src/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 (StartsWithASCII(key, kServiceMetadataKey, true) ||
  50         StartsWithASCII(key, kFileMetadataKeyPrefix, true) ||
  51         StartsWithASCII(key, kFileTrackerKeyPrefix, true)) {
  52       continue;
  53     }
  54
  55     // Drop entries used in version 4 only.
  56     if (StartsWithASCII(key, kAppRootIDByAppIDKeyPrefix, true) ||
  57         StartsWithASCII(key, kActiveTrackerIDByFileIDKeyPrefix, true) ||
  58         StartsWithASCII(key, kTrackerIDByFileIDKeyPrefix, true) ||
  59         StartsWithASCII(key, kMultiTrackerByFileIDKeyPrefix, true) ||
  60         StartsWithASCII(key, kActiveTrackerIDByParentAndTitleKeyPrefix, true) ||
  61         StartsWithASCII(key, kTrackerIDByParentAndTitleKeyPrefix, true) ||
  62         StartsWithASCII(key, kMultiBackingParentAndTitleKeyPrefix, true) ||
  63         StartsWithASCII(key, kDirtyIDKeyPrefix, true) ||
  64         StartsWithASCII(key, kDemotedDirtyIDKeyPrefix, true)) {
  65       write_batch.Delete(key);
  66       continue;
  67     }
  68
  69     DVLOG(3) << "Unknown key: " << key << " was found.";
  70   }
  71
  72   return LevelDBStatusToSyncStatusCode(
  73       db->Write(leveldb::WriteOptions(), &write_batch));
  74 }
  75
  76 }  // namespace drive_backend
  77 }  // namespace sync_file_system