dp_descriptioninfoset.cxx

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/* -*- 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 .
 */

#include <sal/config.h>

#include <string_view>

#include <dp_descriptioninfoset.hxx>

#include <dp_resource.h>

#include <comphelper/sequence.hxx>
#include <comphelper/processfactory.hxx>
#include <comphelper/propertysequence.hxx>
#include <optional>
#include <com/sun/star/configuration/theDefaultProvider.hpp>
#include <com/sun/star/container/XNameAccess.hpp>
#include <com/sun/star/deployment/DeploymentException.hpp>
#include <com/sun/star/beans/XPropertySet.hpp>
#include <com/sun/star/io/SequenceInputStream.hpp>
#include <com/sun/star/lang/XMultiComponentFactory.hpp>
#include <com/sun/star/lang/WrappedTargetRuntimeException.hpp>
#include <com/sun/star/task/XInteractionHandler.hpp>
#include <com/sun/star/ucb/XCommandEnvironment.hpp>
#include <com/sun/star/ucb/XProgressHandler.hpp>
#include <com/sun/star/uno/Reference.hxx>
#include <com/sun/star/uno/RuntimeException.hpp>
#include <com/sun/star/uno/Sequence.hxx>
#include <com/sun/star/uno/XInterface.hpp>
#include <com/sun/star/xml/dom/DOMException.hpp>
#include <com/sun/star/xml/dom/XNode.hpp>
#include <com/sun/star/xml/dom/XNodeList.hpp>
#include <com/sun/star/xml/dom/DocumentBuilder.hpp>
#include <com/sun/star/xml/xpath/XPathAPI.hpp>
#include <com/sun/star/xml/xpath/XPathException.hpp>
#include <com/sun/star/ucb/InteractiveIOException.hpp>
#include <cppuhelper/implbase.hxx>
#include <cppuhelper/weak.hxx>
#include <cppuhelper/exc_hlp.hxx>
#include <rtl/ustring.hxx>
#include <sal/types.h>
#include <ucbhelper/content.hxx>
#include <o3tl/string_view.hxx>

namespace {

using css::uno::Reference;

class EmptyNodeList:
    public cppu::WeakImplHelper<css::xml::dom::XNodeList>
{
public:
    EmptyNodeList();

    EmptyNodeList(const EmptyNodeList&) = delete;
    const EmptyNodeList& operator=(const EmptyNodeList&) = delete;

    virtual ::sal_Int32 SAL_CALL getLength() override;

    virtual css::uno::Reference< css::xml::dom::XNode > SAL_CALL
    item(::sal_Int32 index) override;
};

EmptyNodeList::EmptyNodeList() {}

::sal_Int32 EmptyNodeList::getLength() {
    return 0;
}

css::uno::Reference< css::xml::dom::XNode > EmptyNodeList::item(::sal_Int32)
{
    throw css::uno::RuntimeException("bad EmptyNodeList com.sun.star.xml.dom.XNodeList.item call",
        static_cast< ::cppu::OWeakObject * >(this));
}

OUString getNodeValue(
    css::uno::Reference< css::xml::dom::XNode > const & node)
{
    OSL_ASSERT(node.is());
    try {
        return node->getNodeValue();
    } catch (const css::xml::dom::DOMException & e) {
        css::uno::Any anyEx = cppu::getCaughtException();
        throw css::lang::WrappedTargetRuntimeException(
            "com.sun.star.xml.dom.DOMException: " + e.Message,
            nullptr, anyEx );
    }
}

class ExtensionDescription
{
public:
    ExtensionDescription(
        const css::uno::Reference<css::uno::XComponentContext>& xContext,
        std::u16string_view installDir,
        const css::uno::Reference< css::ucb::XCommandEnvironment >& xCmdEnv);

    const css::uno::Reference<css::xml::dom::XNode>& getRootElement() const
    {
        return m_xRoot;
    }

private:
    css::uno::Reference<css::xml::dom::XNode> m_xRoot;
};

class NoDescriptionException
{
};

class FileDoesNotExistFilter
    : public ::cppu::WeakImplHelper< css::ucb::XCommandEnvironment,
                                      css::task::XInteractionHandler >

{
    bool m_bExist;
    css::uno::Reference< css::ucb::XCommandEnvironment > m_xCommandEnv;

public:
    explicit FileDoesNotExistFilter(
        const css::uno::Reference< css::ucb::XCommandEnvironment >& xCmdEnv);

    bool exist() { return m_bExist;}
    // XCommandEnvironment
    virtual css::uno::Reference<css::task::XInteractionHandler > SAL_CALL
    getInteractionHandler() override;
    virtual css::uno::Reference<css::ucb::XProgressHandler >
    SAL_CALL getProgressHandler() override;

    // XInteractionHandler
    virtual void SAL_CALL handle(
        css::uno::Reference<css::task::XInteractionRequest > const & xRequest ) override;
};

ExtensionDescription::ExtensionDescription(
    const Reference<css::uno::XComponentContext>& xContext,
    std::u16string_view installDir,
    const Reference< css::ucb::XCommandEnvironment >& xCmdEnv)
{
    try {
        //may throw css::ucb::ContentCreationException
        //If there is no description.xml then ucb will start an interaction which
        //brings up a dialog.We want to prevent this. Therefore we wrap the xCmdEnv
        //and filter the respective exception out.
        OUString sDescriptionUri(OUString::Concat(installDir) + "/description.xml");
        Reference<css::ucb::XCommandEnvironment> xFilter = new FileDoesNotExistFilter(xCmdEnv);
        ::ucbhelper::Content descContent(sDescriptionUri, xFilter, xContext);

        //throws a css::uno::Exception if the file is not available
        Reference<css::io::XInputStream> xIn;
        try
        {   //throws com.sun.star.ucb.InteractiveIOException
            xIn = descContent.openStream();
        }
        catch ( const css::uno::Exception& )
        {
            if ( ! static_cast<FileDoesNotExistFilter*>(xFilter.get())->exist())
                throw NoDescriptionException();
            throw;
        }
        if (!xIn.is())
        {
            throw css::uno::Exception(
                "Could not get XInputStream for description.xml of extension " +
                sDescriptionUri, nullptr);
        }

        //get root node of description.xml
        Reference<css::xml::dom::XDocumentBuilder> xDocBuilder(
            css::xml::dom::DocumentBuilder::create(xContext) );

        if (!xDocBuilder->isNamespaceAware())
        {
            throw css::uno::Exception(
                "Service com.sun.star.xml.dom.DocumentBuilder is not namespace aware.", nullptr);
        }

        Reference<css::xml::dom::XDocument> xDoc = xDocBuilder->parse(xIn);
        if (!xDoc.is())
        {
            throw css::uno::Exception(sDescriptionUri + " contains data which cannot be parsed. ", nullptr);
        }

        //check for proper root element and namespace
        Reference<css::xml::dom::XElement> xRoot = xDoc->getDocumentElement();
        if (!xRoot.is())
        {
            throw css::uno::Exception(
                sDescriptionUri + " contains no root element.", nullptr);
        }

        if ( xRoot->getTagName() != "description")
        {
            throw css::uno::Exception(
                sDescriptionUri + " does not contain the root element <description>.", nullptr);
        }

        m_xRoot.set(xRoot, css::uno::UNO_QUERY_THROW);
        OUString nsDescription = xRoot->getNamespaceURI();

        //check if this namespace is supported
        if ( nsDescription != "http://openoffice.org/extensions/description/2006")
        {
            throw css::uno::Exception(sDescriptionUri + " contains a root element with an unsupported namespace. ", nullptr);
        }
    } catch (const css::uno::RuntimeException &) {
        throw;
    } catch (const css::deployment::DeploymentException &) {
        throw;
    } catch (const css::uno::Exception & e) {
        css::uno::Any a(cppu::getCaughtException());
        throw css::deployment::DeploymentException(
            e.Message, Reference< css::uno::XInterface >(), a);
    }
}

FileDoesNotExistFilter::FileDoesNotExistFilter(
    const Reference< css::ucb::XCommandEnvironment >& xCmdEnv):
    m_bExist(true), m_xCommandEnv(xCmdEnv)
{}

    // XCommandEnvironment
Reference<css::task::XInteractionHandler >
    FileDoesNotExistFilter::getInteractionHandler()
{
    return static_cast<css::task::XInteractionHandler*>(this);
}

Reference<css::ucb::XProgressHandler >
    FileDoesNotExistFilter::getProgressHandler()
{
    return m_xCommandEnv.is()
        ? m_xCommandEnv->getProgressHandler()
        : Reference<css::ucb::XProgressHandler>();
}

// XInteractionHandler
//If the interaction was caused by a non-existing file which is specified in the ctor
//of FileDoesNotExistFilter, then we do nothing
void  FileDoesNotExistFilter::handle(
        Reference<css::task::XInteractionRequest > const & xRequest )
{
    css::uno::Any request( xRequest->getRequest() );

    css::ucb::InteractiveIOException ioexc;
    if ((request>>= ioexc)
        && (ioexc.Code == css::ucb::IOErrorCode_NOT_EXISTING
            || ioexc.Code == css::ucb::IOErrorCode_NOT_EXISTING_PATH))
    {
        m_bExist = false;
        return;
    }
    Reference<css::task::XInteractionHandler> xInteraction;
    if (m_xCommandEnv.is()) {
        xInteraction = m_xCommandEnv->getInteractionHandler();
    }
    if (xInteraction.is()) {
        xInteraction->handle(xRequest);
    }
}

}

namespace dp_misc {

DescriptionInfoset getDescriptionInfoset(std::u16string_view sExtensionFolderURL)
{
    Reference< css::xml::dom::XNode > root;
    Reference<css::uno::XComponentContext> context(
        comphelper::getProcessComponentContext());
    try {
        root =
            ExtensionDescription(
                context, sExtensionFolderURL,
                Reference< css::ucb::XCommandEnvironment >()).
            getRootElement();
    } catch (const NoDescriptionException &) {
    } catch (const css::deployment::DeploymentException & e) {
        css::uno::Any anyEx = cppu::getCaughtException();
        throw css::lang::WrappedTargetRuntimeException(
            "com.sun.star.deployment.DeploymentException: " + e.Message,
            nullptr, anyEx );
    }
    return DescriptionInfoset(context, root);
}

DescriptionInfoset::DescriptionInfoset(
    css::uno::Reference< css::uno::XComponentContext > const & context,
    css::uno::Reference< css::xml::dom::XNode > const & element):
    m_context(context),
    m_element(element)
{
    if (m_element.is()) {
        m_xpath = css::xml::xpath::XPathAPI::create(context);
        m_xpath->registerNS("desc", element->getNamespaceURI());
        m_xpath->registerNS("xlink", "http://www.w3.org/1999/xlink");
    }
}

DescriptionInfoset::~DescriptionInfoset() {}

::std::optional< OUString > DescriptionInfoset::getIdentifier() const {
    return getOptionalValue("desc:identifier/@value");
}

OUString DescriptionInfoset::getNodeValueFromExpression(OUString const & expression) const
{
    css::uno::Reference< css::xml::dom::XNode > n;
    if (m_element.is()) {
        try {
            n = m_xpath->selectSingleNode(m_element, expression);
        } catch (const css::xml::xpath::XPathException &) {
            // ignore
        }
    }
    return n.is() ? getNodeValue(n) : OUString();
}

void DescriptionInfoset::checkDenylist() const
{
    if (!m_element.is())
        return;

    std::optional< OUString > id(getIdentifier());
    if (!id)
        return; // nothing to check
    OUString currentversion(getVersion());
    if (currentversion.getLength() == 0)
        return;  // nothing to check

    css::uno::Sequence<css::uno::Any> args(comphelper::InitAnyPropertySequence(
    {
        {"nodepath", css::uno::Any(OUString("/org.openoffice.Office.ExtensionDependencies/Extensions"))}
    }));
    css::uno::Reference< css::container::XNameAccess > denylist(
        (css::configuration::theDefaultProvider::get(m_context)
         ->createInstanceWithArguments(
             "com.sun.star.configuration.ConfigurationAccess", args)),
        css::uno::UNO_QUERY_THROW);

    // check first if a denylist entry is available
    if (!(denylist.is() && denylist->hasByName(*id)))        return;

    css::uno::Reference< css::beans::XPropertySet > extProps(
        denylist->getByName(*id), css::uno::UNO_QUERY_THROW);

    css::uno::Any anyValue = extProps->getPropertyValue("Versions");

    css::uno::Sequence< OUString > blversions;
    anyValue >>= blversions;

    // check if the current version requires further dependency checks from the denylist
    if (!checkDenylistVersion(currentversion, blversions))        return;

    anyValue = extProps->getPropertyValue("Dependencies");
    OUString udeps;
    anyValue >>= udeps;

    if (udeps.getLength() == 0)
        return; // nothing todo

    OString xmlDependencies = OUStringToOString(udeps, RTL_TEXTENCODING_UNICODE);

    css::uno::Reference< css::xml::dom::XDocumentBuilder> docbuilder(
        m_context->getServiceManager()->createInstanceWithContext("com.sun.star.xml.dom.DocumentBuilder", m_context),
        css::uno::UNO_QUERY_THROW);

    css::uno::Sequence< sal_Int8 > byteSeq(reinterpret_cast<const sal_Int8*>(xmlDependencies.getStr()), xmlDependencies.getLength());

    css::uno::Reference< css::io::XInputStream> inputstream( css::io::SequenceInputStream::createStreamFromSequence(m_context, byteSeq),
                                                             css::uno::UNO_QUERY_THROW);

    css::uno::Reference< css::xml::dom::XDocument > xDocument(docbuilder->parse(inputstream));
    css::uno::Reference< css::xml::dom::XElement > xElement(xDocument->getDocumentElement());
    css::uno::Reference< css::xml::dom::XNodeList > xDeps(xElement->getChildNodes());
    sal_Int32 nLen = xDeps->getLength();

    // get the parent xml document  of current description info for the import
    css::uno::Reference< css::xml::dom::XDocument > xCurrentDescInfo(m_element->getOwnerDocument());

    // get dependency node of current description info to merge the new dependencies from the denylist
    css::uno::Reference< css::xml::dom::XNode > xCurrentDeps(
        m_xpath->selectSingleNode(m_element, "desc:dependencies"));

    // if no dependency node exists, create a new one in the current description info
    if (!xCurrentDeps.is()) {
        css::uno::Reference< css::xml::dom::XNode > xNewDepNode(
            xCurrentDescInfo->createElementNS(
                "http://openoffice.org/extensions/description/2006",
                "dependencies"), css::uno::UNO_QUERY_THROW);
        m_element->appendChild(xNewDepNode);
        xCurrentDeps = m_xpath->selectSingleNode(m_element, "desc:dependencies");
    }

    for (sal_Int32 i=0; i<nLen; i++) {
        css::uno::Reference< css::xml::dom::XNode > xNode(xDeps->item(i));
        css::uno::Reference< css::xml::dom::XElement > xDep(xNode, css::uno::UNO_QUERY);
        if (xDep.is()) {
            // found valid denylist dependency, import the node first and append it to the existing dependency node
            css::uno::Reference< css::xml::dom::XNode > importedNode = xCurrentDescInfo->importNode(xNode, true);
            xCurrentDeps->appendChild(importedNode);
        }
    }
}

bool DescriptionInfoset::checkDenylistVersion(
    std::u16string_view currentversion,
    css::uno::Sequence< OUString > const & versions)
{
    sal_Int32 nLen = versions.getLength();
    for (sal_Int32 i=0; i<nLen; i++) {
        if (currentversion == versions[i])
            return true;
    }

    return false;
}

OUString DescriptionInfoset::getVersion() const
{
    return getNodeValueFromExpression( "desc:version/@value" );
}

css::uno::Sequence< OUString > DescriptionInfoset::getSupportedPlatforms() const
{
    //When there is no description.xml then we assume that we support all platforms
    if (! m_element.is())
    {
        return { OUString("all") };
    }

    //Check if the <platform> element was provided. If not the default is "all" platforms
    css::uno::Reference< css::xml::dom::XNode > nodePlatform(
        m_xpath->selectSingleNode(m_element, "desc:platform"));
    if (!nodePlatform.is())
    {
        return { OUString("all") };
    }

    //There is a platform element.
    const OUString value = getNodeValueFromExpression("desc:platform/@value");
    //parse the string, it can contained multiple strings separated by commas
    std::vector< OUString> vec;
    sal_Int32 nIndex = 0;
    do
    {
        const OUString aToken( o3tl::trim(o3tl::getToken(value, 0, ',', nIndex )) );
        if (!aToken.isEmpty())
            vec.push_back(aToken);

    }
    while (nIndex >= 0);

    return comphelper::containerToSequence(vec);
}

css::uno::Reference< css::xml::dom::XNodeList >
DescriptionInfoset::getDependencies() const {
    if (m_element.is()) {
        try {
            // check the extension denylist first and expand the dependencies if applicable
            checkDenylist();

            return m_xpath->selectNodeList(m_element, "desc:dependencies/*");
        } catch (const css::xml::xpath::XPathException &) {
            // ignore
        }
    }
    return new EmptyNodeList;
}

css::uno::Sequence< OUString >
DescriptionInfoset::getUpdateInformationUrls() const {
    return getUrls("desc:update-information/desc:src/@xlink:href");
}

css::uno::Sequence< OUString >
DescriptionInfoset::getUpdateDownloadUrls() const
{
    return getUrls("desc:update-download/desc:src/@xlink:href");
}

OUString DescriptionInfoset::getIconURL( bool bHighContrast ) const
{
    css::uno::Sequence< OUString > aStrList = getUrls( "desc:icon/desc:default/@xlink:href" );
    css::uno::Sequence< OUString > aStrListHC = getUrls( "desc:icon/desc:high-contrast/@xlink:href" );

    if ( bHighContrast && aStrListHC.hasElements() && !aStrListHC[0].isEmpty() )
        return aStrListHC[0];

    if ( aStrList.hasElements() && !aStrList[0].isEmpty() )
        return aStrList[0];

    return OUString();
}

::std::optional< OUString > DescriptionInfoset::getLocalizedUpdateWebsiteURL()
    const
{
    bool bParentExists = false;
    const OUString sURL (getLocalizedHREFAttrFromChild("/desc:description/desc:update-website", &bParentExists ));

    if (!sURL.isEmpty())
        return ::std::optional< OUString >(sURL);
    else
        return bParentExists ? ::std::optional< OUString >(OUString()) :
            ::std::optional< OUString >();
}

::std::optional< OUString > DescriptionInfoset::getOptionalValue(
    OUString const & expression) const
{
    css::uno::Reference< css::xml::dom::XNode > n;
    if (m_element.is()) {
        try {
            n = m_xpath->selectSingleNode(m_element, expression);
        } catch (const css::xml::xpath::XPathException &) {
            // ignore
        }
    }
    return n.is()
        ? ::std::optional< OUString >(getNodeValue(n))
        : ::std::optional< OUString >();
}

css::uno::Sequence< OUString > DescriptionInfoset::getUrls(
    OUString const & expression) const
{
    css::uno::Reference< css::xml::dom::XNodeList > ns;
    if (m_element.is()) {
        try {
            ns = m_xpath->selectNodeList(m_element, expression);
        } catch (const css::xml::xpath::XPathException &) {
            // ignore
        }
    }
    css::uno::Sequence< OUString > urls(ns.is() ? ns->getLength() : 0);
    auto urlsRange = asNonConstRange(urls);
    for (::sal_Int32 i = 0; i < urls.getLength(); ++i) {
        urlsRange[i] = getNodeValue(ns->item(i));
    }
    return urls;
}

std::pair< OUString, OUString > DescriptionInfoset::getLocalizedPublisherNameAndURL() const
{
    css::uno::Reference< css::xml::dom::XNode > node =
        getLocalizedChild("desc:publisher");

    OUString sPublisherName;
    OUString sURL;
    if (node.is())
    {
        css::uno::Reference< css::xml::dom::XNode > xPathName;
        try {
            xPathName = m_xpath->selectSingleNode(node, "text()");
        } catch (const css::xml::xpath::XPathException &) {
            // ignore
        }
        OSL_ASSERT(xPathName.is());
        if (xPathName.is())
            sPublisherName = xPathName->getNodeValue();

        css::uno::Reference< css::xml::dom::XNode > xURL;
        try {
            xURL = m_xpath->selectSingleNode(node, "@xlink:href");
        } catch (const css::xml::xpath::XPathException &) {
            // ignore
        }
        OSL_ASSERT(xURL.is());
        if (xURL.is())
           sURL = xURL->getNodeValue();
    }
    return std::make_pair(sPublisherName, sURL);
}

OUString DescriptionInfoset::getLocalizedReleaseNotesURL() const
{
    return getLocalizedHREFAttrFromChild("/desc:description/desc:release-notes", nullptr);
}

OUString DescriptionInfoset::getLocalizedDisplayName() const
{
    css::uno::Reference< css::xml::dom::XNode > node =
        getLocalizedChild("desc:display-name");
    if (node.is())
    {
        css::uno::Reference< css::xml::dom::XNode > xtext;
        try {
            xtext = m_xpath->selectSingleNode(node, "text()");
        } catch (const css::xml::xpath::XPathException &) {
            // ignore
        }
        if (xtext.is())
            return xtext->getNodeValue();
    }
    return OUString();
}

OUString DescriptionInfoset::getLocalizedLicenseURL() const
{
    return getLocalizedHREFAttrFromChild("/desc:description/desc:registration/desc:simple-license", nullptr);

}

::std::optional<SimpleLicenseAttributes>
DescriptionInfoset::getSimpleLicenseAttributes() const
{
    //Check if the node exist
    css::uno::Reference< css::xml::dom::XNode > n;
    if (m_element.is()) {
        try {
            n = m_xpath->selectSingleNode(m_element, "/desc:description/desc:registration/desc:simple-license/@accept-by");
        } catch (const css::xml::xpath::XPathException &) {
            // ignore
        }
        if (n.is())
        {
            SimpleLicenseAttributes attributes;
            attributes.acceptBy =
                getNodeValueFromExpression("/desc:description/desc:registration/desc:simple-license/@accept-by");

            ::std::optional< OUString > suppressOnUpdate = getOptionalValue("/desc:description/desc:registration/desc:simple-license/@suppress-on-update");
            if (suppressOnUpdate)
                attributes.suppressOnUpdate = o3tl::equalsIgnoreAsciiCase(o3tl::trim(*suppressOnUpdate), u"true");
            else
                attributes.suppressOnUpdate = false;

            ::std::optional< OUString > suppressIfRequired = getOptionalValue("/desc:description/desc:registration/desc:simple-license/@suppress-if-required");
            if (suppressIfRequired)
                attributes.suppressIfRequired = o3tl::equalsIgnoreAsciiCase(o3tl::trim(*suppressIfRequired), u"true");
            else
                attributes.suppressIfRequired = false;

            return ::std::optional<SimpleLicenseAttributes>(attributes);
        }
    }
    return ::std::optional<SimpleLicenseAttributes>();
}

OUString DescriptionInfoset::getLocalizedDescriptionURL() const
{
    return getLocalizedHREFAttrFromChild("/desc:description/desc:extension-description", nullptr);
}

css::uno::Reference< css::xml::dom::XNode >
DescriptionInfoset::getLocalizedChild( const OUString & sParent) const
{
    if ( ! m_element.is() || sParent.isEmpty())
        return css::uno::Reference< css::xml::dom::XNode > ();

    css::uno::Reference< css::xml::dom::XNode > xParent;
    try {
        xParent = m_xpath->selectSingleNode(m_element, sParent);
    } catch (const css::xml::xpath::XPathException &) {
        // ignore
    }
    css::uno::Reference<css::xml::dom::XNode> nodeMatch;
    if (xParent.is())
    {
        nodeMatch = matchLanguageTag(xParent, getOfficeLanguageTag().getBcp47());

        //office: en-DE, en, en-DE-altmark
        if (! nodeMatch.is())
        {
            // Already tried full tag, continue with first fallback.
            const std::vector< OUString > aFallbacks( getOfficeLanguageTag().getFallbackStrings( false));
            for (auto const& fallback : aFallbacks)
            {
                nodeMatch = matchLanguageTag(xParent, fallback);
                if (nodeMatch.is())
                    break;
            }
            if (! nodeMatch.is())
                nodeMatch = getChildWithDefaultLocale(xParent);
        }
    }

    return nodeMatch;
}

css::uno::Reference<css::xml::dom::XNode>
DescriptionInfoset::matchLanguageTag(
    css::uno::Reference< css::xml::dom::XNode > const & xParent, std::u16string_view rTag) const
{
    OSL_ASSERT(xParent.is());
    css::uno::Reference<css::xml::dom::XNode> nodeMatch;

    //first try exact match for lang
    const OUString exp1(OUString::Concat("*[@lang=\"") + rTag + "\"]");
    try {
        nodeMatch = m_xpath->selectSingleNode(xParent, exp1);
    } catch (const css::xml::xpath::XPathException &) {
        // ignore
    }

    //try to match in strings that also have a country and/or variant, for
    //example en  matches in en-US-montana, en-US, en-montana
    if (!nodeMatch.is())
    {
        const OUString exp2(
            OUString::Concat("*[starts-with(@lang,\"") + rTag + "-\")]");
        try {
            nodeMatch = m_xpath->selectSingleNode(xParent, exp2);
        } catch (const css::xml::xpath::XPathException &) {
            // ignore
        }
    }
    return nodeMatch;
}

css::uno::Reference<css::xml::dom::XNode>
DescriptionInfoset::getChildWithDefaultLocale(css::uno::Reference< css::xml::dom::XNode >
                                    const & xParent) const
{
    OSL_ASSERT(xParent.is());
    if ( xParent->getNodeName() == "simple-license" )
    {
        css::uno::Reference<css::xml::dom::XNode> nodeDefault;
        try {
            nodeDefault = m_xpath->selectSingleNode(xParent, "@default-license-id");
        } catch (const css::xml::xpath::XPathException &) {
            // ignore
        }
        if (nodeDefault.is())
        {
            //The old way
            const OUString exp1("desc:license-text[@license-id = \""
                + nodeDefault->getNodeValue()
                + "\"]");
            try {
                return m_xpath->selectSingleNode(xParent, exp1);
            } catch (const css::xml::xpath::XPathException &) {
                // ignore
            }
        }
    }

    try {
        return m_xpath->selectSingleNode(xParent, "*[1]");
    } catch (const css::xml::xpath::XPathException &) {
        // ignore
        return nullptr;
    }
}

OUString DescriptionInfoset::getLocalizedHREFAttrFromChild(
    OUString const & sXPathParent, bool * out_bParentExists)
    const
{
    css::uno::Reference< css::xml::dom::XNode > node =
        getLocalizedChild(sXPathParent);

    OUString sURL;
    if (node.is())
    {
        if (out_bParentExists)
            *out_bParentExists = true;
        css::uno::Reference< css::xml::dom::XNode > xURL;
        try {
            xURL = m_xpath->selectSingleNode(node, "@xlink:href");
        } catch (const css::xml::xpath::XPathException &) {
            // ignore
        }
        OSL_ASSERT(xURL.is());
        if (xURL.is())
            sURL = xURL->getNodeValue();
    }
    else
    {
        if (out_bParentExists)
            *out_bParentExists = false;
    }
    return sURL;
}

}

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