Unwrap QJSValue from QVariant in QV8Engine::fromVariant

When QML tries to unwrap real value from a QVariant and
the value is a QJSValue instance, then no conversion is needed,
QJSValue already contains a v8 handle.

This patch, for example, solves a problem of emitting QJSValue
instance in a signal that has QVariant as an argument. The QJSValue
can be unwrapped and used as a normal JS value in a connected slot.
This feature may be used also in a plugin model that stores QJSValues
internally. Then the model in data() function can return a QJSValue
which would be understood by QML.

Change-Id: I1d5ede40ce2637123b09839fd848b27ad3af3dda
Reviewed-on: http://codereview.qt-project.org/4451
Reviewed-by: Kent Hansen <kent.hansen@nokia.com>
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/src/declarative/qml/v8/qv8engine.cpp b/src/declarative/qml/v8/qv8engine.cpp
index c10f048a20..7be74f8711 100644
--- a/src/declarative/qml/v8/qv8engine.cpp
+++ b/src/declarative/qml/v8/qv8engine.cpp
@@ -341,6 +341,11 @@ v8::Handle<v8::Value> QV8Engine::fromVariant(const QVariant &variant)
             } else {
                 return v8::Null();
             }
+        } else if (type == qMetaTypeId<QJSValue>()) {
+            const QJSValue *value = reinterpret_cast<const QJSValue *>(ptr);
+            QJSValuePrivate *valuep = QJSValuePrivate::get(*value);
+            if (valuep->assignEngine(this))
+                return v8::Local<v8::Value>::New(*valuep);
         } else if (type == qMetaTypeId<QList<QObject *> >()) {
             // XXX Can this be made more by using Array as a prototype and implementing
             // directly against QList<QObject*>?
@@ -358,7 +363,6 @@ v8::Handle<v8::Value> QV8Engine::fromVariant(const QVariant &variant)
     }
 
     // XXX TODO: To be compatible, we still need to handle:
-    //    + QJSValue
     //    + QObjectList
     //    + QList<int>