Register Qt 4.7 import on-demand, instead of at startup.

This is a slightly less awkward approach (keeps backwards-compatibility) while
speeding up startup for applications that don't use the old import path.

Also prints a warning to let developers know they should migrate their code when
possible. Completely disabling the Qt 4.7 import is still possible by setting
QT_NO_IMPORT_QT47_QML.

This takes around 10-15ms off a very simple "hello world" on my macbook.

As an added bonus, forward-port a similar approach to 4.8's
a26f545d8e25af74fb43d16c9afa79f6e04463e7 and don't register graphical types in a
non-graphical application as someone (very naughtily) apparently forgot to get
it integrated to Qt 5 first.

Change-Id: I7821523750b3ab6770f367788725d0da70c5ec1f
Reviewed-by: Thomas McGuire <thomas.mcguire@kdab.com>
Reviewed-by: Alan Alpert <416365416c@gmail.com>

1 files changed, 7 insertions, 4 deletions

diff --git a/src/declarative/qml/qdeclarativeengine.cpp b/src/declarative/qml/qdeclarativeengine.cpp
index bbf2b6be..b38a4991 100644
--- a/src/declarative/qml/qdeclarativeengine.cpp
+++ b/src/declarative/qml/qdeclarativeengine.cpp
@@ -188,13 +188,16 @@ void QDeclarativeEnginePrivate::defineModule()
     qmlRegisterType<QObject>("QtQuick",1,0,"QtObject");
     qmlRegisterType<QDeclarativeWorkerScript>("QtQuick",1,0,"WorkerScript");
 
+    qmlRegisterType<QDeclarativeBinding>();
+}
+
+void QDeclarativeEnginePrivate::defineModuleCompat()
+{
 #ifndef QT_NO_IMPORT_QT47_QML
     qmlRegisterType<QDeclarativeComponent>("Qt",4,7,"Component");
     qmlRegisterType<QObject>("Qt",4,7,"QtObject");
     qmlRegisterType<QDeclarativeWorkerScript>("Qt",4,7,"WorkerScript");
 #endif
-
-    qmlRegisterType<QDeclarativeBinding>();
 }
 
 /*!
@@ -356,10 +359,10 @@ QDeclarativeEnginePrivate::QDeclarativeEnginePrivate(QDeclarativeEngine *e)
 {
     if (!qt_QmlQtModule_registered) {
         qt_QmlQtModule_registered = true;
-        QDeclarativeItemModule::defineModule();
-        QDeclarativeUtilModule::defineModule();
         QDeclarativeEnginePrivate::defineModule();
+        QDeclarativeItemModule::defineModule();
         QDeclarativeValueTypeFactory::registerValueTypes();
+        QDeclarativeUtilModule::defineModule();
     }
     globalClass = new QDeclarativeGlobalScriptClass(&scriptEngine);
 }