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      1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "sync/engine/syncer_proto_util.h"
      6 
      7 #include "base/format_macros.h"
      8 #include "base/strings/stringprintf.h"
      9 #include "google_apis/google_api_keys.h"
     10 #include "sync/engine/net/server_connection_manager.h"
     11 #include "sync/engine/syncer.h"
     12 #include "sync/engine/syncer_types.h"
     13 #include "sync/engine/traffic_logger.h"
     14 #include "sync/internal_api/public/base/model_type.h"
     15 #include "sync/protocol/sync_enums.pb.h"
     16 #include "sync/protocol/sync_protocol_error.h"
     17 #include "sync/sessions/sync_session.h"
     18 #include "sync/syncable/directory.h"
     19 #include "sync/syncable/entry.h"
     20 #include "sync/syncable/syncable-inl.h"
     21 #include "sync/syncable/syncable_proto_util.h"
     22 #include "sync/util/time.h"
     23 
     24 using std::string;
     25 using std::stringstream;
     26 using sync_pb::ClientToServerMessage;
     27 using sync_pb::ClientToServerResponse;
     28 
     29 namespace syncer {
     30 
     31 using sessions::SyncSession;
     32 using syncable::BASE_VERSION;
     33 using syncable::CTIME;
     34 using syncable::ID;
     35 using syncable::IS_DEL;
     36 using syncable::IS_DIR;
     37 using syncable::IS_UNSYNCED;
     38 using syncable::MTIME;
     39 using syncable::PARENT_ID;
     40 
     41 namespace {
     42 
     43 // Time to backoff syncing after receiving a throttled response.
     44 const int kSyncDelayAfterThrottled = 2 * 60 * 60;  // 2 hours
     45 
     46 void LogResponseProfilingData(const ClientToServerResponse& response) {
     47   if (response.has_profiling_data()) {
     48     stringstream response_trace;
     49     response_trace << "Server response trace:";
     50 
     51     if (response.profiling_data().has_user_lookup_time()) {
     52       response_trace << " user lookup: "
     53                      << response.profiling_data().user_lookup_time() << "ms";
     54     }
     55 
     56     if (response.profiling_data().has_meta_data_write_time()) {
     57       response_trace << " meta write: "
     58                      << response.profiling_data().meta_data_write_time()
     59                      << "ms";
     60     }
     61 
     62     if (response.profiling_data().has_meta_data_read_time()) {
     63       response_trace << " meta read: "
     64                      << response.profiling_data().meta_data_read_time() << "ms";
     65     }
     66 
     67     if (response.profiling_data().has_file_data_write_time()) {
     68       response_trace << " file write: "
     69                      << response.profiling_data().file_data_write_time()
     70                      << "ms";
     71     }
     72 
     73     if (response.profiling_data().has_file_data_read_time()) {
     74       response_trace << " file read: "
     75                      << response.profiling_data().file_data_read_time() << "ms";
     76     }
     77 
     78     if (response.profiling_data().has_total_request_time()) {
     79       response_trace << " total time: "
     80                      << response.profiling_data().total_request_time() << "ms";
     81     }
     82     DVLOG(1) << response_trace.str();
     83   }
     84 }
     85 
     86 SyncerError ServerConnectionErrorAsSyncerError(
     87     const HttpResponse::ServerConnectionCode server_status) {
     88   switch (server_status) {
     89     case HttpResponse::CONNECTION_UNAVAILABLE:
     90       return NETWORK_CONNECTION_UNAVAILABLE;
     91     case HttpResponse::IO_ERROR:
     92       return NETWORK_IO_ERROR;
     93     case HttpResponse::SYNC_SERVER_ERROR:
     94       // FIXME what does this mean?
     95       return SYNC_SERVER_ERROR;
     96     case HttpResponse::SYNC_AUTH_ERROR:
     97       return SYNC_AUTH_ERROR;
     98     case HttpResponse::RETRY:
     99       return SERVER_RETURN_TRANSIENT_ERROR;
    100     case HttpResponse::SERVER_CONNECTION_OK:
    101     case HttpResponse::NONE:
    102     default:
    103       NOTREACHED();
    104       return UNSET;
    105   }
    106 }
    107 
    108 SyncProtocolErrorType ConvertSyncProtocolErrorTypePBToLocalType(
    109     const sync_pb::SyncEnums::ErrorType& error_type) {
    110   switch (error_type) {
    111     case sync_pb::SyncEnums::SUCCESS:
    112       return SYNC_SUCCESS;
    113     case sync_pb::SyncEnums::NOT_MY_BIRTHDAY:
    114       return NOT_MY_BIRTHDAY;
    115     case sync_pb::SyncEnums::THROTTLED:
    116       return THROTTLED;
    117     case sync_pb::SyncEnums::CLEAR_PENDING:
    118       return CLEAR_PENDING;
    119     case sync_pb::SyncEnums::TRANSIENT_ERROR:
    120       return TRANSIENT_ERROR;
    121     case sync_pb::SyncEnums::MIGRATION_DONE:
    122       return MIGRATION_DONE;
    123     case sync_pb::SyncEnums::DISABLED_BY_ADMIN:
    124       return DISABLED_BY_ADMIN;
    125     case sync_pb::SyncEnums::USER_ROLLBACK:
    126       return USER_ROLLBACK;
    127     case sync_pb::SyncEnums::UNKNOWN:
    128       return UNKNOWN_ERROR;
    129     case sync_pb::SyncEnums::USER_NOT_ACTIVATED:
    130     case sync_pb::SyncEnums::AUTH_INVALID:
    131     case sync_pb::SyncEnums::ACCESS_DENIED:
    132       return INVALID_CREDENTIAL;
    133     default:
    134       NOTREACHED();
    135       return UNKNOWN_ERROR;
    136   }
    137 }
    138 
    139 ClientAction ConvertClientActionPBToLocalClientAction(
    140     const sync_pb::SyncEnums::Action& action) {
    141   switch (action) {
    142     case sync_pb::SyncEnums::UPGRADE_CLIENT:
    143       return UPGRADE_CLIENT;
    144     case sync_pb::SyncEnums::CLEAR_USER_DATA_AND_RESYNC:
    145       return CLEAR_USER_DATA_AND_RESYNC;
    146     case sync_pb::SyncEnums::ENABLE_SYNC_ON_ACCOUNT:
    147       return ENABLE_SYNC_ON_ACCOUNT;
    148     case sync_pb::SyncEnums::STOP_AND_RESTART_SYNC:
    149       return STOP_AND_RESTART_SYNC;
    150     case sync_pb::SyncEnums::DISABLE_SYNC_ON_CLIENT:
    151       return DISABLE_SYNC_ON_CLIENT;
    152     case sync_pb::SyncEnums::UNKNOWN_ACTION:
    153       return UNKNOWN_ACTION;
    154     default:
    155       NOTREACHED();
    156       return UNKNOWN_ACTION;
    157   }
    158 }
    159 
    160 }  // namespace
    161 
    162 ModelTypeSet GetTypesToMigrate(const ClientToServerResponse& response) {
    163   ModelTypeSet to_migrate;
    164   for (int i = 0; i < response.migrated_data_type_id_size(); i++) {
    165     int field_number = response.migrated_data_type_id(i);
    166     ModelType model_type = GetModelTypeFromSpecificsFieldNumber(field_number);
    167     if (!IsRealDataType(model_type)) {
    168       DLOG(WARNING) << "Unknown field number " << field_number;
    169       continue;
    170     }
    171     to_migrate.Put(model_type);
    172   }
    173   return to_migrate;
    174 }
    175 
    176 SyncProtocolError ConvertErrorPBToLocalType(
    177     const sync_pb::ClientToServerResponse_Error& error) {
    178   SyncProtocolError sync_protocol_error;
    179   sync_protocol_error.error_type = ConvertSyncProtocolErrorTypePBToLocalType(
    180       error.error_type());
    181   sync_protocol_error.error_description = error.error_description();
    182   sync_protocol_error.url = error.url();
    183   sync_protocol_error.action = ConvertClientActionPBToLocalClientAction(
    184       error.action());
    185 
    186   if (error.error_data_type_ids_size() > 0) {
    187     // THROTTLED is currently the only error code that uses |error_data_types|.
    188     DCHECK_EQ(error.error_type(), sync_pb::SyncEnums::THROTTLED);
    189     for (int i = 0; i < error.error_data_type_ids_size(); ++i) {
    190       int field_number = error.error_data_type_ids(i);
    191       ModelType model_type =
    192           GetModelTypeFromSpecificsFieldNumber(field_number);
    193       if (!IsRealDataType(model_type)) {
    194         DLOG(WARNING) << "Unknown field number " << field_number;
    195         continue;
    196       }
    197       sync_protocol_error.error_data_types.Put(model_type);
    198     }
    199   }
    200 
    201   return sync_protocol_error;
    202 }
    203 
    204 // static
    205 bool SyncerProtoUtil::VerifyResponseBirthday(
    206     const ClientToServerResponse& response,
    207     syncable::Directory* dir) {
    208 
    209   std::string local_birthday = dir->store_birthday();
    210 
    211   if (local_birthday.empty()) {
    212     if (!response.has_store_birthday()) {
    213       LOG(WARNING) << "Expected a birthday on first sync.";
    214       return false;
    215     }
    216 
    217     DVLOG(1) << "New store birthday: " << response.store_birthday();
    218     dir->set_store_birthday(response.store_birthday());
    219     return true;
    220   }
    221 
    222   // Error situation, but we're not stuck.
    223   if (!response.has_store_birthday()) {
    224     LOG(WARNING) << "No birthday in server response?";
    225     return true;
    226   }
    227 
    228   if (response.store_birthday() != local_birthday) {
    229     LOG(WARNING) << "Birthday changed, showing syncer stuck";
    230     return false;
    231   }
    232 
    233   return true;
    234 }
    235 
    236 // static
    237 bool SyncerProtoUtil::IsSyncDisabledByAdmin(
    238     const sync_pb::ClientToServerResponse& response) {
    239   return (response.has_error_code() &&
    240           response.error_code() == sync_pb::SyncEnums::DISABLED_BY_ADMIN);
    241 }
    242 
    243 // static
    244 void SyncerProtoUtil::AddRequestBirthday(syncable::Directory* dir,
    245                                          ClientToServerMessage* msg) {
    246   if (!dir->store_birthday().empty())
    247     msg->set_store_birthday(dir->store_birthday());
    248 }
    249 
    250 // static
    251 void SyncerProtoUtil::AddBagOfChips(syncable::Directory* dir,
    252                                     ClientToServerMessage* msg) {
    253   msg->mutable_bag_of_chips()->ParseFromString(dir->bag_of_chips());
    254 }
    255 
    256 // static
    257 void SyncerProtoUtil::SetProtocolVersion(ClientToServerMessage* msg) {
    258   const int current_version =
    259       ClientToServerMessage::default_instance().protocol_version();
    260   msg->set_protocol_version(current_version);
    261 }
    262 
    263 // static
    264 bool SyncerProtoUtil::PostAndProcessHeaders(ServerConnectionManager* scm,
    265                                             sessions::SyncSession* session,
    266                                             const ClientToServerMessage& msg,
    267                                             ClientToServerResponse* response) {
    268   ServerConnectionManager::PostBufferParams params;
    269   DCHECK(msg.has_protocol_version());
    270   DCHECK_EQ(msg.protocol_version(),
    271             ClientToServerMessage::default_instance().protocol_version());
    272   msg.SerializeToString(&params.buffer_in);
    273 
    274   ScopedServerStatusWatcher server_status_watcher(scm, &params.response);
    275   // Fills in params.buffer_out and params.response.
    276   if (!scm->PostBufferWithCachedAuth(&params, &server_status_watcher)) {
    277     LOG(WARNING) << "Error posting from syncer:" << params.response;
    278     return false;
    279   }
    280 
    281   if (response->ParseFromString(params.buffer_out)) {
    282     // TODO(tim): This is an egregious layering violation (bug 35060).
    283     switch (response->error_code()) {
    284       case sync_pb::SyncEnums::ACCESS_DENIED:
    285       case sync_pb::SyncEnums::AUTH_INVALID:
    286       case sync_pb::SyncEnums::USER_NOT_ACTIVATED:
    287         // Fires on ScopedServerStatusWatcher
    288         params.response.server_status = HttpResponse::SYNC_AUTH_ERROR;
    289         return false;
    290       default:
    291         return true;
    292     }
    293   }
    294 
    295   return false;
    296 }
    297 
    298 base::TimeDelta SyncerProtoUtil::GetThrottleDelay(
    299     const ClientToServerResponse& response) {
    300   base::TimeDelta throttle_delay =
    301       base::TimeDelta::FromSeconds(kSyncDelayAfterThrottled);
    302   if (response.has_client_command()) {
    303     const sync_pb::ClientCommand& command = response.client_command();
    304     if (command.has_throttle_delay_seconds()) {
    305       throttle_delay =
    306           base::TimeDelta::FromSeconds(command.throttle_delay_seconds());
    307     }
    308   }
    309   return throttle_delay;
    310 }
    311 
    312 namespace {
    313 
    314 // Helper function for an assertion in PostClientToServerMessage.
    315 bool IsVeryFirstGetUpdates(const ClientToServerMessage& message) {
    316   if (!message.has_get_updates())
    317     return false;
    318   DCHECK_LT(0, message.get_updates().from_progress_marker_size());
    319   for (int i = 0; i < message.get_updates().from_progress_marker_size(); ++i) {
    320     if (!message.get_updates().from_progress_marker(i).token().empty())
    321       return false;
    322   }
    323   return true;
    324 }
    325 
    326 // TODO(lipalani) : Rename these function names as per the CR for issue 7740067.
    327 SyncProtocolError ConvertLegacyErrorCodeToNewError(
    328     const sync_pb::SyncEnums::ErrorType& error_type) {
    329   SyncProtocolError error;
    330   error.error_type = ConvertSyncProtocolErrorTypePBToLocalType(error_type);
    331   if (error_type == sync_pb::SyncEnums::CLEAR_PENDING ||
    332       error_type == sync_pb::SyncEnums::NOT_MY_BIRTHDAY) {
    333     error.action = DISABLE_SYNC_ON_CLIENT;
    334   } else if (error_type == sync_pb::SyncEnums::DISABLED_BY_ADMIN) {
    335     error.action = STOP_SYNC_FOR_DISABLED_ACCOUNT;
    336   } else if (error_type == sync_pb::SyncEnums::USER_ROLLBACK) {
    337     error.action = DISABLE_SYNC_AND_ROLLBACK;
    338   } // There is no other action we can compute for legacy server.
    339   return error;
    340 }
    341 
    342 }  // namespace
    343 
    344 // static
    345 SyncerError SyncerProtoUtil::PostClientToServerMessage(
    346     ClientToServerMessage* msg,
    347     ClientToServerResponse* response,
    348     SyncSession* session) {
    349   CHECK(response);
    350   DCHECK(!msg->get_updates().has_from_timestamp());  // Deprecated.
    351   DCHECK(!msg->get_updates().has_requested_types());  // Deprecated.
    352 
    353   // Add must-have fields.
    354   SetProtocolVersion(msg);
    355   AddRequestBirthday(session->context()->directory(), msg);
    356   DCHECK(msg->has_store_birthday() || IsVeryFirstGetUpdates(*msg));
    357   AddBagOfChips(session->context()->directory(), msg);
    358   msg->set_api_key(google_apis::GetAPIKey());
    359   msg->mutable_client_status()->CopyFrom(session->context()->client_status());
    360   msg->set_invalidator_client_id(session->context()->invalidator_client_id());
    361 
    362   syncable::Directory* dir = session->context()->directory();
    363 
    364   LogClientToServerMessage(*msg);
    365   if (!PostAndProcessHeaders(session->context()->connection_manager(), session,
    366                              *msg, response)) {
    367     // There was an error establishing communication with the server.
    368     // We can not proceed beyond this point.
    369     const HttpResponse::ServerConnectionCode server_status =
    370         session->context()->connection_manager()->server_status();
    371 
    372     DCHECK_NE(server_status, HttpResponse::NONE);
    373     DCHECK_NE(server_status, HttpResponse::SERVER_CONNECTION_OK);
    374 
    375     return ServerConnectionErrorAsSyncerError(server_status);
    376   }
    377   LogClientToServerResponse(*response);
    378 
    379   // Persist a bag of chips if it has been sent by the server.
    380   PersistBagOfChips(dir, *response);
    381 
    382   SyncProtocolError sync_protocol_error;
    383 
    384   // The DISABLED_BY_ADMIN error overrides other errors sent by the server.
    385   if (IsSyncDisabledByAdmin(*response)) {
    386     sync_protocol_error.error_type = DISABLED_BY_ADMIN;
    387     sync_protocol_error.action = STOP_SYNC_FOR_DISABLED_ACCOUNT;
    388   } else if (!VerifyResponseBirthday(*response, dir)) {
    389     // If sync isn't disabled, first check for a birthday mismatch error.
    390     sync_protocol_error.error_type = NOT_MY_BIRTHDAY;
    391     sync_protocol_error.action = DISABLE_SYNC_ON_CLIENT;
    392   } else if (response->has_error()) {
    393     // This is a new server. Just get the error from the protocol.
    394     sync_protocol_error = ConvertErrorPBToLocalType(response->error());
    395   } else {
    396     // Legacy server implementation. Compute the error based on |error_code|.
    397     sync_protocol_error = ConvertLegacyErrorCodeToNewError(
    398         response->error_code());
    399   }
    400 
    401   // Inform the delegate of the error we got.
    402   session->delegate()->OnSyncProtocolError(sync_protocol_error);
    403 
    404   // Update our state for any other commands we've received.
    405   if (response->has_client_command()) {
    406     const sync_pb::ClientCommand& command = response->client_command();
    407     if (command.has_max_commit_batch_size()) {
    408       session->context()->set_max_commit_batch_size(
    409           command.max_commit_batch_size());
    410     }
    411 
    412     if (command.has_set_sync_long_poll_interval()) {
    413       session->delegate()->OnReceivedLongPollIntervalUpdate(
    414           base::TimeDelta::FromSeconds(command.set_sync_long_poll_interval()));
    415     }
    416 
    417     if (command.has_set_sync_poll_interval()) {
    418       session->delegate()->OnReceivedShortPollIntervalUpdate(
    419           base::TimeDelta::FromSeconds(command.set_sync_poll_interval()));
    420     }
    421 
    422     if (command.has_sessions_commit_delay_seconds()) {
    423       session->delegate()->OnReceivedSessionsCommitDelay(
    424           base::TimeDelta::FromSeconds(
    425               command.sessions_commit_delay_seconds()));
    426     }
    427 
    428     if (command.has_client_invalidation_hint_buffer_size()) {
    429       session->delegate()->OnReceivedClientInvalidationHintBufferSize(
    430           command.client_invalidation_hint_buffer_size());
    431     }
    432 
    433     if (command.has_gu_retry_delay_seconds()) {
    434       session->delegate()->OnReceivedGuRetryDelay(
    435           base::TimeDelta::FromSeconds(command.gu_retry_delay_seconds()));
    436     }
    437   }
    438 
    439   // Now do any special handling for the error type and decide on the return
    440   // value.
    441   switch (sync_protocol_error.error_type) {
    442     case UNKNOWN_ERROR:
    443       LOG(WARNING) << "Sync protocol out-of-date. The server is using a more "
    444                    << "recent version.";
    445       return SERVER_RETURN_UNKNOWN_ERROR;
    446     case SYNC_SUCCESS:
    447       LogResponseProfilingData(*response);
    448       return SYNCER_OK;
    449     case THROTTLED:
    450       if (sync_protocol_error.error_data_types.Empty()) {
    451         DLOG(WARNING) << "Client fully throttled by syncer.";
    452         session->delegate()->OnThrottled(GetThrottleDelay(*response));
    453       } else {
    454         DLOG(WARNING) << "Some types throttled by syncer.";
    455         session->delegate()->OnTypesThrottled(
    456             sync_protocol_error.error_data_types,
    457             GetThrottleDelay(*response));
    458       }
    459       return SERVER_RETURN_THROTTLED;
    460     case TRANSIENT_ERROR:
    461       return SERVER_RETURN_TRANSIENT_ERROR;
    462     case MIGRATION_DONE:
    463       LOG_IF(ERROR, 0 >= response->migrated_data_type_id_size())
    464           << "MIGRATION_DONE but no types specified.";
    465       session->delegate()->OnReceivedMigrationRequest(
    466           GetTypesToMigrate(*response));
    467       return SERVER_RETURN_MIGRATION_DONE;
    468     case CLEAR_PENDING:
    469       return SERVER_RETURN_CLEAR_PENDING;
    470     case NOT_MY_BIRTHDAY:
    471       return SERVER_RETURN_NOT_MY_BIRTHDAY;
    472     case DISABLED_BY_ADMIN:
    473       return SERVER_RETURN_DISABLED_BY_ADMIN;
    474     case USER_ROLLBACK:
    475       return SERVER_RETURN_USER_ROLLBACK;
    476     default:
    477       NOTREACHED();
    478       return UNSET;
    479   }
    480 }
    481 
    482 // static
    483 bool SyncerProtoUtil::ShouldMaintainPosition(
    484     const sync_pb::SyncEntity& sync_entity) {
    485   // Maintain positions for bookmarks that are not server-defined top-level
    486   // folders.
    487   return GetModelType(sync_entity) == BOOKMARKS
    488       && !(sync_entity.folder() &&
    489            !sync_entity.server_defined_unique_tag().empty());
    490 }
    491 
    492 // static
    493 void SyncerProtoUtil::CopyProtoBytesIntoBlob(const std::string& proto_bytes,
    494                                              syncable::Blob* blob) {
    495   syncable::Blob proto_blob(proto_bytes.begin(), proto_bytes.end());
    496   blob->swap(proto_blob);
    497 }
    498 
    499 // static
    500 bool SyncerProtoUtil::ProtoBytesEqualsBlob(const std::string& proto_bytes,
    501                                            const syncable::Blob& blob) {
    502   if (proto_bytes.size() != blob.size())
    503     return false;
    504   return std::equal(proto_bytes.begin(), proto_bytes.end(), blob.begin());
    505 }
    506 
    507 // static
    508 void SyncerProtoUtil::CopyBlobIntoProtoBytes(const syncable::Blob& blob,
    509                                              std::string* proto_bytes) {
    510   std::string blob_string(blob.begin(), blob.end());
    511   proto_bytes->swap(blob_string);
    512 }
    513 
    514 // static
    515 const std::string& SyncerProtoUtil::NameFromSyncEntity(
    516     const sync_pb::SyncEntity& entry) {
    517   if (entry.has_non_unique_name())
    518     return entry.non_unique_name();
    519   return entry.name();
    520 }
    521 
    522 // static
    523 const std::string& SyncerProtoUtil::NameFromCommitEntryResponse(
    524     const sync_pb::CommitResponse_EntryResponse& entry) {
    525   if (entry.has_non_unique_name())
    526     return entry.non_unique_name();
    527   return entry.name();
    528 }
    529 
    530 // static
    531 void SyncerProtoUtil::PersistBagOfChips(syncable::Directory* dir,
    532     const sync_pb::ClientToServerResponse& response) {
    533   if (!response.has_new_bag_of_chips())
    534     return;
    535   std::string bag_of_chips;
    536   if (response.new_bag_of_chips().SerializeToString(&bag_of_chips))
    537     dir->set_bag_of_chips(bag_of_chips);
    538 }
    539 
    540 std::string SyncerProtoUtil::SyncEntityDebugString(
    541     const sync_pb::SyncEntity& entry) {
    542   const std::string& mtime_str =
    543       GetTimeDebugString(ProtoTimeToTime(entry.mtime()));
    544   const std::string& ctime_str =
    545       GetTimeDebugString(ProtoTimeToTime(entry.ctime()));
    546   return base::StringPrintf(
    547       "id: %s, parent_id: %s, "
    548       "version: %" PRId64"d, "
    549       "mtime: %" PRId64"d (%s), "
    550       "ctime: %" PRId64"d (%s), "
    551       "name: %s, sync_timestamp: %" PRId64"d, "
    552       "%s ",
    553       entry.id_string().c_str(),
    554       entry.parent_id_string().c_str(),
    555       entry.version(),
    556       entry.mtime(), mtime_str.c_str(),
    557       entry.ctime(), ctime_str.c_str(),
    558       entry.name().c_str(), entry.sync_timestamp(),
    559       entry.deleted() ? "deleted, ":"");
    560 }
    561 
    562 namespace {
    563 std::string GetUpdatesResponseString(
    564     const sync_pb::GetUpdatesResponse& response) {
    565   std::string output;
    566   output.append("GetUpdatesResponse:\n");
    567   for (int i = 0; i < response.entries_size(); i++) {
    568     output.append(SyncerProtoUtil::SyncEntityDebugString(response.entries(i)));
    569     output.append("\n");
    570   }
    571   return output;
    572 }
    573 }  // namespace
    574 
    575 std::string SyncerProtoUtil::ClientToServerResponseDebugString(
    576     const ClientToServerResponse& response) {
    577   // Add more handlers as needed.
    578   std::string output;
    579   if (response.has_get_updates())
    580     output.append(GetUpdatesResponseString(response.get_updates()));
    581   return output;
    582 }
    583 
    584 }  // namespace syncer
    585