content/browser/dom_storage/dom_storage_area.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 "content/browser/dom_storage/dom_storage_area.h"
   6
   7 #include "base/bind.h"
   8 #include "base/location.h"
   9 #include "base/logging.h"
  10 #include "base/metrics/histogram.h"
  11 #include "base/strings/utf_string_conversions.h"
  12 #include "base/time/time.h"
  13 #include "content/browser/dom_storage/dom_storage_namespace.h"
  14 #include "content/browser/dom_storage/dom_storage_task_runner.h"
  15 #include "content/browser/dom_storage/local_storage_database_adapter.h"
  16 #include "content/browser/dom_storage/session_storage_database.h"
  17 #include "content/browser/dom_storage/session_storage_database_adapter.h"
  18 #include "content/common/dom_storage/dom_storage_map.h"
  19 #include "content/common/dom_storage/dom_storage_types.h"
  20 #include "webkit/browser/database/database_util.h"
  21 #include "webkit/common/database/database_identifier.h"
  22 #include "webkit/common/fileapi/file_system_util.h"
  23
  24 using webkit_database::DatabaseUtil;
  25
  26 namespace content {
  27
  28 static const int kCommitTimerSeconds = 1;
  29
  30 DOMStorageArea::CommitBatch::CommitBatch()
  31   : clear_all_first(false) {
  32 }
  33 DOMStorageArea::CommitBatch::~CommitBatch() {}
  34
  35
  36 // static
  37 const base::FilePath::CharType DOMStorageArea::kDatabaseFileExtension[] =
  38     FILE_PATH_LITERAL(".localstorage");
  39
  40 // static
  41 base::FilePath DOMStorageArea::DatabaseFileNameFromOrigin(const GURL& origin) {
  42   std::string filename = webkit_database::GetIdentifierFromOrigin(origin);
  43   // There is no base::FilePath.AppendExtension() method, so start with just the
  44   // extension as the filename, and then InsertBeforeExtension the desired
  45   // name.
  46   return base::FilePath().Append(kDatabaseFileExtension).
  47       InsertBeforeExtensionASCII(filename);
  48 }
  49
  50 // static
  51 GURL DOMStorageArea::OriginFromDatabaseFileName(const base::FilePath& name) {
  52   DCHECK(name.MatchesExtension(kDatabaseFileExtension));
  53   std::string origin_id =
  54       name.BaseName().RemoveExtension().MaybeAsASCII();
  55   return webkit_database::GetOriginFromIdentifier(origin_id);
  56 }
  57
  58 DOMStorageArea::DOMStorageArea(
  59     const GURL& origin, const base::FilePath& directory,
  60     DOMStorageTaskRunner* task_runner)
  61     : namespace_id_(kLocalStorageNamespaceId), origin_(origin),
  62       directory_(directory),
  63       task_runner_(task_runner),
  64       map_(new DOMStorageMap(kPerStorageAreaQuota +
  65                              kPerStorageAreaOverQuotaAllowance)),
  66       is_initial_import_done_(true),
  67       is_shutdown_(false),
  68       commit_batches_in_flight_(0) {
  69   if (!directory.empty()) {
  70     base::FilePath path = directory.Append(DatabaseFileNameFromOrigin(origin_));
  71     backing_.reset(new LocalStorageDatabaseAdapter(path));
  72     is_initial_import_done_ = false;
  73   }
  74 }
  75
  76 DOMStorageArea::DOMStorageArea(
  77     int64 namespace_id,
  78     const std::string& persistent_namespace_id,
  79     const GURL& origin,
  80     SessionStorageDatabase* session_storage_backing,
  81     DOMStorageTaskRunner* task_runner)
  82     : namespace_id_(namespace_id),
  83       persistent_namespace_id_(persistent_namespace_id),
  84       origin_(origin),
  85       task_runner_(task_runner),
  86       map_(new DOMStorageMap(kPerStorageAreaQuota +
  87                              kPerStorageAreaOverQuotaAllowance)),
  88       session_storage_backing_(session_storage_backing),
  89       is_initial_import_done_(true),
  90       is_shutdown_(false),
  91       commit_batches_in_flight_(0) {
  92   DCHECK(namespace_id != kLocalStorageNamespaceId);
  93   if (session_storage_backing) {
  94     backing_.reset(new SessionStorageDatabaseAdapter(
  95         session_storage_backing, persistent_namespace_id, origin));
  96     is_initial_import_done_ = false;
  97   }
  98 }
  99
 100 DOMStorageArea::~DOMStorageArea() {
 101 }
 102
 103 void DOMStorageArea::ExtractValues(DOMStorageValuesMap* map) {
 104   if (is_shutdown_)
 105     return;
 106   InitialImportIfNeeded();
 107   map_->ExtractValues(map);
 108 }
 109
 110 unsigned DOMStorageArea::Length() {
 111   if (is_shutdown_)
 112     return 0;
 113   InitialImportIfNeeded();
 114   return map_->Length();
 115 }
 116
 117 base::NullableString16 DOMStorageArea::Key(unsigned index) {
 118   if (is_shutdown_)
 119     return base::NullableString16();
 120   InitialImportIfNeeded();
 121   return map_->Key(index);
 122 }
 123
 124 base::NullableString16 DOMStorageArea::GetItem(const base::string16& key) {
 125   if (is_shutdown_)
 126     return base::NullableString16();
 127   InitialImportIfNeeded();
 128   return map_->GetItem(key);
 129 }
 130
 131 bool DOMStorageArea::SetItem(const base::string16& key,
 132                              const base::string16& value,
 133                              base::NullableString16* old_value) {
 134   if (is_shutdown_)
 135     return false;
 136   InitialImportIfNeeded();
 137   if (!map_->HasOneRef())
 138     map_ = map_->DeepCopy();
 139   bool success = map_->SetItem(key, value, old_value);
 140   if (success && backing_) {
 141     CommitBatch* commit_batch = CreateCommitBatchIfNeeded();
 142     commit_batch->changed_values[key] = base::NullableString16(value, false);
 143   }
 144   return success;
 145 }
 146
 147 bool DOMStorageArea::RemoveItem(const base::string16& key,
 148                                 base::string16* old_value) {
 149   if (is_shutdown_)
 150     return false;
 151   InitialImportIfNeeded();
 152   if (!map_->HasOneRef())
 153     map_ = map_->DeepCopy();
 154   bool success = map_->RemoveItem(key, old_value);
 155   if (success && backing_) {
 156     CommitBatch* commit_batch = CreateCommitBatchIfNeeded();
 157     commit_batch->changed_values[key] = base::NullableString16();
 158   }
 159   return success;
 160 }
 161
 162 bool DOMStorageArea::Clear() {
 163   if (is_shutdown_)
 164     return false;
 165   InitialImportIfNeeded();
 166   if (map_->Length() == 0)
 167     return false;
 168
 169   map_ = new DOMStorageMap(kPerStorageAreaQuota +
 170                            kPerStorageAreaOverQuotaAllowance);
 171
 172   if (backing_) {
 173     CommitBatch* commit_batch = CreateCommitBatchIfNeeded();
 174     commit_batch->clear_all_first = true;
 175     commit_batch->changed_values.clear();
 176   }
 177
 178   return true;
 179 }
 180
 181 void DOMStorageArea::FastClear() {
 182   // TODO(marja): Unify clearing localStorage and sessionStorage. The problem is
 183   // to make the following 3 to work together: 1) FastClear, 2) PurgeMemory and
 184   // 3) not creating events when clearing an empty area.
 185   if (is_shutdown_)
 186     return;
 187
 188   map_ = new DOMStorageMap(kPerStorageAreaQuota +
 189                            kPerStorageAreaOverQuotaAllowance);
 190   // This ensures no import will happen while we're waiting to clear the data
 191   // from the database. This mechanism fails if PurgeMemory is called.
 192   is_initial_import_done_ = true;
 193
 194   if (backing_) {
 195     CommitBatch* commit_batch = CreateCommitBatchIfNeeded();
 196     commit_batch->clear_all_first = true;
 197     commit_batch->changed_values.clear();
 198   }
 199 }
 200
 201 DOMStorageArea* DOMStorageArea::ShallowCopy(
 202     int64 destination_namespace_id,
 203     const std::string& destination_persistent_namespace_id) {
 204   DCHECK_NE(kLocalStorageNamespaceId, namespace_id_);
 205   DCHECK_NE(kLocalStorageNamespaceId, destination_namespace_id);
 206
 207   DOMStorageArea* copy = new DOMStorageArea(
 208       destination_namespace_id, destination_persistent_namespace_id, origin_,
 209       session_storage_backing_.get(), task_runner_.get());
 210   copy->map_ = map_;
 211   copy->is_shutdown_ = is_shutdown_;
 212   copy->is_initial_import_done_ = true;
 213
 214   // All the uncommitted changes to this area need to happen before the actual
 215   // shallow copy is made (scheduled by the upper layer). Another OnCommitTimer
 216   // call might be in the event queue at this point, but it's handled gracefully
 217   // when it fires.
 218   if (commit_batch_)
 219     OnCommitTimer();
 220   return copy;
 221 }
 222
 223 bool DOMStorageArea::HasUncommittedChanges() const {
 224   DCHECK(!is_shutdown_);
 225   return commit_batch_.get() || commit_batches_in_flight_;
 226 }
 227
 228 void DOMStorageArea::DeleteOrigin() {
 229   DCHECK(!is_shutdown_);
 230   // This function shouldn't be called for sessionStorage.
 231   DCHECK(!session_storage_backing_.get());
 232   if (HasUncommittedChanges()) {
 233     // TODO(michaeln): This logically deletes the data immediately,
 234     // and in a matter of a second, deletes the rows from the backing
 235     // database file, but the file itself will linger until shutdown
 236     // or purge time. Ideally, this should delete the file more
 237     // quickly.
 238     Clear();
 239     return;
 240   }
 241   map_ = new DOMStorageMap(kPerStorageAreaQuota +
 242                            kPerStorageAreaOverQuotaAllowance);
 243   if (backing_) {
 244     is_initial_import_done_ = false;
 245     backing_->Reset();
 246     backing_->DeleteFiles();
 247   }
 248 }
 249
 250 void DOMStorageArea::PurgeMemory() {
 251   DCHECK(!is_shutdown_);
 252   // Purging sessionStorage is not supported; it won't work with FastClear.
 253   DCHECK(!session_storage_backing_.get());
 254   if (!is_initial_import_done_ ||  // We're not using any memory.
 255       !backing_.get() ||  // We can't purge anything.
 256       HasUncommittedChanges())  // We leave things alone with changes pending.
 257     return;
 258
 259   // Drop the in memory cache, we'll reload when needed.
 260   is_initial_import_done_ = false;
 261   map_ = new DOMStorageMap(kPerStorageAreaQuota +
 262                            kPerStorageAreaOverQuotaAllowance);
 263
 264   // Recreate the database object, this frees up the open sqlite connection
 265   // and its page cache.
 266   backing_->Reset();
 267 }
 268
 269 void DOMStorageArea::Shutdown() {
 270   DCHECK(!is_shutdown_);
 271   is_shutdown_ = true;
 272   map_ = NULL;
 273   if (!backing_)
 274     return;
 275
 276   bool success = task_runner_->PostShutdownBlockingTask(
 277       FROM_HERE,
 278       DOMStorageTaskRunner::COMMIT_SEQUENCE,
 279       base::Bind(&DOMStorageArea::ShutdownInCommitSequence, this));
 280   DCHECK(success);
 281 }
 282
 283 void DOMStorageArea::InitialImportIfNeeded() {
 284   if (is_initial_import_done_)
 285     return;
 286
 287   DCHECK(backing_.get());
 288
 289   base::TimeTicks before = base::TimeTicks::Now();
 290   DOMStorageValuesMap initial_values;
 291   backing_->ReadAllValues(&initial_values);
 292   map_->SwapValues(&initial_values);
 293   is_initial_import_done_ = true;
 294   base::TimeDelta time_to_import = base::TimeTicks::Now() - before;
 295   UMA_HISTOGRAM_TIMES("LocalStorage.BrowserTimeToPrimeLocalStorage",
 296                       time_to_import);
 297
 298   size_t local_storage_size_kb = map_->bytes_used() / 1024;
 299   // Track localStorage size, from 0-6MB. Note that the maximum size should be
 300   // 5MB, but we add some slop since we want to make sure the max size is always
 301   // above what we see in practice, since histograms can't change.
 302   UMA_HISTOGRAM_CUSTOM_COUNTS("LocalStorage.BrowserLocalStorageSizeInKB",
 303                               local_storage_size_kb,
 304                               0, 6 * 1024, 50);
 305   if (local_storage_size_kb < 100) {
 306     UMA_HISTOGRAM_TIMES(
 307         "LocalStorage.BrowserTimeToPrimeLocalStorageUnder100KB",
 308         time_to_import);
 309   } else if (local_storage_size_kb < 1000) {
 310     UMA_HISTOGRAM_TIMES(
 311         "LocalStorage.BrowserTimeToPrimeLocalStorage100KBTo1MB",
 312         time_to_import);
 313   } else {
 314     UMA_HISTOGRAM_TIMES(
 315         "LocalStorage.BrowserTimeToPrimeLocalStorage1MBTo5MB",
 316         time_to_import);
 317   }
 318 }
 319
 320 DOMStorageArea::CommitBatch* DOMStorageArea::CreateCommitBatchIfNeeded() {
 321   DCHECK(!is_shutdown_);
 322   if (!commit_batch_) {
 323     commit_batch_.reset(new CommitBatch());
 324
 325     // Start a timer to commit any changes that accrue in the batch, but only if
 326     // no commits are currently in flight. In that case the timer will be
 327     // started after the commits have happened.
 328     if (!commit_batches_in_flight_) {
 329       task_runner_->PostDelayedTask(
 330           FROM_HERE,
 331           base::Bind(&DOMStorageArea::OnCommitTimer, this),
 332           base::TimeDelta::FromSeconds(kCommitTimerSeconds));
 333     }
 334   }
 335   return commit_batch_.get();
 336 }
 337
 338 void DOMStorageArea::OnCommitTimer() {
 339   if (is_shutdown_)
 340     return;
 341
 342   DCHECK(backing_.get());
 343
 344   // It's possible that there is nothing to commit, since a shallow copy occured
 345   // before the timer fired.
 346   if (!commit_batch_)
 347     return;
 348
 349   // This method executes on the primary sequence, we schedule
 350   // a task for immediate execution on the commit sequence.
 351   DCHECK(task_runner_->IsRunningOnPrimarySequence());
 352   bool success = task_runner_->PostShutdownBlockingTask(
 353       FROM_HERE,
 354       DOMStorageTaskRunner::COMMIT_SEQUENCE,
 355       base::Bind(&DOMStorageArea::CommitChanges, this,
 356                  base::Owned(commit_batch_.release())));
 357   ++commit_batches_in_flight_;
 358   DCHECK(success);
 359 }
 360
 361 void DOMStorageArea::CommitChanges(const CommitBatch* commit_batch) {
 362   // This method executes on the commit sequence.
 363   DCHECK(task_runner_->IsRunningOnCommitSequence());
 364   backing_->CommitChanges(commit_batch->clear_all_first,
 365                                          commit_batch->changed_values);
 366   // TODO(michaeln): what if CommitChanges returns false (e.g., we're trying to
 367   // commit to a DB which is in an inconsistent state?)
 368   task_runner_->PostTask(
 369       FROM_HERE,
 370       base::Bind(&DOMStorageArea::OnCommitComplete, this));
 371 }
 372
 373 void DOMStorageArea::OnCommitComplete() {
 374   // We're back on the primary sequence in this method.
 375   DCHECK(task_runner_->IsRunningOnPrimarySequence());
 376   --commit_batches_in_flight_;
 377   if (is_shutdown_)
 378     return;
 379   if (commit_batch_.get() && !commit_batches_in_flight_) {
 380     // More changes have accrued, restart the timer.
 381     task_runner_->PostDelayedTask(
 382         FROM_HERE,
 383         base::Bind(&DOMStorageArea::OnCommitTimer, this),
 384         base::TimeDelta::FromSeconds(kCommitTimerSeconds));
 385   }
 386 }
 387
 388 void DOMStorageArea::ShutdownInCommitSequence() {
 389   // This method executes on the commit sequence.
 390   DCHECK(task_runner_->IsRunningOnCommitSequence());
 391   DCHECK(backing_.get());
 392   if (commit_batch_) {
 393     // Commit any changes that accrued prior to the timer firing.
 394     bool success = backing_->CommitChanges(
 395         commit_batch_->clear_all_first,
 396         commit_batch_->changed_values);
 397     DCHECK(success);
 398   }
 399   commit_batch_.reset();
 400   backing_.reset();
 401   session_storage_backing_ = NULL;
 402 }
 403
 404 }  // namespace content