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/*
* Copyright (C) 2014 Apple 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:
* 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.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. 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 INC. 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.
*/
#include "config.h"
#include "RefCounter.h"
namespace WTF {
void RefCounter::Count::ref()
{
bool valueWasZero = !m_value;
++m_value;
if (valueWasZero && m_refCounter)
m_refCounter->m_valueDidChange(true);
}
void RefCounter::Count::deref()
{
ASSERT(m_value);
--m_value;
if (m_value)
return;
// The Count object is kept alive so long as either the RefCounter that created it remains
// allocated, or so long as its reference count is non-zero.
// If the RefCounter has already been deallocted then delete the Count when its reference
// count reaches zero.
if (m_refCounter)
m_refCounter->m_valueDidChange(false);
else
delete this;
}
RefCounter::RefCounter(std::function<void(bool)> valueDidChange)
: m_valueDidChange(valueDidChange)
, m_count(new Count(*this))
{
}
RefCounter::~RefCounter()
{
// The Count object is kept alive so long as either the RefCounter that created it remains
// allocated, or so long as its reference count is non-zero.
// If the reference count of the Count is already zero then delete it now, otherwise
// clear its m_refCounter pointer.
if (m_count->m_value)
m_count->m_refCounter = nullptr;
else
delete m_count;
}
} // namespace WebCore
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