/*
* Copyright (C) 2011 Google Inc. All rights reserved.
*
* 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
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef ThreadRestrictionVerifier_h
#define ThreadRestrictionVerifier_h
#ifndef NDEBUG
#include "wtf/Assertions.h"
#include "wtf/Threading.h"
namespace WTF {
// Verifies that a class is used in a way that respects its lack of thread-safety.
// The default mode is to verify that the object will only be used on a single thread. The
// thread gets captured when setShared(true) is called.
// The mode may be changed by calling useMutexMode (or turnOffVerification).
class ThreadRestrictionVerifier {
public:
ThreadRestrictionVerifier()
: m_shared(false)
, m_owningThread(0)
{
}
// Indicates that the object may (or may not) be owned by more than one place.
void setShared(bool shared)
{
#if ASSERT_ENABLED
bool previouslyShared = m_shared;
#endif
m_shared = shared;
if (!m_shared)
return;
ASSERT(shared != previouslyShared);
// Capture the current thread to verify that subsequent ref/deref happen on this thread.
m_owningThread = currentThread();
}
// Is it OK to use the object at this moment on the current thread?
bool isSafeToUse() const
{
if (!m_shared)
return true;
return m_owningThread == currentThread();
}
private:
bool m_shared;
// Used by SingleThreadVerificationMode
ThreadIdentifier m_owningThread;
};
}
#endif // !NDEBUG
#endif // ThreadRestrictionVerifier_h