tdf#154040 use a SdrObjKind::NewFrame for frame creation in writer

Instead of (ab)using SdrObjKind::NONE for the temporary, empty
SdrObject instance in writer when creating a new frame, use a new
SdrObjKind::NewFrame kind for the object and use a empty SdrObject
instance EmptyObject - minimal implementation of SdrObject).

Change-Id: I0277a8f0cf7bfd428e106258ae8710b77e62c41b
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/149924
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>
Reviewed-by: Tomaž Vajngerl <quikee@gmail.com>

6 files changed, 25 insertions, 17 deletions

diff --git a/include/svx/svdobjkind.hxx b/include/svx/svdobjkind.hxx
index e6063bc10ce57..d25eba0a00278 100644
--- a/include/svx/svdobjkind.hxx
+++ b/include/svx/svdobjkind.hxx
@@ -141,7 +141,8 @@ enum class SdrObjKind : sal_uInt16
     ReportDesignSubReport = 506,
 
     // writer, arbitrarily place at 600
-    SwFlyDrawObjIdentifier = 601
+    SwFlyDrawObjIdentifier = 601,
+    NewFrame = 602
 };
 
 inline constexpr bool IsInventorE3D(SdrObjKind e)
diff --git a/svx/source/svdraw/svdcrtv.cxx b/svx/source/svdraw/svdcrtv.cxx
index 8c3c0750377f9..3a27e56694c74 100644
--- a/svx/source/svdraw/svdcrtv.cxx
+++ b/svx/source/svdraw/svdcrtv.cxx
@@ -414,7 +414,7 @@ bool SdrCreateView::ImpBegCreateObj(SdrInventor nInvent, SdrObjKind nIdent, cons
                 // object should not be created. Since it is possible to use it as a helper
                 // object (e.g. in letting the user define an area with the interactive
                 // construction) at least no items should be set at that object.
-                if(nInvent != SdrInventor::Default || nIdent != SdrObjKind::NONE)
+                if(nInvent != SdrInventor::Default || nIdent != SdrObjKind::NewFrame)
                 {
                     mpCurrentCreate->SetMergedItemSet(maDefaultAttr);
                 }
@@ -734,11 +734,11 @@ void SdrCreateView::ShowCreateObj(/*OutputDevice* pOut, sal_Bool bFull*/)
         // overlay objects instead.
         bool bUseSolidDragging(IsSolidDragging());
 
-        // #i101648# check if dragged object is a naked SdrObject (not
-        // a derivation). This is e.g. used in SW Frame construction
-        // as placeholder. Do not use SolidDragging for naked SdrObjects,
-        // they cannot have a valid optical representation
-        if(bUseSolidDragging && SdrObjKind::NONE == mpCurrentCreate->GetObjIdentifier())
+        // #i101648# check if dragged object is a SdrObjKind::NewFrame.
+        // This is e.g. used in SW Frame construction as placeholder.
+        // Do not use SolidDragging for SdrObjKind::NewFrame kind of objects,
+        // they cannot have a valid optical representation.
+        if (bUseSolidDragging && SdrObjKind::NewFrame == mpCurrentCreate->GetObjIdentifier())
         {
             bUseSolidDragging = false;
         }
diff --git a/svx/source/svdraw/svdobj.cxx b/svx/source/svdraw/svdobj.cxx
index 8f3d2e7eb12a2..ab9aa7a9dcf1d 100644
--- a/svx/source/svdraw/svdobj.cxx
+++ b/svx/source/svdraw/svdobj.cxx
@@ -3197,6 +3197,9 @@ rtl::Reference<SdrObject> SdrObjFactory::CreateObjectFromFactory(SdrModel& rSdrM
 namespace
 {
 
+// SdrObject subclass, which represents an empty object of a
+// certain type (kind).
+template <SdrObjKind OBJECT_KIND, SdrInventor OBJECT_INVENTOR>
 class EmptyObject final : public SdrObject
 {
 private:
@@ -3221,17 +3224,17 @@ public:
 
     SdrInventor GetObjInventor() const override
     {
-        return SdrInventor::Default;
+        return OBJECT_INVENTOR;
     }
 
     SdrObjKind GetObjIdentifier() const override
     {
-        return SdrObjKind::NONE;
+        return OBJECT_KIND;
     }
 
     void NbcRotate(const Point& /*rRef*/, Degree100 /*nAngle*/, double /*sinAngle*/, double /*cosAngle*/) override
     {
-        assert(false);
+        assert(false); // should not be called for this kind of objects
     }
 };
 
@@ -3329,7 +3332,7 @@ rtl::Reference<SdrObject> SdrObjFactory::MakeNewObject(
                 }
             }
             break;
-            case SdrObjKind::NONE: pObj = new EmptyObject(rSdrModel); break;
+            case SdrObjKind::NONE: pObj = nullptr; break;
             case SdrObjKind::Group       : pObj=new SdrObjGroup(rSdrModel);                 break;
             case SdrObjKind::Polygon       : pObj=new SdrPathObj(rSdrModel, SdrObjKind::Polygon       ); break;
             case SdrObjKind::PolyLine       : pObj=new SdrPathObj(rSdrModel, SdrObjKind::PolyLine       ); break;
@@ -3352,7 +3355,11 @@ rtl::Reference<SdrObject> SdrObjFactory::MakeNewObject(
             case SdrObjKind::Media      : pObj=new SdrMediaObj(rSdrModel);               break;
 #endif
             case SdrObjKind::Table      : pObj=new sdr::table::SdrTableObj(rSdrModel);   break;
-            default: break;
+            case SdrObjKind::NewFrame: // used for frame creation in writer
+                pObj = new EmptyObject<SdrObjKind::NewFrame, SdrInventor::Default>(rSdrModel);
+                break;
+            default:
+                break;
         }
     }
 
diff --git a/sw/source/core/frmedt/feshview.cxx b/sw/source/core/frmedt/feshview.cxx
index 7d38371d6b721..be160057093e7 100644
--- a/sw/source/core/frmedt/feshview.cxx
+++ b/sw/source/core/frmedt/feshview.cxx
@@ -2070,7 +2070,7 @@ bool SwFEShell::ImpEndCreate()
         }
     }
 
-    if( SdrInventor::Default == rSdrObj.GetObjInventor() && rSdrObj.GetObjIdentifier() == SdrObjKind::NONE )
+    if (SdrInventor::Default == rSdrObj.GetObjInventor() && rSdrObj.GetObjIdentifier() == SdrObjKind::NewFrame)
     {
         // For OBJ_NONE a fly is inserted.
         const tools::Long nWidth = rBound.Right()  - rBound.Left();
diff --git a/sw/source/uibase/docvw/edtwin.cxx b/sw/source/uibase/docvw/edtwin.cxx
index 50ad58e1d7fd7..114fa3cea8a69 100644
--- a/sw/source/uibase/docvw/edtwin.cxx
+++ b/sw/source/uibase/docvw/edtwin.cxx
@@ -726,7 +726,7 @@ inline void SwEditWin::EnterArea()
  */
 void SwEditWin::InsFrame(sal_uInt16 nCols)
 {
-    StdDrawMode( SdrObjKind::NONE, false );
+    StdDrawMode(SdrObjKind::NewFrame, false);
     m_bInsFrame = true;
     m_nInsFrameColCount = nCols;
 }
diff --git a/sw/source/uibase/ribbar/drawbase.cxx b/sw/source/uibase/ribbar/drawbase.cxx
index 146f2ffde9ef8..4e77bbc1f6956 100644
--- a/sw/source/uibase/ribbar/drawbase.cxx
+++ b/sw/source/uibase/ribbar/drawbase.cxx
@@ -261,7 +261,7 @@ bool SwDrawBase::MouseButtonUp(const MouseEvent& rMEvt)
         }
         else
         {
-            if (SdrObjKind::NONE == nDrawMode)
+            if (SdrObjKind::NewFrame == nDrawMode)
             {
                 SwRewriter aRewriter;
 
@@ -275,7 +275,7 @@ bool SwDrawBase::MouseButtonUp(const MouseEvent& rMEvt)
                 CreateDefaultObjectAtPosWithSize(aPnt, Size(1000, 1000));
             }
 
-            if (SdrObjKind::NONE == nDrawMode)   // Text border inserted
+            if (SdrObjKind::NewFrame == nDrawMode)   // Text border inserted
             {
                 uno::Reference< frame::XDispatchRecorder > xRecorder =
                     m_pSh->GetView().GetViewFrame().GetBindings().GetRecorder();
@@ -303,7 +303,7 @@ bool SwDrawBase::MouseButtonUp(const MouseEvent& rMEvt)
                         m_pSh->SetFlyFrameAttr( aSet );
                 }
             }
-            if (m_pWin->GetSdrDrawMode() == SdrObjKind::NONE)
+            if (m_pWin->GetSdrDrawMode() == SdrObjKind::NewFrame)
             {
                 m_pSh->EndUndo();
             }