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_CHROMEOS_TAB_CLOSEABLE_STATE_WATCHER_H_
6#define CHROME_BROWSER_CHROMEOS_TAB_CLOSEABLE_STATE_WATCHER_H_
7#pragma once
8
9#include <vector>
10
11#include "chrome/browser/tab_closeable_state_watcher.h"
12#include "chrome/browser/tabs/tab_strip_model_observer.h"
13#include "chrome/browser/ui/browser_list.h"
14#include "content/common/notification_registrar.h"
15
16namespace chromeos {
17
18// This class overrides ::TabCloseableStateWatcher to allow or disallow tabs or
19// browsers to be closed based on increase or decrease in number of tabs or
20// browsers.  We only do this on Chromeos and only for non-tests.
21//
22// Normal session:
23// 1) A tab, and hence its containing browser, is not closeable if the tab is
24// the last NewTabPage in the last normal non-incognito browser and user is not
25// signing off.
26// 2) Otherwise, if user closes a normal non-incognito browser or the last tab
27// in it, the browser stays open, the existing tabs are closed, and a new
28// NewTabPage is opened.
29// 3) Or, if user closes a normal incognito browser or the last tab in it, the
30// browser closes, a new non-incognito normal browser is opened with a
31// NewTabPage (which, by rule 1, will not be closeable).
32//
33// BWSI session (all browsers are incognito):
34// Almost the same as in the normal session, but
35// 1) A tab, and hence its containing browser, is not closeable if the tab is
36// the last NewTabPage in the last browser (again, all browsers are incognito
37// browsers).
38// 2-3) Otherwise, if user closes a normal incognito browser or the last tab in
39// it, the browser stays open, the existing tabs are closed, and a new
40// NewTabPage is open.
41
42class TabCloseableStateWatcher : public ::TabCloseableStateWatcher,
43                                 public BrowserList::Observer,
44                                 public NotificationObserver {
45 public:
46  TabCloseableStateWatcher();
47  virtual ~TabCloseableStateWatcher();
48
49  // TabCloseableStateWatcher implementation:
50  virtual bool CanCloseTab(const Browser* browser) const;
51  virtual bool CanCloseBrowser(Browser* browser);
52  virtual void OnWindowCloseCanceled(Browser* browser);
53
54 private:
55  enum BrowserActionType {
56    NONE = 0,         // Nothing to do.
57    OPEN_WINDOW = 1,  // Opens a regular (i.e. non-incognito) normal browser.
58    OPEN_NTP = 2,     // Opens a NewTabPage.
59  };
60
61  // BrowserList::Observer implementation:
62  virtual void OnBrowserAdded(const Browser* browser);
63  virtual void OnBrowserRemoved(const Browser* browser);
64
65  // NotificationObserver implementation:
66  virtual void Observe(NotificationType type, const NotificationSource& source,
67                       const NotificationDetails& details);
68
69  // Called by private class TabStripWatcher for TabStripModelObserver
70  // notifications.
71  // |closing_last_tab| is true if the tab strip is closing the last tab.
72  virtual void OnTabStripChanged(const Browser* browser, bool closing_last_tab);
73
74  // Utility functions.
75
76  // Checks the closeable state of tab.  If it has changed, updates it and
77  // notifies all normal browsers.
78  // |browser_to_check| is the browser whose closeable state the caller is
79  // interested in; can be NULL if caller is interested in all browsers, e.g.
80  // when a browser is being removed and there's no specific browser to check.
81  void CheckAndUpdateState(const Browser* browser_to_check);
82
83  // Sets the new closeable state and fires notification.
84  void SetCloseableState(bool closeable);
85
86  // Returns true if closing of |browser| is permitted.
87  // |action_type| is the action to take regardless if browser is closeable.
88  bool CanCloseBrowserImpl(const Browser* browser,
89                           BrowserActionType* action_type);
90
91  // Data members.
92
93  // This is true if tab can be closed; it's updated in CheckAndUpdateState and
94  // when sign-off notification is received.
95  bool can_close_tab_;
96
97  // This is true when sign-off notification is received; it lets us know to
98  // allow closing of all tabs and browsers in this situation.
99  bool signing_off_;
100
101  // Is in guest session?
102  bool guest_session_;
103
104  // Set to true if we're waiting for a new browser to be created. When true we
105  // uncoditionally allow everything as we know a browser is in the process of
106  // being created.
107  bool waiting_for_browser_;
108
109  NotificationRegistrar notification_registrar_;
110
111  // TabStripWatcher is a TabStripModelObserver that funnels all interesting
112  // methods to TabCloseableStateWatcher::OnTabStripChanged. TabStripWatcher is
113  // needed so we know which browser the TabStripModelObserver method relates
114  // to.
115  class TabStripWatcher : public TabStripModelObserver {
116   public:
117    TabStripWatcher(TabCloseableStateWatcher* main_watcher,
118                    const Browser* browser);
119    virtual ~TabStripWatcher();
120
121    // TabStripModelObserver implementation:
122    virtual void TabInsertedAt(TabContentsWrapper* contents, int index,
123                               bool foreground);
124    virtual void TabClosingAt(TabStripModel* tab_strip_model,
125                              TabContentsWrapper* contents,
126                              int index);
127    virtual void TabDetachedAt(TabContentsWrapper* contents, int index);
128    virtual void TabChangedAt(TabContentsWrapper* contents, int index,
129                              TabChangeType change_type);
130
131    const Browser* browser() const {
132      return browser_;
133    }
134
135   private:
136    TabCloseableStateWatcher* main_watcher_;
137    const Browser* browser_;
138
139    DISALLOW_COPY_AND_ASSIGN(TabStripWatcher);
140  };
141
142  friend class TabStripWatcher;
143
144  std::vector<TabStripWatcher*> tabstrip_watchers_;
145
146  DISALLOW_COPY_AND_ASSIGN(TabCloseableStateWatcher);
147};
148
149}  // namespace chromeos
150
151#endif  // CHROME_BROWSER_CHROMEOS_TAB_CLOSEABLE_STATE_WATCHER_H_
152