root/Source/core/html/HTMLLinkElement.cpp

DEFINITIONS

1. parseSizes
2. linkLoadEventSender
3. parseSizesAttribute
4. m_isInShadowTree
5. create
6. parseAttribute
7. shouldLoadLink
8. loadLink
9. linkResourceToProcess
10. linkStyle
11. linkImport
12. importOwnsLoader
13. import
14. process
15. insertedInto
16. removedFrom
17. finishParsingChildren
18. styleSheetIsLoading
19. linkLoaded
20. linkLoadingErrored
21. didStartLinkPrerender
22. didStopLinkPrerender
23. didSendLoadForLinkPrerender
24. didSendDOMContentLoadedForLinkPrerender
25. sheetLoaded
26. notifyLoadedSheetAndAllCriticalSubresources
27. dispatchPendingLoadEvents
28. dispatchPendingEvent
29. scheduleEvent
30. startLoadingDynamicSheet
31. isURLAttribute
32. hasLegalLinkAttribute
33. subResourceAttributeName
34. href
35. rel
36. type
37. async
38. iconType
39. iconSizes
40. sizes
41. create
42. m_loadedSheet
43. document
44. setCSSStyleSheet
45. sheetLoaded
46. notifyLoadedSheetAndAllCriticalSubresources
47. startLoadingDynamicSheet
48. clearSheet
49. styleSheetIsLoading
50. addPendingSheet
51. removePendingSheet
52. setDisabledState
53. process
54. setSheetTitle
55. ownerRemoved

/*
 * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
 *           (C) 1999 Antti Koivisto (koivisto@kde.org)
 *           (C) 2001 Dirk Mueller (mueller@kde.org)
 * Copyright (C) 2003, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
 * Copyright (C) 2009 Rob Buis (rwlbuis@gmail.com)
 * Copyright (C) 2011 Google Inc. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

#include "config.h"
#include "core/html/HTMLLinkElement.h"

#include "HTMLNames.h"
#include "RuntimeEnabledFeatures.h"
#include "bindings/v8/ScriptEventListener.h"
#include "core/css/MediaList.h"
#include "core/css/MediaQueryEvaluator.h"
#include "core/css/StyleSheetContents.h"
#include "core/css/resolver/StyleResolver.h"
#include "core/dom/Attribute.h"
#include "core/dom/Document.h"
#include "core/events/Event.h"
#include "core/events/EventSender.h"
#include "core/dom/StyleEngine.h"
#include "core/fetch/CSSStyleSheetResource.h"
#include "core/fetch/FetchRequest.h"
#include "core/fetch/ResourceFetcher.h"
#include "core/frame/FrameView.h"
#include "core/frame/LocalFrame.h"
#include "core/frame/csp/ContentSecurityPolicy.h"
#include "core/html/imports/LinkImport.h"
#include "core/loader/FrameLoader.h"
#include "core/loader/FrameLoaderClient.h"
#include "wtf/StdLibExtras.h"

namespace WebCore {

using namespace HTMLNames;

template <typename CharacterType>
static void parseSizes(const CharacterType* value, unsigned length, Vector<IntSize>& iconSizes)
{
    enum State {
        ParseStart,
        ParseWidth,
        ParseHeight
    };
    int width = 0;
    unsigned start = 0;
    unsigned i = 0;
    State state = ParseStart;
    bool invalid = false;
    for (; i < length; ++i) {
        if (state == ParseWidth) {
            if (value[i] == 'x' || value[i] == 'X') {
                if (i == start) {
                    invalid = true;
                    break;
                }
                width = charactersToInt(value + start, i - start);
                start = i + 1;
                state = ParseHeight;
            } else if (value[i] < '0' || value[i] > '9') {
                invalid = true;
                break;
            }
        } else if (state == ParseHeight) {
            if (value[i] == ' ') {
                if (i == start) {
                    invalid = true;
                    break;
                }
                int height = charactersToInt(value + start, i - start);
                iconSizes.append(IntSize(width, height));
                start = i + 1;
                state = ParseStart;
            } else if (value[i] < '0' || value[i] > '9') {
                invalid = true;
                break;
            }
        } else if (state == ParseStart) {
            if (value[i] >= '0' && value[i] <= '9') {
                start = i;
                state = ParseWidth;
            } else if (value[i] != ' ') {
                invalid = true;
                break;
            }
        }
    }
    if (invalid || state == ParseWidth || (state == ParseHeight && start == i)) {
        iconSizes.clear();
        return;
    }
    if (state == ParseHeight && i > start) {
        int height = charactersToInt(value + start, i - start);
        iconSizes.append(IntSize(width, height));
    }
}

static LinkEventSender& linkLoadEventSender()
{
    DEFINE_STATIC_LOCAL(LinkEventSender, sharedLoadEventSender, (EventTypeNames::load));
    return sharedLoadEventSender;
}

void HTMLLinkElement::parseSizesAttribute(const AtomicString& value, Vector<IntSize>& iconSizes)
{
    ASSERT(iconSizes.isEmpty());
    if (value.isEmpty())
        return;
    if (value.is8Bit())
        parseSizes(value.characters8(), value.length(), iconSizes);
    else
        parseSizes(value.characters16(), value.length(), iconSizes);
}

inline HTMLLinkElement::HTMLLinkElement(Document& document, bool createdByParser)
    : HTMLElement(linkTag, document)
    , m_linkLoader(this)
    , m_sizes(DOMSettableTokenList::create())
    , m_createdByParser(createdByParser)
    , m_isInShadowTree(false)
{
    ScriptWrappable::init(this);
}

PassRefPtr<HTMLLinkElement> HTMLLinkElement::create(Document& document, bool createdByParser)
{
    return adoptRef(new HTMLLinkElement(document, createdByParser));
}

HTMLLinkElement::~HTMLLinkElement()
{
    m_link.clear();

    if (inDocument())
        document().styleEngine()->removeStyleSheetCandidateNode(this);

    linkLoadEventSender().cancelEvent(this);
}

void HTMLLinkElement::parseAttribute(const QualifiedName& name, const AtomicString& value)
{
    if (name == relAttr) {
        m_relAttribute = LinkRelAttribute(value);
        process();
    } else if (name == hrefAttr) {
        process();
    } else if (name == typeAttr) {
        m_type = value;
        process();
    } else if (name == sizesAttr) {
        m_sizes->setValue(value);
        parseSizesAttribute(value, m_iconSizes);
        process();
    } else if (name == mediaAttr) {
        m_media = value.string().lower();
        process();
    } else if (name == disabledAttr) {
        if (LinkStyle* link = linkStyle())
            link->setDisabledState(!value.isNull());
    } else {
        if (name == titleAttr) {
            if (LinkStyle* link = linkStyle())
                link->setSheetTitle(value);
        }

        HTMLElement::parseAttribute(name, value);
    }
}

bool HTMLLinkElement::shouldLoadLink()
{
    return inDocument();
}

bool HTMLLinkElement::loadLink(const String& type, const KURL& url)
{
    return m_linkLoader.loadLink(m_relAttribute, fastGetAttribute(HTMLNames::crossoriginAttr), type, url, document());
}

LinkResource* HTMLLinkElement::linkResourceToProcess()
{
    bool visible = inDocument() && !m_isInShadowTree;
    if (!visible) {
        ASSERT(!linkStyle() || !linkStyle()->hasSheet());
        return 0;
    }

    if (!m_link) {
        if (m_relAttribute.isImport() && RuntimeEnabledFeatures::htmlImportsEnabled())
            m_link = LinkImport::create(this);
        else {
            OwnPtr<LinkStyle> link = LinkStyle::create(this);
            if (fastHasAttribute(disabledAttr))
                link->setDisabledState(true);
            m_link = link.release();
        }
    }

    return m_link.get();
}

LinkStyle* HTMLLinkElement::linkStyle() const
{
    if (!m_link || m_link->type() != LinkResource::Style)
        return 0;
    return static_cast<LinkStyle*>(m_link.get());
}

LinkImport* HTMLLinkElement::linkImport() const
{
    if (!m_link || m_link->type() != LinkResource::Import)
        return 0;
    return static_cast<LinkImport*>(m_link.get());
}

bool HTMLLinkElement::importOwnsLoader() const
{
    LinkImport* import = linkImport();
    if (!import)
        return false;
    return import->ownsLoader();
}

Document* HTMLLinkElement::import() const
{
    if (LinkImport* link = linkImport())
        return link->importedDocument();
    return 0;
}

void HTMLLinkElement::process()
{
    if (LinkResource* link = linkResourceToProcess())
        link->process();
}

Node::InsertionNotificationRequest HTMLLinkElement::insertedInto(ContainerNode* insertionPoint)
{
    HTMLElement::insertedInto(insertionPoint);
    if (!insertionPoint->inDocument())
        return InsertionDone;

    m_isInShadowTree = isInShadowTree();
    if (m_isInShadowTree)
        return InsertionDone;

    document().styleEngine()->addStyleSheetCandidateNode(this, m_createdByParser);

    process();
    return InsertionDone;
}

void HTMLLinkElement::removedFrom(ContainerNode* insertionPoint)
{
    HTMLElement::removedFrom(insertionPoint);
    if (!insertionPoint->inDocument())
        return;

    m_linkLoader.released();

    if (m_isInShadowTree) {
        ASSERT(!linkStyle() || !linkStyle()->hasSheet());
        return;
    }
    document().styleEngine()->removeStyleSheetCandidateNode(this);

    RefPtrWillBeRawPtr<StyleSheet> removedSheet = sheet();

    if (m_link)
        m_link->ownerRemoved();

    document().removedStyleSheet(removedSheet.get());
}

void HTMLLinkElement::finishParsingChildren()
{
    m_createdByParser = false;
    HTMLElement::finishParsingChildren();
}

bool HTMLLinkElement::styleSheetIsLoading() const
{
    return linkStyle() && linkStyle()->styleSheetIsLoading();
}

void HTMLLinkElement::linkLoaded()
{
    dispatchEvent(Event::create(EventTypeNames::load));
}

void HTMLLinkElement::linkLoadingErrored()
{
    dispatchEvent(Event::create(EventTypeNames::error));
}

void HTMLLinkElement::didStartLinkPrerender()
{
    dispatchEvent(Event::create(EventTypeNames::webkitprerenderstart));
}

void HTMLLinkElement::didStopLinkPrerender()
{
    dispatchEvent(Event::create(EventTypeNames::webkitprerenderstop));
}

void HTMLLinkElement::didSendLoadForLinkPrerender()
{
    dispatchEvent(Event::create(EventTypeNames::webkitprerenderload));
}

void HTMLLinkElement::didSendDOMContentLoadedForLinkPrerender()
{
    dispatchEvent(Event::create(EventTypeNames::webkitprerenderdomcontentloaded));
}

bool HTMLLinkElement::sheetLoaded()
{
    ASSERT(linkStyle());
    return linkStyle()->sheetLoaded();
}

void HTMLLinkElement::notifyLoadedSheetAndAllCriticalSubresources(bool errorOccurred)
{
    ASSERT(linkStyle());
    linkStyle()->notifyLoadedSheetAndAllCriticalSubresources(errorOccurred);
}

void HTMLLinkElement::dispatchPendingLoadEvents()
{
    linkLoadEventSender().dispatchPendingEvents();
}

void HTMLLinkElement::dispatchPendingEvent(LinkEventSender* eventSender)
{
    ASSERT_UNUSED(eventSender, eventSender == &linkLoadEventSender());
    ASSERT(m_link);
    if (m_link->hasLoaded())
        linkLoaded();
    else
        linkLoadingErrored();
}

void HTMLLinkElement::scheduleEvent()
{
    linkLoadEventSender().dispatchEventSoon(this);
}

void HTMLLinkElement::startLoadingDynamicSheet()
{
    ASSERT(linkStyle());
    linkStyle()->startLoadingDynamicSheet();
}

bool HTMLLinkElement::isURLAttribute(const Attribute& attribute) const
{
    return attribute.name().localName() == hrefAttr || HTMLElement::isURLAttribute(attribute);
}

bool HTMLLinkElement::hasLegalLinkAttribute(const QualifiedName& name) const
{
    return name == hrefAttr || HTMLElement::hasLegalLinkAttribute(name);
}

const QualifiedName& HTMLLinkElement::subResourceAttributeName() const
{
    // If the link element is not css, ignore it.
    if (equalIgnoringCase(getAttribute(typeAttr), "text/css")) {
        // FIXME: Add support for extracting links of sub-resources which
        // are inside style-sheet such as @import, @font-face, url(), etc.
        return hrefAttr;
    }
    return HTMLElement::subResourceAttributeName();
}

KURL HTMLLinkElement::href() const
{
    return document().completeURL(getAttribute(hrefAttr));
}

const AtomicString& HTMLLinkElement::rel() const
{
    return getAttribute(relAttr);
}

const AtomicString& HTMLLinkElement::type() const
{
    return getAttribute(typeAttr);
}

bool HTMLLinkElement::async() const
{
    return fastHasAttribute(HTMLNames::asyncAttr);
}

IconType HTMLLinkElement::iconType() const
{
    return m_relAttribute.iconType();
}

const Vector<IntSize>& HTMLLinkElement::iconSizes() const
{
    return m_iconSizes;
}

DOMSettableTokenList* HTMLLinkElement::sizes() const
{
    return m_sizes.get();
}

PassOwnPtr<LinkStyle> LinkStyle::create(HTMLLinkElement* owner)
{
    return adoptPtr(new LinkStyle(owner));
}

LinkStyle::LinkStyle(HTMLLinkElement* owner)
    : LinkResource(owner)
    , m_disabledState(Unset)
    , m_pendingSheetType(None)
    , m_loading(false)
    , m_firedLoad(false)
    , m_loadedSheet(false)
{
}

LinkStyle::~LinkStyle()
{
    if (m_sheet)
        m_sheet->clearOwnerNode();
}

Document& LinkStyle::document()
{
    return m_owner->document();
}

void LinkStyle::setCSSStyleSheet(const String& href, const KURL& baseURL, const String& charset, const CSSStyleSheetResource* cachedStyleSheet)
{
    if (!m_owner->inDocument()) {
        ASSERT(!m_sheet);
        return;

    }
    // Completing the sheet load may cause scripts to execute.
    RefPtr<Node> protector(m_owner);

    CSSParserContext parserContext(m_owner->document(), 0, baseURL, charset);

    if (RefPtrWillBeRawPtr<StyleSheetContents> restoredSheet = const_cast<CSSStyleSheetResource*>(cachedStyleSheet)->restoreParsedStyleSheet(parserContext)) {
        ASSERT(restoredSheet->isCacheable());
        ASSERT(!restoredSheet->isLoading());

        if (m_sheet)
            clearSheet();
        m_sheet = CSSStyleSheet::create(restoredSheet, m_owner);
        m_sheet->setMediaQueries(MediaQuerySet::create(m_owner->media()));
        m_sheet->setTitle(m_owner->title());

        m_loading = false;
        restoredSheet->checkLoaded();
        return;
    }

    RefPtrWillBeRawPtr<StyleSheetContents> styleSheet = StyleSheetContents::create(href, parserContext);

    if (m_sheet)
        clearSheet();
    m_sheet = CSSStyleSheet::create(styleSheet, m_owner);
    m_sheet->setMediaQueries(MediaQuerySet::create(m_owner->media()));
    m_sheet->setTitle(m_owner->title());

    styleSheet->parseAuthorStyleSheet(cachedStyleSheet, m_owner->document().securityOrigin());

    m_loading = false;
    styleSheet->notifyLoadedSheet(cachedStyleSheet);
    styleSheet->checkLoaded();

    if (styleSheet->isCacheable())
        const_cast<CSSStyleSheetResource*>(cachedStyleSheet)->saveParsedStyleSheet(styleSheet);
}

bool LinkStyle::sheetLoaded()
{
    if (!styleSheetIsLoading()) {
        removePendingSheet();
        return true;
    }
    return false;
}

void LinkStyle::notifyLoadedSheetAndAllCriticalSubresources(bool errorOccurred)
{
    if (m_firedLoad)
        return;
    m_loadedSheet = !errorOccurred;
    if (m_owner)
        m_owner->scheduleEvent();
    m_firedLoad = true;
}

void LinkStyle::startLoadingDynamicSheet()
{
    ASSERT(m_pendingSheetType < Blocking);
    addPendingSheet(Blocking);
}

void LinkStyle::clearSheet()
{
    ASSERT(m_sheet);
    ASSERT(m_sheet->ownerNode() == m_owner);
    m_sheet->clearOwnerNode();
    m_sheet = nullptr;
}

bool LinkStyle::styleSheetIsLoading() const
{
    if (m_loading)
        return true;
    if (!m_sheet)
        return false;
    return m_sheet->contents()->isLoading();
}

void LinkStyle::addPendingSheet(PendingSheetType type)
{
    if (type <= m_pendingSheetType)
        return;
    m_pendingSheetType = type;

    if (m_pendingSheetType == NonBlocking)
        return;
    m_owner->document().styleEngine()->addPendingSheet();
}

void LinkStyle::removePendingSheet(RemovePendingSheetNotificationType notification)
{
    PendingSheetType type = m_pendingSheetType;
    m_pendingSheetType = None;

    if (type == None)
        return;
    if (type == NonBlocking) {
        // Tell StyleEngine to re-compute styleSheets of this m_owner's treescope.
        m_owner->document().styleEngine()->modifiedStyleSheetCandidateNode(m_owner);
        // Document::removePendingSheet() triggers the style selector recalc for blocking sheets.
        // FIXME: We don't have enough knowledge at this point to know if we're adding or removing a sheet
        // so we can't call addedStyleSheet() or removedStyleSheet().
        m_owner->document().styleResolverChanged(RecalcStyleImmediately);
        return;
    }

    m_owner->document().styleEngine()->removePendingSheet(m_owner,
        notification == RemovePendingSheetNotifyImmediately
        ? StyleEngine::RemovePendingSheetNotifyImmediately
        : StyleEngine::RemovePendingSheetNotifyLater);
}

void LinkStyle::setDisabledState(bool disabled)
{
    LinkStyle::DisabledState oldDisabledState = m_disabledState;
    m_disabledState = disabled ? Disabled : EnabledViaScript;
    if (oldDisabledState != m_disabledState) {
        // If we change the disabled state while the sheet is still loading, then we have to
        // perform three checks:
        if (styleSheetIsLoading()) {
            // Check #1: The sheet becomes disabled while loading.
            if (m_disabledState == Disabled)
                removePendingSheet();

            // Check #2: An alternate sheet becomes enabled while it is still loading.
            if (m_owner->relAttribute().isAlternate() && m_disabledState == EnabledViaScript)
                addPendingSheet(Blocking);

            // Check #3: A main sheet becomes enabled while it was still loading and
            // after it was disabled via script. It takes really terrible code to make this
            // happen (a double toggle for no reason essentially). This happens on
            // virtualplastic.net, which manages to do about 12 enable/disables on only 3
            // sheets. :)
            if (!m_owner->relAttribute().isAlternate() && m_disabledState == EnabledViaScript && oldDisabledState == Disabled)
                addPendingSheet(Blocking);

            // If the sheet is already loading just bail.
            return;
        }

        if (m_sheet)
            m_sheet->setDisabled(disabled);

        // Load the sheet, since it's never been loaded before.
        if (!m_sheet && m_disabledState == EnabledViaScript) {
            if (m_owner->shouldProcessStyle())
                process();
        } else {
            // FIXME: We don't have enough knowledge here to know if we should call addedStyleSheet() or removedStyleSheet().
            m_owner->document().styleResolverChanged(RecalcStyleDeferred);
        }
    }
}

void LinkStyle::process()
{
    ASSERT(m_owner->shouldProcessStyle());
    String type = m_owner->typeValue().lower();
    LinkRequestBuilder builder(m_owner);

    if (m_owner->relAttribute().iconType() != InvalidIcon && builder.url().isValid() && !builder.url().isEmpty()) {
        if (!m_owner->shouldLoadLink())
            return;
        if (!document().securityOrigin()->canDisplay(builder.url()))
            return;
        if (!document().contentSecurityPolicy()->allowImageFromSource(builder.url()))
            return;
        if (document().frame() && document().frame()->loader().client())
            document().frame()->loader().client()->dispatchDidChangeIcons(m_owner->relAttribute().iconType());
    }

    if (!m_owner->loadLink(type, builder.url()))
        return;

    if ((m_disabledState != Disabled) && m_owner->relAttribute().isStyleSheet()
        && shouldLoadResource() && builder.url().isValid()) {

        if (resource()) {
            removePendingSheet();
            clearResource();
        }

        if (!m_owner->shouldLoadLink())
            return;

        m_loading = true;

        bool mediaQueryMatches = true;
        if (!m_owner->media().isEmpty()) {
            LocalFrame* frame = loadingFrame();
            if (Document* document = loadingFrame()->document()) {
                RefPtr<RenderStyle> documentStyle = StyleResolver::styleForDocument(*document);
                RefPtrWillBeRawPtr<MediaQuerySet> media = MediaQuerySet::create(m_owner->media());
                MediaQueryEvaluator evaluator(frame->view()->mediaType(), frame, documentStyle.get());
                mediaQueryMatches = evaluator.eval(media.get());
            }
        }

        // Don't hold up render tree construction and script execution on stylesheets
        // that are not needed for the rendering at the moment.
        bool blocking = mediaQueryMatches && !m_owner->isAlternate();
        addPendingSheet(blocking ? Blocking : NonBlocking);

        // Load stylesheets that are not needed for the rendering immediately with low priority.
        FetchRequest request = builder.build(blocking);
        AtomicString crossOriginMode = m_owner->fastGetAttribute(HTMLNames::crossoriginAttr);
        if (!crossOriginMode.isNull())
            request.setCrossOriginAccessControl(document().securityOrigin(), crossOriginMode);
        setResource(document().fetcher()->fetchCSSStyleSheet(request));

        if (!resource()) {
            // The request may have been denied if (for example) the stylesheet is local and the document is remote.
            m_loading = false;
            removePendingSheet();
        }
    } else if (m_sheet) {
        // we no longer contain a stylesheet, e.g. perhaps rel or type was changed
        RefPtrWillBeRawPtr<StyleSheet> removedSheet = m_sheet.get();
        clearSheet();
        document().removedStyleSheet(removedSheet.get());
    }
}

void LinkStyle::setSheetTitle(const String& title)
{
    if (m_sheet)
        m_sheet->setTitle(title);
}

void LinkStyle::ownerRemoved()
{
    if (m_sheet)
        clearSheet();

    if (styleSheetIsLoading())
        removePendingSheet(RemovePendingSheetNotifyLater);
}

} // namespace WebCore