KDE4: sleep in yield for native file picker

As it seems to be the only way to poll the clipboard, reintroduce

 m_pApplication->clipboard()->setProperty(
    "useEventLoopWhenWaiting", true );

To prevent crashes, disable event processing in the Qt thread while
the dialog is open.

Instead this applies the same workaround as the Windows backend to
sleep a ms, which keeps the FP dialogs more usable, but feels like
a horrible workaround.

This is still slower then running processEvent in Yield but still
much better then the current situation.

Change-Id: I10c422f1c0d7448d4a7ad28e57a32ed2cb42f48f

vcl/unx/kde4/KDE4FilePicker.cxx

@@ -38,6 +38,7 @@
 
 #include "KDE4FilePicker.hxx"
 #include "FPServiceInfo.hxx"
+#include "KDEXLib.hxx"
 
 /* ********* Hack, but needed because of conflicting types... */
 #define Region QtXRegion
@@ -113,10 +114,11 @@ QString toQString(const OUString& s)
 // KDE4FilePicker
 
 
-KDE4FilePicker::KDE4FilePicker( const uno::Reference<uno::XComponentContext>& )
+KDE4FilePicker::KDE4FilePicker( const uno::Reference<uno::XComponentContext>&, KDEXLib *xlib )
     : KDE4FilePicker_Base(_helperMutex)
     , _resMgr( ResMgr::CreateResMgr("fps_office") )
     , allowRemoteUrls( false )
+    , _mXLib( xlib )
 {
     _extraControls = new QWidget();
     _layout = new QGridLayout(_extraControls);
@@ -261,8 +263,11 @@ sal_Int16 SAL_CALL KDE4FilePicker::execute()
     _dialog->filterWidget()->setEditable(false);
 
     // We're entering a nested loop.
-    // Release the yield mutex to prevent deadlocks.
+    // Prevent yield calls, which would crash LO.
+
+    _mXLib->freezeYield( true );
     int result = _dialog->exec();
+    _mXLib->freezeYield( false );
 
     // HACK: KFileDialog uses KConfig("kdeglobals") for saving some settings
     // (such as the auto-extension flag), but that doesn't update KGlobal::config()

vcl/unx/kde4/KDE4FilePicker.hxx

@@ -40,6 +40,7 @@
 class KFileDialog;
 class QWidget;
 class QLayout;
+class KDEXLib;
 
 class ResMgr;
 
@@ -82,8 +83,10 @@ protected:
 
     bool allowRemoteUrls;
 
+    KDEXLib* _mXLib;
+
 public:
-    KDE4FilePicker( const ::com::sun::star::uno::Reference< ::com::sun::star::uno::XComponentContext >& );
+    KDE4FilePicker( const ::com::sun::star::uno::Reference< ::com::sun::star::uno::XComponentContext >&, KDEXLib* );
     virtual ~KDE4FilePicker();
 
     // XFilePickerNotifier

vcl/unx/kde4/KDEXLib.cxx

@@ -58,7 +58,8 @@
 KDEXLib::KDEXLib() :
     SalXLib(),  m_bStartupDone(false), m_pApplication(0),
     m_pFreeCmdLineArgs(0), m_pAppCmdLineArgs(0), m_nFakeCmdLineArgs( 0 ),
-    eventLoopType( LibreOfficeEventLoop )
+    eventLoopType( LibreOfficeEventLoop ),
+    m_bYieldFrozen( false )
 {
     // the timers created here means they belong to the main thread
     connect( &timeoutTimer, SIGNAL( timeout()), this, SLOT( timeoutActivated()));
@@ -213,6 +214,7 @@ void KDEXLib::setupEventLoop()
         eventLoopType = GlibEventLoop;
         old_gpoll = g_main_context_get_poll_func( NULL );
         g_main_context_set_poll_func( NULL, gpoll_wrapper );
+        m_pApplication->clipboard()->setProperty( "useEventLoopWhenWaiting", true );
         return;
     }
 #endif
@@ -272,6 +274,17 @@ void KDEXLib::Yield( bool bWait, bool bHandleAllCurrentEvents )
         return SalXLib::Yield( bWait, bHandleAllCurrentEvents );
     }
 
+    if( m_bYieldFrozen ) {
+        if( qApp->thread() != QThread::currentThread() ) {
+            QAbstractEventDispatcher* dispatcher = QAbstractEventDispatcher::instance( qApp->thread() );
+            if( dispatcher->hasPendingEvents() ) {
+                struct timespec delay = {0, ( 1000000 )};
+                nanosleep(&delay, NULL);
+            }
+        }
+        return;
+    }
+
     // if we are the main thread (which is where the event processing is done),
     // good, just do it
     if( qApp->thread() == QThread::currentThread()) {
@@ -389,7 +402,7 @@ uno::Reference< ui::dialogs::XFilePicker2 > KDEXLib::createFilePicker(
         SalYieldMutexReleaser aReleaser;
         return Q_EMIT createFilePickerSignal( xMSF );
     }
-    return uno::Reference< ui::dialogs::XFilePicker2 >( new KDE4FilePicker( xMSF ) );
+    return uno::Reference< ui::dialogs::XFilePicker2 >( new KDE4FilePicker( xMSF, this ) );
 }
 
 #include "KDEXLib.moc"

vcl/unx/kde4/KDEXLib.hxx

@@ -52,6 +52,7 @@ class KDEXLib : public QObject, public SalXLib
         QTimer timeoutTimer;
         QTimer userEventTimer;
         enum { LibreOfficeEventLoop, GlibEventLoop, QtUnixEventLoop } eventLoopType;
+        bool m_bYieldFrozen;
 
     private:
         void setupEventLoop();
@@ -84,6 +85,7 @@ class KDEXLib : public QObject, public SalXLib
         virtual void Wakeup();
         virtual void PostUserEvent();
 
+        void freezeYield(bool freeze) { m_bYieldFrozen = freeze; }
         void doStartup();
 
     public Q_SLOTS: