1 files changed, 0 insertions, 147 deletions
diff --git a/vendor/portable-atomic/src/imp/fallback/seq_lock.rs b/vendor/portable-atomic/src/imp/fallback/seq_lock.rs
deleted file mode 100644
index fb6803f..0000000
--- a/vendor/portable-atomic/src/imp/fallback/seq_lock.rs
+++ /dev/null
@@ -1,147 +0,0 @@
-// SPDX-License-Identifier: Apache-2.0 OR MIT
-
-// Adapted from https://github.com/crossbeam-rs/crossbeam/blob/crossbeam-utils-0.8.7/crossbeam-utils/src/atomic/seq_lock.rs.
-
-use core::{
-    mem::ManuallyDrop,
-    sync::atomic::{self, Ordering},
-};
-
-use super::utils::Backoff;
-
-// See mod.rs for details.
-#[cfg(any(target_pointer_width = "16", target_pointer_width = "32"))]
-pub(super) use core::sync::atomic::AtomicU64 as AtomicStamp;
-#[cfg(not(any(target_pointer_width = "16", target_pointer_width = "32")))]
-pub(super) use core::sync::atomic::AtomicUsize as AtomicStamp;
-#[cfg(not(any(target_pointer_width = "16", target_pointer_width = "32")))]
-pub(super) type Stamp = usize;
-#[cfg(any(target_pointer_width = "16", target_pointer_width = "32"))]
-pub(super) type Stamp = u64;
-
-// See mod.rs for details.
-pub(super) type AtomicChunk = AtomicStamp;
-pub(super) type Chunk = Stamp;
-
-/// A simple stamped lock.
-pub(super) struct SeqLock {
-    /// The current state of the lock.
-    ///
-    /// All bits except the least significant one hold the current stamp. When locked, the state
-    /// equals 1 and doesn't contain a valid stamp.
-    state: AtomicStamp,
-}
-
-impl SeqLock {
-    #[inline]
-    pub(super) const fn new() -> Self {
-        Self { state: AtomicStamp::new(0) }
-    }
-
-    /// If not locked, returns the current stamp.
-    ///
-    /// This method should be called before optimistic reads.
-    #[inline]
-    pub(super) fn optimistic_read(&self) -> Option<Stamp> {
-        let state = self.state.load(Ordering::Acquire);
-        if state == 1 {
-            None
-        } else {
-            Some(state)
-        }
-    }
-
-    /// 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(super) fn validate_read(&self, stamp: Stamp) -> bool {
-        atomic::fence(Ordering::Acquire);
-        self.state.load(Ordering::Relaxed) == stamp
-    }
-
-    /// Grabs the lock for writing.
-    #[inline]
-    pub(super) fn write(&self) -> SeqLockWriteGuard<'_> {
-        let mut backoff = Backoff::new();
-        loop {
-            let previous = self.state.swap(1, Ordering::Acquire);
-
-            if previous != 1 {
-                atomic::fence(Ordering::Release);
-
-                return SeqLockWriteGuard { lock: self, state: previous };
-            }
-
-            while self.state.load(Ordering::Relaxed) == 1 {
-                backoff.snooze();
-            }
-        }
-    }
-}
-
-/// An RAII guard that releases the lock and increments the stamp when dropped.
-#[must_use]
-pub(super) struct SeqLockWriteGuard<'a> {
-    /// The parent lock.
-    lock: &'a SeqLock,
-
-    /// The stamp before locking.
-    state: Stamp,
-}
-
-impl SeqLockWriteGuard<'_> {
-    /// Releases the lock without incrementing the stamp.
-    #[inline]
-    pub(super) fn abort(self) {
-        // We specifically don't want to call drop(), since that's
-        // what increments the stamp.
-        let this = ManuallyDrop::new(self);
-
-        // Restore the stamp.
-        //
-        // Release ordering for synchronizing with `optimistic_read`.
-        this.lock.state.store(this.state, Ordering::Release);
-    }
-}
-
-impl Drop for SeqLockWriteGuard<'_> {
-    #[inline]
-    fn drop(&mut self) {
-        // Release the lock and increment the stamp.
-        //
-        // Release ordering for synchronizing with `optimistic_read`.
-        self.lock.state.store(self.state.wrapping_add(2), Ordering::Release);
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::SeqLock;
-
-    #[test]
-    fn smoke() {
-        let lock = SeqLock::new();
-        let before = lock.optimistic_read().unwrap();
-        assert!(lock.validate_read(before));
-        {
-            let _guard = lock.write();
-        }
-        assert!(!lock.validate_read(before));
-        let after = lock.optimistic_read().unwrap();
-        assert_ne!(before, after);
-    }
-
-    #[test]
-    fn test_abort() {
-        let lock = SeqLock::new();
-        let before = lock.optimistic_read().unwrap();
-        {
-            let guard = lock.write();
-            guard.abort();
-        }
-        let after = lock.optimistic_read().unwrap();
-        assert_eq!(before, after, "aborted write does not update the stamp");
-    }
-}