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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 #ifndef ResourceLoadPriorityOptimizer_h
     32 #define ResourceLoadPriorityOptimizer_h
     33 
     34 #include "core/fetch/ImageResource.h"
     35 #include "core/fetch/ResourcePtr.h"
     36 #include "platform/geometry/LayoutRect.h"
     37 
     38 #include "wtf/HashMap.h"
     39 #include "wtf/HashSet.h"
     40 #include "wtf/OwnPtr.h"
     41 
     42 namespace WebCore {
     43 
     44 class ResourceLoadPriorityOptimizer {
     45 public:
     46     enum VisibilityStatus {
     47         NotVisible,
     48         Visible,
     49     };
     50     void notifyImageResourceVisibility(ImageResource*, VisibilityStatus, const LayoutRect&);
     51     void updateAllImageResourcePriorities();
     52     void addRenderObject(RenderObject*);
     53     void removeRenderObject(RenderObject*);
     54 
     55     static ResourceLoadPriorityOptimizer* resourceLoadPriorityOptimizer();
     56 
     57 private:
     58     ResourceLoadPriorityOptimizer();
     59     ~ResourceLoadPriorityOptimizer();
     60 
     61     void updateImageResourcesWithLoadPriority();
     62 
     63     struct ResourceAndVisibility {
     64         ResourceAndVisibility(ImageResource*, VisibilityStatus, uint32_t);
     65         ~ResourceAndVisibility();
     66         ResourcePtr<ImageResource> imageResource;
     67         VisibilityStatus status;
     68         int screenArea;
     69     };
     70 
     71     typedef HashMap<unsigned long, OwnPtr<ResourceAndVisibility>, WTF::IntHash<unsigned>, WTF::UnsignedWithZeroKeyHashTraits<unsigned> > ImageResourceMap;
     72     ImageResourceMap m_imageResources;
     73 
     74     typedef HashSet<RenderObject*> RenderObjectSet;
     75     RenderObjectSet m_objects;
     76 };
     77 
     78 }
     79 
     80 #endif
     81