thumbnail_service.h revision 90dce4d38c5ff5333bea97d859d4e484e27edf0c 
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_THUMBNAILS_THUMBNAIL_SERVICE_H_
6#define CHROME_BROWSER_THUMBNAILS_THUMBNAIL_SERVICE_H_
7
8#include "chrome/common/thumbnail_score.h"
9#include "components/browser_context_keyed_service/refcounted_browser_context_keyed_service.h"
10#include "googleurl/src/gurl.h"
11#include "ui/gfx/image/image.h"
12
13namespace base {
14class RefCountedMemory;
15}
16
17namespace thumbnails {
18
19class ThumbnailingAlgorithm;
20struct ThumbnailingContext;
21
22// An interface abstracting access to thumbnails. Intended as a temporary
23// bridge facilitating switch from TopSites as the thumbnail source to a more
24// robust way of handling these artefacts.
25class ThumbnailService : public RefcountedBrowserContextKeyedService {
26 public:
27  // Sets the given thumbnail for the given URL. Returns true if the thumbnail
28  // was updated. False means either the URL wasn't known to us, or we felt
29  // that our current thumbnail was superior to the given one.
30  virtual bool SetPageThumbnail(const ThumbnailingContext& context,
31                                const gfx::Image& thumbnail) = 0;
32
33  // Returns the ThumbnailingAlgorithm used for processing thumbnails.
34  // It is always a new instance, the caller owns it. It will encapsulate the
35  // process of creating a thumbnail from tab contents. The lifetime of these
36  // instances is limited to the act of processing a single tab image. They
37  // are permitted to hold the state of such process.
38  virtual ThumbnailingAlgorithm* GetThumbnailingAlgorithm() const = 0;
39
40  // Gets a thumbnail for a given page. Returns true iff we have the thumbnail.
41  // This may be invoked on any thread.
42  // As this method may be invoked on any thread the ref count needs to be
43  // incremented before this method returns, so this takes a scoped_refptr*.
44  virtual bool GetPageThumbnail(
45      const GURL& url,
46      scoped_refptr<base::RefCountedMemory>* bytes) = 0;
47
48  // Returns true if the page thumbnail should be updated.
49  virtual bool ShouldAcquirePageThumbnail(const GURL& url) = 0;
50
51 protected:
52  virtual ~ThumbnailService() {}
53};
54
55}
56
57#endif  // CHROME_BROWSER_THUMBNAILS_THUMBNAIL_SERVICE_H_
58