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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  * Copyright (C) 2004, 2005, 2006, 2007, 2009, 2010 Apple Inc. All rights reserved.
      5  *
      6  * This library is free software; you can redistribute it and/or
      7  * modify it under the terms of the GNU Library General Public
      8  * License as published by the Free Software Foundation; either
      9  * version 2 of the License, or (at your option) any later version.
     10  *
     11  * This library is distributed in the hope that it will be useful,
     12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
     13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     14  * Library General Public License for more details.
     15  *
     16  * You should have received a copy of the GNU Library General Public License
     17  * along with this library; see the file COPYING.LIB.  If not, write to
     18  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
     19  * Boston, MA 02110-1301, USA.
     20  */
     21 
     22 #include "config.h"
     23 #include "ImageLoader.h"
     24 
     25 #include "CachedImage.h"
     26 #include "CachedResourceLoader.h"
     27 #include "Document.h"
     28 #include "Element.h"
     29 #include "HTMLNames.h"
     30 #include "HTMLObjectElement.h"
     31 #include "RenderImage.h"
     32 
     33 #if ENABLE(SVG)
     34 #include "RenderSVGImage.h"
     35 #endif
     36 #if ENABLE(VIDEO)
     37 #include "RenderVideo.h"
     38 #endif
     39 
     40 #if !ASSERT_DISABLED
     41 // ImageLoader objects are allocated as members of other objects, so generic pointer check would always fail.
     42 namespace WTF {
     43 
     44 template<> struct ValueCheck<WebCore::ImageLoader*> {
     45     typedef WebCore::ImageLoader* TraitType;
     46     static void checkConsistency(const WebCore::ImageLoader* p)
     47     {
     48         if (!p)
     49             return;
     50         ASSERT(p->element());
     51         ValueCheck<WebCore::Element*>::checkConsistency(p->element());
     52     }
     53 };
     54 
     55 }
     56 #endif
     57 
     58 namespace WebCore {
     59 
     60 class ImageEventSender {
     61     WTF_MAKE_NONCOPYABLE(ImageEventSender); WTF_MAKE_FAST_ALLOCATED;
     62 public:
     63     ImageEventSender(const AtomicString& eventType);
     64 
     65     void dispatchEventSoon(ImageLoader*);
     66     void cancelEvent(ImageLoader*);
     67 
     68     void dispatchPendingEvents();
     69 
     70 #if !ASSERT_DISABLED
     71     bool hasPendingEvents(ImageLoader* loader) { return m_dispatchSoonList.find(loader) != notFound; }
     72 #endif
     73 
     74 private:
     75     void timerFired(Timer<ImageEventSender>*);
     76 
     77     AtomicString m_eventType;
     78     Timer<ImageEventSender> m_timer;
     79     Vector<ImageLoader*> m_dispatchSoonList;
     80     Vector<ImageLoader*> m_dispatchingList;
     81 };
     82 
     83 static ImageEventSender& beforeLoadEventSender()
     84 {
     85     DEFINE_STATIC_LOCAL(ImageEventSender, sender, (eventNames().beforeloadEvent));
     86     return sender;
     87 }
     88 
     89 static ImageEventSender& loadEventSender()
     90 {
     91     DEFINE_STATIC_LOCAL(ImageEventSender, sender, (eventNames().loadEvent));
     92     return sender;
     93 }
     94 
     95 ImageLoader::ImageLoader(Element* element)
     96     : m_element(element)
     97     , m_image(0)
     98     , m_firedBeforeLoad(true)
     99     , m_firedLoad(true)
    100     , m_imageComplete(true)
    101     , m_loadManually(false)
    102 {
    103 }
    104 
    105 ImageLoader::~ImageLoader()
    106 {
    107     if (m_image)
    108         m_image->removeClient(this);
    109 
    110     ASSERT(!m_firedBeforeLoad || !beforeLoadEventSender().hasPendingEvents(this));
    111     if (!m_firedBeforeLoad)
    112         beforeLoadEventSender().cancelEvent(this);
    113 
    114     ASSERT(!m_firedLoad || !loadEventSender().hasPendingEvents(this));
    115     if (!m_firedLoad)
    116         loadEventSender().cancelEvent(this);
    117 }
    118 
    119 void ImageLoader::setImage(CachedImage* newImage)
    120 {
    121     ASSERT(m_failedLoadURL.isEmpty());
    122     CachedImage* oldImage = m_image.get();
    123     if (newImage != oldImage) {
    124         m_image = newImage;
    125         if (!m_firedBeforeLoad) {
    126             beforeLoadEventSender().cancelEvent(this);
    127             m_firedBeforeLoad = true;
    128         }
    129         if (!m_firedLoad) {
    130             loadEventSender().cancelEvent(this);
    131             m_firedLoad = true;
    132         }
    133         m_imageComplete = true;
    134         if (newImage)
    135             newImage->addClient(this);
    136         if (oldImage)
    137             oldImage->removeClient(this);
    138     }
    139 
    140     if (RenderImageResource* imageResource = renderImageResource())
    141         imageResource->resetAnimation();
    142 }
    143 
    144 void ImageLoader::updateFromElement()
    145 {
    146     // If we're not making renderers for the page, then don't load images.  We don't want to slow
    147     // down the raw HTML parsing case by loading images we don't intend to display.
    148     Document* document = m_element->document();
    149     if (!document->renderer())
    150         return;
    151 
    152     AtomicString attr = m_element->getAttribute(m_element->imageSourceAttributeName());
    153 
    154     if (attr == m_failedLoadURL)
    155         return;
    156 
    157     // Do not load any image if the 'src' attribute is missing or if it is
    158     // an empty string referring to a local file. The latter condition is
    159     // a quirk that preserves old behavior that Dashboard widgets
    160     // need (<rdar://problem/5994621>).
    161     CachedImage* newImage = 0;
    162     if (!(attr.isNull() || (attr.isEmpty() && document->baseURI().isLocalFile()))) {
    163         if (m_loadManually) {
    164             bool autoLoadOtherImages = document->cachedResourceLoader()->autoLoadImages();
    165             document->cachedResourceLoader()->setAutoLoadImages(false);
    166             newImage = new CachedImage(sourceURI(attr));
    167             newImage->setLoading(true);
    168             newImage->setOwningCachedResourceLoader(document->cachedResourceLoader());
    169             document->cachedResourceLoader()->m_documentResources.set(newImage->url(), newImage);
    170             document->cachedResourceLoader()->setAutoLoadImages(autoLoadOtherImages);
    171         } else
    172             newImage = document->cachedResourceLoader()->requestImage(sourceURI(attr));
    173 
    174         // If we do not have an image here, it means that a cross-site
    175         // violation occurred.
    176         m_failedLoadURL = !newImage ? attr : AtomicString();
    177     }
    178 
    179     CachedImage* oldImage = m_image.get();
    180     if (newImage != oldImage) {
    181         if (!m_firedBeforeLoad)
    182             beforeLoadEventSender().cancelEvent(this);
    183         if (!m_firedLoad)
    184             loadEventSender().cancelEvent(this);
    185 
    186         m_image = newImage;
    187         m_firedBeforeLoad = !newImage;
    188         m_firedLoad = !newImage;
    189         m_imageComplete = !newImage;
    190 
    191         if (newImage) {
    192             newImage->addClient(this);
    193             if (!m_element->document()->hasListenerType(Document::BEFORELOAD_LISTENER))
    194                 dispatchPendingBeforeLoadEvent();
    195             else
    196                 beforeLoadEventSender().dispatchEventSoon(this);
    197         }
    198         if (oldImage)
    199             oldImage->removeClient(this);
    200     }
    201 
    202     if (RenderImageResource* imageResource = renderImageResource())
    203         imageResource->resetAnimation();
    204 }
    205 
    206 void ImageLoader::updateFromElementIgnoringPreviousError()
    207 {
    208     // Clear previous error.
    209     m_failedLoadURL = AtomicString();
    210     updateFromElement();
    211 }
    212 
    213 void ImageLoader::notifyFinished(CachedResource*)
    214 {
    215     ASSERT(m_failedLoadURL.isEmpty());
    216 
    217     m_imageComplete = true;
    218     if (haveFiredBeforeLoadEvent())
    219         updateRenderer();
    220 
    221     if (m_firedLoad)
    222         return;
    223 
    224     loadEventSender().dispatchEventSoon(this);
    225 }
    226 
    227 RenderImageResource* ImageLoader::renderImageResource()
    228 {
    229     RenderObject* renderer = m_element->renderer();
    230 
    231     if (!renderer)
    232         return 0;
    233 
    234     if (renderer->isImage())
    235         return toRenderImage(renderer)->imageResource();
    236 
    237 #if ENABLE(SVG)
    238     if (renderer->isSVGImage())
    239         return toRenderSVGImage(renderer)->imageResource();
    240 #endif
    241 
    242 #if ENABLE(VIDEO)
    243     if (renderer->isVideo())
    244         return toRenderVideo(renderer)->imageResource();
    245 #endif
    246 
    247     return 0;
    248 }
    249 
    250 void ImageLoader::updateRenderer()
    251 {
    252     RenderImageResource* imageResource = renderImageResource();
    253 
    254     if (!imageResource)
    255         return;
    256 
    257     // Only update the renderer if it doesn't have an image or if what we have
    258     // is a complete image.  This prevents flickering in the case where a dynamic
    259     // change is happening between two images.
    260     CachedImage* cachedImage = imageResource->cachedImage();
    261     if (m_image != cachedImage && (m_imageComplete || !cachedImage))
    262         imageResource->setCachedImage(m_image.get());
    263 }
    264 
    265 void ImageLoader::dispatchPendingBeforeLoadEvent()
    266 {
    267     if (m_firedBeforeLoad)
    268         return;
    269     if (!m_image)
    270         return;
    271     if (!m_element->document()->attached())
    272         return;
    273     m_firedBeforeLoad = true;
    274     if (m_element->dispatchBeforeLoadEvent(m_image->url())) {
    275         updateRenderer();
    276         return;
    277     }
    278     if (m_image) {
    279         m_image->removeClient(this);
    280         m_image = 0;
    281     }
    282     loadEventSender().cancelEvent(this);
    283 
    284     if (m_element->hasTagName(HTMLNames::objectTag))
    285         static_cast<HTMLObjectElement*>(m_element)->renderFallbackContent();
    286 }
    287 
    288 void ImageLoader::dispatchPendingLoadEvent()
    289 {
    290     if (m_firedLoad)
    291         return;
    292     if (!m_image)
    293         return;
    294     if (!m_element->document()->attached())
    295         return;
    296     m_firedLoad = true;
    297     dispatchLoadEvent();
    298 }
    299 
    300 void ImageLoader::dispatchPendingBeforeLoadEvents()
    301 {
    302     beforeLoadEventSender().dispatchPendingEvents();
    303 }
    304 
    305 void ImageLoader::dispatchPendingLoadEvents()
    306 {
    307     loadEventSender().dispatchPendingEvents();
    308 }
    309 
    310 void ImageLoader::elementWillMoveToNewOwnerDocument()
    311 {
    312     setImage(0);
    313 }
    314 
    315 ImageEventSender::ImageEventSender(const AtomicString& eventType)
    316     : m_eventType(eventType)
    317     , m_timer(this, &ImageEventSender::timerFired)
    318 {
    319 }
    320 
    321 void ImageEventSender::dispatchEventSoon(ImageLoader* loader)
    322 {
    323     m_dispatchSoonList.append(loader);
    324     if (!m_timer.isActive())
    325         m_timer.startOneShot(0);
    326 }
    327 
    328 void ImageEventSender::cancelEvent(ImageLoader* loader)
    329 {
    330     // Remove instances of this loader from both lists.
    331     // Use loops because we allow multiple instances to get into the lists.
    332     size_t size = m_dispatchSoonList.size();
    333     for (size_t i = 0; i < size; ++i) {
    334         if (m_dispatchSoonList[i] == loader)
    335             m_dispatchSoonList[i] = 0;
    336     }
    337     size = m_dispatchingList.size();
    338     for (size_t i = 0; i < size; ++i) {
    339         if (m_dispatchingList[i] == loader)
    340             m_dispatchingList[i] = 0;
    341     }
    342     if (m_dispatchSoonList.isEmpty())
    343         m_timer.stop();
    344 }
    345 
    346 void ImageEventSender::dispatchPendingEvents()
    347 {
    348     // Need to avoid re-entering this function; if new dispatches are
    349     // scheduled before the parent finishes processing the list, they
    350     // will set a timer and eventually be processed.
    351     if (!m_dispatchingList.isEmpty())
    352         return;
    353 
    354     m_timer.stop();
    355 
    356     m_dispatchSoonList.checkConsistency();
    357 
    358     m_dispatchingList.swap(m_dispatchSoonList);
    359     size_t size = m_dispatchingList.size();
    360     for (size_t i = 0; i < size; ++i) {
    361         if (ImageLoader* loader = m_dispatchingList[i]) {
    362             if (m_eventType == eventNames().beforeloadEvent)
    363                 loader->dispatchPendingBeforeLoadEvent();
    364             else
    365                 loader->dispatchPendingLoadEvent();
    366         }
    367     }
    368     m_dispatchingList.clear();
    369 }
    370 
    371 void ImageEventSender::timerFired(Timer<ImageEventSender>*)
    372 {
    373     dispatchPendingEvents();
    374 }
    375 
    376 }
    377