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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, 2009 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 
     23 #ifndef ImageLoader_h
     24 #define ImageLoader_h
     25 
     26 #include "core/loader/cache/ImageResource.h"
     27 #include "core/loader/cache/ImageResourceClient.h"
     28 #include "core/loader/cache/ResourcePtr.h"
     29 #include "wtf/HashSet.h"
     30 #include "wtf/text/AtomicString.h"
     31 
     32 namespace WebCore {
     33 
     34 class ImageLoaderClient {
     35 public:
     36     virtual void notifyImageSourceChanged() = 0;
     37 
     38     // Determines whether the observed ImageResource should have higher priority in the decoded resources cache.
     39     virtual bool requestsHighLiveResourceCachePriority() { return false; }
     40 
     41 protected:
     42     ImageLoaderClient() { }
     43 };
     44 
     45 class Element;
     46 class ImageLoader;
     47 class RenderImageResource;
     48 
     49 template<typename T> class EventSender;
     50 typedef EventSender<ImageLoader> ImageEventSender;
     51 
     52 class ImageLoader : public ImageResourceClient {
     53 public:
     54     explicit ImageLoader(Element*);
     55     virtual ~ImageLoader();
     56 
     57     // This function should be called when the element is attached to a document; starts
     58     // loading if a load hasn't already been started.
     59     void updateFromElement();
     60 
     61     // This function should be called whenever the 'src' attribute is set, even if its value
     62     // doesn't change; starts new load unconditionally (matches Firefox and Opera behavior).
     63     void updateFromElementIgnoringPreviousError();
     64 
     65     void elementDidMoveToNewDocument();
     66 
     67     Element* element() const { return m_element; }
     68     bool imageComplete() const { return m_imageComplete; }
     69 
     70     ImageResource* image() const { return m_image.get(); }
     71     void setImage(ImageResource*); // Cancels pending beforeload and load events, and doesn't dispatch new ones.
     72 
     73     void setLoadManually(bool loadManually) { m_loadManually = loadManually; }
     74 
     75     bool hasPendingBeforeLoadEvent() const { return m_hasPendingBeforeLoadEvent; }
     76     bool hasPendingActivity() const { return m_hasPendingLoadEvent || m_hasPendingErrorEvent; }
     77 
     78     void dispatchPendingEvent(ImageEventSender*);
     79 
     80     static void dispatchPendingBeforeLoadEvents();
     81     static void dispatchPendingLoadEvents();
     82     static void dispatchPendingErrorEvents();
     83 
     84     void addClient(ImageLoaderClient*);
     85     void removeClient(ImageLoaderClient*);
     86 
     87 protected:
     88     virtual void notifyFinished(Resource*);
     89 
     90 private:
     91     virtual void dispatchLoadEvent() = 0;
     92     virtual String sourceURI(const AtomicString&) const = 0;
     93 
     94     void updatedHasPendingEvent();
     95 
     96     void dispatchPendingBeforeLoadEvent();
     97     void dispatchPendingLoadEvent();
     98     void dispatchPendingErrorEvent();
     99 
    100     RenderImageResource* renderImageResource();
    101     void updateRenderer();
    102 
    103     void setImageWithoutConsideringPendingLoadEvent(ImageResource*);
    104     void sourceImageChanged();
    105     void clearFailedLoadURL();
    106 
    107     void timerFired(Timer<ImageLoader>*);
    108 
    109     Element* m_element;
    110     ResourcePtr<ImageResource> m_image;
    111     HashSet<ImageLoaderClient*> m_clients;
    112     Timer<ImageLoader> m_derefElementTimer;
    113     AtomicString m_failedLoadURL;
    114     bool m_hasPendingBeforeLoadEvent : 1;
    115     bool m_hasPendingLoadEvent : 1;
    116     bool m_hasPendingErrorEvent : 1;
    117     bool m_imageComplete : 1;
    118     bool m_loadManually : 1;
    119     bool m_elementIsProtected : 1;
    120     unsigned m_highPriorityClientCount;
    121 };
    122 
    123 }
    124 
    125 #endif
    126