Fix Windows native file dialogs for use with QtQuick.

- Correct modality check.
- Allow for properties to be set if there is no native dialog.
- Make dialog thread for non-modal call back into dialog helper
  for exec().
- Introduce QWindowsFileDialogSharedData to contain data to be
  cached while no native dialog exists and to be updated by the
  change notifications of the IFileDialogEvent interface to avoid
  querying the dialog results after the dialog has closed. Reduce
  virtual methods of QWindowsNativeFileDialogBase accordingly.
  This also fixes a bug in the previous implementation causing
  the directory not to reported back since the native API would
  not return the directory after closing the dialog.
- Support nonmodal native dialogs when constructed on a QQuickWindow.
- Delete native dialogs after exec as QtQuick keeps the
  dialog instances around.

Change-Id: Id1169d6657d9476afe12fb9909c36cbd03aa2a40
Reviewed-by: Oliver Wolff <oliver.wolff@digia.com>
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>
Reviewed-by: Shawn Rutledge <shawn.rutledge@digia.com>

2 files changed, 254 insertions, 167 deletions

diff --git a/src/plugins/platforms/windows/qwindowsdialoghelpers.cpp b/src/plugins/platforms/windows/qwindowsdialoghelpers.cpp
index 9e5578d35d..16acf439a0 100644
--- a/src/plugins/platforms/windows/qwindowsdialoghelpers.cpp
+++ b/src/plugins/platforms/windows/qwindowsdialoghelpers.cpp
@@ -58,6 +58,10 @@
 #include <QtCore/QObject>
 #include <QtCore/QThread>
 #include <QtCore/QSysInfo>
+#include <QtCore/QSharedData>
+#include <QtCore/QExplicitlySharedDataPointer>
+#include <QtCore/QMutex>
+#include <QtCore/QMutexLocker>
 #include <QtCore/private/qsystemlibrary_p.h>
 
 #include "qtwindows_additional.h"
@@ -387,6 +391,9 @@ void eatMouseMove()
     Vista on) that mimick the behaviour of their QDialog
     counterparts as close as possible.
 
+    Instances of derived classes are controlled by
+    QWindowsDialogHelperBase-derived classes.
+
     A major difference is that there is only an exec(), which
     is a modal, blocking call; there is no non-blocking show().
     There 2 types of native dialogs:
@@ -401,6 +408,7 @@ void eatMouseMove()
        like close() can be called on them from event handlers.
     \endlist
 
+    \sa QWindowsDialogHelperBase
     \internal
     \ingroup qt-lighthouse-win
 */
@@ -411,7 +419,6 @@ class QWindowsNativeDialogBase : public QObject
 public:
     virtual void setWindowTitle(const QString &title) = 0;
     virtual void exec(HWND owner = 0) = 0;
-    virtual QPlatformDialogHelper::DialogCode result() const = 0;
 
 signals:
     void accepted();
@@ -432,12 +439,10 @@ protected:
     The native dialog is created in setVisible_sys() since
     then modality and the state of DontUseNativeDialog is known.
 
-    Modal dialogs are then started via the platformNativeDialogModalHelp(),
-    platformNativeDialogModalHelp() slots.
-    Non-modal dialogs are shown using a separate thread should
-    they support it.
+    Modal dialogs are then run by exec(). Non-modal dialogs are shown using a
+    separate thread started in show() should they support it.
 
-    \sa QWindowsDialogThread
+    \sa QWindowsDialogThread, QWindowsNativeDialogBase
     \internal
     \ingroup qt-lighthouse-win
 */
@@ -450,12 +455,6 @@ QWindowsDialogHelperBase<BaseClass>::QWindowsDialogHelperBase() :
 }
 
 template <class BaseClass>
-QWindowsDialogHelperBase<BaseClass>::~QWindowsDialogHelperBase()
-{
-    delete m_nativeDialog;
-}
-
-template <class BaseClass>
 QWindowsNativeDialogBase *QWindowsDialogHelperBase<BaseClass>::nativeDialog() const
 {
     if (!m_nativeDialog) {
@@ -466,6 +465,13 @@ QWindowsNativeDialogBase *QWindowsDialogHelperBase<BaseClass>::nativeDialog() co
 }
 
 template <class BaseClass>
+void QWindowsDialogHelperBase<BaseClass>::deleteNativeDialog()
+{
+    delete m_nativeDialog;
+    m_nativeDialog = 0;
+}
+
+template <class BaseClass>
 QWindowsNativeDialogBase *QWindowsDialogHelperBase<BaseClass>::ensureNativeDialog()
 {
     // Create dialog and apply common settings.
@@ -486,22 +492,18 @@ QWindowsNativeDialogBase *QWindowsDialogHelperBase<BaseClass>::ensureNativeDialo
 class QWindowsDialogThread : public QThread
 {
 public:
-    QWindowsDialogThread(QWindowsNativeDialogBase *dialog,
-                             HWND owner = 0) :
-        m_dialog(dialog), m_owner(owner) {}
-
+    QWindowsDialogThread(QPlatformDialogHelper *h) : m_helper(h) {}
     void run();
 
 private:
-    QWindowsNativeDialogBase *m_dialog;
-    const HWND m_owner;
+    QPlatformDialogHelper *m_helper;
 };
 
 void QWindowsDialogThread::run()
 {
     if (QWindowsContext::verboseDialogs)
         qDebug(">%s" , __FUNCTION__);
-    m_dialog->exec(m_owner);
+    m_helper->exec();
     deleteLater();
     if (QWindowsContext::verboseDialogs)
         qDebug("<%s" , __FUNCTION__);
@@ -512,7 +514,7 @@ bool QWindowsDialogHelperBase<BaseClass>::show(Qt::WindowFlags,
                                                    Qt::WindowModality windowModality,
                                                    QWindow *parent)
 {
-    const bool modal = (windowModality == Qt::ApplicationModal);
+    const bool modal = (windowModality != Qt::NonModal);
     if (parent) {
         m_ownerWindow = QWindowsWindow::handleOf(parent);
     } else {
@@ -521,12 +523,12 @@ bool QWindowsDialogHelperBase<BaseClass>::show(Qt::WindowFlags,
     if (QWindowsContext::verboseDialogs)
         qDebug("%s modal=%d native=%p parent=%p" ,
                __FUNCTION__, modal, m_nativeDialog, m_ownerWindow);
-    if (!modal && !supportsNonModalDialog())
+    if (!modal && !supportsNonModalDialog(parent))
         return false; // Was it changed in-between?
     if (!ensureNativeDialog())
         return false;
     if (!modal) { // Modal dialogs are shown in separate slot.
-        QWindowsDialogThread *thread = new QWindowsDialogThread(m_nativeDialog, m_ownerWindow);
+        QWindowsDialogThread *thread = new QWindowsDialogThread(this);
         thread->start();
     }
     return true;
@@ -545,8 +547,10 @@ void QWindowsDialogHelperBase<BaseClass>::exec()
 {
     if (QWindowsContext::verboseDialogs)
         qDebug("%s" , __FUNCTION__);
-    if (QWindowsNativeDialogBase *nd = nativeDialog())
+    if (QWindowsNativeDialogBase *nd = nativeDialog()) {
          nd->exec(m_ownerWindow);
+         deleteNativeDialog();
+    }
 }
 
 static inline bool snapToDefaultButtonHint()
@@ -568,6 +572,101 @@ QVariant QWindowsDialogHelperBase<BaseClass>::styleHint(QPlatformDialogHelper::S
 }
 
 /*!
+    \class QWindowsFileDialogSharedData
+    \brief Explicitly shared file dialog parameters that are not in QFileDialogOptions.
+
+    Contain Parameters that need to be cached while the native dialog does not
+    exist yet. In addition, the data are updated by the change notifications of the
+    IFileDialogEvent, as querying them after the dialog has closed
+    does not reliably work. Provides thread-safe setters (for the non-modal case).
+
+    \internal
+    \ingroup qt-lighthouse-win
+    \sa QFileDialogOptions
+*/
+
+class QWindowsFileDialogSharedData
+{
+public:
+    QWindowsFileDialogSharedData() : m_data(new Data) {}
+    void fromOptions(const QSharedPointer<QFileDialogOptions> &o);
+
+    QString directory() const;
+    void setDirectory(const QString &);
+    QString selectedNameFilter() const;
+    void setSelectedNameFilter(const QString &);
+    QStringList selectedFiles() const;
+    void setSelectedFiles(const QStringList &);
+    QString selectedFile() const;
+
+private:
+    class Data : public QSharedData {
+    public:
+        QString directory;
+        QString selectedNameFilter;
+        QStringList selectedFiles;
+        QMutex mutex;
+    };
+    QExplicitlySharedDataPointer<Data> m_data;
+};
+
+inline QString QWindowsFileDialogSharedData::directory() const
+{
+    m_data->mutex.lock();
+    const QString result = m_data->directory;
+    m_data->mutex.unlock();
+    return result;
+}
+
+inline void QWindowsFileDialogSharedData::setDirectory(const QString &d)
+{
+    QMutexLocker (&m_data->mutex);
+    m_data->directory = d;
+}
+
+inline QString QWindowsFileDialogSharedData::selectedNameFilter() const
+{
+    m_data->mutex.lock();
+    const QString result = m_data->selectedNameFilter;
+    m_data->mutex.unlock();
+    return result;
+}
+
+inline void QWindowsFileDialogSharedData::setSelectedNameFilter(const QString &f)
+{
+    QMutexLocker (&m_data->mutex);
+    m_data->selectedNameFilter = f;
+}
+
+inline QStringList QWindowsFileDialogSharedData::selectedFiles() const
+{
+    m_data->mutex.lock();
+    const QStringList result = m_data->selectedFiles;
+    m_data->mutex.unlock();
+    return result;
+}
+
+inline QString QWindowsFileDialogSharedData::selectedFile() const
+{
+    const QStringList files = selectedFiles();
+    return files.isEmpty() ? QString() : files.front();
+}
+
+inline void QWindowsFileDialogSharedData::setSelectedFiles(const QStringList &f)
+{
+    QMutexLocker (&m_data->mutex);
+    m_data->selectedFiles = f;
+}
+
+inline void QWindowsFileDialogSharedData::fromOptions(const QSharedPointer<QFileDialogOptions> &o)
+{
+    QMutexLocker (&m_data->mutex);
+    m_data->directory = o->initialDirectory();
+    m_data->selectedFiles = o->initiallySelectedFiles();
+    m_data->selectedNameFilter = o->initiallySelectedNameFilter();
+}
+
+/*!
     \class QWindowsNativeFileDialogEventHandler
     \brief Listens to IFileDialog events and forwards them to QWindowsNativeFileDialogBase
 
@@ -609,7 +708,7 @@ public:
     }
 
     // IFileDialogEvents methods
-    IFACEMETHODIMP OnFileOk(IFileDialog *) { return S_OK; }
+    IFACEMETHODIMP OnFileOk(IFileDialog *);
     IFACEMETHODIMP OnFolderChange(IFileDialog *) { return S_OK; }
     IFACEMETHODIMP OnFolderChanging(IFileDialog *, IShellItem *);
     IFACEMETHODIMP OnHelp(IFileDialog *) { return S_OK; }
@@ -658,29 +757,33 @@ class QWindowsNativeFileDialogBase : public QWindowsNativeDialogBase
 public:
     ~QWindowsNativeFileDialogBase();
 
-    inline static QWindowsNativeFileDialogBase *create(QFileDialogOptions::AcceptMode am);
+    inline static QWindowsNativeFileDialogBase *create(QFileDialogOptions::AcceptMode am, const QWindowsFileDialogSharedData &data);
 
     virtual void setWindowTitle(const QString &title);
     inline void setMode(QFileDialogOptions::FileMode mode, QFileDialogOptions::FileDialogOptions options);
     inline void setDirectory(const QString &directory);
+    inline void updateDirectory() { setDirectory(m_data.directory()); }
     inline QString directory() const;
     virtual void exec(HWND owner = 0);
     inline void setNameFilters(const QStringList &f);
     inline void selectNameFilter(const QString &filter);
+    inline void updateSelectedNameFilter() { selectNameFilter(m_data.selectedNameFilter()); }
     inline QString selectedNameFilter() const;
     bool hideFiltersDetails() const    { return m_hideFiltersDetails; }
     void setHideFiltersDetails(bool h) { m_hideFiltersDetails = h; }
     void setDefaultSuffix(const QString &s);
     inline void setLabelText(QFileDialogOptions::DialogLabel l, const QString &text);
 
-    virtual QPlatformDialogHelper::DialogCode result() const
-        { return fileResult(); }
-    virtual QPlatformDialogHelper::DialogCode fileResult(QStringList *fileResult = 0) const = 0;
+    // Return the selected files for tracking in OnSelectionChanged().
     virtual QStringList selectedFiles() const = 0;
+    // Return the result for tracking in OnFileOk(). Differs from selection for
+    // example by appended default suffixes, etc.
+    virtual QStringList dialogResult() const = 0;
 
     inline void onFolderChange(IShellItem *);
     inline void onSelectionChange();
     inline void onTypeChange();
+    inline bool onFileOk();
 
 signals:
     void directoryEntered(const QString& directory);
@@ -691,23 +794,28 @@ public slots:
     virtual void close() { m_fileDialog->Close(S_OK); }
 
 protected:
-    QWindowsNativeFileDialogBase();
+    explicit QWindowsNativeFileDialogBase(const QWindowsFileDialogSharedData &data);
     bool init(const CLSID &clsId, const IID &iid);
     inline IFileDialog * fileDialog() const { return m_fileDialog; }
     static QString itemPath(IShellItem *item);
     static int itemPaths(IShellItemArray *items, QStringList *fileResult = 0);
     static IShellItem *shellItem(const QString &path);
 
+    const QWindowsFileDialogSharedData &data() const { return m_data; }
+    QWindowsFileDialogSharedData &data() { return m_data; }
+
 private:
     IFileDialog *m_fileDialog;
     IFileDialogEvents *m_dialogEvents;
     DWORD m_cookie;
     QStringList m_nameFilters;
     bool m_hideFiltersDetails;
+    QWindowsFileDialogSharedData m_data;
 };
 
-QWindowsNativeFileDialogBase::QWindowsNativeFileDialogBase() :
-    m_fileDialog(0), m_dialogEvents(0), m_cookie(0), m_hideFiltersDetails(false)
+QWindowsNativeFileDialogBase::QWindowsNativeFileDialogBase(const QWindowsFileDialogSharedData &data) :
+    m_fileDialog(0), m_dialogEvents(0), m_cookie(0), m_hideFiltersDetails(false),
+    m_data(data)
 {
 }
 
@@ -763,15 +871,17 @@ IShellItem *QWindowsNativeFileDialogBase::shellItem(const QString &path)
             return result;
     }
 #endif
-    qErrnoWarning("%s: SHCreateItemFromParsingName()) failed", __FUNCTION__);
+    qErrnoWarning("%s: SHCreateItemFromParsingName(%s)) failed", __FUNCTION__, qPrintable(path));
     return 0;
 }
 
 void QWindowsNativeFileDialogBase::setDirectory(const QString &directory)
 {
-    if (IShellItem *psi = QWindowsNativeFileDialogBase::shellItem(directory)) {
-        m_fileDialog->SetFolder(psi);
-        psi->Release();
+    if (!directory.isEmpty()) {
+        if (IShellItem *psi = QWindowsNativeFileDialogBase::shellItem(directory)) {
+            m_fileDialog->SetFolder(psi);
+            psi->Release();
+        }
     }
 }
 
@@ -977,14 +1087,16 @@ static int indexOfNameFilter(const QStringList &filters, const QString &needle)
 
 void QWindowsNativeFileDialogBase::selectNameFilter(const QString &filter)
 {
+    if (filter.isEmpty())
+        return;
     const int index = indexOfNameFilter(m_nameFilters, filter);
-    if (index >= 0) {
-        m_fileDialog->SetFileTypeIndex(index + 1); // one-based.
-    } else {
+    if (index < 0) {
         qWarning("%s: Invalid parameter '%s' not found in '%s'.",
                  __FUNCTION__, qPrintable(filter),
                  qPrintable(m_nameFilters.join(QStringLiteral(", "))));
+        return;
     }
+    m_fileDialog->SetFileTypeIndex(index + 1); // one-based.
 }
 
 QString QWindowsNativeFileDialogBase::selectedNameFilter() const
@@ -1002,6 +1114,7 @@ void QWindowsNativeFileDialogBase::onFolderChange(IShellItem *item)
 {
     if (item) {
         const QString directory = QWindowsNativeFileDialogBase::itemPath(item);
+        m_data.setDirectory(directory);
         emit directoryEntered(directory);
     }
 }
@@ -1009,13 +1122,23 @@ void QWindowsNativeFileDialogBase::onFolderChange(IShellItem *item)
 void QWindowsNativeFileDialogBase::onSelectionChange()
 {
     const QStringList current = selectedFiles();
+    m_data.setSelectedFiles(current);
     if (current.size() == 1)
         emit currentChanged(current.front());
 }
 
 void QWindowsNativeFileDialogBase::onTypeChange()
 {
-    emit filterSelected(selectedNameFilter());
+    const QString filter = selectedNameFilter();
+    m_data.setSelectedNameFilter(filter);
+    emit filterSelected(filter);
+}
+
+bool QWindowsNativeFileDialogBase::onFileOk()
+{
+    // Store selected files as GetResults() returns invalid data after the dialog closes.
+    m_data.setSelectedFiles(dialogResult());
+    return true;
 }
 
 HRESULT QWindowsNativeFileDialogEventHandler::OnFolderChanging(IFileDialog *, IShellItem *item)
@@ -1036,6 +1159,11 @@ HRESULT QWindowsNativeFileDialogEventHandler::OnTypeChange(IFileDialog *)
     return S_OK;
 }
 
+HRESULT QWindowsNativeFileDialogEventHandler::OnFileOk(IFileDialog *)
+{
+    return m_nativeFileDialog->onFileOk() ? S_OK : S_FALSE;
+}
+
 /*!
     \class QWindowsNativeSaveFileDialog
     \brief Windows native file save dialog wrapper around IFileSaveDialog.
@@ -1049,8 +1177,10 @@ HRESULT QWindowsNativeFileDialogEventHandler::OnTypeChange(IFileDialog *)
 class QWindowsNativeSaveFileDialog : public QWindowsNativeFileDialogBase
 {
 public:
-    virtual QPlatformDialogHelper::DialogCode fileResult(QStringList *fileResult = 0) const;
+    explicit QWindowsNativeSaveFileDialog(const QWindowsFileDialogSharedData &data) :
+        QWindowsNativeFileDialogBase(data) {}
     virtual QStringList selectedFiles() const;
+    virtual QStringList dialogResult() const;
 };
 
 // Append a suffix from the name filter "Foo files (*.foo;*.bar)"
@@ -1073,17 +1203,13 @@ static inline QString appendSuffix(const QString &fileName, const QString &filte
     return fileName + QLatin1Char('.') + filter.mid(suffixPos, endPos - suffixPos);
 }
 
-QPlatformDialogHelper::DialogCode QWindowsNativeSaveFileDialog::fileResult(QStringList *result /* = 0 */) const
+QStringList QWindowsNativeSaveFileDialog::dialogResult() const
 {
-    if (result)
-        result->clear();
+    QStringList result;
     IShellItem *item = 0;
-    const HRESULT hr = fileDialog()->GetResult(&item);
-    if (FAILED(hr) || !item)
-        return QPlatformDialogHelper::Rejected;
-    if (result)
-        result->push_back(appendSuffix(QWindowsNativeFileDialogBase::itemPath(item), selectedNameFilter()));
-    return QPlatformDialogHelper::Accepted;
+    if (SUCCEEDED(fileDialog()->GetResult(&item)) && item)
+        result.push_back(appendSuffix(QWindowsNativeFileDialogBase::itemPath(item), selectedNameFilter()));
+    return result;
 }
 
 QStringList QWindowsNativeSaveFileDialog::selectedFiles() const
@@ -1109,23 +1235,23 @@ QStringList QWindowsNativeSaveFileDialog::selectedFiles() const
 class QWindowsNativeOpenFileDialog : public QWindowsNativeFileDialogBase
 {
 public:
-    virtual QPlatformDialogHelper::DialogCode fileResult(QStringList *fileResult = 0) const;
+    explicit QWindowsNativeOpenFileDialog(const QWindowsFileDialogSharedData &data) :
+        QWindowsNativeFileDialogBase(data) {}
     virtual QStringList selectedFiles() const;
+    virtual QStringList dialogResult() const;
 
 private:
     inline IFileOpenDialog *openFileDialog() const
         { return static_cast<IFileOpenDialog *>(fileDialog()); }
 };
 
-QPlatformDialogHelper::DialogCode QWindowsNativeOpenFileDialog::fileResult(QStringList *result /* = 0 */) const
+QStringList QWindowsNativeOpenFileDialog::dialogResult() const
 {
-    if (result)
-        result->clear();
+    QStringList result;
     IShellItemArray *items = 0;
-    const HRESULT hr = openFileDialog()->GetResults(&items);
-    if (SUCCEEDED(hr) && items && QWindowsNativeFileDialogBase::itemPaths(items, result) > 0)
-        return QPlatformDialogHelper::Accepted;
-    return QPlatformDialogHelper::Rejected;
+    if (SUCCEEDED(openFileDialog()->GetResults(&items)) && items)
+        QWindowsNativeFileDialogBase::itemPaths(items, &result);
+    return result;
 }
 
 QStringList QWindowsNativeOpenFileDialog::selectedFiles() const
@@ -1144,17 +1270,18 @@ QStringList QWindowsNativeOpenFileDialog::selectedFiles() const
     QFileDialog::AcceptMode.
 */
 
-QWindowsNativeFileDialogBase *QWindowsNativeFileDialogBase::create(QFileDialogOptions::AcceptMode am)
+QWindowsNativeFileDialogBase *QWindowsNativeFileDialogBase::create(QFileDialogOptions::AcceptMode am,
+                                                                   const QWindowsFileDialogSharedData &data)
 {
     QWindowsNativeFileDialogBase *result = 0;
     if (am == QFileDialogOptions::AcceptOpen) {
-        result = new QWindowsNativeOpenFileDialog;
+        result = new QWindowsNativeOpenFileDialog(data);
         if (!result->init(CLSID_FileOpenDialog, IID_IFileOpenDialog)) {
             delete result;
             return 0;
         }
     } else {
-        result = new QWindowsNativeSaveFileDialog;
+        result = new QWindowsNativeSaveFileDialog(data);
         if (!result->init(CLSID_FileSaveDialog, IID_IFileSaveDialog)) {
             delete result;
             return 0;
@@ -1163,16 +1290,17 @@ QWindowsNativeFileDialogBase *QWindowsNativeFileDialogBase::create(QFileDialogOp
     return result;
 }
 
+static inline bool isQQuickWindow(const QWindow *w = 0)
+{
+    return w && w->inherits("QQuickWindow");
+}
+
 /*!
     \class QWindowsFileDialogHelper
     \brief Helper for native Windows file dialogs
 
-    Non-modal dialogs are disabled for now. The functionality is
-    implemented in principle, however there are failures
-    when querying the results from a dialog run in another thread.
-    This could probably be fixed be calling CoInitializeEx() with
-    the right parameters from each thread. The problem is though
-    that calls to CoInitialize() occur in several places in Qt.
+    For Qt 4 compatibility, do not create native non-modal dialogs on widgets,
+    but only on QQuickWindows, which do not have a fallback.
 
     \internal
     \ingroup qt-lighthouse-win
@@ -1182,8 +1310,9 @@ class QWindowsFileDialogHelper : public QWindowsDialogHelperBase<QPlatformFileDi
 {
 public:
     QWindowsFileDialogHelper() {}
-    virtual bool supportsNonModalDialog() const { return false; }
-
+    // For Qt 4 compatibility, do not create native non-modal dialogs on widgets,
+    // but only on QQuickWindows, which do not have a fallback.
+    virtual bool supportsNonModalDialog(const QWindow *parent = 0) const { return isQQuickWindow(parent); }
     virtual bool defaultNameFilterDisables() const
         { return true; }
     virtual void setDirectory(const QString &directory);
@@ -1199,11 +1328,14 @@ private:
     virtual QWindowsNativeDialogBase *createNativeDialog();
     inline QWindowsNativeFileDialogBase *nativeFileDialog() const
         { return static_cast<QWindowsNativeFileDialogBase *>(nativeDialog()); }
+
+    // Cache for the case no native dialog is created.
+    QWindowsFileDialogSharedData m_data;
 };
 
 QWindowsNativeDialogBase *QWindowsFileDialogHelper::createNativeDialog()
 {
-    QWindowsNativeFileDialogBase *result = QWindowsNativeFileDialogBase::create(options()->acceptMode());
+    QWindowsNativeFileDialogBase *result = QWindowsNativeFileDialogBase::create(options()->acceptMode(), m_data);
     if (!result)
         return 0;
     QObject::connect(result, SIGNAL(accepted()), this, SIGNAL(accept()));
@@ -1217,6 +1349,7 @@ QWindowsNativeDialogBase *QWindowsFileDialogHelper::createNativeDialog()
 
     // Apply settings.
     const QSharedPointer<QFileDialogOptions> &opts = options();
+    m_data.fromOptions(opts);
     result->setWindowTitle(opts->windowTitle());
     result->setMode(opts->fileMode(), opts->options());
     result->setHideFiltersDetails(opts->testOption(QFileDialogOptions::HideNameFilterDetails));
@@ -1227,12 +1360,8 @@ QWindowsNativeDialogBase *QWindowsFileDialogHelper::createNativeDialog()
         result->setLabelText(QFileDialogOptions::FileName, opts->labelText(QFileDialogOptions::FileName));
     if (opts->isLabelExplicitlySet(QFileDialogOptions::Accept))
         result->setLabelText(QFileDialogOptions::Accept, opts->labelText(QFileDialogOptions::Accept));
-    const QString initialDirectory = opts->initialDirectory();
-    if (!initialDirectory.isEmpty())
-        result->setDirectory(initialDirectory);
-    const QString initialNameFilter = opts->initiallySelectedNameFilter();
-    if (!initialNameFilter.isEmpty())
-        result->selectNameFilter(initialNameFilter);
+    result->updateDirectory();
+    result->updateSelectedNameFilter();
     const QString defaultSuffix = opts->defaultSuffix();
     if (!defaultSuffix.isEmpty())
         result->setDefaultSuffix(defaultSuffix);
@@ -1244,15 +1373,14 @@ void QWindowsFileDialogHelper::setDirectory(const QString &directory)
     if (QWindowsContext::verboseDialogs)
         qDebug("%s %s" , __FUNCTION__, qPrintable(directory));
 
-    if (QWindowsNativeFileDialogBase *nfd = nativeFileDialog())
-        nfd->setDirectory(directory);
+    m_data.setDirectory(directory);
+    if (hasNativeDialog())
+        nativeFileDialog()->updateDirectory();
 }
 
 QString QWindowsFileDialogHelper::directory() const
 {
-    if (const QWindowsNativeFileDialogBase *nfd = nativeFileDialog())
-        return nfd->directory();
-    return QString();
+    return m_data.directory();
 }
 
 void QWindowsFileDialogHelper::selectFile(const QString & /* filename */)
@@ -1262,13 +1390,7 @@ void QWindowsFileDialogHelper::selectFile(const QString & /* filename */)
 
 QStringList QWindowsFileDialogHelper::selectedFiles() const
 {
-    QStringList files;
-    if (const QWindowsNativeFileDialogBase *nfd = nativeFileDialog())
-        nfd->fileResult(&files);
-    if (QWindowsContext::verboseDialogs)
-        qDebug("%s files='%s'" , __FUNCTION__,
-               qPrintable(files.join(QStringLiteral(", "))));
-    return files;
+    return m_data.selectedFiles();
 }
 
 void QWindowsFileDialogHelper::setFilter()
@@ -1287,15 +1409,14 @@ void QWindowsFileDialogHelper::setNameFilters(const QStringList &filters)
 
 void QWindowsFileDialogHelper::selectNameFilter(const QString &filter)
 {
-    if (QWindowsNativeFileDialogBase *nfd = nativeFileDialog())
-        nfd->selectNameFilter(filter);
+    m_data.setSelectedNameFilter(filter);
+    if (hasNativeDialog())
+        nativeFileDialog()->updateSelectedNameFilter();
 }
 
 QString QWindowsFileDialogHelper::selectedNameFilter() const
 {
-    if (const QWindowsNativeFileDialogBase *nfd = nativeFileDialog())
-        return nfd->selectedNameFilter();
-    return QString();
+    return m_data.selectedNameFilter();
 }
 
 #ifndef Q_OS_WINCE
@@ -1319,20 +1440,12 @@ class QWindowsXpNativeFileDialog : public QWindowsNativeDialogBase
 public:
     typedef QSharedPointer<QFileDialogOptions> OptionsPtr;
 
-    static QWindowsXpNativeFileDialog *create(const OptionsPtr &options);
+    static QWindowsXpNativeFileDialog *create(const OptionsPtr &options, const QWindowsFileDialogSharedData &data);
 
     virtual void setWindowTitle(const QString &t) { m_title =  t; }
     virtual void exec(HWND owner = 0);
     virtual QPlatformDialogHelper::DialogCode result() const { return m_result; }
 
-    void setDirectory(const QString &d) { m_directory = d; }
-    QString directory() const { return m_directory; }
-    void selectFile(const QString &f) { m_initialFile = f; }
-    QStringList selectedFiles() const { return m_selectedFiles; }
-    void setNameFilters(const QStringList &n) { m_nameFilters = n; }
-    void selectNameFilter(const QString &f);
-    QString selectedNameFilter() const { return m_selectedNameFilter; }
-
     int existingDirCallback(HWND hwnd, UINT uMsg, LPARAM lParam);
 
 public slots:
@@ -1342,19 +1455,15 @@ private:
     typedef BOOL (APIENTRY *PtrGetOpenFileNameW)(LPOPENFILENAMEW);
     typedef BOOL (APIENTRY *PtrGetSaveFileNameW)(LPOPENFILENAMEW);
 
-    explicit QWindowsXpNativeFileDialog(const OptionsPtr &options);
+    explicit QWindowsXpNativeFileDialog(const OptionsPtr &options, const QWindowsFileDialogSharedData &data);
     void populateOpenFileName(OPENFILENAME *ofn, HWND owner) const;
     QStringList execExistingDir(HWND owner);
     QStringList execFileNames(HWND owner, int *selectedFilterIndex) const;
 
     const OptionsPtr m_options;
     QString m_title;
-    QString m_directory;
-    QString m_initialFile;
-    QStringList m_selectedFiles;
-    QString m_selectedNameFilter;
-    QStringList m_nameFilters;
     QPlatformDialogHelper::DialogCode m_result;
+    QWindowsFileDialogSharedData m_data;
 
     static PtrGetOpenFileNameW m_getOpenFileNameW;
     static PtrGetSaveFileNameW m_getSaveFileNameW;
@@ -1363,7 +1472,7 @@ private:
 QWindowsXpNativeFileDialog::PtrGetOpenFileNameW QWindowsXpNativeFileDialog::m_getOpenFileNameW = 0;
 QWindowsXpNativeFileDialog::PtrGetSaveFileNameW QWindowsXpNativeFileDialog::m_getSaveFileNameW = 0;
 
-QWindowsXpNativeFileDialog *QWindowsXpNativeFileDialog::create(const OptionsPtr &options)
+QWindowsXpNativeFileDialog *QWindowsXpNativeFileDialog::create(const OptionsPtr &options, const QWindowsFileDialogSharedData &data)
 {
     // GetOpenFileNameW() GetSaveFileName() are resolved
     // dynamically as not to create a dependency on Comdlg32, which
@@ -1374,51 +1483,33 @@ QWindowsXpNativeFileDialog *QWindowsXpNativeFileDialog::create(const OptionsPtr
         m_getSaveFileNameW = (PtrGetSaveFileNameW)(library.resolve("GetSaveFileNameW"));
     }
     if (m_getOpenFileNameW && m_getSaveFileNameW)
-        return new QWindowsXpNativeFileDialog(options);
+        return new QWindowsXpNativeFileDialog(options, data);
     return 0;
 }
 
-QWindowsXpNativeFileDialog::QWindowsXpNativeFileDialog(const OptionsPtr &options) :
-    m_options(options), m_result(QPlatformDialogHelper::Rejected)
+QWindowsXpNativeFileDialog::QWindowsXpNativeFileDialog(const OptionsPtr &options,
+                                                       const QWindowsFileDialogSharedData &data) :
+    m_options(options), m_result(QPlatformDialogHelper::Rejected), m_data(data)
 {
-    const QStringList nameFilters = m_options->nameFilters();
-    if (!nameFilters.isEmpty())
-        setNameFilters(nameFilters);
-    const QString initialDirectory = m_options->initialDirectory();
-    if (!initialDirectory.isEmpty())
-        setDirectory(initialDirectory);
-    const QString initialNameFilter = m_options->initiallySelectedNameFilter();
-    if (!initialNameFilter.isEmpty())
-        selectNameFilter(initialNameFilter);
-    const QStringList selectedFiles = m_options->initiallySelectedFiles();
-    if (!selectedFiles.isEmpty())
-        selectFile(selectedFiles.front());
     setWindowTitle(m_options->windowTitle());
 }
 
-void QWindowsXpNativeFileDialog::selectNameFilter(const QString &f)
-{
-    const int index = indexOfNameFilter(m_nameFilters, f);
-    if (index >= 0)
-        m_selectedNameFilter = m_nameFilters.at(index);
-}
-
 void QWindowsXpNativeFileDialog::exec(HWND owner)
 {
     int selectedFilterIndex = -1;
-    m_selectedFiles = m_options->fileMode() == QFileDialogOptions::DirectoryOnly ?
+    const QStringList selectedFiles =
+        m_options->fileMode() == QFileDialogOptions::DirectoryOnly ?
         execExistingDir(owner) : execFileNames(owner, &selectedFilterIndex);
+    m_data.setSelectedFiles(selectedFiles);
     QWindowsDialogs::eatMouseMove();
-    if (m_selectedFiles.isEmpty()) {
+    if (selectedFiles.isEmpty()) {
         m_result = QPlatformDialogHelper::Rejected;
         emit rejected();
     } else {
-        if (selectedFilterIndex >= 0 && selectedFilterIndex < m_nameFilters.size()) {
-            m_selectedNameFilter = m_nameFilters.at(selectedFilterIndex);
-        } else {
-            m_selectedNameFilter.clear();
-        }
-        m_directory = QFileInfo(m_selectedFiles.front()).absolutePath();
+        const QStringList nameFilters = m_options->nameFilters();
+        if (selectedFilterIndex >= 0 && selectedFilterIndex < nameFilters.size())
+            m_data.setSelectedNameFilter(nameFilters.at(selectedFilterIndex));
+        m_data.setDirectory(QFileInfo(selectedFiles.front()).absolutePath());
         m_result = QPlatformDialogHelper::Accepted;
         emit accepted();
     }
@@ -1442,9 +1533,11 @@ typedef PIDLIST_ABSOLUTE qt_LpItemIdList;
 int QWindowsXpNativeFileDialog::existingDirCallback(HWND hwnd, UINT uMsg, LPARAM lParam)
 {
     switch (uMsg) {
-    case BFFM_INITIALIZED:
-        if (!m_initialFile.isEmpty())
-            SendMessage(hwnd, BFFM_SETSELECTION, TRUE, LPARAM(m_initialFile.utf16()));
+    case BFFM_INITIALIZED: {
+        const QString initialFile = m_data.selectedFile();
+        if (!initialFile.isEmpty())
+            SendMessage(hwnd, BFFM_SETSELECTION, TRUE, LPARAM(initialFile.utf16()));
+    }
         break;
     case BFFM_SELCHANGED: {
         wchar_t path[MAX_PATH];
@@ -1516,7 +1609,7 @@ void QWindowsXpNativeFileDialog::populateOpenFileName(OPENFILENAME *ofn, HWND ow
         *ptr++ = 0;
     }
     *ptr = 0;
-    const int nameFilterIndex = indexOfNameFilter(m_nameFilters, m_selectedNameFilter);
+    const int nameFilterIndex = indexOfNameFilter(m_options->nameFilters(), m_data.selectedNameFilter());
     if (nameFilterIndex >= 0)
         ofn->nFilterIndex = nameFilterIndex + 1; // 1..n based.
     // lpstrFile receives the initial selection and is the buffer
@@ -1524,10 +1617,10 @@ void QWindowsXpNativeFileDialog::populateOpenFileName(OPENFILENAME *ofn, HWND ow
     // will not show.
     ofn->nMaxFile = 65535;
     const QString initiallySelectedFile =
-        QDir::toNativeSeparators(m_initialFile).remove(QLatin1Char('<')).
+        QDir::toNativeSeparators(m_data.selectedFile()).remove(QLatin1Char('<')).
             remove(QLatin1Char('>')).remove(QLatin1Char('"')).remove(QLatin1Char('|'));
     ofn->lpstrFile = qStringToWCharArray(initiallySelectedFile, ofn->nMaxFile);
-    ofn->lpstrInitialDir = qStringToWCharArray(QDir::toNativeSeparators(m_directory));
+    ofn->lpstrInitialDir = qStringToWCharArray(QDir::toNativeSeparators(m_data.directory()));
     ofn->lpstrTitle = (wchar_t*)m_title.utf16();
     // Determine lpstrDefExt. Note that the current MSDN docs document this
     // member wrong. It should rather be documented as "the default extension
@@ -1596,8 +1689,7 @@ class QWindowsXpFileDialogHelper : public QWindowsDialogHelperBase<QPlatformFile
 {
 public:
     QWindowsXpFileDialogHelper() {}
-    virtual bool supportsNonModalDialog() const { return false; }
-
+    virtual bool supportsNonModalDialog(const QWindow *parent = 0) const { return isQQuickWindow(parent); }
     virtual bool defaultNameFilterDisables() const
         { return true; }
     virtual void setDirectory(const QString &directory);
@@ -1613,11 +1705,14 @@ private:
     virtual QWindowsNativeDialogBase *createNativeDialog();
     inline QWindowsXpNativeFileDialog *nativeFileDialog() const
         { return static_cast<QWindowsXpNativeFileDialog *>(nativeDialog()); }
+
+    QWindowsFileDialogSharedData m_data;
 };
 
 QWindowsNativeDialogBase *QWindowsXpFileDialogHelper::createNativeDialog()
 {
-    if (QWindowsNativeDialogBase *result = QWindowsXpNativeFileDialog::create(options())) {
+    m_data.fromOptions(options());
+    if (QWindowsXpNativeFileDialog *result = QWindowsXpNativeFileDialog::create(options(), m_data)) {
         QObject::connect(result, SIGNAL(accepted()), this, SIGNAL(accept()));
         QObject::connect(result, SIGNAL(rejected()), this, SIGNAL(reject()));
         return result;
@@ -1627,47 +1722,37 @@ QWindowsNativeDialogBase *QWindowsXpFileDialogHelper::createNativeDialog()
 
 void QWindowsXpFileDialogHelper::setDirectory(const QString &directory)
 {
-    if (QWindowsXpNativeFileDialog *nfd = nativeFileDialog())
-        nfd->setDirectory(directory);
+    m_data.setDirectory(directory); // Dialog cannot be updated at run-time.
 }
 
 QString QWindowsXpFileDialogHelper::directory() const
 {
-    if (const QWindowsXpNativeFileDialog *nfd = nativeFileDialog())
-        return nfd->directory();
-    return QString();
+    return m_data.directory();
 }
 
 void QWindowsXpFileDialogHelper::selectFile(const QString &filename)
 {
-    if (QWindowsXpNativeFileDialog *nfd = nativeFileDialog())
-        nfd->selectFile(filename);
+    m_data.setSelectedFiles(QStringList(filename)); // Dialog cannot be updated at run-time.
 }
 
 QStringList QWindowsXpFileDialogHelper::selectedFiles() const
 {
-    if (const QWindowsXpNativeFileDialog *nfd = nativeFileDialog())
-        return nfd->selectedFiles();
-    return QStringList();
+    return m_data.selectedFiles();
 }
 
-void QWindowsXpFileDialogHelper::setNameFilters(const QStringList &n)
+void QWindowsXpFileDialogHelper::setNameFilters(const QStringList &)
 {
-    if (QWindowsXpNativeFileDialog *nfd = nativeFileDialog())
-        nfd->setNameFilters(n);
+    // Dialog cannot be updated at run-time.
 }
 
 void QWindowsXpFileDialogHelper::selectNameFilter(const QString &f)
 {
-    if (QWindowsXpNativeFileDialog *nfd = nativeFileDialog())
-        nfd->selectNameFilter(f);
+    m_data.setSelectedNameFilter(f); // Dialog cannot be updated at run-time.
 }
 
 QString QWindowsXpFileDialogHelper::selectedNameFilter() const
 {
-    if (const QWindowsXpNativeFileDialog *nfd = nativeFileDialog())
-        return nfd->selectedNameFilter();
-    return QString();
+    return m_data.selectedNameFilter();
 }
 
 #endif // Q_OS_WINCE
diff --git a/src/plugins/platforms/windows/qwindowsdialoghelpers.h b/src/plugins/platforms/windows/qwindowsdialoghelpers.h
index c656f72d6e..9ec93f1b4c 100644
--- a/src/plugins/platforms/windows/qwindowsdialoghelpers.h
+++ b/src/plugins/platforms/windows/qwindowsdialoghelpers.h
@@ -65,6 +65,7 @@ template <class BaseClass>
 class QWindowsDialogHelperBase : public BaseClass
 {
 public:
+    ~QWindowsDialogHelperBase() { deleteNativeDialog(); }
 
     virtual void exec();
     virtual bool show(Qt::WindowFlags windowFlags,
@@ -73,12 +74,13 @@ public:
     virtual void hide();
     virtual QVariant styleHint(QPlatformDialogHelper::StyleHint) const;
 
-    virtual bool supportsNonModalDialog() const { return true; }
+    virtual bool supportsNonModalDialog(const QWindow * /* parent */ = 0) const { return true; }
 
 protected:
     QWindowsDialogHelperBase();
-    ~QWindowsDialogHelperBase();
     QWindowsNativeDialogBase *nativeDialog() const;
+    inline bool hasNativeDialog() const { return m_nativeDialog; }
+    void deleteNativeDialog();
 
 private:
     virtual QWindowsNativeDialogBase *createNativeDialog() = 0;