1 /* 2 * Copyright (C) 2013 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 ThreadState_h 32 #define ThreadState_h 33 34 #include "wtf/HashSet.h" 35 #include "wtf/ThreadSpecific.h" 36 #include "wtf/Threading.h" 37 38 namespace WebCore { 39 40 class ThreadState { 41 public: 42 // Initialize threading infrastructure. Should be called from the main 43 // thread. 44 static void init(intptr_t* startOfStack); 45 static void shutdown(); 46 47 // Associate ThreadState object with the current thread. After this 48 // call thread can start using the garbage collected heap infrastructure. 49 // It also has to periodically check for safepoints. 50 static void attach(intptr_t* startOfStack); 51 52 // Disassociate attached ThreadState from the current thread. The thread 53 // can no longer use the garbage collected heap after this call. 54 static void detach(); 55 current()56 static ThreadState* current() { return **s_threadSpecific; } mainThreadState()57 static ThreadState* mainThreadState() 58 { 59 return reinterpret_cast<ThreadState*>(s_mainThreadStateStorage); 60 } 61 isMainThread()62 static bool isMainThread() { return current() == mainThreadState(); } 63 checkThread()64 inline void checkThread() const 65 { 66 ASSERT(m_thread == currentThread()); 67 } 68 69 private: 70 explicit ThreadState(intptr_t* startOfStack); 71 ~ThreadState(); 72 73 typedef HashSet<ThreadState*> AttachedThreadStateSet; 74 static AttachedThreadStateSet& attachedThreads(); 75 76 static WTF::ThreadSpecific<ThreadState*>* s_threadSpecific; 77 78 // We can't create a static member of type ThreadState here 79 // because it will introduce global constructor and destructor. 80 // We would like to manage lifetime of the ThreadState attached 81 // to the main thread explicitly instead and still use normal 82 // constructor and destructor for the ThreadState class. 83 // For this we reserve static storage for the main ThreadState 84 // and lazily construct ThreadState in it using placement new. 85 static uint8_t s_mainThreadStateStorage[]; 86 87 ThreadIdentifier m_thread; 88 intptr_t* m_startOfStack; 89 }; 90 91 } 92 93 #endif // ThreadState_h 94