Use MaybeUninit::assume_init_{drop,read}

crossbeam-rs · Dec 23, 2023 · 89bdcb4 · 89bdcb4
1 parent 9a865c7
commit 89bdcb4
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Showing 7 changed files with 12 additions and 22 deletions.
diff --git a/crossbeam-channel/src/flavors/array.rs b/crossbeam-channel/src/flavors/array.rs
@@ -549,8 +549,7 @@ impl<T> Drop for Channel<T> {
             unsafe {
                 debug_assert!(index < self.buffer.len());
                 let slot = self.buffer.get_unchecked_mut(index);
-                let msg = &mut *slot.msg.get();
-                msg.as_mut_ptr().drop_in_place();
+                (*slot.msg.get()).assume_init_drop();
             }
         }
     }

diff --git a/crossbeam-channel/src/flavors/list.rs b/crossbeam-channel/src/flavors/list.rs
@@ -604,8 +604,7 @@ impl<T> Channel<T> {
                     // Drop the message in the slot.
                     let slot = (*block).slots.get_unchecked(offset);
                     slot.wait_write();
-                    let p = &mut *slot.msg.get();
-                    p.as_mut_ptr().drop_in_place();
+                    (*slot.msg.get()).assume_init_drop();
                 } else {
                     (*block).wait_next();
                     // Deallocate the block and move to the next one.
@@ -663,8 +662,7 @@ impl<T> Drop for Channel<T> {
                 if offset < BLOCK_CAP {
                     // Drop the message in the slot.
                     let slot = (*block).slots.get_unchecked(offset);
-                    let p = &mut *slot.msg.get();
-                    p.as_mut_ptr().drop_in_place();
+                    (*slot.msg.get()).assume_init_drop();
                 } else {
                     // Deallocate the block and move to the next one.
                     let next = *(*block).next.get_mut();

diff --git a/crossbeam-deque/src/deque.rs b/crossbeam-deque/src/deque.rs
@@ -1986,8 +1986,7 @@ impl<T> Drop for Injector<T> {
                 if offset < BLOCK_CAP {
                     // Drop the task in the slot.
                     let slot = (*block).slots.get_unchecked(offset);
-                    let p = &mut *slot.task.get();
-                    p.as_mut_ptr().drop_in_place();
+                    (*slot.task.get()).assume_init_drop();
                 } else {
                     // Deallocate the block and move to the next one.
                     let next = *(*block).next.get_mut();

diff --git a/crossbeam-epoch/src/sync/queue.rs b/crossbeam-epoch/src/sync/queue.rs
@@ -132,8 +132,7 @@ impl<T> Queue<T> {
                                 .compare_exchange(tail, next, Release, Relaxed, guard);
                         }
                         guard.defer_destroy(head);
-                        // TODO: Replace with MaybeUninit::read when api is stable
-                        Some(n.data.as_ptr().read())
+                        Some(n.data.assume_init_read())
                     })
                     .map_err(|_| ())
             },
@@ -165,7 +164,7 @@ impl<T> Queue<T> {
                                 .compare_exchange(tail, next, Release, Relaxed, guard);
                         }
                         guard.defer_destroy(head);
-                        Some(n.data.as_ptr().read())
+                        Some(n.data.assume_init_read())
                     })
                     .map_err(|_| ())
             },

diff --git a/crossbeam-queue/src/array_queue.rs b/crossbeam-queue/src/array_queue.rs
@@ -476,8 +476,7 @@ impl<T> Drop for ArrayQueue<T> {
             unsafe {
                 debug_assert!(index < self.buffer.len());
                 let slot = self.buffer.get_unchecked_mut(index);
-                let value = &mut *slot.value.get();
-                value.as_mut_ptr().drop_in_place();
+                (*slot.value.get()).assume_init_drop();
             }
         }
     }

diff --git a/crossbeam-queue/src/seg_queue.rs b/crossbeam-queue/src/seg_queue.rs
@@ -459,8 +459,7 @@ impl<T> Drop for SegQueue<T> {
                 if offset < BLOCK_CAP {
                     // Drop the value in the slot.
                     let slot = (*block).slots.get_unchecked(offset);
-                    let p = &mut *slot.value.get();
-                    p.as_mut_ptr().drop_in_place();
+                    (*slot.value.get()).assume_init_drop();
                 } else {
                     // Deallocate the block and move to the next one.
                     let next = *(*block).next.get_mut();
@@ -525,8 +524,7 @@ impl<T> Iterator for IntoIter<T> {
             // and this is a non-empty queue.
             let item = unsafe {
                 let slot = (*block).slots.get_unchecked(offset);
-                let p = &mut *slot.value.get();
-                p.as_mut_ptr().read()
+                slot.value.get().read().assume_init()
             };
             if offset + 1 == BLOCK_CAP {
                 // Deallocate the block and move to the next one.

diff --git a/crossbeam-utils/src/sync/once_lock.rs b/crossbeam-utils/src/sync/once_lock.rs
@@ -61,13 +61,11 @@ impl<T> OnceLock<T> {
     where
         F: FnOnce() -> T,
     {
-        let slot = self.value.get().cast::<T>();
+        let slot = self.value.get();
 
         self.once.call_once(|| {
             let value = f();
-            unsafe {
-                slot.write(value);
-            }
+            unsafe { slot.write(MaybeUninit::new(value)) }
         });
     }
 
@@ -84,7 +82,7 @@ impl<T> Drop for OnceLock<T> {
     fn drop(&mut self) {
         if self.once.is_completed() {
             // SAFETY: The inner value has been initialized
-            unsafe { self.value.get().cast::<T>().drop_in_place() };
+            unsafe { (*self.value.get()).assume_init_drop() };
         }
     }
 }