chrome/installer/util/delete_reg_value_work_item.cc

   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 #include "chrome/installer/util/delete_reg_value_work_item.h"
   6
   7 #include "base/logging.h"
   8 #include "base/strings/string_util.h"
   9 #include "base/win/registry.h"
  10 #include "chrome/installer/util/logging_installer.h"
  11
  12 using base::win::RegKey;
  13
  14 DeleteRegValueWorkItem::DeleteRegValueWorkItem(HKEY predefined_root,
  15                                                const std::wstring& key_path,
  16                                                REGSAM wow64_access,
  17                                                const std::wstring& value_name)
  18     : predefined_root_(predefined_root),
  19       key_path_(key_path),
  20       value_name_(value_name),
  21       wow64_access_(wow64_access),
  22       previous_type_(0),
  23       status_(DELETE_VALUE) {
  24   DCHECK(wow64_access == 0 ||
  25          wow64_access == KEY_WOW64_32KEY ||
  26          wow64_access == KEY_WOW64_64KEY);
  27 }
  28
  29 DeleteRegValueWorkItem::~DeleteRegValueWorkItem() {
  30 }
  31
  32 bool DeleteRegValueWorkItem::Do() {
  33   if (status_ != DELETE_VALUE) {
  34     // we already did something.
  35     LOG(ERROR) << "multiple calls to Do()";
  36     return false;
  37   }
  38
  39   status_ = VALUE_UNCHANGED;
  40
  41   RegKey key;
  42   DWORD type = 0;
  43   DWORD size = 0;
  44   LONG result = key.Open(predefined_root_,
  45                          key_path_.c_str(),
  46                          KEY_READ | KEY_WRITE | wow64_access_);
  47   if (result == ERROR_SUCCESS)
  48     result = key.ReadValue(value_name_.c_str(), NULL, &size, &type);
  49
  50   if (result == ERROR_FILE_NOT_FOUND) {
  51     LOG(INFO) << "(delete value) Key: " << key_path_ << " or Value: "
  52               << value_name_ << " does not exist.";
  53     status_ = VALUE_NOT_FOUND;
  54     return true;
  55   }
  56
  57   if (result == ERROR_SUCCESS) {
  58     if (!size) {
  59       previous_type_ = type;
  60     } else {
  61       previous_value_.resize(size);
  62       result = key.ReadValue(value_name_.c_str(), &previous_value_[0], &size,
  63                              &previous_type_);
  64       if (result != ERROR_SUCCESS) {
  65         previous_value_.erase();
  66         VLOG(1) << "Failed to save original value. Error: " << result;
  67       }
  68     }
  69   }
  70
  71   result = key.DeleteValue(value_name_.c_str());
  72   if (result != ERROR_SUCCESS) {
  73     VLOG(1) << "Failed to delete value " << value_name_ << " error: " << result;
  74     return false;
  75   }
  76
  77   status_ = VALUE_DELETED;
  78   return true;
  79 }
  80
  81 void DeleteRegValueWorkItem::Rollback() {
  82   if (status_ == DELETE_VALUE || status_ == VALUE_ROLLED_BACK)
  83     return;
  84   if (status_ == VALUE_UNCHANGED || status_ == VALUE_NOT_FOUND) {
  85     status_ = VALUE_ROLLED_BACK;
  86     VLOG(1) << "rollback: setting unchanged, nothing to do";
  87     return;
  88   }
  89
  90   // At this point only possible state is VALUE_DELETED.
  91   RegKey key;
  92   LONG result = key.Open(predefined_root_,
  93                          key_path_.c_str(),
  94                          KEY_READ | KEY_WRITE | wow64_access_);
  95   if (result == ERROR_SUCCESS) {
  96     // try to restore the previous value
  97     DWORD previous_size = static_cast<DWORD>(previous_value_.size());
  98     const char* previous_value =
  99         previous_size ? &previous_value_[0] : NULL;
 100     result = key.WriteValue(value_name_.c_str(), previous_value,
 101                             previous_size, previous_type_);
 102     VLOG_IF(1, result != ERROR_SUCCESS) << "rollback: restoring "
 103                                         << value_name_ << " error: " << result;
 104   } else {
 105     VLOG(1) << "can not open " << key_path_ << " error: " << result;
 106   }
 107 }