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| 1 // Copyright (c) 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/indexed_db/leveldb/leveldb_transaction.h" | |
| 6 | |
| 7 #include "base/logging.h" | |
| 8 #include "content/browser/indexed_db/leveldb/leveldb_database.h" | |
| 9 #include "content/browser/indexed_db/leveldb/leveldb_slice.h" | |
| 10 #include "content/browser/indexed_db/leveldb/leveldb_write_batch.h" | |
| 11 #include "third_party/leveldatabase/src/include/leveldb/db.h" | |
| 12 | |
| 13 namespace content { | |
| 14 | |
| 15 scoped_refptr<LevelDBTransaction> LevelDBTransaction::Create( | |
| 16 LevelDBDatabase* db) { | |
| 17 return make_scoped_refptr(new LevelDBTransaction(db)); | |
| 18 } | |
| 19 | |
| 20 LevelDBTransaction::LevelDBTransaction(LevelDBDatabase* db) | |
| 21 : db_(db), snapshot_(db), comparator_(db->Comparator()), finished_(false) { | |
| 22 tree_.abstractor().comparator_ = comparator_; | |
| 23 } | |
| 24 | |
| 25 LevelDBTransaction::AVLTreeNode::AVLTreeNode() {} | |
| 26 LevelDBTransaction::AVLTreeNode::~AVLTreeNode() {} | |
| 27 | |
| 28 void LevelDBTransaction::ClearTree() { | |
| 29 TreeType::Iterator iterator; | |
| 30 iterator.start_iter_least(tree_); | |
| 31 | |
| 32 std::vector<AVLTreeNode*> nodes; | |
| 33 | |
| 34 while (*iterator) { | |
| 35 nodes.push_back(*iterator); | |
| 36 ++iterator; | |
| 37 } | |
| 38 tree_.purge(); | |
| 39 | |
| 40 for (size_t i = 0; i < nodes.size(); ++i) | |
| 41 delete nodes[i]; | |
| 42 } | |
| 43 | |
| 44 LevelDBTransaction::~LevelDBTransaction() { ClearTree(); } | |
| 45 | |
| 46 static void InitVector(const LevelDBSlice& slice, std::vector<char>* vector) { | |
| 47 vector->clear(); | |
| 48 vector->insert(vector->end(), slice.begin(), slice.end()); | |
| 49 } | |
| 50 | |
| 51 void LevelDBTransaction::Set(const LevelDBSlice& key, | |
| 52 const std::vector<char>& value, | |
| 53 bool deleted) { | |
| 54 DCHECK(!finished_); | |
| 55 bool new_node = false; | |
| 56 AVLTreeNode* node = tree_.search(key); | |
| 57 | |
| 58 if (!node) { | |
| 59 node = new AVLTreeNode; | |
| 60 InitVector(key, &node->key); | |
| 61 tree_.insert(node); | |
| 62 new_node = true; | |
| 63 } | |
| 64 node->value = value; | |
| 65 node->deleted = deleted; | |
| 66 | |
| 67 if (new_node) | |
| 68 NotifyIteratorsOfTreeChange(); | |
| 69 } | |
| 70 | |
| 71 void LevelDBTransaction::Put(const LevelDBSlice& key, | |
| 72 const std::vector<char>& value) { | |
| 73 Set(key, value, false); | |
| 74 } | |
| 75 | |
| 76 void LevelDBTransaction::Remove(const LevelDBSlice& key) { | |
| 77 Set(key, std::vector<char>(), true); | |
| 78 } | |
| 79 | |
| 80 bool LevelDBTransaction::Get(const LevelDBSlice& key, | |
| 81 std::vector<char>& value, | |
| 82 bool& found) { | |
| 83 found = false; | |
| 84 DCHECK(!finished_); | |
| 85 AVLTreeNode* node = tree_.search(key); | |
| 86 | |
| 87 if (node) { | |
| 88 if (node->deleted) | |
| 89 return true; | |
| 90 | |
| 91 value = node->value; | |
| 92 found = true; | |
| 93 return true; | |
| 94 } | |
| 95 | |
| 96 bool ok = db_->Get(key, value, found, &snapshot_); | |
| 97 if (!ok) { | |
| 98 DCHECK(!found); | |
| 99 return false; | |
| 100 } | |
| 101 return true; | |
| 102 } | |
| 103 | |
| 104 bool LevelDBTransaction::Commit() { | |
| 105 DCHECK(!finished_); | |
| 106 | |
| 107 if (tree_.is_empty()) { | |
| 108 finished_ = true; | |
| 109 return true; | |
| 110 } | |
| 111 | |
| 112 scoped_ptr<LevelDBWriteBatch> write_batch = LevelDBWriteBatch::Create(); | |
| 113 | |
| 114 TreeType::Iterator iterator; | |
| 115 iterator.start_iter_least(tree_); | |
| 116 | |
| 117 while (*iterator) { | |
| 118 AVLTreeNode* node = *iterator; | |
| 119 if (!node->deleted) | |
| 120 write_batch->Put(LevelDBSlice(node->key), LevelDBSlice(node->value)); | |
| 121 else | |
| 122 write_batch->Remove(LevelDBSlice(node->key)); | |
| 123 ++iterator; | |
| 124 } | |
| 125 | |
| 126 if (!db_->Write(*write_batch)) | |
| 127 return false; | |
| 128 | |
| 129 ClearTree(); | |
| 130 finished_ = true; | |
| 131 return true; | |
| 132 } | |
| 133 | |
| 134 void LevelDBTransaction::Rollback() { | |
| 135 DCHECK(!finished_); | |
| 136 finished_ = true; | |
| 137 ClearTree(); | |
| 138 } | |
| 139 | |
| 140 scoped_ptr<LevelDBIterator> LevelDBTransaction::CreateIterator() { | |
| 141 return TransactionIterator::Create(this).PassAs<LevelDBIterator>(); | |
| 142 } | |
| 143 | |
| 144 scoped_ptr<LevelDBTransaction::TreeIterator> | |
| 145 LevelDBTransaction::TreeIterator::Create(LevelDBTransaction* transaction) { | |
| 146 return make_scoped_ptr(new TreeIterator(transaction)); | |
| 147 } | |
| 148 | |
| 149 bool LevelDBTransaction::TreeIterator::IsValid() const { return !!*iterator_; } | |
| 150 | |
| 151 void LevelDBTransaction::TreeIterator::SeekToLast() { | |
| 152 iterator_.start_iter_greatest(*tree_); | |
| 153 if (IsValid()) | |
| 154 key_ = (*iterator_)->key; | |
| 155 } | |
| 156 | |
| 157 void LevelDBTransaction::TreeIterator::Seek(const LevelDBSlice& target) { | |
| 158 iterator_.start_iter(*tree_, target, TreeType::EQUAL); | |
| 159 if (!IsValid()) | |
| 160 iterator_.start_iter(*tree_, target, TreeType::GREATER); | |
| 161 | |
| 162 if (IsValid()) | |
| 163 key_ = (*iterator_)->key; | |
| 164 } | |
| 165 | |
| 166 void LevelDBTransaction::TreeIterator::Next() { | |
| 167 DCHECK(IsValid()); | |
| 168 ++iterator_; | |
| 169 if (IsValid()) { | |
| 170 DCHECK(transaction_->comparator_->Compare(LevelDBSlice((*iterator_)->key), | |
| 171 LevelDBSlice(key_)) > | |
| 172 0); | |
| 173 (void) transaction_; | |
| 174 key_ = (*iterator_)->key; | |
| 175 } | |
| 176 } | |
| 177 | |
| 178 void LevelDBTransaction::TreeIterator::Prev() { | |
| 179 DCHECK(IsValid()); | |
| 180 --iterator_; | |
| 181 if (IsValid()) { | |
| 182 DCHECK(tree_->abstractor().comparator_->Compare( | |
| 183 LevelDBSlice((*iterator_)->key), LevelDBSlice(key_)) < | |
| 184 0); | |
| 185 key_ = (*iterator_)->key; | |
| 186 } | |
| 187 } | |
| 188 | |
| 189 LevelDBSlice LevelDBTransaction::TreeIterator::Key() const { | |
| 190 DCHECK(IsValid()); | |
| 191 return LevelDBSlice(key_); | |
| 192 } | |
| 193 | |
| 194 LevelDBSlice LevelDBTransaction::TreeIterator::Value() const { | |
| 195 DCHECK(IsValid()); | |
| 196 DCHECK(!IsDeleted()); | |
| 197 return LevelDBSlice((*iterator_)->value); | |
| 198 } | |
| 199 | |
| 200 bool LevelDBTransaction::TreeIterator::IsDeleted() const { | |
| 201 DCHECK(IsValid()); | |
| 202 return (*iterator_)->deleted; | |
| 203 } | |
| 204 | |
| 205 void LevelDBTransaction::TreeIterator::Reset() { | |
| 206 DCHECK(IsValid()); | |
| 207 iterator_.start_iter(*tree_, LevelDBSlice(key_), TreeType::EQUAL); | |
| 208 DCHECK(IsValid()); | |
| 209 } | |
| 210 | |
| 211 LevelDBTransaction::TreeIterator::~TreeIterator() {} | |
| 212 | |
| 213 LevelDBTransaction::TreeIterator::TreeIterator(LevelDBTransaction* transaction) | |
| 214 : tree_(&transaction->tree_), transaction_(transaction) {} | |
| 215 | |
| 216 scoped_ptr<LevelDBTransaction::TransactionIterator> | |
| 217 LevelDBTransaction::TransactionIterator::Create( | |
| 218 scoped_refptr<LevelDBTransaction> transaction) { | |
| 219 return make_scoped_ptr(new TransactionIterator(transaction)); | |
| 220 } | |
| 221 | |
| 222 LevelDBTransaction::TransactionIterator::TransactionIterator( | |
| 223 scoped_refptr<LevelDBTransaction> transaction) | |
| 224 : transaction_(transaction), | |
| 225 comparator_(transaction_->comparator_), | |
| 226 tree_iterator_(TreeIterator::Create(transaction_.get())), | |
| 227 db_iterator_(transaction_->db_->CreateIterator(&transaction_->snapshot_)), | |
| 228 current_(0), | |
| 229 direction_(FORWARD), | |
| 230 tree_changed_(false) { | |
| 231 transaction_->RegisterIterator(this); | |
| 232 } | |
| 233 | |
| 234 LevelDBTransaction::TransactionIterator::~TransactionIterator() { | |
| 235 transaction_->UnregisterIterator(this); | |
| 236 } | |
| 237 | |
| 238 bool LevelDBTransaction::TransactionIterator::IsValid() const { | |
| 239 return !!current_; | |
| 240 } | |
| 241 | |
| 242 void LevelDBTransaction::TransactionIterator::SeekToLast() { | |
| 243 tree_iterator_->SeekToLast(); | |
| 244 db_iterator_->SeekToLast(); | |
| 245 direction_ = REVERSE; | |
| 246 | |
| 247 HandleConflictsAndDeletes(); | |
| 248 SetCurrentIteratorToLargestKey(); | |
| 249 } | |
| 250 | |
| 251 void LevelDBTransaction::TransactionIterator::Seek(const LevelDBSlice& target) { | |
| 252 tree_iterator_->Seek(target); | |
| 253 db_iterator_->Seek(target); | |
| 254 direction_ = FORWARD; | |
| 255 | |
| 256 HandleConflictsAndDeletes(); | |
| 257 SetCurrentIteratorToSmallestKey(); | |
| 258 } | |
| 259 | |
| 260 void LevelDBTransaction::TransactionIterator::Next() { | |
| 261 DCHECK(IsValid()); | |
| 262 if (tree_changed_) | |
| 263 RefreshTreeIterator(); | |
| 264 | |
| 265 if (direction_ != FORWARD) { | |
| 266 // Ensure the non-current iterator is positioned after Key(). | |
| 267 | |
| 268 LevelDBIterator* non_current = | |
| 269 (current_ == db_iterator_.get()) ? tree_iterator_.get() | |
| 270 : db_iterator_.get(); | |
| 271 | |
| 272 non_current->Seek(Key()); | |
| 273 if (non_current->IsValid() && | |
| 274 !comparator_->Compare(non_current->Key(), Key())) | |
| 275 non_current->Next(); // Take an extra step so the non-current key is | |
| 276 // strictly greater than Key(). | |
| 277 | |
| 278 DCHECK(!non_current->IsValid() || | |
| 279 comparator_->Compare(non_current->Key(), Key()) > 0); | |
| 280 | |
| 281 direction_ = FORWARD; | |
| 282 } | |
| 283 | |
| 284 current_->Next(); | |
| 285 HandleConflictsAndDeletes(); | |
| 286 SetCurrentIteratorToSmallestKey(); | |
| 287 } | |
| 288 | |
| 289 void LevelDBTransaction::TransactionIterator::Prev() { | |
| 290 DCHECK(IsValid()); | |
| 291 if (tree_changed_) | |
| 292 RefreshTreeIterator(); | |
| 293 | |
| 294 if (direction_ != REVERSE) { | |
| 295 // Ensure the non-current iterator is positioned before Key(). | |
| 296 | |
| 297 LevelDBIterator* non_current = | |
| 298 (current_ == db_iterator_.get()) ? tree_iterator_.get() | |
| 299 : db_iterator_.get(); | |
| 300 | |
| 301 non_current->Seek(Key()); | |
| 302 if (non_current->IsValid()) { | |
| 303 // Iterator is at first entry >= Key(). | |
| 304 // Step back once to entry < key. | |
| 305 // This is why we don't check for the keys being the same before | |
| 306 // stepping, like we do in Next() above. | |
| 307 non_current->Prev(); | |
| 308 } else { | |
| 309 non_current->SeekToLast(); // Iterator has no entries >= Key(). Position | |
| 310 // at last entry. | |
| 311 } | |
| 312 DCHECK(!non_current->IsValid() || | |
| 313 comparator_->Compare(non_current->Key(), Key()) < 0); | |
| 314 | |
| 315 direction_ = REVERSE; | |
| 316 } | |
| 317 | |
| 318 current_->Prev(); | |
| 319 HandleConflictsAndDeletes(); | |
| 320 SetCurrentIteratorToLargestKey(); | |
| 321 } | |
| 322 | |
| 323 LevelDBSlice LevelDBTransaction::TransactionIterator::Key() const { | |
| 324 DCHECK(IsValid()); | |
| 325 if (tree_changed_) | |
| 326 RefreshTreeIterator(); | |
| 327 return current_->Key(); | |
| 328 } | |
| 329 | |
| 330 LevelDBSlice LevelDBTransaction::TransactionIterator::Value() const { | |
| 331 DCHECK(IsValid()); | |
| 332 if (tree_changed_) | |
| 333 RefreshTreeIterator(); | |
| 334 return current_->Value(); | |
| 335 } | |
| 336 | |
| 337 void LevelDBTransaction::TransactionIterator::TreeChanged() { | |
| 338 tree_changed_ = true; | |
| 339 } | |
| 340 | |
| 341 void LevelDBTransaction::TransactionIterator::RefreshTreeIterator() const { | |
| 342 DCHECK(tree_changed_); | |
| 343 | |
| 344 tree_changed_ = false; | |
| 345 | |
| 346 if (tree_iterator_->IsValid() && tree_iterator_.get() == current_) { | |
| 347 tree_iterator_->Reset(); | |
| 348 return; | |
| 349 } | |
| 350 | |
| 351 if (db_iterator_->IsValid()) { | |
| 352 | |
| 353 // There could be new nodes in the tree that we should iterate over. | |
| 354 | |
| 355 if (direction_ == FORWARD) { | |
| 356 // Try to seek tree iterator to something greater than the db iterator. | |
| 357 tree_iterator_->Seek(db_iterator_->Key()); | |
| 358 if (tree_iterator_->IsValid() && | |
| 359 !comparator_->Compare(tree_iterator_->Key(), db_iterator_->Key())) | |
| 360 tree_iterator_->Next(); // If equal, take another step so the tree | |
| 361 // iterator is strictly greater. | |
| 362 } else { | |
| 363 // If going backward, seek to a key less than the db iterator. | |
| 364 DCHECK_EQ(REVERSE, direction_); | |
| 365 tree_iterator_->Seek(db_iterator_->Key()); | |
| 366 if (tree_iterator_->IsValid()) | |
| 367 tree_iterator_->Prev(); | |
| 368 } | |
| 369 } | |
| 370 } | |
| 371 | |
| 372 bool LevelDBTransaction::TransactionIterator::TreeIteratorIsLower() const { | |
| 373 return comparator_->Compare(tree_iterator_->Key(), db_iterator_->Key()) < 0; | |
| 374 } | |
| 375 | |
| 376 bool LevelDBTransaction::TransactionIterator::TreeIteratorIsHigher() const { | |
| 377 return comparator_->Compare(tree_iterator_->Key(), db_iterator_->Key()) > 0; | |
| 378 } | |
| 379 | |
| 380 void LevelDBTransaction::TransactionIterator::HandleConflictsAndDeletes() { | |
| 381 bool loop = true; | |
| 382 | |
| 383 while (loop) { | |
| 384 loop = false; | |
| 385 | |
| 386 if (tree_iterator_->IsValid() && db_iterator_->IsValid() && | |
| 387 !comparator_->Compare(tree_iterator_->Key(), db_iterator_->Key())) { | |
| 388 // For equal keys, the tree iterator takes precedence, so move the | |
| 389 // database iterator another step. | |
| 390 if (direction_ == FORWARD) | |
| 391 db_iterator_->Next(); | |
| 392 else | |
| 393 db_iterator_->Prev(); | |
| 394 } | |
| 395 | |
| 396 // Skip over delete markers in the tree iterator until it catches up with | |
| 397 // the db iterator. | |
| 398 if (tree_iterator_->IsValid() && tree_iterator_->IsDeleted()) { | |
| 399 if (direction_ == FORWARD && | |
| 400 (!db_iterator_->IsValid() || TreeIteratorIsLower())) { | |
| 401 tree_iterator_->Next(); | |
| 402 loop = true; | |
| 403 } else if (direction_ == REVERSE && | |
| 404 (!db_iterator_->IsValid() || TreeIteratorIsHigher())) { | |
| 405 tree_iterator_->Prev(); | |
| 406 loop = true; | |
| 407 } | |
| 408 } | |
| 409 } | |
| 410 } | |
| 411 | |
| 412 void | |
| 413 LevelDBTransaction::TransactionIterator::SetCurrentIteratorToSmallestKey() { | |
| 414 LevelDBIterator* smallest = 0; | |
| 415 | |
| 416 if (tree_iterator_->IsValid()) | |
| 417 smallest = tree_iterator_.get(); | |
| 418 | |
| 419 if (db_iterator_->IsValid()) { | |
| 420 if (!smallest || | |
| 421 comparator_->Compare(db_iterator_->Key(), smallest->Key()) < 0) | |
| 422 smallest = db_iterator_.get(); | |
| 423 } | |
| 424 | |
| 425 current_ = smallest; | |
| 426 } | |
| 427 | |
| 428 void LevelDBTransaction::TransactionIterator::SetCurrentIteratorToLargestKey() { | |
| 429 LevelDBIterator* largest = 0; | |
| 430 | |
| 431 if (tree_iterator_->IsValid()) | |
| 432 largest = tree_iterator_.get(); | |
| 433 | |
| 434 if (db_iterator_->IsValid()) { | |
| 435 if (!largest || | |
| 436 comparator_->Compare(db_iterator_->Key(), largest->Key()) > 0) | |
| 437 largest = db_iterator_.get(); | |
| 438 } | |
| 439 | |
| 440 current_ = largest; | |
| 441 } | |
| 442 | |
| 443 void LevelDBTransaction::RegisterIterator(TransactionIterator* iterator) { | |
| 444 DCHECK(iterators_.find(iterator) == iterators_.end()); | |
| 445 iterators_.insert(iterator); | |
| 446 } | |
| 447 | |
| 448 void LevelDBTransaction::UnregisterIterator(TransactionIterator* iterator) { | |
| 449 DCHECK(iterators_.find(iterator) != iterators_.end()); | |
| 450 iterators_.erase(iterator); | |
| 451 } | |
| 452 | |
| 453 void LevelDBTransaction::NotifyIteratorsOfTreeChange() { | |
| 454 for (std::set<TransactionIterator*>::iterator i = iterators_.begin(); | |
| 455 i != iterators_.end(); | |
| 456 ++i) { | |
| 457 TransactionIterator* transaction_iterator = *i; | |
| 458 transaction_iterator->TreeChanged(); | |
| 459 } | |
| 460 } | |
| 461 | |
| 462 scoped_ptr<LevelDBWriteOnlyTransaction> LevelDBWriteOnlyTransaction::Create( | |
| 463 LevelDBDatabase* db) { | |
| 464 return make_scoped_ptr(new LevelDBWriteOnlyTransaction(db)); | |
| 465 } | |
| 466 | |
| 467 LevelDBWriteOnlyTransaction::LevelDBWriteOnlyTransaction(LevelDBDatabase* db) | |
| 468 : db_(db), write_batch_(LevelDBWriteBatch::Create()), finished_(false) {} | |
| 469 | |
| 470 LevelDBWriteOnlyTransaction::~LevelDBWriteOnlyTransaction() { | |
| 471 write_batch_->Clear(); | |
| 472 } | |
| 473 | |
| 474 void LevelDBWriteOnlyTransaction::Remove(const LevelDBSlice& key) { | |
| 475 DCHECK(!finished_); | |
| 476 write_batch_->Remove(key); | |
| 477 } | |
| 478 | |
| 479 bool LevelDBWriteOnlyTransaction::Commit() { | |
| 480 DCHECK(!finished_); | |
| 481 | |
| 482 if (!db_->Write(*write_batch_)) | |
| 483 return false; | |
| 484 | |
| 485 finished_ = true; | |
| 486 write_batch_->Clear(); | |
| 487 return true; | |
| 488 } | |
| 489 | |
| 490 } // namespace content | |
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Chromium Code Reviews
Issue 15659013:
Revert "Migrate the IndexedDB backend from Blink to Chromium" (Closed)
Base URL: svn://svn.chromium.org/chrome/trunk/src