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#ifndef ThreadIdentifierDataPthreads_h 32#define ThreadIdentifierDataPthreads_h 33 34#include <wtf/Threading.h> 35 36namespace WTF { 37 38// Holds ThreadIdentifier in the thread-specific storage and employs pthreads-specific 2-pass destruction to reliably remove 39// ThreadIdentifier from threadMap. It assumes regular ThreadSpecific types don't use multiple-pass destruction. 40class ThreadIdentifierData { 41 WTF_MAKE_NONCOPYABLE(ThreadIdentifierData); 42public: 43 ~ThreadIdentifierData(); 44 45 // One time initialization for this class as a whole. 46 // This method must be called before initialize() and it is not thread-safe. 47 static void initializeOnce(); 48 49 // Creates and puts an instance of ThreadIdentifierData into thread-specific storage. 50 static void initialize(ThreadIdentifier identifier); 51 52 // Returns 0 if thread-specific storage was not initialized. 53 static ThreadIdentifier identifier(); 54 55private: 56 ThreadIdentifierData(ThreadIdentifier identifier) 57 : m_identifier(identifier) 58 , m_isDestroyedOnce(false) 59 { 60 } 61 62 // This thread-specific destructor is called 2 times when thread terminates: 63 // - first, when all the other thread-specific destructors are called, it simply remembers it was 'destroyed once' 64 // and re-sets itself into the thread-specific slot to make Pthreads to call it again later. 65 // - second, after all thread-specific destructors were invoked, it gets called again - this time, we remove the 66 // ThreadIdentifier from the threadMap, completing the cleanup. 67 static void destruct(void* data); 68 69 ThreadIdentifier m_identifier; 70 bool m_isDestroyedOnce; 71 static pthread_key_t m_key; 72}; 73 74} // namespace WTF 75 76#endif // ThreadIdentifierDataPthreads_h 77 78 79