blob: 5077a59dc8ebc1d80f6fc67125f51075df6fc2d7 [file] [log] [blame]
/*
* Copyright (C) 2017 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. ``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
* 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 <wtf/ReadWriteLock.h>
#include <wtf/Locker.h>
namespace WTF {
void ReadWriteLock::readLock()
{
auto locker = holdLock(m_lock);
while (m_isWriteLocked || m_numWaitingWriters)
m_cond.wait(m_lock);
m_numReaders++;
}
void ReadWriteLock::readUnlock()
{
auto locker = holdLock(m_lock);
m_numReaders--;
if (!m_numReaders)
m_cond.notifyAll();
}
void ReadWriteLock::writeLock()
{
auto locker = holdLock(m_lock);
while (m_isWriteLocked || m_numReaders) {
m_numWaitingWriters++;
m_cond.wait(m_lock);
m_numWaitingWriters--;
}
m_isWriteLocked = true;
}
void ReadWriteLock::writeUnlock()
{
auto locker = holdLock(m_lock);
m_isWriteLocked = false;
m_cond.notifyAll();
}
} // namespace WTF