disable KFileDialog usage if QClipboard can recurse

Change-Id: If23a365b96c1634c2f8940f6ece973089dc3151f

configure.ac

@@ -11275,6 +11275,33 @@ int main(int argc, char *argv[])
             # Remove meta object data
             rm -f "${TSTBASE}."*
 
+            AC_MSG_CHECKING([whether Qt avoids QClipboard recursion caused by posted events])
+
+            # Prepare meta object data
+            TSTBASE="tst_exclude_posted_events"
+            TSTMOC="${SRC_ROOT}/vcl/unx/kde4/${TSTBASE}"
+            ln -fs "${TSTMOC}.hxx"
+            $MOC4 "${TSTBASE}.hxx" -o "${TSTBASE}.moc"
+
+            AC_RUN_IFELSE([AC_LANG_SOURCE([[
+#include "tst_exclude_posted_events.moc"
+
+int main(int argc, char *argv[])
+{
+    QCoreApplication app(argc, argv);
+    exit(tst_excludePostedEvents());
+    return 0;
+}
+            ]])],[
+                AC_MSG_RESULT([yes])
+            ],[
+                AC_MSG_RESULT([no])
+                AC_MSG_WARN([native KDE4 file pickers will be disabled at runtime - fix your Qt4 library!])
+            ])
+
+            # Remove meta object data
+            rm -f "${TSTBASE}."*
+
             LIBS=$save_LIBS
             CXXFLAGS=$save_CXXFLAGS
             AC_LANG_POP([C++])

vcl/CustomTarget_kde4_moc.mk

@@ -12,7 +12,8 @@ $(eval $(call gb_CustomTarget_CustomTarget,vcl/unx/kde4))
 $(call gb_CustomTarget_get_target,vcl/unx/kde4) : \
 	$(call gb_CustomTarget_get_workdir,vcl/unx/kde4)/KDEXLib.moc \
 	$(call gb_CustomTarget_get_workdir,vcl/unx/kde4)/KDE4FilePicker.moc \
-	$(call gb_CustomTarget_get_workdir,vcl/unx/kde4)/tst_exclude_socket_notifiers.moc
+	$(call gb_CustomTarget_get_workdir,vcl/unx/kde4)/tst_exclude_socket_notifiers.moc \
+	$(call gb_CustomTarget_get_workdir,vcl/unx/kde4)/tst_exclude_posted_events.moc
 
 $(call gb_CustomTarget_get_workdir,vcl/unx/kde4)/%.moc : \
 		$(SRCDIR)/vcl/unx/kde4/%.hxx \

vcl/unx/kde4/KDESalInstance.cxx

@@ -35,7 +35,7 @@ uno::Reference< ui::dialogs::XFilePicker2 > KDESalInstance::createFilePicker(
     const uno::Reference< uno::XComponentContext >& xMSF )
 {
     KDEXLib* kdeXLib = static_cast<KDEXLib*>( mpXLib );
-    if (kdeXLib->haveQt4SocketExcludeFix())
+    if (kdeXLib->allowKdeDialogs())
         return uno::Reference< ui::dialogs::XFilePicker2 >(
             kdeXLib->createFilePicker(xMSF) );
     else

vcl/unx/kde4/KDEXLib.cxx

@@ -47,13 +47,14 @@
 #if KDE_HAVE_GLIB
 #include "KDE4FilePicker.hxx"
 #include "tst_exclude_socket_notifiers.moc"
+#include "tst_exclude_posted_events.moc"
 #endif
 
 KDEXLib::KDEXLib() :
     SalXLib(),  m_bStartupDone(false), m_pApplication(0),
     m_pFreeCmdLineArgs(0), m_pAppCmdLineArgs(0), m_nFakeCmdLineArgs( 0 ),
     m_frameWidth( -1 ), m_isGlibEventLoopType(false),
-    m_haveQt4SocketExcludeFix(false)
+    m_allowKdeDialogs(false)
 {
     // the timers created here means they belong to the main thread.
     // As the timeoutTimer runs the LO event queue, which may block on a dialog,
@@ -187,9 +188,14 @@ void KDEXLib::Init()
 
 #if KDE_HAVE_GLIB
     m_isGlibEventLoopType = QAbstractEventDispatcher::instance()->inherits( "QEventDispatcherGlib" );
-    if (m_isGlibEventLoopType && (0 == tst_processEventsExcludeSocket()))
+    // Using KDE dialogs (and their nested event loops) works only with a proper event loop integration
+    // that will release SolarMutex when waiting for more events.
+    // Moreover there are bugs in Qt event loop code that allow QClipboard recursing because the event
+    // loop processes also events that it should not at that point, so no dialogs in that case either.
+    if (m_isGlibEventLoopType && (0 == tst_processEventsExcludeSocket()) && tst_excludePostedEvents() == 0 )
         // See http://bugreports.qt.nokia.com/browse/QTBUG-37380
-        m_haveQt4SocketExcludeFix = true;
+        // https://bugreports.qt-project.org/browse/QTBUG-34614
+        m_allowKdeDialogs = true;
 #endif
 
     setupEventLoop();
@@ -238,7 +244,7 @@ void KDEXLib::setupEventLoop()
     {
         old_gpoll = g_main_context_get_poll_func( NULL );
         g_main_context_set_poll_func( NULL, gpoll_wrapper );
-        if( m_haveQt4SocketExcludeFix )
+        if( m_allowKdeDialogs )
             m_pApplication->clipboard()->setProperty( "useEventLoopWhenWaiting", true );
         return;
     }

vcl/unx/kde4/KDEXLib.hxx

@@ -53,7 +53,7 @@ class KDEXLib : public QObject, public SalXLib
         QTimer userEventTimer;
         int m_frameWidth;
         bool m_isGlibEventLoopType;
-        bool m_haveQt4SocketExcludeFix;
+        bool m_allowKdeDialogs;
 
     private:
         void setupEventLoop();
@@ -88,7 +88,7 @@ class KDEXLib : public QObject, public SalXLib
         virtual void PostUserEvent() SAL_OVERRIDE;
 
         void doStartup();
-        bool haveQt4SocketExcludeFix() { return m_haveQt4SocketExcludeFix; }
+        bool allowKdeDialogs() { return m_allowKdeDialogs; }
 
     public Q_SLOTS:
         com::sun::star::uno::Reference< com::sun::star::ui::dialogs::XFilePicker2 >

vcl/unx/kde4/tst_exclude_posted_events.hxx

@@ -0,0 +1,70 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ *   Licensed to the Apache Software Foundation (ASF) under one or more
+ *   contributor license agreements. See the NOTICE file distributed
+ *   with this work for additional information regarding copyright
+ *   ownership. The ASF licenses this file to you under the Apache
+ *   License, Version 2.0 (the "License"); you may not use this file
+ *   except in compliance with the License. You may obtain a copy of
+ *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ *
+ * This code is based on the SocketEventsTester from the Qt4 test suite.
+ */
+
+#pragma once
+
+#include <qcoreapplication.h>
+#include <qeventloop.h>
+#include <qtimer.h>
+
+const QEvent::Type eventType = QEvent::User;
+
+class Test
+    : public QObject
+{
+    Q_OBJECT
+    public:
+        Test();
+        virtual bool event( QEvent* e );
+        bool processed;
+};
+
+Test::Test()
+    : processed( false )
+{
+}
+
+bool Test::event( QEvent* e )
+{
+    if( e->type() == eventType )
+        processed = true;
+    return QObject::event( e );
+}
+
+#define QVERIFY(a) \
+    if (!a) return 1;
+
+static int tst_excludePostedEvents()
+{
+    Test test;
+    QCoreApplication::postEvent( &test, new QEvent( eventType ));
+    QEventLoop loop;
+    QTimer::singleShot(200, &loop, SLOT(quit()));
+    loop.processEvents(QEventLoop::ExcludeUserInputEvents
+        | QEventLoop::ExcludeSocketNotifiers
+//        | QEventLoop::WaitForMoreEvents
+        | QEventLoop::X11ExcludeTimers);
+    QVERIFY( !test.processed );
+    QTimer::singleShot(200, &loop, SLOT(quit()));
+        loop.exec();
+    QVERIFY( test.processed );
+    return 0;
+}