Surviving out of memory in Qt Quick app

The QtQuickPlayground app contains a version of samegame which allow
the user to edit the code. By setting the ball size to 8, the app can
run out of memory. This leaves it in a pretty bad state. But apps
on Symbian shouldn't crash due to OOM and should allow some operation.

This change fixes the immediate OOM crashes in declarative, gui and
corelib. It shows warning dialogs which explain what has gone wrong and
leaves the app in a state that can be exited cleanly
from the Symbian task list.

Task-number: QT-5319
Reviewed-by: Shane Kearns
Reviewed-by: Gareth Stockwell
Reviewed-by: Martin Jones

10 files changed, 253 insertions, 194 deletions

diff --git a/src/corelib/global/qglobal.cpp b/src/corelib/global/qglobal.cpp
index 84d68e5..3675fc7 100644
--- a/src/corelib/global/qglobal.cpp
+++ b/src/corelib/global/qglobal.cpp
@@ -2207,16 +2207,13 @@ void qt_message_output(QtMsgType msgType, const char *buf)
         OutputDebugString(reinterpret_cast<const wchar_t *> (fstr.utf16()));
 #elif defined(Q_OS_SYMBIAN)
         // RDebug::Print has a cap of 256 characters so break it up
-        _LIT(format, "[Qt Message] %S");
-        const int maxBlockSize = 256 - ((const TDesC &)format).Length();
+        char format[] = "[Qt Message] %S";
+        const int maxBlockSize = 256 - sizeof(format);
         const TPtrC8 ptr(reinterpret_cast<const TUint8*>(buf));
-        HBufC* hbuffer = HBufC::New(qMin(maxBlockSize, ptr.Length()));
-        Q_CHECK_PTR(hbuffer);
-        for (int i = 0; i < ptr.Length(); i += hbuffer->Length()) {
-            hbuffer->Des().Copy(ptr.Mid(i, qMin(maxBlockSize, ptr.Length()-i)));
-            RDebug::Print(format, hbuffer);
+        for (int i = 0; i < ptr.Length(); i += maxBlockSize) {
+            TPtrC8 part(ptr.Mid(i, qMin(maxBlockSize, ptr.Length()-i)));
+            RDebug::Printf(format, &part);
         }
-        delete hbuffer;
 #else
         fprintf(stderr, "%s\n", buf);
         fflush(stderr);
diff --git a/src/corelib/kernel/qeventdispatcher_symbian.cpp b/src/corelib/kernel/qeventdispatcher_symbian.cpp
index ea466f5..da6f021 100644
--- a/src/corelib/kernel/qeventdispatcher_symbian.cpp
+++ b/src/corelib/kernel/qeventdispatcher_symbian.cpp
@@ -749,7 +749,7 @@ public:
         ObjectRun,
         ObjectDelayed
     };
-    static RunResult RunMarkedIfReady(TInt &runPriority, TInt minimumPriority);
+    static RunResult RunMarkedIfReady(TInt &runPriority, TInt minimumPriority, QEventDispatcherSymbian *dispatcher);
     static bool UseRRActiveScheduler();
 
 private:
@@ -808,7 +808,7 @@ void QtRRActiveScheduler::MarkReadyToRun()
     }
 }
 
-QtRRActiveScheduler::RunResult QtRRActiveScheduler::RunMarkedIfReady(TInt &runPriority, TInt minimumPriority)
+QtRRActiveScheduler::RunResult QtRRActiveScheduler::RunMarkedIfReady(TInt &runPriority, TInt minimumPriority, QEventDispatcherSymbian *dispatcher)
 {
     RunResult result = NothingFound;
     TInt error=KErrNone;
@@ -824,12 +824,12 @@ QtRRActiveScheduler::RunResult QtRRActiveScheduler::RunMarkedIfReady(TInt &runPr
                     runPriority = active->Priority();
                     dataAccess->iStatus.iFlags&=~TRequestStatusAccess::ERequestActiveFlags;
                     int vptr = *(int*)active;       // vptr can be used to identify type when debugging leaves
-                    TRAP(error, active->RunL());
+                    TRAP(error, QT_TRYCATCH_ERROR(error, active->RunL()));
                     if (error!=KErrNone)
                         error=active->RunError(error);
                     if (error) {
                         qWarning("Active object (ptr=0x%08x, vptr=0x%08x) leave: %i\n", active, vptr, error);
-                        pS->Error(error);
+                        dispatcher->activeObjectError(error);
                     }
                     return ObjectRun;
                 }
@@ -966,13 +966,15 @@ QEventDispatcherSymbian::QEventDispatcherSymbian(QObject *parent)
       m_wakeUpDone(0),
       m_iterationCount(0),
       m_insideTimerEvent(false),
-      m_noSocketEvents(false)
+      m_noSocketEvents(false),
+      m_oomErrorCount(0)
 {
 #ifdef QT_SYMBIAN_PRIORITY_DROP
     m_delay = baseDelay;
     m_avgEventTime = 0;
     idleDetectorThread();
 #endif
+    m_oomErrorTimer.start();
 }
 
 QEventDispatcherSymbian::~QEventDispatcherSymbian()
@@ -1098,7 +1100,7 @@ bool QEventDispatcherSymbian::processEvents ( QEventLoop::ProcessEventsFlags fla
                 // Standard or above priority AOs are scheduled round robin.
                 // Lower priority AOs can only run if nothing higher priority has run.
                 int runPriority = minPriority;
-                handledSymbianEvent = QtRRActiveScheduler::RunMarkedIfReady(runPriority, minPriority);
+                handledSymbianEvent = QtRRActiveScheduler::RunMarkedIfReady(runPriority, minPriority, this);
                 minPriority = qMin(runPriority, int(CActive::EPriorityStandard));
             } else {
                 TInt error;
@@ -1396,6 +1398,19 @@ QList<QEventDispatcherSymbian::TimerInfo> QEventDispatcherSymbian::registeredTim
     return list;
 }
 
+void QEventDispatcherSymbian::activeObjectError(int error)
+{
+    if (error == KErrNoMemory) {
+        // limit the number of reported out of memory errors, as the disappearance of the warning
+        // dialog can trigger further OOM errors causing a loop.
+        if (m_oomErrorTimer.restart() > 60000)  // 1 minute
+            m_oomErrorCount = 0;
+        if (m_oomErrorCount++ >= 5)
+            return;
+    }
+    CActiveScheduler::Current()->Error(error);
+}
+
 /*
  * This active scheduler class implements a simple report and continue policy, for Symbian OS leaves
  * or exceptions from Qt that fall back to the scheduler.
diff --git a/src/corelib/kernel/qeventdispatcher_symbian_p.h b/src/corelib/kernel/qeventdispatcher_symbian_p.h
index 01f5ab1..869fe31 100644
--- a/src/corelib/kernel/qeventdispatcher_symbian_p.h
+++ b/src/corelib/kernel/qeventdispatcher_symbian_p.h
@@ -264,6 +264,8 @@ public:
     static void RequestComplete(TRequestStatus *&status, TInt reason);
     static void RequestComplete(RThread &threadHandle, TRequestStatus *&status, TInt reason);
 
+    void activeObjectError(int error);
+
 private:
     bool sendPostedEvents();
     bool sendDeferredSocketEvents();
@@ -294,6 +296,8 @@ private:
     int m_delay;
     int m_avgEventTime;
     QElapsedTimer m_lastIdleRequestTimer;
+    int m_oomErrorCount;
+    QElapsedTimer m_oomErrorTimer;
 };
 
 #ifdef QT_DEBUG
diff --git a/src/declarative/qml/qdeclarativecomponent.cpp b/src/declarative/qml/qdeclarativecomponent.cpp
index f423f50..0d892a2 100644
--- a/src/declarative/qml/qdeclarativecomponent.cpp
+++ b/src/declarative/qml/qdeclarativecomponent.cpp
@@ -936,50 +936,37 @@ void QDeclarativeComponentPrivate::beginDeferred(QDeclarativeEnginePrivate *engi
 void QDeclarativeComponentPrivate::complete(QDeclarativeEnginePrivate *enginePriv, ConstructionState *state)
 {
     if (state->completePending) {
-
-        for (int ii = 0; ii < state->bindValues.count(); ++ii) {
-            QDeclarativeEnginePrivate::SimpleList<QDeclarativeAbstractBinding> bv = 
-                state->bindValues.at(ii);
-            for (int jj = 0; jj < bv.count; ++jj) {
-                if(bv.at(jj)) {
-                    // XXX akennedy
-                    bv.at(jj)->m_mePtr = 0;
-                    bv.at(jj)->setEnabled(true, QDeclarativePropertyPrivate::BypassInterceptor | 
-                                                QDeclarativePropertyPrivate::DontRemoveBinding);
+        QT_TRY {
+            for (int ii = 0; ii < state->bindValues.count(); ++ii) {
+                QDeclarativeEnginePrivate::SimpleList<QDeclarativeAbstractBinding> bv = 
+                    state->bindValues.at(ii);
+                for (int jj = 0; jj < bv.count; ++jj) {
+                    if(bv.at(jj)) {
+                        // XXX akennedy
+                        bv.at(jj)->m_mePtr = 0;
+                        bv.at(jj)->setEnabled(true, QDeclarativePropertyPrivate::BypassInterceptor | 
+                                                    QDeclarativePropertyPrivate::DontRemoveBinding);
+                    }
                 }
+                QDeclarativeEnginePrivate::clear(bv);
             }
-            QDeclarativeEnginePrivate::clear(bv);
-        }
 
-        for (int ii = 0; ii < state->parserStatus.count(); ++ii) {
-            QDeclarativeEnginePrivate::SimpleList<QDeclarativeParserStatus> ps = 
-                state->parserStatus.at(ii);
+            for (int ii = 0; ii < state->parserStatus.count(); ++ii) {
+                QDeclarativeEnginePrivate::SimpleList<QDeclarativeParserStatus> ps = 
+                    state->parserStatus.at(ii);
 
-            for (int jj = ps.count - 1; jj >= 0; --jj) {
-                QDeclarativeParserStatus *status = ps.at(jj);
-                if (status && status->d) {
-                    status->d = 0;
-                    status->componentComplete();
+                for (int jj = ps.count - 1; jj >= 0; --jj) {
+                    QDeclarativeParserStatus *status = ps.at(jj);
+                    if (status && status->d) {
+                        status->d = 0;
+                        status->componentComplete();
+                    }
                 }
+                QDeclarativeEnginePrivate::clear(ps);
             }
-            QDeclarativeEnginePrivate::clear(ps);
-        }
-
-        for (int ii = 0; ii < state->finalizedParserStatus.count(); ++ii) {
-            QPair<QDeclarativeGuard<QObject>, int> status = state->finalizedParserStatus.at(ii);
-            QObject *obj = status.first;
-            if (obj) {
-                void *args[] = { 0 };
-                QMetaObject::metacall(obj, QMetaObject::InvokeMetaMethod,
-                                      status.second, args);
-            }
-        }
 
-        //componentComplete() can register additional finalization objects
-        //that are then never handled. Handle them manually here.
-        if (1 == enginePriv->inProgressCreations) {
-            for (int ii = 0; ii < enginePriv->finalizedParserStatus.count(); ++ii) {
-                QPair<QDeclarativeGuard<QObject>, int> status = enginePriv->finalizedParserStatus.at(ii);
+            for (int ii = 0; ii < state->finalizedParserStatus.count(); ++ii) {
+                QPair<QDeclarativeGuard<QObject>, int> status = state->finalizedParserStatus.at(ii);
                 QObject *obj = status.first;
                 if (obj) {
                     void *args[] = { 0 };
@@ -987,17 +974,38 @@ void QDeclarativeComponentPrivate::complete(QDeclarativeEnginePrivate *enginePri
                                           status.second, args);
                 }
             }
-            enginePriv->finalizedParserStatus.clear();
-        }
 
-        while (state->componentAttached) {
-            QDeclarativeComponentAttached *a = state->componentAttached;
-            a->rem();
-            QDeclarativeData *d = QDeclarativeData::get(a->parent());
-            Q_ASSERT(d);
-            Q_ASSERT(d->context);
-            a->add(&d->context->componentAttached);
-            emit a->completed();
+            //componentComplete() can register additional finalization objects
+            //that are then never handled. Handle them manually here.
+            if (1 == enginePriv->inProgressCreations) {
+                for (int ii = 0; ii < enginePriv->finalizedParserStatus.count(); ++ii) {
+                    QPair<QDeclarativeGuard<QObject>, int> status = enginePriv->finalizedParserStatus.at(ii);
+                    QObject *obj = status.first;
+                    if (obj) {
+                        void *args[] = { 0 };
+                        QMetaObject::metacall(obj, QMetaObject::InvokeMetaMethod,
+                                              status.second, args);
+                    }
+                }
+                enginePriv->finalizedParserStatus.clear();
+            }
+
+            while (state->componentAttached) {
+                QDeclarativeComponentAttached *a = state->componentAttached;
+                a->rem();
+                QDeclarativeData *d = QDeclarativeData::get(a->parent());
+                Q_ASSERT(d);
+                Q_ASSERT(d->context);
+                a->add(&d->context->componentAttached);
+                emit a->completed();
+            }
+        } QT_CATCH(const std::exception&) {
+            state->bindValues.clear();
+            state->parserStatus.clear();
+            state->finalizedParserStatus.clear();
+            state->completePending = false;
+            enginePriv->inProgressCreations--;
+            QT_RETHROW;
         }
 
         state->bindValues.clear();
diff --git a/src/declarative/qml/qdeclarativeengine.cpp b/src/declarative/qml/qdeclarativeengine.cpp
index 1417b78..89a9809 100644
--- a/src/declarative/qml/qdeclarativeengine.cpp
+++ b/src/declarative/qml/qdeclarativeengine.cpp
@@ -1202,8 +1202,8 @@ void QDeclarativeData::setBindingBit(QObject *obj, int bit)
         int arraySize = (props + 31) / 32;
         int oldArraySize = bindingBitsSize / 32;
 
-        bindingBits = (quint32 *)realloc(bindingBits,
-                                         arraySize * sizeof(quint32));
+        bindingBits = (quint32 *)q_check_ptr(realloc(bindingBits,
+                                         arraySize * sizeof(quint32)));
 
         memset(bindingBits + oldArraySize,
                0x00,
diff --git a/src/declarative/qml/qpodvector_p.h b/src/declarative/qml/qpodvector_p.h
index 7b50463..a055d17 100644
--- a/src/declarative/qml/qpodvector_p.h
+++ b/src/declarative/qml/qpodvector_p.h
@@ -89,7 +89,7 @@ public:
     void insert(int idx, const T &v) {
         if (m_count == m_capacity) {
             m_capacity += Increment;
-            m_data = (T *)realloc(m_data, m_capacity * sizeof(T));
+            m_data = (T *)q_check_ptr(realloc(m_data, m_capacity * sizeof(T)));
         }
         int moveCount = m_count - idx;
         if (moveCount)
@@ -101,7 +101,7 @@ public:
     void reserve(int count) {
         if (count >= m_capacity) {
             m_capacity = (count + (Increment-1)) & (0xFFFFFFFF - Increment + 1);
-            m_data = (T *)realloc(m_data, m_capacity * sizeof(T));
+            m_data = (T *)q_check_ptr(realloc(m_data, m_capacity * sizeof(T)));
         }
     }
 
diff --git a/src/gui/inputmethod/qcoefepinputcontext_p.h b/src/gui/inputmethod/qcoefepinputcontext_p.h
index 90d47f9..b17d9c7 100644
--- a/src/gui/inputmethod/qcoefepinputcontext_p.h
+++ b/src/gui/inputmethod/qcoefepinputcontext_p.h
@@ -162,6 +162,8 @@ private:
     void enableSymbianCcpuSupport();
     void changeCBA(bool showCopyAndOrPaste);
     void copyOrCutTextToClipboard(const char *operation);
+    void getScreenCoordinatesForFepX(TPoint& aLeftSideOfBaseLine, TInt& aHeight, TInt& aAscent,
+            TInt aDocumentPosition) const;
 
     //From MEikCcpuEditor interface
 public:
diff --git a/src/gui/inputmethod/qcoefepinputcontext_s60.cpp b/src/gui/inputmethod/qcoefepinputcontext_s60.cpp
index ed7411f..44e0df0 100644
--- a/src/gui/inputmethod/qcoefepinputcontext_s60.cpp
+++ b/src/gui/inputmethod/qcoefepinputcontext_s60.cpp
@@ -1465,40 +1465,49 @@ void QCoeFepInputContext::CancelFepInlineEdit()
 
     m_pendingTransactionCancel = true;
 
-    QList<QInputMethodEvent::Attribute> attributes;
-    QInputMethodEvent event(QLatin1String(""), attributes);
-    event.setCommitString(QLatin1String(""), 0, 0);
-    m_preeditString.clear();
-    m_inlinePosition = 0;
-    sendEvent(event);
-
-    // Sync with native side editor state. Native side can then do various operations
-    // based on editor state, such as removing 'exact word bubble'.
-    if (!m_pendingInputCapabilitiesChanged)
-        ReportAknEdStateEvent(MAknEdStateObserver::EAknSyncEdwinState);
+    QT_TRY {
+        QList<QInputMethodEvent::Attribute> attributes;
+        QInputMethodEvent event(QLatin1String(""), attributes);
+        event.setCommitString(QLatin1String(""), 0, 0);
+        m_preeditString.clear();
+        m_inlinePosition = 0;
+        sendEvent(event);
+
+        // Sync with native side editor state. Native side can then do various operations
+        // based on editor state, such as removing 'exact word bubble'.
+        if (!m_pendingInputCapabilitiesChanged)
+            ReportAknEdStateEvent(MAknEdStateObserver::EAknSyncEdwinState);
+    } QT_CATCH(const std::exception&) {
+        m_preeditString.clear();
+        m_inlinePosition = 0;
+    }
 
     m_pendingTransactionCancel = false;
 }
 
 TInt QCoeFepInputContext::DocumentLengthForFep() const
 {
-    QWidget *w = focusWidget();
-    if (!w)
-        return 0;
+    QT_TRY {
+        QWidget *w = focusWidget();
+        if (!w)
+            return 0;
 
-    QVariant variant = w->inputMethodQuery(Qt::ImSurroundingText);
+        QVariant variant = w->inputMethodQuery(Qt::ImSurroundingText);
 
-    int size = variant.value<QString>().size() + m_preeditString.size();
+        int size = variant.value<QString>().size() + m_preeditString.size();
 
-    // To fix an issue with backspaces not being generated if document size is zero,
-    // fake document length to be at least one always, except when dealing with
-    // hidden text widgets, where this faking would generate extra asterisk. Since the
-    // primary use of hidden text widgets is password fields, they are unlikely to
-    // support multiple lines anyway.
-    if (size == 0 && !(m_textCapabilities & TCoeInputCapabilities::ESecretText))
-        size = 1;
+        // To fix an issue with backspaces not being generated if document size is zero,
+        // fake document length to be at least one always, except when dealing with
+        // hidden text widgets, where this faking would generate extra asterisk. Since the
+        // primary use of hidden text widgets is password fields, they are unlikely to
+        // support multiple lines anyway.
+        if (size == 0 && !(m_textCapabilities & TCoeInputCapabilities::ESecretText))
+            size = 1;
 
-    return size;
+        return size;
+    } QT_CATCH(const std::exception&) {
+        return 0;
+    }
 }
 
 TInt QCoeFepInputContext::DocumentMaximumLengthForFep() const
@@ -1540,42 +1549,46 @@ void QCoeFepInputContext::SetCursorSelectionForFepL(const TCursorSelection& aCur
 
 void QCoeFepInputContext::GetCursorSelectionForFep(TCursorSelection& aCursorSelection) const
 {
-    QWidget *w = focusWidget();
-    if (!w) {
-        aCursorSelection.SetSelection(0,0);
-        return;
-    }
+    QT_TRY {
+        QWidget *w = focusWidget();
+        if (!w) {
+            aCursorSelection.SetSelection(0,0);
+            return;
+        }
 
-    int cursor = w->inputMethodQuery(Qt::ImCursorPosition).toInt() + m_preeditString.size();
-    int anchor = w->inputMethodQuery(Qt::ImAnchorPosition).toInt() + m_preeditString.size();
+        int cursor = w->inputMethodQuery(Qt::ImCursorPosition).toInt() + m_preeditString.size();
+        int anchor = w->inputMethodQuery(Qt::ImAnchorPosition).toInt() + m_preeditString.size();
 
-    // If the position is stored, use that value, so that word replacement from proposed word
-    // lists are added to the correct position.
-    if (m_cachedCursorAndAnchorPosition != -1) {
-        cursor = m_cachedCursorAndAnchorPosition;
-        anchor = m_cachedCursorAndAnchorPosition;
-    }
-    QString text = w->inputMethodQuery(Qt::ImSurroundingText).value<QString>();
-    int combinedSize = text.size() + m_preeditString.size();
-    if (combinedSize < anchor || combinedSize < cursor) {
-        // ### TODO! FIXME! QTBUG-5050
-        // This is a hack to prevent crashing in 4.6 with QLineEdits that use input masks.
-        // The root problem is that cursor position is relative to displayed text instead of the
-        // actual text we get.
-        //
-        // To properly fix this we would need to know the displayText of QLineEdits instead
-        // of just the text, which on itself should be a trivial change. The difficulties start
-        // when we need to commit the changes back to the QLineEdit, which would have to be somehow
-        // able to handle displayText, too.
-        //
-        // Until properly fixed, the cursor and anchor positions will not reflect correct positions
-        // for masked QLineEdits, unless all the masked positions are filled in order so that
-        // cursor position relative to the displayed text matches position relative to actual text.
-        aCursorSelection.iAnchorPos = combinedSize;
-        aCursorSelection.iCursorPos = combinedSize;
-    } else {
-        aCursorSelection.iAnchorPos = anchor;
-        aCursorSelection.iCursorPos = cursor;
+        // If the position is stored, use that value, so that word replacement from proposed word
+        // lists are added to the correct position.
+        if (m_cachedCursorAndAnchorPosition != -1) {
+            cursor = m_cachedCursorAndAnchorPosition;
+            anchor = m_cachedCursorAndAnchorPosition;
+        }
+        QString text = w->inputMethodQuery(Qt::ImSurroundingText).value<QString>();
+        int combinedSize = text.size() + m_preeditString.size();
+        if (combinedSize < anchor || combinedSize < cursor) {
+            // ### TODO! FIXME! QTBUG-5050
+            // This is a hack to prevent crashing in 4.6 with QLineEdits that use input masks.
+            // The root problem is that cursor position is relative to displayed text instead of the
+            // actual text we get.
+            //
+            // To properly fix this we would need to know the displayText of QLineEdits instead
+            // of just the text, which on itself should be a trivial change. The difficulties start
+            // when we need to commit the changes back to the QLineEdit, which would have to be somehow
+            // able to handle displayText, too.
+            //
+            // Until properly fixed, the cursor and anchor positions will not reflect correct positions
+            // for masked QLineEdits, unless all the masked positions are filled in order so that
+            // cursor position relative to the displayed text matches position relative to actual text.
+            aCursorSelection.iAnchorPos = combinedSize;
+            aCursorSelection.iCursorPos = combinedSize;
+        } else {
+            aCursorSelection.iAnchorPos = anchor;
+            aCursorSelection.iCursorPos = cursor;
+        }
+    } QT_CATCH(const std::exception&) {
+        aCursorSelection.SetSelection(0,0);
     }
 }
 
@@ -1618,6 +1631,12 @@ void QCoeFepInputContext::GetFormatForFep(TCharFormat& aFormat, TInt /* aDocumen
 }
 
 void QCoeFepInputContext::GetScreenCoordinatesForFepL(TPoint& aLeftSideOfBaseLine, TInt& aHeight,
+        TInt& aAscent, TInt aDocumentPosition) const
+{
+    QT_TRYCATCH_LEAVING(getScreenCoordinatesForFepX(aLeftSideOfBaseLine, aHeight, aAscent, aDocumentPosition));
+}
+
+void QCoeFepInputContext::getScreenCoordinatesForFepX(TPoint& aLeftSideOfBaseLine, TInt& aHeight,
         TInt& aAscent, TInt /* aDocumentPosition */) const
 {
     QWidget *w = focusWidget();
@@ -1774,36 +1793,40 @@ TBool QCoeFepInputContext::CcpuIsFocused() const
 
 TBool QCoeFepInputContext::CcpuCanCut() const
 {
-    bool retval = false;
-    if (m_inDestruction)
-        return retval;
-    QWidget *w = focusWidget();
-    QObject *focusObject = 0;
-    if (!w) {
-        w = m_lastFocusedEditor;
-        focusObject = m_lastFocusedObject;
-    } else {
-        w = getQWidgetFromQGraphicsView(w, &focusObject);
-    }
-    if (w) {
-        QRect microFocus = w->inputMethodQuery(Qt::ImMicroFocus).toRect();
-        if (microFocus.isNull()) {
-            // For some reason, the editor does not have microfocus. Most probably,
-            // it is due to using native fullscreen editing mode with QML apps.
-            // Try accessing "selectedText" directly.
-            QObject *invokeTarget = w;
-            if (focusObject)
-                invokeTarget = focusObject;
-
-            QString selectedText = invokeTarget->property("selectedText").toString();
-            retval = !selectedText.isNull();
+    QT_TRY {
+        bool retval = false;
+        if (m_inDestruction)
+            return retval;
+        QWidget *w = focusWidget();
+        QObject *focusObject = 0;
+        if (!w) {
+            w = m_lastFocusedEditor;
+            focusObject = m_lastFocusedObject;
         } else {
-            int cursor = w->inputMethodQuery(Qt::ImCursorPosition).toInt();
-            int anchor = w->inputMethodQuery(Qt::ImAnchorPosition).toInt();
-            retval = cursor != anchor;
+            w = getQWidgetFromQGraphicsView(w, &focusObject);
         }
+        if (w) {
+            QRect microFocus = w->inputMethodQuery(Qt::ImMicroFocus).toRect();
+            if (microFocus.isNull()) {
+                // For some reason, the editor does not have microfocus. Most probably,
+                // it is due to using native fullscreen editing mode with QML apps.
+                // Try accessing "selectedText" directly.
+                QObject *invokeTarget = w;
+                if (focusObject)
+                    invokeTarget = focusObject;
+
+                QString selectedText = invokeTarget->property("selectedText").toString();
+                retval = !selectedText.isNull();
+            } else {
+                int cursor = w->inputMethodQuery(Qt::ImCursorPosition).toInt();
+                int anchor = w->inputMethodQuery(Qt::ImAnchorPosition).toInt();
+                retval = cursor != anchor;
+            }
+        }
+        return retval;
+    } QT_CATCH(const std::exception&) {
+        return EFalse;
     }
-    return retval;
 }
 
 void QCoeFepInputContext::CcpuCutL()
diff --git a/src/gui/kernel/qapplication_s60.cpp b/src/gui/kernel/qapplication_s60.cpp
index fe239f5..bb84491 100644
--- a/src/gui/kernel/qapplication_s60.cpp
+++ b/src/gui/kernel/qapplication_s60.cpp
@@ -1534,53 +1534,57 @@ bool QSymbianControl::hasFocusedAndVisibleChild(QWidget *parentWidget)
 
 void QSymbianControl::FocusChanged(TDrawNow /* aDrawNow */)
 {
-    if (m_ignoreFocusChanged || (qwidget->windowType() & Qt::WindowType_Mask) == Qt::Desktop)
-        return;
+    QT_TRY {
+        if (m_ignoreFocusChanged || (qwidget->windowType() & Qt::WindowType_Mask) == Qt::Desktop)
+            return;
 
 #ifdef Q_WS_S60
-    if (S60->splitViewLastWidget)
-        return;
+        if (S60->splitViewLastWidget)
+            return;
 #endif
 
-    // Popups never get focused, but still receive the FocusChanged when they are hidden.
-    if (QApplicationPrivate::popupWidgets != 0
-            || (qwidget->windowType() & Qt::Popup) == Qt::Popup)
-        return;
-
-    if (IsFocused() && IsVisible()) {
-        if (m_symbianPopupIsOpen) {
-            QWidget *fw = QApplication::focusWidget();
-            if (fw) {
-                QFocusEvent event(QEvent::FocusIn, Qt::PopupFocusReason);
-                QCoreApplication::sendEvent(fw, &event);
-            }
-            m_symbianPopupIsOpen = false;
-        }
+        // Popups never get focused, but still receive the FocusChanged when they are hidden.
+        if (QApplicationPrivate::popupWidgets != 0
+                || (qwidget->windowType() & Qt::Popup) == Qt::Popup)
+            return;
 
-        QApplication::setActiveWindow(qwidget->window());
-        qwidget->d_func()->setWindowIcon_sys(true);
-        qwidget->d_func()->setWindowTitle_sys(qwidget->windowTitle());
-#ifdef Q_WS_S60
-        if (qwidget->isWindow())
-            S60->setRecursiveDecorationsVisibility(qwidget, qwidget->windowState());
-#endif
-    } else {
-        QWidget *parentWindow = qwidget->window();
-        if (QApplication::activeWindow() == parentWindow && !hasFocusedAndVisibleChild(parentWindow)) {
-            if (CCoeEnv::Static()->AppUi()->IsDisplayingMenuOrDialog() || S60->menuBeingConstructed) {
+        if (IsFocused() && IsVisible()) {
+            if (m_symbianPopupIsOpen) {
                 QWidget *fw = QApplication::focusWidget();
                 if (fw) {
-                    QFocusEvent event(QEvent::FocusOut, Qt::PopupFocusReason);
+                    QFocusEvent event(QEvent::FocusIn, Qt::PopupFocusReason);
                     QCoreApplication::sendEvent(fw, &event);
                 }
-                m_symbianPopupIsOpen = true;
-                return;
+                m_symbianPopupIsOpen = false;
             }
 
-            QApplication::setActiveWindow(0);
+            QApplication::setActiveWindow(qwidget->window());
+            qwidget->d_func()->setWindowIcon_sys(true);
+            qwidget->d_func()->setWindowTitle_sys(qwidget->windowTitle());
+#ifdef Q_WS_S60
+            if (qwidget->isWindow())
+                S60->setRecursiveDecorationsVisibility(qwidget, qwidget->windowState());
+#endif
+        } else {
+            QWidget *parentWindow = qwidget->window();
+            if (QApplication::activeWindow() == parentWindow && !hasFocusedAndVisibleChild(parentWindow)) {
+                if (CCoeEnv::Static()->AppUi()->IsDisplayingMenuOrDialog() || S60->menuBeingConstructed) {
+                    QWidget *fw = QApplication::focusWidget();
+                    if (fw) {
+                        QFocusEvent event(QEvent::FocusOut, Qt::PopupFocusReason);
+                        QCoreApplication::sendEvent(fw, &event);
+                    }
+                    m_symbianPopupIsOpen = true;
+                    return;
+                }
+
+                QApplication::setActiveWindow(0);
+            }
         }
+        // else { We don't touch the active window unless we were explicitly activated or deactivated }
+    } QT_CATCH(const std::exception&) {
+        // ignore errors
     }
-    // else { We don't touch the active window unless we were explicitly activated or deactivated }
 }
 
 void QSymbianControl::handleClientAreaChange()
@@ -2377,19 +2381,25 @@ int QApplication::symbianProcessEvent(const QSymbianEvent *event)
 
     QScopedLoopLevelCounter counter(d->threadData);
 
-    if (d->eventDispatcher->filterEvent(const_cast<QSymbianEvent *>(event)))
-        return 1;
+    QT_TRY {
+        if (d->eventDispatcher->filterEvent(const_cast<QSymbianEvent *>(event)))
+            return 1;
+
+        QWidget *w = qApp ? qApp->focusWidget() : 0;
+        if (w) {
+            QInputContext *ic = w->inputContext();
+            if (ic && ic->symbianFilterEvent(w, event))
+                return 1;
+        }
 
-    QWidget *w = qApp ? qApp->focusWidget() : 0;
-    if (w) {
-        QInputContext *ic = w->inputContext();
-        if (ic && ic->symbianFilterEvent(w, event))
+        if (symbianEventFilter(event))
             return 1;
+    } QT_CATCH(const std::exception& ex) {
+        // don't allow an exception to stop exit command handling
+        if (event->type() != QSymbianEvent::CommandEvent || event->command() != EEikCmdExit)
+            QT_RETHROW;
     }
 
-    if (symbianEventFilter(event))
-        return 1;
-
     switch (event->type()) {
     case QSymbianEvent::WindowServerEvent:
         return d->symbianProcessWsEvent(event);
diff --git a/src/gui/painting/qgraphicssystemex_symbian.cpp b/src/gui/painting/qgraphicssystemex_symbian.cpp
index 5a182ff..5bfd5a8 100644
--- a/src/gui/painting/qgraphicssystemex_symbian.cpp
+++ b/src/gui/painting/qgraphicssystemex_symbian.cpp
@@ -74,7 +74,7 @@ bool QSymbianGraphicsSystemEx::hasBCM2727()
 #if 1
     // Hacky but fast ~0ms.
     const char* vendor = eglQueryString(display, EGL_VENDOR);
-    if (strstr(vendor, "Broadcom")) {
+    if (vendor && strstr(vendor, "Broadcom")) {
         const TUid KIvePropertyCat = {0x2726beef};
         enum TIvePropertyChipType {
             EVCBCM2727B1 = 0x00000000,