chore: delete defunct use of futures-intrusive

Author: abonander

sqlx-core/src/sync.rs

@@ -9,135 +9,3 @@ pub use async_std::sync::{Mutex as AsyncMutex, MutexGuard as AsyncMutexGuard};
 
 #[cfg(feature = "_rt-tokio")]
 pub use tokio::sync::{Mutex as AsyncMutex, MutexGuard as AsyncMutexGuard};
-
-pub struct AsyncSemaphore {
-    // We use the semaphore from futures-intrusive as the one from async-std
-    // is missing the ability to add arbitrary permits, and is not guaranteed to be fair:
-    // * https://github.com/smol-rs/async-lock/issues/22
-    // * https://github.com/smol-rs/async-lock/issues/23
-    //
-    // We're on the look-out for a replacement, however, as futures-intrusive is not maintained
-    // and there are some soundness concerns (although it turns out any intrusive future is unsound
-    // in MIRI due to the necessitated mutable aliasing):
-    // https://github.com/launchbadge/sqlx/issues/1668
-    #[cfg(all(feature = "_rt-async-std", not(feature = "_rt-tokio")))]
-    inner: futures_intrusive::sync::Semaphore,
-
-    #[cfg(feature = "_rt-tokio")]
-    inner: tokio::sync::Semaphore,
-}
-
-impl AsyncSemaphore {
-    #[track_caller]
-    pub fn new(fair: bool, permits: usize) -> Self {
-        if cfg!(not(any(feature = "_rt-async-std", feature = "_rt-tokio"))) {
-            crate::rt::missing_rt((fair, permits));
-        }
-
-        AsyncSemaphore {
-            #[cfg(all(feature = "_rt-async-std", not(feature = "_rt-tokio")))]
-            inner: futures_intrusive::sync::Semaphore::new(fair, permits),
-            #[cfg(feature = "_rt-tokio")]
-            inner: {
-                debug_assert!(fair, "Tokio only has fair permits");
-                tokio::sync::Semaphore::new(permits)
-            },
-        }
-    }
-
-    pub fn permits(&self) -> usize {
-        #[cfg(all(feature = "_rt-async-std", not(feature = "_rt-tokio")))]
-        return self.inner.permits();
-
-        #[cfg(feature = "_rt-tokio")]
-        return self.inner.available_permits();
-
-        #[cfg(not(any(feature = "_rt-async-std", feature = "_rt-tokio")))]
-        crate::rt::missing_rt(())
-    }
-
-    pub async fn acquire(&self, permits: u32) -> AsyncSemaphoreReleaser<'_> {
-        #[cfg(all(feature = "_rt-async-std", not(feature = "_rt-tokio")))]
-        return AsyncSemaphoreReleaser {
-            inner: self.inner.acquire(permits as usize).await,
-        };
-
-        #[cfg(feature = "_rt-tokio")]
-        return AsyncSemaphoreReleaser {
-            inner: self
-                .inner
-                // Weird quirk: `tokio::sync::Semaphore` mostly uses `usize` for permit counts,
-                // but `u32` for this and `try_acquire_many()`.
-                .acquire_many(permits)
-                .await
-                .expect("BUG: we do not expose the `.close()` method"),
-        };
-
-        #[cfg(not(any(feature = "_rt-async-std", feature = "_rt-tokio")))]
-        crate::rt::missing_rt(permits)
-    }
-
-    pub fn try_acquire(&self, permits: u32) -> Option<AsyncSemaphoreReleaser<'_>> {
-        #[cfg(all(feature = "_rt-async-std", not(feature = "_rt-tokio")))]
-        return Some(AsyncSemaphoreReleaser {
-            inner: self.inner.try_acquire(permits as usize)?,
-        });
-
-        #[cfg(feature = "_rt-tokio")]
-        return Some(AsyncSemaphoreReleaser {
-            inner: self.inner.try_acquire_many(permits).ok()?,
-        });
-
-        #[cfg(not(any(feature = "_rt-async-std", feature = "_rt-tokio")))]
-        crate::rt::missing_rt(permits)
-    }
-
-    pub fn release(&self, permits: usize) {
-        #[cfg(all(feature = "_rt-async-std", not(feature = "_rt-tokio")))]
-        return self.inner.release(permits);
-
-        #[cfg(feature = "_rt-tokio")]
-        return self.inner.add_permits(permits);
-
-        #[cfg(not(any(feature = "_rt-async-std", feature = "_rt-tokio")))]
-        crate::rt::missing_rt(permits)
-    }
-}
-
-pub struct AsyncSemaphoreReleaser<'a> {
-    // We use the semaphore from futures-intrusive as the one from async-std
-    // is missing the ability to add arbitrary permits, and is not guaranteed to be fair:
-    // * https://github.com/smol-rs/async-lock/issues/22
-    // * https://github.com/smol-rs/async-lock/issues/23
-    //
-    // We're on the look-out for a replacement, however, as futures-intrusive is not maintained
-    // and there are some soundness concerns (although it turns out any intrusive future is unsound
-    // in MIRI due to the necessitated mutable aliasing):
-    // https://github.com/launchbadge/sqlx/issues/1668
-    #[cfg(all(feature = "_rt-async-std", not(feature = "_rt-tokio")))]
-    inner: futures_intrusive::sync::SemaphoreReleaser<'a>,
-
-    #[cfg(feature = "_rt-tokio")]
-    inner: tokio::sync::SemaphorePermit<'a>,
-
-    #[cfg(not(any(feature = "_rt-async-std", feature = "_rt-tokio")))]
-    _phantom: std::marker::PhantomData<&'a ()>,
-}
-
-impl AsyncSemaphoreReleaser<'_> {
-    pub fn disarm(self) {
-        #[cfg(feature = "_rt-tokio")]
-        {
-            self.inner.forget();
-        }
-
-        #[cfg(all(feature = "_rt-async-std", not(feature = "_rt-tokio")))]
-        {
-            let mut this = self;
-            this.inner.disarm();
-        }
-
-        #[cfg(not(any(feature = "_rt-async-std", feature = "_rt-tokio")))]
-        crate::rt::missing_rt(())
-    }
-}