[SyncFS] Migrate version management from MDDB to index classes.

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

Review URL: https://codereview.chromium.org/393953010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@283705 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/sync_file_system/drive_backend/drive_backend_constants.cc

@@ -16,6 +16,7 @@ const base::FilePath::CharType kDatabaseName[] =
 
 const char kDatabaseVersionKey[] = "VERSION";
 const int64 kCurrentDatabaseVersion = 3;
+const int64 kDatabaseOnDiskVersion = 4;
 const char kServiceMetadataKey[] = "SERVICE";
 const char kFileMetadataKeyPrefix[] = "FILE: ";
 const char kFileTrackerKeyPrefix[] = "TRACKER: ";

chrome/browser/sync_file_system/drive_backend/drive_backend_constants.h

@@ -18,6 +18,7 @@ extern const base::FilePath::CharType kDatabaseName[];
 
 extern const char kDatabaseVersionKey[];
 extern const int64 kCurrentDatabaseVersion;
+extern const int64 kDatabaseOnDiskVersion;
 extern const char kServiceMetadataKey[];
 extern const char kFileMetadataKeyPrefix[];
 extern const char kFileTrackerKeyPrefix[];

chrome/browser/sync_file_system/drive_backend/drive_backend_util.cc

@@ -21,6 +21,11 @@
 namespace sync_file_system {
 namespace drive_backend {
 
+void PutVersionToBatch(int64 version, leveldb::WriteBatch* batch) {
+  if (batch)
+    batch->Put(kDatabaseVersionKey, base::Int64ToString(version));
+}
+
 void PutServiceMetadataToBatch(const ServiceMetadata& service_metadata,
                                leveldb::WriteBatch* batch) {
   if (!batch)

chrome/browser/sync_file_system/drive_backend/drive_backend_util.h

@@ -30,6 +30,8 @@ class WriteBatch;
 namespace sync_file_system {
 namespace drive_backend {
 
+void PutVersionToBatch(int64 version, leveldb::WriteBatch* batch);
+
 void PutServiceMetadataToBatch(const ServiceMetadata& service_metadata,
                                leveldb::WriteBatch* batch);
 void PutFileMetadataToBatch(const FileMetadata& file,

chrome/browser/sync_file_system/drive_backend/metadata_database.cc

@@ -284,15 +284,6 @@ SyncStatusCode MigrateDatabaseIfNeeded(leveldb::DB* db) {
   }
 }
 
-SyncStatusCode WriteVersionInfo(leveldb::DB* db) {
-  base::ThreadRestrictions::AssertIOAllowed();
-  DCHECK(db);
-  return LevelDBStatusToSyncStatusCode(
-      db->Put(leveldb::WriteOptions(),
-              kDatabaseVersionKey,
-              base::Int64ToString(kCurrentDatabaseVersion)));
-}
-
 bool HasInvalidTitle(const std::string& title) {
   return title.empty() ||
       title.find('/') != std::string::npos ||
@@ -1479,11 +1470,7 @@ SyncStatusCode MetadataDatabase::InitializeOnFileTaskRunner() {
       return status;
   }
 
-  if (created) {
-    status = WriteVersionInfo(db_.get());
-    if (status != SYNC_STATUS_OK)
-      return status;
-  } else {
+  if (!created) {
     status = MigrateDatabaseIfNeeded(db_.get());
     if (status != SYNC_STATUS_OK)
       return status;

chrome/browser/sync_file_system/drive_backend/metadata_database_index.cc

@@ -206,6 +206,8 @@ MetadataDatabaseIndex::Create(leveldb::DB* db, leveldb::WriteBatch* batch) {
 
   scoped_ptr<ServiceMetadata> service_metadata = InitializeServiceMetadata(db);
   DatabaseContents contents;
+
+  PutVersionToBatch(kCurrentDatabaseVersion, batch);
   ReadDatabaseContents(db, &contents);
   RemoveUnreachableItems(&contents,
                          service_metadata->sync_root_tracker_id(),

chrome/browser/sync_file_system/drive_backend/metadata_database_index_on_disk.cc

@@ -142,12 +142,16 @@ std::string GenerateDemotedDirtyIDKey(int64 tracker_id) {
 
 }  // namespace
 
-MetadataDatabaseIndexOnDisk::MetadataDatabaseIndexOnDisk(leveldb::DB* db)
-    : db_(db) {
-  // TODO(peria): Add UMA to measure the number of FileMetadata, FileTracker,
-  //    and AppRootId.
-  // TODO(peria): If the DB version is 3, build up index lists.
-  // TODO(peria): Read service metadata from DB.
+// static
+scoped_ptr<MetadataDatabaseIndexOnDisk>
+MetadataDatabaseIndexOnDisk::Create(
+    leveldb::DB* db, leveldb::WriteBatch* batch) {
+  DCHECK(db);
+
+  PutVersionToBatch(kDatabaseOnDiskVersion, batch);
+  scoped_ptr<MetadataDatabaseIndexOnDisk>
+      index(new MetadataDatabaseIndexOnDisk(db));
+  return index.Pass();
 }
 
 MetadataDatabaseIndexOnDisk::~MetadataDatabaseIndexOnDisk() {}
@@ -552,6 +556,14 @@ MetadataDatabaseIndexOnDisk::GetAllMetadataIDs() const {
   return file_ids;
 }
 
+MetadataDatabaseIndexOnDisk::MetadataDatabaseIndexOnDisk(leveldb::DB* db)
+    : db_(db) {
+  // TODO(peria): Add UMA to measure the number of FileMetadata, FileTracker,
+  //    and AppRootId.
+  // TODO(peria): If the DB version is 3, build up index lists.
+  service_metadata_ = InitializeServiceMetadata(db_);
+}
+
 void MetadataDatabaseIndexOnDisk::AddToAppIDIndex(
     const FileTracker& tracker, leveldb::WriteBatch* batch) {
   if (!IsAppRoot(tracker)) {

chrome/browser/sync_file_system/drive_backend/metadata_database_index_on_disk.h

@@ -31,7 +31,9 @@ struct ParentIDAndTitle;
 // Maintains indexes of MetadataDatabase on disk.
 class MetadataDatabaseIndexOnDisk : public MetadataDatabaseIndexInterface {
  public:
-  explicit MetadataDatabaseIndexOnDisk(leveldb::DB* db);
+  static scoped_ptr<MetadataDatabaseIndexOnDisk>
+      Create(leveldb::DB* db, leveldb::WriteBatch* batch);
+
   virtual ~MetadataDatabaseIndexOnDisk();
 
   // MetadataDatabaseIndexInterface overrides.
@@ -84,6 +86,8 @@ class MetadataDatabaseIndexOnDisk : public MetadataDatabaseIndexInterface {
     MULTIPLE,  // Two or more entires are found.
   };
 
+  explicit MetadataDatabaseIndexOnDisk(leveldb::DB* db);
+
   // Maintain indexes from AppIDs to tracker IDs.
   void AddToAppIDIndex(const FileTracker& new_tracker,
                        leveldb::WriteBatch* batch);

chrome/browser/sync_file_system/drive_backend/metadata_database_index_on_disk_unittest.cc

@@ -36,7 +36,7 @@ class MetadataDatabaseIndexOnDiskTest : public testing::Test {
     ASSERT_TRUE(database_dir_.CreateUniqueTempDir());
     in_memory_env_.reset(leveldb::NewMemEnv(leveldb::Env::Default()));
     InitializeLevelDB();
-    index_.reset(new MetadataDatabaseIndexOnDisk(db_.get()));
+    index_ = MetadataDatabaseIndexOnDisk::Create(db_.get(), NULL);
   }
 
   virtual void TearDown() OVERRIDE {