chrome/browser/sessions/session_restore.h

   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_SESSIONS_SESSION_RESTORE_H_
   6 #define CHROME_BROWSER_SESSIONS_SESSION_RESTORE_H_
   7
   8 #include <vector>
   9
  10 #include "base/basictypes.h"
  11 #include "base/callback_list.h"
  12 #include "chrome/browser/history/history_service.h"
  13 #include "chrome/browser/ui/host_desktop.h"
  14 #include "components/sessions/session_types.h"
  15 #include "ui/base/window_open_disposition.h"
  16
  17 class Browser;
  18 class Profile;
  19
  20 namespace content {
  21 class WebContents;
  22 }
  23
  24 // SessionRestore handles restoring either the last or saved session. Session
  25 // restore come in two variants, asynchronous or synchronous. The synchronous
  26 // variety is meant for startup and blocks until restore is complete.
  27 class SessionRestore {
  28  public:
  29   enum Behavior {
  30     // Indicates the active tab of the supplied browser should be closed.
  31     CLOBBER_CURRENT_TAB          = 1 << 0,
  32
  33     // Indicates that if there is a problem restoring the last session then a
  34     // new tabbed browser should be created.
  35     ALWAYS_CREATE_TABBED_BROWSER = 1 << 1,
  36
  37     // Restore blocks until complete. This is intended for use during startup
  38     // when we want to block until restore is complete.
  39     SYNCHRONOUS                  = 1 << 2,
  40   };
  41
  42   // Notification callback list.
  43   using CallbackList = base::CallbackList<void(int)>;
  44
  45   // Used by objects calling RegisterOnSessionRestoredCallback() to de-register
  46   // themselves when they are destroyed.
  47   using CallbackSubscription =
  48       scoped_ptr<base::CallbackList<void(int)>::Subscription>;
  49
  50   // Restores the last session. |behavior| is a bitmask of Behaviors, see it
  51   // for details. If |browser| is non-null the tabs for the first window are
  52   // added to it. Returns the last active browser.
  53   // Every additional browser created will be created on the desktop specified
  54   // by |host_desktop_type|, if |browser| is non-null it should have the same
  55   // desktop type.
  56   //
  57   // If |urls_to_open| is non-empty, a tab is added for each of the URLs.
  58   static Browser* RestoreSession(Profile* profile,
  59                                  Browser* browser,
  60                                  chrome::HostDesktopType host_desktop_type,
  61                                  uint32 behavior,
  62                                  const std::vector<GURL>& urls_to_open);
  63
  64   // Restores the last session when the last session crashed. It's a wrapper
  65   // of function RestoreSession.
  66   static void RestoreSessionAfterCrash(Browser* browser);
  67
  68   // Specifically used in the restoration of a foreign session.  This function
  69   // restores the given session windows to multiple browsers all of which
  70   // will be created on the desktop specified by |host_desktop_type|. Returns
  71   // the created Browsers.
  72   static std::vector<Browser*> RestoreForeignSessionWindows(
  73       Profile* profile,
  74       chrome::HostDesktopType host_desktop_type,
  75       std::vector<const sessions::SessionWindow*>::const_iterator begin,
  76       std::vector<const sessions::SessionWindow*>::const_iterator end);
  77
  78   // Specifically used in the restoration of a foreign session.  This method
  79   // restores the given session tab to the browser of |source_web_contents| if
  80   // the disposition is not NEW_WINDOW. Returns the WebContents corresponding
  81   // to the restored tab. If |disposition| is CURRENT_TAB, |source_web_contents|
  82   // may be destroyed.
  83   static content::WebContents* RestoreForeignSessionTab(
  84       content::WebContents* source_web_contents,
  85       const sessions::SessionTab& tab,
  86       WindowOpenDisposition disposition);
  87
  88   // Returns true if we're in the process of restoring |profile|.
  89   static bool IsRestoring(const Profile* profile);
  90
  91   // Returns true if synchronously restoring a session.
  92   static bool IsRestoringSynchronously();
  93
  94   // Register callbacks for session restore events. These callbacks are stored
  95   // in |on_session_restored_callbacks_|.
  96   // The callback is supplied an integer arg representing a tab count. The exact
  97   // meaning and timing depend upon the restore type:
  98   // - SessionRestore::SYNCHRONOUS: the parameter is the number of tabs that
  99   // were created. Additionally the callback is invoked immediately after the
 100   // tabs have been created. That is, the tabs are not necessarily loading.
 101   // - For all other restore types the parameter is the number of tabs that were
 102   // restored and is sent after all tabs have started loading. Additionally if a
 103   // request to restore tabs comes in while a previous request to restore tabs
 104   // has not yet completed (loading tabs is throttled), then the callback is
 105   // only notified once both sets of tabs have started loading and with the
 106   // total number of tabs for both restores.
 107   static CallbackSubscription RegisterOnSessionRestoredCallback(
 108       const base::Callback<void(int)>& callback);
 109
 110   // The max number of non-selected tabs SessionRestore loads when restoring
 111   // a session. A value of 0 indicates all tabs are loaded at once.
 112   static size_t num_tabs_to_load_;
 113
 114  private:
 115   SessionRestore();
 116
 117   // Accessor for |*on_session_restored_callbacks_|. Creates a new object the
 118   // first time so that it always returns a valid object.
 119   static CallbackList* on_session_restored_callbacks() {
 120     if (!on_session_restored_callbacks_)
 121       on_session_restored_callbacks_ = new CallbackList();
 122     return on_session_restored_callbacks_;
 123   }
 124
 125   // Contains all registered callbacks for session restore notifications.
 126   static CallbackList* on_session_restored_callbacks_;
 127
 128   DISALLOW_COPY_AND_ASSIGN(SessionRestore);
 129 };
 130
 131 #endif  // CHROME_BROWSER_SESSIONS_SESSION_RESTORE_H_