frameloader.cpp

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    if (m_encodingWasChosenByUser && !m_encoding.isEmpty())
        return m_encoding;
    if (m_decoder && m_decoder->encoding().isValid())
        return m_decoder->encoding().name();
    Settings* settings = m_frame->settings();
    return settings ? settings->defaultTextEncodingName() : String();
}

bool FrameLoader::gotoAnchor(const String& name)
{
    ASSERT(m_frame->document());

    if (!m_frame->document()->haveStylesheetsLoaded()) {
        m_frame->document()->setGotoAnchorNeededAfterStylesheetsLoad(true);
        return false;
    }

    m_frame->document()->setGotoAnchorNeededAfterStylesheetsLoad(false);

    Element* anchorNode = m_frame->document()->findAnchor(name);

#if ENABLE(SVG)
    if (m_frame->document()->isSVGDocument()) {
        if (name.startsWith("xpointer(")) {
            // We need to parse the xpointer reference here
        } else if (name.startsWith("svgView(")) {
            RefPtr<SVGSVGElement> svg = static_cast<SVGDocument*>(m_frame->document())->rootElement();
            if (!svg->currentView()->parseViewSpec(name))
                return false;
            svg->setUseCurrentView(true);
        } else {
            if (anchorNode && anchorNode->hasTagName(SVGNames::viewTag)) {
                RefPtr<SVGViewElement> viewElement = anchorNode->hasTagName(SVGNames::viewTag) ? static_cast<SVGViewElement*>(anchorNode) : 0;
                if (viewElement.get()) {
                    RefPtr<SVGSVGElement> svg = static_cast<SVGSVGElement*>(SVGLocatable::nearestViewportElement(viewElement.get()));
                    svg->inheritViewAttributes(viewElement.get());
                }
            }
        }
        // FIXME: need to decide which <svg> to focus on, and zoom to that one
        // FIXME: need to actually "highlight" the viewTarget(s)
    }
#endif

    m_frame->document()->setCSSTarget(anchorNode); // Setting to null will clear the current target.
  
    // Implement the rule that "" and "top" both mean top of page as in other browsers.
    if (!anchorNode && !(name.isEmpty() || equalIgnoringCase(name, "top")))
        return false;

    // We need to update the layout before scrolling, otherwise we could
    // really mess things up if an anchor scroll comes at a bad moment.
    m_frame->document()->updateRendering();
    // Only do a layout if changes have occurred that make it necessary.
    if (m_frame->view() && m_frame->contentRenderer() && m_frame->contentRenderer()->needsLayout())
        m_frame->view()->layout();
  
    // Scroll nested layers and frames to reveal the anchor.
    // Align to the top and to the closest side (this matches other browsers).
    RenderObject* renderer;
    IntRect rect;
    if (!anchorNode)
        renderer = m_frame->document()->renderer(); // top of document
    else {
        renderer = anchorNode->renderer();
        rect = anchorNode->getRect();
    }
    if (renderer)
        renderer->enclosingLayer()->scrollRectToVisible(rect, true, ScrollAlignment::alignToEdgeIfNeeded, ScrollAlignment::alignTopAlways);

    return true;
}

bool FrameLoader::requestObject(RenderPart* renderer, const String& url, const AtomicString& frameName,
    const String& mimeType, const Vector<String>& paramNames, const Vector<String>& paramValues)
{
    if (url.isEmpty() && mimeType.isEmpty())
        return false;

    KURL completedURL;
    if (!url.isEmpty())
        completedURL = completeURL(url);

    bool useFallback;
    if (shouldUsePlugin(completedURL, mimeType, renderer->hasFallbackContent(), useFallback)) {
        Settings* settings = m_frame->settings();
        if (!settings || !settings->arePluginsEnabled() || 
            (!settings->isJavaEnabled() && MIMETypeRegistry::isJavaAppletMIMEType(mimeType)))
            return false;
        return loadPlugin(renderer, completedURL, mimeType, paramNames, paramValues, useFallback);
    }

    ASSERT(renderer->node()->hasTagName(objectTag) || renderer->node()->hasTagName(embedTag));
    HTMLPlugInElement* element = static_cast<HTMLPlugInElement*>(renderer->node());
    
    // FIXME: OK to always make a new frame? When does the old frame get removed?
    return loadSubframe(element, completedURL, frameName, m_outgoingReferrer);
}

bool FrameLoader::shouldUsePlugin(const KURL& url, const String& mimeType, bool hasFallback, bool& useFallback)
{
    if (m_client->shouldUsePluginDocument(mimeType)) {
        useFallback = false;
        return true;
    }

    // Allow other plug-ins to win over QuickTime because if the user has installed a plug-in that
    // can handle TIFF (which QuickTime can also handle) they probably intended to override QT.
    if (m_frame->page() && (mimeType == "image/tiff" || mimeType == "image/tif" || mimeType == "image/x-tiff")) {
        const PluginData* pluginData = m_frame->page()->pluginData();
        String pluginName = pluginData ? pluginData->pluginNameForMimeType(mimeType) : String();
        if (!pluginName.isEmpty() && !pluginName.contains("QuickTime", false)) 
            return true;
    }
        
    ObjectContentType objectType = m_client->objectContentType(url, mimeType);
    // If an object's content can't be handled and it has no fallback, let
    // it be handled as a plugin to show the broken plugin icon.
    useFallback = objectType == ObjectContentNone && hasFallback;
    return objectType == ObjectContentNone || objectType == ObjectContentNetscapePlugin || objectType == ObjectContentOtherPlugin;
}

static HTMLPlugInElement* toPlugInElement(Node* node)
{
    if (!node)
        return 0;

#if ENABLE(PLUGIN_PROXY_FOR_VIDEO)
    ASSERT(node->hasTagName(objectTag) || node->hasTagName(embedTag) 
        || node->hasTagName(videoTag) || node->hasTagName(audioTag)
        || node->hasTagName(appletTag));
#else
    ASSERT(node->hasTagName(objectTag) || node->hasTagName(embedTag) 
        || node->hasTagName(appletTag));
#endif

    return static_cast<HTMLPlugInElement*>(node);
}
    
bool FrameLoader::loadPlugin(RenderPart* renderer, const KURL& url, const String& mimeType, 
    const Vector<String>& paramNames, const Vector<String>& paramValues, bool useFallback)
{
    Widget* widget = 0;

    if (renderer && !useFallback) {
        HTMLPlugInElement* element = toPlugInElement(renderer->node());

        if (!canLoad(url, String(), frame()->document())) {
            FrameLoader::reportLocalLoadFailed(m_frame, url.string());
            return false;
        }

        widget = m_client->createPlugin(IntSize(renderer->contentWidth(), renderer->contentHeight()), 
                                        element, url, paramNames, paramValues, mimeType,
                                        m_frame->document()->isPluginDocument());
        if (widget) {
            renderer->setWidget(widget);
            m_containsPlugIns = true;
        }
    }

    return widget != 0;
}

void FrameLoader::clearRecordedFormValues()
{
    m_formAboutToBeSubmitted = 0;
    m_formValuesAboutToBeSubmitted.clear();
}

void FrameLoader::setFormAboutToBeSubmitted(PassRefPtr<HTMLFormElement> element)
{
    m_formAboutToBeSubmitted = element;
}

void FrameLoader::recordFormValue(const String& name, const String& value)
{
    m_formValuesAboutToBeSubmitted.set(name, value);
}

void FrameLoader::parentCompleted()
{
    if (m_scheduledRedirection && !m_redirectionTimer.isActive())
        startRedirectionTimer();
}

String FrameLoader::outgoingReferrer() const
{
    return m_outgoingReferrer;
}

String FrameLoader::outgoingOrigin() const
{
    return m_frame->document()->securityOrigin()->toString();
}

Frame* FrameLoader::opener()
{
    return m_opener;
}

void FrameLoader::setOpener(Frame* opener)
{
    if (m_opener)
        m_opener->loader()->m_openedFrames.remove(m_frame);
    if (opener)
        opener->loader()->m_openedFrames.add(m_frame);
    m_opener = opener;

    if (m_frame->document()) {
        m_frame->document()->initSecurityContext();
        m_frame->domWindow()->setSecurityOrigin(m_frame->document()->securityOrigin());
    }
}

bool FrameLoader::openedByDOM() const
{
    return m_openedByDOM;
}

void FrameLoader::setOpenedByDOM()
{
    m_openedByDOM = true;
}

void FrameLoader::handleFallbackContent()
{
    HTMLFrameOwnerElement* owner = m_frame->ownerElement();
    if (!owner || !owner->hasTagName(objectTag))
        return;
    static_cast<HTMLObjectElement*>(owner)->renderFallbackContent();
}

void FrameLoader::provisionalLoadStarted()
{
    Page* page = m_frame->page();
    
    // this is used to update the current history item
    // in the event of a navigation aytime during loading
    m_navigationDuringLoad = false;
    if (page) {
        Document *document = page->mainFrame()->document();
        m_navigationDuringLoad = !page->mainFrame()->loader()->isComplete() || (document && document->processingLoadEvent());
    }
    
    m_firstLayoutDone = false;
    cancelRedirection(true);
    m_client->provisionalLoadStarted();
}

bool FrameLoader::userGestureHint()
{
    Frame* frame = m_frame->tree()->top();
    if (!frame->script()->isEnabled())
        return true; // If JavaScript is disabled, a user gesture must have initiated the navigation.
    return frame->script()->processingUserGesture(); // FIXME: Use pageIsProcessingUserGesture.
}

void FrameLoader::didNotOpenURL(const KURL& url)
{
    if (m_submittedFormURL == url)
        m_submittedFormURL = KURL();
}

void FrameLoader::resetMultipleFormSubmissionProtection()
{
    m_submittedFormURL = KURL();
}

void FrameLoader::setEncoding(const String& name, bool userChosen)
{
    if (!m_workingURL.isEmpty())
        receivedFirstData();
    m_encoding = name;
    m_encodingWasChosenByUser = userChosen;
}

void FrameLoader::addData(const char* bytes, int length)
{
    ASSERT(m_workingURL.isEmpty());
    ASSERT(m_frame->document());
    ASSERT(m_frame->document()->parsing());
    write(bytes, length);
}

bool FrameLoader::canCachePageContainingThisFrame()
{
    return m_documentLoader
        && m_documentLoader->mainDocumentError().isNull()
        && !m_frame->tree()->childCount()
        // FIXME: If we ever change this so that frames with plug-ins will be cached,
        // we need to make sure that we don't cache frames that have outstanding NPObjects
        // (objects created by the plug-in). Since there is no way to pause/resume a Netscape plug-in,
        // they would need to be destroyed and then recreated, and there is no way that we can recreate
        // the right NPObjects. See <rdar://problem/5197041> for more information.
        && !m_containsPlugIns
        && !m_URL.protocolIs("https")
        && !m_frame->document()->hasWindowEventListener(eventNames().unloadEvent)
#if ENABLE(DATABASE)
        && !m_frame->document()->hasOpenDatabases()
#endif
        && !m_frame->document()->usingGeolocation()
        && m_currentHistoryItem
        && !isQuickRedirectComing()
        && !m_documentLoader->isLoadingInAPISense()
        && !m_documentLoader->isStopping()
        && m_frame->document()->canSuspendActiveDOMObjects()
#if ENABLE(OFFLINE_WEB_APPLICATIONS)
        // FIXME: We should investigating caching frames that have an associated
        // application cache. <rdar://problem/5917899> tracks that work.
        && !m_documentLoader->applicationCache()
        && !m_documentLoader->candidateApplicationCacheGroup()
#endif
        && m_client->canCachePage()
        ;
}

bool FrameLoader::canCachePage()
{
#ifndef NDEBUG
    logCanCachePageDecision();
#endif
    
    // Cache the page, if possible.
    // Don't write to the cache if in the middle of a redirect, since we will want to
    // store the final page we end up on.
    // No point writing to the cache on a reload or loadSame, since we will just write
    // over it again when we leave that page.
    // FIXME: <rdar://problem/4886592> - We should work out the complexities of caching pages with frames as they
    // are the most interesting pages on the web, and often those that would benefit the most from caching!
    FrameLoadType loadType = this->loadType();
    
    return !m_frame->tree()->parent()
        && canCachePageContainingThisFrame()
        && m_frame->page()
        && m_frame->page()->backForwardList()->enabled()
        && m_frame->page()->backForwardList()->capacity() > 0
        && m_frame->page()->settings()->usesPageCache()
        && loadType != FrameLoadTypeReload 
        && loadType != FrameLoadTypeReloadFromOrigin
        && loadType != FrameLoadTypeSame
        ;
}

#ifndef NDEBUG
static String& pageCacheLogPrefix(int indentLevel)
{
    static int previousIndent = -1;
    DEFINE_STATIC_LOCAL(String, prefix, ());
    
    if (indentLevel != previousIndent) {    
        previousIndent = indentLevel;
        prefix.truncate(0);
        for (int i = 0; i < previousIndent; ++i)
            prefix += "    ";
    }
    
    return prefix;
}

static void pageCacheLog(const String& prefix, const String& message)
{
    LOG(PageCache, "%s%s", prefix.utf8().data(), message.utf8().data());
}

#define PCLOG(...) pageCacheLog(pageCacheLogPrefix(indentLevel), String::format(__VA_ARGS__))

void FrameLoader::logCanCachePageDecision()
{
    // Only bother logging for main frames that have actually loaded and have content.
    if (m_creatingInitialEmptyDocument)
        return;
    KURL currentURL = m_documentLoader ? m_documentLoader->url() : KURL();
    if (currentURL.isEmpty())
        return;

    int indentLevel = 0;
    PCLOG("--------\n Determining if page can be cached:");

    bool cannotCache = !logCanCacheFrame