/*
 * 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. 
 */

#pragma once

#include "BPlatform.h"
#include "StaticMutex.h"
#include <mutex>

#if BOS(DARWIN)
#include <dispatch/dispatch.h>
#endif

namespace bmalloc {

// FIXME: This class should become a common scavenger mechanism for all heaps.
// https://bugs.webkit.org/show_bug.cgi?id=174973

class Scavenger {
public:
    Scavenger(std::lock_guard<StaticMutex>&);
    
    ~Scavenger() = delete;
    
    void scavenge();
    
#if BOS(DARWIN)
    void setScavengerThreadQOSClass(qos_class_t overrideClass) { m_requestedScavengerThreadQOSClass = overrideClass; }
    qos_class_t requestedScavengerThreadQOSClass() const { return m_requestedScavengerThreadQOSClass; }
#endif

private:
#if BOS(DARWIN)
    dispatch_source_t m_pressureHandlerDispatchSource;
    qos_class_t m_requestedScavengerThreadQOSClass { QOS_CLASS_USER_INITIATED };
#endif
};

} // namespace bmalloc