chrome/installer/util/copy_tree_work_item.h

   1 // Copyright (c) 2011 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 #ifndef CHROME_INSTALLER_UTIL_COPY_TREE_WORK_ITEM_H_
   6 #define CHROME_INSTALLER_UTIL_COPY_TREE_WORK_ITEM_H_
   7
   8 #include "base/files/file_path.h"
   9 #include "base/files/scoped_temp_dir.h"
  10 #include "base/gtest_prod_util.h"
  11 #include "chrome/installer/util/work_item.h"
  12
  13 // A WorkItem subclass that recursively copies a file system hierarchy from
  14 // source path to destination path. It also creates all necessary intermediate
  15 // paths of the destination path if they do not exist. The file system
  16 // hierarchy could be a single file, or a directory.
  17 // Under the cover CopyTreeWorkItem moves the destination path, if existing,
  18 // to the temporary directory passed in, and then copies the source hierarchy
  19 // to the destination location. During rollback the original destination
  20 // hierarchy is moved back.
  21 // NOTE: It is a best practice to ensure that the temporary directory is on the
  22 // same volume as the destination path.  If this is not the case, the existing
  23 // destination path is not moved, but rather copied, to the destination path.
  24 // This will result in in-use files being left behind, as well as potentially
  25 // losing ACLs or other metadata in the case of a rollback.
  26 class CopyTreeWorkItem : public WorkItem {
  27  public:
  28   ~CopyTreeWorkItem() override;
  29
  30   bool Do() override;
  31
  32   void Rollback() override;
  33
  34  private:
  35   friend class WorkItem;
  36
  37   // See comments on corresponding member variables for the semantics of
  38   // arguments.
  39   // Notes on temp_path: to facilitate rollback, the caller needs to supply
  40   // a temporary directory to save the original files if they exist under
  41   // dest_path.
  42   CopyTreeWorkItem(const base::FilePath& source_path,
  43                    const base::FilePath& dest_path,
  44                    const base::FilePath& temp_dir,
  45                    CopyOverWriteOption overwrite_option,
  46                    const base::FilePath& alternative_path);
  47
  48   // Checks if the path specified is in use (and hence can not be deleted)
  49   bool IsFileInUse(const base::FilePath& path);
  50
  51   // Source path to copy files from.
  52   base::FilePath source_path_;
  53
  54   // Destination path to copy files to.
  55   base::FilePath dest_path_;
  56
  57   // Temporary directory that can be used.
  58   base::FilePath temp_dir_;
  59
  60   // Controls the behavior for overwriting.
  61   CopyOverWriteOption overwrite_option_;
  62
  63   // If overwrite_option_ = NEW_NAME_IF_IN_USE, this variables stores the path
  64   // to be used if the file is in use and hence we want to copy it to a
  65   // different path.
  66   base::FilePath alternative_path_;
  67
  68   // Whether the source was copied to dest_path_
  69   bool copied_to_dest_path_;
  70
  71   // Whether the original files have been moved to backup path under
  72   // temporary directory. If true, moving back is needed during rollback.
  73   bool moved_to_backup_;
  74
  75   // Whether the source was copied to alternative_path_ because dest_path_
  76   // existed and was in use. Needed during rollback.
  77   bool copied_to_alternate_path_;
  78
  79   // The temporary directory into which the original dest_path_ has been moved.
  80   base::ScopedTempDir backup_path_;
  81
  82   FRIEND_TEST_ALL_PREFIXES(CopyTreeWorkItemTest, CopyFileSameContent);
  83   FRIEND_TEST_ALL_PREFIXES(CopyTreeWorkItemTest, CopyFileInUse);
  84   FRIEND_TEST_ALL_PREFIXES(CopyTreeWorkItemTest, CopyFileAndCleanup);
  85   FRIEND_TEST_ALL_PREFIXES(CopyTreeWorkItemTest, NewNameAndCopyTest);
  86   FRIEND_TEST_ALL_PREFIXES(CopyTreeWorkItemTest, CopyFileInUseAndCleanup);
  87 };
  88
  89 #endif  // CHROME_INSTALLER_UTIL_COPY_TREE_WORK_ITEM_H_