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_FAMILY)
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_FAMILY)
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_FAMILY)
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_FAMILY)
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_FAMILY)
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_FAMILY)
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