Move files instead of copying them.

chrome/installer/util/move_tree_work_item.cc

+// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/installer/util/move_tree_work_item.h"
+
+#include <shlwapi.h>
+#include "base/file_util.h"
+#include "chrome/installer/util/logging_installer.h"
+
+MoveTreeWorkItem::~MoveTreeWorkItem() {
+  if (file_util::PathExists(backup_path_)) {
+    file_util::Delete(backup_path_, true);
+  }
+}
+
+MoveTreeWorkItem::MoveTreeWorkItem(const std::wstring& source_path,
+                                   const std::wstring& dest_path,
+                                   const std::wstring& temp_dir)
+    : source_path_(source_path),
+      dest_path_(dest_path),
+      temp_dir_(temp_dir),
+      moved_to_dest_path_(false),
+      moved_to_backup_(false) {
+}
+
+bool MoveTreeWorkItem::Do() {
+  if (!file_util::PathExists(source_path_)) {
+    LOG(ERROR) << source_path_ << " does not exist";
+    return false;
+  }
+
+  // If dest_path_ exists, move destination to a backup path.
+  if (file_util::PathExists(dest_path_)) {
+    // Generate a backup path that can keep the original files under dest_path_.
+    if (!file_util::CreateTemporaryFileNameInDir(temp_dir_, &backup_path_)) {
+      LOG(ERROR) << "Failed to get backup path in folder " << temp_dir_;
+      return false;
+    }
+
+    if (file_util::Move(dest_path_, backup_path_)) {
+      moved_to_backup_ = true;
+      LOG(INFO) << "Moved destination " << dest_path_
+                << " to backup path " << backup_path_;
+    } else {
+      LOG(ERROR) << "failed moving " << dest_path_ << " to " << backup_path_;
+      return false;
+    }
+  }
+
+  // Now move source to destination.
+  if (file_util::Move(source_path_, dest_path_)) {
+    moved_to_dest_path_ = true;
+    LOG(INFO) << "Moved source " << source_path_
+              << " to destination " << dest_path_;
+  } else {
+    LOG(ERROR) << "failed move " << source_path_ << " to " << dest_path_;
+    return false;
+  }
+
+  return true;
+}
+
+void MoveTreeWorkItem::Rollback() {
+  if (moved_to_dest_path_ && !file_util::Move(dest_path_, source_path_))
+    LOG(ERROR) << "Can not move " << dest_path_ << " to " << source_path_;
+
+  if (moved_to_backup_ && !file_util::Move(backup_path_, dest_path_))
+    LOG(ERROR) << "failed move " << backup_path_ << " to " << dest_path_;
+}