tdf#91383: sw: prevent style preview from actually creating styles

The dialog/sidebar should not actually create styles that don't exist yet,
because it messes up Undo and the (unused) styles are then unnecessarily
exported to documents.

Due to Writer's ... unusual SwDocStyleSheet class this is a bit tricky.

Add a new function GetItemSetForPreview() and use it from the style preview
code.

The implementation does not use FillPhysical so will temporarily create and
then delete any non-existing styles.

Skip page and numbering styles for now since they don't have a useful preview.

(regression from ca95307638207db5d662059aa61594151a13e927)

Change-Id: Id6ee30ea467fc24c991547a4c23a9ce14fdd86c7

6 files changed, 117 insertions, 37 deletions

diff --git a/include/svl/style.hxx b/include/svl/style.hxx
index dafa95ecf30b..3451312bfd53 100644
--- a/include/svl/style.hxx
+++ b/include/svl/style.hxx
@@ -139,6 +139,11 @@ public:
     virtual void   SetHelpId( const OUString& r, sal_uLong nId );
 
     virtual SfxItemSet& GetItemSet();
+    /// Due to writer's usual lack of sanity this is a separate function for
+    /// preview only; it shall not create the style in case it does not exist.
+    /// If the style has parents, it is _not_ required that the returned item
+    /// set has parents (i.e. use it for display purposes only).
+    virtual std::unique_ptr<SfxItemSet> GetItemSetForPreview();
 };
 
 /* Class to iterate and search on a SfxStyleSheetBasePool */
diff --git a/svl/source/items/style.cxx b/svl/source/items/style.cxx
index 5e9e5246004c..930bf92ca77c 100644
--- a/svl/source/items/style.cxx
+++ b/svl/source/items/style.cxx
@@ -284,6 +284,11 @@ SfxItemSet& SfxStyleSheetBase::GetItemSet()
     return *pSet;
 }
 
+std::unique_ptr<SfxItemSet> SfxStyleSheetBase::GetItemSetForPreview()
+{
+    return std::unique_ptr<SfxItemSet>(new SfxItemSet(GetItemSet()));
+}
+
 /**
  * Set help file and ID and return it
  */
diff --git a/svx/source/styles/CommonStylePreviewRenderer.cxx b/svx/source/styles/CommonStylePreviewRenderer.cxx
index 2d9ac3f5dd10..19bce5f5ef63 100644
--- a/svx/source/styles/CommonStylePreviewRenderer.cxx
+++ b/svx/source/styles/CommonStylePreviewRenderer.cxx
@@ -60,65 +60,67 @@ CommonStylePreviewRenderer::~CommonStylePreviewRenderer()
 
 bool CommonStylePreviewRenderer::recalculate()
 {
-    const SfxItemSet& aItemSet = mpStyle->GetItemSet();
-
     maFont = SvxFont();
 
+    std::unique_ptr<SfxItemSet> pItemSet(mpStyle->GetItemSetForPreview());
+
+    if (!pItemSet) return false;
+
     const SfxPoolItem* pItem;
 
-    if ((pItem = aItemSet.GetItem(SID_ATTR_CHAR_WEIGHT)) != nullptr)
+    if ((pItem = pItemSet->GetItem(SID_ATTR_CHAR_WEIGHT)) != nullptr)
     {
         maFont.SetWeight(static_cast<const SvxWeightItem*>(pItem)->GetWeight());
     }
-    if ((pItem = aItemSet.GetItem(SID_ATTR_CHAR_POSTURE)) != nullptr)
+    if ((pItem = pItemSet->GetItem(SID_ATTR_CHAR_POSTURE)) != nullptr)
     {
         maFont.SetItalic(static_cast<const SvxPostureItem*>(pItem)->GetPosture());
     }
-    if ((pItem = aItemSet.GetItem(SID_ATTR_CHAR_CONTOUR)) != nullptr)
+    if ((pItem = pItemSet->GetItem(SID_ATTR_CHAR_CONTOUR)) != nullptr)
     {
         maFont.SetOutline(static_cast< const SvxContourItem*>(pItem)->GetValue());
     }
-    if ((pItem = aItemSet.GetItem(SID_ATTR_CHAR_SHADOWED)) != nullptr)
+    if ((pItem = pItemSet->GetItem(SID_ATTR_CHAR_SHADOWED)) != nullptr)
     {
         maFont.SetShadow(static_cast<const SvxShadowedItem*>(pItem)->GetValue());
     }
-    if ((pItem = aItemSet.GetItem(SID_ATTR_CHAR_RELIEF)) != nullptr)
+    if ((pItem = pItemSet->GetItem(SID_ATTR_CHAR_RELIEF)) != nullptr)
     {
         maFont.SetRelief(static_cast<FontRelief>(static_cast<const SvxCharReliefItem*>(pItem)->GetValue()));
     }
-    if ((pItem = aItemSet.GetItem(SID_ATTR_CHAR_UNDERLINE)) != nullptr)
+    if ((pItem = pItemSet->GetItem(SID_ATTR_CHAR_UNDERLINE)) != nullptr)
     {
         maFont.SetUnderline(static_cast< const SvxUnderlineItem*>(pItem)->GetLineStyle());
     }
-    if ((pItem = aItemSet.GetItem(SID_ATTR_CHAR_OVERLINE)) != nullptr)
+    if ((pItem = pItemSet->GetItem(SID_ATTR_CHAR_OVERLINE)) != nullptr)
     {
         maFont.SetOverline(static_cast<FontUnderline>(static_cast<const SvxOverlineItem*>(pItem)->GetValue()));
     }
-    if ((pItem = aItemSet.GetItem(SID_ATTR_CHAR_STRIKEOUT)) != nullptr)
+    if ((pItem = pItemSet->GetItem(SID_ATTR_CHAR_STRIKEOUT)) != nullptr)
     {
         maFont.SetStrikeout(static_cast<const SvxCrossedOutItem*>(pItem)->GetStrikeout());
     }
-    if ((pItem = aItemSet.GetItem(SID_ATTR_CHAR_CASEMAP)) != nullptr)
+    if ((pItem = pItemSet->GetItem(SID_ATTR_CHAR_CASEMAP)) != nullptr)
     {
         maFont.SetCaseMap(static_cast<const SvxCaseMapItem*>(pItem)->GetCaseMap());
     }
-    if ((pItem = aItemSet.GetItem(SID_ATTR_CHAR_EMPHASISMARK)) != nullptr)
+    if ((pItem = pItemSet->GetItem(SID_ATTR_CHAR_EMPHASISMARK)) != nullptr)
     {
         maFont.SetEmphasisMark(static_cast<const SvxEmphasisMarkItem*>(pItem)->GetEmphasisMark());
     }
-    if ((pItem = aItemSet.GetItem(SID_ATTR_CHAR_COLOR)) != nullptr)
+    if ((pItem = pItemSet->GetItem(SID_ATTR_CHAR_COLOR)) != nullptr)
     {
         maFontColor = Color(static_cast<const SvxColorItem*>(pItem)->GetValue());
     }
 
     if (mpStyle->GetFamily() == SFX_STYLE_FAMILY_PARA)
     {
-        if ((pItem = aItemSet.GetItem(XATTR_FILLSTYLE)) != nullptr)
+        if ((pItem = pItemSet->GetItem(XATTR_FILLSTYLE)) != nullptr)
         {
             sal_uInt16 aFillStyle = static_cast<const XFillStyleItem*>(pItem)->GetValue();
             if (aFillStyle == drawing::FillStyle_SOLID)
             {
-                if ((pItem = aItemSet.GetItem(XATTR_FILLCOLOR)) != nullptr)
+                if ((pItem = pItemSet->GetItem(XATTR_FILLCOLOR)) != nullptr)
                 {
                     maBackgroundColor = Color(static_cast<const XFillColorItem*>(pItem)->GetColorValue());
                 }
@@ -126,7 +128,7 @@ bool CommonStylePreviewRenderer::recalculate()
         }
     }
 
-    if ((pItem = aItemSet.GetItem(SID_ATTR_CHAR_FONT)) != nullptr)
+    if ((pItem = pItemSet->GetItem(SID_ATTR_CHAR_FONT)) != nullptr)
     {
         const SvxFontItem* pFontItem = static_cast<const SvxFontItem*>(pItem);
         maFont.SetName(pFontItem->GetFamilyName());
@@ -137,7 +139,7 @@ bool CommonStylePreviewRenderer::recalculate()
         return false;
     }
 
-    if ((pItem = aItemSet.GetItem(SID_ATTR_CHAR_FONTHEIGHT)) != nullptr)
+    if ((pItem = pItemSet->GetItem(SID_ATTR_CHAR_FONTHEIGHT)) != nullptr)
     {
         const SvxFontHeightItem* pFontHeightItem = static_cast<const SvxFontHeightItem*>(pItem);
         Size aFontSize(0, pFontHeightItem->GetHeight());
diff --git a/svx/source/tbxctrls/tbcontrl.cxx b/svx/source/tbxctrls/tbcontrl.cxx
index 4bb0294f3409..81fad3205235 100644
--- a/svx/source/tbxctrls/tbcontrl.cxx
+++ b/svx/source/tbxctrls/tbcontrl.cxx
@@ -638,10 +638,13 @@ void SvxStyleBox_Impl::SetupEntry(vcl::RenderContext& rRenderContext, vcl::Windo
 
         if (pStyle )
         {
-            const SfxItemSet& aItemSet = pStyle->GetItemSet();
+            std::unique_ptr<const SfxItemSet> const pItemSet(pStyle->GetItemSetForPreview());
+            if (!pItemSet) return;
 
-            const SvxFontItem *pFontItem = static_cast< const SvxFontItem* >( aItemSet.GetItem( SID_ATTR_CHAR_FONT ) );
-            const SvxFontHeightItem *pFontHeightItem = static_cast< const SvxFontHeightItem* >( aItemSet.GetItem( SID_ATTR_CHAR_FONTHEIGHT ) );
+            const SvxFontItem * const pFontItem =
+                static_cast<const SvxFontItem*>(pItemSet->GetItem(SID_ATTR_CHAR_FONT));
+            const SvxFontHeightItem * const pFontHeightItem =
+                static_cast<const SvxFontHeightItem*>(pItemSet->GetItem(SID_ATTR_CHAR_FONTHEIGHT));
 
             if ( pFontItem && pFontHeightItem )
             {
@@ -654,43 +657,43 @@ void SvxStyleBox_Impl::SetupEntry(vcl::RenderContext& rRenderContext, vcl::Windo
                 aFont.SetStyleName(pFontItem->GetStyleName());
                 aFont.SetSize(aPixelSize);
 
-                const SfxPoolItem *pItem = aItemSet.GetItem( SID_ATTR_CHAR_WEIGHT );
+                const SfxPoolItem *pItem = pItemSet->GetItem( SID_ATTR_CHAR_WEIGHT );
                 if ( pItem )
                     aFont.SetWeight( static_cast< const SvxWeightItem* >( pItem )->GetWeight() );
 
-                pItem = aItemSet.GetItem( SID_ATTR_CHAR_POSTURE );
+                pItem = pItemSet->GetItem( SID_ATTR_CHAR_POSTURE );
                 if ( pItem )
                     aFont.SetItalic( static_cast< const SvxPostureItem* >( pItem )->GetPosture() );
 
-                pItem = aItemSet.GetItem( SID_ATTR_CHAR_CONTOUR );
+                pItem = pItemSet->GetItem( SID_ATTR_CHAR_CONTOUR );
                 if ( pItem )
                     aFont.SetOutline( static_cast< const SvxContourItem* >( pItem )->GetValue() );
 
-                pItem = aItemSet.GetItem( SID_ATTR_CHAR_SHADOWED );
+                pItem = pItemSet->GetItem( SID_ATTR_CHAR_SHADOWED );
                 if ( pItem )
                     aFont.SetShadow( static_cast< const SvxShadowedItem* >( pItem )->GetValue() );
 
-                pItem = aItemSet.GetItem( SID_ATTR_CHAR_RELIEF );
+                pItem = pItemSet->GetItem( SID_ATTR_CHAR_RELIEF );
                 if ( pItem )
                     aFont.SetRelief( static_cast< FontRelief >( static_cast< const SvxCharReliefItem* >( pItem )->GetValue() ) );
 
-                pItem = aItemSet.GetItem( SID_ATTR_CHAR_UNDERLINE );
+                pItem = pItemSet->GetItem( SID_ATTR_CHAR_UNDERLINE );
                 if ( pItem )
                     aFont.SetUnderline( static_cast< const SvxUnderlineItem* >( pItem )->GetLineStyle() );
 
-                pItem = aItemSet.GetItem( SID_ATTR_CHAR_OVERLINE );
+                pItem = pItemSet->GetItem( SID_ATTR_CHAR_OVERLINE );
                 if ( pItem )
                     aFont.SetOverline( static_cast< FontUnderline >( static_cast< const SvxOverlineItem* >( pItem )->GetValue() ) );
 
-                pItem = aItemSet.GetItem( SID_ATTR_CHAR_STRIKEOUT );
+                pItem = pItemSet->GetItem( SID_ATTR_CHAR_STRIKEOUT );
                 if ( pItem )
                     aFont.SetStrikeout( static_cast< const SvxCrossedOutItem* >( pItem )->GetStrikeout() );
 
-                pItem = aItemSet.GetItem( SID_ATTR_CHAR_CASEMAP );
+                pItem = pItemSet->GetItem( SID_ATTR_CHAR_CASEMAP );
                 if ( pItem )
                     aFont.SetCaseMap(static_cast<const SvxCaseMapItem*>(pItem)->GetCaseMap());
 
-                pItem = aItemSet.GetItem( SID_ATTR_CHAR_EMPHASISMARK );
+                pItem = pItemSet->GetItem( SID_ATTR_CHAR_EMPHASISMARK );
                 if ( pItem )
                     aFont.SetEmphasisMark( static_cast< const SvxEmphasisMarkItem* >( pItem )->GetEmphasisMark() );
 
@@ -701,14 +704,14 @@ void SvxStyleBox_Impl::SetupEntry(vcl::RenderContext& rRenderContext, vcl::Windo
 
                 rRenderContext.SetFont(aFont);
 
-                pItem = aItemSet.GetItem( SID_ATTR_CHAR_COLOR );
+                pItem = pItemSet->GetItem( SID_ATTR_CHAR_COLOR );
                 // text color, when nothing is selected
                 if ( (NULL != pItem) && bIsNotSelected)
                     aFontCol = Color( static_cast< const SvxColorItem* >( pItem )->GetValue() );
 
                 sal_uInt16 style = drawing::FillStyle_NONE;
                 // which kind of Fill style is selected
-                pItem = aItemSet.GetItem( XATTR_FILLSTYLE );
+                pItem = pItemSet->GetItem( XATTR_FILLSTYLE );
                 // only when ok and not selected
                 if ( (NULL != pItem) && bIsNotSelected)
                     style = static_cast< const XFillStyleItem* >( pItem )->GetValue();
@@ -718,7 +721,7 @@ void SvxStyleBox_Impl::SetupEntry(vcl::RenderContext& rRenderContext, vcl::Windo
                     case drawing::FillStyle_SOLID:
                     {
                         // set background color
-                        pItem = aItemSet.GetItem( XATTR_FILLCOLOR );
+                        pItem = pItemSet->GetItem( XATTR_FILLCOLOR );
                         if ( NULL != pItem )
                             aBackCol = Color( static_cast< const XFillColorItem* >( pItem )->GetColorValue() );
 
diff --git a/sw/inc/docstyle.hxx b/sw/inc/docstyle.hxx
index f874ac57c457..e50c3c01b5c2 100644
--- a/sw/inc/docstyle.hxx
+++ b/sw/inc/docstyle.hxx
@@ -61,10 +61,12 @@ class SW_DLLPUBLIC SwDocStyleSheet : public SfxStyleSheetBase
     enum FillStyleType {
         FillOnlyName,
         FillAllInfo,
-        FillPhysical
+        FillPhysical,
+        FillPreview,
     };
 
-    SAL_DLLPRIVATE bool FillStyleSheet( FillStyleType eFType );
+    SAL_DLLPRIVATE bool FillStyleSheet(FillStyleType eFType,
+            std::unique_ptr<SfxItemSet> * o_ppFlatSet = nullptr);
 
 protected:
     virtual ~SwDocStyleSheet();
@@ -99,6 +101,7 @@ public:
                                         const bool bResetIndentAttrsAtParagraphStyle = false );
 
     virtual SfxItemSet&     GetItemSet() SAL_OVERRIDE;
+    virtual std::unique_ptr<SfxItemSet> GetItemSetForPreview() override;
     /** new method for paragraph styles to merge indent attributes of applied list
      style into the given item set, if the list style indent attributes are applicable. */
     void MergeIndentAttrsOfListStyle( SfxItemSet& rSet );
diff --git a/sw/source/uibase/app/docstyle.cxx b/sw/source/uibase/app/docstyle.cxx
index 9f4dbdc0be04..0f824c8de827 100644
--- a/sw/source/uibase/app/docstyle.cxx
+++ b/sw/source/uibase/app/docstyle.cxx
@@ -1163,6 +1163,61 @@ bool   SwDocStyleSheet::SetFollow( const OUString& rStr)
     return true;
 }
 
+static
+std::unique_ptr<SfxItemSet> lcl_SwFormatToFlatItemSet(SwFormat *const pFormat)
+{
+    // note: we don't add the odd items that GetItemSet() would add
+    // because they don't seem relevant for preview
+    std::vector<SfxItemSet const*> sets;
+    sets.push_back(&pFormat->GetAttrSet());
+    while (SfxItemSet const*const pParent = sets.back()->GetParent())
+    {
+        sets.push_back(pParent);
+    }
+    // start by copying top-level parent set
+    std::unique_ptr<SfxItemSet> pRet(new SfxItemSet(*sets.back()));
+    sets.pop_back();
+    for (auto iter = sets.rbegin(); iter != sets.rend(); ++iter)
+    {   // in reverse so child overrides parent
+        pRet->Put(**iter);
+    }
+    return pRet;
+}
+
+std::unique_ptr<SfxItemSet> SwDocStyleSheet::GetItemSetForPreview()
+{
+    if (SFX_STYLE_FAMILY_PAGE == nFamily || SFX_STYLE_FAMILY_PSEUDO == nFamily)
+    {
+        SAL_WARN("sw.ui", "GetItemSetForPreview not implemented for page or number style");
+        return std::unique_ptr<SfxItemSet>();
+    }
+    if (!bPhysical)
+    {
+        // because not only this style, but also any number of its parents
+        // (or follow style) may not actually exist in the document at this
+        // time, return one "flattened" item set that contains all items from
+        // all parents.
+        std::unique_ptr<SfxItemSet> pRet;
+        FillStyleSheet(FillPreview, &pRet);
+        assert(pRet);
+        return pRet;
+    }
+    else
+    {
+        switch (nFamily)
+        {
+            case SFX_STYLE_FAMILY_CHAR:
+                return lcl_SwFormatToFlatItemSet(pCharFormat);
+            case SFX_STYLE_FAMILY_PARA:
+                return lcl_SwFormatToFlatItemSet(pColl);
+            case SFX_STYLE_FAMILY_FRAME:
+                return lcl_SwFormatToFlatItemSet(pFrameFormat);
+            default:
+                assert(false);
+        }
+    }
+}
+
 // extract ItemSet to Name and Family, Mask
 
 SfxItemSet&   SwDocStyleSheet::GetItemSet()
@@ -1703,7 +1758,8 @@ static void lcl_DeleteInfoStyles( sal_uInt16 nFamily, std::vector<void*>& rArr,
 }
 
 // determine the format
-bool SwDocStyleSheet::FillStyleSheet( FillStyleType eFType )
+bool SwDocStyleSheet::FillStyleSheet(
+    FillStyleType const eFType, std::unique_ptr<SfxItemSet> *const o_ppFlatSet)
 {
     bool bRet = false;
     sal_uInt16 nPoolId = USHRT_MAX;
@@ -1711,7 +1767,7 @@ bool SwDocStyleSheet::FillStyleSheet( FillStyleType eFType )
 
     bool bCreate = FillPhysical == eFType;
     bool bDeleteInfo = false;
-    bool bFillOnlyInfo = FillAllInfo == eFType;
+    bool bFillOnlyInfo = FillAllInfo == eFType || FillPreview == eFType;
     std::vector<void*> aDelArr;
 
     switch(nFamily)
@@ -1879,6 +1935,12 @@ bool SwDocStyleSheet::FillStyleSheet( FillStyleType eFType )
 
             if( RES_CONDTXTFMTCOLL == pFormat->Which() )
                 _nMask |= SWSTYLEBIT_CONDCOLL;
+
+            if (FillPreview == eFType)
+            {
+                assert(o_ppFlatSet);
+                *o_ppFlatSet = lcl_SwFormatToFlatItemSet(pFormat);
+            }
         }
 
         SetMask( _nMask );