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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 "platform/TaskSynchronizer.h"
     31 
     32 #include "heap/ThreadState.h"
     33 
     34 namespace WebCore {
     35 
     36 TaskSynchronizer::TaskSynchronizer()
     37     : m_taskCompleted(false)
     38 #ifndef NDEBUG
     39     , m_hasCheckedForTermination(false)
     40 #endif
     41 {
     42 }
     43 
     44 void TaskSynchronizer::waitForTaskCompletion()
     45 {
     46     if (ThreadState::current()) {
     47         // Prevent the deadlock between park request by other threads and blocking
     48         // by m_synchronousCondition.
     49         ThreadState::SafePointScope scope(ThreadState::HeapPointersOnStack);
     50         waitForTaskCompletionInternal();
     51     } else {
     52         // If this thread is already detached, we no longer need to enter a safe point scope.
     53         waitForTaskCompletionInternal();
     54     }
     55 }
     56 
     57 void TaskSynchronizer::waitForTaskCompletionInternal()
     58 {
     59     m_synchronousMutex.lock();
     60     while (!m_taskCompleted)
     61         m_synchronousCondition.wait(m_synchronousMutex);
     62     m_synchronousMutex.unlock();
     63 }
     64 
     65 void TaskSynchronizer::taskCompleted()
     66 {
     67     m_synchronousMutex.lock();
     68     m_taskCompleted = true;
     69     m_synchronousCondition.signal();
     70     m_synchronousMutex.unlock();
     71 }
     72 
     73 } // namespace WebCore
     74