[SyncFS] Rollback function from version 4 to version 3.

Make a routine, but it is not called.


BUG=347425
TEST=./unit_tests --gtest_filter="DriveMetadata*"

Review URL: https://codereview.chromium.org/446653003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@288012 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/sync_file_system/drive_backend/metadata_db_migration_util.cc

@@ -244,5 +244,61 @@ SyncStatusCode MigrateDatabaseFromV1ToV2(leveldb::DB* db) {
       db->Write(leveldb::WriteOptions(), &write_batch));
 }
 
+SyncStatusCode MigrateDatabaseFromV4ToV3(leveldb::DB* db) {
+  // Rollback from version 4 to version 3.
+  // Please see metadata_database_index.cc for version 3 format, and
+  // metadata_database_index_on_disk.cc for version 4 format.
+
+  const char kDatabaseVersionKey[] = "VERSION";
+  const char kServiceMetadataKey[] = "SERVICE";
+  const char kFileMetadataKeyPrefix[] = "FILE: ";
+  const char kFileTrackerKeyPrefix[] = "TRACKER: ";
+
+  // Key prefixes used in version 4.
+  const char kAppRootIDByAppIDKeyPrefix[] = "APP_ROOT: ";
+  const char kActiveTrackerIDByFileIDKeyPrefix[] = "ACTIVE_FILE: ";
+  const char kTrackerIDByFileIDKeyPrefix[] = "TRACKER_FILE: ";
+  const char kMultiTrackerByFileIDKeyPrefix[] = "MULTI_FILE: ";
+  const char kActiveTrackerIDByParentAndTitleKeyPrefix[] = "ACTIVE_PATH: ";
+  const char kTrackerIDByParentAndTitleKeyPrefix[] = "TRACKER_PATH: ";
+  const char kMultiBackingParentAndTitleKeyPrefix[] = "MULTI_PATH: ";
+  const char kDirtyIDKeyPrefix[] = "DIRTY: ";
+  const char kDemotedDirtyIDKeyPrefix[] = "DEMOTED_DIRTY: ";
+
+  leveldb::WriteBatch write_batch;
+  write_batch.Put(kDatabaseVersionKey, "3");
+
+  scoped_ptr<leveldb::Iterator> itr(db->NewIterator(leveldb::ReadOptions()));
+  for (itr->SeekToFirst(); itr->Valid(); itr->Next()) {
+    std::string key = itr->key().ToString();
+
+    // Do nothing for valid entries in both versions.
+    if (StartsWithASCII(key, kServiceMetadataKey, true) ||
+        StartsWithASCII(key, kFileMetadataKeyPrefix, true) ||
+        StartsWithASCII(key, kFileTrackerKeyPrefix, true)) {
+      continue;
+    }
+
+    // Drop entries used in version 4 only.
+    if (StartsWithASCII(key, kAppRootIDByAppIDKeyPrefix, true) ||
+        StartsWithASCII(key, kActiveTrackerIDByFileIDKeyPrefix, true) ||
+        StartsWithASCII(key, kTrackerIDByFileIDKeyPrefix, true) ||
+        StartsWithASCII(key, kMultiTrackerByFileIDKeyPrefix, true) ||
+        StartsWithASCII(key, kActiveTrackerIDByParentAndTitleKeyPrefix, true) ||
+        StartsWithASCII(key, kTrackerIDByParentAndTitleKeyPrefix, true) ||
+        StartsWithASCII(key, kMultiBackingParentAndTitleKeyPrefix, true) ||
+        StartsWithASCII(key, kDirtyIDKeyPrefix, true) ||
+        StartsWithASCII(key, kDemotedDirtyIDKeyPrefix, true)) {
+      write_batch.Delete(key);
+      continue;
+    }
+
+    DVLOG(3) << "Unknown key: " << key << " was found.";
+  }
+
+  return LevelDBStatusToSyncStatusCode(
+      db->Write(leveldb::WriteOptions(), &write_batch));
+}
+
 }  // namespace drive_backend
 }  // namespace sync_file_system

chrome/browser/sync_file_system/drive_backend/metadata_db_migration_util.h

@@ -58,6 +58,9 @@ SyncStatusCode MigrateDatabaseFromV0ToV1(leveldb::DB* db);
 // Migrate |db| schema from version 1 to version 2.
 SyncStatusCode MigrateDatabaseFromV1ToV2(leveldb::DB* db);
 
+// Rollback |db| schema from version 4 to version 3.
+SyncStatusCode MigrateDatabaseFromV4ToV3(leveldb::DB* db);
+
 }  // namespace drive_backend
 }  // namespace sync_file_system
 

chrome/browser/sync_file_system/drive_backend/metadata_db_migration_util_unittest.cc

@@ -45,6 +45,24 @@ bool CreateV0SerializedSyncableFileSystemURL(
   return true;
 }
 
+void VerifyKeyAndValue(const std::string& key,
+                       const std::string& expect_val,
+                       leveldb::DB* db) {
+  scoped_ptr<leveldb::Iterator> itr(db->NewIterator(leveldb::ReadOptions()));
+
+  itr->Seek(key);
+  EXPECT_TRUE(itr->Valid());
+  EXPECT_EQ(expect_val, itr->value().ToString());
+}
+
+void VerifyNotExist(const std::string& key, leveldb::DB* db) {
+  scoped_ptr<leveldb::Iterator> itr(db->NewIterator(leveldb::ReadOptions()));
+
+  itr->Seek(key);
+  EXPECT_TRUE(!itr->Valid() ||
+              !StartsWithASCII(itr->key().ToString(), key, true));
+}
+
 }  // namespace
 
 TEST(DriveMetadataDBMigrationUtilTest, ParseV0FormatFileSystemURL) {
@@ -309,5 +327,83 @@ TEST(DriveMetadataDBMigrationUtilTest, MigrationFromV1) {
   EXPECT_EQ(RemoveWapiIdPrefix(kResourceId3), itr->value().ToString());
 }
 
+TEST(DriveMetadataDBMigrationUtilTest, RollbackFromV4ToV3) {
+  // Rollback from version 4 to version 3.
+  // Please see metadata_database_index.cc for version 3 format, and
+  // metadata_database_index_on_disk.cc for version 4 format.
+
+  const char kDatabaseVersionKey[] = "VERSION";
+  const char kServiceMetadataKey[] = "SERVICE";
+  const char kFileMetadataKeyPrefix[] = "FILE: ";
+  const char kFileTrackerKeyPrefix[] = "TRACKER: ";
+
+  // Key prefixes used in version 4.
+  const char kAppRootIDByAppIDKeyPrefix[] = "APP_ROOT: ";
+  const char kActiveTrackerIDByFileIDKeyPrefix[] = "ACTIVE_FILE: ";
+  const char kTrackerIDByFileIDKeyPrefix[] = "TRACKER_FILE: ";
+  const char kMultiTrackerByFileIDKeyPrefix[] = "MULTI_FILE: ";
+  const char kActiveTrackerIDByParentAndTitleKeyPrefix[] = "ACTIVE_PATH: ";
+  const char kTrackerIDByParentAndTitleKeyPrefix[] = "TRACKER_PATH: ";
+  const char kMultiBackingParentAndTitleKeyPrefix[] = "MULTI_PATH: ";
+  const char kDirtyIDKeyPrefix[] = "DIRTY: ";
+  const char kDemotedDirtyIDKeyPrefix[] = "DEMOTED_DIRTY: ";
+
+  // Set up environment.
+  leveldb::DB* db_ptr = NULL;
+  {
+    base::ScopedTempDir base_dir;
+    ASSERT_TRUE(base_dir.CreateUniqueTempDir());
+
+    leveldb::Options options;
+    options.create_if_missing = true;
+    std::string db_dir = fileapi::FilePathToString(
+        base_dir.path().Append(DriveMetadataStore::kDatabaseName));
+    leveldb::Status status = leveldb::DB::Open(options, db_dir, &db_ptr);
+    ASSERT_TRUE(status.ok());
+  }
+  scoped_ptr<leveldb::DB> db(db_ptr);
+
+  // Setup the database with the schema version 4, without IDs.
+  leveldb::WriteBatch batch;
+  batch.Put(kDatabaseVersionKey, "4");
+  batch.Put(kServiceMetadataKey, "service_metadata");
+  batch.Put(kFileMetadataKeyPrefix, "file_metadata");
+  batch.Put(kFileTrackerKeyPrefix, "file_tracker");
+  batch.Put(kAppRootIDByAppIDKeyPrefix, "app_root_id");
+  batch.Put(kActiveTrackerIDByFileIDKeyPrefix, "active_id_by_file");
+  batch.Put(kTrackerIDByFileIDKeyPrefix, "tracker_id_by_file");
+  batch.Put(kMultiTrackerByFileIDKeyPrefix, "multi_tracker_by_file");
+  batch.Put(kActiveTrackerIDByParentAndTitleKeyPrefix, "active_id_by_path");
+  batch.Put(kTrackerIDByParentAndTitleKeyPrefix, "tracker_id_by_path");
+  batch.Put(kMultiBackingParentAndTitleKeyPrefix, "multi_tracker_by_path");
+  batch.Put(kDirtyIDKeyPrefix, "dirty");
+  batch.Put(kDemotedDirtyIDKeyPrefix, "demoted_dirty");
+
+  leveldb::Status status = db->Write(leveldb::WriteOptions(), &batch);
+  EXPECT_EQ(SYNC_STATUS_OK, LevelDBStatusToSyncStatusCode(status));
+
+  // Migrate the database.
+  MigrateDatabaseFromV4ToV3(db.get());
+
+  // Verify DB schema verison
+  VerifyKeyAndValue(kDatabaseVersionKey, "3", db.get());
+
+  // Verify remained entries.
+  VerifyKeyAndValue(kServiceMetadataKey, "service_metadata", db.get());
+  VerifyKeyAndValue(kFileMetadataKeyPrefix, "file_metadata", db.get());
+  VerifyKeyAndValue(kFileTrackerKeyPrefix, "file_tracker", db.get());
+
+  // Verify
+  VerifyNotExist(kAppRootIDByAppIDKeyPrefix, db.get());
+  VerifyNotExist(kActiveTrackerIDByFileIDKeyPrefix, db.get());
+  VerifyNotExist(kTrackerIDByFileIDKeyPrefix, db.get());
+  VerifyNotExist(kMultiTrackerByFileIDKeyPrefix, db.get());
+  VerifyNotExist(kActiveTrackerIDByParentAndTitleKeyPrefix, db.get());
+  VerifyNotExist(kTrackerIDByParentAndTitleKeyPrefix, db.get());
+  VerifyNotExist(kMultiBackingParentAndTitleKeyPrefix, db.get());
+  VerifyNotExist(kDirtyIDKeyPrefix, db.get());
+  VerifyNotExist(kDemotedDirtyIDKeyPrefix, db.get());
+}
+
 }  // namespace drive_backend
 }  // namespace sync_file_system