec::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 fmt::Debug for SystemTime {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("SystemTime")
+            .field("tv_sec", &self.t.tv_sec)
+            .field("tv_nsec", &self.t.tv_nsec)
+            .finish()
+    }
+}
+
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct Instant {
+    t: Timespec,
+}
+
+impl Instant {
+    #[cfg(target_vendor = "apple")]
+    pub(crate) const CLOCK_ID: libc::clockid_t = libc::CLOCK_UPTIME_RAW;
+    #[cfg(not(target_vendor = "apple"))]
+    pub(crate) const CLOCK_ID: libc::clockid_t = libc::CLOCK_MONOTONIC;
+    pub fn now() -> Instant {
+        // https://pubs.opengroup.org/onlinepubs/9799919799/functions/clock_getres.html
+        //
+        // CLOCK_UPTIME_RAW   clock that increments monotonically, in the same man-
+        //                    ner as CLOCK_MONOTONIC_RAW, but that does not incre-
+        //                    ment while the system is asleep.  The returned value
+        //                    is identical to the result of mach_absolute_time()
+        //                    after the appropriate mach_timebase conversion is
+        //                    applied.
+        //
+        // Instant on macos was historically implemented using mach_absolute_time;
+        // we preserve this value domain out of an abundance of caution.
+        Instant { t: Timespec::now(Self::CLOCK_ID) }
+    }
+
+    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)? })
+    }
+
+    #[cfg_attr(
+        not(target_os = "linux"),
+        allow(unused, reason = "needed by the `sleep_until` on some unix platforms")
+    )]
+    pub(crate) fn into_timespec(self) -> Timespec {
+        self.t
+    }
+}
+
+impl AsInner<Timespec> for Instant {
+    fn as_inner(&self) -> &Timespec {
+        &self.t
+    }
+}
+
+impl fmt::Debug for Instant {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("Instant")
+            .field("tv_sec", &self.t.tv_sec)
+            .field("tv_nsec", &self.t.tv_nsec)
+            .finish()
+    }
+}