content/renderer/image_loading_helper.h

   1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CONTENT_RENDERER_IMAGE_LOADING_HELPER_H_
   6 #define CONTENT_RENDERER_IMAGE_LOADING_HELPER_H_
   7
   8 #include <string>
   9 #include <vector>
  10
  11 #include "base/memory/scoped_vector.h"
  12 #include "content/public/renderer/render_view_observer.h"
  13 #include "googleurl/src/gurl.h"
  14
  15 class SkBitmap;
  16
  17 namespace webkit_glue {
  18 class MultiResolutionImageResourceFetcher;
  19 }
  20
  21 namespace content {
  22
  23 // This class deals with image downloading.
  24 // One instance of ImageLoadingHelper is owned by RenderView.
  25 class ImageLoadingHelper : public RenderViewObserver {
  26  public:
  27   explicit ImageLoadingHelper(RenderView* render_view);
  28
  29  private:
  30   virtual ~ImageLoadingHelper();
  31
  32   // Message handler.
  33   void OnDownloadImage(int id,
  34                        const GURL& image_url,
  35                        bool is_favicon,
  36                        int image_size);
  37
  38   // Requests to download an image. When done, the ImageLoadingHelper
  39   // is notified by way of DidDownloadImage. Returns true if the
  40   // request was successfully started, false otherwise. id is used to
  41   // uniquely identify the request and passed back to the
  42   // DidDownloadImage method. If the image is a favicon, cookies will not be
  43   // sent nor accepted during download. If the image has multiple frames, the
  44   // frame whose size is image_size is returned. If the image doesn't
  45   // have a frame at the specified size, the first is returned.
  46   bool DownloadImage(int id,
  47                      const GURL& image_url,
  48                      bool is_favicon,
  49                      int image_size);
  50
  51   // This callback is triggered when DownloadImage completes, either
  52   // succesfully or with a failure. See DownloadImage for more
  53   // details.
  54   void DidDownloadImage(
  55       int requested_size,
  56       webkit_glue::MultiResolutionImageResourceFetcher* fetcher,
  57       const std::vector<SkBitmap>& images);
  58
  59   // Decodes a data: URL image or returns an empty image in case of failure.
  60   SkBitmap ImageFromDataUrl(const GURL&) const;
  61
  62   // RenderViewObserver implementation.
  63   virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
  64
  65   typedef ScopedVector<webkit_glue::MultiResolutionImageResourceFetcher>
  66       ImageResourceFetcherList;
  67
  68   // ImageResourceFetchers schedule via DownloadImage.
  69   ImageResourceFetcherList image_fetchers_;
  70
  71   DISALLOW_COPY_AND_ASSIGN(ImageLoadingHelper);
  72 };
  73
  74 }  // namespace content
  75
  76 #endif  // CONTENT_RENDERER_IMAGE_LOADING_HELPER_H_
  77