XmlFilterAdaptor: use the fastparser API when possible

part of the process of making SvXMLImport fastparser-only

Which uncovered several bugs because I end up stacking fast and
slow parsers, not once, but twice.

Specifically, we have a problem here with default namespaces e.g.

    <math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
    <semantics><mrow><mstyle mathsize="12pt">

where going from slow- to fast- parser loses this information,
because there is no way to represent this in the fastparser world,
so we end up with nastiness when we transition back to slow-parser,
and then back-again to fast-parser.

So I fixed a couple of places XMLEmbeddedObjectImportContext
and in SvXMLLegacyToFastDocHandler, and then worked around some of
it by introducing an new XImporter2 interface so I could strip out
out one of the slowparser -> fastparser transitions.

Change-Id: I491487b99271898da50dc999d3b9b9c39cbd97fd
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/104514
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

9 files changed, 354 insertions, 36 deletions

diff --git a/filter/Library_xmlfa.mk b/filter/Library_xmlfa.mk
index 425cebc691f1..147bed21d7c6 100644
--- a/filter/Library_xmlfa.mk
+++ b/filter/Library_xmlfa.mk
@@ -32,6 +32,7 @@ $(eval $(call gb_Library_use_libraries,xmlfa,\
 	sal \
 	tl \
 	utl \
+	xo \
 ))
 
 $(eval $(call gb_Library_add_exception_objects,xmlfa,\
diff --git a/filter/source/odfflatxml/OdfFlatXml.cxx b/filter/source/odfflatxml/OdfFlatXml.cxx
index 4894887ce140..23106bf1daf2 100644
--- a/filter/source/odfflatxml/OdfFlatXml.cxx
+++ b/filter/source/odfflatxml/OdfFlatXml.cxx
@@ -24,6 +24,7 @@
 #include <com/sun/star/beans/PropertyValue.hpp>
 
 #include <com/sun/star/xml/XImportFilter.hpp>
+#include <com/sun/star/xml/XImportFilter2.hpp>
 #include <com/sun/star/xml/XExportFilter.hpp>
 #include <com/sun/star/xml/sax/Parser.hpp>
 #include <com/sun/star/xml/sax/InputSource.hpp>
@@ -55,7 +56,7 @@ namespace filter::odfflatxml {
          * OdfFlatXml export and imports ODF flat XML documents by plugging a pass-through
          * filter implementation into XmlFilterAdaptor.
          */
-        class OdfFlatXml : public WeakImplHelper<XImportFilter,
+        class OdfFlatXml : public WeakImplHelper<XImportFilter, XImportFilter2,
                                                   XExportFilter, DocumentHandlerAdapter, css::lang::XServiceInfo>
         {
         private:
@@ -74,6 +75,12 @@ namespace filter::odfflatxml {
                      const Reference< XDocumentHandler >& docHandler,
                      const Sequence< OUString >& userData) override;
 
+            // XImportFilter2
+            virtual sal_Bool SAL_CALL
+            importer(const Sequence< PropertyValue >& sourceData,
+                     const Reference< XFastParser >& fastParser,
+                     const Sequence< OUString >& userData) override;
+
             // XExportFilter
             virtual sal_Bool SAL_CALL
             exporter(
@@ -126,25 +133,76 @@ OdfFlatXml::importer(
     if (!inputStream.is())
         return false;
 
-    Reference<XParser> saxParser = Parser::create(m_xContext);
-
     InputSource inputSource;
     inputSource.sSystemId = url;
     inputSource.sPublicId = url;
     inputSource.aInputStream = inputStream;
-    css::uno::Reference< css::xml::sax::XFastParser > xFastParser = dynamic_cast<
-                            css::xml::sax::XFastParser* >( docHandler.get() );
-    saxParser->setDocumentHandler(docHandler);
     try
     {
         css::uno::Reference< css::io::XSeekable > xSeekable( inputStream, css::uno::UNO_QUERY );
         if ( xSeekable.is() )
             xSeekable->seek( 0 );
 
+        css::uno::Reference< css::xml::sax::XFastParser > xFastParser (docHandler, UNO_QUERY );
         if( xFastParser.is() )
             xFastParser->parseStream( inputSource );
         else
+        {
+            Reference<XParser> saxParser = Parser::create(m_xContext);
+            saxParser->setDocumentHandler(docHandler);
             saxParser->parseStream(inputSource);
+        }
+    }
+    catch (const Exception &)
+    {
+        TOOLS_WARN_EXCEPTION("filter.odfflatxml", "");
+        return false;
+    }
+    catch (const std::exception &exc)
+    {
+        SAL_WARN("filter.odfflatxml", exc.what());
+        return false;
+    }
+    return true;
+}
+
+sal_Bool
+OdfFlatXml::importer(
+                     const Sequence< PropertyValue >& sourceData,
+                     const Reference< XFastParser >& xFastParser,
+                     const Sequence< OUString >& /* userData */)
+{
+    // Read InputStream to read from and a URL used for the system id
+    // of the InputSource we create from the given sourceData sequence
+    Reference<XInputStream> inputStream;
+    OUString paramName;
+    OUString url;
+
+    sal_Int32 paramCount = sourceData.getLength();
+    for (sal_Int32 paramIdx = 0; paramIdx < paramCount; paramIdx++)
+        {
+            paramName = sourceData[paramIdx].Name;
+            if ( paramName == "InputStream" )
+                sourceData[paramIdx].Value >>= inputStream;
+            else if ( paramName == "URL" )
+                sourceData[paramIdx].Value >>= url;
+        }
+
+    OSL_ASSERT(inputStream.is());
+    if (!inputStream.is())
+        return false;
+
+    InputSource inputSource;
+    inputSource.sSystemId = url;
+    inputSource.sPublicId = url;
+    inputSource.aInputStream = inputStream;
+    try
+    {
+        css::uno::Reference< css::io::XSeekable > xSeekable( inputStream, css::uno::UNO_QUERY );
+        if ( xSeekable.is() )
+            xSeekable->seek( 0 );
+
+        xFastParser->parseStream( inputSource );
     }
     catch (const Exception &)
     {
diff --git a/filter/source/xmlfilteradaptor/XmlFilterAdaptor.cxx b/filter/source/xmlfilteradaptor/XmlFilterAdaptor.cxx
index 452eaebaf1c8..dfebcced36db 100644
--- a/filter/source/xmlfilteradaptor/XmlFilterAdaptor.cxx
+++ b/filter/source/xmlfilteradaptor/XmlFilterAdaptor.cxx
@@ -24,8 +24,9 @@
 #include <tools/urlobj.hxx>
 #include "XmlFilterAdaptor.hxx"
 #include <com/sun/star/io/XActiveDataSource.hpp>
-#include <com/sun/star/xml/sax/XDocumentHandler.hpp>
+#include <com/sun/star/xml/sax/XFastDocumentHandler.hpp>
 #include <com/sun/star/xml/XImportFilter.hpp>
+#include <com/sun/star/xml/XImportFilter2.hpp>
 #include <com/sun/star/xml/XExportFilter.hpp>
 #include <com/sun/star/task/XStatusIndicator.hpp>
 #include <com/sun/star/style/XStyleFamiliesSupplier.hpp>
@@ -42,6 +43,7 @@
 #include <comphelper/scopeguard.hxx>
 #include <cppuhelper/supportsservice.hxx>
 #include <unotools/pathoptions.hxx>
+#include <xmloff/xmlimp.hxx>
 
 using namespace comphelper;
 using namespace com::sun::star::uno;
@@ -107,12 +109,13 @@ bool XmlFilterAdaptor::importImpl( const Sequence< css::beans::PropertyValue >&
     aAnys[0] <<= xInfoSet;
 
 
-    Reference < XDocumentHandler > xHandler( mxContext->getServiceManager()->createInstanceWithArgumentsAndContext( sXMLImportService, aAnys, mxContext ), UNO_QUERY );
-    if (!xHandler.is()) {
-        SAL_WARN("filter.xmlfa", "XmlFilterAdaptor: unable to create service " << sXMLImportService);
-        return false;
-    }
+    // the underlying SvXMLImport implements XFastParser, XImporter, XFastDocumentHandler
+    Reference < XInterface > xFilter = mxContext->getServiceManager()->createInstanceWithArgumentsAndContext( sXMLImportService, aAnys, mxContext );
+    assert(xFilter);
+    Reference < XFastDocumentHandler > xHandler( xFilter, UNO_QUERY );
+    assert(xHandler);
     Reference < XImporter > xImporter( xHandler, UNO_QUERY );
+    assert(xImporter);
     xImporter->setTargetDocument ( mxDoc );
 
     if (xStatusIndicator.is()){
@@ -122,7 +125,8 @@ bool XmlFilterAdaptor::importImpl( const Sequence< css::beans::PropertyValue >&
 
     // Creating a ConverterBridge instance
 
-    Reference< XInterface > xConvBridge(mxContext->getServiceManager()->createInstanceWithContext(udConvertClass, mxContext), UNO_QUERY);
+    Reference< XInterface > xConvBridge(
+        mxContext->getServiceManager()->createInstanceWithContext(udConvertClass, mxContext), UNO_QUERY);
     if (!xConvBridge.is()) {
         SAL_WARN("filter.xmlfa", "XmlFilterAdaptor: unable to create service " << udConvertClass);
         return false;
@@ -130,7 +134,8 @@ bool XmlFilterAdaptor::importImpl( const Sequence< css::beans::PropertyValue >&
     if (xStatusIndicator.is())
         xStatusIndicator->setValue(nSteps++);
 
-    Reference< XImportFilter > xConverter( xConvBridge, UNO_QUERY );
+    Reference< XImportFilter > xConverter1( xConvBridge, UNO_QUERY );
+    Reference< XImportFilter2 > xConverter2( xConvBridge, UNO_QUERY );
 
     // prevent unnecessary broadcasting when loading
     Reference< XModel > xModel( mxDoc, UNO_QUERY );
@@ -170,10 +175,24 @@ bool XmlFilterAdaptor::importImpl( const Sequence< css::beans::PropertyValue >&
     // Calling Filtering Component
 
     try {
-        if (!xConverter->importer(aDescriptor,xHandler,msUserData)) {
-            if (xStatusIndicator.is())
-                   xStatusIndicator->end();
-            return false;
+        auto pImport = dynamic_cast<SvXMLImport*>(xHandler.get());
+        assert(pImport);
+        if (xConverter2)
+        {
+            if (!xConverter2->importer(aDescriptor,pImport,msUserData)) {
+                if (xStatusIndicator.is())
+                    xStatusIndicator->end();
+                return false;
+            }
+        }
+        else
+        {
+            Reference<XDocumentHandler> xDocHandler = new SvXMLLegacyToFastDocHandler(pImport);
+            if (!xConverter1->importer(aDescriptor,xDocHandler,msUserData)) {
+                if (xStatusIndicator.is())
+                    xStatusIndicator->end();
+                return false;
+            }
         }
     }
     catch( const Exception& )
diff --git a/filter/source/xsltfilter/XSLTFilter.cxx b/filter/source/xsltfilter/XSLTFilter.cxx
index 207d44e63685..9ed506d6c5ab 100644
--- a/filter/source/xsltfilter/XSLTFilter.cxx
+++ b/filter/source/xsltfilter/XSLTFilter.cxx
@@ -47,6 +47,7 @@
 #include <com/sun/star/xml/sax/XFastParser.hpp>
 #include <com/sun/star/xml/sax/Writer.hpp>
 #include <com/sun/star/xml/XImportFilter.hpp>
+#include <com/sun/star/xml/XImportFilter2.hpp>
 #include <com/sun/star/xml/XExportFilter.hpp>
 
 #include <com/sun/star/util/theMacroExpander.hpp>
@@ -97,7 +98,7 @@ namespace XSLT
      * supporting service from an extension for a specific filter; the
      * service must support com.sun.star.xml.xslt.XSLT2Transformer.
      */
-    class XSLTFilter : public WeakImplHelper<XImportFilter, XExportFilter,
+    class XSLTFilter : public WeakImplHelper<XImportFilter, XImportFilter2, XExportFilter,
             XStreamListener, ExtendedDocumentHandlerAdapter, XServiceInfo>
     {
     private:
@@ -151,6 +152,12 @@ namespace XSLT
                 XDocumentHandler>& xHandler,
                 const Sequence<OUString>& msUserData) override;
 
+        // XImportFilter2
+        virtual sal_Bool SAL_CALL
+        importer(const Sequence<PropertyValue>& aSourceData, const css::uno::Reference<
+                XFastParser>& xFastParser,
+                const Sequence<OUString>& msUserData) override;
+
         // XExportFilter
         virtual sal_Bool SAL_CALL
         exporter(const Sequence<PropertyValue>& aSourceData, const Sequence<
@@ -314,10 +321,6 @@ namespace XSLT
         if (!xInputStream.is())
             return false;
 
-        // create SAX parser that will read the document file
-        // and provide events to xHandler passed to this call
-        css::uno::Reference<XParser> xSaxParser = Parser::create(m_xContext);
-
         // create transformer
         Sequence<Any> args(3);
         NamedValue nv;
@@ -366,8 +369,6 @@ namespace XSLT
                         aInput.sPublicId = aURL;
                         aInput.aInputStream = pipein;
 
-                        // set doc handler
-                        xSaxParser->setDocumentHandler(xHandler);
                         css::uno::Reference< css::xml::sax::XFastParser > xFastParser = dynamic_cast<
                             css::xml::sax::XFastParser* >( xHandler.get() );
 
@@ -404,7 +405,14 @@ namespace XSLT
                                 if( xFastParser.is() )
                                     xFastParser->parseStream( aInput );
                                 else
+                                {
+                                    // create SAX parser that will read the document file
+                                    // and provide events to xHandler passed to this call
+                                    css::uno::Reference<XParser> xSaxParser = Parser::create(m_xContext);
+                                    // set doc handler
+                                    xSaxParser->setDocumentHandler(xHandler);
                                     xSaxParser->parseStream( aInput );
+                                }
                         }
                         m_tcontrol->terminate();
                         return !m_bError;
@@ -423,6 +431,134 @@ namespace XSLT
     }
 
     sal_Bool
+    XSLTFilter::importer(const Sequence<PropertyValue>& aSourceData,
+            const css::uno::Reference<XFastParser>& xFastParser, const Sequence<
+                    OUString>& msUserData)
+    {
+        if (msUserData.getLength() < 5)
+            return false;
+
+        OUString udStyleSheet = rel2abs(msUserData[4]);
+
+        // get information from media descriptor
+        // the input stream that represents the imported file
+        // is most important here since we need to supply it to
+        // the sax parser that drives the supplied document handler
+        sal_Int32 nLength = aSourceData.getLength();
+        OUString aName, aURL;
+        css::uno::Reference<XInputStream> xInputStream;
+        css::uno::Reference<XInteractionHandler> xInterActionHandler;
+        for (sal_Int32 i = 0; i < nLength; i++)
+            {
+                aName = aSourceData[i].Name;
+                Any value = aSourceData[i].Value;
+                if ( aName == "InputStream" )
+                    value >>= xInputStream;
+                else if ( aName == "URL" )
+                    value >>= aURL;
+                else if ( aName == "InteractionHandler" )
+                    value >>= xInterActionHandler;
+            }
+        OSL_ASSERT(xInputStream.is());
+        if (!xInputStream.is())
+            return false;
+
+        // create transformer
+        Sequence<Any> args(3);
+        NamedValue nv;
+
+        nv.Name = "StylesheetURL";
+        nv.Value <<= expandUrl(udStyleSheet);
+        args[0] <<= nv;
+        nv.Name = "SourceURL";
+        nv.Value <<= aURL;
+        args[1] <<= nv;
+        nv.Name = "SourceBaseURL";
+        nv.Value <<= INetURLObject(aURL).getBase();
+        args[2] <<= nv;
+
+        m_tcontrol = impl_createTransformer(msUserData[1], args);
+
+        assert(xFastParser.is());
+        OSL_ASSERT(xInputStream.is());
+        OSL_ASSERT(m_tcontrol.is());
+        if (xFastParser.is() && xInputStream.is() && m_tcontrol.is())
+            {
+                try
+                    {
+                        css::uno::Reference<css::io::XSeekable> xSeek(xInputStream, UNO_QUERY);
+                        if (xSeek.is())
+                            xSeek->seek(0);
+
+                        // we want to be notified when the processing is done...
+                        m_tcontrol->addListener(css::uno::Reference<XStreamListener> (
+                                this));
+
+                        // connect input to transformer
+                        m_tcontrol->setInputStream(xInputStream);
+
+                        // create pipe
+                        css::uno::Reference<XOutputStream> pipeout =
+                                        Pipe::create(m_xContext);
+                        css::uno::Reference<XInputStream> pipein(pipeout, UNO_QUERY);
+
+                        //connect transformer to pipe
+                        m_tcontrol->setOutputStream(pipeout);
+
+                        // connect pipe to sax parser
+                        InputSource aInput;
+                        aInput.sSystemId = aURL;
+                        aInput.sPublicId = aURL;
+                        aInput.aInputStream = pipein;
+
+                        // transform
+                        m_tcontrol->start();
+                        TimeValue timeout = { TRANSFORMATION_TIMEOUT_SEC, 0};
+                        osl::Condition::Result result(m_cTransformed.wait(&timeout));
+                        while (osl::Condition::result_timeout == result) {
+                                if (xInterActionHandler.is()) {
+                                        Sequence<Any> excArgs(0);
+                                        css::ucb::InteractiveAugmentedIOException exc(
+                                                "Timeout!",
+                                                static_cast< OWeakObject * >( this ),
+                                                InteractionClassification_ERROR,
+                                                css::ucb::IOErrorCode_GENERAL,
+                                                 excArgs);
+                                        Any r;
+                                        r <<= exc;
+                                        ::comphelper::OInteractionRequest* pRequest = new ::comphelper::OInteractionRequest(r);
+                                        css::uno::Reference< XInteractionRequest > xRequest(pRequest);
+                                        ::comphelper::OInteractionRetry* pRetry = new ::comphelper::OInteractionRetry;
+                                        ::comphelper::OInteractionAbort* pAbort = new ::comphelper::OInteractionAbort;
+                                        pRequest->addContinuation(pRetry);
+                                        pRequest->addContinuation(pAbort);
+                                        xInterActionHandler->handle(xRequest);
+                                        if (pAbort->wasSelected()) {
+                                                m_bError = true;
+                                                m_cTransformed.set();
+                                        }
+                                }
+                                result = m_cTransformed.wait(&timeout);
+                        };
+                        if (!m_bError)
+                            xFastParser->parseStream( aInput );
+                        m_tcontrol->terminate();
+                        return !m_bError;
+                    }
+                catch( const Exception& )
+                    {
+                        // something went wrong
+                        TOOLS_WARN_EXCEPTION("filter.xslt", "");
+                        return false;
+                    }
+            }
+        else
+            {
+                return false;
+            }
+    }
+
+    sal_Bool
     XSLTFilter::exporter(const Sequence<PropertyValue>& aSourceData,
             const Sequence<OUString>& msUserData)
     {
diff --git a/include/xmloff/xmlimp.hxx b/include/xmloff/xmlimp.hxx
index b73f565f5837..3e3a9cf89ad1 100644
--- a/include/xmloff/xmlimp.hxx
+++ b/include/xmloff/xmlimp.hxx
@@ -151,6 +151,7 @@ class XMLOFF_DLLPUBLIC SvXMLLegacyToFastDocHandler final : public ::cppu::WeakIm
 private:
     rtl::Reference< SvXMLImport > mrImport;
     rtl::Reference< sax_fastparser::FastAttributeList > mxFastAttributes;
+    std::stack<sal_uInt16> maDefaultNamespaces;
 
 public:
     SvXMLLegacyToFastDocHandler( const rtl::Reference< SvXMLImport > & rImport );
diff --git a/offapi/UnoApi_offapi.mk b/offapi/UnoApi_offapi.mk
index 0eaefbcca348..8d6e21d00a9b 100644
--- a/offapi/UnoApi_offapi.mk
+++ b/offapi/UnoApi_offapi.mk
@@ -4245,6 +4245,7 @@ $(eval $(call gb_UnoApi_add_idlfiles,offapi,com/sun/star/xml,\
 	FastAttribute \
 	XExportFilter \
 	XImportFilter \
+	XImportFilter2 \
 ))
 $(eval $(call gb_UnoApi_add_idlfiles,offapi,com/sun/star/xml/crypto,\
 	CipherID \
diff --git a/offapi/com/sun/star/xml/XImportFilter2.idl b/offapi/com/sun/star/xml/XImportFilter2.idl
new file mode 100644
index 000000000000..9c3f6bd56f7d
--- /dev/null
+++ b/offapi/com/sun/star/xml/XImportFilter2.idl
@@ -0,0 +1,71 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ *   Licensed to the Apache Software Foundation (ASF) under one or more
+ *   contributor license agreements. See the NOTICE file distributed
+ *   with this work for additional information regarding copyright
+ *   ownership. The ASF licenses this file to you under the Apache
+ *   License, Version 2.0 (the "License"); you may not use this file
+ *   except in compliance with the License. You may obtain a copy of
+ *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+#ifndef _COM_SUN_STAR_XML_XIMPORTFILTER2_IDL__
+#define _COM_SUN_STAR_XML_XIMPORTFILTER2_IDL__
+
+#include <com/sun/star/uno/RuntimeException.idl>
+#include <com/sun/star/uno/XInterface.idl>
+#include <com/sun/star/beans/PropertyValue.idl>
+#include <com/sun/star/xml/sax/XFastParser.idl>
+#include <com/sun/star/lang/IllegalArgumentException.idl>
+
+
+module com { module sun { module star { module xml {
+
+
+
+/** interface to implement for an XML-based import filter.
+    Enhanced vs XImportFilter to take a XFastDocumentHandler.
+
+    @since LibreOffice 7.1
+ */
+interface XImportFilter2: com::sun::star::uno::XInterface
+{
+     /** performs the import.
+
+         <p>The source data (location indicated by <var>aSourceData</var>),
+            and the XML representation of the document must be generated by calls
+            to xocHandler (???) methods.
+
+      @param aSourceData
+          com::sun::star::document::MediaDescriptor
+          which defines the data source
+
+      @param msUserData
+          Sequence of strings which contains the user data defined in the
+          TypeDetection.xml
+
+      @param xFastParser
+          the fast parser for the XML document, i.e. an SvXMLImport subclass
+
+      @returns
+          `TRUE` if import process is successful
+     */
+    boolean importer(
+             [in] sequence< com::sun::star::beans::PropertyValue > aSourceData,
+             [in] com::sun::star::xml::sax::XFastParser xFastParser,
+             [in] sequence< string > msUserData )
+        raises( com::sun::star::lang::IllegalArgumentException );
+};
+
+}; }; }; };
+#endif
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/xmloff/source/core/XMLEmbeddedObjectImportContext.cxx b/xmloff/source/core/XMLEmbeddedObjectImportContext.cxx
index 36bb7e4d8e7e..c238bbf9de4b 100644
--- a/xmloff/source/core/XMLEmbeddedObjectImportContext.cxx
+++ b/xmloff/source/core/XMLEmbeddedObjectImportContext.cxx
@@ -260,7 +260,7 @@ void XMLEmbeddedObjectImportContext::StartElement(
     sal_uInt16 nPos = rNamespaceMap.GetFirstKey();
     while( USHRT_MAX != nPos )
     {
-        OUString aAttrName( rNamespaceMap.GetAttrNameByKey( nPos ) );
+        OUString aAttrName = "xmlns:" + rNamespaceMap.GetPrefixByKey( nPos );
         if( xAttrList->getValueByName( aAttrName ).isEmpty() )
         {
             pAttrList->AddAttribute( aAttrName,
diff --git a/xmloff/source/core/xmlimp.cxx b/xmloff/source/core/xmlimp.cxx
index e56448adabd2..5cddf60205e9 100644
--- a/xmloff/source/core/xmlimp.cxx
+++ b/xmloff/source/core/xmlimp.cxx
@@ -2248,6 +2248,9 @@ void SAL_CALL SvXMLLegacyToFastDocHandler::endDocument()
 void SAL_CALL SvXMLLegacyToFastDocHandler::startElement( const OUString& rName,
                         const uno::Reference< xml::sax::XAttributeList >& xAttrList )
 {
+    sal_uInt16 nDefaultNamespace = XML_NAMESPACE_UNKNOWN;
+    if (!maDefaultNamespaces.empty())
+        nDefaultNamespace = maDefaultNamespaces.top();
     mrImport->processNSAttributes(xAttrList);
     OUString aLocalName;
     sal_uInt16 nPrefix = mrImport->mpNamespaceMap->GetKeyByAttrName( rName, &aLocalName );
@@ -2257,30 +2260,57 @@ void SAL_CALL SvXMLLegacyToFastDocHandler::startElement( const OUString& rName,
     sal_Int16 nAttrCount = xAttrList.is() ? xAttrList->getLength() : 0;
     for( sal_Int16 i=0; i < nAttrCount; i++ )
     {
-        OUString aLocalAttrName;
-        OUString aNamespace;
         const OUString& rAttrName = xAttrList->getNameByIndex( i );
         const OUString& rAttrValue = xAttrList->getValueByIndex( i );
-        // don't add unknown namespaces to the map
-        sal_uInt16 const nAttrPrefix = mrImport->mpNamespaceMap->GetKeyByQName(
-                rAttrName, nullptr, &aLocalAttrName, &aNamespace, SvXMLNamespaceMap::QNameMode::AttrValue);
-        if( XML_NAMESPACE_XMLNS != nAttrPrefix )
+        if (rAttrName == "xmlns")
         {
-            auto const nToken = SvXMLImport::getTokenFromName(aLocalAttrName);
-            if (XML_NAMESPACE_UNKNOWN == nAttrPrefix || nToken == xmloff::XML_TOKEN_INVALID)
+            sal_uInt16 nNamespaceKey = mrImport->mpNamespaceMap->GetKeyByName(rAttrValue);
+            if (nNamespaceKey != XML_NAMESPACE_UNKNOWN)
             {
-                mxFastAttributes->addUnknown(aNamespace,
+                nDefaultNamespace = nNamespaceKey;
+                continue;
+            }
+            assert(false && "unknown namespace");
+        }
+        else if (rAttrName.indexOf(":") == -1 && nDefaultNamespace != XML_NAMESPACE_UNKNOWN)
+        {
+            auto const nToken = SvXMLImport::getTokenFromName(rAttrName);
+            if (nToken == xmloff::XML_TOKEN_INVALID)
+            {
+                mxFastAttributes->addUnknown(mrImport->mpNamespaceMap->GetNameByKey(nDefaultNamespace),
                     OUStringToOString(rAttrName, RTL_TEXTENCODING_UTF8),
                     OUStringToOString(rAttrValue, RTL_TEXTENCODING_UTF8));
             }
             else
             {
-                sal_Int32 const nAttr = NAMESPACE_TOKEN(nAttrPrefix) | nToken;
+                sal_Int32 const nAttr = NAMESPACE_TOKEN(nDefaultNamespace) | nToken;
                 mxFastAttributes->add(nAttr, OUStringToOString(rAttrValue, RTL_TEXTENCODING_UTF8).getStr());
             }
+            continue;
+        }
+
+        OUString aLocalAttrName;
+        OUString aNamespace;
+        // don't add unknown namespaces to the map
+        sal_uInt16 const nAttrPrefix = mrImport->mpNamespaceMap->GetKeyByQName(
+                rAttrName, nullptr, &aLocalAttrName, &aNamespace, SvXMLNamespaceMap::QNameMode::AttrValue);
+        if( XML_NAMESPACE_XMLNS == nAttrPrefix )
+            continue; // ignore
+        auto const nToken = SvXMLImport::getTokenFromName(aLocalAttrName);
+        if (XML_NAMESPACE_UNKNOWN == nAttrPrefix || nToken == xmloff::XML_TOKEN_INVALID)
+        {
+            mxFastAttributes->addUnknown(aNamespace,
+                OUStringToOString(rAttrName, RTL_TEXTENCODING_UTF8),
+                OUStringToOString(rAttrValue, RTL_TEXTENCODING_UTF8));
+        }
+        else
+        {
+            sal_Int32 const nAttr = NAMESPACE_TOKEN(nAttrPrefix) | nToken;
+            mxFastAttributes->add(nAttr, OUStringToOString(rAttrValue, RTL_TEXTENCODING_UTF8).getStr());
         }
     }
     mrImport->startFastElement( mnElement, mxFastAttributes.get() );
+    maDefaultNamespaces.push(nDefaultNamespace);
 }
 
 void SAL_CALL SvXMLLegacyToFastDocHandler::endElement( const OUString& rName )
@@ -2289,6 +2319,7 @@ void SAL_CALL SvXMLLegacyToFastDocHandler::endElement( const OUString& rName )
     sal_uInt16 nPrefix = mrImport->mpNamespaceMap->GetKeyByAttrName( rName, &aLocalName );
     sal_Int32 mnElement = NAMESPACE_TOKEN( nPrefix ) | SvXMLImport::getTokenFromName(aLocalName);
     mrImport->endFastElement( mnElement );
+    maDefaultNamespaces.pop();
 }
 
 void SAL_CALL SvXMLLegacyToFastDocHandler::characters( const OUString& aChars )