Make QThreadPrivate::createEventDispatcher do exactly what it says

Leaving the logic of starting up the event dispatcher to the call site,
unified both the case of a custom event dispatcher and the default
event dispatcher.

The data argument is left in due to the static nature of the function.

Change-Id: Ia2020e39ccc67cd5a583d4e614dd978b2ec44dba
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

3 files changed, 27 insertions, 23 deletions

diff --git a/src/corelib/thread/qthread_p.h b/src/corelib/thread/qthread_p.h
index baeefd87ff..46294a5fc8 100644
--- a/src/corelib/thread/qthread_p.h
+++ b/src/corelib/thread/qthread_p.h
@@ -195,7 +195,7 @@ public:
 #endif // Q_OS_WIN
     QThreadData *data;
 
-    static void createEventDispatcher(QThreadData *data);
+    static QAbstractEventDispatcher *createEventDispatcher(QThreadData *data);
 
     void ref()
     {
@@ -222,7 +222,7 @@ public:
 
     static void setCurrentThread(QThread*) {}
     static QThread *threadForId(int) { return QThread::currentThread(); }
-    static void createEventDispatcher(QThreadData *data);
+    static QAbstractEventDispatcher *createEventDispatcher(QThreadData *data);
 
     void ref() {}
     void deref() {}
diff --git a/src/corelib/thread/qthread_unix.cpp b/src/corelib/thread/qthread_unix.cpp
index 31292a0598..2c815b870a 100644
--- a/src/corelib/thread/qthread_unix.cpp
+++ b/src/corelib/thread/qthread_unix.cpp
@@ -285,27 +285,26 @@ typedef void*(*QtThreadCallback)(void*);
 
 #endif // QT_NO_THREAD
 
-void QThreadPrivate::createEventDispatcher(QThreadData *data)
+QAbstractEventDispatcher *QThreadPrivate::createEventDispatcher(QThreadData *data)
 {
+    Q_UNUSED(data);
 #if defined(Q_OS_DARWIN)
     bool ok = false;
     int value = qEnvironmentVariableIntValue("QT_EVENT_DISPATCHER_CORE_FOUNDATION", &ok);
     if (ok && value > 0)
-        data->eventDispatcher.storeRelease(new QEventDispatcherCoreFoundation);
+        return new QEventDispatcherCoreFoundation;
     else
-        data->eventDispatcher.storeRelease(new QEventDispatcherUNIX);
+        return new QEventDispatcherUNIX;
 #elif !defined(QT_NO_GLIB)
     if (qEnvironmentVariableIsEmpty("QT_NO_GLIB")
         && qEnvironmentVariableIsEmpty("QT_NO_THREADED_GLIB")
         && QEventDispatcherGlib::versionSupported())
-        data->eventDispatcher.storeRelease(new QEventDispatcherGlib);
+        return new QEventDispatcherGlib;
     else
-        data->eventDispatcher.storeRelease(new QEventDispatcherUNIX);
+        return new QEventDispatcherUNIX;
 #else
-    data->eventDispatcher.storeRelease(new QEventDispatcherUNIX);
+    return new QEventDispatcherUNIX;
 #endif
-
-    data->eventDispatcher.load()->startingUp();
 }
 
 #ifndef QT_NO_THREAD
@@ -352,10 +351,13 @@ void *QThreadPrivate::start(void *arg)
             data->quitNow = thr->d_func()->exited;
         }
 
-        if (data->hasEventDispatcher()) // custom event dispatcher set?
-            data->eventDispatcher.load()->startingUp();
-        else
-            createEventDispatcher(data);
+        QAbstractEventDispatcher *eventDispatcher = data->eventDispatcher.load();
+        if (!eventDispatcher) {
+            eventDispatcher = createEventDispatcher(data);
+            data->eventDispatcher.storeRelease(eventDispatcher);
+        }
+
+        eventDispatcher->startingUp();
 
 #if (defined(Q_OS_LINUX) || defined(Q_OS_MAC) || defined(Q_OS_QNX))
         {
diff --git a/src/corelib/thread/qthread_win.cpp b/src/corelib/thread/qthread_win.cpp
index 136733444c..4459ae87af 100644
--- a/src/corelib/thread/qthread_win.cpp
+++ b/src/corelib/thread/qthread_win.cpp
@@ -331,15 +331,14 @@ void qt_set_thread_name(HANDLE threadId, LPCSTR threadName)
 
 #endif // QT_NO_THREAD
 
-void QThreadPrivate::createEventDispatcher(QThreadData *data)
+QAbstractEventDispatcher *QThreadPrivate::createEventDispatcher(QThreadData *data)
 {
+    Q_UNUSED(data);
 #ifndef Q_OS_WINRT
-    QEventDispatcherWin32 *theEventDispatcher = new QEventDispatcherWin32;
+    return new QEventDispatcherWin32;
 #else
-    QEventDispatcherWinRT *theEventDispatcher = new QEventDispatcherWinRT;
+    return new QEventDispatcherWinRT;
 #endif
-    data->eventDispatcher.storeRelease(theEventDispatcher);
-    theEventDispatcher->startingUp();
 }
 
 #ifndef QT_NO_THREAD
@@ -360,10 +359,13 @@ unsigned int __stdcall QT_ENSURE_STACK_ALIGNED_FOR_SSE QThreadPrivate::start(voi
         data->quitNow = thr->d_func()->exited;
     }
 
-    if (data->hasEventDispatcher()) // custom event dispatcher set?
-        data->eventDispatcher.load()->startingUp();
-    else
-        createEventDispatcher(data);
+    QAbstractEventDispatcher *eventDispatcher = data->eventDispatcher.load();
+    if (!eventDispatcher) {
+        eventDispatcher = createEventDispatcher(data);
+        data->eventDispatcher.storeRelease(eventDispatcher);
+    }
+
+    eventDispatcher->startingUp();
 
 #if !defined(QT_NO_DEBUG) && defined(Q_CC_MSVC) && !defined(Q_OS_WINRT)
     // sets the name of the current thread.