blob: adcf0090680e95dedd4793afe18202b7de05cbfd (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
|
// Copyright (c) 2010 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.
#ifndef CHROME_BROWSER_EXTENSIONS_IMAGE_LOADING_TRACKER_H_
#define CHROME_BROWSER_EXTENSIONS_IMAGE_LOADING_TRACKER_H_
#include "base/ref_counted.h"
#include "chrome/common/extensions/extension.h"
class ExtensionResource;
class SkBitmap;
namespace gfx {
class Size;
}
// The views need to load their icons asynchronously but might be deleted before
// the images have loaded. This class encapsulates a loader class that stays
// alive while the request is in progress (manages its own lifetime) and keeps
// track of whether the view still cares about the icon loading.
//
// To use this class, have your class derive from ImageLoadingTracker::Observer,
// and add a member variable ImageLoadingTracker tracker_. Then override
// Observer::OnImageLoaded and call:
// tracker_.LoadImage(resource, max_size);
// ... and wait for OnImageLoaded to be called back on you with a pointer to the
// SkBitmap loaded.
//
class ImageLoadingTracker {
public:
class Observer {
public:
// Will be called when the image with the given index has loaded.
// The |image| is owned by the tracker, so the observer should make a copy
// if they need to access it after this call. |image| can be null if valid
// image was not found or it failed to decode. |resource| is the
// ExtensionResource where the |image| came from and the |index| represents
// the index of the image just loaded (starts at 0 and increments every
// time this function is called).
virtual void OnImageLoaded(SkBitmap* image, ExtensionResource resource,
int index) = 0;
};
explicit ImageLoadingTracker(Observer* observer);
~ImageLoadingTracker();
// Specify image resource to load. If the loaded image is larger than
// |max_size| it will be resized to those dimensions.
void LoadImage(const ExtensionResource& resource,
gfx::Size max_size);
private:
class ImageLoader;
// When an image has finished loaded and been resized on the file thread, it
// is posted back to this method on the original thread. This method then
// calls the observer's OnImageLoaded and deletes the ImageLoadingTracker if
// it was the last image in the list.
// |image| may be null if the file failed to decode.
void OnImageLoaded(SkBitmap* image, const ExtensionResource& resource);
// The view that is waiting for the image to load.
Observer* observer_;
// The number of times we've reported back.
int responses_;
// The object responsible for loading the image on the File thread.
scoped_refptr<ImageLoader> loader_;
DISALLOW_COPY_AND_ASSIGN(ImageLoadingTracker);
};
#endif // CHROME_BROWSER_EXTENSIONS_IMAGE_LOADING_TRACKER_H_
|
