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      1 // Copyright (c) 2010 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/installer/util/delete_reg_key_work_item.h"
      6 
      7 #include <shlwapi.h>
      8 
      9 #include "base/logging.h"
     10 #include "base/win/registry.h"
     11 #include "chrome/installer/util/install_util.h"
     12 
     13 using base::win::RegKey;
     14 
     15 DeleteRegKeyWorkItem::~DeleteRegKeyWorkItem() {
     16 }
     17 
     18 DeleteRegKeyWorkItem::DeleteRegKeyWorkItem(HKEY predefined_root,
     19                                            const std::wstring& path,
     20                                            REGSAM wow64_access)
     21     : predefined_root_(predefined_root),
     22       path_(path),
     23       wow64_access_(wow64_access) {
     24   DCHECK(predefined_root);
     25   // It's a safe bet that we don't want to delete one of the root trees.
     26   DCHECK(!path.empty());
     27   DCHECK(wow64_access == 0 ||
     28          wow64_access == KEY_WOW64_32KEY ||
     29          wow64_access == KEY_WOW64_64KEY);
     30 }
     31 
     32 bool DeleteRegKeyWorkItem::Do() {
     33   if (path_.empty())
     34     return false;
     35 
     36   RegistryKeyBackup backup;
     37 
     38   // Only try to make a backup if we're not configured to ignore failures.
     39   if (!ignore_failure_) {
     40     if (!backup.Initialize(predefined_root_, path_.c_str(), wow64_access_)) {
     41       LOG(ERROR) << "Failed to backup destination for registry key copy.";
     42       return false;
     43     }
     44   }
     45 
     46   // Delete the key.
     47   if (!InstallUtil::DeleteRegistryKey(
     48           predefined_root_, path_.c_str(), wow64_access_)) {
     49     return ignore_failure_;
     50   }
     51 
     52   // We've succeeded, so remember any backup we may have made.
     53   backup_.swap(backup);
     54 
     55   return true;
     56 }
     57 
     58 void DeleteRegKeyWorkItem::Rollback() {
     59   if (ignore_failure_)
     60     return;
     61 
     62   // Delete anything in the key before restoring the backup in case someone else
     63   // put new data in the key after Do().
     64   InstallUtil::DeleteRegistryKey(predefined_root_,
     65                                  path_.c_str(),
     66                                  wow64_access_);
     67 
     68   // Restore the old contents.  The restoration takes on its default security
     69   // attributes; any custom attributes are lost.
     70   if (!backup_.WriteTo(predefined_root_, path_.c_str(), wow64_access_))
     71     LOG(ERROR) << "Failed to restore key in rollback.";
     72 }
     73