From e9b3146a0e603bf3b5d57172dce751f229b88db3 Mon Sep 17 00:00:00 2001
From: nerix <nerixdev@outlook.de>
Date: Sun, 25 May 2025 16:24:44 +0200
Subject: [PATCH] fix(once-flag): make `flag` atomic (#6237)

---
 CHANGELOG.md          | 1 +
 src/util/OnceFlag.cpp | 7 +++----
 src/util/OnceFlag.hpp | 3 +--
 3 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3eba72da..4ed73aaa 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -53,6 +53,7 @@
 - Dev: Fixed incorrect lua generation of static methods for typescript plugins. (#6190, #6223)
 - Dev: Merged top/bottom and left/right notebook layouts. (#6215)
 - Dev: Refactored `Button` and friends. (#6102)
+- Dev: `OnceFlag`'s internal flag is now atomic. (#6237)
 - Dev: Bumped clang-format requirement to 19. (#6236)
 
 ## 2.5.3
diff --git a/src/util/OnceFlag.cpp b/src/util/OnceFlag.cpp
index cb42ea5a..8ec2f951 100644
--- a/src/util/OnceFlag.cpp
+++ b/src/util/OnceFlag.cpp
@@ -3,13 +3,12 @@
 namespace chatterino {
 
 OnceFlag::OnceFlag() = default;
-OnceFlag::~OnceFlag() = default;
 
 void OnceFlag::set()
 {
     {
         std::unique_lock guard(this->mutex);
-        this->flag = true;
+        this->flag.store(true, std::memory_order::relaxed);
     }
     this->condvar.notify_all();
 }
@@ -18,7 +17,7 @@ bool OnceFlag::waitFor(std::chrono::milliseconds ms)
 {
     std::unique_lock lock(this->mutex);
     return this->condvar.wait_for(lock, ms, [this] {
-        return this->flag;
+        return this->flag.load(std::memory_order::relaxed);
     });
 }
 
@@ -26,7 +25,7 @@ void OnceFlag::wait()
 {
     std::unique_lock lock(this->mutex);
     this->condvar.wait(lock, [this] {
-        return this->flag;
+        return this->flag.load(std::memory_order::relaxed);
     });
 }
 
diff --git a/src/util/OnceFlag.hpp b/src/util/OnceFlag.hpp
index 4060dff2..7d5aeb9f 100644
--- a/src/util/OnceFlag.hpp
+++ b/src/util/OnceFlag.hpp
@@ -14,7 +14,6 @@ class OnceFlag
 {
 public:
     OnceFlag();
-    ~OnceFlag();
 
     /// Set this flag and notify waiters
     void set();
@@ -35,7 +34,7 @@ public:
 private:
     std::mutex mutex;
     std::condition_variable condvar;
-    bool flag = false;
+    std::atomic<bool> flag = false;
 };
 
 }  // namespace chatterino