1 /* 2 * Copyright (C) 2011 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 ThreadRestrictionVerifier_h 32 #define ThreadRestrictionVerifier_h 33 34 #ifndef NDEBUG 35 36 #include "wtf/Assertions.h" 37 #include "wtf/Threading.h" 38 39 namespace WTF { 40 41 // Verifies that a class is used in a way that respects its lack of thread-safety. 42 // The default mode is to verify that the object will only be used on a single thread. The 43 // thread gets captured when setShared(true) is called. 44 // The mode may be changed by calling useMutexMode (or turnOffVerification). 45 class ThreadRestrictionVerifier { 46 public: ThreadRestrictionVerifier()47 ThreadRestrictionVerifier() 48 : m_shared(false) 49 , m_owningThread(0) 50 { 51 } 52 53 // Indicates that the object may (or may not) be owned by more than one place. setShared(bool shared)54 void setShared(bool shared) 55 { 56 #if ASSERT_ENABLED 57 bool previouslyShared = m_shared; 58 #endif 59 m_shared = shared; 60 61 if (!m_shared) 62 return; 63 64 ASSERT(shared != previouslyShared); 65 // Capture the current thread to verify that subsequent ref/deref happen on this thread. 66 m_owningThread = currentThread(); 67 } 68 69 // Is it OK to use the object at this moment on the current thread? isSafeToUse()70 bool isSafeToUse() const 71 { 72 if (!m_shared) 73 return true; 74 75 return m_owningThread == currentThread(); 76 } 77 78 private: 79 bool m_shared; 80 81 // Used by SingleThreadVerificationMode 82 ThreadIdentifier m_owningThread; 83 }; 84 85 } 86 87 #endif // !NDEBUG 88 #endif // ThreadRestrictionVerifier_h 89