Try to make the class LockUtility RAII complaint

src/gui/clientgui.cpp

@@ -457,9 +457,9 @@ void ClientGui::setupSynthesisPopover() {
     _workaroundManualVisibility = true;
 #endif
 
-    qCInfo(lcClientGui) << "Tray menu workarounds:"
-                        << "noabouttoshow:" << _workaroundNoAboutToShowUpdate << "fakedoubleclick:" << _workaroundFakeDoubleClick
-                        << "showhide:" << _workaroundShowAndHideTray << "manualvisibility:" << _workaroundManualVisibility;
+    qCInfo(lcClientGui) << "Tray menu workarounds:" << "noabouttoshow:" << _workaroundNoAboutToShowUpdate
+                        << "fakedoubleclick:" << _workaroundFakeDoubleClick << "showhide:" << _workaroundShowAndHideTray
+                        << "manualvisibility:" << _workaroundManualVisibility;
 
     connect(&_delayedTrayUpdateTimer, &QTimer::timeout, this, &ClientGui::onUpdateSystray);
     _delayedTrayUpdateTimer.setInterval(2 * 1000);
@@ -761,8 +761,8 @@ void ClientGui::onNewDriveWizard() {
 
 void ClientGui::onShowWindowsUpdateDialog(const VersionInfo &versionInfo) const {
     static std::mutex mutex;
-    if (const std::unique_lock lock(mutex, std::try_to_lock); !lock.owns_lock()) return;
-
+    LockUtility lock(mutex);
+    if (!lock.ownLock()) return;
     if (UpdateDialog dialog(versionInfo); dialog.exec() == QDialog::Accepted) {
         GuiRequests::startInstaller();
     } else if (dialog.skip()) {

src/libcommon/utility/lockutility.h

@@ -28,24 +28,15 @@ namespace KDC {
 
 class LockUtility {
     public:
-        /**
-         * Acquire the lock.
-         * @return Return false if already locked.
-         */
-        [[nodiscard]] bool lock() {
-            const std::scoped_lock lock(_mutex);
-            if (_isLocked) return false;
-            _isLocked = true;
-            return _isLocked;
+        explicit LockUtility(std::mutex &mutex) : _mutex(mutex) { _ownLock = mutex.try_lock(); }
+        ~LockUtility() {
+            if (_ownLock) _mutex.unlock();
         }
-        /**
-         * Release the lock.
-         */
-        void unlock() { _isLocked = false; }
+        [[nodiscard]] bool ownLock() const { return _ownLock; }
 
     private:
-        std::mutex _mutex;
-        bool _isLocked{false};
+        std::mutex &_mutex;
+        bool _ownLock{false};
 };
 
 } // namespace KDC

test/libcommon/utility/testlockutility.cpp

@@ -25,11 +25,16 @@
 namespace KDC {
 
 void TestLockUtility::testLock() {
-    LockUtility lock;
-    CPPUNIT_ASSERT(lock.lock());
-    CPPUNIT_ASSERT(!lock.lock());
-    lock.unlock();
-    CPPUNIT_ASSERT(lock.lock());
+    static std::mutex mutex;
+    {
+        LockUtility lock(mutex);
+        CPPUNIT_ASSERT(lock.ownLock());
+        CPPUNIT_ASSERT(!mutex.try_lock()); // mutex is locked
+        LockUtility lock2(mutex);
+        CPPUNIT_ASSERT(!lock2.ownLock());
+        CPPUNIT_ASSERT(lock.ownLock());
+    }
+    CPPUNIT_ASSERT(mutex.try_lock()); // lock has been released
 }
 
 int randomSleepTime() {
@@ -40,19 +45,19 @@ constexpr unsigned int nbThread = 3;
 constexpr unsigned int nbTest = 5;
 static unsigned int alreadyLockedCounter = 0;
 static unsigned int lockAcquiredCounter = 0;
-static LockUtility lock;
+static std::mutex mutex;
 void testCallback() {
     int i = 0;
     while (i < nbTest) {
+        LockUtility lock(mutex);
         Utility::msleep(randomSleepTime());
-        if (!lock.lock()) {
+        if (!lock.ownLock()) {
             alreadyLockedCounter++;
             Utility::msleep(randomSleepTime());
             continue;
         }
         lockAcquiredCounter++;
         Utility::msleep(10);
-        lock.unlock();
         i++;
     }
 }