Fix asynchronous method calls on QObjects in different threads

Use QMetaMethod::invoke without a return for void method calls,
which allows making asynchronous method calls onto QObjects in
different affinities than the QWebChannel that's emitting them.

Also adds a unit test called testAsyncObject that intentionally
places a QObject in a different affinity and then tests calls
into it from the QWebChannel's synchronous publisher.

Task-number: QTBUG-47678
Change-Id: I6c35ee54f764c0fc1b0431fb0774aa7e75039abf
Reviewed-by: Dave Andrews <jetdog330@hotmail.com>
Reviewed-by: Milian Wolff <milian.wolff@kdab.com>

2 files changed, 56 insertions, 0 deletions

diff --git a/tests/auto/webchannel/tst_webchannel.cpp b/tests/auto/webchannel/tst_webchannel.cpp
index 5ee26ec..55723ea 100644
--- a/tests/auto/webchannel/tst_webchannel.cpp
+++ b/tests/auto/webchannel/tst_webchannel.cpp
@@ -370,6 +370,12 @@ void TestWebChannel::testInfoForObject()
         }
         {
             QJsonArray method;
+            method.append(QStringLiteral("setProp"));
+            method.append(obj.metaObject()->indexOfMethod("setProp(QString)"));
+            expected.append(method);
+        }
+        {
+            QJsonArray method;
             method.append(QStringLiteral("method1"));
             method.append(obj.metaObject()->indexOfMethod("method1()"));
             expected.append(method);
@@ -478,6 +484,19 @@ void TestWebChannel::testInfoForObject()
             property.append(QJsonValue::fromVariant(QVariant::fromValue(obj.returnedObject())));
             expected.append(property);
         }
+        {
+            QJsonArray property;
+            property.append(obj.metaObject()->indexOfProperty("prop"));
+            property.append(QStringLiteral("prop"));
+            {
+                QJsonArray signal;
+                signal.append(1);
+                signal.append(obj.metaObject()->indexOfMethod("propChanged(QString)"));
+                property.append(signal);
+            }
+            property.append(QJsonValue::fromVariant(QVariant::fromValue(obj.prop())));
+            expected.append(property);
+        }
         QCOMPARE(info["properties"].toArray(), expected);
     }
 }
@@ -699,6 +718,32 @@ void TestWebChannel::testInfiniteRecursion()
     QJsonObject objectInfo = channel.d_func()->publisher->wrapResult(QVariant::fromValue(&obj), m_dummyTransport).toObject();
 }
 
+void TestWebChannel::testAsyncObject()
+{
+    QWebChannel channel;
+    channel.connectTo(m_dummyTransport);
+
+    QThread thread;
+    thread.start();
+
+    TestObject obj;
+    obj.moveToThread(&thread);
+
+    QJsonArray args;
+    args.append(QJsonValue("message"));
+
+    int method = obj.metaObject()->indexOfMethod("setProp(QString)");
+    QVERIFY(method != -1);
+
+    QSignalSpy spy(&obj, &TestObject::propChanged);
+    channel.d_func()->publisher->invokeMethod(&obj, method, args);
+    QVERIFY(spy.wait());
+    QCOMPARE(spy.at(0).at(0).toString(), args.at(0).toString());
+
+    thread.quit();
+    thread.wait();
+}
+
 static QHash<QString, QObject*> createObjects(QObject *parent)
 {
     const int num = 100;
diff --git a/tests/auto/webchannel/tst_webchannel.h b/tests/auto/webchannel/tst_webchannel.h
index 0f5cf1c..70a368c 100644
--- a/tests/auto/webchannel/tst_webchannel.h
+++ b/tests/auto/webchannel/tst_webchannel.h
@@ -74,6 +74,7 @@ class TestObject : public QObject
     Q_PROPERTY(QString bar READ bar NOTIFY theBarHasChanged)
     Q_PROPERTY(QObject * objectProperty READ objectProperty WRITE setObjectProperty NOTIFY objectPropertyChanged)
     Q_PROPERTY(TestObject * returnedObject READ returnedObject WRITE setReturnedObject NOTIFY returnedObjectChanged)
+    Q_PROPERTY(QString prop READ prop WRITE setProp NOTIFY propChanged)
 
 public:
     explicit TestObject(QObject *parent = 0)
@@ -101,6 +102,11 @@ public:
         return mReturnedObject;
     }
 
+    QString prop() const
+    {
+        return mProp;
+    }
+
     Q_INVOKABLE void method1() {}
 
 protected:
@@ -116,6 +122,7 @@ signals:
     void theBarHasChanged();
     void objectPropertyChanged();
     void returnedObjectChanged();
+    void propChanged(const QString&);
 
 public slots:
     void slot1() {}
@@ -133,6 +140,8 @@ public slots:
         emit objectPropertyChanged();
     }
 
+    void setProp(const QString&prop) {emit propChanged(mProp=prop);}
+
 protected slots:
     void slot3() {}
 
@@ -142,6 +151,7 @@ private slots:
 public:
     QObject *mObjectProperty;
     TestObject *mReturnedObject;
+    QString mProp;
 };
 
 class BenchObject : public QObject
@@ -286,6 +296,7 @@ private slots:
     void testRemoveUnusedTransports();
     void testPassWrappedObjectBack();
     void testInfiniteRecursion();
+    void testAsyncObject();
 
     void benchClassInfo();
     void benchInitializeClients();