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