1/*
2 * Copyright (C) 2010 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
6 * are met:
7 *
8 * 1.  Redistributions of source code must retain the above copyright
9 *     notice, this list of conditions and the following disclaimer.
10 * 2.  Redistributions in binary form must reproduce the above copyright
11 *     notice, this list of conditions and the following disclaimer in the
12 *     documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
15 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
16 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
17 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
18 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
19 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
20 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
21 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#include "config.h"
27#include "IDBTransactionBackendImpl.h"
28
29#if ENABLE(INDEXED_DATABASE)
30
31#include "IDBBackingStore.h"
32#include "IDBDatabaseBackendImpl.h"
33#include "IDBDatabaseException.h"
34#include "IDBTransactionCoordinator.h"
35
36namespace WebCore {
37
38PassRefPtr<IDBTransactionBackendImpl> IDBTransactionBackendImpl::create(DOMStringList* objectStores, unsigned short mode, IDBDatabaseBackendImpl* database)
39{
40    return adoptRef(new IDBTransactionBackendImpl(objectStores, mode, database));
41}
42
43IDBTransactionBackendImpl::IDBTransactionBackendImpl(DOMStringList* objectStores, unsigned short mode, IDBDatabaseBackendImpl* database)
44    : m_objectStoreNames(objectStores)
45    , m_mode(mode)
46    , m_state(Unused)
47    , m_database(database)
48    , m_transaction(database->backingStore()->createTransaction())
49    , m_taskTimer(this, &IDBTransactionBackendImpl::taskTimerFired)
50    , m_taskEventTimer(this, &IDBTransactionBackendImpl::taskEventTimerFired)
51    , m_pendingEvents(0)
52{
53    ASSERT(m_objectStoreNames);
54    m_database->transactionCoordinator()->didCreateTransaction(this);
55}
56
57IDBTransactionBackendImpl::~IDBTransactionBackendImpl()
58{
59    // It shouldn't be possible for this object to get deleted until it's either complete or aborted.
60    ASSERT(m_state == Finished);
61}
62
63PassRefPtr<IDBObjectStoreBackendInterface> IDBTransactionBackendImpl::objectStore(const String& name, ExceptionCode& ec)
64{
65    if (m_state == Finished) {
66        ec = IDBDatabaseException::NOT_ALLOWED_ERR;
67        return 0;
68    }
69
70    // Does a linear search, but it really shouldn't be that slow in practice.
71    if (!m_objectStoreNames->isEmpty() && !m_objectStoreNames->contains(name)) {
72        ec = IDBDatabaseException::NOT_FOUND_ERR;
73        return 0;
74    }
75
76    RefPtr<IDBObjectStoreBackendInterface> objectStore = m_database->objectStore(name);
77    // FIXME: This is only necessary right now beacuse a setVersion transaction could modify things
78    //        between its creation (where another check occurs) and the .objectStore call.
79    //        There's a bug to make this impossible in the spec. When we make it impossible here, we
80    //        can remove this check.
81    if (!objectStore) {
82        ec = IDBDatabaseException::NOT_FOUND_ERR;
83        return 0;
84    }
85    return objectStore.release();
86}
87
88bool IDBTransactionBackendImpl::scheduleTask(PassOwnPtr<ScriptExecutionContext::Task> task, PassOwnPtr<ScriptExecutionContext::Task> abortTask)
89{
90    if (m_state == Finished)
91        return false;
92
93    m_taskQueue.append(task);
94    if (abortTask)
95        m_abortTaskQueue.prepend(abortTask);
96
97    if (m_state == Unused)
98        start();
99
100    return true;
101}
102
103void IDBTransactionBackendImpl::abort()
104{
105    if (m_state == Finished)
106        return;
107
108    // The last reference to this object may be released while performing the
109    // abort steps below. We therefore take a self reference to keep ourselves
110    // alive while executing this method.
111    RefPtr<IDBTransactionBackendImpl> self(this);
112
113    m_state = Finished;
114    m_taskTimer.stop();
115    m_taskEventTimer.stop();
116    m_transaction->rollback();
117
118    // Run the abort tasks, if any.
119    while (!m_abortTaskQueue.isEmpty()) {
120        OwnPtr<ScriptExecutionContext::Task> task(m_abortTaskQueue.first().release());
121        m_abortTaskQueue.removeFirst();
122        task->performTask(0);
123    }
124
125    m_callbacks->onAbort();
126    m_database->transactionCoordinator()->didFinishTransaction(this);
127    ASSERT(!m_database->transactionCoordinator()->isActive(this));
128    m_database = 0;
129}
130
131void IDBTransactionBackendImpl::didCompleteTaskEvents()
132{
133    if (m_state == Finished)
134        return;
135
136    ASSERT(m_state == Running);
137    ASSERT(m_pendingEvents);
138    m_pendingEvents--;
139
140    if (!m_taskEventTimer.isActive())
141        m_taskEventTimer.startOneShot(0);
142}
143
144void IDBTransactionBackendImpl::run()
145{
146    ASSERT(m_state == StartPending || m_state == Running);
147    ASSERT(!m_taskTimer.isActive());
148
149    m_taskTimer.startOneShot(0);
150}
151
152void IDBTransactionBackendImpl::start()
153{
154    ASSERT(m_state == Unused);
155
156    m_state = StartPending;
157    m_database->transactionCoordinator()->didStartTransaction(this);
158}
159
160void IDBTransactionBackendImpl::commit()
161{
162    // The last reference to this object may be released while performing the
163    // commit steps below. We therefore take a self reference to keep ourselves
164    // alive while executing this method.
165    RefPtr<IDBTransactionBackendImpl> self(this);
166    ASSERT(m_state == Running);
167
168    m_state = Finished;
169    m_transaction->commit();
170    m_callbacks->onComplete();
171    m_database->transactionCoordinator()->didFinishTransaction(this);
172    m_database = 0;
173}
174
175void IDBTransactionBackendImpl::taskTimerFired(Timer<IDBTransactionBackendImpl>*)
176{
177    ASSERT(!m_taskQueue.isEmpty());
178
179    if (m_state == StartPending) {
180        m_transaction->begin();
181        m_state = Running;
182    }
183
184    TaskQueue queue;
185    queue.swap(m_taskQueue);
186    while (!queue.isEmpty() && m_state != Finished) {
187        ASSERT(m_state == Running);
188        OwnPtr<ScriptExecutionContext::Task> task(queue.first().release());
189        queue.removeFirst();
190        m_pendingEvents++;
191        task->performTask(0);
192    }
193}
194
195void IDBTransactionBackendImpl::taskEventTimerFired(Timer<IDBTransactionBackendImpl>*)
196{
197    ASSERT(m_state == Running);
198
199    if (!m_pendingEvents && m_taskQueue.isEmpty()) {
200        // The last task event has completed and the task
201        // queue is empty. Commit the transaction.
202        commit();
203        return;
204    }
205
206    // We are still waiting for other events to complete. However,
207    // the task queue is non-empty and the timer is inactive.
208    // We can therfore schedule the timer again.
209    if (!m_taskQueue.isEmpty() && !m_taskTimer.isActive())
210        m_taskTimer.startOneShot(0);
211}
212
213};
214
215#endif // ENABLE(INDEXED_DATABASE)
216