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
SQLiteTransaction(SQLiteDatabase & db,bool readOnly)35 SQLiteTransaction::SQLiteTransaction(SQLiteDatabase& db, bool readOnly)
36 : m_db(db)
37 , m_inProgress(false)
38 , m_readOnly(readOnly)
39 {
40 }
41
~SQLiteTransaction()42 SQLiteTransaction::~SQLiteTransaction()
43 {
44 if (m_inProgress)
45 rollback();
46 }
47
begin()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
commit()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
rollback()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
stop()90 void SQLiteTransaction::stop()
91 {
92 if (m_inProgress) {
93 m_inProgress = false;
94 m_db.m_transactionInProgress = false;
95 }
96 }
97
wasRolledBackBySqlite() const98 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