1/* 2 * Copyright (C) 2006 Apple 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 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY 14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR 17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY 21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24 */ 25 26#include "config.h" 27#include "SQLiteTransaction.h" 28 29#include "SQLiteDatabase.h" 30 31#if PLATFORM(IOS) 32#include "SQLiteDatabaseTracker.h" 33#endif 34 35namespace WebCore { 36 37SQLiteTransaction::SQLiteTransaction(SQLiteDatabase& db, bool readOnly) 38 : m_db(db) 39 , m_inProgress(false) 40 , m_readOnly(readOnly) 41{ 42} 43 44SQLiteTransaction::~SQLiteTransaction() 45{ 46 if (m_inProgress) 47 rollback(); 48} 49 50void SQLiteTransaction::begin() 51{ 52 if (!m_inProgress) { 53 ASSERT(!m_db.m_transactionInProgress); 54 // Call BEGIN IMMEDIATE for a write transaction to acquire 55 // a RESERVED lock on the DB file. Otherwise, another write 56 // transaction (on another connection) could make changes 57 // to the same DB file before this transaction gets to execute 58 // any statements. If that happens, this transaction will fail. 59 // http://www.sqlite.org/lang_transaction.html 60 // http://www.sqlite.org/lockingv3.html#locking 61#if PLATFORM(IOS) 62 SQLiteDatabaseTracker::incrementTransactionInProgressCount(); 63#endif 64 if (m_readOnly) 65 m_inProgress = m_db.executeCommand("BEGIN"); 66 else 67 m_inProgress = m_db.executeCommand("BEGIN IMMEDIATE"); 68 m_db.m_transactionInProgress = m_inProgress; 69#if PLATFORM(IOS) 70 if (!m_inProgress) 71 SQLiteDatabaseTracker::decrementTransactionInProgressCount(); 72#endif 73 } 74} 75 76void SQLiteTransaction::commit() 77{ 78 if (m_inProgress) { 79 ASSERT(m_db.m_transactionInProgress); 80 m_inProgress = !m_db.executeCommand("COMMIT"); 81 m_db.m_transactionInProgress = m_inProgress; 82#if PLATFORM(IOS) 83 if (!m_inProgress) 84 SQLiteDatabaseTracker::decrementTransactionInProgressCount(); 85#endif 86 } 87} 88 89void SQLiteTransaction::rollback() 90{ 91 // We do not use the 'm_inProgress = m_db.executeCommand("ROLLBACK")' construct here, 92 // because m_inProgress should always be set to false after a ROLLBACK, and 93 // m_db.executeCommand("ROLLBACK") can sometimes harmlessly fail, thus returning 94 // a non-zero/true result (http://www.sqlite.org/lang_transaction.html). 95 if (m_inProgress) { 96 ASSERT(m_db.m_transactionInProgress); 97 m_db.executeCommand("ROLLBACK"); 98 m_inProgress = false; 99 m_db.m_transactionInProgress = false; 100#if PLATFORM(IOS) 101 SQLiteDatabaseTracker::decrementTransactionInProgressCount(); 102#endif 103 } 104} 105 106void SQLiteTransaction::stop() 107{ 108 if (m_inProgress) { 109 m_inProgress = false; 110 m_db.m_transactionInProgress = false; 111#if PLATFORM(IOS) 112 SQLiteDatabaseTracker::decrementTransactionInProgressCount(); 113#endif 114 } 115} 116 117bool SQLiteTransaction::wasRolledBackBySqlite() const 118{ 119 // According to http://www.sqlite.org/c3ref/get_autocommit.html, 120 // the auto-commit flag should be off in the middle of a transaction 121 return m_inProgress && m_db.isAutoCommitOn(); 122} 123 124} // namespace WebCore 125