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      1 /*
      2  * Copyright (C) 2013 Google Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions are
      6  * met:
      7  *
      8  *     * Redistributions of source code must retain the above copyright
      9  * notice, this list of conditions and the following disclaimer.
     10  *     * Redistributions in binary form must reproduce the above
     11  * copyright notice, this list of conditions and the following disclaimer
     12  * in the documentation and/or other materials provided with the
     13  * distribution.
     14  *     * Neither the name of Google Inc. nor the names of its
     15  * contributors may be used to endorse or promote products derived from
     16  * this software without specific prior written permission.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     29  */
     30 
     31 #include "config.h"
     32 #include "core/fetch/ResourceLoadPriorityOptimizer.h"
     33 #include "core/rendering/RenderObject.h"
     34 #include "platform/TraceEvent.h"
     35 
     36 #include "wtf/Vector.h"
     37 
     38 namespace WebCore {
     39 
     40 ResourceLoadPriorityOptimizer* ResourceLoadPriorityOptimizer::resourceLoadPriorityOptimizer()
     41 {
     42     DEFINE_STATIC_LOCAL(ResourceLoadPriorityOptimizer, s_renderLoadOptimizer, ());
     43     return &s_renderLoadOptimizer;
     44 }
     45 
     46 ResourceLoadPriorityOptimizer::ResourceAndVisibility::ResourceAndVisibility(ImageResource* image, VisibilityStatus visibilityStatus, uint32_t screenArea)
     47     : imageResource(image)
     48     , status(visibilityStatus)
     49     , screenArea(screenArea)
     50 {
     51 }
     52 
     53 ResourceLoadPriorityOptimizer::ResourceAndVisibility::~ResourceAndVisibility()
     54 {
     55 }
     56 
     57 ResourceLoadPriorityOptimizer::ResourceLoadPriorityOptimizer()
     58 {
     59 }
     60 
     61 ResourceLoadPriorityOptimizer::~ResourceLoadPriorityOptimizer()
     62 {
     63 }
     64 
     65 void ResourceLoadPriorityOptimizer::addRenderObject(RenderObject* renderer)
     66 {
     67     m_objects.add(renderer);
     68     renderer->setHasPendingResourceUpdate(true);
     69 }
     70 
     71 void ResourceLoadPriorityOptimizer::removeRenderObject(RenderObject* renderer)
     72 {
     73     if (!renderer->hasPendingResourceUpdate())
     74         return;
     75     m_objects.remove(renderer);
     76     renderer->setHasPendingResourceUpdate(false);
     77 }
     78 
     79 void ResourceLoadPriorityOptimizer::updateAllImageResourcePriorities()
     80 {
     81     TRACE_EVENT0("webkit", "ResourceLoadPriorityOptimizer::updateAllImageResourcePriorities");
     82 
     83     m_imageResources.clear();
     84 
     85     Vector<RenderObject*> objectsToRemove;
     86     for (RenderObjectSet::iterator it = m_objects.begin(); it != m_objects.end(); ++it) {
     87         RenderObject* obj = *it;
     88         if (!obj->updateImageLoadingPriorities()) {
     89             objectsToRemove.append(obj);
     90         }
     91     }
     92     m_objects.removeAll(objectsToRemove);
     93 
     94     updateImageResourcesWithLoadPriority();
     95 }
     96 
     97 void ResourceLoadPriorityOptimizer::updateImageResourcesWithLoadPriority()
     98 {
     99     for (ImageResourceMap::iterator it = m_imageResources.begin(); it != m_imageResources.end(); ++it) {
    100         ResourceLoadPriority priority = it->value->status == Visible ?
    101             ResourceLoadPriorityLow : ResourceLoadPriorityVeryLow;
    102 
    103         if (priority != it->value->imageResource->resourceRequest().priority()) {
    104             it->value->imageResource->resourceRequest().setPriority(priority, it->value->screenArea);
    105             it->value->imageResource->didChangePriority(priority, it->value->screenArea);
    106         }
    107     }
    108     m_imageResources.clear();
    109 }
    110 
    111 void ResourceLoadPriorityOptimizer::notifyImageResourceVisibility(ImageResource* img, VisibilityStatus status, const LayoutRect& screenRect)
    112 {
    113     if (!img || img->isLoaded())
    114         return;
    115 
    116     int screenArea = 0;
    117     if (!screenRect.isEmpty() && status == Visible)
    118         screenArea += static_cast<uint32_t>(screenRect.width() * screenRect.height());
    119 
    120     ImageResourceMap::AddResult result = m_imageResources.add(img->identifier(), adoptPtr(new ResourceAndVisibility(img, status, screenArea)));
    121     if (!result.isNewEntry && status == Visible) {
    122         result.storedValue->value->status = status;
    123         result.storedValue->value->screenArea = status;
    124     }
    125 }
    126 
    127 }
    128