xmlDocPtr XSLStyleSheet::locateStylesheetSubResource(xmlDocPtr parentDoc, const xmlChar* uri)
{
    bool matchedParent = (parentDoc == document());
    for (unsigned i = 0; i < m_children.size(); ++i) {
        XSLImportRule* import = m_children.at(i).get();
        XSLStyleSheet* child = import->styleSheet();
        if (!child)
            continue;
        if (matchedParent) {
            if (child->processed())
                continue; // libxslt has been given this sheet already.

            // Check the URI of the child stylesheet against the doc URI.
            // In order to ensure that libxml canonicalized both URLs, we get the original href
            // string from the import rule and canonicalize it using libxml before comparing it
            // with the URI argument.
            CString importHref = import->href().utf8();
            xmlChar* base = xmlNodeGetBase(parentDoc, (xmlNodePtr)parentDoc);
            xmlChar* childURI = xmlBuildURI((const xmlChar*)importHref.data(), base);
            bool equalURIs = xmlStrEqual(uri, childURI);
            xmlFree(base);
            xmlFree(childURI);
            if (equalURIs) {
                child->markAsProcessed();
                return child->document();
            }
            continue;
        }
        xmlDocPtr result = import->styleSheet()->locateStylesheetSubResource(parentDoc, uri);
        if (result)
            return result;
    }

    return 0;
}

Document* XSLStyleSheet::ownerDocument()
{
    for (XSLStyleSheet* styleSheet = this; styleSheet; styleSheet = styleSheet->parentStyleSheet()) {
        Node* node = styleSheet->ownerNode();
        if (node)
            return &node->document();
    }
    return 0;
}

Document* XSLStyleSheet::ownerDocument()
{
    for (XSLStyleSheet* styleSheet = this; styleSheet; styleSheet = styleSheet->parentStyleSheet()) {
        if (styleSheet->m_ownerDocument)
            return styleSheet->m_ownerDocument.get();
        Node* node = styleSheet->ownerNode();
        if (node)
            return &node->document();
    }
    return nullptr;
}

void XSLImportRule::setXSLStyleSheet(const String& href, const KURL& baseURL, const String& sheet)
{
    if (m_styleSheet)
        m_styleSheet->setParentStyleSheet(0);

    m_styleSheet = XSLStyleSheet::create(this, href, baseURL);

    XSLStyleSheet* parent = parentStyleSheet();
    if (parent)
        m_styleSheet->setParentStyleSheet(parent);

    m_styleSheet->parseString(sheet);
    m_loading = false;

    if (parent)
        parent->checkLoaded();
}

void XSLImportRule::loadSheet()
{
    CachedResourceLoader* cachedResourceLoader = 0;

    XSLStyleSheet* rootSheet = parentStyleSheet();

    if (rootSheet) {
        while (XSLStyleSheet* parentSheet = rootSheet->parentStyleSheet())
            rootSheet = parentSheet;
    }

    if (rootSheet)
        cachedResourceLoader = rootSheet->cachedResourceLoader();
    
    String absHref = m_strHref;
    XSLStyleSheet* parentSheet = parentStyleSheet();
    if (!parentSheet->baseURL().isNull())
        // use parent styleheet's URL as the base URL
        absHref = KURL(parentSheet->baseURL(), m_strHref).string();
    
    // Check for a cycle in our import chain.  If we encounter a stylesheet
    // in our parent chain with the same URL, then just bail.
    for (XSLStyleSheet* parentSheet = parentStyleSheet(); parentSheet; parentSheet = parentSheet->parentStyleSheet()) {
        if (absHref == parentSheet->baseURL().string())
            return;
    }
    
    CachedResourceRequest request(ResourceRequest(cachedResourceLoader->document()->completeURL(absHref)));
    if (m_cachedSheet)
        m_cachedSheet->removeClient(this);
    m_cachedSheet = cachedResourceLoader->requestXSLStyleSheet(request);
    
    if (m_cachedSheet) {
        m_cachedSheet->addClient(this);
        
        // If the imported sheet is in the cache, then setXSLStyleSheet gets called,
        // and the sheet even gets parsed (via parseString).  In this case we have
        // loaded (even if our subresources haven't), so if we have a stylesheet after
        // checking the cache, then we've clearly loaded.
        if (!m_styleSheet)
            m_loading = true;
    }
}