Source/modules/webdatabase/DatabaseThread.cpp

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#include "config.h"
#include "modules/webdatabase/DatabaseThread.h"

#include "modules/webdatabase/Database.h"
#include "modules/webdatabase/DatabaseTask.h"
#include "modules/webdatabase/SQLTransactionClient.h"
#include "modules/webdatabase/SQLTransactionCoordinator.h"
#include "platform/Logging.h"
#include "platform/heap/glue/MessageLoopInterruptor.h"
#include "platform/heap/glue/PendingGCRunner.h"
#include "public/platform/Platform.h"

namespace blink {

DatabaseThread::DatabaseThread()
    : m_transactionClient(adoptPtr(new SQLTransactionClient()))
    , m_transactionCoordinator(new SQLTransactionCoordinator())
    , m_cleanupSync(0)
    , m_terminationRequested(false)
{
}

DatabaseThread::~DatabaseThread()
{
    ASSERT(m_openDatabaseSet.isEmpty());
    ASSERT(!m_thread);
}

void DatabaseThread::trace(Visitor* visitor)
{
    visitor->trace(m_openDatabaseSet);
    visitor->trace(m_transactionCoordinator);
}

void DatabaseThread::start()
{
    if (m_thread)
        return;
    m_thread = WebThreadSupportingGC::create("WebCore: Database");
    m_thread->postTask(new Task(WTF::bind(&DatabaseThread::setupDatabaseThread, this)));
}

void DatabaseThread::setupDatabaseThread()
{
    m_thread->attachGC();
}

void DatabaseThread::terminate()
{
    TaskSynchronizer sync;
    {
        MutexLocker lock(m_terminationRequestedMutex);
        ASSERT(!m_terminationRequested);
        m_terminationRequested = true;
        m_cleanupSync = &sync;
        WTF_LOG(StorageAPI, "DatabaseThread %p was asked to terminate\n", this);
        m_thread->postTask(new Task(WTF::bind(&DatabaseThread::cleanupDatabaseThread, this)));
    }
    sync.waitForTaskCompletion();
    // The WebThread destructor blocks until all the tasks of the database
    // thread are processed. However, it shouldn't block at all because
    // the database thread has already finished processing the cleanup task.
    m_thread.clear();
}

bool DatabaseThread::terminationRequested() const
{
    MutexLocker lock(m_terminationRequestedMutex);
    return m_terminationRequested;
}

void DatabaseThread::cleanupDatabaseThread()
{
    WTF_LOG(StorageAPI, "Cleaning up DatabaseThread %p", this);

    // Clean up the list of all pending transactions on this database thread
    m_transactionCoordinator->shutdown();

    // 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
    // inconsistent or locked state.
    if (m_openDatabaseSet.size() > 0) {
        // As the call to close will modify the original set, we must take a copy to iterate over.
        HeapHashSet<Member<Database> > openSetCopy;
        openSetCopy.swap(m_openDatabaseSet);
        HeapHashSet<Member<Database> >::iterator end = openSetCopy.end();
        for (HeapHashSet<Member<Database> >::iterator it = openSetCopy.begin(); it != end; ++it)
            (*it)->close();
    }
    m_openDatabaseSet.clear();

    m_thread->postTask(new Task(WTF::bind(&DatabaseThread::cleanupDatabaseThreadCompleted, this)));
}

void DatabaseThread::cleanupDatabaseThreadCompleted()
{
    m_thread->detachGC();
    if (m_cleanupSync) // Someone wanted to know when we were done cleaning up.
        m_cleanupSync->taskCompleted();
}

void DatabaseThread::recordDatabaseOpen(Database* database)
{
    ASSERT(isDatabaseThread());
    ASSERT(database);
    ASSERT(!m_openDatabaseSet.contains(database));
    MutexLocker lock(m_terminationRequestedMutex);
    if (!m_terminationRequested)
        m_openDatabaseSet.add(database);
}

void DatabaseThread::recordDatabaseClosed(Database* database)
{
    ASSERT(isDatabaseThread());
    ASSERT(database);
    ASSERT(m_terminationRequested || m_openDatabaseSet.contains(database));
    m_openDatabaseSet.remove(database);
}

bool DatabaseThread::isDatabaseOpen(Database* database)
{
    ASSERT(isDatabaseThread());
    ASSERT(database);
    MutexLocker lock(m_terminationRequestedMutex);
    return !m_terminationRequested && m_openDatabaseSet.contains(database);
}

void DatabaseThread::scheduleTask(PassOwnPtr<DatabaseTask> task)
{
    ASSERT(m_thread);
    ASSERT(!terminationRequested());
    // WebThread takes ownership of the task.
    m_thread->postTask(task.leakPtr());
}

} // namespace blink