SwDBManager::MergeMailFiles: set unique fly names at the end of the merge

When generating a unique fly name, we have to iterate over all the
existing flys to find out what's the first not used one, so doing this
for every new fly inserted by mail merge is O(n^2).

During import, we already skip this and only do it once at the end of
the import, which is O(n).

Fix the performance problem by skipping the unique fly name generating
when we produce a combined mail merge document as well, and just
generate them once the mail merge is complete.

For a test document having 12 text frames and 2000 mail merge records,
the times for css::text::MailMerge::execute() is 9m37.330s -> 8m18.811s.

Conflicts:
sw/inc/doc.hxx
sw/source/core/doc/DocumentLayoutManager.cxx
sw/source/uibase/dbui/dbmgr.cxx

Change-Id: Idfa8e9fe3acc93f1138f5bb12c2419c1492f8ff1

1 files changed, 4 insertions, 0 deletions

diff --git a/sw/inc/doc.hxx b/sw/inc/doc.hxx
index 86aae2817d6c..c7d7af8de5ef 100644
--- a/sw/inc/doc.hxx
+++ b/sw/inc/doc.hxx
@@ -436,6 +436,7 @@ private:
     bool mbCopyIsMove            : 1;    ///< TRUE: Copy is a hidden Move.
     bool mbVisibleLinks          : 1;    ///< TRUE: Links are inserted visibly.
     bool mbInReading             : 1;    ///< TRUE: Document is in the process of being read.
+    bool mbInMailMerge           : 1;    //< TRUE: Document is in the process of being written by mail merge.
     bool mbInXMLImport           : 1;    ///< TRUE: During xml import, attribute portion building is not necessary.
     bool mbUpdateTOX             : 1;    ///< TRUE: After loading document, update TOX.
     bool mbInLoadAsynchron       : 1;    ///< TRUE: Document is in the process of being loaded asynchronously.
@@ -1428,6 +1429,9 @@ public:
     bool IsInReading() const                    { return mbInReading; }
     void SetInReading( bool bNew )              { mbInReading = bNew; }
 
+    bool IsInMailMerge() const                  { return mbInMailMerge; }
+    void SetInMailMerge( bool bNew )            { mbInMailMerge = bNew; }
+
     bool IsClipBoard() const                    { return mbClipBoard; }
     /// N.B.: must be called right after constructor! (@see GetXmlIdRegistry)
     void SetClipBoard( bool bNew )              { mbClipBoard = bNew; }