/* * Copyright (C) 2009 Google Inc. All rights reserved. * Copyright (C) 2017 Yusuke Suzuki <utatane.tea@gmail.com>. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are * met: * * * Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above * copyright notice, this list of conditions and the following disclaimer * in the documentation and/or other materials provided with the * distribution. * * Neither the name of Google Inc. nor the names of its * contributors may be used to endorse or promote products derived from * this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #pragma once #include <wtf/ThreadSpecific.h> #include <wtf/Threading.h> namespace WTF { // Holds Thread in the thread-specific storage. The destructor of this holder reliably destroy Thread. // For pthread, it employs pthreads-specific 2-pass destruction to reliably remove Thread. // For Windows, we use thread_local to defer thread holder destruction. It assumes regular ThreadSpecific // types don't use multiple-pass destruction. class ThreadHolder { WTF_MAKE_NONCOPYABLE(ThreadHolder); public: ~ThreadHolder(); // One time initialization for this class as a whole. // This method must be called before initialize() and it is not thread-safe. static void initializeOnce(); // Creates and puts an instance of ThreadHolder into thread-specific storage. #if OS(WINDOWS) static void initialize(Thread&, ThreadIdentifier); #else static void initialize(Thread&); #endif // Returns 0 if thread-specific storage was not initialized. static ThreadHolder* current(); Thread& thread() { return m_thread.get(); } #if OS(WINDOWS) static RefPtr<Thread> get(ThreadIdentifier); #endif private: ThreadHolder(Thread& thread) : m_thread(thread) , m_isDestroyedOnce(false) { } // This thread-specific destructor is called 2 times when thread terminates: // - first, when all the other thread-specific destructors are called, it simply remembers it was 'destroyed once' // and (1) re-sets itself into the thread-specific slot or (2) constructs thread local value to call it again later. // - second, after all thread-specific destructors were invoked, it gets called again - this time, we remove the // Thread from the threadMap, completing the cleanup. static void THREAD_SPECIFIC_CALL destruct(void* data); Ref<Thread> m_thread; bool m_isDestroyedOnce; static ThreadSpecificKey m_key; }; } // namespace WTF