1// Copyright (c) 2012 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 CHROME_BROWSER_EXTENSIONS_IMAGE_LOADER_H_
6#define CHROME_BROWSER_EXTENSIONS_IMAGE_LOADER_H_
7
8#include <set>
9
10#include "base/callback_forward.h"
11#include "base/gtest_prod_util.h"
12#include "base/memory/weak_ptr.h"
13#include "components/browser_context_keyed_service/browser_context_keyed_service.h"
14#include "extensions/common/extension_resource.h"
15#include "third_party/skia/include/core/SkBitmap.h"
16#include "ui/base/layout.h"
17#include "ui/gfx/size.h"
18
19class Profile;
20
21namespace gfx {
22class Image;
23}
24
25namespace extensions {
26
27class Extension;
28
29// This class is responsible for asynchronously loading extension images and
30// calling a callback when an image is loaded.
31// The views need to load their icons asynchronously might be deleted before
32// the images have loaded. If you pass your callback using a weak_ptr, this
33// will make sure the callback won't be called after the view is deleted.
34class ImageLoader : public BrowserContextKeyedService {
35 public:
36  // Information about a singe image representation to load from an extension
37  // resource.
38  struct ImageRepresentation {
39    // Enum values to indicate whether to resize loaded bitmap when it is larger
40    // than |desired_size| or always resize it.
41    enum ResizeCondition {
42      RESIZE_WHEN_LARGER,
43      ALWAYS_RESIZE,
44    };
45
46    ImageRepresentation(const ExtensionResource& resource,
47                        ResizeCondition resize_condition,
48                        const gfx::Size& desired_size,
49                        ui::ScaleFactor scale_factor);
50    ~ImageRepresentation();
51
52    // Extension resource to load.
53    ExtensionResource resource;
54
55    ResizeCondition resize_condition;
56
57    // When |resize_method| is ALWAYS_RESIZE or when the loaded image is larger
58    // than |desired_size| it will be resized to these dimensions.
59    gfx::Size desired_size;
60
61    // |scale_factor| is used to construct the loaded gfx::ImageSkia.
62    ui::ScaleFactor scale_factor;
63  };
64
65  struct LoadResult;
66
67  // Returns the instance for the given profile, or NULL if none. This is
68  // a convenience wrapper around ImageLoaderFactory::GetForProfile.
69  static ImageLoader* Get(Profile* profile);
70
71  ImageLoader();
72  virtual ~ImageLoader();
73
74  // Checks whether image is a component extension resource. Returns false
75  // if a given |resource| does not have a corresponding image in bundled
76  // resources. Otherwise fills |resource_id|. This doesn't check if the
77  // extension the resource is in is actually a component extension.
78  static bool IsComponentExtensionResource(
79      const base::FilePath& extension_path,
80      const base::FilePath& resource_path,
81      int* resource_id);
82
83  // Specify image resource to load. If the loaded image is larger than
84  // |max_size| it will be resized to those dimensions. IMPORTANT NOTE: this
85  // function may call back your callback synchronously (ie before it returns)
86  // if the image was found in the cache.
87  // Note this method loads a raw bitmap from the resource. All sizes given are
88  // assumed to be in pixels.
89  void LoadImageAsync(const extensions::Extension* extension,
90                      const ExtensionResource& resource,
91                      const gfx::Size& max_size,
92                      const base::Callback<void(const gfx::Image&)>& callback);
93
94  // Same as LoadImage() above except it loads multiple images from the same
95  // extension. This is used to load multiple resolutions of the same image
96  // type.
97  void LoadImagesAsync(const extensions::Extension* extension,
98                       const std::vector<ImageRepresentation>& info_list,
99                       const base::Callback<void(const gfx::Image&)>& callback);
100
101 private:
102  base::WeakPtrFactory<ImageLoader> weak_ptr_factory_;
103
104  static void LoadImagesOnBlockingPool(
105      const std::vector<ImageRepresentation>& info_list,
106      const std::vector<SkBitmap>& bitmaps,
107      std::vector<LoadResult>* load_result);
108
109  void ReplyBack(
110      const std::vector<LoadResult>* load_result,
111      const base::Callback<void(const gfx::Image&)>& callback);
112};
113
114}  // namespace extensions
115
116#endif  // CHROME_BROWSER_EXTENSIONS_IMAGE_LOADER_H_
117