Allow to create a custom event dispatcher for specific QThreads.

QAbstractEventDispatcher() does no longer install itself into the current
thread.  Instead the new methods QThread::setEventDispatcher() and
QCoreApplication::setEventDispatcher() allow to install a custom event
dispatcher into any QThread as long as there is no default event dispatcher
created yet.  That is, before the thread has been started with
QThread::start() or, in case of the main thread, before QCoreApplication has
been instantiated.

Change-Id: I7367e13d8d8aebed5a5651260bb69b8818eb1b90
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>
Reviewed-by: Bradley T. Hughes <bradley.hughes@nokia.com>

1 files changed, 55 insertions, 0 deletions

diff --git a/tests/auto/corelib/kernel/qcoreapplication/tst_qcoreapplication.cpp b/tests/auto/corelib/kernel/qcoreapplication/tst_qcoreapplication.cpp
index 62275f841a..09f31414a6 100644
--- a/tests/auto/corelib/kernel/qcoreapplication/tst_qcoreapplication.cpp
+++ b/tests/auto/corelib/kernel/qcoreapplication/tst_qcoreapplication.cpp
@@ -62,6 +62,7 @@ private slots:
     void reexec();
     void execAfterExit();
     void eventLoopExecAfterExit();
+    void customEventDispatcher();
 };
 
 class EventSpy : public QObject
@@ -586,5 +587,59 @@ void tst_QCoreApplication::eventLoopExecAfterExit()
     QCOMPARE(loop.exec(), 0);
 }
 
+class DummyEventDispatcher : public QAbstractEventDispatcher {
+public:
+    DummyEventDispatcher() : QAbstractEventDispatcher(), visited(false) {}
+    bool processEvents(QEventLoop::ProcessEventsFlags) {
+        visited = true;
+        emit awake();
+        QCoreApplication::sendPostedEvents();
+        return false;
+    }
+    bool hasPendingEvents() {
+        extern uint qGlobalPostedEventsCount(); // from qapplication.cpp
+        return qGlobalPostedEventsCount();
+    }
+    void registerSocketNotifier(QSocketNotifier *) {}
+    void unregisterSocketNotifier(QSocketNotifier *) {}
+    void registerTimer(int , int , QObject *) {}
+    bool unregisterTimer(int ) { return false; }
+    bool unregisterTimers(QObject *) { return false; }
+    QList<TimerInfo> registeredTimers(QObject *) const { return QList<TimerInfo>(); }
+    void wakeUp() {}
+    void interrupt() {}
+    void flush() {}
+
+    bool visited;
+};
+
+void tst_QCoreApplication::customEventDispatcher()
+{
+    // there should be no ED yet
+    QVERIFY(!QCoreApplication::eventDispatcher());
+    DummyEventDispatcher *ed = new DummyEventDispatcher;
+    QCoreApplication::setEventDispatcher(ed);
+    // the new ED should be set
+    QCOMPARE(QCoreApplication::eventDispatcher(), ed);
+    // test the alternative API of QAbstractEventDispatcher
+    QCOMPARE(QAbstractEventDispatcher::instance(), ed);
+    QWeakPointer<DummyEventDispatcher> weak_ed(ed);
+    QVERIFY(!weak_ed.isNull());
+    {
+        int argc = 1;
+        char *arg0 = "tst_qcoreapplication";
+        char *argv[] = { arg0 };
+        QCoreApplication app(argc, argv);
+        // instantiating app should not overwrite the ED
+        QCOMPARE(QCoreApplication::eventDispatcher(), ed);
+        QMetaObject::invokeMethod(&app, "quit", Qt::QueuedConnection);
+        app.exec();
+        // the custom ED has really been used?
+        QVERIFY(ed->visited);
+    }
+    // ED has been deleted?
+    QVERIFY(weak_ed.isNull());
+}
+
 QTEST_APPLESS_MAIN(tst_QCoreApplication)
 #include "tst_qcoreapplication.moc"