content/browser/appcache/appcache_storage_impl.cc

   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 "content/browser/appcache/appcache_storage_impl.h"
   6
   7 #include <algorithm>
   8 #include <functional>
   9 #include <set>
  10 #include <vector>
  11
  12 #include "base/bind.h"
  13 #include "base/bind_helpers.h"
  14 #include "base/file_util.h"
  15 #include "base/logging.h"
  16 #include "base/message_loop/message_loop.h"
  17 #include "base/single_thread_task_runner.h"
  18 #include "base/stl_util.h"
  19 #include "base/strings/string_util.h"
  20 #include "content/browser/appcache/appcache.h"
  21 #include "content/browser/appcache/appcache_database.h"
  22 #include "content/browser/appcache/appcache_entry.h"
  23 #include "content/browser/appcache/appcache_group.h"
  24 #include "content/browser/appcache/appcache_histograms.h"
  25 #include "content/browser/appcache/appcache_quota_client.h"
  26 #include "content/browser/appcache/appcache_response.h"
  27 #include "content/browser/appcache/appcache_service_impl.h"
  28 #include "net/base/cache_type.h"
  29 #include "net/base/net_errors.h"
  30 #include "sql/connection.h"
  31 #include "sql/transaction.h"
  32 #include "webkit/browser/quota/quota_client.h"
  33 #include "webkit/browser/quota/quota_manager.h"
  34 #include "webkit/browser/quota/quota_manager_proxy.h"
  35 #include "webkit/browser/quota/special_storage_policy.h"
  36
  37 namespace content {
  38
  39 // Hard coded default when not using quota management.
  40 static const int kDefaultQuota = 5 * 1024 * 1024;
  41
  42 static const int kMaxDiskCacheSize = 250 * 1024 * 1024;
  43 static const int kMaxMemDiskCacheSize = 10 * 1024 * 1024;
  44 static const base::FilePath::CharType kDiskCacheDirectoryName[] =
  45     FILE_PATH_LITERAL("Cache");
  46
  47 namespace {
  48
  49 // Helpers for clearing data from the AppCacheDatabase.
  50 bool DeleteGroupAndRelatedRecords(AppCacheDatabase* database,
  51                                   int64 group_id,
  52                                   std::vector<int64>* deletable_response_ids) {
  53   AppCacheDatabase::CacheRecord cache_record;
  54   bool success = false;
  55   if (database->FindCacheForGroup(group_id, &cache_record)) {
  56     database->FindResponseIdsForCacheAsVector(cache_record.cache_id,
  57                                               deletable_response_ids);
  58     success =
  59         database->DeleteGroup(group_id) &&
  60         database->DeleteCache(cache_record.cache_id) &&
  61         database->DeleteEntriesForCache(cache_record.cache_id) &&
  62         database->DeleteNamespacesForCache(cache_record.cache_id) &&
  63         database->DeleteOnlineWhiteListForCache(cache_record.cache_id) &&
  64         database->InsertDeletableResponseIds(*deletable_response_ids);
  65   } else {
  66     NOTREACHED() << "A existing group without a cache is unexpected";
  67     success = database->DeleteGroup(group_id);
  68   }
  69   return success;
  70 }
  71
  72 // Destroys |database|. If there is appcache data to be deleted
  73 // (|force_keep_session_state| is false), deletes session-only appcache data.
  74 void ClearSessionOnlyOrigins(
  75     AppCacheDatabase* database,
  76     scoped_refptr<storage::SpecialStoragePolicy> special_storage_policy,
  77     bool force_keep_session_state) {
  78   scoped_ptr<AppCacheDatabase> database_to_delete(database);
  79
  80   // If saving session state, only delete the database.
  81   if (force_keep_session_state)
  82     return;
  83
  84   bool has_session_only_appcaches =
  85       special_storage_policy.get() &&
  86       special_storage_policy->HasSessionOnlyOrigins();
  87
  88   // Clearning only session-only databases, and there are none.
  89   if (!has_session_only_appcaches)
  90     return;
  91
  92   std::set<GURL> origins;
  93   database->FindOriginsWithGroups(&origins);
  94   if (origins.empty())
  95     return;  // nothing to delete
  96
  97   sql::Connection* connection = database->db_connection();
  98   if (!connection) {
  99     NOTREACHED() << "Missing database connection.";
 100     return;
 101   }
 102
 103   std::set<GURL>::const_iterator origin;
 104   DCHECK(special_storage_policy.get());
 105   for (origin = origins.begin(); origin != origins.end(); ++origin) {
 106     if (!special_storage_policy->IsStorageSessionOnly(*origin))
 107       continue;
 108     if (special_storage_policy->IsStorageProtected(*origin))
 109       continue;
 110
 111     std::vector<AppCacheDatabase::GroupRecord> groups;
 112     database->FindGroupsForOrigin(*origin, &groups);
 113     std::vector<AppCacheDatabase::GroupRecord>::const_iterator group;
 114     for (group = groups.begin(); group != groups.end(); ++group) {
 115       sql::Transaction transaction(connection);
 116       if (!transaction.Begin()) {
 117         NOTREACHED() << "Failed to start transaction";
 118         return;
 119       }
 120       std::vector<int64> deletable_response_ids;
 121       bool success = DeleteGroupAndRelatedRecords(database,
 122                                                   group->group_id,
 123                                                   &deletable_response_ids);
 124       success = success && transaction.Commit();
 125       DCHECK(success);
 126     }  // for each group
 127   }  // for each origin
 128 }
 129
 130 }  // namespace
 131
 132 // DatabaseTask -----------------------------------------
 133
 134 class AppCacheStorageImpl::DatabaseTask
 135     : public base::RefCountedThreadSafe<DatabaseTask> {
 136  public:
 137   explicit DatabaseTask(AppCacheStorageImpl* storage)
 138       : storage_(storage), database_(storage->database_),
 139         io_thread_(base::MessageLoopProxy::current()) {
 140     DCHECK(io_thread_.get());
 141   }
 142
 143   void AddDelegate(DelegateReference* delegate_reference) {
 144     delegates_.push_back(make_scoped_refptr(delegate_reference));
 145   }
 146
 147   // Schedules a task to be Run() on the DB thread. Tasks
 148   // are run in the order in which they are scheduled.
 149   void Schedule();
 150
 151   // Called on the DB thread.
 152   virtual void Run() = 0;
 153
 154   // Called on the IO thread after Run() has completed.
 155   virtual void RunCompleted() {}
 156
 157   // Once scheduled a task cannot be cancelled, but the
 158   // call to RunCompleted may be. This method should only be
 159   // called on the IO thread. This is used by AppCacheStorageImpl
 160   // to cancel the completion calls when AppCacheStorageImpl is
 161   // destructed. This method may be overriden to release or delete
 162   // additional data associated with the task that is not DB thread
 163   // safe. If overriden, this base class method must be called from
 164   // within the override.
 165   virtual void CancelCompletion();
 166
 167  protected:
 168   friend class base::RefCountedThreadSafe<DatabaseTask>;
 169   virtual ~DatabaseTask() {}
 170
 171   AppCacheStorageImpl* storage_;
 172   AppCacheDatabase* database_;
 173   DelegateReferenceVector delegates_;
 174
 175  private:
 176   void CallRun(base::TimeTicks schedule_time);
 177   void CallRunCompleted(base::TimeTicks schedule_time);
 178   void OnFatalError();
 179
 180   scoped_refptr<base::MessageLoopProxy> io_thread_;
 181 };
 182
 183 void AppCacheStorageImpl::DatabaseTask::Schedule() {
 184   DCHECK(storage_);
 185   DCHECK(io_thread_->BelongsToCurrentThread());
 186   if (!storage_->database_)
 187     return;
 188
 189   if (storage_->db_thread_->PostTask(
 190           FROM_HERE,
 191           base::Bind(&DatabaseTask::CallRun, this, base::TimeTicks::Now()))) {
 192     storage_->scheduled_database_tasks_.push_back(this);
 193   } else {
 194     NOTREACHED() << "Thread for database tasks is not running.";
 195   }
 196 }
 197
 198 void AppCacheStorageImpl::DatabaseTask::CancelCompletion() {
 199   DCHECK(io_thread_->BelongsToCurrentThread());
 200   delegates_.clear();
 201   storage_ = NULL;
 202 }
 203
 204 void AppCacheStorageImpl::DatabaseTask::CallRun(
 205     base::TimeTicks schedule_time) {
 206   AppCacheHistograms::AddTaskQueueTimeSample(
 207       base::TimeTicks::Now() - schedule_time);
 208   if (!database_->is_disabled()) {
 209     base::TimeTicks run_time = base::TimeTicks::Now();
 210     Run();
 211     AppCacheHistograms::AddTaskRunTimeSample(
 212         base::TimeTicks::Now() - run_time);
 213
 214     if (database_->was_corruption_detected()) {
 215       AppCacheHistograms::CountCorruptionDetected();
 216       database_->Disable();
 217     }
 218     if (database_->is_disabled()) {
 219       io_thread_->PostTask(
 220           FROM_HERE,
 221           base::Bind(&DatabaseTask::OnFatalError, this));
 222     }
 223   }
 224   io_thread_->PostTask(
 225       FROM_HERE,
 226       base::Bind(&DatabaseTask::CallRunCompleted, this,
 227                  base::TimeTicks::Now()));
 228 }
 229
 230 void AppCacheStorageImpl::DatabaseTask::CallRunCompleted(
 231     base::TimeTicks schedule_time) {
 232   AppCacheHistograms::AddCompletionQueueTimeSample(
 233       base::TimeTicks::Now() - schedule_time);
 234   if (storage_) {
 235     DCHECK(io_thread_->BelongsToCurrentThread());
 236     DCHECK(storage_->scheduled_database_tasks_.front() == this);
 237     storage_->scheduled_database_tasks_.pop_front();
 238     base::TimeTicks run_time = base::TimeTicks::Now();
 239     RunCompleted();
 240     AppCacheHistograms::AddCompletionRunTimeSample(
 241         base::TimeTicks::Now() - run_time);
 242     delegates_.clear();
 243   }
 244 }
 245
 246 void AppCacheStorageImpl::DatabaseTask::OnFatalError() {
 247   if (storage_) {
 248     DCHECK(io_thread_->BelongsToCurrentThread());
 249     storage_->Disable();
 250     storage_->DeleteAndStartOver();
 251   }
 252 }
 253
 254 // InitTask -------
 255
 256 class AppCacheStorageImpl::InitTask : public DatabaseTask {
 257  public:
 258   explicit InitTask(AppCacheStorageImpl* storage)
 259       : DatabaseTask(storage), last_group_id_(0),
 260         last_cache_id_(0), last_response_id_(0),
 261         last_deletable_response_rowid_(0) {
 262     if (!storage->is_incognito_) {
 263       db_file_path_ =
 264           storage->cache_directory_.Append(kAppCacheDatabaseName);
 265       disk_cache_directory_ =
 266           storage->cache_directory_.Append(kDiskCacheDirectoryName);
 267     }
 268   }
 269
 270   // DatabaseTask:
 271   virtual void Run() OVERRIDE;
 272   virtual void RunCompleted() OVERRIDE;
 273
 274  protected:
 275   virtual ~InitTask() {}
 276
 277  private:
 278   base::FilePath db_file_path_;
 279   base::FilePath disk_cache_directory_;
 280   int64 last_group_id_;
 281   int64 last_cache_id_;
 282   int64 last_response_id_;
 283   int64 last_deletable_response_rowid_;
 284   std::map<GURL, int64> usage_map_;
 285 };
 286
 287 void AppCacheStorageImpl::InitTask::Run() {
 288   // If there is no sql database, ensure there is no disk cache either.
 289   if (!db_file_path_.empty() &&
 290       !base::PathExists(db_file_path_) &&
 291       base::DirectoryExists(disk_cache_directory_)) {
 292     base::DeleteFile(disk_cache_directory_, true);
 293     if (base::DirectoryExists(disk_cache_directory_)) {
 294       database_->Disable();  // This triggers OnFatalError handling.
 295       return;
 296     }
 297   }
 298
 299   database_->FindLastStorageIds(
 300       &last_group_id_, &last_cache_id_, &last_response_id_,
 301       &last_deletable_response_rowid_);
 302   database_->GetAllOriginUsage(&usage_map_);
 303 }
 304
 305 void AppCacheStorageImpl::InitTask::RunCompleted() {
 306   storage_->last_group_id_ = last_group_id_;
 307   storage_->last_cache_id_ = last_cache_id_;
 308   storage_->last_response_id_ = last_response_id_;
 309   storage_->last_deletable_response_rowid_ = last_deletable_response_rowid_;
 310
 311   if (!storage_->is_disabled()) {
 312     storage_->usage_map_.swap(usage_map_);
 313     const base::TimeDelta kDelay = base::TimeDelta::FromMinutes(5);
 314     base::MessageLoop::current()->PostDelayedTask(
 315         FROM_HERE,
 316         base::Bind(&AppCacheStorageImpl::DelayedStartDeletingUnusedResponses,
 317                    storage_->weak_factory_.GetWeakPtr()),
 318         kDelay);
 319   }
 320
 321   if (storage_->service()->quota_client())
 322     storage_->service()->quota_client()->NotifyAppCacheReady();
 323 }
 324
 325 // DisableDatabaseTask -------
 326
 327 class AppCacheStorageImpl::DisableDatabaseTask : public DatabaseTask {
 328  public:
 329   explicit DisableDatabaseTask(AppCacheStorageImpl* storage)
 330       : DatabaseTask(storage) {}
 331
 332   // DatabaseTask:
 333   virtual void Run() OVERRIDE { database_->Disable(); }
 334
 335  protected:
 336   virtual ~DisableDatabaseTask() {}
 337 };
 338
 339 // GetAllInfoTask -------
 340
 341 class AppCacheStorageImpl::GetAllInfoTask : public DatabaseTask {
 342  public:
 343   explicit GetAllInfoTask(AppCacheStorageImpl* storage)
 344       : DatabaseTask(storage),
 345         info_collection_(new AppCacheInfoCollection()) {
 346   }
 347
 348   // DatabaseTask:
 349   virtual void Run() OVERRIDE;
 350   virtual void RunCompleted() OVERRIDE;
 351
 352  protected:
 353   virtual ~GetAllInfoTask() {}
 354
 355  private:
 356   scoped_refptr<AppCacheInfoCollection> info_collection_;
 357 };
 358
 359 void AppCacheStorageImpl::GetAllInfoTask::Run() {
 360   std::set<GURL> origins;
 361   database_->FindOriginsWithGroups(&origins);
 362   for (std::set<GURL>::const_iterator origin = origins.begin();
 363        origin != origins.end(); ++origin) {
 364     AppCacheInfoVector& infos =
 365         info_collection_->infos_by_origin[*origin];
 366     std::vector<AppCacheDatabase::GroupRecord> groups;
 367     database_->FindGroupsForOrigin(*origin, &groups);
 368     for (std::vector<AppCacheDatabase::GroupRecord>::const_iterator
 369          group = groups.begin();
 370          group != groups.end(); ++group) {
 371       AppCacheDatabase::CacheRecord cache_record;
 372       database_->FindCacheForGroup(group->group_id, &cache_record);
 373       AppCacheInfo info;
 374       info.manifest_url = group->manifest_url;
 375       info.creation_time = group->creation_time;
 376       info.size = cache_record.cache_size;
 377       info.last_access_time = group->last_access_time;
 378       info.last_update_time = cache_record.update_time;
 379       info.cache_id = cache_record.cache_id;
 380       info.group_id = group->group_id;
 381       info.is_complete = true;
 382       infos.push_back(info);
 383     }
 384   }
 385 }
 386
 387 void AppCacheStorageImpl::GetAllInfoTask::RunCompleted() {
 388   DCHECK_EQ(1U, delegates_.size());
 389   FOR_EACH_DELEGATE(delegates_, OnAllInfo(info_collection_.get()));
 390 }
 391
 392 // StoreOrLoadTask -------
 393
 394 class AppCacheStorageImpl::StoreOrLoadTask : public DatabaseTask {
 395  protected:
 396   explicit StoreOrLoadTask(AppCacheStorageImpl* storage)
 397       : DatabaseTask(storage) {}
 398   virtual ~StoreOrLoadTask() {}
 399
 400   bool FindRelatedCacheRecords(int64 cache_id);
 401   void CreateCacheAndGroupFromRecords(
 402       scoped_refptr<AppCache>* cache, scoped_refptr<AppCacheGroup>* group);
 403
 404   AppCacheDatabase::GroupRecord group_record_;
 405   AppCacheDatabase::CacheRecord cache_record_;
 406   std::vector<AppCacheDatabase::EntryRecord> entry_records_;
 407   std::vector<AppCacheDatabase::NamespaceRecord>
 408       intercept_namespace_records_;
 409   std::vector<AppCacheDatabase::NamespaceRecord>
 410       fallback_namespace_records_;
 411   std::vector<AppCacheDatabase::OnlineWhiteListRecord>
 412       online_whitelist_records_;
 413 };
 414
 415 bool AppCacheStorageImpl::StoreOrLoadTask::FindRelatedCacheRecords(
 416     int64 cache_id) {
 417   return database_->FindEntriesForCache(cache_id, &entry_records_) &&
 418          database_->FindNamespacesForCache(
 419              cache_id, &intercept_namespace_records_,
 420              &fallback_namespace_records_) &&
 421          database_->FindOnlineWhiteListForCache(
 422              cache_id, &online_whitelist_records_);
 423 }
 424
 425 void AppCacheStorageImpl::StoreOrLoadTask::CreateCacheAndGroupFromRecords(
 426     scoped_refptr<AppCache>* cache, scoped_refptr<AppCacheGroup>* group) {
 427   DCHECK(storage_ && cache && group);
 428
 429   (*cache) = storage_->working_set_.GetCache(cache_record_.cache_id);
 430   if (cache->get()) {
 431     (*group) = cache->get()->owning_group();
 432     DCHECK(group->get());
 433     DCHECK_EQ(group_record_.group_id, group->get()->group_id());
 434
 435     // TODO(michaeln): histogram is fishing for clues to crbug/95101
 436     if (!cache->get()->GetEntry(group_record_.manifest_url)) {
 437       AppCacheHistograms::AddMissingManifestDetectedAtCallsite(
 438           AppCacheHistograms::CALLSITE_0);
 439     }
 440
 441     storage_->NotifyStorageAccessed(group_record_.origin);
 442     return;
 443   }
 444
 445   (*cache) = new AppCache(storage_, cache_record_.cache_id);
 446   cache->get()->InitializeWithDatabaseRecords(
 447       cache_record_, entry_records_,
 448       intercept_namespace_records_,
 449       fallback_namespace_records_,
 450       online_whitelist_records_);
 451   cache->get()->set_complete(true);
 452
 453   (*group) = storage_->working_set_.GetGroup(group_record_.manifest_url);
 454   if (group->get()) {
 455     DCHECK(group_record_.group_id == group->get()->group_id());
 456     group->get()->AddCache(cache->get());
 457
 458     // TODO(michaeln): histogram is fishing for clues to crbug/95101
 459     if (!cache->get()->GetEntry(group_record_.manifest_url)) {
 460       AppCacheHistograms::AddMissingManifestDetectedAtCallsite(
 461           AppCacheHistograms::CALLSITE_1);
 462     }
 463   } else {
 464     (*group) = new AppCacheGroup(
 465         storage_, group_record_.manifest_url,
 466         group_record_.group_id);
 467     group->get()->set_creation_time(group_record_.creation_time);
 468     group->get()->AddCache(cache->get());
 469
 470     // TODO(michaeln): histogram is fishing for clues to crbug/95101
 471     if (!cache->get()->GetEntry(group_record_.manifest_url)) {
 472       AppCacheHistograms::AddMissingManifestDetectedAtCallsite(
 473           AppCacheHistograms::CALLSITE_2);
 474     }
 475   }
 476   DCHECK(group->get()->newest_complete_cache() == cache->get());
 477
 478   // We have to update foriegn entries if MarkEntryAsForeignTasks
 479   // are in flight.
 480   std::vector<GURL> urls;
 481   storage_->GetPendingForeignMarkingsForCache(cache->get()->cache_id(), &urls);
 482   for (std::vector<GURL>::iterator iter = urls.begin();
 483        iter != urls.end(); ++iter) {
 484     DCHECK(cache->get()->GetEntry(*iter));
 485     cache->get()->GetEntry(*iter)->add_types(AppCacheEntry::FOREIGN);
 486   }
 487
 488   storage_->NotifyStorageAccessed(group_record_.origin);
 489
 490   // TODO(michaeln): Maybe verify that the responses we expect to exist
 491   // do actually exist in the disk_cache (and if not then what?)
 492 }
 493
 494 // CacheLoadTask -------
 495
 496 class AppCacheStorageImpl::CacheLoadTask : public StoreOrLoadTask {
 497  public:
 498   CacheLoadTask(int64 cache_id, AppCacheStorageImpl* storage)
 499       : StoreOrLoadTask(storage), cache_id_(cache_id),
 500         success_(false) {}
 501
 502   // DatabaseTask:
 503   virtual void Run() OVERRIDE;
 504   virtual void RunCompleted() OVERRIDE;
 505
 506  protected:
 507   virtual ~CacheLoadTask() {}
 508
 509  private:
 510   int64 cache_id_;
 511   bool success_;
 512 };
 513
 514 void AppCacheStorageImpl::CacheLoadTask::Run() {
 515   success_ =
 516       database_->FindCache(cache_id_, &cache_record_) &&
 517       database_->FindGroup(cache_record_.group_id, &group_record_) &&
 518       FindRelatedCacheRecords(cache_id_);
 519
 520   if (success_)
 521     database_->UpdateGroupLastAccessTime(group_record_.group_id,
 522                                          base::Time::Now());
 523 }
 524
 525 void AppCacheStorageImpl::CacheLoadTask::RunCompleted() {
 526   storage_->pending_cache_loads_.erase(cache_id_);
 527   scoped_refptr<AppCache> cache;
 528   scoped_refptr<AppCacheGroup> group;
 529   if (success_ && !storage_->is_disabled()) {
 530     DCHECK(cache_record_.cache_id == cache_id_);
 531     CreateCacheAndGroupFromRecords(&cache, &group);
 532   }
 533   FOR_EACH_DELEGATE(delegates_, OnCacheLoaded(cache.get(), cache_id_));
 534 }
 535
 536 // GroupLoadTask -------
 537
 538 class AppCacheStorageImpl::GroupLoadTask : public StoreOrLoadTask {
 539  public:
 540   GroupLoadTask(GURL manifest_url, AppCacheStorageImpl* storage)
 541       : StoreOrLoadTask(storage), manifest_url_(manifest_url),
 542         success_(false) {}
 543
 544   // DatabaseTask:
 545   virtual void Run() OVERRIDE;
 546   virtual void RunCompleted() OVERRIDE;
 547
 548  protected:
 549   virtual ~GroupLoadTask() {}
 550
 551  private:
 552   GURL manifest_url_;
 553   bool success_;
 554 };
 555
 556 void AppCacheStorageImpl::GroupLoadTask::Run() {
 557   success_ =
 558       database_->FindGroupForManifestUrl(manifest_url_, &group_record_) &&
 559       database_->FindCacheForGroup(group_record_.group_id, &cache_record_) &&
 560       FindRelatedCacheRecords(cache_record_.cache_id);
 561
 562   if (success_)
 563     database_->UpdateGroupLastAccessTime(group_record_.group_id,
 564                                          base::Time::Now());
 565 }
 566
 567 void AppCacheStorageImpl::GroupLoadTask::RunCompleted() {
 568   storage_->pending_group_loads_.erase(manifest_url_);
 569   scoped_refptr<AppCacheGroup> group;
 570   scoped_refptr<AppCache> cache;
 571   if (!storage_->is_disabled()) {
 572     if (success_) {
 573       DCHECK(group_record_.manifest_url == manifest_url_);
 574       CreateCacheAndGroupFromRecords(&cache, &group);
 575     } else {
 576       group = storage_->working_set_.GetGroup(manifest_url_);
 577       if (!group.get()) {
 578         group =
 579             new AppCacheGroup(storage_, manifest_url_, storage_->NewGroupId());
 580       }
 581     }
 582   }
 583   FOR_EACH_DELEGATE(delegates_, OnGroupLoaded(group.get(), manifest_url_));
 584 }
 585
 586 // StoreGroupAndCacheTask -------
 587
 588 class AppCacheStorageImpl::StoreGroupAndCacheTask : public StoreOrLoadTask {
 589  public:
 590   StoreGroupAndCacheTask(AppCacheStorageImpl* storage, AppCacheGroup* group,
 591                          AppCache* newest_cache);
 592
 593   void GetQuotaThenSchedule();
 594   void OnQuotaCallback(storage::QuotaStatusCode status,
 595                        int64 usage,
 596                        int64 quota);
 597
 598   // DatabaseTask:
 599   virtual void Run() OVERRIDE;
 600   virtual void RunCompleted() OVERRIDE;
 601   virtual void CancelCompletion() OVERRIDE;
 602
 603  protected:
 604   virtual ~StoreGroupAndCacheTask() {}
 605
 606  private:
 607   scoped_refptr<AppCacheGroup> group_;
 608   scoped_refptr<AppCache> cache_;
 609   bool success_;
 610   bool would_exceed_quota_;
 611   int64 space_available_;
 612   int64 new_origin_usage_;
 613   std::vector<int64> newly_deletable_response_ids_;
 614 };
 615
 616 AppCacheStorageImpl::StoreGroupAndCacheTask::StoreGroupAndCacheTask(
 617     AppCacheStorageImpl* storage, AppCacheGroup* group, AppCache* newest_cache)
 618     : StoreOrLoadTask(storage), group_(group), cache_(newest_cache),
 619       success_(false), would_exceed_quota_(false),
 620       space_available_(-1), new_origin_usage_(-1) {
 621   group_record_.group_id = group->group_id();
 622   group_record_.manifest_url = group->manifest_url();
 623   group_record_.origin = group_record_.manifest_url.GetOrigin();
 624   newest_cache->ToDatabaseRecords(
 625       group,
 626       &cache_record_, &entry_records_,
 627       &intercept_namespace_records_,
 628       &fallback_namespace_records_,
 629       &online_whitelist_records_);
 630 }
 631
 632 void AppCacheStorageImpl::StoreGroupAndCacheTask::GetQuotaThenSchedule() {
 633   storage::QuotaManager* quota_manager = NULL;
 634   if (storage_->service()->quota_manager_proxy()) {
 635     quota_manager =
 636         storage_->service()->quota_manager_proxy()->quota_manager();
 637   }
 638
 639   if (!quota_manager) {
 640     if (storage_->service()->special_storage_policy() &&
 641         storage_->service()->special_storage_policy()->IsStorageUnlimited(
 642             group_record_.origin))
 643       space_available_ = kint64max;
 644     Schedule();
 645     return;
 646   }
 647
 648   // We have to ask the quota manager for the value.
 649   storage_->pending_quota_queries_.insert(this);
 650   quota_manager->GetUsageAndQuota(
 651       group_record_.origin,
 652       storage::kStorageTypeTemporary,
 653       base::Bind(&StoreGroupAndCacheTask::OnQuotaCallback, this));
 654 }
 655
 656 void AppCacheStorageImpl::StoreGroupAndCacheTask::OnQuotaCallback(
 657     storage::QuotaStatusCode status,
 658     int64 usage,
 659     int64 quota) {
 660   if (storage_) {
 661     if (status == storage::kQuotaStatusOk)
 662       space_available_ = std::max(static_cast<int64>(0), quota - usage);
 663     else
 664       space_available_ = 0;
 665     storage_->pending_quota_queries_.erase(this);
 666     Schedule();
 667   }
 668 }
 669
 670 void AppCacheStorageImpl::StoreGroupAndCacheTask::Run() {
 671   DCHECK(!success_);
 672   sql::Connection* connection = database_->db_connection();
 673   if (!connection)
 674     return;
 675
 676   sql::Transaction transaction(connection);
 677   if (!transaction.Begin())
 678     return;
 679
 680   int64 old_origin_usage = database_->GetOriginUsage(group_record_.origin);
 681
 682   AppCacheDatabase::GroupRecord existing_group;
 683   success_ = database_->FindGroup(group_record_.group_id, &existing_group);
 684   if (!success_) {
 685     group_record_.creation_time = base::Time::Now();
 686     group_record_.last_access_time = base::Time::Now();
 687     success_ = database_->InsertGroup(&group_record_);
 688   } else {
 689     DCHECK(group_record_.group_id == existing_group.group_id);
 690     DCHECK(group_record_.manifest_url == existing_group.manifest_url);
 691     DCHECK(group_record_.origin == existing_group.origin);
 692
 693     database_->UpdateGroupLastAccessTime(group_record_.group_id,
 694                                          base::Time::Now());
 695
 696     AppCacheDatabase::CacheRecord cache;
 697     if (database_->FindCacheForGroup(group_record_.group_id, &cache)) {
 698       // Get the set of response ids in the old cache.
 699       std::set<int64> existing_response_ids;
 700       database_->FindResponseIdsForCacheAsSet(cache.cache_id,
 701                                               &existing_response_ids);
 702
 703       // Remove those that remain in the new cache.
 704       std::vector<AppCacheDatabase::EntryRecord>::const_iterator entry_iter =
 705           entry_records_.begin();
 706       while (entry_iter != entry_records_.end()) {
 707         existing_response_ids.erase(entry_iter->response_id);
 708         ++entry_iter;
 709       }
 710
 711       // The rest are deletable.
 712       std::set<int64>::const_iterator id_iter = existing_response_ids.begin();
 713       while (id_iter != existing_response_ids.end()) {
 714         newly_deletable_response_ids_.push_back(*id_iter);
 715         ++id_iter;
 716       }
 717
 718       success_ =
 719           database_->DeleteCache(cache.cache_id) &&
 720           database_->DeleteEntriesForCache(cache.cache_id) &&
 721           database_->DeleteNamespacesForCache(cache.cache_id) &&
 722           database_->DeleteOnlineWhiteListForCache(cache.cache_id) &&
 723           database_->InsertDeletableResponseIds(newly_deletable_response_ids_);
 724           // TODO(michaeln): store group_id too with deletable ids
 725     } else {
 726       NOTREACHED() << "A existing group without a cache is unexpected";
 727     }
 728   }
 729
 730   success_ =
 731       success_ &&
 732       database_->InsertCache(&cache_record_) &&
 733       database_->InsertEntryRecords(entry_records_) &&
 734       database_->InsertNamespaceRecords(intercept_namespace_records_) &&
 735       database_->InsertNamespaceRecords(fallback_namespace_records_) &&
 736       database_->InsertOnlineWhiteListRecords(online_whitelist_records_);
 737
 738   if (!success_)
 739     return;
 740
 741   new_origin_usage_ = database_->GetOriginUsage(group_record_.origin);
 742
 743   // Only check quota when the new usage exceeds the old usage.
 744   if (new_origin_usage_ <= old_origin_usage) {
 745     success_ = transaction.Commit();
 746     return;
 747   }
 748
 749   // Use a simple hard-coded value when not using quota management.
 750   if (space_available_ == -1) {
 751     if (new_origin_usage_ > kDefaultQuota) {
 752       would_exceed_quota_ = true;
 753       success_ = false;
 754       return;
 755     }
 756     success_ = transaction.Commit();
 757     return;
 758   }
 759
 760   // Check limits based on the space availbable given to us via the
 761   // quota system.
 762   int64 delta = new_origin_usage_ - old_origin_usage;
 763   if (delta > space_available_) {
 764     would_exceed_quota_ = true;
 765     success_ = false;
 766     return;
 767   }
 768
 769   success_ = transaction.Commit();
 770 }
 771
 772 void AppCacheStorageImpl::StoreGroupAndCacheTask::RunCompleted() {
 773   if (success_) {
 774     storage_->UpdateUsageMapAndNotify(
 775         group_->manifest_url().GetOrigin(), new_origin_usage_);
 776     if (cache_.get() != group_->newest_complete_cache()) {
 777       cache_->set_complete(true);
 778       group_->AddCache(cache_.get());
 779     }
 780     if (group_->creation_time().is_null())
 781       group_->set_creation_time(group_record_.creation_time);
 782     group_->AddNewlyDeletableResponseIds(&newly_deletable_response_ids_);
 783   }
 784   FOR_EACH_DELEGATE(
 785       delegates_,
 786       OnGroupAndNewestCacheStored(
 787           group_.get(), cache_.get(), success_, would_exceed_quota_));
 788   group_ = NULL;
 789   cache_ = NULL;
 790
 791   // TODO(michaeln): if (would_exceed_quota_) what if the current usage
 792   // also exceeds the quota? http://crbug.com/83968
 793 }
 794
 795 void AppCacheStorageImpl::StoreGroupAndCacheTask::CancelCompletion() {
 796   // Overriden to safely drop our reference to the group and cache
 797   // which are not thread safe refcounted.
 798   DatabaseTask::CancelCompletion();
 799   group_ = NULL;
 800   cache_ = NULL;
 801 }
 802
 803 // FindMainResponseTask -------
 804
 805 // Helpers for FindMainResponseTask::Run()
 806 namespace {
 807 class SortByCachePreference
 808     : public std::binary_function<
 809         AppCacheDatabase::EntryRecord,
 810         AppCacheDatabase::EntryRecord,
 811         bool> {
 812  public:
 813   SortByCachePreference(int64 preferred_id, const std::set<int64>& in_use_ids)
 814       : preferred_id_(preferred_id), in_use_ids_(in_use_ids) {
 815   }
 816   bool operator()(
 817       const AppCacheDatabase::EntryRecord& lhs,
 818       const AppCacheDatabase::EntryRecord& rhs) {
 819     return compute_value(lhs) > compute_value(rhs);
 820   }
 821  private:
 822   int compute_value(const AppCacheDatabase::EntryRecord& entry) {
 823     if (entry.cache_id == preferred_id_)
 824       return 100;
 825     else if (in_use_ids_.find(entry.cache_id) != in_use_ids_.end())
 826       return 50;
 827     return 0;
 828   }
 829   int64 preferred_id_;
 830   const std::set<int64>& in_use_ids_;
 831 };
 832
 833 bool SortByLength(
 834     const AppCacheDatabase::NamespaceRecord& lhs,
 835     const AppCacheDatabase::NamespaceRecord& rhs) {
 836   return lhs.namespace_.namespace_url.spec().length() >
 837          rhs.namespace_.namespace_url.spec().length();
 838 }
 839
 840 class NetworkNamespaceHelper {
 841  public:
 842   explicit NetworkNamespaceHelper(AppCacheDatabase* database)
 843       : database_(database) {
 844   }
 845
 846   bool IsInNetworkNamespace(const GURL& url, int64 cache_id) {
 847     typedef std::pair<WhiteListMap::iterator, bool> InsertResult;
 848     InsertResult result = namespaces_map_.insert(
 849         WhiteListMap::value_type(cache_id, AppCacheNamespaceVector()));
 850     if (result.second)
 851       GetOnlineWhiteListForCache(cache_id, &result.first->second);
 852     return AppCache::FindNamespace(result.first->second, url) != NULL;
 853   }
 854
 855  private:
 856   void GetOnlineWhiteListForCache(
 857       int64 cache_id, AppCacheNamespaceVector* namespaces) {
 858     DCHECK(namespaces && namespaces->empty());
 859     typedef std::vector<AppCacheDatabase::OnlineWhiteListRecord>
 860         WhiteListVector;
 861     WhiteListVector records;
 862     if (!database_->FindOnlineWhiteListForCache(cache_id, &records))
 863       return;
 864     WhiteListVector::const_iterator iter = records.begin();
 865     while (iter != records.end()) {
 866       namespaces->push_back(
 867             AppCacheNamespace(APPCACHE_NETWORK_NAMESPACE, iter->namespace_url,
 868                 GURL(), iter->is_pattern));
 869       ++iter;
 870     }
 871   }
 872
 873   // Key is cache id
 874   typedef std::map<int64, AppCacheNamespaceVector> WhiteListMap;
 875   WhiteListMap namespaces_map_;
 876   AppCacheDatabase* database_;
 877 };
 878
 879 }  // namespace
 880
 881 class AppCacheStorageImpl::FindMainResponseTask : public DatabaseTask {
 882  public:
 883   FindMainResponseTask(AppCacheStorageImpl* storage,
 884                        const GURL& url,
 885                        const GURL& preferred_manifest_url,
 886                        const AppCacheWorkingSet::GroupMap* groups_in_use)
 887       : DatabaseTask(storage), url_(url),
 888         preferred_manifest_url_(preferred_manifest_url),
 889         cache_id_(kAppCacheNoCacheId), group_id_(0) {
 890     if (groups_in_use) {
 891       for (AppCacheWorkingSet::GroupMap::const_iterator it =
 892                groups_in_use->begin();
 893            it != groups_in_use->end(); ++it) {
 894         AppCacheGroup* group = it->second;
 895         AppCache* cache = group->newest_complete_cache();
 896         if (group->is_obsolete() || !cache)
 897           continue;
 898         cache_ids_in_use_.insert(cache->cache_id());
 899       }
 900     }
 901   }
 902
 903   // DatabaseTask:
 904   virtual void Run() OVERRIDE;
 905   virtual void RunCompleted() OVERRIDE;
 906
 907  protected:
 908   virtual ~FindMainResponseTask() {}
 909
 910  private:
 911   typedef std::vector<AppCacheDatabase::NamespaceRecord*>
 912       NamespaceRecordPtrVector;
 913
 914   bool FindExactMatch(int64 preferred_id);
 915   bool FindNamespaceMatch(int64 preferred_id);
 916   bool FindNamespaceHelper(
 917       int64 preferred_cache_id,
 918       AppCacheDatabase::NamespaceRecordVector* namespaces,
 919       NetworkNamespaceHelper* network_namespace_helper);
 920   bool FindFirstValidNamespace(const NamespaceRecordPtrVector& namespaces);
 921
 922   GURL url_;
 923   GURL preferred_manifest_url_;
 924   std::set<int64> cache_ids_in_use_;
 925   AppCacheEntry entry_;
 926   AppCacheEntry fallback_entry_;
 927   GURL namespace_entry_url_;
 928   int64 cache_id_;
 929   int64 group_id_;
 930   GURL manifest_url_;
 931 };
 932
 933 void AppCacheStorageImpl::FindMainResponseTask::Run() {
 934   // NOTE: The heuristics around choosing amoungst multiple candidates
 935   // is underspecified, and just plain not fully understood. This needs
 936   // to be refined.
 937
 938   // The 'preferred_manifest_url' is the url of the manifest associated
 939   // with the page that opened or embedded the page being loaded now.
 940   // We have a strong preference to use resources from that cache.
 941   // We also have a lesser bias to use resources from caches that are currently
 942   // being used by other unrelated pages.
 943   // TODO(michaeln): come up with a 'preferred_manifest_url' in more cases
 944   // - when navigating a frame whose current contents are from an appcache
 945   // - when clicking an href in a frame that is appcached
 946   int64 preferred_cache_id = kAppCacheNoCacheId;
 947   if (!preferred_manifest_url_.is_empty()) {
 948     AppCacheDatabase::GroupRecord preferred_group;
 949     AppCacheDatabase::CacheRecord preferred_cache;
 950     if (database_->FindGroupForManifestUrl(
 951             preferred_manifest_url_, &preferred_group) &&
 952         database_->FindCacheForGroup(
 953             preferred_group.group_id, &preferred_cache)) {
 954       preferred_cache_id = preferred_cache.cache_id;
 955     }
 956   }
 957
 958   if (FindExactMatch(preferred_cache_id) ||
 959       FindNamespaceMatch(preferred_cache_id)) {
 960     // We found something.
 961     DCHECK(cache_id_ != kAppCacheNoCacheId && !manifest_url_.is_empty() &&
 962            group_id_ != 0);
 963     return;
 964   }
 965
 966   // We didn't find anything.
 967   DCHECK(cache_id_ == kAppCacheNoCacheId && manifest_url_.is_empty() &&
 968          group_id_ == 0);
 969 }
 970
 971 bool AppCacheStorageImpl::
 972 FindMainResponseTask::FindExactMatch(int64 preferred_cache_id) {
 973   std::vector<AppCacheDatabase::EntryRecord> entries;
 974   if (database_->FindEntriesForUrl(url_, &entries) && !entries.empty()) {
 975     // Sort them in order of preference, from the preferred_cache first,
 976     // followed by hits from caches that are 'in use', then the rest.
 977     std::sort(entries.begin(), entries.end(),
 978               SortByCachePreference(preferred_cache_id, cache_ids_in_use_));
 979
 980     // Take the first with a valid, non-foreign entry.
 981     std::vector<AppCacheDatabase::EntryRecord>::iterator iter;
 982     for (iter = entries.begin(); iter < entries.end(); ++iter) {
 983       AppCacheDatabase::GroupRecord group_record;
 984       if ((iter->flags & AppCacheEntry::FOREIGN) ||
 985           !database_->FindGroupForCache(iter->cache_id, &group_record)) {
 986         continue;
 987       }
 988       manifest_url_ = group_record.manifest_url;
 989       group_id_ = group_record.group_id;
 990       entry_ = AppCacheEntry(iter->flags, iter->response_id);
 991       cache_id_ = iter->cache_id;
 992       return true;  // We found an exact match.
 993     }
 994   }
 995   return false;
 996 }
 997
 998 bool AppCacheStorageImpl::
 999 FindMainResponseTask::FindNamespaceMatch(int64 preferred_cache_id) {
1000   AppCacheDatabase::NamespaceRecordVector all_intercepts;
1001   AppCacheDatabase::NamespaceRecordVector all_fallbacks;
1002   if (!database_->FindNamespacesForOrigin(
1003           url_.GetOrigin(), &all_intercepts, &all_fallbacks)
1004       || (all_intercepts.empty() && all_fallbacks.empty())) {
1005     return false;
1006   }
1007
1008   NetworkNamespaceHelper network_namespace_helper(database_);
1009   if (FindNamespaceHelper(preferred_cache_id,
1010                           &all_intercepts,
1011                           &network_namespace_helper) ||
1012       FindNamespaceHelper(preferred_cache_id,
1013                           &all_fallbacks,
1014                           &network_namespace_helper)) {
1015     return true;
1016   }
1017   return false;
1018 }
1019
1020 bool AppCacheStorageImpl::
1021 FindMainResponseTask::FindNamespaceHelper(
1022     int64 preferred_cache_id,
1023     AppCacheDatabase::NamespaceRecordVector* namespaces,
1024     NetworkNamespaceHelper* network_namespace_helper) {
1025   // Sort them by length, longer matches within the same cache/bucket take
1026   // precedence.
1027   std::sort(namespaces->begin(), namespaces->end(), SortByLength);
1028
1029   NamespaceRecordPtrVector preferred_namespaces;
1030   NamespaceRecordPtrVector inuse_namespaces;
1031   NamespaceRecordPtrVector other_namespaces;
1032   std::vector<AppCacheDatabase::NamespaceRecord>::iterator iter;
1033   for (iter = namespaces->begin(); iter < namespaces->end(); ++iter) {
1034     // Skip those that aren't a match.
1035     if (!iter->namespace_.IsMatch(url_))
1036       continue;
1037
1038     // Skip namespaces where the requested url falls into a network
1039     // namespace of its containing appcache.
1040     if (network_namespace_helper->IsInNetworkNamespace(url_, iter->cache_id))
1041       continue;
1042
1043     // Bin them into one of our three buckets.
1044     if (iter->cache_id == preferred_cache_id)
1045       preferred_namespaces.push_back(&(*iter));
1046     else if (cache_ids_in_use_.find(iter->cache_id) != cache_ids_in_use_.end())
1047       inuse_namespaces.push_back(&(*iter));
1048     else
1049       other_namespaces.push_back(&(*iter));
1050   }
1051
1052   if (FindFirstValidNamespace(preferred_namespaces) ||
1053       FindFirstValidNamespace(inuse_namespaces) ||
1054       FindFirstValidNamespace(other_namespaces))
1055     return true;  // We found one.
1056
1057   // We didn't find anything.
1058   return false;
1059 }
1060
1061 bool AppCacheStorageImpl::
1062 FindMainResponseTask::FindFirstValidNamespace(
1063     const NamespaceRecordPtrVector& namespaces) {
1064   // Take the first with a valid, non-foreign entry.
1065   NamespaceRecordPtrVector::const_iterator iter;
1066   for (iter = namespaces.begin(); iter < namespaces.end();  ++iter) {
1067     AppCacheDatabase::EntryRecord entry_record;
1068     if (database_->FindEntry((*iter)->cache_id, (*iter)->namespace_.target_url,
1069                              &entry_record)) {
1070       AppCacheDatabase::GroupRecord group_record;
1071       if ((entry_record.flags & AppCacheEntry::FOREIGN) ||
1072           !database_->FindGroupForCache(entry_record.cache_id, &group_record)) {
1073         continue;
1074       }
1075       manifest_url_ = group_record.manifest_url;
1076       group_id_ = group_record.group_id;
1077       cache_id_ = (*iter)->cache_id;
1078       namespace_entry_url_ = (*iter)->namespace_.target_url;
1079       if ((*iter)->namespace_.type == APPCACHE_FALLBACK_NAMESPACE)
1080         fallback_entry_ = AppCacheEntry(entry_record.flags,
1081                                         entry_record.response_id);
1082       else
1083         entry_ = AppCacheEntry(entry_record.flags, entry_record.response_id);
1084       return true;  // We found one.
1085     }
1086   }
1087   return false;  // We didn't find a match.
1088 }
1089
1090 void AppCacheStorageImpl::FindMainResponseTask::RunCompleted() {
1091   storage_->CallOnMainResponseFound(
1092       &delegates_, url_, entry_, namespace_entry_url_, fallback_entry_,
1093       cache_id_, group_id_, manifest_url_);
1094 }
1095
1096 // MarkEntryAsForeignTask -------
1097
1098 class AppCacheStorageImpl::MarkEntryAsForeignTask : public DatabaseTask {
1099  public:
1100   MarkEntryAsForeignTask(
1101       AppCacheStorageImpl* storage, const GURL& url, int64 cache_id)
1102       : DatabaseTask(storage), cache_id_(cache_id), entry_url_(url) {}
1103
1104   // DatabaseTask:
1105   virtual void Run() OVERRIDE;
1106   virtual void RunCompleted() OVERRIDE;
1107
1108  protected:
1109   virtual ~MarkEntryAsForeignTask() {}
1110
1111  private:
1112   int64 cache_id_;
1113   GURL entry_url_;
1114 };
1115
1116 void AppCacheStorageImpl::MarkEntryAsForeignTask::Run() {
1117   database_->AddEntryFlags(entry_url_, cache_id_, AppCacheEntry::FOREIGN);
1118 }
1119
1120 void AppCacheStorageImpl::MarkEntryAsForeignTask::RunCompleted() {
1121   DCHECK(storage_->pending_foreign_markings_.front().first == entry_url_ &&
1122          storage_->pending_foreign_markings_.front().second == cache_id_);
1123   storage_->pending_foreign_markings_.pop_front();
1124 }
1125
1126 // MakeGroupObsoleteTask -------
1127
1128 class AppCacheStorageImpl::MakeGroupObsoleteTask : public DatabaseTask {
1129  public:
1130   MakeGroupObsoleteTask(AppCacheStorageImpl* storage,
1131                         AppCacheGroup* group,
1132                         int response_code);
1133
1134   // DatabaseTask:
1135   virtual void Run() OVERRIDE;
1136   virtual void RunCompleted() OVERRIDE;
1137   virtual void CancelCompletion() OVERRIDE;
1138
1139  protected:
1140   virtual ~MakeGroupObsoleteTask() {}
1141
1142  private:
1143   scoped_refptr<AppCacheGroup> group_;
1144   int64 group_id_;
1145   GURL origin_;
1146   bool success_;
1147   int response_code_;
1148   int64 new_origin_usage_;
1149   std::vector<int64> newly_deletable_response_ids_;
1150 };
1151
1152 AppCacheStorageImpl::MakeGroupObsoleteTask::MakeGroupObsoleteTask(
1153     AppCacheStorageImpl* storage,
1154     AppCacheGroup* group,
1155     int response_code)
1156     : DatabaseTask(storage),
1157       group_(group),
1158       group_id_(group->group_id()),
1159       origin_(group->manifest_url().GetOrigin()),
1160       success_(false),
1161       response_code_(response_code),
1162       new_origin_usage_(-1) {}
1163
1164 void AppCacheStorageImpl::MakeGroupObsoleteTask::Run() {
1165   DCHECK(!success_);
1166   sql::Connection* connection = database_->db_connection();
1167   if (!connection)
1168     return;
1169
1170   sql::Transaction transaction(connection);
1171   if (!transaction.Begin())
1172     return;
1173
1174   AppCacheDatabase::GroupRecord group_record;
1175   if (!database_->FindGroup(group_id_, &group_record)) {
1176     // This group doesn't exists in the database, nothing todo here.
1177     new_origin_usage_ = database_->GetOriginUsage(origin_);
1178     success_ = true;
1179     return;
1180   }
1181
1182   DCHECK_EQ(group_record.origin, origin_);
1183   success_ = DeleteGroupAndRelatedRecords(database_,
1184                                           group_id_,
1185                                           &newly_deletable_response_ids_);
1186
1187   new_origin_usage_ = database_->GetOriginUsage(origin_);
1188   success_ = success_ && transaction.Commit();
1189 }
1190
1191 void AppCacheStorageImpl::MakeGroupObsoleteTask::RunCompleted() {
1192   if (success_) {
1193     group_->set_obsolete(true);
1194     if (!storage_->is_disabled()) {
1195       storage_->UpdateUsageMapAndNotify(origin_, new_origin_usage_);
1196       group_->AddNewlyDeletableResponseIds(&newly_deletable_response_ids_);
1197
1198       // Also remove from the working set, caches for an 'obsolete' group
1199       // may linger in use, but the group itself cannot be looked up by
1200       // 'manifest_url' in the working set any longer.
1201       storage_->working_set()->RemoveGroup(group_.get());
1202     }
1203   }
1204   FOR_EACH_DELEGATE(
1205       delegates_, OnGroupMadeObsolete(group_.get(), success_, response_code_));
1206   group_ = NULL;
1207 }
1208
1209 void AppCacheStorageImpl::MakeGroupObsoleteTask::CancelCompletion() {
1210   // Overriden to safely drop our reference to the group
1211   // which is not thread safe refcounted.
1212   DatabaseTask::CancelCompletion();
1213   group_ = NULL;
1214 }
1215
1216 // GetDeletableResponseIdsTask -------
1217
1218 class AppCacheStorageImpl::GetDeletableResponseIdsTask : public DatabaseTask {
1219  public:
1220   GetDeletableResponseIdsTask(AppCacheStorageImpl* storage, int64 max_rowid)
1221       : DatabaseTask(storage), max_rowid_(max_rowid) {}
1222
1223   // DatabaseTask:
1224   virtual void Run() OVERRIDE;
1225   virtual void RunCompleted() OVERRIDE;
1226
1227  protected:
1228   virtual ~GetDeletableResponseIdsTask() {}
1229
1230  private:
1231   int64 max_rowid_;
1232   std::vector<int64> response_ids_;
1233 };
1234
1235 void AppCacheStorageImpl::GetDeletableResponseIdsTask::Run() {
1236   const int kSqlLimit = 1000;
1237   database_->GetDeletableResponseIds(&response_ids_, max_rowid_, kSqlLimit);
1238   // TODO(michaeln): retrieve group_ids too
1239 }
1240
1241 void AppCacheStorageImpl::GetDeletableResponseIdsTask::RunCompleted() {
1242   if (!response_ids_.empty())
1243     storage_->StartDeletingResponses(response_ids_);
1244 }
1245
1246 // InsertDeletableResponseIdsTask -------
1247
1248 class AppCacheStorageImpl::InsertDeletableResponseIdsTask
1249     : public DatabaseTask {
1250  public:
1251   explicit InsertDeletableResponseIdsTask(AppCacheStorageImpl* storage)
1252       : DatabaseTask(storage) {}
1253
1254   // DatabaseTask:
1255   virtual void Run() OVERRIDE;
1256
1257   std::vector<int64> response_ids_;
1258
1259  protected:
1260   virtual ~InsertDeletableResponseIdsTask() {}
1261 };
1262
1263 void AppCacheStorageImpl::InsertDeletableResponseIdsTask::Run() {
1264   database_->InsertDeletableResponseIds(response_ids_);
1265   // TODO(michaeln): store group_ids too
1266 }
1267
1268 // DeleteDeletableResponseIdsTask -------
1269
1270 class AppCacheStorageImpl::DeleteDeletableResponseIdsTask
1271     : public DatabaseTask {
1272  public:
1273   explicit DeleteDeletableResponseIdsTask(AppCacheStorageImpl* storage)
1274       : DatabaseTask(storage) {}
1275
1276   // DatabaseTask:
1277   virtual void Run() OVERRIDE;
1278
1279   std::vector<int64> response_ids_;
1280
1281  protected:
1282   virtual ~DeleteDeletableResponseIdsTask() {}
1283 };
1284
1285 void AppCacheStorageImpl::DeleteDeletableResponseIdsTask::Run() {
1286   database_->DeleteDeletableResponseIds(response_ids_);
1287 }
1288
1289 // UpdateGroupLastAccessTimeTask -------
1290
1291 class AppCacheStorageImpl::UpdateGroupLastAccessTimeTask
1292     : public DatabaseTask {
1293  public:
1294   UpdateGroupLastAccessTimeTask(
1295       AppCacheStorageImpl* storage, AppCacheGroup* group, base::Time time)
1296       : DatabaseTask(storage), group_id_(group->group_id()),
1297         last_access_time_(time) {
1298     storage->NotifyStorageAccessed(group->manifest_url().GetOrigin());
1299   }
1300
1301   // DatabaseTask:
1302   virtual void Run() OVERRIDE;
1303
1304  protected:
1305   virtual ~UpdateGroupLastAccessTimeTask() {}
1306
1307  private:
1308   int64 group_id_;
1309   base::Time last_access_time_;
1310 };
1311
1312 void AppCacheStorageImpl::UpdateGroupLastAccessTimeTask::Run() {
1313   database_->UpdateGroupLastAccessTime(group_id_, last_access_time_);
1314 }
1315
1316
1317 // AppCacheStorageImpl ---------------------------------------------------
1318
1319 AppCacheStorageImpl::AppCacheStorageImpl(AppCacheServiceImpl* service)
1320     : AppCacheStorage(service),
1321       is_incognito_(false),
1322       is_response_deletion_scheduled_(false),
1323       did_start_deleting_responses_(false),
1324       last_deletable_response_rowid_(0),
1325       database_(NULL),
1326       is_disabled_(false),
1327       weak_factory_(this) {
1328 }
1329
1330 AppCacheStorageImpl::~AppCacheStorageImpl() {
1331   std::for_each(pending_quota_queries_.begin(),
1332                 pending_quota_queries_.end(),
1333                 std::mem_fun(&DatabaseTask::CancelCompletion));
1334   std::for_each(scheduled_database_tasks_.begin(),
1335                 scheduled_database_tasks_.end(),
1336                 std::mem_fun(&DatabaseTask::CancelCompletion));
1337
1338   if (database_ &&
1339       !db_thread_->PostTask(
1340           FROM_HERE,
1341           base::Bind(&ClearSessionOnlyOrigins,
1342                      database_,
1343                      make_scoped_refptr(service_->special_storage_policy()),
1344                      service()->force_keep_session_state()))) {
1345     delete database_;
1346   }
1347   database_ = NULL;  // So no further database tasks can be scheduled.
1348 }
1349
1350 void AppCacheStorageImpl::Initialize(
1351     const base::FilePath& cache_directory,
1352     const scoped_refptr<base::SingleThreadTaskRunner>& db_thread,
1353     const scoped_refptr<base::SingleThreadTaskRunner>& cache_thread) {
1354   DCHECK(db_thread.get());
1355
1356   cache_directory_ = cache_directory;
1357   is_incognito_ = cache_directory_.empty();
1358
1359   base::FilePath db_file_path;
1360   if (!is_incognito_)
1361     db_file_path = cache_directory_.Append(kAppCacheDatabaseName);
1362   database_ = new AppCacheDatabase(db_file_path);
1363
1364   db_thread_ = db_thread;
1365   cache_thread_ = cache_thread;
1366
1367   scoped_refptr<InitTask> task(new InitTask(this));
1368   task->Schedule();
1369 }
1370
1371 void AppCacheStorageImpl::Disable() {
1372   if (is_disabled_)
1373     return;
1374   VLOG(1) << "Disabling appcache storage.";
1375   is_disabled_ = true;
1376   ClearUsageMapAndNotify();
1377   working_set()->Disable();
1378   if (disk_cache_)
1379     disk_cache_->Disable();
1380   scoped_refptr<DisableDatabaseTask> task(new DisableDatabaseTask(this));
1381   task->Schedule();
1382 }
1383
1384 void AppCacheStorageImpl::GetAllInfo(Delegate* delegate) {
1385   DCHECK(delegate);
1386   scoped_refptr<GetAllInfoTask> task(new GetAllInfoTask(this));
1387   task->AddDelegate(GetOrCreateDelegateReference(delegate));
1388   task->Schedule();
1389 }
1390
1391 void AppCacheStorageImpl::LoadCache(int64 id, Delegate* delegate) {
1392   DCHECK(delegate);
1393   if (is_disabled_) {
1394     delegate->OnCacheLoaded(NULL, id);
1395     return;
1396   }
1397
1398   AppCache* cache = working_set_.GetCache(id);
1399   if (cache) {
1400     delegate->OnCacheLoaded(cache, id);
1401     if (cache->owning_group()) {
1402       scoped_refptr<DatabaseTask> update_task(
1403           new UpdateGroupLastAccessTimeTask(
1404               this, cache->owning_group(), base::Time::Now()));
1405       update_task->Schedule();
1406     }
1407     return;
1408   }
1409   scoped_refptr<CacheLoadTask> task(GetPendingCacheLoadTask(id));
1410   if (task.get()) {
1411     task->AddDelegate(GetOrCreateDelegateReference(delegate));
1412     return;
1413   }
1414   task = new CacheLoadTask(id, this);
1415   task->AddDelegate(GetOrCreateDelegateReference(delegate));
1416   task->Schedule();
1417   pending_cache_loads_[id] = task.get();
1418 }
1419
1420 void AppCacheStorageImpl::LoadOrCreateGroup(
1421     const GURL& manifest_url, Delegate* delegate) {
1422   DCHECK(delegate);
1423   if (is_disabled_) {
1424     delegate->OnGroupLoaded(NULL, manifest_url);
1425     return;
1426   }
1427
1428   AppCacheGroup* group = working_set_.GetGroup(manifest_url);
1429   if (group) {
1430     delegate->OnGroupLoaded(group, manifest_url);
1431     scoped_refptr<DatabaseTask> update_task(
1432         new UpdateGroupLastAccessTimeTask(
1433             this, group, base::Time::Now()));
1434     update_task->Schedule();
1435     return;
1436   }
1437
1438   scoped_refptr<GroupLoadTask> task(GetPendingGroupLoadTask(manifest_url));
1439   if (task.get()) {
1440     task->AddDelegate(GetOrCreateDelegateReference(delegate));
1441     return;
1442   }
1443
1444   if (usage_map_.find(manifest_url.GetOrigin()) == usage_map_.end()) {
1445     // No need to query the database, return a new group immediately.
1446     scoped_refptr<AppCacheGroup> group(new AppCacheGroup(
1447         this, manifest_url, NewGroupId()));
1448     delegate->OnGroupLoaded(group.get(), manifest_url);
1449     return;
1450   }
1451
1452   task = new GroupLoadTask(manifest_url, this);
1453   task->AddDelegate(GetOrCreateDelegateReference(delegate));
1454   task->Schedule();
1455   pending_group_loads_[manifest_url] = task.get();
1456 }
1457
1458 void AppCacheStorageImpl::StoreGroupAndNewestCache(
1459     AppCacheGroup* group, AppCache* newest_cache, Delegate* delegate) {
1460   // TODO(michaeln): distinguish between a simple update of an existing
1461   // cache that just adds new master entry(s), and the insertion of a
1462   // whole new cache. The StoreGroupAndCacheTask as written will handle
1463   // the simple update case in a very heavy weight way (delete all and
1464   // the reinsert all over again).
1465   DCHECK(group && delegate && newest_cache);
1466   scoped_refptr<StoreGroupAndCacheTask> task(
1467       new StoreGroupAndCacheTask(this, group, newest_cache));
1468   task->AddDelegate(GetOrCreateDelegateReference(delegate));
1469   task->GetQuotaThenSchedule();
1470
1471   // TODO(michaeln): histogram is fishing for clues to crbug/95101
1472   if (!newest_cache->GetEntry(group->manifest_url())) {
1473     AppCacheHistograms::AddMissingManifestDetectedAtCallsite(
1474         AppCacheHistograms::CALLSITE_3);
1475   }
1476 }
1477
1478 void AppCacheStorageImpl::FindResponseForMainRequest(
1479     const GURL& url, const GURL& preferred_manifest_url,
1480     Delegate* delegate) {
1481   DCHECK(delegate);
1482
1483   const GURL* url_ptr = &url;
1484   GURL url_no_ref;
1485   if (url.has_ref()) {
1486     GURL::Replacements replacements;
1487     replacements.ClearRef();
1488     url_no_ref = url.ReplaceComponents(replacements);
1489     url_ptr = &url_no_ref;
1490   }
1491
1492   const GURL origin = url.GetOrigin();
1493
1494   // First look in our working set for a direct hit without having to query
1495   // the database.
1496   const AppCacheWorkingSet::GroupMap* groups_in_use =
1497       working_set()->GetGroupsInOrigin(origin);
1498   if (groups_in_use) {
1499     if (!preferred_manifest_url.is_empty()) {
1500       AppCacheWorkingSet::GroupMap::const_iterator found =
1501           groups_in_use->find(preferred_manifest_url);
1502       if (found != groups_in_use->end() &&
1503           FindResponseForMainRequestInGroup(
1504               found->second, *url_ptr, delegate)) {
1505           return;
1506       }
1507     } else {
1508       for (AppCacheWorkingSet::GroupMap::const_iterator it =
1509               groups_in_use->begin();
1510            it != groups_in_use->end(); ++it) {
1511         if (FindResponseForMainRequestInGroup(
1512                 it->second, *url_ptr, delegate)) {
1513           return;
1514         }
1515       }
1516     }
1517   }
1518
1519   if (IsInitTaskComplete() &&  usage_map_.find(origin) == usage_map_.end()) {
1520     // No need to query the database, return async'ly but without going thru
1521     // the DB thread.
1522     scoped_refptr<AppCacheGroup> no_group;
1523     scoped_refptr<AppCache> no_cache;
1524     ScheduleSimpleTask(
1525         base::Bind(&AppCacheStorageImpl::DeliverShortCircuitedFindMainResponse,
1526                    weak_factory_.GetWeakPtr(), url, AppCacheEntry(), no_group,
1527                    no_cache,
1528                    make_scoped_refptr(GetOrCreateDelegateReference(delegate))));
1529     return;
1530   }
1531
1532   // We have to query the database, schedule a database task to do so.
1533   scoped_refptr<FindMainResponseTask> task(
1534       new FindMainResponseTask(this, *url_ptr, preferred_manifest_url,
1535                                groups_in_use));
1536   task->AddDelegate(GetOrCreateDelegateReference(delegate));
1537   task->Schedule();
1538 }
1539
1540 bool AppCacheStorageImpl::FindResponseForMainRequestInGroup(
1541     AppCacheGroup* group,  const GURL& url, Delegate* delegate) {
1542   AppCache* cache = group->newest_complete_cache();
1543   if (group->is_obsolete() || !cache)
1544     return false;
1545
1546   AppCacheEntry* entry = cache->GetEntry(url);
1547   if (!entry || entry->IsForeign())
1548     return false;
1549
1550   ScheduleSimpleTask(
1551       base::Bind(&AppCacheStorageImpl::DeliverShortCircuitedFindMainResponse,
1552                  weak_factory_.GetWeakPtr(), url, *entry,
1553                  make_scoped_refptr(group), make_scoped_refptr(cache),
1554                  make_scoped_refptr(GetOrCreateDelegateReference(delegate))));
1555   return true;
1556 }
1557
1558 void AppCacheStorageImpl::DeliverShortCircuitedFindMainResponse(
1559     const GURL& url,
1560     const AppCacheEntry& found_entry,
1561     scoped_refptr<AppCacheGroup> group,
1562     scoped_refptr<AppCache> cache,
1563     scoped_refptr<DelegateReference> delegate_ref) {
1564   if (delegate_ref->delegate) {
1565     DelegateReferenceVector delegates(1, delegate_ref);
1566     CallOnMainResponseFound(
1567         &delegates, url, found_entry,
1568         GURL(), AppCacheEntry(),
1569         cache.get() ? cache->cache_id() : kAppCacheNoCacheId,
1570         group.get() ? group->group_id() : kAppCacheNoCacheId,
1571         group.get() ? group->manifest_url() : GURL());
1572   }
1573 }
1574
1575 void AppCacheStorageImpl::CallOnMainResponseFound(
1576     DelegateReferenceVector* delegates,
1577     const GURL& url, const AppCacheEntry& entry,
1578     const GURL& namespace_entry_url, const AppCacheEntry& fallback_entry,
1579     int64 cache_id, int64 group_id, const GURL& manifest_url) {
1580   FOR_EACH_DELEGATE(
1581       (*delegates),
1582       OnMainResponseFound(url, entry,
1583                           namespace_entry_url, fallback_entry,
1584                           cache_id, group_id, manifest_url));
1585 }
1586
1587 void AppCacheStorageImpl::FindResponseForSubRequest(
1588     AppCache* cache, const GURL& url,
1589     AppCacheEntry* found_entry, AppCacheEntry* found_fallback_entry,
1590     bool* found_network_namespace) {
1591   DCHECK(cache && cache->is_complete());
1592
1593   // When a group is forcibly deleted, all subresource loads for pages
1594   // using caches in the group will result in a synthesized network errors.
1595   // Forcible deletion is not a function that is covered by the HTML5 spec.
1596   if (cache->owning_group()->is_being_deleted()) {
1597     *found_entry = AppCacheEntry();
1598     *found_fallback_entry = AppCacheEntry();
1599     *found_network_namespace = false;
1600     return;
1601   }
1602
1603   GURL fallback_namespace_not_used;
1604   GURL intercept_namespace_not_used;
1605   cache->FindResponseForRequest(
1606       url, found_entry, &intercept_namespace_not_used,
1607       found_fallback_entry, &fallback_namespace_not_used,
1608       found_network_namespace);
1609 }
1610
1611 void AppCacheStorageImpl::MarkEntryAsForeign(
1612     const GURL& entry_url, int64 cache_id) {
1613   AppCache* cache = working_set_.GetCache(cache_id);
1614   if (cache) {
1615     AppCacheEntry* entry = cache->GetEntry(entry_url);
1616     DCHECK(entry);
1617     if (entry)
1618       entry->add_types(AppCacheEntry::FOREIGN);
1619   }
1620   scoped_refptr<MarkEntryAsForeignTask> task(
1621       new MarkEntryAsForeignTask(this, entry_url, cache_id));
1622   task->Schedule();
1623   pending_foreign_markings_.push_back(std::make_pair(entry_url, cache_id));
1624 }
1625
1626 void AppCacheStorageImpl::MakeGroupObsolete(AppCacheGroup* group,
1627                                             Delegate* delegate,
1628                                             int response_code) {
1629   DCHECK(group && delegate);
1630   scoped_refptr<MakeGroupObsoleteTask> task(
1631       new MakeGroupObsoleteTask(this, group, response_code));
1632   task->AddDelegate(GetOrCreateDelegateReference(delegate));
1633   task->Schedule();
1634 }
1635
1636 AppCacheResponseReader* AppCacheStorageImpl::CreateResponseReader(
1637     const GURL& manifest_url, int64 group_id, int64 response_id) {
1638   return new AppCacheResponseReader(response_id, group_id, disk_cache());
1639 }
1640
1641 AppCacheResponseWriter* AppCacheStorageImpl::CreateResponseWriter(
1642     const GURL& manifest_url, int64 group_id) {
1643   return new AppCacheResponseWriter(NewResponseId(), group_id, disk_cache());
1644 }
1645
1646 void AppCacheStorageImpl::DoomResponses(
1647     const GURL& manifest_url, const std::vector<int64>& response_ids) {
1648   if (response_ids.empty())
1649     return;
1650
1651   // Start deleting them from the disk cache lazily.
1652   StartDeletingResponses(response_ids);
1653
1654   // Also schedule a database task to record these ids in the
1655   // deletable responses table.
1656   // TODO(michaeln): There is a race here. If the browser crashes
1657   // prior to committing these rows to the database and prior to us
1658   // having deleted them from the disk cache, we'll never delete them.
1659   scoped_refptr<InsertDeletableResponseIdsTask> task(
1660       new InsertDeletableResponseIdsTask(this));
1661   task->response_ids_ = response_ids;
1662   task->Schedule();
1663 }
1664
1665 void AppCacheStorageImpl::DeleteResponses(
1666     const GURL& manifest_url, const std::vector<int64>& response_ids) {
1667   if (response_ids.empty())
1668     return;
1669   StartDeletingResponses(response_ids);
1670 }
1671
1672 void AppCacheStorageImpl::DelayedStartDeletingUnusedResponses() {
1673   // Only if we haven't already begun.
1674   if (!did_start_deleting_responses_) {
1675     scoped_refptr<GetDeletableResponseIdsTask> task(
1676         new GetDeletableResponseIdsTask(this, last_deletable_response_rowid_));
1677     task->Schedule();
1678   }
1679 }
1680
1681 void AppCacheStorageImpl::StartDeletingResponses(
1682     const std::vector<int64>& response_ids) {
1683   DCHECK(!response_ids.empty());
1684   did_start_deleting_responses_ = true;
1685   deletable_response_ids_.insert(
1686       deletable_response_ids_.end(),
1687       response_ids.begin(), response_ids.end());
1688   if (!is_response_deletion_scheduled_)
1689     ScheduleDeleteOneResponse();
1690 }
1691
1692 void AppCacheStorageImpl::ScheduleDeleteOneResponse() {
1693   DCHECK(!is_response_deletion_scheduled_);
1694   const base::TimeDelta kDelay = base::TimeDelta::FromMilliseconds(10);
1695   base::MessageLoop::current()->PostDelayedTask(
1696       FROM_HERE,
1697       base::Bind(&AppCacheStorageImpl::DeleteOneResponse,
1698                  weak_factory_.GetWeakPtr()),
1699       kDelay);
1700   is_response_deletion_scheduled_ = true;
1701 }
1702
1703 void AppCacheStorageImpl::DeleteOneResponse() {
1704   DCHECK(is_response_deletion_scheduled_);
1705   DCHECK(!deletable_response_ids_.empty());
1706
1707   if (!disk_cache()) {
1708     DCHECK(is_disabled_);
1709     deletable_response_ids_.clear();
1710     deleted_response_ids_.clear();
1711     is_response_deletion_scheduled_ = false;
1712     return;
1713   }
1714
1715   // TODO(michaeln): add group_id to DoomEntry args
1716   int64 id = deletable_response_ids_.front();
1717   int rv = disk_cache_->DoomEntry(
1718       id, base::Bind(&AppCacheStorageImpl::OnDeletedOneResponse,
1719                      base::Unretained(this)));
1720   if (rv != net::ERR_IO_PENDING)
1721     OnDeletedOneResponse(rv);
1722 }
1723
1724 void AppCacheStorageImpl::OnDeletedOneResponse(int rv) {
1725   is_response_deletion_scheduled_ = false;
1726   if (is_disabled_)
1727     return;
1728
1729   int64 id = deletable_response_ids_.front();
1730   deletable_response_ids_.pop_front();
1731   if (rv != net::ERR_ABORTED)
1732     deleted_response_ids_.push_back(id);
1733
1734   const size_t kBatchSize = 50U;
1735   if (deleted_response_ids_.size() >= kBatchSize ||
1736       deletable_response_ids_.empty()) {
1737     scoped_refptr<DeleteDeletableResponseIdsTask> task(
1738         new DeleteDeletableResponseIdsTask(this));
1739     task->response_ids_.swap(deleted_response_ids_);
1740     task->Schedule();
1741   }
1742
1743   if (deletable_response_ids_.empty()) {
1744     scoped_refptr<GetDeletableResponseIdsTask> task(
1745         new GetDeletableResponseIdsTask(this, last_deletable_response_rowid_));
1746     task->Schedule();
1747     return;
1748   }
1749
1750   ScheduleDeleteOneResponse();
1751 }
1752
1753 AppCacheStorageImpl::CacheLoadTask*
1754 AppCacheStorageImpl::GetPendingCacheLoadTask(int64 cache_id) {
1755   PendingCacheLoads::iterator found = pending_cache_loads_.find(cache_id);
1756   if (found != pending_cache_loads_.end())
1757     return found->second;
1758   return NULL;
1759 }
1760
1761 AppCacheStorageImpl::GroupLoadTask*
1762 AppCacheStorageImpl::GetPendingGroupLoadTask(const GURL& manifest_url) {
1763   PendingGroupLoads::iterator found = pending_group_loads_.find(manifest_url);
1764   if (found != pending_group_loads_.end())
1765     return found->second;
1766   return NULL;
1767 }
1768
1769 void AppCacheStorageImpl::GetPendingForeignMarkingsForCache(
1770     int64 cache_id, std::vector<GURL>* urls) {
1771   PendingForeignMarkings::iterator iter = pending_foreign_markings_.begin();
1772   while (iter != pending_foreign_markings_.end()) {
1773     if (iter->second == cache_id)
1774       urls->push_back(iter->first);
1775     ++iter;
1776   }
1777 }
1778
1779 void AppCacheStorageImpl::ScheduleSimpleTask(const base::Closure& task) {
1780   pending_simple_tasks_.push_back(task);
1781   base::MessageLoop::current()->PostTask(
1782       FROM_HERE,
1783       base::Bind(&AppCacheStorageImpl::RunOnePendingSimpleTask,
1784                  weak_factory_.GetWeakPtr()));
1785 }
1786
1787 void AppCacheStorageImpl::RunOnePendingSimpleTask() {
1788   DCHECK(!pending_simple_tasks_.empty());
1789   base::Closure task = pending_simple_tasks_.front();
1790   pending_simple_tasks_.pop_front();
1791   task.Run();
1792 }
1793
1794 AppCacheDiskCache* AppCacheStorageImpl::disk_cache() {
1795   DCHECK(IsInitTaskComplete());
1796
1797   if (is_disabled_)
1798     return NULL;
1799
1800   if (!disk_cache_) {
1801     int rv = net::OK;
1802     disk_cache_.reset(new AppCacheDiskCache);
1803     if (is_incognito_) {
1804       rv = disk_cache_->InitWithMemBackend(
1805           kMaxMemDiskCacheSize,
1806           base::Bind(&AppCacheStorageImpl::OnDiskCacheInitialized,
1807                      base::Unretained(this)));
1808     } else {
1809       rv = disk_cache_->InitWithDiskBackend(
1810           cache_directory_.Append(kDiskCacheDirectoryName),
1811           kMaxDiskCacheSize,
1812           false,
1813           cache_thread_.get(),
1814           base::Bind(&AppCacheStorageImpl::OnDiskCacheInitialized,
1815                      base::Unretained(this)));
1816     }
1817
1818     if (rv != net::ERR_IO_PENDING)
1819       OnDiskCacheInitialized(rv);
1820   }
1821   return disk_cache_.get();
1822 }
1823
1824 void AppCacheStorageImpl::OnDiskCacheInitialized(int rv) {
1825   if (rv != net::OK) {
1826     LOG(ERROR) << "Failed to open the appcache diskcache.";
1827     AppCacheHistograms::CountInitResult(AppCacheHistograms::DISK_CACHE_ERROR);
1828
1829     // We're unable to open the disk cache, this is a fatal error that we can't
1830     // really recover from. We handle it by temporarily disabling the appcache
1831     // deleting the directory on disk and reinitializing the appcache system.
1832     Disable();
1833     if (rv != net::ERR_ABORTED)
1834       DeleteAndStartOver();
1835   }
1836 }
1837
1838 void AppCacheStorageImpl::DeleteAndStartOver() {
1839   DCHECK(is_disabled_);
1840   if (!is_incognito_) {
1841     VLOG(1) << "Deleting existing appcache data and starting over.";
1842     // We can have tasks in flight to close file handles on both the db
1843     // and cache threads, we need to allow those tasks to cycle thru
1844     // prior to deleting the files and calling reinit.
1845     cache_thread_->PostTaskAndReply(
1846         FROM_HERE,
1847         base::Bind(&base::DoNothing),
1848         base::Bind(&AppCacheStorageImpl::DeleteAndStartOverPart2,
1849                    weak_factory_.GetWeakPtr()));
1850   }
1851 }
1852
1853 void AppCacheStorageImpl::DeleteAndStartOverPart2() {
1854   db_thread_->PostTaskAndReply(
1855       FROM_HERE,
1856       base::Bind(base::IgnoreResult(&base::DeleteFile), cache_directory_, true),
1857       base::Bind(&AppCacheStorageImpl::CallScheduleReinitialize,
1858                  weak_factory_.GetWeakPtr()));
1859 }
1860
1861 void AppCacheStorageImpl::CallScheduleReinitialize() {
1862   service_->ScheduleReinitialize();
1863   // note: 'this' may be deleted at this point.
1864 }
1865
1866 }  // namespace content