add exceptions

src/app/browser/main/tab.cpp

@@ -33,14 +33,14 @@ Glib::ustring Tab::get_page_title(
         PAGE_NUMBER
     );
 
-    if (pageWidget != nullptr)
+    if (pageWidget == nullptr)
     {
+        throw _("Tab page not found!");
+    }
+
     auto tabPage = (tab::Page *) pageWidget;
 
     return tabPage->get_title();
-    }
-
-    return ""; // @TODO
 };
 
 Glib::ustring Tab::get_page_subtitle(
@@ -50,14 +50,14 @@ Glib::ustring Tab::get_page_subtitle(
         PAGE_NUMBER
     );
 
-    if (pageWidget != nullptr)
+    if (pageWidget == nullptr)
     {
+        throw _("Tab page not found!");
+    }
+
     auto tabPage = (tab::Page *) pageWidget;
 
     return tabPage->get_subtitle();
-    }
-
-    return ""; // @TODO
 };
 
 // Actions