Fix setting properties of QJson{Value,Array,Object} type.

Similar to the previous issue, where these types were not properly
converted to QVariant when invoking a method, we manually do the
conversion now to get the desired behavior. The culprit is again
that QJsonValue::toVariant converts an object e.g. to a QVariantMap,
and not to a QVariant containing a QJsonObject.

[ChangeLog] QObject properties of type QJsonValue, QJsonArray or
QJsonObject can now be set via the Qt WebChannel.

Task-number: QTBUG-48198
Change-Id: I5d574b1a5cffd6d6ad9b555f2a3e872b9c3425a7
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

2 files changed, 17 insertions, 8 deletions

diff --git a/src/webchannel/qmetaobjectpublisher.cpp b/src/webchannel/qmetaobjectpublisher.cpp
index e85bc76..0fa4ae2 100644
--- a/src/webchannel/qmetaobjectpublisher.cpp
+++ b/src/webchannel/qmetaobjectpublisher.cpp
@@ -410,6 +410,16 @@ QVariant QMetaObjectPublisher::invokeMethod(QObject *const object, const int met
     return returnValue;
 }
 
+void QMetaObjectPublisher::setProperty(QObject *object, const int propertyIndex, const QJsonValue &value)
+{
+    QMetaProperty property = object->metaObject()->property(propertyIndex);
+    if (!property.isValid()) {
+        qWarning() << "Cannot set unknown property" << propertyIndex << "of object" << object;
+    } else if (!property.write(object, toVariant(value, property.userType()))) {
+        qWarning() << "Could not write value " << value << "to property" << property.name() << "of object" << object;
+    }
+}
+
 void QMetaObjectPublisher::signalEmitted(const QObject *object, const int signalIndex, const QVariantList &arguments)
 {
     if (!webChannel || webChannel->d_func()->transports.isEmpty()) {
@@ -607,14 +617,8 @@ void QMetaObjectPublisher::handleMessage(const QJsonObject &message, QWebChannel
         } else if (type == TypeDisconnectFromSignal) {
             signalHandler.disconnectFrom(object, message.value(KEY_SIGNAL).toInt(-1));
         } else if (type == TypeSetProperty) {
-            const int propertyIdx = message.value(KEY_PROPERTY).toInt(-1);
-            QMetaProperty property = object->metaObject()->property(propertyIdx);
-            if (!property.isValid()) {
-                qWarning() << "Cannot set unknown property" << message.value(KEY_PROPERTY) << "of object" << objectName;
-            } else if (!object->metaObject()->property(propertyIdx).write(object, message.value(KEY_VALUE).toVariant())) {
-                qWarning() << "Could not write value " << message.value(KEY_VALUE)
-                           << "to property" << property.name() << "of object" << objectName;
-            }
+            setProperty(object, message.value(KEY_PROPERTY).toInt(-1),
+                        message.value(KEY_VALUE));
         }
     }
 }
diff --git a/src/webchannel/qmetaobjectpublisher_p.h b/src/webchannel/qmetaobjectpublisher_p.h
index cb3350e..b0ebd84 100644
--- a/src/webchannel/qmetaobjectpublisher_p.h
+++ b/src/webchannel/qmetaobjectpublisher_p.h
@@ -150,6 +150,11 @@ public:
     QVariant invokeMethod(QObject *const object, const int methodIndex, const QJsonArray &args);
 
     /**
+     * Set the value of property @p propertyIndex on @p object to @p value.
+     */
+    void setProperty(QObject *object, const int propertyIndex, const QJsonValue &value);
+
+    /**
      * Callback of the signalHandler which forwards the signal invocation to the webchannel clients.
      */
     void signalEmitted(const QObject *object, const int signalIndex, const QVariantList &arguments);