Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 222 insertions, 0 deletions

diff --git a/library/std/src/sys/unix/locks/pthread_condvar.rs b/library/std/src/sys/unix/locks/pthread_condvar.rs
new file mode 100644
index 000000000..abf27e7db
--- /dev/null
+++ b/library/std/src/sys/unix/locks/pthread_condvar.rs
@@ -0,0 +1,222 @@
+use crate::cell::UnsafeCell;
+use crate::sys::locks::{pthread_mutex, Mutex};
+use crate::sys_common::lazy_box::{LazyBox, LazyInit};
+use crate::time::Duration;
+
+pub struct Condvar {
+    inner: UnsafeCell<libc::pthread_cond_t>,
+}
+
+pub(crate) type MovableCondvar = LazyBox<Condvar>;
+
+unsafe impl Send for Condvar {}
+unsafe impl Sync for Condvar {}
+
+const TIMESPEC_MAX: libc::timespec =
+    libc::timespec { tv_sec: <libc::time_t>::MAX, tv_nsec: 1_000_000_000 - 1 };
+
+fn saturating_cast_to_time_t(value: u64) -> libc::time_t {
+    if value > <libc::time_t>::MAX as u64 { <libc::time_t>::MAX } else { value as libc::time_t }
+}
+
+impl LazyInit for Condvar {
+    fn init() -> Box<Self> {
+        let mut condvar = Box::new(Self::new());
+        unsafe { condvar.init() };
+        condvar
+    }
+}
+
+impl Condvar {
+    pub const fn new() -> Condvar {
+        // Might be moved and address is changing it is better to avoid
+        // initialization of potentially opaque OS data before it landed
+        Condvar { inner: UnsafeCell::new(libc::PTHREAD_COND_INITIALIZER) }
+    }
+
+    #[cfg(any(
+        target_os = "macos",
+        target_os = "ios",
+        target_os = "watchos",
+        target_os = "l4re",
+        target_os = "android",
+        target_os = "redox"
+    ))]
+    unsafe fn init(&mut self) {}
+
+    // NOTE: ESP-IDF's PTHREAD_COND_INITIALIZER support is not released yet
+    // So on that platform, init() should always be called
+    // Moreover, that platform does not have pthread_condattr_setclock support,
+    // hence that initialization should be skipped as well
+    //
+    // Similar story for the 3DS (horizon).
+    #[cfg(any(target_os = "espidf", target_os = "horizon"))]
+    unsafe fn init(&mut self) {
+        let r = libc::pthread_cond_init(self.inner.get(), crate::ptr::null());
+        assert_eq!(r, 0);
+    }
+
+    #[cfg(not(any(
+        target_os = "macos",
+        target_os = "ios",
+        target_os = "watchos",
+        target_os = "l4re",
+        target_os = "android",
+        target_os = "redox",
+        target_os = "espidf",
+        target_os = "horizon"
+    )))]
+    unsafe fn init(&mut self) {
+        use crate::mem::MaybeUninit;
+        let mut attr = MaybeUninit::<libc::pthread_condattr_t>::uninit();
+        let r = libc::pthread_condattr_init(attr.as_mut_ptr());
+        assert_eq!(r, 0);
+        let r = libc::pthread_condattr_setclock(attr.as_mut_ptr(), libc::CLOCK_MONOTONIC);
+        assert_eq!(r, 0);
+        let r = libc::pthread_cond_init(self.inner.get(), attr.as_ptr());
+        assert_eq!(r, 0);
+        let r = libc::pthread_condattr_destroy(attr.as_mut_ptr());
+        assert_eq!(r, 0);
+    }
+
+    #[inline]
+    pub unsafe fn notify_one(&self) {
+        let r = libc::pthread_cond_signal(self.inner.get());
+        debug_assert_eq!(r, 0);
+    }
+
+    #[inline]
+    pub unsafe fn notify_all(&self) {
+        let r = libc::pthread_cond_broadcast(self.inner.get());
+        debug_assert_eq!(r, 0);
+    }
+
+    #[inline]
+    pub unsafe fn wait(&self, mutex: &Mutex) {
+        let r = libc::pthread_cond_wait(self.inner.get(), pthread_mutex::raw(mutex));
+        debug_assert_eq!(r, 0);
+    }
+
+    // This implementation is used on systems that support pthread_condattr_setclock
+    // where we configure condition variable to use monotonic clock (instead of
+    // default system clock). This approach avoids all problems that result
+    // from changes made to the system time.
+    #[cfg(not(any(
+        target_os = "macos",
+        target_os = "ios",
+        target_os = "watchos",
+        target_os = "android",
+        target_os = "espidf",
+        target_os = "horizon"
+    )))]
+    pub unsafe fn wait_timeout(&self, mutex: &Mutex, dur: Duration) -> bool {
+        use crate::mem;
+
+        let mut now: libc::timespec = mem::zeroed();
+        let r = libc::clock_gettime(libc::CLOCK_MONOTONIC, &mut now);
+        assert_eq!(r, 0);
+
+        // Nanosecond calculations can't overflow because both values are below 1e9.
+        let nsec = dur.subsec_nanos() + now.tv_nsec as u32;
+
+        let sec = saturating_cast_to_time_t(dur.as_secs())
+            .checked_add((nsec / 1_000_000_000) as libc::time_t)
+            .and_then(|s| s.checked_add(now.tv_sec));
+        let nsec = nsec % 1_000_000_000;
+
+        let timeout =
+            sec.map(|s| libc::timespec { tv_sec: s, tv_nsec: nsec as _ }).unwrap_or(TIMESPEC_MAX);
+
+        let r = libc::pthread_cond_timedwait(self.inner.get(), pthread_mutex::raw(mutex), &timeout);
+        assert!(r == libc::ETIMEDOUT || r == 0);
+        r == 0
+    }
+
+    // This implementation is modeled after libcxx's condition_variable
+    // https://github.com/llvm-mirror/libcxx/blob/release_35/src/condition_variable.cpp#L46
+    // https://github.com/llvm-mirror/libcxx/blob/release_35/include/__mutex_base#L367
+    #[cfg(any(
+        target_os = "macos",
+        target_os = "ios",
+        target_os = "watchos",
+        target_os = "android",
+        target_os = "espidf",
+        target_os = "horizon"
+    ))]
+    pub unsafe fn wait_timeout(&self, mutex: &Mutex, mut dur: Duration) -> bool {
+        use crate::ptr;
+        use crate::time::Instant;
+
+        // 1000 years
+        let max_dur = Duration::from_secs(1000 * 365 * 86400);
+
+        if dur > max_dur {
+            // OSX implementation of `pthread_cond_timedwait` is buggy
+            // with super long durations. When duration is greater than
+            // 0x100_0000_0000_0000 seconds, `pthread_cond_timedwait`
+            // in macOS Sierra return error 316.
+            //
+            // This program demonstrates the issue:
+            // https://gist.github.com/stepancheg/198db4623a20aad2ad7cddb8fda4a63c
+            //
+            // To work around this issue, and possible bugs of other OSes, timeout
+            // is clamped to 1000 years, which is allowable per the API of `wait_timeout`
+            // because of spurious wakeups.
+
+            dur = max_dur;
+        }
+
+        // First, figure out what time it currently is, in both system and
+        // stable time.  pthread_cond_timedwait uses system time, but we want to
+        // report timeout based on stable time.
+        let mut sys_now = libc::timeval { tv_sec: 0, tv_usec: 0 };
+        let stable_now = Instant::now();
+        let r = libc::gettimeofday(&mut sys_now, ptr::null_mut());
+        debug_assert_eq!(r, 0);
+
+        let nsec = dur.subsec_nanos() as libc::c_long + (sys_now.tv_usec * 1000) as libc::c_long;
+        let extra = (nsec / 1_000_000_000) as libc::time_t;
+        let nsec = nsec % 1_000_000_000;
+        let seconds = saturating_cast_to_time_t(dur.as_secs());
+
+        let timeout = sys_now
+            .tv_sec
+            .checked_add(extra)
+            .and_then(|s| s.checked_add(seconds))
+            .map(|s| libc::timespec { tv_sec: s, tv_nsec: nsec })
+            .unwrap_or(TIMESPEC_MAX);
+
+        // And wait!
+        let r = libc::pthread_cond_timedwait(self.inner.get(), pthread_mutex::raw(mutex), &timeout);
+        debug_assert!(r == libc::ETIMEDOUT || r == 0);
+
+        // ETIMEDOUT is not a totally reliable method of determining timeout due
+        // to clock shifts, so do the check ourselves
+        stable_now.elapsed() < dur
+    }
+
+    #[inline]
+    #[cfg(not(target_os = "dragonfly"))]
+    unsafe fn destroy(&mut self) {
+        let r = libc::pthread_cond_destroy(self.inner.get());
+        debug_assert_eq!(r, 0);
+    }
+
+    #[inline]
+    #[cfg(target_os = "dragonfly")]
+    unsafe fn destroy(&mut self) {
+        let r = libc::pthread_cond_destroy(self.inner.get());
+        // On DragonFly pthread_cond_destroy() returns EINVAL if called on
+        // a condvar that was just initialized with
+        // libc::PTHREAD_COND_INITIALIZER. Once it is used or
+        // pthread_cond_init() is called, this behaviour no longer occurs.
+        debug_assert!(r == 0 || r == libc::EINVAL);
+    }
+}
+
+impl Drop for Condvar {
+    #[inline]
+    fn drop(&mut self) {
+        unsafe { self.destroy() };
+    }
+}