2 use crate::time::Duration;
4 pub use self::inner::Instant;
6 const NSEC_PER_SEC: u64 = 1_000_000_000;
7 pub const UNIX_EPOCH: SystemTime = SystemTime { t: Timespec::zero() };
8 #[allow(dead_code)] // Used for pthread condvar timeouts
9 pub const TIMESPEC_MAX: libc::timespec =
10 libc::timespec { tv_sec: <libc::time_t>::MAX, tv_nsec: 1_000_000_000 - 1 };
12 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
14 #[rustc_layout_scalar_valid_range_start(0)]
15 #[rustc_layout_scalar_valid_range_end(999_999_999)]
16 struct Nanoseconds(u32);
18 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
19 pub struct SystemTime {
20 pub(in crate::sys::unix) t: Timespec,
23 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
24 pub(in crate::sys::unix) struct Timespec {
30 #[cfg_attr(target_os = "horizon", allow(unused))]
31 pub fn new(tv_sec: i64, tv_nsec: i64) -> SystemTime {
32 SystemTime { t: Timespec::new(tv_sec, tv_nsec) }
35 pub fn sub_time(&self, other: &SystemTime) -> Result<Duration, Duration> {
36 self.t.sub_timespec(&other.t)
39 pub fn checked_add_duration(&self, other: &Duration) -> Option<SystemTime> {
40 Some(SystemTime { t: self.t.checked_add_duration(other)? })
43 pub fn checked_sub_duration(&self, other: &Duration) -> Option<SystemTime> {
44 Some(SystemTime { t: self.t.checked_sub_duration(other)? })
48 impl From<libc::timespec> for SystemTime {
49 fn from(t: libc::timespec) -> SystemTime {
50 SystemTime { t: Timespec::from(t) }
54 impl fmt::Debug for SystemTime {
55 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
56 f.debug_struct("SystemTime")
57 .field("tv_sec", &self.t.tv_sec)
58 .field("tv_nsec", &self.t.tv_nsec.0)
64 pub const fn zero() -> Timespec {
68 const fn new(tv_sec: i64, tv_nsec: i64) -> Timespec {
69 assert!(tv_nsec >= 0 && tv_nsec < NSEC_PER_SEC as i64);
70 // SAFETY: The assert above checks tv_nsec is within the valid range
71 Timespec { tv_sec, tv_nsec: unsafe { Nanoseconds(tv_nsec as u32) } }
74 pub fn sub_timespec(&self, other: &Timespec) -> Result<Duration, Duration> {
76 // NOTE(eddyb) two aspects of this `if`-`else` are required for LLVM
77 // to optimize it into a branchless form (see also #75545):
79 // 1. `self.tv_sec - other.tv_sec` shows up as a common expression
80 // in both branches, i.e. the `else` must have its `- 1`
81 // subtraction after the common one, not interleaved with it
82 // (it used to be `self.tv_sec - 1 - other.tv_sec`)
84 // 2. the `Duration::new` call (or any other additional complexity)
85 // is outside of the `if`-`else`, not duplicated in both branches
87 // Ideally this code could be rearranged such that it more
88 // directly expresses the lower-cost behavior we want from it.
89 let (secs, nsec) = if self.tv_nsec.0 >= other.tv_nsec.0 {
90 ((self.tv_sec - other.tv_sec) as u64, self.tv_nsec.0 - other.tv_nsec.0)
93 (self.tv_sec - other.tv_sec - 1) as u64,
94 self.tv_nsec.0 + (NSEC_PER_SEC as u32) - other.tv_nsec.0,
98 Ok(Duration::new(secs, nsec))
100 match other.sub_timespec(self) {
107 pub fn checked_add_duration(&self, other: &Duration) -> Option<Timespec> {
110 .try_into() // <- target type would be `i64`
112 .and_then(|secs| self.tv_sec.checked_add(secs))?;
114 // Nano calculations can't overflow because nanos are <1B which fit
116 let mut nsec = other.subsec_nanos() + self.tv_nsec.0;
117 if nsec >= NSEC_PER_SEC as u32 {
118 nsec -= NSEC_PER_SEC as u32;
119 secs = secs.checked_add(1)?;
121 Some(Timespec::new(secs, nsec as i64))
124 pub fn checked_sub_duration(&self, other: &Duration) -> Option<Timespec> {
127 .try_into() // <- target type would be `i64`
129 .and_then(|secs| self.tv_sec.checked_sub(secs))?;
131 // Similar to above, nanos can't overflow.
132 let mut nsec = self.tv_nsec.0 as i32 - other.subsec_nanos() as i32;
134 nsec += NSEC_PER_SEC as i32;
135 secs = secs.checked_sub(1)?;
137 Some(Timespec::new(secs, nsec as i64))
141 pub fn to_timespec(&self) -> Option<libc::timespec> {
142 Some(libc::timespec {
143 tv_sec: self.tv_sec.try_into().ok()?,
144 tv_nsec: self.tv_nsec.0.try_into().ok()?,
149 impl From<libc::timespec> for Timespec {
150 fn from(t: libc::timespec) -> Timespec {
151 Timespec::new(t.tv_sec as i64, t.tv_nsec as i64)
156 all(target_os = "macos", any(not(target_arch = "aarch64"))),
158 target_os = "watchos"
161 use crate::sync::atomic::{AtomicU64, Ordering};
163 use crate::sys_common::mul_div_u64;
164 use crate::time::Duration;
166 use super::{SystemTime, Timespec, NSEC_PER_SEC};
168 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
174 #[derive(Copy, Clone)]
175 struct mach_timebase_info {
179 type mach_timebase_info_t = *mut mach_timebase_info;
180 type kern_return_t = libc::c_int;
183 pub fn now() -> Instant {
185 fn mach_absolute_time() -> u64;
187 Instant { t: unsafe { mach_absolute_time() } }
190 pub fn checked_sub_instant(&self, other: &Instant) -> Option<Duration> {
191 let diff = self.t.checked_sub(other.t)?;
193 let nanos = mul_div_u64(diff, info.numer as u64, info.denom as u64);
194 Some(Duration::new(nanos / NSEC_PER_SEC, (nanos % NSEC_PER_SEC) as u32))
197 pub fn checked_add_duration(&self, other: &Duration) -> Option<Instant> {
198 Some(Instant { t: self.t.checked_add(checked_dur2intervals(other)?)? })
201 pub fn checked_sub_duration(&self, other: &Duration) -> Option<Instant> {
202 Some(Instant { t: self.t.checked_sub(checked_dur2intervals(other)?)? })
207 pub fn now() -> SystemTime {
210 let mut s = libc::timeval { tv_sec: 0, tv_usec: 0 };
211 cvt(unsafe { libc::gettimeofday(&mut s, ptr::null_mut()) }).unwrap();
212 return SystemTime::from(s);
216 impl From<libc::timeval> for Timespec {
217 fn from(t: libc::timeval) -> Timespec {
218 Timespec::new(t.tv_sec as i64, 1000 * t.tv_usec as i64)
222 impl From<libc::timeval> for SystemTime {
223 fn from(t: libc::timeval) -> SystemTime {
224 SystemTime { t: Timespec::from(t) }
228 fn checked_dur2intervals(dur: &Duration) -> Option<u64> {
230 dur.as_secs().checked_mul(NSEC_PER_SEC)?.checked_add(dur.subsec_nanos() as u64)?;
232 Some(mul_div_u64(nanos, info.denom as u64, info.numer as u64))
235 fn info() -> mach_timebase_info {
236 // INFO_BITS conceptually is an `Option<mach_timebase_info>`. We can do
237 // this in 64 bits because we know 0 is never a valid value for the
240 // Encoding this as a single `AtomicU64` allows us to use `Relaxed`
241 // operations, as we are only interested in the effects on a single
243 static INFO_BITS: AtomicU64 = AtomicU64::new(0);
245 // If a previous thread has initialized `INFO_BITS`, use it.
246 let info_bits = INFO_BITS.load(Ordering::Relaxed);
248 return info_from_bits(info_bits);
251 // ... otherwise learn for ourselves ...
253 fn mach_timebase_info(info: mach_timebase_info_t) -> kern_return_t;
256 let mut info = info_from_bits(0);
258 mach_timebase_info(&mut info);
260 INFO_BITS.store(info_to_bits(info), Ordering::Relaxed);
265 fn info_to_bits(info: mach_timebase_info) -> u64 {
266 ((info.denom as u64) << 32) | (info.numer as u64)
270 fn info_from_bits(bits: u64) -> mach_timebase_info {
271 mach_timebase_info { numer: bits as u32, denom: (bits >> 32) as u32 }
276 all(target_os = "macos", any(not(target_arch = "aarch64"))),
278 target_os = "watchos"
282 use crate::mem::MaybeUninit;
284 use crate::time::Duration;
286 use super::{SystemTime, Timespec};
288 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
294 pub fn now() -> Instant {
295 #[cfg(target_os = "macos")]
296 const clock_id: libc::clockid_t = libc::CLOCK_UPTIME_RAW;
297 #[cfg(not(target_os = "macos"))]
298 const clock_id: libc::clockid_t = libc::CLOCK_MONOTONIC;
299 Instant { t: Timespec::now(clock_id) }
302 pub fn checked_sub_instant(&self, other: &Instant) -> Option<Duration> {
303 self.t.sub_timespec(&other.t).ok()
306 pub fn checked_add_duration(&self, other: &Duration) -> Option<Instant> {
307 Some(Instant { t: self.t.checked_add_duration(other)? })
310 pub fn checked_sub_duration(&self, other: &Duration) -> Option<Instant> {
311 Some(Instant { t: self.t.checked_sub_duration(other)? })
315 impl fmt::Debug for Instant {
316 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
317 f.debug_struct("Instant")
318 .field("tv_sec", &self.t.tv_sec)
319 .field("tv_nsec", &self.t.tv_nsec.0)
325 pub fn now() -> SystemTime {
326 SystemTime { t: Timespec::now(libc::CLOCK_REALTIME) }
331 pub fn now(clock: libc::clockid_t) -> Timespec {
332 // Try to use 64-bit time in preparation for Y2038.
333 #[cfg(all(target_os = "linux", target_env = "gnu", target_pointer_width = "32"))]
335 use crate::sys::weak::weak;
337 // __clock_gettime64 was added to 32-bit arches in glibc 2.34,
338 // and it handles both vDSO calls and ENOSYS fallbacks itself.
339 weak!(fn __clock_gettime64(libc::clockid_t, *mut __timespec64) -> libc::c_int);
342 struct __timespec64 {
344 #[cfg(target_endian = "big")]
347 #[cfg(target_endian = "little")]
351 if let Some(clock_gettime64) = __clock_gettime64.get() {
352 let mut t = MaybeUninit::uninit();
353 cvt(unsafe { clock_gettime64(clock, t.as_mut_ptr()) }).unwrap();
354 let t = unsafe { t.assume_init() };
355 return Timespec::new(t.tv_sec, t.tv_nsec as i64);
359 let mut t = MaybeUninit::uninit();
360 cvt(unsafe { libc::clock_gettime(clock, t.as_mut_ptr()) }).unwrap();
361 Timespec::from(unsafe { t.assume_init() })