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 #include "SQLiteDatabase.h"
30
31 namespace WebCore {
32
SQLiteTransaction(SQLiteDatabase & db,bool readOnly)33 SQLiteTransaction::SQLiteTransaction(SQLiteDatabase& db, bool readOnly)
34 : m_db(db)
35 , m_inProgress(false)
36 , m_readOnly(readOnly)
37 {
38 }
39
~SQLiteTransaction()40 SQLiteTransaction::~SQLiteTransaction()
41 {
42 if (m_inProgress)
43 rollback();
44 }
45
begin()46 void SQLiteTransaction::begin()
47 {
48 if (!m_inProgress) {
49 ASSERT(!m_db.m_transactionInProgress);
50 // Call BEGIN IMMEDIATE for a write transaction to acquire
51 // a RESERVED lock on the DB file. Otherwise, another write
52 // transaction (on another connection) could make changes
53 // to the same DB file before this transaction gets to execute
54 // any statements. If that happens, this transaction will fail.
55 // http://www.sqlite.org/lang_transaction.html
56 // http://www.sqlite.org/lockingv3.html#locking
57 if (m_readOnly)
58 m_inProgress = m_db.executeCommand("BEGIN");
59 else
60 m_inProgress = m_db.executeCommand("BEGIN IMMEDIATE");
61 m_db.m_transactionInProgress = m_inProgress;
62 }
63 }
64
commit()65 void SQLiteTransaction::commit()
66 {
67 if (m_inProgress) {
68 ASSERT(m_db.m_transactionInProgress);
69 m_inProgress = !m_db.executeCommand("COMMIT");
70 m_db.m_transactionInProgress = m_inProgress;
71 }
72 }
73
rollback()74 void SQLiteTransaction::rollback()
75 {
76 // We do not use the 'm_inProgress = m_db.executeCommand("ROLLBACK")' construct here,
77 // because m_inProgress should always be set to false after a ROLLBACK, and
78 // m_db.executeCommand("ROLLBACK") can sometimes harmlessly fail, thus returning
79 // a non-zero/true result (http://www.sqlite.org/lang_transaction.html).
80 if (m_inProgress) {
81 ASSERT(m_db.m_transactionInProgress);
82 m_db.executeCommand("ROLLBACK");
83 m_inProgress = false;
84 m_db.m_transactionInProgress = false;
85 }
86 }
87
stop()88 void SQLiteTransaction::stop()
89 {
90 if (m_inProgress) {
91 m_inProgress = false;
92 m_db.m_transactionInProgress = false;
93 }
94 }
95
wasRolledBackBySqlite() const96 bool SQLiteTransaction::wasRolledBackBySqlite() const
97 {
98 // According to http://www.sqlite.org/c3ref/get_autocommit.html,
99 // the auto-commit flag should be off in the middle of a transaction
100 return m_inProgress && m_db.isAutoCommitOn();
101 }
102
103 } // namespace WebCore
104