third_party/WebKit/Source/platform/TaskSynchronizer.cpp

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