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/*
* Copyright (C) 2007, 2008, 2010 Apple Inc. All rights reserved.
* Copyright (C) 2007 Justin Haygood (jhaygood@reaktix.com)
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
* 3. Neither the name of Apple Computer, Inc. ("Apple") 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 APPLE AND ITS 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 APPLE OR ITS 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.
*/
#ifndef Threading_h
#define Threading_h
#include "wtf/Atomics.h"
#include "wtf/TypeTraits.h"
#include "wtf/WTFExport.h"
#include <stdint.h>
// For portability, we do not make use of C++11 thread-safe statics, as supported
// by some toolchains. Make use of double-checked locking to reduce overhead.
#define AtomicallyInitializedStaticReferenceInternal(T, name, initializer, LOCK, UNLOCK) \
/* Init to nullptr is thread-safe on all implementations. */ \
static void* name##Pointer = nullptr; \
if (!WTF::acquireLoad(&name##Pointer)) { \
LOCK; \
if (!WTF::acquireLoad(&name##Pointer)) { \
std::remove_const<T>::type* initializerResult = initializer; \
WTF::releaseStore(&name##Pointer, initializerResult); \
} \
UNLOCK; \
} \
T& name = *static_cast<T*>(name##Pointer)
// Uses system-wide default lock. This version cannot be used before
// WTF::initializeThreading() is called.
#define AtomicallyInitializedStaticReference(T, name, initializer) \
AtomicallyInitializedStaticReferenceInternal( \
T, name, initializer, \
WTF::lockAtomicallyInitializedStaticMutex(), \
WTF::unlockAtomicallyInitializedStaticMutex())
// Same as above but uses a given lock.
#define AtomicallyInitializedStaticReferenceWithLock(T, name, initializer, lockable) \
AtomicallyInitializedStaticReferenceInternal( \
T, name, initializer, lockable.lock(), lockable.unlock());
namespace WTF {
#if OS(WIN)
typedef uint32_t ThreadIdentifier;
#else
typedef intptr_t ThreadIdentifier;
#endif
WTF_EXPORT ThreadIdentifier currentThread();
WTF_EXPORT void lockAtomicallyInitializedStaticMutex();
WTF_EXPORT void unlockAtomicallyInitializedStaticMutex();
#if ENABLE(ASSERT)
WTF_EXPORT bool isAtomicallyInitializedStaticMutexLockHeld();
WTF_EXPORT bool isBeforeThreadCreated();
WTF_EXPORT void willCreateThread();
#endif
} // namespace WTF
using WTF::ThreadIdentifier;
using WTF::currentThread;
#endif // Threading_h