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      1 /*
      2  * Copyright (C) 1999 Lars Knoll (knoll (at) kde.org)
      3  *           (C) 1999 Antti Koivisto (koivisto (at) kde.org)
      4  *           (C) 2001 Dirk Mueller (mueller (at) kde.org)
      5  * Copyright (C) 2003, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
      6  * Copyright (C) 2009 Rob Buis (rwlbuis (at) gmail.com)
      7  *
      8  * This library is free software; you can redistribute it and/or
      9  * modify it under the terms of the GNU Library General Public
     10  * License as published by the Free Software Foundation; either
     11  * version 2 of the License, or (at your option) any later version.
     12  *
     13  * This library is distributed in the hope that it will be useful,
     14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
     15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     16  * Library General Public License for more details.
     17  *
     18  * You should have received a copy of the GNU Library General Public License
     19  * along with this library; see the file COPYING.LIB.  If not, write to
     20  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
     21  * Boston, MA 02110-1301, USA.
     22  */
     23 
     24 #include "config.h"
     25 #include "HTMLLinkElement.h"
     26 
     27 #include "Attribute.h"
     28 #include "CachedCSSStyleSheet.h"
     29 #include "CachedResource.h"
     30 #include "CachedResourceLoader.h"
     31 #include "CSSStyleSelector.h"
     32 #include "Document.h"
     33 #include "Frame.h"
     34 #include "FrameLoader.h"
     35 #include "FrameLoaderClient.h"
     36 #include "FrameTree.h"
     37 #include "FrameView.h"
     38 #include "HTMLNames.h"
     39 #include "HTMLParserIdioms.h"
     40 #include "MediaList.h"
     41 #include "MediaQueryEvaluator.h"
     42 #include "Page.h"
     43 #include "ResourceHandle.h"
     44 #include "ScriptEventListener.h"
     45 #include "Settings.h"
     46 #include <wtf/StdLibExtras.h>
     47 
     48 namespace WebCore {
     49 
     50 using namespace HTMLNames;
     51 
     52 inline HTMLLinkElement::HTMLLinkElement(const QualifiedName& tagName, Document* document, bool createdByParser)
     53     : HTMLElement(tagName, document)
     54 #if ENABLE(LINK_PREFETCH)
     55     , m_onloadTimer(this, &HTMLLinkElement::onloadTimerFired)
     56 #endif
     57     , m_disabledState(Unset)
     58     , m_loading(false)
     59     , m_createdByParser(createdByParser)
     60     , m_isInShadowTree(false)
     61     , m_pendingSheetType(None)
     62 {
     63     ASSERT(hasTagName(linkTag));
     64 }
     65 
     66 PassRefPtr<HTMLLinkElement> HTMLLinkElement::create(const QualifiedName& tagName, Document* document, bool createdByParser)
     67 {
     68     return adoptRef(new HTMLLinkElement(tagName, document, createdByParser));
     69 }
     70 
     71 HTMLLinkElement::~HTMLLinkElement()
     72 {
     73     if (m_sheet)
     74         m_sheet->clearOwnerNode();
     75 
     76     if (m_cachedSheet) {
     77         m_cachedSheet->removeClient(this);
     78         removePendingSheet();
     79     }
     80 
     81 #if ENABLE(LINK_PREFETCH)
     82     if (m_cachedLinkResource)
     83         m_cachedLinkResource->removeClient(this);
     84 #endif
     85 }
     86 
     87 void HTMLLinkElement::setDisabledState(bool _disabled)
     88 {
     89     DisabledState oldDisabledState = m_disabledState;
     90     m_disabledState = _disabled ? Disabled : EnabledViaScript;
     91     if (oldDisabledState != m_disabledState) {
     92         // If we change the disabled state while the sheet is still loading, then we have to
     93         // perform three checks:
     94         if (isLoading()) {
     95             // Check #1: The sheet becomes disabled while loading.
     96             if (m_disabledState == Disabled)
     97                 removePendingSheet();
     98 
     99             // Check #2: An alternate sheet becomes enabled while it is still loading.
    100             if (m_relAttribute.m_isAlternate && m_disabledState == EnabledViaScript)
    101                 addPendingSheet(Blocking);
    102 
    103             // Check #3: A main sheet becomes enabled while it was still loading and
    104             // after it was disabled via script.  It takes really terrible code to make this
    105             // happen (a double toggle for no reason essentially).  This happens on
    106             // virtualplastic.net, which manages to do about 12 enable/disables on only 3
    107             // sheets. :)
    108             if (!m_relAttribute.m_isAlternate && m_disabledState == EnabledViaScript && oldDisabledState == Disabled)
    109                 addPendingSheet(Blocking);
    110 
    111             // If the sheet is already loading just bail.
    112             return;
    113         }
    114 
    115         // Load the sheet, since it's never been loaded before.
    116         if (!m_sheet && m_disabledState == EnabledViaScript)
    117             process();
    118         else
    119             document()->styleSelectorChanged(DeferRecalcStyle); // Update the style selector.
    120     }
    121 }
    122 
    123 StyleSheet* HTMLLinkElement::sheet() const
    124 {
    125     return m_sheet.get();
    126 }
    127 
    128 void HTMLLinkElement::parseMappedAttribute(Attribute* attr)
    129 {
    130     if (attr->name() == relAttr) {
    131         tokenizeRelAttribute(attr->value(), m_relAttribute);
    132         process();
    133     } else if (attr->name() == hrefAttr) {
    134         m_url = document()->completeURL(stripLeadingAndTrailingHTMLSpaces(attr->value()));
    135         process();
    136     } else if (attr->name() == typeAttr) {
    137         m_type = attr->value();
    138         process();
    139     } else if (attr->name() == mediaAttr) {
    140         m_media = attr->value().string().lower();
    141         process();
    142     } else if (attr->name() == disabledAttr)
    143         setDisabledState(!attr->isNull());
    144     else if (attr->name() == onbeforeloadAttr)
    145         setAttributeEventListener(eventNames().beforeloadEvent, createAttributeEventListener(this, attr));
    146 #if ENABLE(LINK_PREFETCH)
    147     else if (attr->name() == onloadAttr)
    148         setAttributeEventListener(eventNames().loadEvent, createAttributeEventListener(this, attr));
    149     else if (attr->name() == onerrorAttr)
    150         setAttributeEventListener(eventNames().errorEvent, createAttributeEventListener(this, attr));
    151 #endif
    152     else {
    153         if (attr->name() == titleAttr && m_sheet)
    154             m_sheet->setTitle(attr->value());
    155         HTMLElement::parseMappedAttribute(attr);
    156     }
    157 }
    158 
    159 void HTMLLinkElement::tokenizeRelAttribute(const AtomicString& rel, RelAttribute& relAttribute)
    160 {
    161     relAttribute.m_isStyleSheet = false;
    162     relAttribute.m_isIcon = false;
    163     relAttribute.m_isAlternate = false;
    164     relAttribute.m_isDNSPrefetch = false;
    165 #if ENABLE(LINK_PREFETCH)
    166     relAttribute.m_isLinkPrefetch = false;
    167     relAttribute.m_isLinkSubresource = false;
    168 #endif
    169 #ifdef ANDROID_APPLE_TOUCH_ICON
    170     relAttribute.m_isTouchIcon = false;
    171     relAttribute.m_isPrecomposedTouchIcon = false;
    172 #endif
    173     if (equalIgnoringCase(rel, "stylesheet"))
    174         relAttribute.m_isStyleSheet = true;
    175     else if (equalIgnoringCase(rel, "icon") || equalIgnoringCase(rel, "shortcut icon"))
    176         relAttribute.m_isIcon = true;
    177 #ifdef ANDROID_APPLE_TOUCH_ICON
    178     else if (equalIgnoringCase(rel, "apple-touch-icon"))
    179         relAttribute.m_isTouchIcon = true;
    180     else if (equalIgnoringCase(rel, "apple-touch-icon-precomposed"))
    181         relAttribute.m_isPrecomposedTouchIcon = true;
    182 #endif
    183     else if (equalIgnoringCase(rel, "dns-prefetch"))
    184         relAttribute.m_isDNSPrefetch = true;
    185     else if (equalIgnoringCase(rel, "alternate stylesheet") || equalIgnoringCase(rel, "stylesheet alternate")) {
    186         relAttribute.m_isStyleSheet = true;
    187         relAttribute.m_isAlternate = true;
    188     } else {
    189         // Tokenize the rel attribute and set bits based on specific keywords that we find.
    190         String relString = rel.string();
    191         relString.replace('\n', ' ');
    192         Vector<String> list;
    193         relString.split(' ', list);
    194         Vector<String>::const_iterator end = list.end();
    195         for (Vector<String>::const_iterator it = list.begin(); it != end; ++it) {
    196             if (equalIgnoringCase(*it, "stylesheet"))
    197                 relAttribute.m_isStyleSheet = true;
    198             else if (equalIgnoringCase(*it, "alternate"))
    199                 relAttribute.m_isAlternate = true;
    200             else if (equalIgnoringCase(*it, "icon"))
    201                 relAttribute.m_isIcon = true;
    202 #if ENABLE(LINK_PREFETCH)
    203             else if (equalIgnoringCase(*it, "prefetch"))
    204               relAttribute.m_isLinkPrefetch = true;
    205             else if (equalIgnoringCase(*it, "subresource"))
    206               relAttribute.m_isLinkSubresource = true;
    207 #endif
    208         }
    209     }
    210 }
    211 
    212 bool HTMLLinkElement::checkBeforeLoadEvent()
    213 {
    214     RefPtr<Document> originalDocument = document();
    215     if (!dispatchBeforeLoadEvent(m_url))
    216         return false;
    217     // A beforeload handler might have removed us from the document or changed the document.
    218     if (!inDocument() || document() != originalDocument)
    219         return false;
    220     return true;
    221 }
    222 
    223 void HTMLLinkElement::process()
    224 {
    225     if (!inDocument() || m_isInShadowTree) {
    226         ASSERT(!m_sheet);
    227         return;
    228     }
    229 
    230     String type = m_type.lower();
    231 
    232     // IE extension: location of small icon for locationbar / bookmarks
    233     // We'll record this URL per document, even if we later only use it in top level frames
    234     if (m_relAttribute.m_isIcon && m_url.isValid() && !m_url.isEmpty()) {
    235         if (!checkBeforeLoadEvent())
    236             return;
    237         document()->setIconURL(m_url.string(), type);
    238     }
    239 
    240 #ifdef ANDROID_APPLE_TOUCH_ICON
    241     if ((m_relAttribute.m_isTouchIcon || m_relAttribute.m_isPrecomposedTouchIcon) && m_url.isValid()
    242         && !m_url.isEmpty() && document()->frame())
    243         document()->frame()->loader()->client()
    244                 ->dispatchDidReceiveTouchIconURL(m_url.string(),
    245                         m_relAttribute.m_isPrecomposedTouchIcon);
    246 #endif
    247 
    248     if (m_relAttribute.m_isDNSPrefetch) {
    249         Settings* settings = document()->settings();
    250         // FIXME: The href attribute of the link element can be in "//hostname" form, and we shouldn't attempt
    251         // to complete that as URL <https://bugs.webkit.org/show_bug.cgi?id=48857>.
    252         if (settings && settings->dnsPrefetchingEnabled() && m_url.isValid() && !m_url.isEmpty())
    253             ResourceHandle::prepareForURL(m_url);
    254     }
    255 
    256 #if ENABLE(LINK_PREFETCH)
    257     if ((m_relAttribute.m_isLinkPrefetch || m_relAttribute.m_isLinkSubresource) && m_url.isValid() && document()->frame()) {
    258         if (!checkBeforeLoadEvent())
    259             return;
    260         ResourceLoadPriority priority = ResourceLoadPriorityUnresolved;
    261         if (m_relAttribute.m_isLinkSubresource)
    262             priority = ResourceLoadPriorityLow;
    263 
    264         m_cachedLinkResource = document()->cachedResourceLoader()->requestLinkResource(m_url, priority);
    265         if (m_cachedLinkResource)
    266             m_cachedLinkResource->addClient(this);
    267     }
    268 #endif
    269 
    270     bool acceptIfTypeContainsTextCSS = document()->page() && document()->page()->settings() && document()->page()->settings()->treatsAnyTextCSSLinkAsStylesheet();
    271 
    272     if (m_disabledState != Disabled && (m_relAttribute.m_isStyleSheet || (acceptIfTypeContainsTextCSS && type.contains("text/css")))
    273         && document()->frame() && m_url.isValid()) {
    274 
    275         String charset = getAttribute(charsetAttr);
    276         if (charset.isEmpty() && document()->frame())
    277             charset = document()->charset();
    278 
    279         if (m_cachedSheet) {
    280             removePendingSheet();
    281             m_cachedSheet->removeClient(this);
    282             m_cachedSheet = 0;
    283         }
    284 
    285         if (!checkBeforeLoadEvent())
    286             return;
    287 
    288         m_loading = true;
    289 
    290         bool mediaQueryMatches = true;
    291         if (!m_media.isEmpty()) {
    292             RefPtr<RenderStyle> documentStyle = CSSStyleSelector::styleForDocument(document());
    293             RefPtr<MediaList> media = MediaList::createAllowingDescriptionSyntax(m_media);
    294             MediaQueryEvaluator evaluator(document()->frame()->view()->mediaType(), document()->frame(), documentStyle.get());
    295             mediaQueryMatches = evaluator.eval(media.get());
    296         }
    297 
    298         // Don't hold up render tree construction and script execution on stylesheets
    299         // that are not needed for the rendering at the moment.
    300         bool blocking = mediaQueryMatches && !isAlternate();
    301         addPendingSheet(blocking ? Blocking : NonBlocking);
    302 
    303         // Load stylesheets that are not needed for the rendering immediately with low priority.
    304         ResourceLoadPriority priority = blocking ? ResourceLoadPriorityUnresolved : ResourceLoadPriorityVeryLow;
    305         m_cachedSheet = document()->cachedResourceLoader()->requestCSSStyleSheet(m_url, charset, priority);
    306 
    307         if (m_cachedSheet)
    308             m_cachedSheet->addClient(this);
    309         else {
    310             // The request may have been denied if (for example) the stylesheet is local and the document is remote.
    311             m_loading = false;
    312             removePendingSheet();
    313         }
    314     } else if (m_sheet) {
    315         // we no longer contain a stylesheet, e.g. perhaps rel or type was changed
    316         m_sheet = 0;
    317         document()->styleSelectorChanged(DeferRecalcStyle);
    318     }
    319 }
    320 
    321 void HTMLLinkElement::insertedIntoDocument()
    322 {
    323     HTMLElement::insertedIntoDocument();
    324 
    325     m_isInShadowTree = isInShadowTree();
    326     if (m_isInShadowTree)
    327         return;
    328 
    329     document()->addStyleSheetCandidateNode(this, m_createdByParser);
    330 
    331     process();
    332 }
    333 
    334 void HTMLLinkElement::removedFromDocument()
    335 {
    336     HTMLElement::removedFromDocument();
    337 
    338     if (m_isInShadowTree) {
    339         ASSERT(!m_sheet);
    340         return;
    341     }
    342     document()->removeStyleSheetCandidateNode(this);
    343 
    344     if (m_sheet) {
    345         ASSERT(m_sheet->ownerNode() == this);
    346         m_sheet->clearOwnerNode();
    347         m_sheet = 0;
    348     }
    349 
    350     if (document()->renderer())
    351         document()->styleSelectorChanged(DeferRecalcStyle);
    352 }
    353 
    354 void HTMLLinkElement::finishParsingChildren()
    355 {
    356     m_createdByParser = false;
    357     HTMLElement::finishParsingChildren();
    358 }
    359 
    360 void HTMLLinkElement::setCSSStyleSheet(const String& href, const KURL& baseURL, const String& charset, const CachedCSSStyleSheet* sheet)
    361 {
    362     if (!inDocument()) {
    363         ASSERT(!m_sheet);
    364         return;
    365     }
    366 
    367     m_sheet = CSSStyleSheet::create(this, href, baseURL, charset);
    368 
    369     bool strictParsing = !document()->inQuirksMode();
    370     bool enforceMIMEType = strictParsing;
    371     bool crossOriginCSS = false;
    372     bool validMIMEType = false;
    373     bool needsSiteSpecificQuirks = document()->page() && document()->page()->settings()->needsSiteSpecificQuirks();
    374 
    375     // Check to see if we should enforce the MIME type of the CSS resource in strict mode.
    376     // Running in iWeb 2 is one example of where we don't want to - <rdar://problem/6099748>
    377     if (enforceMIMEType && document()->page() && !document()->page()->settings()->enforceCSSMIMETypeInNoQuirksMode())
    378         enforceMIMEType = false;
    379 
    380 #if defined(BUILDING_ON_TIGER) || defined(BUILDING_ON_LEOPARD)
    381     if (enforceMIMEType && needsSiteSpecificQuirks) {
    382         // Covers both http and https, with or without "www."
    383         if (baseURL.string().contains("mcafee.com/japan/", false))
    384             enforceMIMEType = false;
    385     }
    386 #endif
    387 
    388     String sheetText = sheet->sheetText(enforceMIMEType, &validMIMEType);
    389     m_sheet->parseString(sheetText, strictParsing);
    390 
    391     // If we're loading a stylesheet cross-origin, and the MIME type is not
    392     // standard, require the CSS to at least start with a syntactically
    393     // valid CSS rule.
    394     // This prevents an attacker playing games by injecting CSS strings into
    395     // HTML, XML, JSON, etc. etc.
    396     if (!document()->securityOrigin()->canRequest(baseURL))
    397         crossOriginCSS = true;
    398 
    399     if (crossOriginCSS && !validMIMEType && !m_sheet->hasSyntacticallyValidCSSHeader())
    400         m_sheet = CSSStyleSheet::create(this, href, baseURL, charset);
    401 
    402     if (strictParsing && needsSiteSpecificQuirks) {
    403         // Work around <https://bugs.webkit.org/show_bug.cgi?id=28350>.
    404         DEFINE_STATIC_LOCAL(const String, slashKHTMLFixesDotCss, ("/KHTMLFixes.css"));
    405         DEFINE_STATIC_LOCAL(const String, mediaWikiKHTMLFixesStyleSheet, ("/* KHTML fix stylesheet */\n/* work around the horizontal scrollbars */\n#column-content { margin-left: 0; }\n\n"));
    406         // There are two variants of KHTMLFixes.css. One is equal to mediaWikiKHTMLFixesStyleSheet,
    407         // while the other lacks the second trailing newline.
    408         if (baseURL.string().endsWith(slashKHTMLFixesDotCss) && !sheetText.isNull() && mediaWikiKHTMLFixesStyleSheet.startsWith(sheetText)
    409                 && sheetText.length() >= mediaWikiKHTMLFixesStyleSheet.length() - 1) {
    410             ASSERT(m_sheet->length() == 1);
    411             ExceptionCode ec;
    412             m_sheet->deleteRule(0, ec);
    413         }
    414     }
    415 
    416     m_sheet->setTitle(title());
    417 
    418     RefPtr<MediaList> media = MediaList::createAllowingDescriptionSyntax(m_media);
    419     m_sheet->setMedia(media.get());
    420 
    421     m_loading = false;
    422     m_sheet->checkLoaded();
    423 }
    424 
    425 bool HTMLLinkElement::isLoading() const
    426 {
    427     if (m_loading)
    428         return true;
    429     if (!m_sheet)
    430         return false;
    431     return static_cast<CSSStyleSheet *>(m_sheet.get())->isLoading();
    432 }
    433 
    434 #if ENABLE(LINK_PREFETCH)
    435 void HTMLLinkElement::onloadTimerFired(Timer<HTMLLinkElement>* timer)
    436 {
    437     ASSERT_UNUSED(timer, timer == &m_onloadTimer);
    438     if (m_cachedLinkResource->errorOccurred())
    439         dispatchEvent(Event::create(eventNames().errorEvent, false, false));
    440     else
    441         dispatchEvent(Event::create(eventNames().loadEvent, false, false));
    442 
    443     m_cachedLinkResource->removeClient(this);
    444     m_cachedLinkResource = 0;
    445 }
    446 
    447 void HTMLLinkElement::notifyFinished(CachedResource* resource)
    448 {
    449     m_onloadTimer.startOneShot(0);
    450     ASSERT(m_cachedLinkResource.get() == resource);
    451 }
    452 #endif
    453 
    454 bool HTMLLinkElement::sheetLoaded()
    455 {
    456     if (!isLoading()) {
    457         removePendingSheet();
    458         return true;
    459     }
    460     return false;
    461 }
    462 
    463 bool HTMLLinkElement::isURLAttribute(Attribute *attr) const
    464 {
    465     return attr->name() == hrefAttr;
    466 }
    467 
    468 KURL HTMLLinkElement::href() const
    469 {
    470     return document()->completeURL(getAttribute(hrefAttr));
    471 }
    472 
    473 String HTMLLinkElement::rel() const
    474 {
    475     return getAttribute(relAttr);
    476 }
    477 
    478 String HTMLLinkElement::target() const
    479 {
    480     return getAttribute(targetAttr);
    481 }
    482 
    483 String HTMLLinkElement::type() const
    484 {
    485     return getAttribute(typeAttr);
    486 }
    487 
    488 void HTMLLinkElement::addSubresourceAttributeURLs(ListHashSet<KURL>& urls) const
    489 {
    490     HTMLElement::addSubresourceAttributeURLs(urls);
    491 
    492     // Favicons are handled by a special case in LegacyWebArchive::create()
    493     if (m_relAttribute.m_isIcon)
    494         return;
    495 
    496     if (!m_relAttribute.m_isStyleSheet)
    497         return;
    498 
    499     // Append the URL of this link element.
    500     addSubresourceURL(urls, href());
    501 
    502     // Walk the URLs linked by the linked-to stylesheet.
    503     if (StyleSheet* styleSheet = const_cast<HTMLLinkElement*>(this)->sheet())
    504         styleSheet->addSubresourceStyleURLs(urls);
    505 }
    506 
    507 void HTMLLinkElement::addPendingSheet(PendingSheetType type)
    508 {
    509     if (type <= m_pendingSheetType)
    510         return;
    511     m_pendingSheetType = type;
    512 
    513     if (m_pendingSheetType == NonBlocking)
    514         return;
    515     document()->addPendingSheet();
    516 }
    517 
    518 void HTMLLinkElement::removePendingSheet()
    519 {
    520     PendingSheetType type = m_pendingSheetType;
    521     m_pendingSheetType = None;
    522 
    523     if (type == None)
    524         return;
    525     if (type == NonBlocking) {
    526         // Document::removePendingSheet() triggers the style selector recalc for blocking sheets.
    527         document()->styleSelectorChanged(RecalcStyleImmediately);
    528         return;
    529     }
    530     document()->removePendingSheet();
    531 }
    532 
    533 }
    534