1/* 2 * Copyright (C) 2009 Google Inc. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions are 6 * met: 7 * 8 * * Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * * Redistributions in binary form must reproduce the above 11 * copyright notice, this list of conditions and the following disclaimer 12 * in the documentation and/or other materials provided with the 13 * distribution. 14 * * Neither the name of Google Inc. nor the names of its 15 * contributors may be used to endorse or promote products derived from 16 * this software without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 */ 30 31#include "config.h" 32#include "SQLTransactionCoordinator.h" 33 34#if ENABLE(DATABASE) 35 36#include "Database.h" 37#include "SQLTransaction.h" 38#include <wtf/Deque.h> 39#include <wtf/HashMap.h> 40#include <wtf/HashSet.h> 41#include <wtf/RefPtr.h> 42 43namespace WebCore { 44 45static String getDatabaseIdentifier(SQLTransaction* transaction) 46{ 47 Database* database = transaction->database(); 48 ASSERT(database); 49 return database->stringIdentifier(); 50} 51 52void SQLTransactionCoordinator::processPendingTransactions(CoordinationInfo& info) 53{ 54 if (info.activeWriteTransaction || info.pendingTransactions.isEmpty()) 55 return; 56 57 RefPtr<SQLTransaction> firstPendingTransaction = info.pendingTransactions.first(); 58 if (firstPendingTransaction->isReadOnly()) { 59 do { 60 firstPendingTransaction = info.pendingTransactions.takeFirst(); 61 info.activeReadTransactions.add(firstPendingTransaction); 62 firstPendingTransaction->lockAcquired(); 63 } while (!info.pendingTransactions.isEmpty() && info.pendingTransactions.first()->isReadOnly()); 64 } else if (info.activeReadTransactions.isEmpty()) { 65 info.pendingTransactions.removeFirst(); 66 info.activeWriteTransaction = firstPendingTransaction; 67 firstPendingTransaction->lockAcquired(); 68 } 69} 70 71void SQLTransactionCoordinator::acquireLock(SQLTransaction* transaction) 72{ 73 String dbIdentifier = getDatabaseIdentifier(transaction); 74 75 CoordinationInfoMap::iterator coordinationInfoIterator = m_coordinationInfoMap.find(dbIdentifier); 76 if (coordinationInfoIterator == m_coordinationInfoMap.end()) { 77 // No pending transactions for this DB 78 coordinationInfoIterator = m_coordinationInfoMap.add(dbIdentifier, CoordinationInfo()).first; 79 } 80 81 CoordinationInfo& info = coordinationInfoIterator->second; 82 info.pendingTransactions.append(transaction); 83 processPendingTransactions(info); 84} 85 86void SQLTransactionCoordinator::releaseLock(SQLTransaction* transaction) 87{ 88 if (m_coordinationInfoMap.isEmpty()) 89 return; 90 91 String dbIdentifier = getDatabaseIdentifier(transaction); 92 93 CoordinationInfoMap::iterator coordinationInfoIterator = m_coordinationInfoMap.find(dbIdentifier); 94 ASSERT(coordinationInfoIterator != m_coordinationInfoMap.end()); 95 CoordinationInfo& info = coordinationInfoIterator->second; 96 97 if (transaction->isReadOnly()) { 98 ASSERT(info.activeReadTransactions.contains(transaction)); 99 info.activeReadTransactions.remove(transaction); 100 } else { 101 ASSERT(info.activeWriteTransaction == transaction); 102 info.activeWriteTransaction = 0; 103 } 104 105 processPendingTransactions(info); 106} 107 108void SQLTransactionCoordinator::shutdown() 109{ 110 // Notify all transactions in progress that the database thread is shutting down 111 for (CoordinationInfoMap::iterator coordinationInfoIterator = m_coordinationInfoMap.begin(); 112 coordinationInfoIterator != m_coordinationInfoMap.end(); ++coordinationInfoIterator) { 113 CoordinationInfo& info = coordinationInfoIterator->second; 114 if (info.activeWriteTransaction) 115 info.activeWriteTransaction->notifyDatabaseThreadIsShuttingDown(); 116 for (HashSet<RefPtr<SQLTransaction> >::iterator activeReadTransactionsIterator = 117 info.activeReadTransactions.begin(); 118 activeReadTransactionsIterator != info.activeReadTransactions.end(); 119 ++activeReadTransactionsIterator) { 120 (*activeReadTransactionsIterator)->notifyDatabaseThreadIsShuttingDown(); 121 } 122 } 123 124 // Clean up all pending transactions for all databases 125 m_coordinationInfoMap.clear(); 126} 127 128} // namespace WebCore 129 130#endif // ENABLE(DATABASE) 131