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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/fetch/ImageResource.h"
     27 #include "core/fetch/ImageResourceClient.h"
     28 #include "core/fetch/ResourcePtr.h"
     29 #include "platform/heap/Handle.h"
     30 #include "wtf/HashSet.h"
     31 #include "wtf/WeakPtr.h"
     32 #include "wtf/text/AtomicString.h"
     33 
     34 namespace blink {
     35 
     36 class IncrementLoadEventDelayCount;
     37 class FetchRequest;
     38 class Document;
     39 
     40 class ImageLoaderClient : public WillBeGarbageCollectedMixin {
     41 public:
     42     virtual void notifyImageSourceChanged() = 0;
     43 
     44     // Determines whether the observed ImageResource should have higher priority in the decoded resources cache.
     45     virtual bool requestsHighLiveResourceCachePriority() { return false; }
     46 
     47     virtual void trace(Visitor*) { }
     48 
     49 protected:
     50     ImageLoaderClient() { }
     51 };
     52 
     53 class Element;
     54 class ImageLoader;
     55 class RenderImageResource;
     56 
     57 template<typename T> class EventSender;
     58 typedef EventSender<ImageLoader> ImageEventSender;
     59 
     60 class ImageLoader : public NoBaseWillBeGarbageCollectedFinalized<ImageLoader>, public ImageResourceClient {
     61 public:
     62     explicit ImageLoader(Element*);
     63     virtual ~ImageLoader();
     64     void trace(Visitor*);
     65 
     66     enum LoadType {
     67         LoadNormally,
     68         ForceLoadImmediately
     69     };
     70 
     71     enum UpdateFromElementBehavior {
     72         // This should be the update behavior when the element is attached to a document, or when DOM mutations trigger a new load.
     73         // Starts loading if a load hasn't already been started.
     74         UpdateNormal,
     75         // This should be the update behavior when the resource was changed (via 'src', 'srcset' or 'sizes').
     76         // Starts a new load even if a previous load of the same resource have failed, to match Firefox's behavior.
     77         // FIXME - Verify that this is the right behavior according to the spec.
     78         UpdateIgnorePreviousError,
     79         // This forces the image to update its intrinsic size, even if the image source has not changed.
     80         UpdateSizeChanged
     81     };
     82 
     83     enum BypassMainWorldBehavior {
     84         BypassMainWorldCSP,
     85         DoNotBypassMainWorldCSP
     86     };
     87 
     88     void updateFromElement(UpdateFromElementBehavior = UpdateNormal, LoadType = LoadNormally);
     89 
     90     void elementDidMoveToNewDocument();
     91 
     92     Element* element() const { return m_element; }
     93     bool imageComplete() const
     94     {
     95         return m_imageComplete && !m_pendingTask;
     96     }
     97 
     98     ImageResource* image() const { return m_image.get(); }
     99     void setImage(ImageResource*); // Cancels pending load events, and doesn't dispatch new ones.
    100 
    101     void setLoadingImageDocument() { m_loadingImageDocument = true; }
    102 
    103     bool hasPendingActivity() const
    104     {
    105         return m_hasPendingLoadEvent || m_hasPendingErrorEvent || m_pendingTask;
    106     }
    107 
    108     void dispatchPendingEvent(ImageEventSender*);
    109 
    110     static void dispatchPendingLoadEvents();
    111     static void dispatchPendingErrorEvents();
    112 
    113     void addClient(ImageLoaderClient*);
    114     void removeClient(ImageLoaderClient*);
    115 
    116 protected:
    117     virtual void notifyFinished(Resource*) OVERRIDE;
    118 
    119 private:
    120     class Task;
    121 
    122     // Called from the task or from updateFromElement to initiate the load.
    123     void doUpdateFromElement(BypassMainWorldBehavior, UpdateFromElementBehavior);
    124 
    125     virtual void dispatchLoadEvent() = 0;
    126     virtual String sourceURI(const AtomicString&) const = 0;
    127 
    128     void updatedHasPendingEvent();
    129 
    130     void dispatchPendingLoadEvent();
    131     void dispatchPendingErrorEvent();
    132 
    133     RenderImageResource* renderImageResource();
    134     void updateRenderer();
    135 
    136     void setImageWithoutConsideringPendingLoadEvent(ImageResource*);
    137     void sourceImageChanged();
    138     void clearFailedLoadURL();
    139     void crossSiteOrCSPViolationOccured(AtomicString);
    140     void enqueueImageLoadingMicroTask(UpdateFromElementBehavior);
    141     static ResourcePtr<ImageResource> createImageResourceForImageDocument(Document&, FetchRequest&);
    142 
    143     void timerFired(Timer<ImageLoader>*);
    144 
    145     KURL imageSourceToKURL(AtomicString) const;
    146 
    147     // Used to determine whether to immediately initiate the load
    148     // or to schedule a microtask.
    149     bool shouldLoadImmediately(const KURL&, LoadType) const;
    150 
    151     void willRemoveClient(ImageLoaderClient&);
    152 
    153     RawPtrWillBeMember<Element> m_element;
    154     ResourcePtr<ImageResource> m_image;
    155     // FIXME: Oilpan: We might be able to remove this Persistent hack when
    156     // ImageResourceClient is traceable.
    157     GC_PLUGIN_IGNORE("http://crbug.com/383741")
    158     RefPtrWillBePersistent<Element> m_keepAlive;
    159 #if ENABLE(OILPAN)
    160     class ImageLoaderClientRemover {
    161     public:
    162         ImageLoaderClientRemover(ImageLoader& loader, ImageLoaderClient& client) : m_loader(loader), m_client(client) { }
    163         ~ImageLoaderClientRemover();
    164 
    165     private:
    166         ImageLoader& m_loader;
    167         ImageLoaderClient& m_client;
    168     };
    169     friend class ImageLoaderClientRemover;
    170     // Oilpan: This ImageLoader object must outlive its clients because they
    171     // need to call ImageLoader::willRemoveClient before they
    172     // die. Non-Persistent HeapHashMap doesn't work well because weak processing
    173     // for HeapHashMap is not triggered when both of ImageLoader and
    174     // ImageLoaderClient are unreachable.
    175     GC_PLUGIN_IGNORE("http://crbug.com/383742")
    176     PersistentHeapHashMap<WeakMember<ImageLoaderClient>, OwnPtr<ImageLoaderClientRemover> > m_clients;
    177 #else
    178     HashSet<ImageLoaderClient*> m_clients;
    179 #endif
    180     Timer<ImageLoader> m_derefElementTimer;
    181     AtomicString m_failedLoadURL;
    182     WeakPtr<Task> m_pendingTask; // owned by Microtask
    183     OwnPtr<IncrementLoadEventDelayCount> m_loadDelayCounter;
    184     bool m_hasPendingLoadEvent : 1;
    185     bool m_hasPendingErrorEvent : 1;
    186     bool m_imageComplete : 1;
    187     bool m_loadingImageDocument : 1;
    188     bool m_elementIsProtected : 1;
    189     unsigned m_highPriorityClientCount;
    190 };
    191 
    192 }
    193 
    194 #endif
    195