1 files changed, 0 insertions, 155 deletions
diff --git a/vendor/crossbeam-utils/src/atomic/seq_lock_wide.rs b/vendor/crossbeam-utils/src/atomic/seq_lock_wide.rs
deleted file mode 100644
index ef5d94a..0000000
--- a/vendor/crossbeam-utils/src/atomic/seq_lock_wide.rs
+++ /dev/null
@@ -1,155 +0,0 @@
-use core::mem;
-use core::sync::atomic::{self, AtomicUsize, Ordering};
-
-use crate::Backoff;
-
-/// A simple stamped lock.
-///
-/// The state is represented as two `AtomicUsize`: `state_hi` for high bits and `state_lo` for low
-/// bits.
-pub(crate) struct SeqLock {
-    /// The high bits of the current state of the lock.
-    state_hi: AtomicUsize,
-
-    /// The low bits of the current state of the lock.
-    ///
-    /// All bits except the least significant one hold the current stamp. When locked, the state_lo
-    /// equals 1 and doesn't contain a valid stamp.
-    state_lo: AtomicUsize,
-}
-
-impl SeqLock {
-    pub(crate) const fn new() -> Self {
-        Self {
-            state_hi: AtomicUsize::new(0),
-            state_lo: AtomicUsize::new(0),
-        }
-    }
-
-    /// If not locked, returns the current stamp.
-    ///
-    /// This method should be called before optimistic reads.
-    #[inline]
-    pub(crate) fn optimistic_read(&self) -> Option<(usize, usize)> {
-        // The acquire loads from `state_hi` and `state_lo` synchronize with the release stores in
-        // `SeqLockWriteGuard::drop`.
-        //
-        // As a consequence, we can make sure that (1) all writes within the era of `state_hi - 1`
-        // happens before now; and therefore, (2) if `state_lo` is even, all writes within the
-        // critical section of (`state_hi`, `state_lo`) happens before now.
-        let state_hi = self.state_hi.load(Ordering::Acquire);
-        let state_lo = self.state_lo.load(Ordering::Acquire);
-        if state_lo == 1 {
-            None
-        } else {
-            Some((state_hi, state_lo))
-        }
-    }
-
-    /// Returns `true` if the current stamp is equal to `stamp`.
-    ///
-    /// This method should be called after optimistic reads to check whether they are valid. The
-    /// argument `stamp` should correspond to the one returned by method `optimistic_read`.
-    #[inline]
-    pub(crate) fn validate_read(&self, stamp: (usize, usize)) -> bool {
-        // Thanks to the fence, if we're noticing any modification to the data at the critical
-        // section of `(a, b)`, then the critical section's write of 1 to state_lo should be
-        // visible.
-        atomic::fence(Ordering::Acquire);
-
-        // So if `state_lo` coincides with `stamp.1`, then either (1) we're noticing no modification
-        // to the data after the critical section of `(stamp.0, stamp.1)`, or (2) `state_lo` wrapped
-        // around.
-        //
-        // If (2) is the case, the acquire ordering ensures we see the new value of `state_hi`.
-        let state_lo = self.state_lo.load(Ordering::Acquire);
-
-        // If (2) is the case and `state_hi` coincides with `stamp.0`, then `state_hi` also wrapped
-        // around, which we give up to correctly validate the read.
-        let state_hi = self.state_hi.load(Ordering::Relaxed);
-
-        // Except for the case that both `state_hi` and `state_lo` wrapped around, the following
-        // condition implies that we're noticing no modification to the data after the critical
-        // section of `(stamp.0, stamp.1)`.
-        (state_hi, state_lo) == stamp
-    }
-
-    /// Grabs the lock for writing.
-    #[inline]
-    pub(crate) fn write(&'static self) -> SeqLockWriteGuard {
-        let backoff = Backoff::new();
-        loop {
-            let previous = self.state_lo.swap(1, Ordering::Acquire);
-
-            if previous != 1 {
-                // To synchronize with the acquire fence in `validate_read` via any modification to
-                // the data at the critical section of `(state_hi, previous)`.
-                atomic::fence(Ordering::Release);
-
-                return SeqLockWriteGuard {
-                    lock: self,
-                    state_lo: previous,
-                };
-            }
-
-            backoff.snooze();
-        }
-    }
-}
-
-/// An RAII guard that releases the lock and increments the stamp when dropped.
-pub(crate) struct SeqLockWriteGuard {
-    /// The parent lock.
-    lock: &'static SeqLock,
-
-    /// The stamp before locking.
-    state_lo: usize,
-}
-
-impl SeqLockWriteGuard {
-    /// Releases the lock without incrementing the stamp.
-    #[inline]
-    pub(crate) fn abort(self) {
-        self.lock.state_lo.store(self.state_lo, Ordering::Release);
-        mem::forget(self);
-    }
-}
-
-impl Drop for SeqLockWriteGuard {
-    #[inline]
-    fn drop(&mut self) {
-        let state_lo = self.state_lo.wrapping_add(2);
-
-        // Increase the high bits if the low bits wrap around.
-        //
-        // Release ordering for synchronizing with `optimistic_read`.
-        if state_lo == 0 {
-            let state_hi = self.lock.state_hi.load(Ordering::Relaxed);
-            self.lock
-                .state_hi
-                .store(state_hi.wrapping_add(1), Ordering::Release);
-        }
-
-        // Release the lock and increment the stamp.
-        //
-        // Release ordering for synchronizing with `optimistic_read`.
-        self.lock.state_lo.store(state_lo, Ordering::Release);
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::SeqLock;
-
-    #[test]
-    fn test_abort() {
-        static LK: SeqLock = SeqLock::new();
-        let before = LK.optimistic_read().unwrap();
-        {
-            let guard = LK.write();
-            guard.abort();
-        }
-        let after = LK.optimistic_read().unwrap();
-        assert_eq!(before, after, "aborted write does not update the stamp");
-    }
-}