Use QHash::tryEmplace

Instead of size != oldSize pattern.

Just some locations I could find using a simple regex lookup.

Task-number: QTBUG-130259
Change-Id: I0ac6a4faf8705ce54cb8dd875ee5524ef13f03dc
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/io/qloggingregistry.cpp

@@ -337,11 +337,9 @@ void QLoggingRegistry::registerCategory(QLoggingCategory *cat, QtMsgType enableF
 {
     const auto locker = qt_scoped_lock(registryMutex);
 
-    const auto oldSize = categories.size();
-    auto &e = categories[cat];
-    if (categories.size() != oldSize) {
+    auto r = categories.tryEmplace(cat, enableForLevel);
+    if (r.inserted) {
         // new entry
-        e = enableForLevel;
         (*categoryFilter)(cat);
     }
 }

src/corelib/kernel/qmetatype.cpp

@@ -1688,12 +1688,8 @@ public:
     bool insertIfNotContains(Key k, const T &f)
     {
         const QWriteLocker locker(&lock);
-        const qsizetype oldSize = map.size();
-        auto &e = map[k];
-        if (map.size() == oldSize) // already present
-            return false;
-        e = f;
-        return true;
+        auto r = map.tryEmplace(k, f);
+        return r.inserted;
     }
 
     const T *function(Key k) const