Fix event delevery order

Some functions (such as QObject::moveToThread) did not keep
the event ordered by priority.
And because qUpperBound is used to add events, that mean new
events would not be inserted in order.

Task-number: QTBUG19637
Change-Id: I38eb9addb1cdd45b8566e000361ac6e5f1f2c2b8
Reviewed-on: http://codereview.qt.nokia.com/733
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Bradley T. Hughes <bradley.hughes@nokia.com>
Reviewed-by: Olivier Goffart <olivier.goffart@nokia.com>

4 files changed, 26 insertions, 18 deletions

diff --git a/src/corelib/kernel/qcoreapplication.cpp b/src/corelib/kernel/qcoreapplication.cpp
index a8c40c5180..cc1b1812e5 100644
--- a/src/corelib/kernel/qcoreapplication.cpp
+++ b/src/corelib/kernel/qcoreapplication.cpp
@@ -1272,20 +1272,7 @@ void QCoreApplication::postEvent(QObject *receiver, QEvent *event, int priority)
     // delete the event on exceptions to protect against memory leaks till the event is
     // properly owned in the postEventList
     QScopedPointer<QEvent> eventDeleter(event);
-    if (data->postEventList.isEmpty() || data->postEventList.last().priority >= priority) {
-        // optimization: we can simply append if the last event in
-        // the queue has higher or equal priority
-        data->postEventList.append(QPostEvent(receiver, event, priority));
-    } else {
-        // insert event in descending priority order, using upper
-        // bound for a given priority (to ensure proper ordering
-        // of events with the same priority)
-        QPostEventList::iterator begin = data->postEventList.begin()
-                                         + data->postEventList.insertionOffset,
-                                   end = data->postEventList.end();
-        QPostEventList::iterator at = qUpperBound(begin, end, priority);
-        data->postEventList.insert(at, QPostEvent(receiver, event, priority));
-    }
+    data->postEventList.addEvent(QPostEvent(receiver, event, priority));
     eventDeleter.take();
     event->posted = true;
     ++receiver->d_func()->postedEvents;
@@ -1445,7 +1432,7 @@ void QCoreApplicationPrivate::sendPostedEvents(QObject *receiver, int event_type
                 // cannot send deferred delete
                 if (!event_type && !receiver) {
                     // don't lose the event
-                    data->postEventList.append(pe);
+                    data->postEventList.addEvent(pe);
                     const_cast<QPostEvent &>(pe).event = 0;
                 }
                 continue;
diff --git a/src/corelib/kernel/qobject.cpp b/src/corelib/kernel/qobject.cpp
index b88643df5c..88618c3c87 100644
--- a/src/corelib/kernel/qobject.cpp
+++ b/src/corelib/kernel/qobject.cpp
@@ -1482,7 +1482,7 @@ void QObjectPrivate::setThreadData_helper(QThreadData *currentData, QThreadData
             continue;
         if (pe.receiver == q) {
             // move this post event to the targetList
-            targetData->postEventList.append(pe);
+            targetData->postEventList.addEvent(pe);
             const_cast<QPostEvent &>(pe).event = 0;
             ++eventsMoved;
         }
diff --git a/src/corelib/thread/qthread_p.h b/src/corelib/thread/qthread_p.h
index 13df3e6fea..461d93dd50 100644
--- a/src/corelib/thread/qthread_p.h
+++ b/src/corelib/thread/qthread_p.h
@@ -93,6 +93,8 @@ inline bool operator<(const QPostEvent &pe, int priority)
     return priority < pe.priority;
 }
 
+// This class holds the list of posted events.
+//  The list has to be kept sorted by priority
 class QPostEventList : public QList<QPostEvent>
 {
 public:
@@ -109,6 +111,25 @@ public:
     inline QPostEventList()
         : QList<QPostEvent>(), recursion(0), startOffset(0), insertionOffset(0)
     { }
+
+    void addEvent(const QPostEvent &ev) {
+        int priority = ev.priority;
+        if (isEmpty() || last().priority >= priority) {
+            // optimization: we can simply append if the last event in
+            // the queue has higher or equal priority
+            append(ev);
+        } else {
+            // insert event in descending priority order, using upper
+            // bound for a given priority (to ensure proper ordering
+            // of events with the same priority)
+            QPostEventList::iterator at = qUpperBound(begin() + insertionOffset, end(), priority);
+            insert(at, ev);
+        }
+    }
+private:
+    //hides because they do not keep that list sorted. addEvent must be used
+    using QList<QPostEvent>::append;
+    using QList<QPostEvent>::insert;
 };
 
 #ifndef QT_NO_THREAD
diff --git a/src/gui/kernel/qapplication.cpp b/src/gui/kernel/qapplication.cpp
index 38035997fe..361ec6ddec 100644
--- a/src/gui/kernel/qapplication.cpp
+++ b/src/gui/kernel/qapplication.cpp
@@ -1288,8 +1288,8 @@ bool QApplication::compressEvent(QEvent *event, QObject *receiver, QPostEventLis
           || event->type() == QEvent::LanguageChange
           || event->type() == QEvent::UpdateSoftKeys
           || event->type() == QEvent::InputMethod)) {
-        for (int i = 0; i < postedEvents->size(); ++i) {
-            const QPostEvent &cur = postedEvents->at(i);
+        for (QPostEventList::const_iterator it = postedEvents->constBegin(); it != postedEvents->constEnd(); ++it) {
+            const QPostEvent &cur = *it;
             if (cur.receiver != receiver || cur.event == 0 || cur.event->type() != event->type())
                 continue;
             if (cur.event->type() == QEvent::LayoutRequest