metadata_db_migration_util.cc revision 1320f92c476a1ad9d19dba2a48c72b75566198e9 
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
17namespace sync_file_system {
18namespace drive_backend {
19
20SyncStatusCode 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
78