tdf#95095: Don't create thumbnails on load.

Creating thumbnails is quite an expensive operation, so let's avoid that on
load, and do that only on the document save or document close.

In case the user chooses not to save a modified document, thumbnail is not
generated which can lead to document that has no thumbnail; but that's
probably a good tradeoff for the speedup.

Change-Id: I61bf5ec3fae9596e87963ac7a28ba6e4e52c4e99

sfx2/source/appl/sfxpicklist.cxx

@@ -159,7 +159,7 @@ SfxPickList::PickListEntry* SfxPickList::GetPickListEntry( sal_uInt32 nIndex )
         return 0;
 }
 
-void SfxPickList::AddDocumentToPickList( SfxObjectShell* pDocSh )
+void SfxPickList::AddDocumentToPickList(SfxObjectShell* pDocSh, bool bAvoidThumbnail)
 {
     SfxMedium *pMed = pDocSh->GetMedium();
     if( !pMed )
@@ -197,7 +197,7 @@ void SfxPickList::AddDocumentToPickList( SfxObjectShell* pDocSh )
     boost::optional<OUString> aThumbnail;
     // don't generate thumbnail when in headless mode, or on non-desktop (?)
 #if HAVE_FEATURE_DESKTOP
-    if (!pDocSh->IsModified() && !Application::IsHeadlessModeEnabled())
+    if (!bAvoidThumbnail && !pDocSh->IsModified() && !Application::IsHeadlessModeEnabled())
     {
         // not modified => the document matches what is in the shell
         SFX_ITEMSET_ARG( pMed->GetItemSet(), pEncryptionDataItem, SfxUnoAnyItem, SID_ENCRYPTIONDATA, false );
@@ -412,7 +412,7 @@ void SfxPickList::Notify( SfxBroadcaster&, const SfxHint& rHint )
 
             case SFX_EVENT_OPENDOC:
             {
-                AddDocumentToPickList(pDocSh);
+                AddDocumentToPickList(pDocSh, /* bAvoidThumbnail = */ true);
             }
             break;
 

sfx2/source/inc/sfxpicklist.hxx

@@ -58,7 +58,7 @@ class SfxPickList : public SfxListener
        certain requirements, e.g. being writable. Check implementation for requirement
        details.
      */
-    static void             AddDocumentToPickList( SfxObjectShell* pDocShell );
+    static void             AddDocumentToPickList(SfxObjectShell* pDocShell, bool bAvoidThumbnail = false);
 
     public:
         static SfxPickList& Get();