chrome/browser/sync_file_system/drive_backend/metadata_db_migration_util.cc

   1 // Copyright 2013 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/browser/sync_file_system/drive_backend/metadata_db_migration_util.h"
   6
   7 #include "base/files/file_path.h"
   8 #include "base/memory/scoped_ptr.h"
   9 #include "base/strings/string_util.h"
  10 #include "chrome/browser/sync_file_system/drive_backend/drive_backend_util.h"
  11 #include "storage/common/fileapi/file_system_types.h"
  12 #include "storage/common/fileapi/file_system_util.h"
  13 #include "third_party/leveldatabase/src/include/leveldb/db.h"
  14 #include "third_party/leveldatabase/src/include/leveldb/write_batch.h"
  15 #include "url/gurl.h"
  16
  17 namespace sync_file_system {
  18 namespace drive_backend {
  19
  20 SyncStatusCode MigrateDatabaseFromV4ToV3(leveldb::DB* db) {
  21   // Rollback from version 4 to version 3.
  22   // Please see metadata_database_index.cc for version 3 format, and
  23   // metadata_database_index_on_disk.cc for version 4 format.
  24
  25   const char kDatabaseVersionKey[] = "VERSION";
  26   const char kServiceMetadataKey[] = "SERVICE";
  27   const char kFileMetadataKeyPrefix[] = "FILE: ";
  28   const char kFileTrackerKeyPrefix[] = "TRACKER: ";
  29
  30   // Key prefixes used in version 4.
  31   const char kAppRootIDByAppIDKeyPrefix[] = "APP_ROOT: ";
  32   const char kActiveTrackerIDByFileIDKeyPrefix[] = "ACTIVE_FILE: ";
  33   const char kTrackerIDByFileIDKeyPrefix[] = "TRACKER_FILE: ";
  34   const char kMultiTrackerByFileIDKeyPrefix[] = "MULTI_FILE: ";
  35   const char kActiveTrackerIDByParentAndTitleKeyPrefix[] = "ACTIVE_PATH: ";
  36   const char kTrackerIDByParentAndTitleKeyPrefix[] = "TRACKER_PATH: ";
  37   const char kMultiBackingParentAndTitleKeyPrefix[] = "MULTI_PATH: ";
  38   const char kDirtyIDKeyPrefix[] = "DIRTY: ";
  39   const char kDemotedDirtyIDKeyPrefix[] = "DEMOTED_DIRTY: ";
  40
  41   leveldb::WriteBatch write_batch;
  42   write_batch.Put(kDatabaseVersionKey, "3");
  43
  44   scoped_ptr<leveldb::Iterator> itr(db->NewIterator(leveldb::ReadOptions()));
  45   for (itr->SeekToFirst(); itr->Valid(); itr->Next()) {
  46     std::string key = itr->key().ToString();
  47
  48     // Do nothing for valid entries in both versions.
  49     if (base::StartsWith(key, kServiceMetadataKey,
  50                          base::CompareCase::SENSITIVE) ||
  51         base::StartsWith(key, kFileMetadataKeyPrefix,
  52                          base::CompareCase::SENSITIVE) ||
  53         base::StartsWith(key, kFileTrackerKeyPrefix,
  54                          base::CompareCase::SENSITIVE)) {
  55       continue;
  56     }
  57
  58     // Drop entries used in version 4 only.
  59     if (base::StartsWith(key, kAppRootIDByAppIDKeyPrefix,
  60                          base::CompareCase::SENSITIVE) ||
  61         base::StartsWith(key, kActiveTrackerIDByFileIDKeyPrefix,
  62                          base::CompareCase::SENSITIVE) ||
  63         base::StartsWith(key, kTrackerIDByFileIDKeyPrefix,
  64                          base::CompareCase::SENSITIVE) ||
  65         base::StartsWith(key, kMultiTrackerByFileIDKeyPrefix,
  66                          base::CompareCase::SENSITIVE) ||
  67         base::StartsWith(key, kActiveTrackerIDByParentAndTitleKeyPrefix,
  68                          base::CompareCase::SENSITIVE) ||
  69         base::StartsWith(key, kTrackerIDByParentAndTitleKeyPrefix,
  70                          base::CompareCase::SENSITIVE) ||
  71         base::StartsWith(key, kMultiBackingParentAndTitleKeyPrefix,
  72                          base::CompareCase::SENSITIVE) ||
  73         base::StartsWith(key, kDirtyIDKeyPrefix,
  74                          base::CompareCase::SENSITIVE) ||
  75         base::StartsWith(key, kDemotedDirtyIDKeyPrefix,
  76                          base::CompareCase::SENSITIVE)) {
  77       write_batch.Delete(key);
  78       continue;
  79     }
  80
  81     DVLOG(3) << "Unknown key: " << key << " was found.";
  82   }
  83
  84   return LevelDBStatusToSyncStatusCode(
  85       db->Write(leveldb::WriteOptions(), &write_batch));
  86 }
  87
  88 }  // namespace drive_backend
  89 }  // namespace sync_file_system