QGuiApplication: drop mutex before emitting fontChanged()

Emitting a signal executes an unknowable amount of code. We shouldn't hold a mutex while doing so. E.g., if the signal emission causes another call to QGuiApplication::setFont(), the old code would deadlock, since applicationFontMutex is not recursive. Fix by taking a copy of the application font under mutex protection, then dropping the lock for the emission of the signal. Change-Id: Ib2569b3a08af6ef5f38459a19f74cb0db27b7772 Reviewed-by: Volker Hilsheimer <[email protected]> Reviewed-by: Lars Knoll <[email protected]>
zhangzhuo520 · Aug 23, 2019 · 96ff6e8 · 96ff6e8
1 parent b1db1dd
commit 96ff6e8
Showing 1 changed file with 5 additions and 2 deletions.
diff --git a/src/gui/kernel/qguiapplication.cpp b/src/gui/kernel/qguiapplication.cpp
@@ -3284,8 +3284,11 @@ void QGuiApplication::setFont(const QFont &font)
         *QGuiApplicationPrivate::app_font = font;
     applicationResourceFlags |= ApplicationFontExplicitlySet;
 
-    if (emitChange && qGuiApp)
-        emit qGuiApp->fontChanged(*QGuiApplicationPrivate::app_font);
+    if (emitChange && qGuiApp) {
+        auto font = *QGuiApplicationPrivate::app_font;
+        locker.unlock();
+        emit qGuiApp->fontChanged(font);
+    }
 }
 
 /*!