1// Copyright (c) 2011 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_SHOWN_SECTIONS_HANDLER_H_
6#define CHROME_BROWSER_UI_WEBUI_SHOWN_SECTIONS_HANDLER_H_
7#pragma once
8
9#include "chrome/browser/prefs/pref_change_registrar.h"
10#include "content/browser/webui/web_ui.h"
11#include "content/common/notification_observer.h"
12
13class Extension;
14class Value;
15class PrefService;
16
17// Use for the shown sections bitmask.
18// Currently, only the THUMB and APPS sections can be toggled by the user. Other
19// sections are shown automatically if they have data, and hidden otherwise.
20enum Section {
21  // If one of these is set, the corresponding section shows large thumbnails,
22  // else it shows only a small overview list.
23  THUMB = 1 << 0,
24  APPS = 1 << 6,
25
26  // We use the low 16 bits for sections, the high 16 bits for menu mode.
27  ALL_SECTIONS_MASK = 0x0000FFFF,
28
29  // If one of these is set, then the corresponding section is shown in a menu
30  // at the bottom of the NTP and no data is directly visible on the NTP.
31  MENU_THUMB = 1 << (0 + 16),
32  MENU_RECENT = 1 << (2 + 16),
33  MENU_APPS = 1 << (6 + 16),
34};
35
36class ShownSectionsHandler : public WebUIMessageHandler,
37                             public NotificationObserver {
38 public:
39  explicit ShownSectionsHandler(PrefService* pref_service);
40  virtual ~ShownSectionsHandler() {}
41
42  // Helper to get the current shown sections.
43  static int GetShownSections(PrefService* pref_service);
44
45  // Expands |section|, collapsing any previously expanded section. This is the
46  // same thing that happens if a user clicks on |section|.
47  static void SetShownSection(PrefService* prefs, Section section);
48
49  // WebUIMessageHandler implementation.
50  virtual void RegisterMessages();
51
52  // NotificationObserver implementation.
53  virtual void Observe(NotificationType type,
54                       const NotificationSource& source,
55                       const NotificationDetails& details);
56
57  // Callback for "getShownSections" message.
58  void HandleGetShownSections(const ListValue* args);
59
60  // Callback for "setShownSections" message.
61  void HandleSetShownSections(const ListValue* args);
62
63  static void RegisterUserPrefs(PrefService* pref_service);
64
65  static void MigrateUserPrefs(PrefService* pref_service,
66                               int old_pref_version,
67                               int new_pref_version);
68
69  static void OnExtensionInstalled(PrefService* prefs,
70                                   const Extension* extension);
71
72 private:
73  PrefService* pref_service_;
74  PrefChangeRegistrar pref_registrar_;
75
76  DISALLOW_COPY_AND_ASSIGN(ShownSectionsHandler);
77};
78
79#endif  // CHROME_BROWSER_UI_WEBUI_SHOWN_SECTIONS_HANDLER_H_
80