Source/WTF/wtf/threads/BinarySemaphore.h

/*
 * Copyright (C) 2010-2016 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.
 */

#pragma once

#include <wtf/Condition.h>
#include <wtf/Lock.h>
#include <wtf/Noncopyable.h>
#include <wtf/TimeWithDynamicClockType.h>

namespace WTF {

class BinarySemaphore final {
    WTF_MAKE_NONCOPYABLE(BinarySemaphore);
    WTF_MAKE_FAST_ALLOCATED;
public:
    constexpr BinarySemaphore() = default;

    WTF_EXPORT_PRIVATE void signal();
    WTF_EXPORT_PRIVATE bool waitUntil(const TimeWithDynamicClockType&);

    bool waitFor(Seconds relativeTimeout)
    {
        return waitUntil(MonotonicTime::now() + relativeTimeout);
    }

    void wait()
    {
        waitUntil(ParkingLot::Time::infinity());
    }

private:
    bool m_isSet WTF_GUARDED_BY_LOCK(m_lock) { false };
    Lock m_lock;
    Condition m_condition;
};

} // namespace WTF

using WTF::BinarySemaphore;