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      1 /*
      2  * Copyright (C) 2007, 2008 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 "DatabaseThread.h"
     31 
     32 #if ENABLE(DATABASE)
     33 
     34 #include "AutodrainedPool.h"
     35 #include "Database.h"
     36 #include "DatabaseTask.h"
     37 #include "Logging.h"
     38 #include "SQLTransactionClient.h"
     39 #include "SQLTransactionCoordinator.h"
     40 #include <wtf/UnusedParam.h>
     41 
     42 namespace WebCore {
     43 
     44 DatabaseThread::DatabaseThread()
     45     : m_threadID(0)
     46     , m_transactionClient(adoptPtr(new SQLTransactionClient()))
     47     , m_transactionCoordinator(adoptPtr(new SQLTransactionCoordinator()))
     48     , m_cleanupSync(0)
     49 {
     50     m_selfRef = this;
     51 }
     52 
     53 DatabaseThread::~DatabaseThread()
     54 {
     55     // FIXME: Any cleanup required here?  Since the thread deletes itself after running its detached course, I don't think so.  Lets be sure.
     56     ASSERT(terminationRequested());
     57 }
     58 
     59 bool DatabaseThread::start()
     60 {
     61     MutexLocker lock(m_threadCreationMutex);
     62 
     63     if (m_threadID)
     64         return true;
     65 
     66     m_threadID = createThread(DatabaseThread::databaseThreadStart, this, "WebCore: Database");
     67 
     68     return m_threadID;
     69 }
     70 
     71 void DatabaseThread::requestTermination(DatabaseTaskSynchronizer *cleanupSync)
     72 {
     73     ASSERT(!m_cleanupSync);
     74     m_cleanupSync = cleanupSync;
     75     LOG(StorageAPI, "DatabaseThread %p was asked to terminate\n", this);
     76     m_queue.kill();
     77 }
     78 
     79 bool DatabaseThread::terminationRequested(DatabaseTaskSynchronizer* taskSynchronizer) const
     80 {
     81 #ifndef NDEBUG
     82     if (taskSynchronizer)
     83         taskSynchronizer->setHasCheckedForTermination();
     84 #else
     85     UNUSED_PARAM(taskSynchronizer);
     86 #endif
     87 
     88     return m_queue.killed();
     89 }
     90 
     91 void* DatabaseThread::databaseThreadStart(void* vDatabaseThread)
     92 {
     93     DatabaseThread* dbThread = static_cast<DatabaseThread*>(vDatabaseThread);
     94     return dbThread->databaseThread();
     95 }
     96 
     97 void* DatabaseThread::databaseThread()
     98 {
     99     {
    100         // Wait for DatabaseThread::start() to complete.
    101         MutexLocker lock(m_threadCreationMutex);
    102         LOG(StorageAPI, "Started DatabaseThread %p", this);
    103     }
    104 
    105     AutodrainedPool pool;
    106     while (OwnPtr<DatabaseTask> task = m_queue.waitForMessage()) {
    107         task->performTask();
    108         pool.cycle();
    109     }
    110 
    111     // Clean up the list of all pending transactions on this database thread
    112     m_transactionCoordinator->shutdown();
    113 
    114     LOG(StorageAPI, "About to detach thread %i and clear the ref to DatabaseThread %p, which currently has %i ref(s)", m_threadID, this, refCount());
    115 
    116     // 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
    117     // inconsistent or locked state.
    118     if (m_openDatabaseSet.size() > 0) {
    119         // As the call to close will modify the original set, we must take a copy to iterate over.
    120         DatabaseSet openSetCopy;
    121         openSetCopy.swap(m_openDatabaseSet);
    122         DatabaseSet::iterator end = openSetCopy.end();
    123         for (DatabaseSet::iterator it = openSetCopy.begin(); it != end; ++it)
    124             (*it)->close();
    125     }
    126 
    127     // Detach the thread so its resources are no longer of any concern to anyone else
    128     detachThread(m_threadID);
    129 
    130     DatabaseTaskSynchronizer* cleanupSync = m_cleanupSync;
    131 
    132     // Clear the self refptr, possibly resulting in deletion
    133     m_selfRef = 0;
    134 
    135     if (cleanupSync) // Someone wanted to know when we were done cleaning up.
    136         cleanupSync->taskCompleted();
    137 
    138     return 0;
    139 }
    140 
    141 void DatabaseThread::recordDatabaseOpen(Database* database)
    142 {
    143     ASSERT(currentThread() == m_threadID);
    144     ASSERT(database);
    145     ASSERT(!m_openDatabaseSet.contains(database));
    146     m_openDatabaseSet.add(database);
    147 }
    148 
    149 void DatabaseThread::recordDatabaseClosed(Database* database)
    150 {
    151     ASSERT(currentThread() == m_threadID);
    152     ASSERT(database);
    153     ASSERT(m_queue.killed() || m_openDatabaseSet.contains(database));
    154     m_openDatabaseSet.remove(database);
    155 }
    156 
    157 void DatabaseThread::scheduleTask(PassOwnPtr<DatabaseTask> task)
    158 {
    159     ASSERT(!task->hasSynchronizer() || task->hasCheckedForTermination());
    160     m_queue.append(task);
    161 }
    162 
    163 void DatabaseThread::scheduleImmediateTask(PassOwnPtr<DatabaseTask> task)
    164 {
    165     ASSERT(!task->hasSynchronizer() || task->hasCheckedForTermination());
    166     m_queue.prepend(task);
    167 }
    168 
    169 class SameDatabasePredicate {
    170 public:
    171     SameDatabasePredicate(const Database* database) : m_database(database) { }
    172     bool operator()(DatabaseTask* task) const { return task->database() == m_database; }
    173 private:
    174     const Database* m_database;
    175 };
    176 
    177 void DatabaseThread::unscheduleDatabaseTasks(Database* database)
    178 {
    179     // Note that the thread loop is running, so some tasks for the database
    180     // may still be executed. This is unavoidable.
    181     SameDatabasePredicate predicate(database);
    182     m_queue.removeIf(predicate);
    183 }
    184 } // namespace WebCore
    185 #endif
    186