starmath: m_pTree can be private

Which shows that subclasses only read it, never write it.

Change-Id: I90ea4528d4362c068ba02113b1b038a811ea32b6
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/96321
Reviewed-by: Miklos Vajna <vmiklos@collabora.com>
Tested-by: Jenkins
diff --git a/starmath/source/ooxmlexport.cxx b/starmath/source/ooxmlexport.cxx
index fff9cd7..a915596 100644
--- a/starmath/source/ooxmlexport.cxx
+++ b/starmath/source/ooxmlexport.cxx
@@ -28,7 +28,7 @@ SmOoxmlExport::SmOoxmlExport(const SmNode *const pIn, OoxmlVersion const v,

void SmOoxmlExport::ConvertFromStarMath( const ::sax_fastparser::FSHelperPtr& serializer, const sal_Int8 nAlign )
{
    if( m_pTree == nullptr )
    if( GetTree() == nullptr )
        return;
    m_pSerializer = serializer;

@@ -66,7 +66,7 @@ void SmOoxmlExport::ConvertFromStarMath( const ::sax_fastparser::FSHelperPtr& se
            m_pSerializer->singleElementNS(XML_m, XML_jc, FSNS(XML_m, XML_val), "right");
        m_pSerializer->endElementNS(XML_m, XML_oMathParaPr);
        m_pSerializer->startElementNS(XML_m, XML_oMath);
        HandleNode(m_pTree, 0);
        HandleNode(GetTree(), 0);
        m_pSerializer->endElementNS(XML_m, XML_oMath);
        m_pSerializer->endElementNS(XML_m, XML_oMathPara);
    }
@@ -74,7 +74,7 @@ void SmOoxmlExport::ConvertFromStarMath( const ::sax_fastparser::FSHelperPtr& se
    {
        m_pSerializer->startElementNS(XML_m, XML_oMath,
            FSNS(XML_xmlns, XML_m), "http://schemas.openxmlformats.org/officeDocument/2006/math");
        HandleNode( m_pTree, 0 );
        HandleNode( GetTree(), 0 );
        m_pSerializer->endElementNS( XML_m, XML_oMath );
    }
}
diff --git a/starmath/source/rtfexport.cxx b/starmath/source/rtfexport.cxx
index 87e51a3..90a13f3 100644
--- a/starmath/source/rtfexport.cxx
+++ b/starmath/source/rtfexport.cxx
@@ -24,12 +24,12 @@ SmRtfExport::SmRtfExport(const SmNode* pIn)

void SmRtfExport::ConvertFromStarMath(OStringBuffer& rBuffer, rtl_TextEncoding nEncoding)
{
    if (!m_pTree)
    if (!GetTree())
        return;
    m_pBuffer = &rBuffer;
    m_nEncoding = nEncoding;
    m_pBuffer->append("{" OOO_STRING_SVTOOLS_RTF_IGNORE LO_STRING_SVTOOLS_RTF_MOMATH " ");
    HandleNode(m_pTree, 0);
    HandleNode(GetTree(), 0);
    m_pBuffer->append("}"); // moMath
}

diff --git a/starmath/source/wordexportbase.hxx b/starmath/source/wordexportbase.hxx
index 4f191df..af66167 100644
--- a/starmath/source/wordexportbase.hxx
+++ b/starmath/source/wordexportbase.hxx
@@ -49,6 +49,9 @@ protected:
    virtual void HandleBrace(const SmBraceNode* pNode, int nLevel) = 0;
    virtual void HandleVerticalBrace(const SmVerticalBraceNode* pNode, int nLevel) = 0;
    virtual void HandleBlank() = 0;
    const SmNode* GetTree() const { return m_pTree; }

private:
    const SmNode* const m_pTree;
};