Source/WebCore/platform/WebGLStateTracker.cpp

/*
 * 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. 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 "WebGLStateTracker.h"

#if ENABLE(WEBGL)

namespace WebCore {

WebGLStateTracker::WebGLStateTracker(StateChangeHandler&& handler)
    : m_webGLContextCounter([this](RefCounterEvent) { updateWebGLState(); })
    , m_stateChangeHandler(WTFMove(handler))
{
}

auto WebGLStateTracker::token(GraphicsContext3DPowerPreference powerPreference) -> Token
{
    // We only track high performance WebGL contexts at the moment.
    if (powerPreference != GraphicsContext3DPowerPreference::HighPerformance)
        return { };
    return m_webGLContextCounter.count();
}

void WebGLStateTracker::updateWebGLState()
{
    if (!m_webGLContextCounter.value())
        m_stateChangeHandler(false);
    else if (m_webGLContextCounter.value() == 1)
        m_stateChangeHandler(true);
}

} // namespace WebCore

#endif