Split out gdata_directory_service*

chrome/browser/chromeos/gdata/gdata_directory_service.cc

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/chromeos/gdata/gdata_directory_service.h"
+
+#include <leveldb/db.h>
+
+#include "base/message_loop_proxy.h"
+#include "base/platform_file.h"
+#include "base/string_number_conversions.h"
+#include "base/string_util.h"
+#include "base/stringprintf.h"
+#include "base/sequenced_task_runner.h"
+#include "base/tracked_objects.h"
+#include "base/utf_string_conversions.h"
+#include "chrome/browser/chromeos/gdata/gdata.pb.h"
+#include "chrome/browser/chromeos/gdata/gdata_util.h"
+#include "chrome/browser/chromeos/gdata/gdata_wapi_parser.h"
+#include "content/public/browser/browser_thread.h"
+#include "net/base/escape.h"
+
+using content::BrowserThread;
+
+namespace gdata {
+namespace {
+
+// m: prefix for filesystem metadata db keys, version and largest_changestamp.
+// r: prefix for resource id db keys.
+const char kDBKeyLargestChangestamp[] = "m:largest_changestamp";
+const char kDBKeyVersion[] = "m:version";
+const char kDBKeyResourceIdPrefix[] = "r:";
+
+// Returns true if |proto| is a valid proto as the root directory.
+// Used to reject incompatible proto.
+bool IsValidRootDirectoryProto(const GDataDirectoryProto& proto) {
+  const GDataEntryProto& entry_proto = proto.gdata_entry();
+  // The title field for the root directory was originally empty, then
+  // changed to "gdata", then changed to "drive". Discard the proto data if
+  // the older formats are detected. See crbug.com/128133 for details.
+  if (entry_proto.title() != "drive") {
+    LOG(ERROR) << "Incompatible proto detected (bad title): "
+               << entry_proto.title();
+    return false;
+  }
+  // The title field for the root directory was originally empty. Discard
+  // the proto data if the older format is detected.
+  if (entry_proto.resource_id() != kGDataRootDirectoryResourceId) {
+    LOG(ERROR) << "Incompatible proto detected (bad resource ID): "
+               << entry_proto.resource_id();
+    return false;
+  }
+
+  return true;
+}
+
+}  // namespace
+
+EntryInfoResult::EntryInfoResult() : error(GDATA_FILE_ERROR_FAILED) {
+}
+
+EntryInfoResult::~EntryInfoResult() {
+}
+
+EntryInfoPairResult::EntryInfoPairResult() {
+}
+
+EntryInfoPairResult::~EntryInfoPairResult() {
+}
+
+// ResourceMetadataDB implementation.
+
+// Params for GDatadirectoryServiceDB::Create.
+struct CreateDBParams {
+  CreateDBParams(const FilePath& db_path,
+                 base::SequencedTaskRunner* blocking_task_runner)
+                 : db_path(db_path),
+                   blocking_task_runner(blocking_task_runner) {
+  }
+
+  FilePath db_path;
+  scoped_refptr<base::SequencedTaskRunner> blocking_task_runner;
+  scoped_ptr<ResourceMetadataDB> db;
+  GDataDirectoryService::SerializedMap serialized_resources;
+};
+
+// Wrapper for level db. All methods must be called on blocking thread.
+class ResourceMetadataDB {
+ public:
+  ResourceMetadataDB(const FilePath& db_path,
+                          base::SequencedTaskRunner* blocking_task_runner);
+
+  // Initializes the database.
+  void Init();
+
+  // Reads the database into |serialized_resources|.
+  void Read(GDataDirectoryService::SerializedMap* serialized_resources);
+
+  // Saves |serialized_resources| to the database.
+  void Save(const GDataDirectoryService::SerializedMap& serialized_resources);
+
+ private:
+  // Clears the database.
+  void Clear();
+
+  scoped_refptr<base::SequencedTaskRunner> blocking_task_runner_;
+  scoped_ptr<leveldb::DB> level_db_;
+  FilePath db_path_;
+};
+
+ResourceMetadataDB::ResourceMetadataDB(const FilePath& db_path,
+    base::SequencedTaskRunner* blocking_task_runner)
+  : blocking_task_runner_(blocking_task_runner),
+    db_path_(db_path) {
+  DCHECK(blocking_task_runner_->RunsTasksOnCurrentThread());
+}
+
+// Creates, initializes and reads from the database.
+// This must be defined after ResourceMetadataDB and CreateDBParams.
+static void CreateResourceMetadataDBOnBlockingPool(
+    CreateDBParams* params) {
+  DCHECK(params->blocking_task_runner->RunsTasksOnCurrentThread());
+  DCHECK(!params->db_path.empty());
+
+  params->db.reset(new ResourceMetadataDB(params->db_path,
+                                               params->blocking_task_runner));
+  params->db->Init();
+  params->db->Read(&params->serialized_resources);
+}
+
+void ResourceMetadataDB::Init() {
+  DCHECK(blocking_task_runner_->RunsTasksOnCurrentThread());
+  DCHECK(!db_path_.empty());
+
+  DVLOG(1) << "Init " << db_path_.value();
+
+  leveldb::DB* level_db = NULL;
+  leveldb::Options options;
+  options.create_if_missing = true;
+  leveldb::Status db_status = leveldb::DB::Open(options, db_path_.value(),
+                                                &level_db);
+  DCHECK(level_db);
+  DCHECK(db_status.ok());
+  level_db_.reset(level_db);
+}
+
+void ResourceMetadataDB::Read(
+  GDataDirectoryService::SerializedMap* serialized_resources) {
+  DCHECK(blocking_task_runner_->RunsTasksOnCurrentThread());
+  DCHECK(serialized_resources);
+  DVLOG(1) << "Read " << db_path_.value();
+
+  scoped_ptr<leveldb::Iterator> iter(level_db_->NewIterator(
+        leveldb::ReadOptions()));
+  for (iter->SeekToFirst(); iter->Valid(); iter->Next()) {
+    DVLOG(1) << "Read, resource " << iter->key().ToString();
+    serialized_resources->insert(std::make_pair(iter->key().ToString(),
+                                                iter->value().ToString()));
+  }
+}
+
+void ResourceMetadataDB::Save(
+    const GDataDirectoryService::SerializedMap& serialized_resources) {
+  DCHECK(blocking_task_runner_->RunsTasksOnCurrentThread());
+
+  Clear();
+  for (GDataDirectoryService::SerializedMap::const_iterator iter =
+      serialized_resources.begin();
+      iter != serialized_resources.end(); ++iter) {
+    DVLOG(1) << "Saving resource " << iter->first << " to db";
+    leveldb::Status status = level_db_->Put(leveldb::WriteOptions(),
+                                            leveldb::Slice(iter->first),
+                                            leveldb::Slice(iter->second));
+    if (!status.ok()) {
+      LOG(ERROR) << "leveldb Put failed of " << iter->first
+                 << ", with " << status.ToString();
+      NOTREACHED();
+    }
+  }
+}
+
+void ResourceMetadataDB::Clear() {
+  level_db_.reset();
+  leveldb::DestroyDB(db_path_.value(), leveldb::Options());
+  Init();
+}
+
+// GDataDirectoryService class implementation.
+
+GDataDirectoryService::GDataDirectoryService()
+    : blocking_task_runner_(NULL),
+      serialized_size_(0),
+      largest_changestamp_(0),
+      origin_(UNINITIALIZED),
+      weak_ptr_factory_(ALLOW_THIS_IN_INITIALIZER_LIST(this)) {
+  root_.reset(CreateGDataDirectory());
+  if (!util::IsDriveV2ApiEnabled())
+    InitializeRootEntry(kGDataRootDirectoryResourceId);
+}
+
+GDataDirectoryService::~GDataDirectoryService() {
+  ClearRoot();
+
+  // Ensure db is closed on the blocking pool.
+  if (blocking_task_runner_ && directory_service_db_.get())
+    blocking_task_runner_->DeleteSoon(FROM_HERE,
+                                      directory_service_db_.release());
+}
+
+GDataEntry* GDataDirectoryService::FromDocumentEntry(DocumentEntry* doc) {
+  DCHECK(doc);
+  GDataEntry* entry = NULL;
+  if (doc->is_folder())
+    entry = CreateGDataDirectory();
+  else if (doc->is_hosted_document() || doc->is_file())
+    entry = CreateGDataFile();
+
+  if (entry)
+    entry->InitFromDocumentEntry(doc);
+  return entry;
+}
+
+GDataFile* GDataDirectoryService::CreateGDataFile() {
+  return new GDataFile(this);
+}
+
+GDataDirectory* GDataDirectoryService::CreateGDataDirectory() {
+  return new GDataDirectory(this);
+}
+
+void GDataDirectoryService::InitializeRootEntry(const std::string& root_id) {
+  root_.reset(CreateGDataDirectory());
+  root_->set_title(kGDataRootDirectory);
+  root_->SetBaseNameFromTitle();
+  root_->set_resource_id(root_id);
+  AddEntryToResourceMap(root_.get());
+}
+
+void GDataDirectoryService::ClearRoot() {
+  // Note that children have a reference to root_,
+  // so we need to delete them here.
+  root_->RemoveChildren();
+  RemoveEntryFromResourceMap(root_.get());
+  DCHECK(resource_map_.empty());
+  resource_map_.clear();
+  root_.reset();
+}
+
+void GDataDirectoryService::AddEntryToDirectory(
+    GDataDirectory* directory,
+    GDataEntry* new_entry,
+    const FileMoveCallback& callback) {
+  DCHECK(directory);
+  DCHECK(new_entry);
+  DCHECK(!callback.is_null());
+
+  directory->AddEntry(new_entry);
+  DVLOG(1) << "AddEntryToDirectory " << new_entry->GetFilePath().value();
+  base::MessageLoopProxy::current()->PostTask(FROM_HERE,
+      base::Bind(callback, GDATA_FILE_OK, new_entry->GetFilePath()));
+}
+
+void GDataDirectoryService::MoveEntryToDirectory(
+    const FilePath& directory_path,
+    GDataEntry* entry,
+    const FileMoveCallback& callback) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK(entry);
+  DCHECK(!callback.is_null());
+
+  if (entry->parent())
+    entry->parent()->RemoveChild(entry);
+
+  GDataEntry* destination = FindEntryByPathSync(directory_path);
+  FilePath moved_file_path;
+  GDataFileError error = GDATA_FILE_ERROR_FAILED;
+  if (!destination) {
+    error = GDATA_FILE_ERROR_NOT_FOUND;
+  } else if (!destination->AsGDataDirectory()) {
+    error = GDATA_FILE_ERROR_NOT_A_DIRECTORY;
+  } else {
+    destination->AsGDataDirectory()->AddEntry(entry);
+    moved_file_path = entry->GetFilePath();
+    error = GDATA_FILE_OK;
+  }
+  DVLOG(1) << "MoveEntryToDirectory " << moved_file_path.value();
+  base::MessageLoopProxy::current()->PostTask(
+      FROM_HERE, base::Bind(callback, error, moved_file_path));
+}
+
+void GDataDirectoryService::RemoveEntryFromParent(
+    GDataEntry* entry,
+    const FileMoveCallback& callback) {
+  GDataDirectory* parent = entry->parent();
+  DCHECK(parent);
+  DCHECK(!callback.is_null());
+  DVLOG(1) << "RemoveEntryFromParent " << entry->GetFilePath().value();
+
+  parent->RemoveEntry(entry);
+  base::MessageLoopProxy::current()->PostTask(FROM_HERE,
+      base::Bind(callback, GDATA_FILE_OK, parent->GetFilePath()));
+}
+
+void GDataDirectoryService::AddEntryToResourceMap(GDataEntry* entry) {
+  // GDataFileSystem has already locked.
+  DVLOG(1) << "AddEntryToResourceMap " << entry->resource_id();
+  resource_map_.insert(std::make_pair(entry->resource_id(), entry));
+}
+
+void GDataDirectoryService::RemoveEntryFromResourceMap(GDataEntry* entry) {
+  // GDataFileSystem has already locked.
+  resource_map_.erase(entry->resource_id());
+}
+
+GDataEntry* GDataDirectoryService::FindEntryByPathSync(
+    const FilePath& file_path) {
+  if (file_path == root_->GetFilePath())
+    return root_.get();
+
+  std::vector<FilePath::StringType> components;
+  file_path.GetComponents(&components);
+  GDataDirectory* current_dir = root_.get();
+
+  for (size_t i = 1; i < components.size() && current_dir; ++i) {
+    GDataEntry* entry = current_dir->FindChild(components[i]);
+    if (!entry)
+      return NULL;
+
+    if (i == components.size() - 1)  // Last component.
+      return entry;
+    else
+      current_dir = entry->AsGDataDirectory();
+  }
+  return NULL;
+}
+
+void GDataDirectoryService::FindEntryByPathAndRunSync(
+    const FilePath& search_file_path,
+    const FindEntryCallback& callback) {
+  GDataEntry* entry = FindEntryByPathSync(search_file_path);
+  callback.Run(entry ? GDATA_FILE_OK : GDATA_FILE_ERROR_NOT_FOUND, entry);
+}
+
+GDataEntry* GDataDirectoryService::GetEntryByResourceId(
+    const std::string& resource) {
+  // GDataFileSystem has already locked.
+  ResourceMap::const_iterator iter = resource_map_.find(resource);
+  return iter == resource_map_.end() ? NULL : iter->second;
+}
+
+void GDataDirectoryService::GetEntryByResourceIdAsync(
+    const std::string& resource_id,
+    const GetEntryByResourceIdCallback& callback) {
+  GDataEntry* entry = GetEntryByResourceId(resource_id);
+  callback.Run(entry);
+}
+
+void GDataDirectoryService::GetEntryInfoByPath(
+    const FilePath& path,
+    const GetEntryInfoCallback& callback) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK(!callback.is_null());
+
+  scoped_ptr<GDataEntryProto> entry_proto;
+  GDataFileError error = GDATA_FILE_ERROR_FAILED;
+
+  GDataEntry* entry = FindEntryByPathSync(path);
+  if (entry) {
+    entry_proto.reset(new GDataEntryProto);
+    entry->ToProtoFull(entry_proto.get());
+    error = GDATA_FILE_OK;
+  } else {
+    error = GDATA_FILE_ERROR_NOT_FOUND;
+  }
+
+  base::MessageLoopProxy::current()->PostTask(
+      FROM_HERE,
+      base::Bind(callback, error, base::Passed(&entry_proto)));
+}
+
+void GDataDirectoryService::ReadDirectoryByPath(
+    const FilePath& path,
+    const ReadDirectoryCallback& callback) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK(!callback.is_null());
+
+  scoped_ptr<GDataEntryProtoVector> entries;
+  GDataFileError error = GDATA_FILE_ERROR_FAILED;
+
+  GDataEntry* entry = FindEntryByPathSync(path);
+  if (entry && entry->AsGDataDirectory()) {
+    entries = entry->AsGDataDirectory()->ToProtoVector();
+    error = GDATA_FILE_OK;
+  } else if (entry && !entry->AsGDataDirectory()) {
+    error = GDATA_FILE_ERROR_NOT_A_DIRECTORY;
+  } else {
+    error = GDATA_FILE_ERROR_NOT_FOUND;
+  }
+
+  base::MessageLoopProxy::current()->PostTask(
+      FROM_HERE,
+      base::Bind(callback, error, base::Passed(&entries)));
+}
+
+void GDataDirectoryService::GetEntryInfoPairByPaths(
+    const FilePath& first_path,
+    const FilePath& second_path,
+    const GetEntryInfoPairCallback& callback) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK(!callback.is_null());
+
+  // Get the first entry.
+  GetEntryInfoByPath(
+      first_path,
+      base::Bind(&GDataDirectoryService::GetEntryInfoPairByPathsAfterGetFirst,
+                 weak_ptr_factory_.GetWeakPtr(),
+                 first_path,
+                 second_path,
+                 callback));
+}
+
+void GDataDirectoryService::RefreshFile(scoped_ptr<GDataFile> fresh_file) {
+  DCHECK(fresh_file.get());
+
+  // Need to get a reference here because Passed() could get evaluated first.
+  const std::string& resource_id = fresh_file->resource_id();
+  GetEntryByResourceIdAsync(
+      resource_id,
+      base::Bind(&GDataDirectoryService::RefreshFileInternal,
+                 base::Passed(&fresh_file)));
+}
+
+// static
+void GDataDirectoryService::RefreshFileInternal(
+    scoped_ptr<GDataFile> fresh_file,
+    GDataEntry* old_entry) {
+  GDataDirectory* entry_parent = old_entry ? old_entry->parent() : NULL;
+  if (entry_parent) {
+    DCHECK_EQ(fresh_file->resource_id(), old_entry->resource_id());
+    DCHECK(old_entry->AsGDataFile());
+
+    entry_parent->RemoveEntry(old_entry);
+    entry_parent->AddEntry(fresh_file.release());
+  }
+}
+
+void GDataDirectoryService::RefreshDirectory(
+    const std::string& directory_resource_id,
+    const ResourceMap& file_map,
+    const FileMoveCallback& callback) {
+  DCHECK(!callback.is_null());
+  GetEntryByResourceIdAsync(
+      directory_resource_id,
+      base::Bind(&GDataDirectoryService::RefreshDirectoryInternal,
+                 file_map,
+                 callback));
+}
+
+// static
+void GDataDirectoryService::RefreshDirectoryInternal(
+    const ResourceMap& file_map,
+    const FileMoveCallback& callback,
+    GDataEntry* directory_entry) {
+  DCHECK(!callback.is_null());
+
+  if (!directory_entry) {
+    callback.Run(GDATA_FILE_ERROR_NOT_FOUND, FilePath());
+    return;
+  }
+
+  GDataDirectory* directory = directory_entry->AsGDataDirectory();
+  if (!directory) {
+    callback.Run(GDATA_FILE_ERROR_NOT_A_DIRECTORY, FilePath());
+    return;
+  }
+
+  directory->RemoveChildFiles();
+  // Add files from file_map.
+  for (ResourceMap::const_iterator it = file_map.begin();
+       it != file_map.end(); ++it) {
+    scoped_ptr<GDataEntry> entry(it->second);
+    // Skip if it's not a file (i.e. directory).
+    if (!entry->AsGDataFile())
+      continue;
+    directory->AddEntry(entry.release());
+  }
+
+  callback.Run(GDATA_FILE_OK, directory->GetFilePath());
+}
+
+void GDataDirectoryService::InitFromDB(
+    const FilePath& db_path,
+    base::SequencedTaskRunner* blocking_task_runner,
+    const FileOperationCallback& callback) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK(!db_path.empty());
+  DCHECK(blocking_task_runner);
+
+  if (directory_service_db_.get()) {
+    if (!callback.is_null())
+      callback.Run(GDATA_FILE_ERROR_FAILED);
+    return;
+  }
+
+  blocking_task_runner_ = blocking_task_runner;
+
+  DVLOG(1) << "InitFromDB " << db_path.value();
+
+  CreateDBParams* create_params =
+      new CreateDBParams(db_path, blocking_task_runner);
+  blocking_task_runner_->PostTaskAndReply(
+      FROM_HERE,
+      base::Bind(&CreateResourceMetadataDBOnBlockingPool,
+                 create_params),
+      base::Bind(&GDataDirectoryService::InitResourceMap,
+                 weak_ptr_factory_.GetWeakPtr(),
+                 base::Owned(create_params),
+                 callback));
+}
+
+void GDataDirectoryService::InitResourceMap(
+    CreateDBParams* create_params,
+    const FileOperationCallback& callback) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK(create_params);
+  DCHECK(!directory_service_db_.get());
+
+  SerializedMap* serialized_resources = &create_params->serialized_resources;
+  directory_service_db_ = create_params->db.Pass();
+  if (serialized_resources->empty()) {
+    origin_ = INITIALIZING;
+    if (!callback.is_null())
+      callback.Run(GDATA_FILE_ERROR_NOT_FOUND);
+    return;
+  }
+
+  ClearRoot();
+
+  // Version check.
+  int32 version = 0;
+  SerializedMap::iterator iter = serialized_resources->find(kDBKeyVersion);
+  if (iter == serialized_resources->end() ||
+      !base::StringToInt(iter->second, &version) ||
+      version != kProtoVersion) {
+    if (!callback.is_null())
+      callback.Run(GDATA_FILE_ERROR_FAILED);
+    return;
+  }
+  serialized_resources->erase(iter);
+
+  // Get the largest changestamp.
+  iter = serialized_resources->find(kDBKeyLargestChangestamp);
+  if (iter == serialized_resources->end() ||
+      !base::StringToInt64(iter->second, &largest_changestamp_)) {
+    NOTREACHED() << "Could not find/parse largest_changestamp";
+    if (!callback.is_null())
+      callback.Run(GDATA_FILE_ERROR_FAILED);
+    return;
+  } else {
+    DVLOG(1) << "InitResourceMap largest_changestamp_" << largest_changestamp_;
+    serialized_resources->erase(iter);
+  }
+
+  ResourceMap resource_map;
+  for (SerializedMap::const_iterator iter = serialized_resources->begin();
+      iter != serialized_resources->end(); ++iter) {
+    if (iter->first.find(kDBKeyResourceIdPrefix) != 0) {
+      NOTREACHED() << "Incorrect prefix for db key " << iter->first;
+      continue;
+    }
+
+    const std::string resource_id =
+        iter->first.substr(strlen(kDBKeyResourceIdPrefix));
+    scoped_ptr<GDataEntry> entry = FromProtoString(iter->second);
+    if (entry.get()) {
+      DVLOG(1) << "Inserting resource " << resource_id
+               << " into resource_map";
+      resource_map.insert(std::make_pair(resource_id, entry.release()));
+    } else {
+      NOTREACHED() << "Failed to parse GDataEntry for resource " << resource_id;
+    }
+  }
+
+  // Fix up parent-child relations.
+  for (ResourceMap::iterator iter = resource_map.begin();
+      iter != resource_map.end(); ++iter) {
+    GDataEntry* entry = iter->second;
+    ResourceMap::iterator parent_it =
+        resource_map.find(entry->parent_resource_id());
+    if (parent_it != resource_map.end()) {
+      GDataDirectory* parent = parent_it->second->AsGDataDirectory();
+      if (parent) {
+        DVLOG(1) << "Adding " << entry->resource_id()
+                 << " as a child of " << parent->resource_id();
+        parent->AddEntry(entry);
+      } else {
+        NOTREACHED() << "Parent is not a directory " << parent->resource_id();
+      }
+    } else if (entry->resource_id() == kGDataRootDirectoryResourceId) {
+      root_.reset(entry->AsGDataDirectory());
+      DCHECK(root_.get());
+      AddEntryToResourceMap(root_.get());
+    } else {
+      NOTREACHED() << "Missing parent id " << entry->parent_resource_id()
+                   << " for resource " << entry->resource_id();
+    }
+  }
+
+  DCHECK(root_.get());
+  DCHECK_EQ(resource_map.size(), resource_map_.size());
+  DCHECK_EQ(resource_map.size(), serialized_resources->size());
+
+  origin_ = FROM_CACHE;
+
+  if (!callback.is_null())
+    callback.Run(GDATA_FILE_OK);
+}
+
+void GDataDirectoryService::SaveToDB() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+  if (!blocking_task_runner_ || !directory_service_db_.get()) {
+    NOTREACHED();
+    return;
+  }
+
+  size_t serialized_size = 0;
+  SerializedMap serialized_resources;
+  for (ResourceMap::const_iterator iter = resource_map_.begin();
+      iter != resource_map_.end(); ++iter) {
+    GDataEntryProto proto;
+    iter->second->ToProtoFull(&proto);
+    std::string serialized_string;
+    const bool ok = proto.SerializeToString(&serialized_string);
+    DCHECK(ok);
+    if (ok) {
+      serialized_resources.insert(
+          std::make_pair(std::string(kDBKeyResourceIdPrefix) + iter->first,
+                         serialized_string));
+      serialized_size += serialized_string.size();
+    }
+  }
+
+  serialized_resources.insert(std::make_pair(kDBKeyVersion,
+      base::IntToString(kProtoVersion)));
+  serialized_resources.insert(std::make_pair(kDBKeyLargestChangestamp,
+      base::IntToString(largest_changestamp_)));
+  set_last_serialized(base::Time::Now());
+  set_serialized_size(serialized_size);
+
+  blocking_task_runner_->PostTask(
+      FROM_HERE,
+      base::Bind(&ResourceMetadataDB::Save,
+                 base::Unretained(directory_service_db_.get()),
+                 serialized_resources));
+}
+
+void GDataDirectoryService::SerializeToString(
+    std::string* serialized_proto) const {
+  GDataRootDirectoryProto proto;
+  root_->ToProto(proto.mutable_gdata_directory());
+  proto.set_largest_changestamp(largest_changestamp_);
+  proto.set_version(kProtoVersion);
+
+  const bool ok = proto.SerializeToString(serialized_proto);
+  DCHECK(ok);
+}
+
+bool GDataDirectoryService::ParseFromString(
+    const std::string& serialized_proto) {
+  GDataRootDirectoryProto proto;
+  if (!proto.ParseFromString(serialized_proto))
+    return false;
+
+  if (proto.version() != kProtoVersion) {
+    LOG(ERROR) << "Incompatible proto detected (incompatible version): "
+               << proto.version();
+    return false;
+  }
+
+  if (!IsValidRootDirectoryProto(proto.gdata_directory()))
+    return false;
+
+  if (!root_->FromProto(proto.gdata_directory()))
+    return false;
+
+  origin_ = FROM_CACHE;
+  largest_changestamp_ = proto.largest_changestamp();
+
+  return true;
+}
+
+scoped_ptr<GDataEntry> GDataDirectoryService::FromProtoString(
+    const std::string& serialized_proto) {
+  GDataEntryProto entry_proto;
+  if (!entry_proto.ParseFromString(serialized_proto))
+    return scoped_ptr<GDataEntry>();
+
+  scoped_ptr<GDataEntry> entry;
+  if (entry_proto.file_info().is_directory()) {
+    entry.reset(CreateGDataDirectory());
+    // Call GDataEntry::FromProto instead of GDataDirectory::FromProto because
+    // the proto does not include children.
+    if (!entry->FromProto(entry_proto)) {
+      NOTREACHED() << "FromProto (directory) failed";
+      entry.reset();
+    }
+  } else {
+    scoped_ptr<GDataFile> file(CreateGDataFile());
+    // Call GDataFile::FromProto.
+    if (file->FromProto(entry_proto)) {
+      entry.reset(file.release());
+    } else {
+      NOTREACHED() << "FromProto (file) failed";
+    }
+  }
+  return entry.Pass();
+}
+
+void GDataDirectoryService::GetEntryInfoPairByPathsAfterGetFirst(
+    const FilePath& first_path,
+    const FilePath& second_path,
+    const GetEntryInfoPairCallback& callback,
+    GDataFileError error,
+    scoped_ptr<GDataEntryProto> entry_proto) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK(!callback.is_null());
+
+  scoped_ptr<EntryInfoPairResult> result(new EntryInfoPairResult);
+  result->first.path = first_path;
+  result->first.error = error;
+  result->first.proto = entry_proto.Pass();
+
+  // If the first one is not found, don't continue.
+  if (error != GDATA_FILE_OK) {
+    callback.Run(result.Pass());
+    return;
+  }
+
+  // Get the second entry.
+  GetEntryInfoByPath(
+      second_path,
+      base::Bind(&GDataDirectoryService::GetEntryInfoPairByPathsAfterGetSecond,
+                 weak_ptr_factory_.GetWeakPtr(),
+                 second_path,
+                 callback,
+                 base::Passed(&result)));
+}
+
+void GDataDirectoryService::GetEntryInfoPairByPathsAfterGetSecond(
+    const FilePath& second_path,
+    const GetEntryInfoPairCallback& callback,
+    scoped_ptr<EntryInfoPairResult> result,
+    GDataFileError error,
+    scoped_ptr<GDataEntryProto> entry_proto) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK(!callback.is_null());
+  DCHECK(result.get());
+
+  result->second.path = second_path;
+  result->second.error = error;
+  result->second.proto = entry_proto.Pass();
+
+  callback.Run(result.Pass());
+}
+
+}  // namespace gdata