/*
 * Copyright (C) 2018 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

#if PLATFORM(MAC) && __MAC_OS_X_VERSION_MIN_REQUIRED >= 101400

#include <CoreVideo/CVDisplayLink.h>

#include <WebCore/PlatformScreen.h>
#include <wtf/HashSet.h>

namespace WebKit {

class WebPageProxy;
    
class DisplayLink {
public:
    DisplayLink(WebCore::PlatformDisplayID, WebPageProxy&);
    ~DisplayLink();
    
    void addObserver(unsigned observerID);
    void removeObserver(unsigned observerID);
    bool hasObservers() const;

private:
    static CVReturn displayLinkCallback(CVDisplayLinkRef, const CVTimeStamp*, const CVTimeStamp*, CVOptionFlags, CVOptionFlags*, void* data);
    
    CVDisplayLinkRef m_displayLink { nullptr };
    HashSet<unsigned> m_observers;
};

}

#endif