src: modernize cleanup queue to use c++20

PR-URL: #56063
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>
Reviewed-By: Chengzhong Wu <legendecas@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>

Author: anonrig

src/cleanup_queue-inl.h

@@ -3,6 +3,8 @@
 
 #if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
 
+#include <compare>
+
 #include "cleanup_queue.h"
 #include "util.h"
 
@@ -29,6 +31,18 @@ void CleanupQueue::Remove(Callback cb, void* arg) {
   cleanup_hooks_.erase(search);
 }
 
+constexpr std::strong_ordering CleanupQueue::CleanupHookCallback::operator<=>(
+    const CleanupHookCallback& other) const noexcept {
+  if (insertion_order_counter_ > other.insertion_order_counter_) {
+    return std::strong_ordering::greater;
+  }
+
+  if (insertion_order_counter_ < other.insertion_order_counter_) {
+    return std::strong_ordering::less;
+  }
+  return std::strong_ordering::equivalent;
+}
+
 }  // namespace node
 
 #endif  // defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS

src/cleanup_queue.cc

@@ -1,5 +1,6 @@
 #include "cleanup_queue.h"  // NOLINT(build/include_inline)
 #include <algorithm>
+#include <ranges>
 #include <vector>
 #include "cleanup_queue-inl.h"
 
@@ -8,27 +9,20 @@ namespace node {
 std::vector<CleanupQueue::CleanupHookCallback> CleanupQueue::GetOrdered()
     const {
   // Copy into a vector, since we can't sort an unordered_set in-place.
-  std::vector<CleanupHookCallback> callbacks(cleanup_hooks_.begin(),
-                                             cleanup_hooks_.end());
+  std::vector callbacks(cleanup_hooks_.begin(), cleanup_hooks_.end());
   // We can't erase the copied elements from `cleanup_hooks_` yet, because we
   // need to be able to check whether they were un-scheduled by another hook.
 
-  std::sort(callbacks.begin(),
-            callbacks.end(),
-            [](const CleanupHookCallback& a, const CleanupHookCallback& b) {
-              // Sort in descending order so that the most recently inserted
-              // callbacks are run first.
-              return a.insertion_order_counter_ > b.insertion_order_counter_;
-            });
+  // Sort in descending order so that the most recently inserted callbacks are
+  // run first.
+  std::ranges::sort(callbacks, std::greater());
 
   return callbacks;
 }
 
 void CleanupQueue::Drain() {
-  std::vector<CleanupHookCallback> callbacks = GetOrdered();
-
-  for (const CleanupHookCallback& cb : callbacks) {
-    if (cleanup_hooks_.count(cb) == 0) {
+  for (const CleanupHookCallback& cb : GetOrdered()) {
+    if (!cleanup_hooks_.contains(cb)) {
       // This hook was removed from the `cleanup_hooks_` set during another
       // hook that was run earlier. Nothing to do here.
       continue;

src/cleanup_queue.h

@@ -3,6 +3,7 @@
 
 #if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
 
+#include <compare>
 #include <cstddef>
 #include <cstdint>
 #include <unordered_set>
@@ -41,6 +42,9 @@ class CleanupQueue : public MemoryRetainer {
           arg_(arg),
           insertion_order_counter_(insertion_order_counter) {}
 
+    constexpr std::strong_ordering operator<=>(
+        const CleanupHookCallback& other) const noexcept;
+
     // Only hashes `arg_`, since that is usually enough to identify the hook.
     struct Hash {
       size_t operator()(const CleanupHookCallback& cb) const;