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      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 "chrome/browser/sync/backup_rollback_controller.h"
      6 
      7 #include "base/command_line.h"
      8 #include "base/message_loop/message_loop.h"
      9 #include "base/metrics/field_trial.h"
     10 #include "chrome/browser/sync/supervised_user_signin_manager_wrapper.h"
     11 #include "chrome/common/chrome_switches.h"
     12 #include "components/sync_driver/sync_prefs.h"
     13 
     14 namespace browser_sync {
     15 
     16 #if defined(ENABLE_PRE_SYNC_BACKUP)
     17 // Number of rollback attempts to try before giving up.
     18 static const int kRollbackLimits = 3;
     19 
     20 // Finch experiment name and group.
     21 static char kSyncBackupFinchName[] = "SyncBackup";
     22 static char kSyncBackupFinchDisabled[] = "disabled";
     23 #endif
     24 
     25 BackupRollbackController::BackupRollbackController(
     26     sync_driver::SyncPrefs* sync_prefs,
     27     const SupervisedUserSigninManagerWrapper* signin,
     28     base::Closure start_backup,
     29     base::Closure start_rollback)
     30     : sync_prefs_(sync_prefs),
     31       signin_(signin),
     32       start_backup_(start_backup),
     33       start_rollback_(start_rollback) {
     34 }
     35 
     36 BackupRollbackController::~BackupRollbackController() {
     37 }
     38 
     39 bool BackupRollbackController::StartBackup() {
     40   if (!IsBackupEnabled())
     41     return false;
     42 
     43   // Disable rollback to previous backup DB because it will be overwritten by
     44   // new backup.
     45   sync_prefs_->SetRemainingRollbackTries(0);
     46   base::MessageLoop::current()->PostTask(FROM_HERE, start_backup_);
     47   return true;
     48 }
     49 
     50 bool BackupRollbackController::StartRollback() {
     51   if (!IsBackupEnabled())
     52     return false;
     53 
     54   // Don't roll back if disabled or user is signed in.
     55   if (CommandLine::ForCurrentProcess()->HasSwitch(
     56           switches::kSyncDisableRollback) ||
     57       !signin_->GetEffectiveUsername().empty()) {
     58     sync_prefs_->SetRemainingRollbackTries(0);
     59     return false;
     60   }
     61 
     62   int rollback_tries = sync_prefs_->GetRemainingRollbackTries();
     63   if (rollback_tries <= 0)
     64     return false;   // No pending rollback.
     65 
     66   sync_prefs_->SetRemainingRollbackTries(rollback_tries - 1);
     67   base::MessageLoop::current()->PostTask(FROM_HERE, start_rollback_);
     68   return true;
     69 }
     70 
     71 void BackupRollbackController::OnRollbackReceived() {
     72 #if defined(ENABLE_PRE_SYNC_BACKUP)
     73   sync_prefs_->SetRemainingRollbackTries(kRollbackLimits);
     74 #endif
     75 }
     76 
     77 void BackupRollbackController::OnRollbackDone() {
     78 #if defined(ENABLE_PRE_SYNC_BACKUP)
     79   sync_prefs_->SetRemainingRollbackTries(0);
     80 #endif
     81 }
     82 
     83 // static
     84 bool BackupRollbackController::IsBackupEnabled() {
     85 #if defined(ENABLE_PRE_SYNC_BACKUP)
     86   const std::string group_name =
     87       base::FieldTrialList::FindFullName(kSyncBackupFinchName);
     88 
     89   if (CommandLine::ForCurrentProcess()->HasSwitch(
     90           switches::kSyncDisableBackup) ||
     91       group_name == kSyncBackupFinchDisabled)  {
     92     return false;
     93   }
     94   return true;
     95 #else
     96   return false;
     97 #endif
     98 }
     99 
    100 }  // namespace browser_sync
    101