tdf#117866 cui: avoid deadlock in personalization dialog

The deadlock happened as the main thread wanted to join
SearchAndParseThread (while owning the solar mutex), but
SearchAndParseThread wanted to take the solar mutex to import a graphic.

Fix the deadlock by checking for the termination flag earlier, so we
don't take any new mutexes if termination was requested already.

Change-Id: Idddaadadc693610d9f31a14300b22aff8d452756
Reviewed-on: https://gerrit.libreoffice.org/55284Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>
Tested-by: Jenkins <ci@libreoffice.org>

cui/source/options/personalization.cxx

@@ -778,14 +778,16 @@ void SearchAndParseThread::execute()
                 continue;
             }
             INetURLObject aURLObj( sPreviewFile );
+
+            // Stop the thread if requested -- before taking the solar mutex.
+            if( !m_bExecute )
+                return;
+
             // for VCL to be able to create bitmaps / do visual changes in the thread
             SolarMutexGuard aGuard;
             aFilter.ImportGraphic( aGraphic, aURLObj );
             BitmapEx aBmp = aGraphic.GetBitmapEx();
 
-            if( !m_bExecute )
-                return;
-
             m_pPersonaDialog->SetImages( Image( aBmp ), nIndex++ );
             m_pPersonaDialog->setOptimalLayoutSize();
             m_pPersonaDialog->AddPersonaSetting( aPersonaSetting );