Fix handle leak in symbian QTimer implementation

The timer handle was only being closed when a timer was cancelled,
which resulted in a leak for one shot timers that have completed normally.

Instead the timer is now closed in a destructor (closing null handles is
safe, so it doesn't matter if the handle was never created - e.g. in the
case of a zero timer)
Also added a handle check before creating a timer to prevent a leak in
case the start function is called twice in the backend.

Task-number: QTBUG-16380
Reviewed-by: mread
(cherry picked from commit 2b1b617664bfc78f6e95e53dc0f9749bd1f2d27a)

1 files changed, 4 insertions, 2 deletions

diff --git a/src/corelib/kernel/qeventdispatcher_symbian.cpp b/src/corelib/kernel/qeventdispatcher_symbian.cpp
index bb9bd01..99c4087 100644
--- a/src/corelib/kernel/qeventdispatcher_symbian.cpp
+++ b/src/corelib/kernel/qeventdispatcher_symbian.cpp
@@ -217,13 +217,13 @@ QTimerActiveObject::QTimerActiveObject(QEventDispatcherSymbian *dispatcher, Symb
 QTimerActiveObject::~QTimerActiveObject()
 {
     Cancel();
+    m_rTimer.Close(); //close of null handle is safe
 }
 
 void QTimerActiveObject::DoCancel()
 {
     if (m_timerInfo->interval > 0) {
         m_rTimer.Cancel();
-        m_rTimer.Close();
     } else {
         if (iStatus.Int() == KRequestPending) {
             TRequestStatus *status = &iStatus;
@@ -302,7 +302,9 @@ void QTimerActiveObject::Start()
     CActiveScheduler::Add(this);
     m_timerInfo->msLeft = m_timerInfo->interval;
     if (m_timerInfo->interval > 0) {
-        m_rTimer.CreateLocal();
+        if (!m_rTimer.Handle()) {
+            qt_symbian_throwIfError(m_rTimer.CreateLocal());
+        }
         StartTimer();
     } else {
         iStatus = KRequestPending;