SyncFS: Factor out DriveMetadataDB migration functions

chrome/browser/sync_file_system/drive/metadata_db_migration_util.cc

Index: chrome/browser/sync_file_system/drive/metadata_db_migration_util.cc
diff --git a/chrome/browser/sync_file_system/drive/metadata_db_migration_util.cc b/chrome/browser/sync_file_system/drive/metadata_db_migration_util.cc
index ae395cb15a73a749c278bc3f12c3cc1613ed57d4..3312a2f6767bcdae5a9d5b4ce5d2596ad3eb4f70 100644
--- a/chrome/browser/sync_file_system/drive/metadata_db_migration_util.cc
+++ b/chrome/browser/sync_file_system/drive/metadata_db_migration_util.cc
@@ -9,6 +9,8 @@
 #include "base/string_util.h"
 #include "googleurl/src/gurl.h"
 #include "third_party/leveldatabase/src/include/leveldb/write_batch.h"
+#include "webkit/browser/fileapi/file_system_url.h"
+#include "webkit/common/fileapi/file_system_types.h"
 
 namespace sync_file_system {
 namespace drive {
@@ -24,6 +26,31 @@ std::string RemovePrefix(const std::string& str, const std::string& prefix) {
   return str;
 }
 
+const base::FilePath::CharType kV0FormatPathPrefix[] =
+    FILE_PATH_LITERAL("drive/");
+
+bool ParseV0FormatFileSystemURLString(const GURL& url,

[calvinlo, 2013/05/29 08:36:52]

nit:  possible to add a test for this too? It'll also double as an example of
what the input should look like and output should look like. Just looking at the
function it's hard to tell what goes in and what comes out.

[nhiroki, 2013/05/30 06:15:48]

Done.

+                                      GURL* origin,
+                                      base::FilePath* path) {
+  fileapi::FileSystemType mount_type;
+  base::FilePath virtual_path;
+
+  if (!fileapi::FileSystemURL::ParseFileSystemSchemeURL(
+          url, origin, &mount_type, &virtual_path) ||
+      mount_type != fileapi::kFileSystemTypeExternal) {
+    NOTREACHED() << "Failed to parse filesystem scheme URL";
+    return false;
+  }
+
+  base::FilePath::StringType prefix =
+      base::FilePath(kV0FormatPathPrefix).NormalizePathSeparators().value();
+  if (virtual_path.value().substr(0, prefix.size()) != prefix)
+    return false;
+
+  *path = base::FilePath(virtual_path.value().substr(prefix.size()));
+  return true;
+}
+
 }  // namespace
 
 std::string AddWapiFilePrefix(const std::string& resource_id) {
@@ -68,6 +95,76 @@ std::string RemoveWapiIdPrefix(const std::string& resource_id) {
   return resource_id;
 }
 
+SyncStatusCode MigrateDatabaseFromV0ToV1(leveldb::DB* db) {
+  // Version 0 database format:
+  //   key: "CHANGE_STAMP"
+  //   value: <Largest Changestamp>
+  //
+  //   key: "SYNC_ROOT_DIR"
+  //   value: <Resource ID of the sync root directory>
+  //
+  //   key: "METADATA: " +
+  //        <FileSystemURL serialized by SerializeSyncableFileSystemURL>
+  //   value: <Serialized DriveMetadata>
+  //
+  //   key: "BSYNC_ORIGIN: " + <URL string of a batch sync origin>
+  //   value: <Resource ID of the drive directory for the origin>
+  //
+  //   key: "ISYNC_ORIGIN: " + <URL string of a incremental sync origin>
+  //   value: <Resource ID of the drive directory for the origin>
+  //
+  // Version 1 database format (changed keys/fields are marked with '*'):
+  // * key: "VERSION" (new)
+  // * value: 1
+  //
+  //   key: "CHANGE_STAMP"
+  //   value: <Largest Changestamp>
+  //
+  //   key: "SYNC_ROOT_DIR"
+  //   value: <Resource ID of the sync root directory>
+  //
+  // * key: "METADATA: " + <Origin and URL> (changed)
+  // * value: <Serialized DriveMetadata>
+  //
+  //   key: "BSYNC_ORIGIN: " + <URL string of a batch sync origin>
+  //   value: <Resource ID of the drive directory for the origin>
+  //
+  //   key: "ISYNC_ORIGIN: " + <URL string of a incremental sync origin>
+  //   value: <Resource ID of the drive directory for the origin>
+  //
+  //   key: "DISABLED_ORIGIN: " + <URL string of a disabled origin>
+  //   value: <Resource ID of the drive directory for the origin>
+
+  const char kDatabaseVersionKey[] = "VERSION";
+  const char kDriveMetadataKeyPrefix[] = "METADATA: ";
+  const char kMetadataKeySeparator = ' ';
+
+  leveldb::WriteBatch write_batch;
+  write_batch.Put(kDatabaseVersionKey, "1");
+
+  scoped_ptr<leveldb::Iterator> itr(db->NewIterator(leveldb::ReadOptions()));
+  for (itr->Seek(kDriveMetadataKeyPrefix); itr->Valid(); itr->Next()) {
+    std::string key = itr->key().ToString();
+    if (!StartsWithASCII(key, kDriveMetadataKeyPrefix, true))
+      break;
+    std::string serialized_url(RemovePrefix(key, kDriveMetadataKeyPrefix));
+
+    GURL origin;
+    base::FilePath path;
+    bool success = ParseV0FormatFileSystemURLString(
+        GURL(serialized_url), &origin, &path);
+    DCHECK(success) << serialized_url;
+    std::string new_key = kDriveMetadataKeyPrefix + origin.spec() +
+        kMetadataKeySeparator + path.AsUTF8Unsafe();
+
+    write_batch.Put(new_key, itr->value());
+    write_batch.Delete(key);
+  }
+
+  return LevelDBStatusToSyncStatusCode(
+      db->Write(leveldb::WriteOptions(), &write_batch));
+}
+
 SyncStatusCode MigrateDatabaseFromV1ToV2(leveldb::DB* db) {
   // Strips prefix of WAPI resource ID.
   // (i.e. "file:xxxx" => "xxxx", "folder:yyyy" => "yyyy")