chrome/browser/sync_file_system/drive_backend/sync_worker.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 "chrome/browser/sync_file_system/drive_backend/sync_worker.h"
   6
   7 #include <vector>
   8
   9 #include "base/bind.h"
  10 #include "chrome/browser/extensions/extension_service.h"
  11 #include "chrome/browser/sync_file_system/drive_backend/callback_helper.h"
  12 #include "chrome/browser/sync_file_system/drive_backend/conflict_resolver.h"
  13 #include "chrome/browser/sync_file_system/drive_backend/drive_backend_constants.h"
  14 #include "chrome/browser/sync_file_system/drive_backend/list_changes_task.h"
  15 #include "chrome/browser/sync_file_system/drive_backend/local_to_remote_syncer.h"
  16 #include "chrome/browser/sync_file_system/drive_backend/metadata_database.h"
  17 #include "chrome/browser/sync_file_system/drive_backend/register_app_task.h"
  18 #include "chrome/browser/sync_file_system/drive_backend/remote_change_processor_on_worker.h"
  19 #include "chrome/browser/sync_file_system/drive_backend/remote_to_local_syncer.h"
  20 #include "chrome/browser/sync_file_system/drive_backend/sync_engine_context.h"
  21 #include "chrome/browser/sync_file_system/drive_backend/sync_engine_initializer.h"
  22 #include "chrome/browser/sync_file_system/drive_backend/sync_task.h"
  23 #include "chrome/browser/sync_file_system/drive_backend/uninstall_app_task.h"
  24 #include "chrome/browser/sync_file_system/logger.h"
  25 #include "chrome/browser/sync_file_system/syncable_file_system_util.h"
  26 #include "components/drive/service/drive_service_interface.h"
  27 #include "storage/common/fileapi/file_system_util.h"
  28
  29 namespace sync_file_system {
  30
  31 class RemoteChangeProcessor;
  32
  33 namespace drive_backend {
  34
  35 namespace {
  36
  37 void EmptyStatusCallback(SyncStatusCode status) {}
  38
  39 void InvokeIdleCallback(const base::Closure& idle_callback,
  40                         const SyncStatusCallback& callback) {
  41   idle_callback.Run();
  42   callback.Run(SYNC_STATUS_OK);
  43 }
  44
  45 }  // namespace
  46
  47 SyncWorker::SyncWorker(
  48     const base::FilePath& base_dir,
  49     const base::WeakPtr<ExtensionServiceInterface>& extension_service,
  50     leveldb::Env* env_override)
  51     : base_dir_(base_dir),
  52       env_override_(env_override),
  53       service_state_(REMOTE_SERVICE_TEMPORARY_UNAVAILABLE),
  54       should_check_conflict_(true),
  55       should_check_remote_change_(true),
  56       listing_remote_changes_(false),
  57       sync_enabled_(false),
  58       extension_service_(extension_service),
  59       weak_ptr_factory_(this) {
  60   sequence_checker_.DetachFromSequence();
  61   DCHECK(base_dir_.IsAbsolute());
  62 }
  63
  64 SyncWorker::~SyncWorker() {
  65   observers_.Clear();
  66 }
  67
  68 void SyncWorker::Initialize(scoped_ptr<SyncEngineContext> context) {
  69   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
  70   DCHECK(!task_manager_);
  71
  72   context_ = context.Pass();
  73
  74   task_manager_.reset(new SyncTaskManager(
  75       weak_ptr_factory_.GetWeakPtr(), 0 /* maximum_background_task */,
  76       context_->GetWorkerTaskRunner(),
  77       context_->GetWorkerPool()));
  78   task_manager_->Initialize(SYNC_STATUS_OK);
  79
  80   PostInitializeTask();
  81 }
  82
  83 void SyncWorker::RegisterOrigin(
  84     const GURL& origin,
  85     const SyncStatusCallback& callback) {
  86   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
  87
  88   if (!GetMetadataDatabase())
  89     PostInitializeTask();
  90
  91   scoped_ptr<RegisterAppTask> task(
  92       new RegisterAppTask(context_.get(), origin.host()));
  93   if (task->CanFinishImmediately()) {
  94     callback.Run(SYNC_STATUS_OK);
  95     return;
  96   }
  97
  98   task_manager_->ScheduleSyncTask(
  99       FROM_HERE, task.Pass(), SyncTaskManager::PRIORITY_HIGH, callback);
 100 }
 101
 102 void SyncWorker::EnableOrigin(
 103     const GURL& origin,
 104     const SyncStatusCallback& callback) {
 105   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
 106
 107   task_manager_->ScheduleTask(
 108       FROM_HERE,
 109       base::Bind(&SyncWorker::DoEnableApp,
 110                  weak_ptr_factory_.GetWeakPtr(),
 111                  origin.host()),
 112       SyncTaskManager::PRIORITY_HIGH,
 113       callback);
 114 }
 115
 116 void SyncWorker::DisableOrigin(
 117     const GURL& origin,
 118     const SyncStatusCallback& callback) {
 119   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
 120
 121   task_manager_->ScheduleTask(
 122       FROM_HERE,
 123       base::Bind(&SyncWorker::DoDisableApp,
 124                  weak_ptr_factory_.GetWeakPtr(),
 125                  origin.host()),
 126       SyncTaskManager::PRIORITY_HIGH,
 127       callback);
 128 }
 129
 130 void SyncWorker::UninstallOrigin(
 131     const GURL& origin,
 132     RemoteFileSyncService::UninstallFlag flag,
 133     const SyncStatusCallback& callback) {
 134   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
 135
 136   task_manager_->ScheduleSyncTask(
 137       FROM_HERE,
 138       scoped_ptr<SyncTask>(
 139           new UninstallAppTask(context_.get(), origin.host(), flag)),
 140       SyncTaskManager::PRIORITY_HIGH,
 141       callback);
 142 }
 143
 144 void SyncWorker::ProcessRemoteChange(const SyncFileCallback& callback) {
 145   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
 146
 147   RemoteToLocalSyncer* syncer = new RemoteToLocalSyncer(context_.get());
 148   task_manager_->ScheduleSyncTask(
 149       FROM_HERE,
 150       scoped_ptr<SyncTask>(syncer),
 151       SyncTaskManager::PRIORITY_MED,
 152       base::Bind(&SyncWorker::DidProcessRemoteChange,
 153                  weak_ptr_factory_.GetWeakPtr(),
 154                  syncer,
 155                  callback));
 156 }
 157
 158 void SyncWorker::SetRemoteChangeProcessor(
 159     RemoteChangeProcessorOnWorker* remote_change_processor_on_worker) {
 160   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
 161
 162   context_->SetRemoteChangeProcessor(remote_change_processor_on_worker);
 163 }
 164
 165 RemoteServiceState SyncWorker::GetCurrentState() const {
 166   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
 167
 168   if (!sync_enabled_)
 169     return REMOTE_SERVICE_DISABLED;
 170   return service_state_;
 171 }
 172
 173 void SyncWorker::GetOriginStatusMap(
 174     const RemoteFileSyncService::StatusMapCallback& callback) {
 175   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
 176
 177   if (!GetMetadataDatabase())
 178     return;
 179
 180   std::vector<std::string> app_ids;
 181   GetMetadataDatabase()->GetRegisteredAppIDs(&app_ids);
 182
 183   scoped_ptr<RemoteFileSyncService::OriginStatusMap>
 184       status_map(new RemoteFileSyncService::OriginStatusMap);
 185   for (std::vector<std::string>::const_iterator itr = app_ids.begin();
 186        itr != app_ids.end(); ++itr) {
 187     const std::string& app_id = *itr;
 188     GURL origin = extensions::Extension::GetBaseURLFromExtensionId(app_id);
 189     (*status_map)[origin] =
 190         GetMetadataDatabase()->IsAppEnabled(app_id) ? "Enabled" : "Disabled";
 191   }
 192
 193   callback.Run(status_map.Pass());
 194 }
 195
 196 scoped_ptr<base::ListValue> SyncWorker::DumpFiles(const GURL& origin) {
 197   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
 198
 199   if (!GetMetadataDatabase())
 200     return scoped_ptr<base::ListValue>();
 201   return GetMetadataDatabase()->DumpFiles(origin.host());
 202 }
 203
 204 scoped_ptr<base::ListValue> SyncWorker::DumpDatabase() {
 205   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
 206
 207   if (!GetMetadataDatabase())
 208     return scoped_ptr<base::ListValue>();
 209   return GetMetadataDatabase()->DumpDatabase();
 210 }
 211
 212 void SyncWorker::SetSyncEnabled(bool enabled) {
 213   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
 214
 215   if (sync_enabled_ == enabled)
 216     return;
 217
 218   RemoteServiceState old_state = GetCurrentState();
 219   sync_enabled_ = enabled;
 220   if (old_state == GetCurrentState())
 221     return;
 222
 223   FOR_EACH_OBSERVER(
 224       Observer,
 225       observers_,
 226       UpdateServiceState(
 227           GetCurrentState(),
 228           enabled ? "Sync is enabled" : "Sync is disabled"));
 229 }
 230
 231 void SyncWorker::PromoteDemotedChanges(const base::Closure& callback) {
 232   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
 233
 234   MetadataDatabase* metadata_db = GetMetadataDatabase();
 235   if (metadata_db && metadata_db->HasDemotedDirtyTracker()) {
 236     metadata_db->PromoteDemotedTrackers();
 237     FOR_EACH_OBSERVER(
 238         Observer,
 239         observers_,
 240         OnPendingFileListUpdated(metadata_db->CountDirtyTracker()));
 241   }
 242   callback.Run();
 243 }
 244
 245 void SyncWorker::ApplyLocalChange(const FileChange& local_change,
 246                                   const base::FilePath& local_path,
 247                                   const SyncFileMetadata& local_metadata,
 248                                   const storage::FileSystemURL& url,
 249                                   const SyncStatusCallback& callback) {
 250   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
 251
 252   LocalToRemoteSyncer* syncer = new LocalToRemoteSyncer(
 253       context_.get(), local_metadata, local_change, local_path, url);
 254   task_manager_->ScheduleSyncTask(
 255       FROM_HERE,
 256       scoped_ptr<SyncTask>(syncer),
 257       SyncTaskManager::PRIORITY_MED,
 258       base::Bind(&SyncWorker::DidApplyLocalChange,
 259                  weak_ptr_factory_.GetWeakPtr(),
 260                  syncer,
 261                  callback));
 262 }
 263
 264 void SyncWorker::MaybeScheduleNextTask() {
 265   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
 266
 267   if (GetCurrentState() == REMOTE_SERVICE_DISABLED)
 268     return;
 269
 270   // TODO(tzik): Notify observer of OnRemoteChangeQueueUpdated.
 271   // TODO(tzik): Add an interface to get the number of dirty trackers to
 272   // MetadataDatabase.
 273
 274   if (MaybeStartFetchChanges())
 275     return;
 276
 277   if (!call_on_idle_callback_.is_null()) {
 278     base::Closure callback = call_on_idle_callback_;
 279     call_on_idle_callback_.Reset();
 280     callback.Run();
 281   }
 282 }
 283
 284 void SyncWorker::NotifyLastOperationStatus(
 285     SyncStatusCode status,
 286     bool used_network) {
 287   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
 288
 289   UpdateServiceStateFromSyncStatusCode(status, used_network);
 290
 291   if (GetMetadataDatabase()) {
 292     FOR_EACH_OBSERVER(
 293         Observer, observers_,
 294         OnPendingFileListUpdated(GetMetadataDatabase()->CountDirtyTracker()));
 295   }
 296 }
 297
 298 void SyncWorker::RecordTaskLog(scoped_ptr<TaskLogger::TaskLog> task_log) {
 299   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
 300
 301   context_->GetUITaskRunner()->PostTask(
 302       FROM_HERE,
 303       base::Bind(&TaskLogger::RecordLog,
 304                  context_->GetTaskLogger(),
 305                  base::Passed(&task_log)));
 306 }
 307
 308 void SyncWorker::ActivateService(RemoteServiceState service_state,
 309                                  const std::string& description) {
 310   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
 311   UpdateServiceState(service_state, description);
 312   if (!GetMetadataDatabase()) {
 313     PostInitializeTask();
 314     return;
 315   }
 316
 317   should_check_remote_change_ = true;
 318   MaybeScheduleNextTask();
 319 }
 320
 321 void SyncWorker::DeactivateService(const std::string& description) {
 322   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
 323   UpdateServiceState(REMOTE_SERVICE_TEMPORARY_UNAVAILABLE, description);
 324 }
 325
 326 void SyncWorker::DetachFromSequence() {
 327   task_manager_->DetachFromSequence();
 328   context_->DetachFromSequence();
 329   sequence_checker_.DetachFromSequence();
 330 }
 331
 332 void SyncWorker::AddObserver(Observer* observer) {
 333   observers_.AddObserver(observer);
 334 }
 335
 336 void SyncWorker::DoDisableApp(const std::string& app_id,
 337                               const SyncStatusCallback& callback) {
 338   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
 339
 340   if (!GetMetadataDatabase()) {
 341     callback.Run(SYNC_STATUS_OK);
 342     return;
 343   }
 344
 345   SyncStatusCode status = GetMetadataDatabase()->DisableApp(app_id);
 346   callback.Run(status);
 347 }
 348
 349 void SyncWorker::DoEnableApp(const std::string& app_id,
 350                              const SyncStatusCallback& callback) {
 351   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
 352
 353   if (!GetMetadataDatabase()) {
 354     callback.Run(SYNC_STATUS_OK);
 355     return;
 356   }
 357
 358   SyncStatusCode status = GetMetadataDatabase()->EnableApp(app_id);
 359   callback.Run(status);
 360 }
 361
 362 void SyncWorker::PostInitializeTask() {
 363   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
 364   DCHECK(!GetMetadataDatabase());
 365
 366   // This initializer task may not run if MetadataDatabase in context_ is
 367   // already initialized when it runs.
 368   SyncEngineInitializer* initializer =
 369       new SyncEngineInitializer(context_.get(),
 370                                 base_dir_.Append(kDatabaseName),
 371                                 env_override_);
 372   task_manager_->ScheduleSyncTask(
 373       FROM_HERE,
 374       scoped_ptr<SyncTask>(initializer),
 375       SyncTaskManager::PRIORITY_HIGH,
 376       base::Bind(&SyncWorker::DidInitialize,
 377                  weak_ptr_factory_.GetWeakPtr(),
 378                  initializer));
 379 }
 380
 381 void SyncWorker::DidInitialize(SyncEngineInitializer* initializer,
 382                                SyncStatusCode status) {
 383   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
 384
 385   if (status == SYNC_STATUS_ACCESS_FORBIDDEN) {
 386     UpdateServiceState(REMOTE_SERVICE_ACCESS_FORBIDDEN, "Access forbidden");
 387     return;
 388   }
 389   if (status != SYNC_STATUS_OK) {
 390     UpdateServiceState(REMOTE_SERVICE_TEMPORARY_UNAVAILABLE,
 391                        "Could not initialize remote service");
 392     return;
 393   }
 394
 395   scoped_ptr<MetadataDatabase> metadata_database =
 396       initializer->PassMetadataDatabase();
 397   if (metadata_database) {
 398     context_->SetMetadataDatabase(metadata_database.Pass());
 399     return;
 400   }
 401
 402   UpdateServiceState(REMOTE_SERVICE_OK, std::string());
 403   UpdateRegisteredApps();
 404 }
 405
 406 void SyncWorker::UpdateRegisteredApps() {
 407   MetadataDatabase* metadata_db = GetMetadataDatabase();
 408   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
 409   DCHECK(metadata_db);
 410
 411   scoped_ptr<std::vector<std::string> > app_ids(new std::vector<std::string>);
 412   metadata_db->GetRegisteredAppIDs(app_ids.get());
 413
 414   AppStatusMap* app_status = new AppStatusMap;
 415   base::Closure callback =
 416       base::Bind(&SyncWorker::DidQueryAppStatus,
 417                  weak_ptr_factory_.GetWeakPtr(),
 418                  base::Owned(app_status));
 419
 420   context_->GetUITaskRunner()->PostTask(
 421       FROM_HERE,
 422       base::Bind(&SyncWorker::QueryAppStatusOnUIThread,
 423                  extension_service_,
 424                  base::Owned(app_ids.release()),
 425                  app_status,
 426                  RelayCallbackToTaskRunner(
 427                      context_->GetWorkerTaskRunner(),
 428                      FROM_HERE, callback)));
 429 }
 430
 431 void SyncWorker::QueryAppStatusOnUIThread(
 432     const base::WeakPtr<ExtensionServiceInterface>& extension_service_ptr,
 433     const std::vector<std::string>* app_ids,
 434     AppStatusMap* status,
 435     const base::Closure& callback) {
 436   ExtensionServiceInterface* extension_service = extension_service_ptr.get();
 437   if (!extension_service) {
 438     callback.Run();
 439     return;
 440   }
 441
 442   for (std::vector<std::string>::const_iterator itr = app_ids->begin();
 443        itr != app_ids->end(); ++itr) {
 444     const std::string& app_id = *itr;
 445     if (!extension_service->GetInstalledExtension(app_id))
 446       (*status)[app_id] = APP_STATUS_UNINSTALLED;
 447     else if (!extension_service->IsExtensionEnabled(app_id))
 448       (*status)[app_id] = APP_STATUS_DISABLED;
 449     else
 450       (*status)[app_id] = APP_STATUS_ENABLED;
 451   }
 452
 453   callback.Run();
 454 }
 455
 456 void SyncWorker::DidQueryAppStatus(const AppStatusMap* app_status) {
 457   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
 458
 459   MetadataDatabase* metadata_db = GetMetadataDatabase();
 460   DCHECK(metadata_db);
 461
 462   // Update the status of every origin using status from ExtensionService.
 463   for (AppStatusMap::const_iterator itr = app_status->begin();
 464        itr != app_status->end(); ++itr) {
 465     const std::string& app_id = itr->first;
 466     GURL origin = extensions::Extension::GetBaseURLFromExtensionId(app_id);
 467
 468     if (itr->second == APP_STATUS_UNINSTALLED) {
 469       // Extension has been uninstalled.
 470       // (At this stage we can't know if it was unpacked extension or not,
 471       // so just purge the remote folder.)
 472       UninstallOrigin(origin,
 473                       RemoteFileSyncService::UNINSTALL_AND_PURGE_REMOTE,
 474                       base::Bind(&EmptyStatusCallback));
 475       continue;
 476     }
 477
 478     FileTracker tracker;
 479     if (!metadata_db->FindAppRootTracker(app_id, &tracker)) {
 480       // App will register itself on first run.
 481       continue;
 482     }
 483
 484     DCHECK(itr->second == APP_STATUS_ENABLED ||
 485            itr->second == APP_STATUS_DISABLED);
 486     bool is_app_enabled = (itr->second == APP_STATUS_ENABLED);
 487     bool is_app_root_tracker_enabled =
 488         (tracker.tracker_kind() == TRACKER_KIND_APP_ROOT);
 489     if (is_app_enabled && !is_app_root_tracker_enabled)
 490       EnableOrigin(origin, base::Bind(&EmptyStatusCallback));
 491     else if (!is_app_enabled && is_app_root_tracker_enabled)
 492       DisableOrigin(origin, base::Bind(&EmptyStatusCallback));
 493   }
 494 }
 495
 496 void SyncWorker::DidProcessRemoteChange(RemoteToLocalSyncer* syncer,
 497                                         const SyncFileCallback& callback,
 498                                         SyncStatusCode status) {
 499   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
 500
 501   if (syncer->is_sync_root_deletion()) {
 502     MetadataDatabase::ClearDatabase(context_->PassMetadataDatabase());
 503     PostInitializeTask();
 504     callback.Run(status, syncer->url());
 505     return;
 506   }
 507
 508   if (status == SYNC_STATUS_OK) {
 509     if (syncer->sync_action() != SYNC_ACTION_NONE &&
 510         syncer->url().is_valid()) {
 511       FOR_EACH_OBSERVER(
 512           Observer, observers_,
 513           OnFileStatusChanged(
 514               syncer->url(),
 515               syncer->file_type(),
 516               SYNC_FILE_STATUS_SYNCED,
 517               syncer->sync_action(),
 518               SYNC_DIRECTION_REMOTE_TO_LOCAL));
 519     }
 520
 521     if (syncer->sync_action() == SYNC_ACTION_DELETED &&
 522         syncer->url().is_valid() &&
 523         storage::VirtualPath::IsRootPath(syncer->url().path())) {
 524       RegisterOrigin(syncer->url().origin(), base::Bind(&EmptyStatusCallback));
 525     }
 526     should_check_conflict_ = true;
 527   }
 528   callback.Run(status, syncer->url());
 529 }
 530
 531 void SyncWorker::DidApplyLocalChange(LocalToRemoteSyncer* syncer,
 532                                      const SyncStatusCallback& callback,
 533                                      SyncStatusCode status) {
 534   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
 535
 536   if ((status == SYNC_STATUS_OK || status == SYNC_STATUS_RETRY) &&
 537       syncer->url().is_valid() &&
 538       syncer->sync_action() != SYNC_ACTION_NONE) {
 539     storage::FileSystemURL updated_url = syncer->url();
 540     if (!syncer->target_path().empty()) {
 541       updated_url = CreateSyncableFileSystemURL(syncer->url().origin(),
 542                                                 syncer->target_path());
 543     }
 544     FOR_EACH_OBSERVER(Observer, observers_,
 545                       OnFileStatusChanged(updated_url,
 546                                           syncer->file_type(),
 547                                           SYNC_FILE_STATUS_SYNCED,
 548                                           syncer->sync_action(),
 549                                           SYNC_DIRECTION_LOCAL_TO_REMOTE));
 550   }
 551
 552   if (status == SYNC_STATUS_UNKNOWN_ORIGIN && syncer->url().is_valid()) {
 553     RegisterOrigin(syncer->url().origin(),
 554                    base::Bind(&EmptyStatusCallback));
 555   }
 556
 557   if (syncer->needs_remote_change_listing() &&
 558       !listing_remote_changes_) {
 559     task_manager_->ScheduleSyncTask(
 560         FROM_HERE,
 561         scoped_ptr<SyncTask>(new ListChangesTask(context_.get())),
 562         SyncTaskManager::PRIORITY_HIGH,
 563         base::Bind(&SyncWorker::DidFetchChanges,
 564                    weak_ptr_factory_.GetWeakPtr()));
 565     should_check_remote_change_ = false;
 566     listing_remote_changes_ = true;
 567     time_to_check_changes_ =
 568         base::TimeTicks::Now() +
 569         base::TimeDelta::FromSeconds(kListChangesRetryDelaySeconds);
 570   }
 571
 572   if (status == SYNC_STATUS_OK)
 573     should_check_conflict_ = true;
 574
 575   callback.Run(status);
 576 }
 577
 578 bool SyncWorker::MaybeStartFetchChanges() {
 579   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
 580
 581   if (GetCurrentState() == REMOTE_SERVICE_DISABLED)
 582     return false;
 583
 584   if (!GetMetadataDatabase())
 585     return false;
 586
 587   if (listing_remote_changes_)
 588     return false;
 589
 590   base::TimeTicks now = base::TimeTicks::Now();
 591   if (!should_check_remote_change_ && now < time_to_check_changes_) {
 592     if (!GetMetadataDatabase()->HasDirtyTracker() &&
 593         should_check_conflict_) {
 594       should_check_conflict_ = false;
 595       return task_manager_->ScheduleSyncTaskIfIdle(
 596           FROM_HERE,
 597           scoped_ptr<SyncTask>(new ConflictResolver(context_.get())),
 598           base::Bind(&SyncWorker::DidResolveConflict,
 599                      weak_ptr_factory_.GetWeakPtr()));
 600     }
 601     return false;
 602   }
 603
 604   if (task_manager_->ScheduleSyncTaskIfIdle(
 605           FROM_HERE,
 606           scoped_ptr<SyncTask>(new ListChangesTask(context_.get())),
 607           base::Bind(&SyncWorker::DidFetchChanges,
 608                      weak_ptr_factory_.GetWeakPtr()))) {
 609     should_check_remote_change_ = false;
 610     listing_remote_changes_ = true;
 611     time_to_check_changes_ =
 612         now + base::TimeDelta::FromSeconds(kListChangesRetryDelaySeconds);
 613     return true;
 614   }
 615   return false;
 616 }
 617
 618 void SyncWorker::DidResolveConflict(SyncStatusCode status) {
 619   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
 620
 621   if (status == SYNC_STATUS_OK || status == SYNC_STATUS_RETRY)
 622     should_check_conflict_ = true;
 623 }
 624
 625 void SyncWorker::DidFetchChanges(SyncStatusCode status) {
 626   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
 627
 628   if (status == SYNC_STATUS_OK)
 629     should_check_conflict_ = true;
 630   listing_remote_changes_ = false;
 631 }
 632
 633 void SyncWorker::UpdateServiceStateFromSyncStatusCode(
 634     SyncStatusCode status,
 635     bool used_network) {
 636   switch (status) {
 637     case SYNC_STATUS_OK:
 638       if (used_network)
 639         UpdateServiceState(REMOTE_SERVICE_OK, std::string());
 640       break;
 641
 642     // Authentication error.
 643     case SYNC_STATUS_AUTHENTICATION_FAILED:
 644       UpdateServiceState(REMOTE_SERVICE_AUTHENTICATION_REQUIRED,
 645                          "Authentication required");
 646       break;
 647
 648     // OAuth token error.
 649     case SYNC_STATUS_ACCESS_FORBIDDEN:
 650       UpdateServiceState(REMOTE_SERVICE_ACCESS_FORBIDDEN,
 651                          "Access forbidden");
 652       break;
 653
 654     // Errors which could make the service temporarily unavailable.
 655     case SYNC_STATUS_SERVICE_TEMPORARILY_UNAVAILABLE:
 656     case SYNC_STATUS_NETWORK_ERROR:
 657     case SYNC_STATUS_ABORT:
 658     case SYNC_STATUS_FAILED:
 659       UpdateServiceState(REMOTE_SERVICE_TEMPORARY_UNAVAILABLE,
 660                          "Network or temporary service error.");
 661       break;
 662
 663     // Errors which would require manual user intervention to resolve.
 664     case SYNC_DATABASE_ERROR_CORRUPTION:
 665     case SYNC_DATABASE_ERROR_IO_ERROR:
 666     case SYNC_DATABASE_ERROR_FAILED:
 667       UpdateServiceState(REMOTE_SERVICE_DISABLED,
 668                          "Unrecoverable database error");
 669       break;
 670
 671     default:
 672       // Other errors don't affect service state
 673       break;
 674   }
 675 }
 676
 677 void SyncWorker::UpdateServiceState(RemoteServiceState state,
 678                                     const std::string& description) {
 679   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
 680
 681   RemoteServiceState old_state = GetCurrentState();
 682   service_state_ = state;
 683
 684   if (old_state == GetCurrentState())
 685     return;
 686
 687   util::Log(logging::LOG_VERBOSE, FROM_HERE,
 688             "Service state changed: %d->%d: %s",
 689             old_state, GetCurrentState(), description.c_str());
 690
 691   FOR_EACH_OBSERVER(
 692       Observer, observers_,
 693       UpdateServiceState(GetCurrentState(), description));
 694 }
 695
 696 void SyncWorker::CallOnIdleForTesting(const base::Closure& callback) {
 697   if (task_manager_->ScheduleTaskIfIdle(
 698           FROM_HERE,
 699           base::Bind(&InvokeIdleCallback, callback),
 700           base::Bind(&EmptyStatusCallback)))
 701     return;
 702   call_on_idle_callback_ = base::Bind(
 703       &SyncWorker::CallOnIdleForTesting,
 704       weak_ptr_factory_.GetWeakPtr(),
 705       callback);
 706 }
 707
 708 drive::DriveServiceInterface* SyncWorker::GetDriveService() {
 709   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
 710   return context_->GetDriveService();
 711 }
 712
 713 drive::DriveUploaderInterface* SyncWorker::GetDriveUploader() {
 714   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
 715   return context_->GetDriveUploader();
 716 }
 717
 718 MetadataDatabase* SyncWorker::GetMetadataDatabase() {
 719   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
 720   return context_->GetMetadataDatabase();
 721 }
 722
 723 }  // namespace drive_backend
 724 }  // namespace sync_file_system