components/sync_driver/generic_change_processor.cc

   1 // Copyright 2014 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 "components/sync_driver/generic_change_processor.h"
   6
   7 #include "base/location.h"
   8 #include "base/strings/string_number_conversions.h"
   9 #include "base/strings/utf_string_conversions.h"
  10 #include "base/thread_task_runner_handle.h"
  11 #include "components/sync_driver/sync_api_component_factory.h"
  12 #include "sync/api/sync_change.h"
  13 #include "sync/api/sync_error.h"
  14 #include "sync/api/syncable_service.h"
  15 #include "sync/internal_api/public/base_node.h"
  16 #include "sync/internal_api/public/change_record.h"
  17 #include "sync/internal_api/public/read_node.h"
  18 #include "sync/internal_api/public/read_transaction.h"
  19 #include "sync/internal_api/public/util/unrecoverable_error_handler.h"
  20 #include "sync/internal_api/public/write_node.h"
  21 #include "sync/internal_api/public/write_transaction.h"
  22 #include "sync/syncable/entry.h"  // TODO(tim): Bug 123674.
  23
  24 namespace sync_driver {
  25
  26 namespace {
  27
  28 const int kContextSizeLimit = 1024;  // Datatype context size limit.
  29
  30 void SetNodeSpecifics(const sync_pb::EntitySpecifics& entity_specifics,
  31                       syncer::WriteNode* write_node) {
  32   if (syncer::GetModelTypeFromSpecifics(entity_specifics) ==
  33           syncer::PASSWORDS) {
  34     write_node->SetPasswordSpecifics(
  35         entity_specifics.password().client_only_encrypted_data());
  36   } else {
  37     write_node->SetEntitySpecifics(entity_specifics);
  38   }
  39 }
  40
  41 // Helper function to convert AttachmentId to AttachmentMetadataRecord.
  42 sync_pb::AttachmentMetadataRecord AttachmentIdToRecord(
  43     const syncer::AttachmentId& attachment_id) {
  44   sync_pb::AttachmentMetadataRecord record;
  45   *record.mutable_id() = attachment_id.GetProto();
  46   return record;
  47 }
  48
  49 // Replace |write_nodes|'s attachment ids with |attachment_ids|.
  50 void SetAttachmentMetadata(const syncer::AttachmentIdList& attachment_ids,
  51                            syncer::WriteNode* write_node) {
  52   DCHECK(write_node);
  53   sync_pb::AttachmentMetadata attachment_metadata;
  54   std::transform(
  55       attachment_ids.begin(),
  56       attachment_ids.end(),
  57       RepeatedFieldBackInserter(attachment_metadata.mutable_record()),
  58       AttachmentIdToRecord);
  59   write_node->SetAttachmentMetadata(attachment_metadata);
  60 }
  61
  62 syncer::SyncData BuildRemoteSyncData(
  63     int64 sync_id,
  64     const syncer::BaseNode& read_node,
  65     const syncer::AttachmentServiceProxy& attachment_service_proxy) {
  66   const syncer::AttachmentIdList& attachment_ids = read_node.GetAttachmentIds();
  67   // Use the specifics of non-password datatypes directly (encryption has
  68   // already been handled).
  69   if (read_node.GetModelType() != syncer::PASSWORDS) {
  70     return syncer::SyncData::CreateRemoteData(sync_id,
  71                                               read_node.GetEntitySpecifics(),
  72                                               read_node.GetModificationTime(),
  73                                               attachment_ids,
  74                                               attachment_service_proxy);
  75   }
  76
  77   // Passwords must be accessed differently, to account for their encryption,
  78   // and stored into a temporary EntitySpecifics.
  79   sync_pb::EntitySpecifics password_holder;
  80   password_holder.mutable_password()->mutable_client_only_encrypted_data()->
  81       CopyFrom(read_node.GetPasswordSpecifics());
  82   return syncer::SyncData::CreateRemoteData(sync_id,
  83                                             password_holder,
  84                                             read_node.GetModificationTime(),
  85                                             attachment_ids,
  86                                             attachment_service_proxy);
  87 }
  88
  89 }  // namespace
  90
  91 GenericChangeProcessor::GenericChangeProcessor(
  92     syncer::ModelType type,
  93     DataTypeErrorHandler* error_handler,
  94     const base::WeakPtr<syncer::SyncableService>& local_service,
  95     const base::WeakPtr<syncer::SyncMergeResult>& merge_result,
  96     syncer::UserShare* user_share,
  97     SyncApiComponentFactory* sync_factory,
  98     scoped_ptr<syncer::AttachmentStoreForSync> attachment_store)
  99     : ChangeProcessor(error_handler),
 100       type_(type),
 101       local_service_(local_service),
 102       merge_result_(merge_result),
 103       share_handle_(user_share),
 104       weak_ptr_factory_(this) {
 105   DCHECK(CalledOnValidThread());
 106   DCHECK_NE(type_, syncer::UNSPECIFIED);
 107   if (attachment_store) {
 108     std::string store_birthday;
 109     {
 110       syncer::ReadTransaction trans(FROM_HERE, share_handle());
 111       store_birthday = trans.GetStoreBirthday();
 112     }
 113     attachment_service_ = sync_factory->CreateAttachmentService(
 114         attachment_store.Pass(), *user_share, store_birthday, type, this);
 115     attachment_service_weak_ptr_factory_.reset(
 116         new base::WeakPtrFactory<syncer::AttachmentService>(
 117             attachment_service_.get()));
 118     attachment_service_proxy_ = syncer::AttachmentServiceProxy(
 119         base::ThreadTaskRunnerHandle::Get(),
 120         attachment_service_weak_ptr_factory_->GetWeakPtr());
 121     UploadAllAttachmentsNotOnServer();
 122   } else {
 123     attachment_service_proxy_ = syncer::AttachmentServiceProxy(
 124         base::ThreadTaskRunnerHandle::Get(),
 125         base::WeakPtr<syncer::AttachmentService>());
 126   }
 127 }
 128
 129 GenericChangeProcessor::~GenericChangeProcessor() {
 130   DCHECK(CalledOnValidThread());
 131 }
 132
 133 void GenericChangeProcessor::ApplyChangesFromSyncModel(
 134     const syncer::BaseTransaction* trans,
 135     int64 model_version,
 136     const syncer::ImmutableChangeRecordList& changes) {
 137   DCHECK(CalledOnValidThread());
 138   DCHECK(syncer_changes_.empty());
 139   for (syncer::ChangeRecordList::const_iterator it =
 140            changes.Get().begin(); it != changes.Get().end(); ++it) {
 141     if (it->action == syncer::ChangeRecord::ACTION_DELETE) {
 142       scoped_ptr<sync_pb::EntitySpecifics> specifics;
 143       if (it->specifics.has_password()) {
 144         DCHECK(it->extra.get());
 145         specifics.reset(new sync_pb::EntitySpecifics(it->specifics));
 146         specifics->mutable_password()->mutable_client_only_encrypted_data()->
 147             CopyFrom(it->extra->unencrypted());
 148       }
 149       const syncer::AttachmentIdList empty_list_of_attachment_ids;
 150       syncer_changes_.push_back(syncer::SyncChange(
 151           FROM_HERE, syncer::SyncChange::ACTION_DELETE,
 152           syncer::SyncData::CreateRemoteData(
 153               it->id, specifics ? *specifics : it->specifics, base::Time(),
 154               empty_list_of_attachment_ids, attachment_service_proxy_)));
 155     } else {
 156       syncer::SyncChange::SyncChangeType action =
 157           (it->action == syncer::ChangeRecord::ACTION_ADD) ?
 158           syncer::SyncChange::ACTION_ADD : syncer::SyncChange::ACTION_UPDATE;
 159       // Need to load specifics from node.
 160       syncer::ReadNode read_node(trans);
 161       if (read_node.InitByIdLookup(it->id) != syncer::BaseNode::INIT_OK) {
 162         syncer::SyncError error(
 163             FROM_HERE,
 164             syncer::SyncError::DATATYPE_ERROR,
 165             "Failed to look up data for received change with id " +
 166                 base::Int64ToString(it->id),
 167             syncer::GetModelTypeFromSpecifics(it->specifics));
 168         error_handler()->OnSingleDataTypeUnrecoverableError(error);
 169         return;
 170       }
 171       syncer_changes_.push_back(syncer::SyncChange(
 172           FROM_HERE, action,
 173           BuildRemoteSyncData(it->id, read_node, attachment_service_proxy_)));
 174     }
 175   }
 176 }
 177
 178 void GenericChangeProcessor::CommitChangesFromSyncModel() {
 179   DCHECK(CalledOnValidThread());
 180   if (syncer_changes_.empty())
 181     return;
 182   if (!local_service_.get()) {
 183     syncer::ModelType type = syncer_changes_[0].sync_data().GetDataType();
 184     syncer::SyncError error(FROM_HERE,
 185                             syncer::SyncError::DATATYPE_ERROR,
 186                             "Local service destroyed.",
 187                             type);
 188     error_handler()->OnSingleDataTypeUnrecoverableError(error);
 189     return;
 190   }
 191   syncer::SyncError error = local_service_->ProcessSyncChanges(FROM_HERE,
 192                                                        syncer_changes_);
 193   syncer_changes_.clear();
 194   if (error.IsSet())
 195     error_handler()->OnSingleDataTypeUnrecoverableError(error);
 196 }
 197
 198 syncer::SyncDataList GenericChangeProcessor::GetAllSyncData(
 199     syncer::ModelType type) const {
 200   DCHECK_EQ(type_, type);
 201   // This is slow / memory intensive.  Should be used sparingly by datatypes.
 202   syncer::SyncDataList data;
 203   GetAllSyncDataReturnError(&data);
 204   return data;
 205 }
 206
 207 syncer::SyncError GenericChangeProcessor::UpdateDataTypeContext(
 208     syncer::ModelType type,
 209     syncer::SyncChangeProcessor::ContextRefreshStatus refresh_status,
 210     const std::string& context) {
 211   DCHECK(syncer::ProtocolTypes().Has(type));
 212   DCHECK_EQ(type_, type);
 213
 214   if (context.size() > static_cast<size_t>(kContextSizeLimit)) {
 215     return syncer::SyncError(FROM_HERE,
 216                              syncer::SyncError::DATATYPE_ERROR,
 217                              "Context size limit exceeded.",
 218                              type);
 219   }
 220
 221   syncer::WriteTransaction trans(FROM_HERE, share_handle());
 222   trans.SetDataTypeContext(type, refresh_status, context);
 223
 224   // TODO(zea): plumb a pointer to the PSS or SyncManagerImpl here so we can
 225   // trigger a datatype nudge if |refresh_status == REFRESH_NEEDED|.
 226
 227   return syncer::SyncError();
 228 }
 229
 230 void GenericChangeProcessor::OnAttachmentUploaded(
 231     const syncer::AttachmentId& attachment_id) {
 232   syncer::WriteTransaction trans(FROM_HERE, share_handle());
 233   trans.UpdateEntriesMarkAttachmentAsOnServer(attachment_id);
 234 }
 235
 236 syncer::SyncError GenericChangeProcessor::GetAllSyncDataReturnError(
 237     syncer::SyncDataList* current_sync_data) const {
 238   DCHECK(CalledOnValidThread());
 239   std::string type_name = syncer::ModelTypeToString(type_);
 240   syncer::ReadTransaction trans(FROM_HERE, share_handle());
 241   syncer::ReadNode root(&trans);
 242   if (root.InitTypeRoot(type_) != syncer::BaseNode::INIT_OK) {
 243     syncer::SyncError error(FROM_HERE,
 244                             syncer::SyncError::DATATYPE_ERROR,
 245                             "Server did not create the top-level " + type_name +
 246                                 " node. We might be running against an out-of-"
 247                                 "date server.",
 248                             type_);
 249     return error;
 250   }
 251
 252   // TODO(akalin): We'll have to do a tree traversal for bookmarks.
 253   DCHECK_NE(type_, syncer::BOOKMARKS);
 254
 255   std::vector<int64> child_ids;
 256   root.GetChildIds(&child_ids);
 257
 258   for (std::vector<int64>::iterator it = child_ids.begin();
 259        it != child_ids.end(); ++it) {
 260     syncer::ReadNode sync_child_node(&trans);
 261     if (sync_child_node.InitByIdLookup(*it) !=
 262             syncer::BaseNode::INIT_OK) {
 263       syncer::SyncError error(
 264           FROM_HERE,
 265           syncer::SyncError::DATATYPE_ERROR,
 266           "Failed to fetch child node for type " + type_name + ".",
 267           type_);
 268       return error;
 269     }
 270     current_sync_data->push_back(BuildRemoteSyncData(
 271         sync_child_node.GetId(), sync_child_node, attachment_service_proxy_));
 272   }
 273   return syncer::SyncError();
 274 }
 275
 276 bool GenericChangeProcessor::GetDataTypeContext(std::string* context) const {
 277   syncer::ReadTransaction trans(FROM_HERE, share_handle());
 278   sync_pb::DataTypeContext context_proto;
 279   trans.GetDataTypeContext(type_, &context_proto);
 280   if (!context_proto.has_context())
 281     return false;
 282
 283   DCHECK_EQ(type_,
 284             syncer::GetModelTypeFromSpecificsFieldNumber(
 285                 context_proto.data_type_id()));
 286   *context = context_proto.context();
 287   return true;
 288 }
 289
 290 int GenericChangeProcessor::GetSyncCount() {
 291   syncer::ReadTransaction trans(FROM_HERE, share_handle());
 292   syncer::ReadNode root(&trans);
 293   if (root.InitTypeRoot(type_) != syncer::BaseNode::INIT_OK)
 294     return 0;
 295
 296   // Subtract one to account for type's root node.
 297   return root.GetTotalNodeCount() - 1;
 298 }
 299
 300 namespace {
 301
 302 // WARNING: this code is sensitive to compiler optimizations. Be careful
 303 // modifying any code around an OnSingleDataTypeUnrecoverableError call, else
 304 // the compiler attempts to merge it with other calls, losing useful information
 305 // in breakpad uploads.
 306 syncer::SyncError LogLookupFailure(
 307     syncer::BaseNode::InitByLookupResult lookup_result,
 308     const tracked_objects::Location& from_here,
 309     const std::string& error_prefix,
 310     syncer::ModelType type,
 311     DataTypeErrorHandler* error_handler) {
 312   switch (lookup_result) {
 313     case syncer::BaseNode::INIT_FAILED_ENTRY_NOT_GOOD: {
 314       syncer::SyncError error;
 315       error.Reset(from_here,
 316                   error_prefix +
 317                       "could not find entry matching the lookup criteria.",
 318                   type);
 319       error_handler->OnSingleDataTypeUnrecoverableError(error);
 320       LOG(ERROR) << "Delete: Bad entry.";
 321       return error;
 322     }
 323     case syncer::BaseNode::INIT_FAILED_ENTRY_IS_DEL: {
 324       syncer::SyncError error;
 325       error.Reset(from_here, error_prefix + "entry is already deleted.", type);
 326       error_handler->OnSingleDataTypeUnrecoverableError(error);
 327       LOG(ERROR) << "Delete: Deleted entry.";
 328       return error;
 329     }
 330     case syncer::BaseNode::INIT_FAILED_DECRYPT_IF_NECESSARY: {
 331       syncer::SyncError error;
 332       error.Reset(from_here, error_prefix + "unable to decrypt", type);
 333       error_handler->OnSingleDataTypeUnrecoverableError(error);
 334       LOG(ERROR) << "Delete: Undecryptable entry.";
 335       return error;
 336     }
 337     case syncer::BaseNode::INIT_FAILED_PRECONDITION: {
 338       syncer::SyncError error;
 339       error.Reset(from_here,
 340                   error_prefix + "a precondition was not met for calling init.",
 341                   type);
 342       error_handler->OnSingleDataTypeUnrecoverableError(error);
 343       LOG(ERROR) << "Delete: Failed precondition.";
 344       return error;
 345     }
 346     default: {
 347       syncer::SyncError error;
 348       // Should have listed all the possible error cases above.
 349       error.Reset(from_here, error_prefix + "unknown error", type);
 350       error_handler->OnSingleDataTypeUnrecoverableError(error);
 351       LOG(ERROR) << "Delete: Unknown error.";
 352       return error;
 353     }
 354   }
 355 }
 356
 357 syncer::SyncError AttemptDelete(const syncer::SyncChange& change,
 358                                 syncer::ModelType type,
 359                                 const std::string& type_str,
 360                                 syncer::WriteNode* node,
 361                                 DataTypeErrorHandler* error_handler) {
 362   DCHECK_EQ(change.change_type(), syncer::SyncChange::ACTION_DELETE);
 363   if (change.sync_data().IsLocal()) {
 364     const std::string& tag = syncer::SyncDataLocal(change.sync_data()).GetTag();
 365     if (tag.empty()) {
 366       syncer::SyncError error(
 367           FROM_HERE,
 368           syncer::SyncError::DATATYPE_ERROR,
 369           "Failed to delete " + type_str + " node. Local data, empty tag. " +
 370               change.location().ToString(),
 371           type);
 372       error_handler->OnSingleDataTypeUnrecoverableError(error);
 373       NOTREACHED();
 374       return error;
 375     }
 376
 377     syncer::BaseNode::InitByLookupResult result =
 378         node->InitByClientTagLookup(change.sync_data().GetDataType(), tag);
 379     if (result != syncer::BaseNode::INIT_OK) {
 380       return LogLookupFailure(
 381           result, FROM_HERE,
 382           "Failed to delete " + type_str + " node. Local data. " +
 383               change.location().ToString(),
 384           type, error_handler);
 385     }
 386   } else {
 387     syncer::BaseNode::InitByLookupResult result = node->InitByIdLookup(
 388         syncer::SyncDataRemote(change.sync_data()).GetId());
 389     if (result != syncer::BaseNode::INIT_OK) {
 390       return LogLookupFailure(
 391           result, FROM_HERE,
 392           "Failed to delete " + type_str + " node. Non-local data. " +
 393               change.location().ToString(),
 394           type, error_handler);
 395     }
 396   }
 397   if (IsActOnceDataType(type))
 398     node->Drop();
 399   else
 400     node->Tombstone();
 401   return syncer::SyncError();
 402 }
 403
 404 }  // namespace
 405
 406 syncer::SyncError GenericChangeProcessor::ProcessSyncChanges(
 407     const tracked_objects::Location& from_here,
 408     const syncer::SyncChangeList& list_of_changes) {
 409   DCHECK(CalledOnValidThread());
 410
 411   // Keep track of brand new attachments so we can persist them on this device
 412   // and upload them to the server.
 413   syncer::AttachmentIdSet new_attachments;
 414
 415   syncer::WriteTransaction trans(from_here, share_handle());
 416
 417   for (syncer::SyncChangeList::const_iterator iter = list_of_changes.begin();
 418        iter != list_of_changes.end();
 419        ++iter) {
 420     const syncer::SyncChange& change = *iter;
 421     DCHECK_EQ(change.sync_data().GetDataType(), type_);
 422     std::string type_str = syncer::ModelTypeToString(type_);
 423     syncer::WriteNode sync_node(&trans);
 424     if (change.change_type() == syncer::SyncChange::ACTION_DELETE) {
 425       syncer::SyncError error =
 426           AttemptDelete(change, type_, type_str, &sync_node, error_handler());
 427       if (error.IsSet()) {
 428         NOTREACHED();
 429         return error;
 430       }
 431       if (merge_result_.get()) {
 432         merge_result_->set_num_items_deleted(
 433             merge_result_->num_items_deleted() + 1);
 434       }
 435     } else if (change.change_type() == syncer::SyncChange::ACTION_ADD) {
 436       syncer::SyncError error = HandleActionAdd(
 437           change, type_str, trans, &sync_node, &new_attachments);
 438       if (error.IsSet()) {
 439         return error;
 440       }
 441     } else if (change.change_type() == syncer::SyncChange::ACTION_UPDATE) {
 442       syncer::SyncError error = HandleActionUpdate(
 443           change, type_str, trans, &sync_node, &new_attachments);
 444       if (error.IsSet()) {
 445         return error;
 446       }
 447     } else {
 448       syncer::SyncError error(
 449           FROM_HERE,
 450           syncer::SyncError::DATATYPE_ERROR,
 451           "Received unset SyncChange in the change processor, " +
 452               change.location().ToString(),
 453           type_);
 454       error_handler()->OnSingleDataTypeUnrecoverableError(error);
 455       NOTREACHED();
 456       LOG(ERROR) << "Unset sync change.";
 457       return error;
 458     }
 459   }
 460
 461   if (!new_attachments.empty()) {
 462     // If datatype uses attachments it should have supplied attachment store
 463     // which would initialize attachment_service_. Fail if it isn't so.
 464     if (!attachment_service_.get()) {
 465       syncer::SyncError error(
 466           FROM_HERE,
 467           syncer::SyncError::DATATYPE_ERROR,
 468           "Datatype performs attachment operation without initializing "
 469           "attachment store",
 470           type_);
 471       error_handler()->OnSingleDataTypeUnrecoverableError(error);
 472       NOTREACHED();
 473       return error;
 474     }
 475     syncer::AttachmentIdList ids_to_upload;
 476     ids_to_upload.reserve(new_attachments.size());
 477     std::copy(new_attachments.begin(), new_attachments.end(),
 478               std::back_inserter(ids_to_upload));
 479     attachment_service_->UploadAttachments(ids_to_upload);
 480   }
 481
 482   return syncer::SyncError();
 483 }
 484
 485 // WARNING: this code is sensitive to compiler optimizations. Be careful
 486 // modifying any code around an OnSingleDataTypeUnrecoverableError call, else
 487 // the compiler attempts to merge it with other calls, losing useful information
 488 // in breakpad uploads.
 489 syncer::SyncError GenericChangeProcessor::HandleActionAdd(
 490     const syncer::SyncChange& change,
 491     const std::string& type_str,
 492     const syncer::WriteTransaction& trans,
 493     syncer::WriteNode* sync_node,
 494     syncer::AttachmentIdSet* new_attachments) {
 495   // TODO(sync): Handle other types of creation (custom parents, folders,
 496   // etc.).
 497   const syncer::SyncDataLocal sync_data_local(change.sync_data());
 498   syncer::WriteNode::InitUniqueByCreationResult result =
 499       sync_node->InitUniqueByCreation(sync_data_local.GetDataType(),
 500                                       sync_data_local.GetTag());
 501   if (result != syncer::WriteNode::INIT_SUCCESS) {
 502     std::string error_prefix = "Failed to create " + type_str + " node: " +
 503                                change.location().ToString() + ", ";
 504     switch (result) {
 505       case syncer::WriteNode::INIT_FAILED_EMPTY_TAG: {
 506         syncer::SyncError error;
 507         error.Reset(FROM_HERE, error_prefix + "empty tag", type_);
 508         error_handler()->OnSingleDataTypeUnrecoverableError(error);
 509         LOG(ERROR) << "Create: Empty tag.";
 510         return error;
 511       }
 512       case syncer::WriteNode::INIT_FAILED_COULD_NOT_CREATE_ENTRY: {
 513         syncer::SyncError error;
 514         error.Reset(FROM_HERE, error_prefix + "failed to create entry", type_);
 515         error_handler()->OnSingleDataTypeUnrecoverableError(error);
 516         LOG(ERROR) << "Create: Could not create entry.";
 517         return error;
 518       }
 519       case syncer::WriteNode::INIT_FAILED_SET_PREDECESSOR: {
 520         syncer::SyncError error;
 521         error.Reset(
 522             FROM_HERE, error_prefix + "failed to set predecessor", type_);
 523         error_handler()->OnSingleDataTypeUnrecoverableError(error);
 524         LOG(ERROR) << "Create: Bad predecessor.";
 525         return error;
 526       }
 527       default: {
 528         syncer::SyncError error;
 529         error.Reset(FROM_HERE, error_prefix + "unknown error", type_);
 530         error_handler()->OnSingleDataTypeUnrecoverableError(error);
 531         LOG(ERROR) << "Create: Unknown error.";
 532         return error;
 533       }
 534     }
 535   }
 536   sync_node->SetTitle(change.sync_data().GetTitle());
 537   SetNodeSpecifics(sync_data_local.GetSpecifics(), sync_node);
 538
 539   syncer::AttachmentIdList attachment_ids = sync_data_local.GetAttachmentIds();
 540   SetAttachmentMetadata(attachment_ids, sync_node);
 541
 542   // Return any newly added attachments.
 543   new_attachments->insert(attachment_ids.begin(), attachment_ids.end());
 544   if (merge_result_.get()) {
 545     merge_result_->set_num_items_added(merge_result_->num_items_added() + 1);
 546   }
 547   return syncer::SyncError();
 548 }
 549 // WARNING: this code is sensitive to compiler optimizations. Be careful
 550 // modifying any code around an OnSingleDataTypeUnrecoverableError call, else
 551 // the compiler attempts to merge it with other calls, losing useful information
 552 // in breakpad uploads.
 553 syncer::SyncError GenericChangeProcessor::HandleActionUpdate(
 554     const syncer::SyncChange& change,
 555     const std::string& type_str,
 556     const syncer::WriteTransaction& trans,
 557     syncer::WriteNode* sync_node,
 558     syncer::AttachmentIdSet* new_attachments) {
 559   const syncer::SyncDataLocal sync_data_local(change.sync_data());
 560   syncer::BaseNode::InitByLookupResult result =
 561       sync_node->InitByClientTagLookup(sync_data_local.GetDataType(),
 562                                        sync_data_local.GetTag());
 563   if (result != syncer::BaseNode::INIT_OK) {
 564     std::string error_prefix = "Failed to load " + type_str + " node. " +
 565                                change.location().ToString() + ", ";
 566     if (result == syncer::BaseNode::INIT_FAILED_PRECONDITION) {
 567       syncer::SyncError error;
 568       error.Reset(FROM_HERE, error_prefix + "empty tag", type_);
 569       error_handler()->OnSingleDataTypeUnrecoverableError(error);
 570       LOG(ERROR) << "Update: Empty tag.";
 571       return error;
 572     } else if (result == syncer::BaseNode::INIT_FAILED_ENTRY_NOT_GOOD) {
 573       syncer::SyncError error;
 574       error.Reset(FROM_HERE, error_prefix + "bad entry", type_);
 575       error_handler()->OnSingleDataTypeUnrecoverableError(error);
 576       LOG(ERROR) << "Update: bad entry.";
 577       return error;
 578     } else if (result == syncer::BaseNode::INIT_FAILED_ENTRY_IS_DEL) {
 579       syncer::SyncError error;
 580       error.Reset(FROM_HERE, error_prefix + "deleted entry", type_);
 581       error_handler()->OnSingleDataTypeUnrecoverableError(error);
 582       LOG(ERROR) << "Update: deleted entry.";
 583       return error;
 584     } else {
 585       syncer::Cryptographer* crypto = trans.GetCryptographer();
 586       syncer::ModelTypeSet encrypted_types(trans.GetEncryptedTypes());
 587       const sync_pb::EntitySpecifics& specifics =
 588           sync_node->GetEntry()->GetSpecifics();
 589       CHECK(specifics.has_encrypted());
 590       const bool can_decrypt = crypto->CanDecrypt(specifics.encrypted());
 591       const bool agreement = encrypted_types.Has(type_);
 592       if (!agreement && !can_decrypt) {
 593         syncer::SyncError error;
 594         error.Reset(FROM_HERE,
 595                     "Failed to load encrypted entry, missing key and "
 596                     "nigori mismatch for " +
 597                         type_str + ".",
 598                     type_);
 599         error_handler()->OnSingleDataTypeUnrecoverableError(error);
 600         LOG(ERROR) << "Update: encr case 1.";
 601         return error;
 602       } else if (agreement && can_decrypt) {
 603         syncer::SyncError error;
 604         error.Reset(FROM_HERE,
 605                     "Failed to load encrypted entry, we have the key "
 606                     "and the nigori matches (?!) for " +
 607                         type_str + ".",
 608                     type_);
 609         error_handler()->OnSingleDataTypeUnrecoverableError(error);
 610         LOG(ERROR) << "Update: encr case 2.";
 611         return error;
 612       } else if (agreement) {
 613         syncer::SyncError error;
 614         error.Reset(FROM_HERE,
 615                     "Failed to load encrypted entry, missing key and "
 616                     "the nigori matches for " +
 617                         type_str + ".",
 618                     type_);
 619         error_handler()->OnSingleDataTypeUnrecoverableError(error);
 620         LOG(ERROR) << "Update: encr case 3.";
 621         return error;
 622       } else {
 623         syncer::SyncError error;
 624         error.Reset(FROM_HERE,
 625                     "Failed to load encrypted entry, we have the key"
 626                     "(?!) and nigori mismatch for " +
 627                         type_str + ".",
 628                     type_);
 629         error_handler()->OnSingleDataTypeUnrecoverableError(error);
 630         LOG(ERROR) << "Update: encr case 4.";
 631         return error;
 632       }
 633     }
 634   }
 635
 636   sync_node->SetTitle(change.sync_data().GetTitle());
 637   SetNodeSpecifics(sync_data_local.GetSpecifics(), sync_node);
 638   syncer::AttachmentIdList attachment_ids = sync_data_local.GetAttachmentIds();
 639   SetAttachmentMetadata(attachment_ids, sync_node);
 640
 641   // Return any newly added attachments.
 642   new_attachments->insert(attachment_ids.begin(), attachment_ids.end());
 643
 644   if (merge_result_.get()) {
 645     merge_result_->set_num_items_modified(merge_result_->num_items_modified() +
 646                                           1);
 647   }
 648   // TODO(sync): Support updating other parts of the sync node (title,
 649   // successor, parent, etc.).
 650   return syncer::SyncError();
 651 }
 652
 653 bool GenericChangeProcessor::SyncModelHasUserCreatedNodes(bool* has_nodes) {
 654   DCHECK(CalledOnValidThread());
 655   DCHECK(has_nodes);
 656   std::string type_name = syncer::ModelTypeToString(type_);
 657   std::string err_str = "Server did not create the top-level " + type_name +
 658       " node. We might be running against an out-of-date server.";
 659   *has_nodes = false;
 660   syncer::ReadTransaction trans(FROM_HERE, share_handle());
 661   syncer::ReadNode type_root_node(&trans);
 662   if (type_root_node.InitTypeRoot(type_) != syncer::BaseNode::INIT_OK) {
 663     LOG(ERROR) << err_str;
 664     return false;
 665   }
 666
 667   // The sync model has user created nodes if the type's root node has any
 668   // children.
 669   *has_nodes = type_root_node.HasChildren();
 670   return true;
 671 }
 672
 673 bool GenericChangeProcessor::CryptoReadyIfNecessary() {
 674   DCHECK(CalledOnValidThread());
 675   // We only access the cryptographer while holding a transaction.
 676   syncer::ReadTransaction trans(FROM_HERE, share_handle());
 677   const syncer::ModelTypeSet encrypted_types = trans.GetEncryptedTypes();
 678   return !encrypted_types.Has(type_) || trans.GetCryptographer()->is_ready();
 679 }
 680
 681 void GenericChangeProcessor::StartImpl() {
 682 }
 683
 684 syncer::UserShare* GenericChangeProcessor::share_handle() const {
 685   DCHECK(CalledOnValidThread());
 686   return share_handle_;
 687 }
 688
 689 void GenericChangeProcessor::UploadAllAttachmentsNotOnServer() {
 690   DCHECK(CalledOnValidThread());
 691   DCHECK(attachment_service_.get());
 692   syncer::AttachmentIdList ids;
 693   {
 694     syncer::ReadTransaction trans(FROM_HERE, share_handle());
 695     trans.GetAttachmentIdsToUpload(type_, &ids);
 696   }
 697   if (!ids.empty()) {
 698     attachment_service_->UploadAttachments(ids);
 699   }
 700 }
 701
 702 scoped_ptr<syncer::AttachmentService>
 703 GenericChangeProcessor::GetAttachmentService() const {
 704   return scoped_ptr<syncer::AttachmentService>(
 705       new syncer::AttachmentServiceProxy(attachment_service_proxy_));
 706 }
 707
 708 }  // namespace sync_driver