1 /*
2 * Copyright (C) 2009 Google 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 are
6 * met:
7 *
8 * * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * * Redistributions in binary form must reproduce the above
11 * copyright notice, this list of conditions and the following disclaimer
12 * in the documentation and/or other materials provided with the
13 * distribution.
14 * * Neither the name of Google Inc. nor the names of its
15 * contributors may be used to endorse or promote products derived from
16 * this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31 #include "config.h"
32 #include "SQLTransactionCoordinator.h"
33
34 #if ENABLE(DATABASE)
35
36 #include "CString.h"
37 #include "Database.h"
38 #include "SQLTransaction.h"
39 #include <wtf/Deque.h>
40 #include <wtf/HashMap.h>
41 #include <wtf/HashSet.h>
42 #include <wtf/RefPtr.h>
43
44 namespace WebCore {
45
getDatabaseIdentifier(SQLTransaction * transaction)46 static String getDatabaseIdentifier(SQLTransaction* transaction)
47 {
48 Database* database = transaction->database();
49 ASSERT(database);
50 return database->stringIdentifier();
51 }
52
processPendingTransactions(CoordinationInfo & info)53 void SQLTransactionCoordinator::processPendingTransactions(CoordinationInfo& info)
54 {
55 if (info.activeWriteTransaction || info.pendingTransactions.isEmpty())
56 return;
57
58 RefPtr<SQLTransaction> firstPendingTransaction = info.pendingTransactions.first();
59 if (firstPendingTransaction->isReadOnly()) {
60 do {
61 firstPendingTransaction = info.pendingTransactions.first();
62 info.pendingTransactions.removeFirst();
63 info.activeReadTransactions.add(firstPendingTransaction);
64 firstPendingTransaction->lockAcquired();
65 } while (!info.pendingTransactions.isEmpty() && info.pendingTransactions.first()->isReadOnly());
66 } else if (info.activeReadTransactions.isEmpty()) {
67 info.pendingTransactions.removeFirst();
68 info.activeWriteTransaction = firstPendingTransaction;
69 firstPendingTransaction->lockAcquired();
70 }
71 }
72
acquireLock(SQLTransaction * transaction)73 void SQLTransactionCoordinator::acquireLock(SQLTransaction* transaction)
74 {
75 String dbIdentifier = getDatabaseIdentifier(transaction);
76
77 CoordinationInfoMap::iterator coordinationInfoIterator = m_coordinationInfoMap.find(dbIdentifier);
78 if (coordinationInfoIterator == m_coordinationInfoMap.end()) {
79 // No pending transactions for this DB
80 coordinationInfoIterator = m_coordinationInfoMap.add(dbIdentifier, CoordinationInfo()).first;
81 }
82
83 CoordinationInfo& info = coordinationInfoIterator->second;
84 info.pendingTransactions.append(transaction);
85 processPendingTransactions(info);
86 }
87
releaseLock(SQLTransaction * transaction)88 void SQLTransactionCoordinator::releaseLock(SQLTransaction* transaction)
89 {
90 if (m_coordinationInfoMap.isEmpty())
91 return;
92
93 String dbIdentifier = getDatabaseIdentifier(transaction);
94
95 CoordinationInfoMap::iterator coordinationInfoIterator = m_coordinationInfoMap.find(dbIdentifier);
96 ASSERT(coordinationInfoIterator != m_coordinationInfoMap.end());
97 CoordinationInfo& info = coordinationInfoIterator->second;
98
99 if (transaction->isReadOnly()) {
100 ASSERT(info.activeReadTransactions.contains(transaction));
101 info.activeReadTransactions.remove(transaction);
102 } else {
103 ASSERT(info.activeWriteTransaction == transaction);
104 info.activeWriteTransaction = 0;
105 }
106
107 processPendingTransactions(info);
108 }
109
shutdown()110 void SQLTransactionCoordinator::shutdown()
111 {
112 // Notify all transactions in progress that the database thread is shutting down
113 for (CoordinationInfoMap::iterator coordinationInfoIterator = m_coordinationInfoMap.begin();
114 coordinationInfoIterator != m_coordinationInfoMap.end(); ++coordinationInfoIterator) {
115 CoordinationInfo& info = coordinationInfoIterator->second;
116 if (info.activeWriteTransaction)
117 info.activeWriteTransaction->notifyDatabaseThreadIsShuttingDown();
118 for (HashSet<RefPtr<SQLTransaction> >::iterator activeReadTransactionsIterator =
119 info.activeReadTransactions.begin();
120 activeReadTransactionsIterator != info.activeReadTransactions.end();
121 ++activeReadTransactionsIterator) {
122 (*activeReadTransactionsIterator)->notifyDatabaseThreadIsShuttingDown();
123 }
124 }
125
126 // Clean up all pending transactions for all databases
127 m_coordinationInfoMap.clear();
128 }
129
130 } // namespace WebCore
131
132 #endif // ENABLE(DATABASE)
133