blob: de6be0f64a5aa3ae925e014d4449a326c6fa4231 [file] [log] [blame]
// 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 "sync/engine/process_updates_command.h"
#include <vector>
#include "base/basictypes.h"
#include "base/location.h"
#include "sync/engine/syncer.h"
#include "sync/engine/syncer_proto_util.h"
#include "sync/engine/syncer_util.h"
#include "sync/sessions/sync_session.h"
#include "sync/syncable/directory.h"
#include "sync/syncable/mutable_entry.h"
#include "sync/syncable/syncable_proto_util.h"
#include "sync/syncable/syncable_util.h"
#include "sync/syncable/write_transaction.h"
#include "sync/util/cryptographer.h"
using std::vector;
namespace syncer {
using sessions::SyncSession;
using sessions::StatusController;
using sessions::UpdateProgress;
ProcessUpdatesCommand::ProcessUpdatesCommand() {}
ProcessUpdatesCommand::~ProcessUpdatesCommand() {}
std::set<ModelSafeGroup> ProcessUpdatesCommand::GetGroupsToChange(
const sessions::SyncSession& session) const {
return session.GetEnabledGroupsWithVerifiedUpdates();
SyncerError ProcessUpdatesCommand::ModelChangingExecuteImpl(
SyncSession* session) {
syncable::Directory* dir = session->context()->directory();
const sessions::UpdateProgress* progress =
if (!progress)
return SYNCER_OK; // Nothing to do.
syncable::WriteTransaction trans(FROM_HERE, syncable::SYNCER, dir);
vector<sessions::VerifiedUpdate>::const_iterator it;
for (it = progress->VerifiedUpdatesBegin();
it != progress->VerifiedUpdatesEnd();
++it) {
const sync_pb::SyncEntity& update = it->second;
if (it->first != VERIFY_SUCCESS && it->first != VERIFY_UNDELETE)
switch (ProcessUpdate(update,
&trans)) {
StatusController* status = session->mutable_status_controller();
return SYNCER_OK;
namespace {
// Returns true if the entry is still ok to process.
bool ReverifyEntry(syncable::WriteTransaction* trans,
const sync_pb::SyncEntity& entry,
syncable::MutableEntry* same_id) {
const bool deleted = entry.has_deleted() && entry.deleted();
const bool is_directory = IsFolder(entry);
const ModelType model_type = GetModelType(entry);
return VERIFY_SUCCESS == VerifyUpdateConsistency(trans,
} // namespace
// Process a single update. Will avoid touching global state.
ServerUpdateProcessingResult ProcessUpdatesCommand::ProcessUpdate(
const sync_pb::SyncEntity& update,
const Cryptographer* cryptographer,
syncable::WriteTransaction* const trans) {
const syncable::Id& server_id = SyncableIdFromProto(update.id_string());
const std::string name = SyncerProtoUtil::NameFromSyncEntity(update);
// Look to see if there's a local item that should recieve this update,
// maybe due to a duplicate client tag or a lost commit response.
syncable::Id local_id = FindLocalIdToUpdate(trans, update);
// FindLocalEntryToUpdate has veto power.
if (local_id.IsNull()) {
return SUCCESS_PROCESSED; // The entry has become irrelevant.
CreateNewEntry(trans, local_id);
// We take a two step approach. First we store the entries data in the
// server fields of a local entry and then move the data to the local fields
syncable::MutableEntry target_entry(trans, syncable::GET_BY_ID, local_id);
// We need to run the Verify checks again; the world could have changed
// since VerifyUpdatesCommand.
if (!ReverifyEntry(trans, update, &target_entry)) {
return SUCCESS_PROCESSED; // The entry has become irrelevant.
// If we're repurposing an existing local entry with a new server ID,
// change the ID now, after we're sure that the update can succeed.
if (local_id != server_id) {
ChangeEntryIDAndUpdateChildren(trans, &target_entry, server_id);
// When IDs change, versions become irrelevant. Forcing BASE_VERSION
// to zero would ensure that this update gets applied, but would indicate
// creation or undeletion if it were committed that way. Instead, prefer
// forcing BASE_VERSION to entry.version() while also forcing
// IS_UNAPPLIED_UPDATE to true. If the item is UNSYNCED, it's committable
// from the new state; it may commit before the conflict resolver gets
// a crack at it.
if (target_entry.Get(syncable::IS_UNSYNCED) ||
target_entry.Get(syncable::BASE_VERSION) > 0) {
// If either of these conditions are met, then we can expect valid client
// fields for this entry. When BASE_VERSION is positive, consistency is
// enforced on the client fields at update-application time. Otherwise,
// we leave the BASE_VERSION field alone; it'll get updated the first time
// we successfully apply this update.
target_entry.Put(syncable::BASE_VERSION, update.version());
// Force application of this update, no matter what.
target_entry.Put(syncable::IS_UNAPPLIED_UPDATE, true);
// If this is a newly received undecryptable update, and the only thing that
// has changed are the specifics, store the original decryptable specifics,
// (on which any current or future local changes are based) before we
// overwrite SERVER_SPECIFICS.
// MTIME, CTIME, and NON_UNIQUE_NAME are not enforced.
if (!update.deleted() && !target_entry.Get(syncable::SERVER_IS_DEL) &&
(SyncableIdFromProto(update.parent_id_string()) ==
target_entry.Get(syncable::SERVER_PARENT_ID)) &&
(update.position_in_parent() ==
target_entry.Get(syncable::SERVER_POSITION_IN_PARENT)) &&
update.has_specifics() && update.specifics().has_encrypted() &&
!cryptographer->CanDecrypt(update.specifics().encrypted())) {
sync_pb::EntitySpecifics prev_specifics =
// We only store the old specifics if they were decryptable and applied and
// there is no BASE_SERVER_SPECIFICS already. Else do nothing.
if (!target_entry.Get(syncable::IS_UNAPPLIED_UPDATE) &&
target_entry.Get(syncable::BASE_SERVER_SPECIFICS))) &&
(!prev_specifics.has_encrypted() ||
cryptographer->CanDecrypt(prev_specifics.encrypted()))) {
DVLOG(2) << "Storing previous server specifcs: "
<< prev_specifics.SerializeAsString();
target_entry.Put(syncable::BASE_SERVER_SPECIFICS, prev_specifics);
} else if (IsRealDataType(GetModelTypeFromSpecifics(
target_entry.Get(syncable::BASE_SERVER_SPECIFICS)))) {
// We have a BASE_SERVER_SPECIFICS, but a subsequent non-specifics-only
// change arrived. As a result, we can't use the specifics alone to detect
// changes, so we clear BASE_SERVER_SPECIFICS.
UpdateServerFieldsFromUpdate(&target_entry, update, name);
} // namespace syncer