1 /* 2 * Copyright (C) 2006 Apple Computer, 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 COMPUTER, 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 COMPUTER, 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 #if ENABLE(DATABASE) 30 31 #include "SQLiteDatabase.h" 32 33 namespace WebCore { 34 35 SQLiteTransaction::SQLiteTransaction(SQLiteDatabase& db, bool readOnly) 36 : m_db(db) 37 , m_inProgress(false) 38 , m_readOnly(readOnly) 39 { 40 } 41 42 SQLiteTransaction::~SQLiteTransaction() 43 { 44 if (m_inProgress) 45 rollback(); 46 } 47 48 void SQLiteTransaction::begin() 49 { 50 if (!m_inProgress) { 51 ASSERT(!m_db.m_transactionInProgress); 52 // Call BEGIN IMMEDIATE for a write transaction to acquire 53 // a RESERVED lock on the DB file. Otherwise, another write 54 // transaction (on another connection) could make changes 55 // to the same DB file before this transaction gets to execute 56 // any statements. If that happens, this transaction will fail. 57 // http://www.sqlite.org/lang_transaction.html 58 // http://www.sqlite.org/lockingv3.html#locking 59 if (m_readOnly) 60 m_inProgress = m_db.executeCommand("BEGIN"); 61 else 62 m_inProgress = m_db.executeCommand("BEGIN IMMEDIATE"); 63 m_db.m_transactionInProgress = m_inProgress; 64 } 65 } 66 67 void SQLiteTransaction::commit() 68 { 69 if (m_inProgress) { 70 ASSERT(m_db.m_transactionInProgress); 71 m_inProgress = !m_db.executeCommand("COMMIT"); 72 m_db.m_transactionInProgress = m_inProgress; 73 } 74 } 75 76 void SQLiteTransaction::rollback() 77 { 78 // We do not use the 'm_inProgress = m_db.executeCommand("ROLLBACK")' construct here, 79 // because m_inProgress should always be set to false after a ROLLBACK, and 80 // m_db.executeCommand("ROLLBACK") can sometimes harmlessly fail, thus returning 81 // a non-zero/true result (http://www.sqlite.org/lang_transaction.html). 82 if (m_inProgress) { 83 ASSERT(m_db.m_transactionInProgress); 84 m_db.executeCommand("ROLLBACK"); 85 m_inProgress = false; 86 m_db.m_transactionInProgress = false; 87 } 88 } 89 90 void SQLiteTransaction::stop() 91 { 92 if (m_inProgress) { 93 m_inProgress = false; 94 m_db.m_transactionInProgress = false; 95 } 96 } 97 98 bool SQLiteTransaction::wasRolledBackBySqlite() const 99 { 100 // According to http://www.sqlite.org/c3ref/get_autocommit.html, 101 // the auto-commit flag should be off in the middle of a transaction 102 return m_inProgress && m_db.isAutoCommitOn(); 103 } 104 105 } // namespace WebCore 106 #endif // ENABLE(DATABASE) 107
