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      1 /*
      2  * Copyright (C) 1999 Lars Knoll (knoll (at) kde.org)
      3  *           (C) 2004-2005 Allan Sandfeld Jensen (kde (at) carewolf.com)
      4  * Copyright (C) 2006, 2007 Nicholas Shanks (webkit (at) nickshanks.com)
      5  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
      6  * Copyright (C) 2007 Alexey Proskuryakov <ap (at) webkit.org>
      7  * Copyright (C) 2007, 2008 Eric Seidel <eric (at) webkit.org>
      8  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
      9  * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
     10  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
     11  * Copyright (C) 2012 Google Inc. All rights reserved.
     12  *
     13  * This library is free software; you can redistribute it and/or
     14  * modify it under the terms of the GNU Library General Public
     15  * License as published by the Free Software Foundation; either
     16  * version 2 of the License, or (at your option) any later version.
     17  *
     18  * This library is distributed in the hope that it will be useful,
     19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
     20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     21  * Library General Public License for more details.
     22  *
     23  * You should have received a copy of the GNU Library General Public License
     24  * along with this library; see the file COPYING.LIB.  If not, write to
     25  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
     26  * Boston, MA 02110-1301, USA.
     27  */
     28 
     29 #include "config.h"
     30 #include "core/dom/VisitedLinkState.h"
     31 
     32 #include "core/HTMLNames.h"
     33 #include "core/XLinkNames.h"
     34 #include "core/dom/ElementTraversal.h"
     35 #include "core/html/HTMLAnchorElement.h"
     36 #include "public/platform/Platform.h"
     37 
     38 namespace WebCore {
     39 
     40 static inline const AtomicString& linkAttribute(const Element& element)
     41 {
     42     ASSERT(element.isLink());
     43     if (element.isHTMLElement())
     44         return element.fastGetAttribute(HTMLNames::hrefAttr);
     45     ASSERT(element.isSVGElement());
     46     return element.getAttribute(XLinkNames::hrefAttr);
     47 }
     48 
     49 static inline LinkHash linkHashForElement(const Element& element, const AtomicString& attribute = AtomicString())
     50 {
     51     ASSERT(attribute.isNull() || linkAttribute(element) == attribute);
     52     if (isHTMLAnchorElement(element))
     53         return toHTMLAnchorElement(element).visitedLinkHash();
     54     return visitedLinkHash(element.document().baseURL(), attribute.isNull() ? linkAttribute(element) : attribute);
     55 }
     56 
     57 VisitedLinkState::VisitedLinkState(const Document& document)
     58     : m_document(document)
     59 {
     60 }
     61 
     62 void VisitedLinkState::invalidateStyleForAllLinks()
     63 {
     64     if (m_linksCheckedForVisitedState.isEmpty())
     65         return;
     66     for (Element* element = ElementTraversal::firstWithin(m_document); element; element = ElementTraversal::next(*element)) {
     67         if (element->isLink())
     68             element->setNeedsStyleRecalc(SubtreeStyleChange);
     69     }
     70 }
     71 
     72 void VisitedLinkState::invalidateStyleForLink(LinkHash linkHash)
     73 {
     74     if (!m_linksCheckedForVisitedState.contains(linkHash))
     75         return;
     76     for (Element* element = ElementTraversal::firstWithin(m_document); element; element = ElementTraversal::next(*element)) {
     77         if (element->isLink() && linkHashForElement(*element) == linkHash)
     78             element->setNeedsStyleRecalc(SubtreeStyleChange);
     79     }
     80 }
     81 
     82 EInsideLink VisitedLinkState::determineLinkStateSlowCase(const Element& element)
     83 {
     84     ASSERT(element.isLink());
     85     ASSERT(m_document.isActive());
     86     ASSERT(m_document == element.document());
     87 
     88     const AtomicString& attribute = linkAttribute(element);
     89 
     90     if (attribute.isNull())
     91         return NotInsideLink; // This can happen for <img usemap>
     92 
     93     // An empty attribute refers to the document itself which is always
     94     // visited. It is useful to check this explicitly so that visited
     95     // links can be tested in platform independent manner, without
     96     // explicit support in the test harness.
     97     if (attribute.isEmpty())
     98         return InsideVisitedLink;
     99 
    100     if (LinkHash hash = linkHashForElement(element, attribute)) {
    101         m_linksCheckedForVisitedState.add(hash);
    102         if (blink::Platform::current()->isLinkVisited(hash))
    103             return InsideVisitedLink;
    104     }
    105 
    106     return InsideUnvisitedLink;
    107 }
    108 
    109 }
    110