QJSEngine: Optimize conversion from QObject* to QString

This is commonly done for logging. With this in place we can have the
code generator use coerceType() for such constructs.

[ChangeLog][QML][Important Behavior Changes] You can implement custom
toString() methods for your QML objects in JavaScript or in C++. Those
methods don't actually have to return a string. Previously, whatever
return value the method generated was forwarded as-is. Now it is coerced
to a string.

Change-Id: I4a9721a6948be0c24a36b31d453a74bd747db729
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Sami Shalayel <sami.shalayel@qt.io>

1 files changed, 6 insertions, 0 deletions

diff --git a/src/qml/jsapi/qjsengine.cpp b/src/qml/jsapi/qjsengine.cpp
index c15b5c1ccd..8b0b650c1f 100644
--- a/src/qml/jsapi/qjsengine.cpp
+++ b/src/qml/jsapi/qjsengine.cpp
@@ -920,6 +920,12 @@ bool QJSEngine::convertMetaType(QMetaType fromType, const void *from, QMetaType
     return QV4::ExecutionEngine::metaTypeFromJS(handle()->fromData(fromType, from), toType, to);
 }
 
+QString QJSEngine::convertQObjectToString(QObject *object)
+{
+    return QV4::QObjectWrapper::objectToString(
+                handle(), object ? object->metaObject() : nullptr, object);
+}
+
 /*! \fn template <typename T> QJSValue QJSEngine::toScriptValue(const T &value)
 
     Creates a QJSValue with the given \a value.