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>

1 files changed, 21 insertions, 0 deletions

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