[ImageResource 4] Split ImageResource into Resource and Image parts

third_party/WebKit/Source/core/fetch/ImageResourceContent.h

-/*
-    Copyright (C) 1998 Lars Knoll (knoll@mpi-hd.mpg.de)
-    Copyright (C) 2001 Dirk Mueller <mueller@kde.org>
-    Copyright (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
-    Copyright (C) 2004, 2005, 2006, 2007 Apple Inc. All rights reserved.
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
 
-    This library is free software; you can redistribute it and/or
-    modify it under the terms of the GNU Library General Public
-    License as published by the Free Software Foundation; either
-    version 2 of the License, or (at your option) any later version.
-
-    This library is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-    Library General Public License for more details.
-
-    You should have received a copy of the GNU Library General Public License
-    along with this library; see the file COPYING.LIB.  If not, write to
-    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
-    Boston, MA 02110-1301, USA.
-*/
-
-#ifndef ImageResource_h
-#define ImageResource_h
+#ifndef ImageResourceContent_h
+#define ImageResourceContent_h
 
 #include "core/CoreExport.h"
-#include "core/fetch/MultipartImageResourceParser.h"
-#include "core/fetch/Resource.h"
+#include "core/fetch/ResourceStatus.h"
 #include "platform/geometry/IntRect.h"
 #include "platform/geometry/IntSizeHash.h"
 #include "platform/geometry/LayoutSize.h"
 #include "platform/graphics/Image.h"
 #include "platform/graphics/ImageObserver.h"
 #include "platform/graphics/ImageOrientation.h"
+#include "platform/network/ResourceLoadPriority.h"
+#include "platform/weborigin/KURL.h"
+#include "wtf/HashCountedSet.h"
 #include "wtf/HashMap.h"
 #include <memory>
 
 namespace blink {
 
 class FetchRequest;
+class ImageResourceInfo;
 class ImageResourceObserver;
-class MemoryCache;
-class ResourceClient;
+class ResourceError;
 class ResourceFetcher;
+class ResourceResponse;
 class SecurityOrigin;
 
-// ImageResource class represents an image type resource.
-//
-// As for the lifetimes of m_image and m_data, see this document:
-// https://docs.google.com/document/d/1v0yTAZ6wkqX2U_M6BNIGUJpM1s0TIw1VsqpxoL7aciY/edit?usp=sharing
-class CORE_EXPORT ImageResource final
-    : public Resource,
-      public ImageObserver,
-      public MultipartImageResourceParser::Client {
-  friend class MemoryCache;
-  USING_GARBAGE_COLLECTED_MIXIN(ImageResource);
+// ImageResourceContent is a container that holds fetch result of
+// an ImageResource in a decoded form.
+// Classes that use the fetched images
+// should hold onto this class and/or inherit ImageResourceObserver,
+// instead of holding onto ImageResource or inheriting ResourceClient.
+// https://docs.google.com/document/d/1O-fB83mrE0B_V8gzXNqHgmRLCvstTB4MMi3RnVLr8bE/edit?usp=sharing
+// TODO(hiroshige): Make ImageResourceContent ResourceClient and remove the
+// word 'observer' from ImageResource.
+// TODO(hiroshige): Rename local variables of type ImageResourceContent to
+// e.g. |imageContent|. Currently they have Resource-like names.
+class CORE_EXPORT ImageResourceContent final
+    : public GarbageCollectedFinalized<ImageResourceContent>,
+      public ImageObserver {
+  USING_GARBAGE_COLLECTED_MIXIN(ImageResourceContent);
 
  public:
-  using ClientType = ResourceClient;
+  static ImageResourceContent* create(
+      PassRefPtr<blink::Image> image = nullptr) {
+    return new ImageResourceContent(std::move(image));
+  }
+  static ImageResourceContent* fetch(FetchRequest&, ResourceFetcher*);
 
-  static ImageResource* fetch(FetchRequest&, ResourceFetcher*);
-
-  static ImageResource* create(blink::Image* image) {
-    return new ImageResource(image, ResourceLoaderOptions());
-  }
-
-  static ImageResource* create(const ResourceRequest& request) {
-    return new ImageResource(request, ResourceLoaderOptions(), false);
-  }
-
-  ~ImageResource() override;
-
-  blink::Image*
-  getImage();  // Returns the nullImage() if the image is not available yet.
+  // Returns the nullImage() if the image is not available yet.
+  blink::Image* getImage() const;

[kinuko, 2016/12/09 10:42:24]

ditto, avoid returning non-const ptr from const method

[hiroshige, 2016/12/11 19:17:02]

I found ImageResource already have potentials for this kind of const
inconsistency.
For example, in ImageResource::resourceBuffer() const,
|m_image->data()| is called, where data() is non-const method.
Replacing |m_image| with getImage() made this inconsistency explicit.

BTW, I also found that I shouldn't have replaced |m_image| with |getImage()|,
because ImageResourceContent::getImage() is NOT a simple getter of |m_image|.
Two callsites of getImage() are affected (ImageResource::resourceBuffer() and
ImageResource::appendData()).

In PatchSet 35,
- I made getImage() non-const method.
- I moved the blocks containing the affected getImage() callsites to
ImageResourceContent, and reverted them back to |m_image|.
- I made ImageResourceContent::isAccessAllowed() non-const, because it calls
getImage(). (ImageResource::isAccessAllowed() was non-const before this CL)

This doesn't make things worse, just makes the problem implicit again though.

   bool hasImage() const { return m_image.get(); }
 
   static std::pair<blink::Image*, float> brokenImage(
       float deviceScaleFactor);  // Returns an image and the image's resolution
                                  // scale factor.
-  bool willPaintBrokenImage() const;
 
   bool usesImageContainerSize() const;
   bool imageHasRelativeSize() const;
   // The device pixel ratio we got from the server for this image, or 1.0.
-  float devicePixelRatioHeaderValue() const {
-    return m_devicePixelRatioHeaderValue;
-  }
-  bool hasDevicePixelRatioHeaderValue() const {
-    return m_hasDevicePixelRatioHeaderValue;
-  }
+  float devicePixelRatioHeaderValue() const;
+  bool hasDevicePixelRatioHeaderValue() const;
 
   enum SizeType {
     // Report the intrinsic size.
     IntrinsicSize,
 
     // Report the intrinsic size corrected to account for image density.
     IntrinsicCorrectedToDPR,
   };
 
   // This method takes a zoom multiplier that can be used to increase the
   // natural size of the image by the zoom.
   LayoutSize imageSize(
       RespectImageOrientationEnum shouldRespectImageOrientation,
       float multiplier,
       SizeType = IntrinsicSize);
 
-  bool isAccessAllowed(SecurityOrigin*);
-
   void updateImageAnimationPolicy();
 
-  enum class ReloadCachePolicy {
-    UseExistingPolicy = 0,  // Don't modify the request's cache policy.
-    BypassCache,  // Modify the request so that the reload bypasses the cache.
-  };
-
-  // If this ImageResource has the Lo-Fi response headers or is a placeholder,
-  // reload the full original image with the Lo-Fi state set to off and
-  // optionally bypassing the cache.
-  void reloadIfLoFiOrPlaceholder(
-      ResourceFetcher*,
-      ReloadCachePolicy = ReloadCachePolicy::BypassCache);
-
-  void didAddClient(ResourceClient*) override;
-
   void addObserver(ImageResourceObserver*);
   void removeObserver(ImageResourceObserver*);
 
-  ResourcePriority priorityFromObservers() override;
+  DECLARE_TRACE();
 
-  void allClientsAndObserversRemoved() override;
+  // Redirecting methods to Resource.
+  const KURL& url() const;
+  bool isAccessAllowed(SecurityOrigin*) const;
+  const ResourceResponse& response() const;
+  bool isLoaded() const;
+  bool isLoading() const;
+  bool errorOccurred() const;
+  bool loadFailedOrCanceled() const;
+  ResourceStatus getStatus() const;
+  const ResourceError& resourceError() const;
 
-  PassRefPtr<const SharedBuffer> resourceBuffer() const override;
-  void appendData(const char*, size_t) override;
-  void error(const ResourceError&) override;
-  void responseReceived(const ResourceResponse&,
-                        std::unique_ptr<WebDataConsumerHandle>) override;
-  void finish(double finishTime = 0.0) override;
+  // For FrameSerializer.
+  bool hasCacheControlNoStoreHeader() const;
 
-  // For compatibility, images keep loading even if there are HTTP errors.
-  bool shouldIgnoreHTTPStatusCodeErrors() const override { return true; }
-
-  bool isImage() const override { return true; }
-
-  // ImageObserver
-  void decodedSizeChangedTo(const blink::Image*, size_t newSize) override;
-
-  bool shouldPauseAnimation(const blink::Image*) override;
-  void animationAdvanced(const blink::Image*) override;
-  void changedInRect(const blink::Image*, const IntRect&) override;
-
-  // MultipartImageResourceParser::Client
-  void onePartInMultipartReceived(const ResourceResponse&) final;
-  void multipartDataReceived(const char*, size_t) final;
-
-  // Used by tests.
-  bool isPlaceholder() const { return m_isPlaceholder; }
-
-  bool shouldReloadBrokenPlaceholder() const {
-    return m_isPlaceholder && willPaintBrokenImage();
-  }
+  void emulateLoadStartedForInspector(ResourceFetcher*,
+                                      const KURL&,
+                                      const AtomicString& initiatorName);
 
   void setNotRefetchableDataFromDiskCache() {
     m_isRefetchableDataFromDiskCache = false;
   }
 
-  DECLARE_VIRTUAL_TRACE();
+  // For ImageResource only.
+  void setImageResourceInfo(ImageResourceInfo*);
+  enum ClearImageOption { ClearExistingImage, KeepExistingImage };
+  void updateImage(PassRefPtr<SharedBuffer>,
+                   ClearImageOption,
+                   bool allDataReceived);
+  enum NotifyFinishOption { ShouldNotifyFinish, DoNotNotifyFinish };
+  void clearImage();
+  void clearImageAndNotifyObservers(NotifyFinishOption);
+  ResourcePriority priorityFromObservers() const;
+  void destroyDecodedData();
+  bool hasObservers() const {
+    return !m_observers.isEmpty() || !m_finishedObservers.isEmpty();
+  }
+  bool isSizeAvailable() const {
+    return m_sizeAvailable == Image::SizeAvailable;
+  }
+  bool isRefetchableDataFromDiskCache() const {
+    return m_isRefetchableDataFromDiskCache;
+  }
+  void doResetAnimation();
 
  private:
-  explicit ImageResource(blink::Image*, const ResourceLoaderOptions&);
+  ImageResourceContent(PassRefPtr<blink::Image> = nullptr);

[kinuko, 2016/12/09 10:42:24]

explicit

[hiroshige, 2016/12/11 19:17:02]

Done.

 
-  enum class MultipartParsingState : uint8_t {
-    WaitingForFirstPart,
-    ParsingFirstPart,
-    FinishedParsingFirstPart,
-  };
+  // ImageObserver
+  void decodedSizeChangedTo(const blink::Image*, size_t newSize) override;
+  bool shouldPauseAnimation(const blink::Image*) override;
+  void animationAdvanced(const blink::Image*) override;
+  void changedInRect(const blink::Image*, const IntRect&) override;
 
-  class ImageResourceFactory;
+  PassRefPtr<Image> createImage();
 
-  ImageResource(const ResourceRequest&,
-                const ResourceLoaderOptions&,
-                bool isPlaceholder);
-
-  bool hasClientsOrObservers() const override {
-    return Resource::hasClientsOrObservers() || !m_observers.isEmpty() ||
-           !m_finishedObservers.isEmpty();
-  }
-  void clear();
-
-  void createImage();
-  void updateImage(bool allDataReceived);
-  void updateImageAndClearBuffer();
-  void clearImage();
-  enum NotifyFinishOption { ShouldNotifyFinish, DoNotNotifyFinish };
   // If not null, changeRect is the changed part of the image.
   void notifyObservers(NotifyFinishOption, const IntRect* changeRect = nullptr);
-
-  void ensureImage();
-
-  void checkNotify() override;
-  void notifyObserversInternal();
   void markObserverFinished(ImageResourceObserver*);
 
-  void doResetAnimation();
+  Member<ImageResourceInfo> m_info;
 
-  void destroyDecodedDataIfPossible() override;
-  void destroyDecodedDataForFailedRevalidation() override;
+  RefPtr<blink::Image> m_image;
 
-  void flushImageIfNeeded(TimerBase*);
-
-  float m_devicePixelRatioHeaderValue;
-
-  Member<MultipartImageResourceParser> m_multipartParser;
-  RefPtr<blink::Image> m_image;
-  MultipartParsingState m_multipartParsingState =
-      MultipartParsingState::WaitingForFirstPart;
-  bool m_hasDevicePixelRatioHeaderValue;
   HashCountedSet<ImageResourceObserver*> m_observers;
   HashCountedSet<ImageResourceObserver*> m_finishedObservers;
 
-  // Indicates if the ImageResource is currently scheduling a reload, e.g.
-  // because reloadIfLoFi() was called.
-  bool m_isSchedulingReload;
-
-  // Indicates if this ImageResource is either attempting to load a placeholder
-  // image, or is a (possibly broken) placeholder image.
-  bool m_isPlaceholder;
-
-  Timer<ImageResource> m_flushTimer;
-  double m_lastFlushTime = 0.;
   Image::SizeAvailability m_sizeAvailable = Image::SizeUnavailable;
 
   // Indicates if this resource's encoded image data can be purged and refetched
   // from disk cache to save memory usage. See crbug/664437.
   bool m_isRefetchableDataFromDiskCache;
 };
 
-DEFINE_RESOURCE_TYPE_CASTS(Image);
-
 }  // namespace blink
 
 #endif