QFactoryLoader: generalize qLoadPlugin()

- Use perfect forwarding for the additional argument.
- Provide a variadic template version
- Deprecate qLoadPlugin1() — there's no reason for a different name
  — and fix all callers in qtbase.
- Provide non-variadic overloads for up to three additional args
  (QPlatformIntegration rolled its own function because it needs
  three args).

Change-Id: I72fb2dd9a021de704cbf5e4b6ea31c80447fb3b1
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@theqtcompany.com>
Reviewed-by: Lars Knoll <lars.knoll@theqtcompany.com>

1 files changed, 57 insertions, 4 deletions

diff --git a/src/corelib/plugin/qfactoryloader_p.h b/src/corelib/plugin/qfactoryloader_p.h
index ee07084180..a4690c3f03 100644
--- a/src/corelib/plugin/qfactoryloader_p.h
+++ b/src/corelib/plugin/qfactoryloader_p.h
@@ -85,6 +85,23 @@ public:
     QObject *instance(int index) const;
 };
 
+#ifdef Q_COMPILER_VARIADIC_TEMPLATES
+
+template <class PluginInterface, class FactoryInterface, typename ...Args>
+PluginInterface *qLoadPlugin(const QFactoryLoader *loader, const QString &key, Args &&...args)
+{
+    const int index = loader->indexOf(key);
+    if (index != -1) {
+        QObject *factoryObject = loader->instance(index);
+        if (FactoryInterface *factory = qobject_cast<FactoryInterface *>(factoryObject))
+            if (PluginInterface *result = factory->create(key, std::forward<Args>(args)...))
+                return result;
+    }
+    return nullptr;
+}
+
+#else
+
 template <class PluginInterface, class FactoryInterface>
     PluginInterface *qLoadPlugin(const QFactoryLoader *loader, const QString &key)
 {
@@ -98,21 +115,57 @@ template <class PluginInterface, class FactoryInterface>
     return 0;
 }
 
-template <class PluginInterface, class FactoryInterface, class Parameter1>
-PluginInterface *qLoadPlugin1(const QFactoryLoader *loader,
+template <class PluginInterface, class FactoryInterface, class P1>
+PluginInterface *qLoadPlugin(const QFactoryLoader *loader,
                               const QString &key,
-                              const Parameter1 &parameter1)
+                              P1 &&p1)
 {
     const int index = loader->indexOf(key);
     if (index != -1) {
         QObject *factoryObject = loader->instance(index);
         if (FactoryInterface *factory = qobject_cast<FactoryInterface *>(factoryObject))
-            if (PluginInterface *result = factory->create(key, parameter1))
+            if (PluginInterface *result = factory->create(key, std::forward<P1>(p1)))
                 return result;
     }
     return 0;
 }
 
+template <class PluginInterface, class FactoryInterface, class P1, class P2>
+PluginInterface *qLoadPlugin(const QFactoryLoader *loader,
+                              const QString &key,
+                              P1 &&p1, P2 &&p2)
+{
+    const int index = loader->indexOf(key);
+    if (index != -1) {
+        QObject *factoryObject = loader->instance(index);
+        if (FactoryInterface *factory = qobject_cast<FactoryInterface *>(factoryObject))
+            if (PluginInterface *result = factory->create(key, std::forward<P1>(p1), std::forward<P2>(p2)))
+                return result;
+    }
+    return 0;
+}
+
+template <class PluginInterface, class FactoryInterface, class P1, class P2, class P3>
+PluginInterface *qLoadPlugin(const QFactoryLoader *loader,
+                              const QString &key,
+                              P1 &&p1, P2 &&p2, P3 &&p3)
+{
+    const int index = loader->indexOf(key);
+    if (index != -1) {
+        QObject *factoryObject = loader->instance(index);
+        if (FactoryInterface *factory = qobject_cast<FactoryInterface *>(factoryObject))
+            if (PluginInterface *result = factory->create(key, std::forward<P1>(p1), std::forward<P2>(p2), std::forward<P3>(p3)))
+                return result;
+    }
+    return 0;
+}
+
+#endif
+
+template <class PluginInterface, class FactoryInterface, typename Arg>
+Q_DECL_DEPRECATED PluginInterface *qLoadPlugin1(const QFactoryLoader *loader, const QString &key, Arg &&arg)
+{ return qLoadPlugin(loader, key, std::forward<Arg>(arg)); }
+
 QT_END_NAMESPACE
 
 #endif // QT_NO_QOBJECT