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      1 /*
      2  * Copyright (C) 2007, 2008, 2013 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  *
      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  * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
     14  *     its contributors may be used to endorse or promote products derived
     15  *     from this software without specific prior written permission.
     16  *
     17  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
     18  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     19  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     20  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
     21  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
     22  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     23  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
     24  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     27  */
     28 
     29 #include "config.h"
     30 #include "modules/webdatabase/DatabaseThread.h"
     31 
     32 #include "modules/webdatabase/Database.h"
     33 #include "modules/webdatabase/DatabaseTask.h"
     34 #include "modules/webdatabase/SQLTransactionClient.h"
     35 #include "modules/webdatabase/SQLTransactionCoordinator.h"
     36 #include "platform/Logging.h"
     37 #include "platform/heap/glue/MessageLoopInterruptor.h"
     38 #include "platform/heap/glue/PendingGCRunner.h"
     39 #include "public/platform/Platform.h"
     40 
     41 namespace WebCore {
     42 
     43 DatabaseThread::DatabaseThread()
     44     : m_transactionClient(adoptPtr(new SQLTransactionClient()))
     45     , m_transactionCoordinator(adoptPtrWillBeNoop(new SQLTransactionCoordinator()))
     46     , m_cleanupSync(0)
     47     , m_terminationRequested(false)
     48 {
     49 }
     50 
     51 DatabaseThread::~DatabaseThread()
     52 {
     53     ASSERT(m_openDatabaseSet.isEmpty());
     54     // Oilpan: The database thread must have finished its cleanup tasks before
     55     // the following clear(). Otherwise, WebThread destructor blocks the caller
     56     // thread, and causes a deadlock with ThreadState cleanup.
     57     // DatabaseContext::stop() asks the database thread to close all of
     58     // databases, and wait until GC heap cleanup of the database thread. So we
     59     // can safely destruct WebThread here.
     60     m_thread.clear();
     61 }
     62 
     63 void DatabaseThread::trace(Visitor* visitor)
     64 {
     65     visitor->trace(m_openDatabaseSet);
     66     visitor->trace(m_transactionCoordinator);
     67 }
     68 
     69 void DatabaseThread::start()
     70 {
     71     if (m_thread)
     72         return;
     73     m_thread = adoptPtr(blink::Platform::current()->createThread("WebCore: Database"));
     74     m_thread->postTask(new Task(WTF::bind(&DatabaseThread::setupDatabaseThread, this)));
     75 }
     76 
     77 void DatabaseThread::setupDatabaseThread()
     78 {
     79     m_pendingGCRunner = adoptPtr(new PendingGCRunner);
     80     m_messageLoopInterruptor = adoptPtr(new MessageLoopInterruptor(m_thread.get()));
     81     m_thread->addTaskObserver(m_pendingGCRunner.get());
     82     ThreadState::attach();
     83     ThreadState::current()->addInterruptor(m_messageLoopInterruptor.get());
     84 }
     85 
     86 void DatabaseThread::requestTermination(TaskSynchronizer *cleanupSync)
     87 {
     88     MutexLocker lock(m_terminationRequestedMutex);
     89     ASSERT(!m_terminationRequested);
     90     m_terminationRequested = true;
     91     m_cleanupSync = cleanupSync;
     92     WTF_LOG(StorageAPI, "DatabaseThread %p was asked to terminate\n", this);
     93     m_thread->postTask(new Task(WTF::bind(&DatabaseThread::cleanupDatabaseThread, this)));
     94 }
     95 
     96 bool DatabaseThread::terminationRequested(TaskSynchronizer* taskSynchronizer) const
     97 {
     98 #ifndef NDEBUG
     99     if (taskSynchronizer)
    100         taskSynchronizer->setHasCheckedForTermination();
    101 #endif
    102 
    103     MutexLocker lock(m_terminationRequestedMutex);
    104     return m_terminationRequested;
    105 }
    106 
    107 void DatabaseThread::cleanupDatabaseThread()
    108 {
    109     WTF_LOG(StorageAPI, "Cleaning up DatabaseThread %p", this);
    110 
    111     // Clean up the list of all pending transactions on this database thread
    112     m_transactionCoordinator->shutdown();
    113 
    114     // Close the databases that we ran transactions on. This ensures that if any transactions are still open, they are rolled back and we don't leave the database in an
    115     // inconsistent or locked state.
    116     if (m_openDatabaseSet.size() > 0) {
    117         // As the call to close will modify the original set, we must take a copy to iterate over.
    118         WillBeHeapHashSet<RefPtrWillBeMember<DatabaseBackend> > openSetCopy;
    119         openSetCopy.swap(m_openDatabaseSet);
    120         WillBeHeapHashSet<RefPtrWillBeMember<DatabaseBackend> >::iterator end = openSetCopy.end();
    121         for (WillBeHeapHashSet<RefPtrWillBeMember<DatabaseBackend> >::iterator it = openSetCopy.begin(); it != end; ++it)
    122             (*it)->close();
    123     }
    124 
    125     m_thread->postTask(new Task(WTF::bind(&DatabaseThread::cleanupDatabaseThreadCompleted, this)));
    126 }
    127 
    128 void DatabaseThread::cleanupDatabaseThreadCompleted()
    129 {
    130     ThreadState::current()->removeInterruptor(m_messageLoopInterruptor.get());
    131     ThreadState::detach();
    132     // We need to unregister PendingGCRunner before finising this task to avoid
    133     // PendingGCRunner::didProcessTask accesses dead ThreadState.
    134     m_thread->removeTaskObserver(m_pendingGCRunner.get());
    135 
    136     if (m_cleanupSync) // Someone wanted to know when we were done cleaning up.
    137         m_cleanupSync->taskCompleted();
    138 }
    139 
    140 void DatabaseThread::recordDatabaseOpen(DatabaseBackend* database)
    141 {
    142     ASSERT(isDatabaseThread());
    143     ASSERT(database);
    144     ASSERT(!m_openDatabaseSet.contains(database));
    145     m_openDatabaseSet.add(database);
    146 }
    147 
    148 void DatabaseThread::recordDatabaseClosed(DatabaseBackend* database)
    149 {
    150     ASSERT(isDatabaseThread());
    151     ASSERT(database);
    152     ASSERT(m_terminationRequested || m_openDatabaseSet.contains(database));
    153     m_openDatabaseSet.remove(database);
    154 }
    155 
    156 bool DatabaseThread::isDatabaseOpen(DatabaseBackend* database)
    157 {
    158     ASSERT(isDatabaseThread());
    159     ASSERT(database);
    160     MutexLocker lock(m_terminationRequestedMutex);
    161     return !m_terminationRequested && m_openDatabaseSet.contains(database);
    162 }
    163 
    164 void DatabaseThread::scheduleTask(PassOwnPtr<DatabaseTask> task)
    165 {
    166     ASSERT(m_thread);
    167     ASSERT(!task->hasSynchronizer() || task->hasCheckedForTermination());
    168     // WebThread takes ownership of the task.
    169     m_thread->postTask(task.leakPtr());
    170 }
    171 
    172 } // namespace WebCore
    173