src/chrome/browser/sync_file_system/local/local_file_change_tracker.cc

   1 // Copyright 2013 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/local/local_file_change_tracker.h"
   6
   7 #include <queue>
   8
   9 #include "base/location.h"
  10 #include "base/logging.h"
  11 #include "base/sequenced_task_runner.h"
  12 #include "base/stl_util.h"
  13 #include "chrome/browser/sync_file_system/local/local_file_sync_status.h"
  14 #include "chrome/browser/sync_file_system/syncable_file_system_util.h"
  15 #include "storage/browser/fileapi/file_system_context.h"
  16 #include "storage/browser/fileapi/file_system_file_util.h"
  17 #include "storage/browser/fileapi/file_system_operation_context.h"
  18 #include "storage/common/fileapi/file_system_util.h"
  19 #include "third_party/leveldatabase/src/helpers/memenv/memenv.h"
  20 #include "third_party/leveldatabase/src/include/leveldb/db.h"
  21 #include "third_party/leveldatabase/src/include/leveldb/env.h"
  22 #include "third_party/leveldatabase/src/include/leveldb/write_batch.h"
  23
  24 using storage::FileSystemContext;
  25 using storage::FileSystemFileUtil;
  26 using storage::FileSystemOperationContext;
  27 using storage::FileSystemURL;
  28 using storage::FileSystemURLSet;
  29
  30 namespace sync_file_system {
  31
  32 namespace {
  33 const base::FilePath::CharType kDatabaseName[] =
  34     FILE_PATH_LITERAL("LocalFileChangeTracker");
  35 const char kMark[] = "d";
  36 }  // namespace
  37
  38 // A database class that stores local file changes in a local database. This
  39 // object must be destructed on file_task_runner.
  40 class LocalFileChangeTracker::TrackerDB {
  41  public:
  42   TrackerDB(const base::FilePath& base_path,
  43             leveldb::Env* env_override);
  44
  45   SyncStatusCode MarkDirty(const std::string& url);
  46   SyncStatusCode ClearDirty(const std::string& url);
  47   SyncStatusCode GetDirtyEntries(
  48       std::queue<FileSystemURL>* dirty_files);
  49   SyncStatusCode WriteBatch(scoped_ptr<leveldb::WriteBatch> batch);
  50
  51  private:
  52   enum RecoveryOption {
  53     REPAIR_ON_CORRUPTION,
  54     FAIL_ON_CORRUPTION,
  55   };
  56
  57   SyncStatusCode Init(RecoveryOption recovery_option);
  58   SyncStatusCode Repair(const std::string& db_path);
  59   void HandleError(const tracked_objects::Location& from_here,
  60                    const leveldb::Status& status);
  61
  62   const base::FilePath base_path_;
  63   leveldb::Env* env_override_;
  64   scoped_ptr<leveldb::DB> db_;
  65   SyncStatusCode db_status_;
  66
  67   DISALLOW_COPY_AND_ASSIGN(TrackerDB);
  68 };
  69
  70 LocalFileChangeTracker::ChangeInfo::ChangeInfo() : change_seq(-1) {}
  71 LocalFileChangeTracker::ChangeInfo::~ChangeInfo() {}
  72
  73 // LocalFileChangeTracker ------------------------------------------------------
  74
  75 LocalFileChangeTracker::LocalFileChangeTracker(
  76     const base::FilePath& base_path,
  77     leveldb::Env* env_override,
  78     base::SequencedTaskRunner* file_task_runner)
  79     : initialized_(false),
  80       file_task_runner_(file_task_runner),
  81       tracker_db_(new TrackerDB(base_path, env_override)),
  82       current_change_seq_number_(0),
  83       num_changes_(0) {
  84 }
  85
  86 LocalFileChangeTracker::~LocalFileChangeTracker() {
  87   DCHECK(file_task_runner_->RunsTasksOnCurrentThread());
  88   tracker_db_.reset();
  89 }
  90
  91 void LocalFileChangeTracker::OnStartUpdate(const FileSystemURL& url) {
  92   DCHECK(file_task_runner_->RunsTasksOnCurrentThread());
  93   if (ContainsKey(changes_, url) || ContainsKey(demoted_changes_, url))
  94     return;
  95   // TODO(nhiroki): propagate the error code (see http://crbug.com/152127).
  96   MarkDirtyOnDatabase(url);
  97 }
  98
  99 void LocalFileChangeTracker::OnEndUpdate(const FileSystemURL& url) {}
 100
 101 void LocalFileChangeTracker::OnCreateFile(const FileSystemURL& url) {
 102   RecordChange(url, FileChange(FileChange::FILE_CHANGE_ADD_OR_UPDATE,
 103                                SYNC_FILE_TYPE_FILE));
 104 }
 105
 106 void LocalFileChangeTracker::OnCreateFileFrom(const FileSystemURL& url,
 107                                               const FileSystemURL& src) {
 108   RecordChange(url, FileChange(FileChange::FILE_CHANGE_ADD_OR_UPDATE,
 109                                SYNC_FILE_TYPE_FILE));
 110 }
 111
 112 void LocalFileChangeTracker::OnRemoveFile(const FileSystemURL& url) {
 113   RecordChange(url, FileChange(FileChange::FILE_CHANGE_DELETE,
 114                                SYNC_FILE_TYPE_FILE));
 115 }
 116
 117 void LocalFileChangeTracker::OnModifyFile(const FileSystemURL& url) {
 118   RecordChange(url, FileChange(FileChange::FILE_CHANGE_ADD_OR_UPDATE,
 119                                SYNC_FILE_TYPE_FILE));
 120 }
 121
 122 void LocalFileChangeTracker::OnCreateDirectory(const FileSystemURL& url) {
 123   RecordChange(url, FileChange(FileChange::FILE_CHANGE_ADD_OR_UPDATE,
 124                                SYNC_FILE_TYPE_DIRECTORY));
 125 }
 126
 127 void LocalFileChangeTracker::OnRemoveDirectory(const FileSystemURL& url) {
 128   RecordChange(url, FileChange(FileChange::FILE_CHANGE_DELETE,
 129                                SYNC_FILE_TYPE_DIRECTORY));
 130 }
 131
 132 void LocalFileChangeTracker::GetNextChangedURLs(
 133     std::deque<FileSystemURL>* urls, int max_urls) {
 134   DCHECK(file_task_runner_->RunsTasksOnCurrentThread());
 135   DCHECK(urls);
 136   urls->clear();
 137   // Mildly prioritizes the URLs that older changes and have not been updated
 138   // for a while.
 139   for (ChangeSeqMap::iterator iter = change_seqs_.begin();
 140        iter != change_seqs_.end() &&
 141        (max_urls == 0 || urls->size() < static_cast<size_t>(max_urls));
 142        ++iter) {
 143     urls->push_back(iter->second);
 144   }
 145 }
 146
 147 void LocalFileChangeTracker::GetChangesForURL(
 148     const FileSystemURL& url, FileChangeList* changes) {
 149   DCHECK(file_task_runner_->RunsTasksOnCurrentThread());
 150   DCHECK(changes);
 151   changes->clear();
 152   FileChangeMap::iterator found = changes_.find(url);
 153   if (found == changes_.end()) {
 154     found = demoted_changes_.find(url);
 155     if (found == demoted_changes_.end())
 156       return;
 157   }
 158   *changes = found->second.change_list;
 159 }
 160
 161 void LocalFileChangeTracker::ClearChangesForURL(const FileSystemURL& url) {
 162   DCHECK(file_task_runner_->RunsTasksOnCurrentThread());
 163   ClearDirtyOnDatabase(url);
 164   mirror_changes_.erase(url);
 165   demoted_changes_.erase(url);
 166   FileChangeMap::iterator found = changes_.find(url);
 167   if (found == changes_.end())
 168     return;
 169   change_seqs_.erase(found->second.change_seq);
 170   changes_.erase(found);
 171   UpdateNumChanges();
 172 }
 173
 174 void LocalFileChangeTracker::CreateFreshMirrorForURL(
 175     const storage::FileSystemURL& url) {
 176   DCHECK(file_task_runner_->RunsTasksOnCurrentThread());
 177   DCHECK(!ContainsKey(mirror_changes_, url));
 178   mirror_changes_[url] = ChangeInfo();
 179 }
 180
 181 void LocalFileChangeTracker::RemoveMirrorAndCommitChangesForURL(
 182     const storage::FileSystemURL& url) {
 183   DCHECK(file_task_runner_->RunsTasksOnCurrentThread());
 184   FileChangeMap::iterator found = mirror_changes_.find(url);
 185   if (found == mirror_changes_.end())
 186     return;
 187   mirror_changes_.erase(found);
 188
 189   if (ContainsKey(changes_, url) || ContainsKey(demoted_changes_, url))
 190     MarkDirtyOnDatabase(url);
 191   else
 192     ClearDirtyOnDatabase(url);
 193   UpdateNumChanges();
 194 }
 195
 196 void LocalFileChangeTracker::ResetToMirrorAndCommitChangesForURL(
 197     const storage::FileSystemURL& url) {
 198   DCHECK(file_task_runner_->RunsTasksOnCurrentThread());
 199   FileChangeMap::iterator found = mirror_changes_.find(url);
 200   if (found == mirror_changes_.end() || found->second.change_list.empty()) {
 201     ClearChangesForURL(url);
 202     return;
 203   }
 204   const ChangeInfo& info = found->second;
 205   if (ContainsKey(demoted_changes_, url)) {
 206     DCHECK(!ContainsKey(changes_, url));
 207     demoted_changes_[url] = info;
 208   } else {
 209     DCHECK(!ContainsKey(demoted_changes_, url));
 210     change_seqs_[info.change_seq] = url;
 211     changes_[url] = info;
 212   }
 213   RemoveMirrorAndCommitChangesForURL(url);
 214 }
 215
 216 void LocalFileChangeTracker::DemoteChangesForURL(
 217     const storage::FileSystemURL& url) {
 218   DCHECK(file_task_runner_->RunsTasksOnCurrentThread());
 219
 220   FileChangeMap::iterator found = changes_.find(url);
 221   if (found == changes_.end())
 222     return;
 223   DCHECK(!ContainsKey(demoted_changes_, url));
 224   change_seqs_.erase(found->second.change_seq);
 225   demoted_changes_.insert(*found);
 226   changes_.erase(found);
 227   UpdateNumChanges();
 228 }
 229
 230 void LocalFileChangeTracker::PromoteDemotedChangesForURL(
 231     const storage::FileSystemURL& url) {
 232   DCHECK(file_task_runner_->RunsTasksOnCurrentThread());
 233
 234   FileChangeMap::iterator iter = demoted_changes_.find(url);
 235   if (iter == demoted_changes_.end())
 236     return;
 237
 238   FileChangeList::List change_list = iter->second.change_list.list();
 239   // Make sure that this URL is in no queues.
 240   DCHECK(!ContainsKey(change_seqs_, iter->second.change_seq));
 241   DCHECK(!ContainsKey(changes_, url));
 242
 243   change_seqs_[iter->second.change_seq] = url;
 244   changes_.insert(*iter);
 245   demoted_changes_.erase(iter);
 246   UpdateNumChanges();
 247 }
 248
 249 bool LocalFileChangeTracker::PromoteDemotedChanges() {
 250   DCHECK(file_task_runner_->RunsTasksOnCurrentThread());
 251   if (demoted_changes_.empty())
 252     return false;
 253   while (!demoted_changes_.empty()) {
 254     storage::FileSystemURL url = demoted_changes_.begin()->first;
 255     PromoteDemotedChangesForURL(url);
 256   }
 257   UpdateNumChanges();
 258   return true;
 259 }
 260
 261 SyncStatusCode LocalFileChangeTracker::Initialize(
 262     FileSystemContext* file_system_context) {
 263   DCHECK(file_task_runner_->RunsTasksOnCurrentThread());
 264   DCHECK(!initialized_);
 265   DCHECK(file_system_context);
 266
 267   SyncStatusCode status = CollectLastDirtyChanges(file_system_context);
 268   if (status == SYNC_STATUS_OK)
 269     initialized_ = true;
 270   return status;
 271 }
 272
 273 void LocalFileChangeTracker::ResetForFileSystem(const GURL& origin,
 274                                                 storage::FileSystemType type) {
 275   DCHECK(file_task_runner_->RunsTasksOnCurrentThread());
 276   scoped_ptr<leveldb::WriteBatch> batch(new leveldb::WriteBatch);
 277   for (FileChangeMap::iterator iter = changes_.begin();
 278        iter != changes_.end();) {
 279     storage::FileSystemURL url = iter->first;
 280     int change_seq = iter->second.change_seq;
 281     // Advance |iter| before calling ResetForURL to avoid the iterator
 282     // invalidation in it.
 283     ++iter;
 284     if (url.origin() == origin && url.type() == type)
 285       ResetForURL(url, change_seq, batch.get());
 286   }
 287
 288   for (FileChangeMap::iterator iter = demoted_changes_.begin();
 289        iter != demoted_changes_.end();) {
 290     storage::FileSystemURL url = iter->first;
 291     int change_seq = iter->second.change_seq;
 292     // Advance |iter| before calling ResetForURL to avoid the iterator
 293     // invalidation in it.
 294     ++iter;
 295     if (url.origin() == origin && url.type() == type)
 296       ResetForURL(url, change_seq, batch.get());
 297   }
 298
 299   // Fail to apply batch to database wouldn't have critical effect, they'll be
 300   // just marked deleted on next relaunch.
 301   tracker_db_->WriteBatch(batch.Pass());
 302   UpdateNumChanges();
 303 }
 304
 305 void LocalFileChangeTracker::UpdateNumChanges() {
 306   base::AutoLock lock(num_changes_lock_);
 307   num_changes_ = static_cast<int64>(change_seqs_.size());
 308 }
 309
 310 void LocalFileChangeTracker::GetAllChangedURLs(FileSystemURLSet* urls) {
 311   DCHECK(file_task_runner_->RunsTasksOnCurrentThread());
 312   std::deque<FileSystemURL> url_deque;
 313   GetNextChangedURLs(&url_deque, 0);
 314   urls->clear();
 315   urls->insert(url_deque.begin(), url_deque.end());
 316 }
 317
 318 void LocalFileChangeTracker::DropAllChanges() {
 319   DCHECK(file_task_runner_->RunsTasksOnCurrentThread());
 320   changes_.clear();
 321   change_seqs_.clear();
 322   mirror_changes_.clear();
 323   UpdateNumChanges();
 324 }
 325
 326 SyncStatusCode LocalFileChangeTracker::MarkDirtyOnDatabase(
 327     const FileSystemURL& url) {
 328   std::string serialized_url;
 329   if (!SerializeSyncableFileSystemURL(url, &serialized_url))
 330     return SYNC_FILE_ERROR_INVALID_URL;
 331
 332   return tracker_db_->MarkDirty(serialized_url);
 333 }
 334
 335 SyncStatusCode LocalFileChangeTracker::ClearDirtyOnDatabase(
 336     const FileSystemURL& url) {
 337   DCHECK(file_task_runner_->RunsTasksOnCurrentThread());
 338   std::string serialized_url;
 339   if (!SerializeSyncableFileSystemURL(url, &serialized_url))
 340     return SYNC_FILE_ERROR_INVALID_URL;
 341
 342   return tracker_db_->ClearDirty(serialized_url);
 343 }
 344
 345 SyncStatusCode LocalFileChangeTracker::CollectLastDirtyChanges(
 346     FileSystemContext* file_system_context) {
 347   DCHECK(file_task_runner_->RunsTasksOnCurrentThread());
 348
 349   std::queue<FileSystemURL> dirty_files;
 350   const SyncStatusCode status = tracker_db_->GetDirtyEntries(&dirty_files);
 351   if (status != SYNC_STATUS_OK)
 352     return status;
 353
 354   FileSystemFileUtil* file_util =
 355       file_system_context->sandbox_delegate()->sync_file_util();
 356   DCHECK(file_util);
 357   scoped_ptr<FileSystemOperationContext> context(
 358       new FileSystemOperationContext(file_system_context));
 359
 360   base::File::Info file_info;
 361   base::FilePath platform_path;
 362
 363   while (!dirty_files.empty()) {
 364     const FileSystemURL url = dirty_files.front();
 365     dirty_files.pop();
 366     DCHECK_EQ(url.type(), storage::kFileSystemTypeSyncable);
 367
 368     switch (file_util->GetFileInfo(context.get(), url,
 369                                    &file_info, &platform_path)) {
 370       case base::File::FILE_OK: {
 371         if (!file_info.is_directory) {
 372           RecordChange(url, FileChange(FileChange::FILE_CHANGE_ADD_OR_UPDATE,
 373                                        SYNC_FILE_TYPE_FILE));
 374           break;
 375         }
 376
 377         RecordChange(url, FileChange(
 378             FileChange::FILE_CHANGE_ADD_OR_UPDATE,
 379             SYNC_FILE_TYPE_DIRECTORY));
 380
 381         // Push files and directories in this directory into |dirty_files|.
 382         scoped_ptr<FileSystemFileUtil::AbstractFileEnumerator> enumerator(
 383             file_util->CreateFileEnumerator(context.get(), url));
 384         base::FilePath path_each;
 385         while (!(path_each = enumerator->Next()).empty()) {
 386           dirty_files.push(CreateSyncableFileSystemURL(
 387                   url.origin(), path_each));
 388         }
 389         break;
 390       }
 391       case base::File::FILE_ERROR_NOT_FOUND: {
 392         // File represented by |url| has already been deleted. Since we cannot
 393         // figure out if this file was directory or not from the URL, file
 394         // type is treated as SYNC_FILE_TYPE_UNKNOWN.
 395         //
 396         // NOTE: Directory to have been reverted (that is, ADD -> DELETE) is
 397         // also treated as FILE_CHANGE_DELETE.
 398         RecordChange(url, FileChange(FileChange::FILE_CHANGE_DELETE,
 399                                      SYNC_FILE_TYPE_UNKNOWN));
 400         break;
 401       }
 402       case base::File::FILE_ERROR_FAILED:
 403       default:
 404         // TODO(nhiroki): handle file access error (http://crbug.com/155251).
 405         LOG(WARNING) << "Failed to access local file.";
 406         break;
 407     }
 408   }
 409   return SYNC_STATUS_OK;
 410 }
 411
 412 void LocalFileChangeTracker::RecordChange(
 413     const FileSystemURL& url, const FileChange& change) {
 414   DCHECK(file_task_runner_->RunsTasksOnCurrentThread());
 415   int change_seq = current_change_seq_number_++;
 416   if (ContainsKey(demoted_changes_, url)) {
 417     RecordChangeToChangeMaps(url, change, change_seq,
 418                              &demoted_changes_, nullptr);
 419   } else {
 420     RecordChangeToChangeMaps(url, change, change_seq, &changes_, &change_seqs_);
 421   }
 422   if (ContainsKey(mirror_changes_, url)) {
 423     RecordChangeToChangeMaps(url, change, change_seq, &mirror_changes_,
 424                              nullptr);
 425   }
 426   UpdateNumChanges();
 427 }
 428
 429 // static
 430 void LocalFileChangeTracker::RecordChangeToChangeMaps(
 431     const FileSystemURL& url,
 432     const FileChange& change,
 433     int new_change_seq,
 434     FileChangeMap* changes,
 435     ChangeSeqMap* change_seqs) {
 436   ChangeInfo& info = (*changes)[url];
 437   if (info.change_seq >= 0 && change_seqs)
 438     change_seqs->erase(info.change_seq);
 439   info.change_list.Update(change);
 440   if (info.change_list.empty()) {
 441     changes->erase(url);
 442     return;
 443   }
 444   info.change_seq = new_change_seq;
 445   if (change_seqs)
 446     (*change_seqs)[info.change_seq] = url;
 447 }
 448
 449 void LocalFileChangeTracker::ResetForURL(const storage::FileSystemURL& url,
 450                                          int change_seq,
 451                                          leveldb::WriteBatch* batch) {
 452   mirror_changes_.erase(url);
 453   demoted_changes_.erase(url);
 454   change_seqs_.erase(change_seq);
 455   changes_.erase(url);
 456
 457   std::string serialized_url;
 458   if (!SerializeSyncableFileSystemURL(url, &serialized_url)) {
 459     NOTREACHED() << "Failed to serialize: " << url.DebugString();
 460     return;
 461   }
 462   batch->Delete(serialized_url);
 463 }
 464
 465 // TrackerDB -------------------------------------------------------------------
 466
 467 LocalFileChangeTracker::TrackerDB::TrackerDB(const base::FilePath& base_path,
 468                                              leveldb::Env* env_override)
 469   : base_path_(base_path),
 470     env_override_(env_override),
 471     db_status_(SYNC_STATUS_OK) {}
 472
 473 SyncStatusCode LocalFileChangeTracker::TrackerDB::Init(
 474     RecoveryOption recovery_option) {
 475   if (db_.get() && db_status_ == SYNC_STATUS_OK)
 476     return SYNC_STATUS_OK;
 477
 478   std::string path =
 479       storage::FilePathToString(base_path_.Append(kDatabaseName));
 480   leveldb::Options options;
 481   options.max_open_files = 0;  // Use minimum.
 482   options.create_if_missing = true;
 483   if (env_override_)
 484     options.env = env_override_;
 485   leveldb::DB* db;
 486   leveldb::Status status = leveldb::DB::Open(options, path, &db);
 487   if (status.ok()) {
 488     db_.reset(db);
 489     return SYNC_STATUS_OK;
 490   }
 491
 492   HandleError(FROM_HERE, status);
 493   if (!status.IsCorruption())
 494     return LevelDBStatusToSyncStatusCode(status);
 495
 496   // Try to repair the corrupted DB.
 497   switch (recovery_option) {
 498     case FAIL_ON_CORRUPTION:
 499       return SYNC_DATABASE_ERROR_CORRUPTION;
 500     case REPAIR_ON_CORRUPTION:
 501       return Repair(path);
 502   }
 503   NOTREACHED();
 504   return SYNC_DATABASE_ERROR_FAILED;
 505 }
 506
 507 SyncStatusCode LocalFileChangeTracker::TrackerDB::Repair(
 508     const std::string& db_path) {
 509   DCHECK(!db_.get());
 510   LOG(WARNING) << "Attempting to repair TrackerDB.";
 511
 512   leveldb::Options options;
 513   options.max_open_files = 0;  // Use minimum.
 514   if (leveldb::RepairDB(db_path, options).ok() &&
 515       Init(FAIL_ON_CORRUPTION) == SYNC_STATUS_OK) {
 516     // TODO(nhiroki): perform some consistency checks between TrackerDB and
 517     // syncable file system.
 518     LOG(WARNING) << "Repairing TrackerDB completed.";
 519     return SYNC_STATUS_OK;
 520   }
 521
 522   LOG(WARNING) << "Failed to repair TrackerDB.";
 523   return SYNC_DATABASE_ERROR_CORRUPTION;
 524 }
 525
 526 // TODO(nhiroki): factor out the common methods into somewhere else.
 527 void LocalFileChangeTracker::TrackerDB::HandleError(
 528     const tracked_objects::Location& from_here,
 529     const leveldb::Status& status) {
 530   LOG(ERROR) << "LocalFileChangeTracker::TrackerDB failed at: "
 531              << from_here.ToString() << " with error: " << status.ToString();
 532 }
 533
 534 SyncStatusCode LocalFileChangeTracker::TrackerDB::MarkDirty(
 535     const std::string& url) {
 536   if (db_status_ != SYNC_STATUS_OK)
 537     return db_status_;
 538
 539   db_status_ = Init(REPAIR_ON_CORRUPTION);
 540   if (db_status_ != SYNC_STATUS_OK) {
 541     db_.reset();
 542     return db_status_;
 543   }
 544
 545   leveldb::Status status = db_->Put(leveldb::WriteOptions(), url, kMark);
 546   if (!status.ok()) {
 547     HandleError(FROM_HERE, status);
 548     db_status_ = LevelDBStatusToSyncStatusCode(status);
 549     db_.reset();
 550     return db_status_;
 551   }
 552   return SYNC_STATUS_OK;
 553 }
 554
 555 SyncStatusCode LocalFileChangeTracker::TrackerDB::ClearDirty(
 556     const std::string& url) {
 557   if (db_status_ != SYNC_STATUS_OK)
 558     return db_status_;
 559
 560   // Should not reach here before initializing the database. The database should
 561   // be cleared after read, and should be initialized during read if
 562   // uninitialized.
 563   DCHECK(db_.get());
 564
 565   leveldb::Status status = db_->Delete(leveldb::WriteOptions(), url);
 566   if (!status.ok() && !status.IsNotFound()) {
 567     HandleError(FROM_HERE, status);
 568     db_status_ = LevelDBStatusToSyncStatusCode(status);
 569     db_.reset();
 570     return db_status_;
 571   }
 572   return SYNC_STATUS_OK;
 573 }
 574
 575 SyncStatusCode LocalFileChangeTracker::TrackerDB::GetDirtyEntries(
 576     std::queue<FileSystemURL>* dirty_files) {
 577   if (db_status_ != SYNC_STATUS_OK)
 578     return db_status_;
 579
 580   db_status_ = Init(REPAIR_ON_CORRUPTION);
 581   if (db_status_ != SYNC_STATUS_OK) {
 582     db_.reset();
 583     return db_status_;
 584   }
 585
 586   scoped_ptr<leveldb::Iterator> iter(db_->NewIterator(leveldb::ReadOptions()));
 587   iter->SeekToFirst();
 588   FileSystemURL url;
 589   while (iter->Valid()) {
 590     if (!DeserializeSyncableFileSystemURL(iter->key().ToString(), &url)) {
 591       LOG(WARNING) << "Failed to deserialize an URL. "
 592                    << "TrackerDB might be corrupted.";
 593       db_status_ = SYNC_DATABASE_ERROR_CORRUPTION;
 594       db_.reset();
 595       return db_status_;
 596     }
 597     dirty_files->push(url);
 598     iter->Next();
 599   }
 600   return SYNC_STATUS_OK;
 601 }
 602
 603 SyncStatusCode LocalFileChangeTracker::TrackerDB::WriteBatch(
 604     scoped_ptr<leveldb::WriteBatch> batch) {
 605   if (db_status_ != SYNC_STATUS_OK)
 606     return db_status_;
 607
 608   leveldb::Status status = db_->Write(leveldb::WriteOptions(), batch.get());
 609   if (!status.ok() && !status.IsNotFound()) {
 610     HandleError(FROM_HERE, status);
 611     db_status_ = LevelDBStatusToSyncStatusCode(status);
 612     db_.reset();
 613     return db_status_;
 614   }
 615   return SYNC_STATUS_OK;
 616 }
 617
 618 }  // namespace sync_file_system