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      1 /*
      2  * Copyright (C) 2009 Google 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 are
      6  * met:
      7  *
      8  *     * Redistributions of source code must retain the above copyright
      9  * notice, this list of conditions and the following disclaimer.
     10  *     * Redistributions in binary form must reproduce the above
     11  * copyright notice, this list of conditions and the following disclaimer
     12  * in the documentation and/or other materials provided with the
     13  * distribution.
     14  *     * Neither the name of Google Inc. nor the names of its
     15  * contributors may be used to endorse or promote products derived from
     16  * this software without specific prior written permission.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     29  */
     30 
     31 #include "config.h"
     32 
     33 #if USE(PTHREADS)
     34 
     35 #include "ThreadIdentifierDataPthreads.h"
     36 
     37 #include "Threading.h"
     38 
     39 namespace WTF {
     40 
     41 pthread_key_t ThreadIdentifierData::m_key;
     42 
     43 void clearPthreadHandleForIdentifier(ThreadIdentifier);
     44 
     45 ThreadIdentifierData::~ThreadIdentifierData()
     46 {
     47     clearPthreadHandleForIdentifier(m_identifier);
     48 }
     49 
     50 ThreadIdentifier ThreadIdentifierData::identifier()
     51 {
     52     initializeKeyOnce();
     53     ThreadIdentifierData* threadIdentifierData = static_cast<ThreadIdentifierData*>(pthread_getspecific(m_key));
     54 
     55     return threadIdentifierData ? threadIdentifierData->m_identifier : 0;
     56 }
     57 
     58 void ThreadIdentifierData::initialize(ThreadIdentifier id)
     59 {
     60     ASSERT(!identifier());
     61 
     62     initializeKeyOnce();
     63     pthread_setspecific(m_key, new ThreadIdentifierData(id));
     64 }
     65 
     66 void ThreadIdentifierData::destruct(void* data)
     67 {
     68     ThreadIdentifierData* threadIdentifierData = static_cast<ThreadIdentifierData*>(data);
     69     ASSERT(threadIdentifierData);
     70 
     71     if (threadIdentifierData->m_isDestroyedOnce) {
     72         delete threadIdentifierData;
     73         return;
     74     }
     75 
     76     threadIdentifierData->m_isDestroyedOnce = true;
     77     // Re-setting the value for key causes another destruct() call after all other thread-specific destructors were called.
     78     pthread_setspecific(m_key, threadIdentifierData);
     79 }
     80 
     81 void ThreadIdentifierData::initializeKeyOnceHelper()
     82 {
     83     if (pthread_key_create(&m_key, destruct))
     84         CRASH();
     85 }
     86 
     87 void ThreadIdentifierData::initializeKeyOnce()
     88 {
     89     static pthread_once_t onceControl = PTHREAD_ONCE_INIT;
     90     if (pthread_once(&onceControl, initializeKeyOnceHelper))
     91         CRASH();
     92 }
     93 
     94 } // namespace WTF
     95 
     96 #endif // USE(PTHREADS)
     97 
     98