thumbnail_source.h revision 2a99a7e74a7f215066514fe81d2bfa6639d9eddd 
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_UI_WEBUI_NTP_THUMBNAIL_SOURCE_H_
6#define CHROME_BROWSER_UI_WEBUI_NTP_THUMBNAIL_SOURCE_H_
7
8#include <map>
9#include <string>
10
11#include "base/basictypes.h"
12#include "base/memory/ref_counted.h"
13#include "content/public/browser/url_data_source.h"
14
15class Profile;
16
17namespace base {
18class RefCountedMemory;
19}
20
21namespace thumbnails {
22class ThumbnailService;
23}
24
25// ThumbnailSource is the gateway between network-level chrome: requests for
26// thumbnails and the history/top-sites backend that serves these.
27class ThumbnailSource : public content::URLDataSource {
28 public:
29  explicit ThumbnailSource(Profile* profile);
30
31  // content::URLDataSource implementation.
32  virtual std::string GetSource() OVERRIDE;
33  virtual void StartDataRequest(
34      const std::string& path,
35      bool is_incognito,
36      const content::URLDataSource::GotDataCallback& callback) OVERRIDE;
37  virtual std::string GetMimeType(const std::string& path) const OVERRIDE;
38  virtual MessageLoop* MessageLoopForRequestPath(
39      const std::string& path) const OVERRIDE;
40  virtual bool ShouldServiceRequest(
41      const net::URLRequest* request) const OVERRIDE;
42
43 private:
44  virtual ~ThumbnailSource();
45
46  // Raw PNG representation of the thumbnail to show when the thumbnail
47  // database doesn't have a thumbnail for a webpage.
48  scoped_refptr<base::RefCountedMemory> default_thumbnail_;
49
50  // ThumbnailService.
51  scoped_refptr<thumbnails::ThumbnailService> thumbnail_service_;
52
53  // Transient mappings from an ID-based path to an URL-based path.
54  // The key is an ID-string, the value is a URL string.
55  // Mappings are added in ShouldServiceRequest() and erased once
56  // the request is serviced in StartDataRequest().
57  // TODO(dhollowa): Consider passing the |request| object through
58  // to the StartDataRequest() call.
59  mutable std::map<std::string, std::string> id_to_url_map_;
60
61  // Only used when servicing requests on the UI thread.
62  Profile* const profile_;
63
64  DISALLOW_COPY_AND_ASSIGN(ThumbnailSource);
65};
66
67#endif  // CHROME_BROWSER_UI_WEBUI_NTP_THUMBNAIL_SOURCE_H_
68