chrome/browser/ui/browser_tab_restorer.cc

   1 // Copyright 2014 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 #include "base/metrics/user_metrics_action.h"
   6 #include "base/supports_user_data.h"
   7 #include "chrome/browser/profiles/profile.h"
   8 #include "chrome/browser/sessions/tab_restore_service_factory.h"
   9 #include "chrome/browser/ui/browser.h"
  10 #include "chrome/browser/ui/browser_commands.h"
  11 #include "chrome/browser/ui/browser_list.h"
  12 #include "chrome/browser/ui/browser_list_observer.h"
  13 #include "chrome/browser/ui/browser_tab_restore_service_delegate.h"
  14 #include "components/sessions/core/tab_restore_service.h"
  15 #include "components/sessions/core/tab_restore_service_observer.h"
  16 #include "content/public/browser/user_metrics.h"
  17
  18 namespace chrome {
  19 namespace {
  20
  21 const char kBrowserTabRestorerKey[] = "BrowserTabRestorer";
  22
  23 // BrowserTabRestorer is responsible for restoring a tab when the
  24 // sessions::TabRestoreService finishes loading. A TabRestoreService is
  25 // associated with a
  26 // single Browser and deletes itself if the Browser is destroyed.
  27 // BrowserTabRestorer is installed on the Profile (by way of user data), only
  28 // one instance is created per profile at a time.
  29 class BrowserTabRestorer : public sessions::TabRestoreServiceObserver,
  30                            public chrome::BrowserListObserver,
  31                            public base::SupportsUserData::Data {
  32  public:
  33   ~BrowserTabRestorer() override;
  34
  35   static void CreateIfNecessary(Browser* browser);
  36
  37  private:
  38   explicit BrowserTabRestorer(Browser* browser);
  39
  40   // TabRestoreServiceObserver:
  41   void TabRestoreServiceChanged(sessions::TabRestoreService* service) override;
  42   void TabRestoreServiceDestroyed(
  43       sessions::TabRestoreService* service) override;
  44   void TabRestoreServiceLoaded(sessions::TabRestoreService* service) override;
  45
  46   // BrowserListObserver:
  47   void OnBrowserRemoved(Browser* browser) override;
  48
  49   Browser* browser_;
  50   sessions::TabRestoreService* tab_restore_service_;
  51
  52   DISALLOW_COPY_AND_ASSIGN(BrowserTabRestorer);
  53 };
  54
  55 BrowserTabRestorer::~BrowserTabRestorer() {
  56   tab_restore_service_->RemoveObserver(this);
  57   BrowserList::GetInstance(browser_->host_desktop_type())->RemoveObserver(this);
  58 }
  59
  60 // static
  61 void BrowserTabRestorer::CreateIfNecessary(Browser* browser) {
  62   DCHECK(browser);
  63   if (browser->profile()->GetUserData(kBrowserTabRestorerKey))
  64     return;  // Only allow one restore for a given profile at a time.
  65
  66   // BrowserTabRestorer is deleted at the appropriate time.
  67   new BrowserTabRestorer(browser);
  68 }
  69
  70 BrowserTabRestorer::BrowserTabRestorer(Browser* browser)
  71     : browser_(browser),
  72       tab_restore_service_(
  73           TabRestoreServiceFactory::GetForProfile(browser->profile())) {
  74   DCHECK(tab_restore_service_);
  75   DCHECK(!tab_restore_service_->IsLoaded());
  76   tab_restore_service_->AddObserver(this);
  77   BrowserList::GetInstance(browser->host_desktop_type())->AddObserver(this);
  78   browser_->profile()->SetUserData(kBrowserTabRestorerKey, this);
  79   tab_restore_service_->LoadTabsFromLastSession();
  80 }
  81
  82 void BrowserTabRestorer::TabRestoreServiceChanged(
  83     sessions::TabRestoreService* service) {}
  84
  85 void BrowserTabRestorer::TabRestoreServiceDestroyed(
  86     sessions::TabRestoreService* service) {}
  87
  88 void BrowserTabRestorer::TabRestoreServiceLoaded(
  89     sessions::TabRestoreService* service) {
  90   RestoreTab(browser_);
  91   // This deletes us.
  92   browser_->profile()->SetUserData(kBrowserTabRestorerKey, NULL);
  93 }
  94
  95 void BrowserTabRestorer::OnBrowserRemoved(Browser* browser) {
  96   // This deletes us.
  97   browser_->profile()->SetUserData(kBrowserTabRestorerKey, NULL);
  98 }
  99
 100 }  // namespace
 101
 102 void RestoreTab(Browser* browser) {
 103   content::RecordAction(base::UserMetricsAction("RestoreTab"));
 104   sessions::TabRestoreService* service =
 105       TabRestoreServiceFactory::GetForProfile(browser->profile());
 106   if (!service)
 107     return;
 108
 109   if (service->IsLoaded()) {
 110     service->RestoreMostRecentEntry(browser->tab_restore_service_delegate(),
 111                                     browser->host_desktop_type());
 112     return;
 113   }
 114
 115   BrowserTabRestorer::CreateIfNecessary(browser);
 116 }
 117
 118 }  // namespace chrome