From 1376c5a617be5c25655d0d7cb63e3beaa5a6e026 Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Wed, 17 Apr 2024 14:20:39 +0200
Subject: Merging upstream version 1.70.0+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 vendor/elsa/src/sync.rs | 26 ++++++++++++++++----------
 1 file changed, 16 insertions(+), 10 deletions(-)

(limited to 'vendor/elsa/src')

diff --git a/vendor/elsa/src/sync.rs b/vendor/elsa/src/sync.rs
index afa4bb7c7..5746989d1 100644
--- a/vendor/elsa/src/sync.rs
+++ b/vendor/elsa/src/sync.rs
@@ -13,7 +13,6 @@ use std::collections::BTreeMap;
 use std::collections::HashMap;
 use std::hash::Hash;
 use std::iter::{FromIterator, IntoIterator};
-use std::mem::MaybeUninit;
 use std::ops::Index;
 
 use std::sync::atomic::AtomicPtr;
@@ -301,9 +300,11 @@ pub struct LockFreeFrozenVec<T: Copy> {
 impl<T: Copy> Drop for LockFreeFrozenVec<T> {
     fn drop(&mut self) {
         let cap = *self.cap.get_mut();
-        let layout = self.layout(cap);
-        unsafe {
-            std::alloc::dealloc((*self.data.get_mut()).cast(), layout);
+        let layout = Self::layout(cap);
+        if cap != 0 {
+            unsafe {
+                std::alloc::dealloc((*self.data.get_mut()).cast(), layout);
+            }
         }
     }
 }
@@ -326,9 +327,7 @@ impl<T: Copy> LockFreeFrozenVec<T> {
 
     pub fn with_capacity(cap: usize) -> Self {
         Self {
-            data: AtomicPtr::new(
-                Box::into_raw(vec![MaybeUninit::<T>::uninit(); cap].into_boxed_slice()).cast(),
-            ),
+            data: AtomicPtr::new(unsafe { std::alloc::alloc(Self::layout(cap)) }.cast()),
             len: AtomicUsize::new(0),
             cap: AtomicUsize::new(cap),
         }
@@ -349,7 +348,7 @@ impl<T: Copy> LockFreeFrozenVec<T> {
         ret
     }
 
-    fn layout(&self, cap: usize) -> Layout {
+    fn layout(cap: usize) -> Layout {
         let num_bytes = std::mem::size_of::<T>() * cap;
         let align = std::mem::align_of::<T>();
         Layout::from_size_align(num_bytes, align).unwrap()
@@ -375,7 +374,7 @@ impl<T: Copy> LockFreeFrozenVec<T> {
             if len >= cap {
                 if cap == 0 {
                     // No memory allocated yet
-                    let layout = self.layout(128);
+                    let layout = Self::layout(128);
                     // SAFETY: `LockFreeFrozenVec` statically rejects zsts
                     unsafe {
                         *ptr = std::alloc::alloc(layout).cast::<T>();
@@ -385,7 +384,7 @@ impl<T: Copy> LockFreeFrozenVec<T> {
                     self.cap.store(128, Ordering::Release);
                 } else {
                     // Out of memory, realloc with double the capacity
-                    let layout = self.layout(cap);
+                    let layout = Self::layout(cap);
                     let new_size = layout.size() * 2;
                     // SAFETY: `LockFreeFrozenVec` statically rejects zsts and the input `ptr` has always been
                     // allocated at the size stated in `cap`.
@@ -459,6 +458,13 @@ fn test_non_lockfree() {
             }
         });
     }
+    // Test dropping empty vecs
+    for _ in [
+        LockFreeFrozenVec::<()>::new(),
+        LockFreeFrozenVec::with_capacity(1),
+        LockFreeFrozenVec::with_capacity(2),
+        LockFreeFrozenVec::with_capacity(1000),
+    ] {}
 }
 
 /// Append-only threadsafe version of `std::collections::BTreeMap` where
-- 
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