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