Source/core/platform/mac/NSScrollerImpDetails.mm

/*
 * Copyright (C) 2011 Apple Inc. All Rights Reserved.
 * Copyright (C) 2011 Google 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 "RuntimeEnabledFeatures.h"
#include "core/platform/mac/NSScrollerImpDetails.h"

namespace WebCore {

bool isScrollbarOverlayAPIAvailable()
{
    static bool apiAvailable;
    static bool shouldInitialize = true;
    if (shouldInitialize) {
        shouldInitialize = false;
        Class scrollerImpClass = NSClassFromString(@"NSScrollerImp");
        Class scrollerImpPairClass = NSClassFromString(@"NSScrollerImpPair");
        apiAvailable = [scrollerImpClass respondsToSelector:@selector(scrollerImpWithStyle:controlSize:horizontal:replacingScrollerImp:)]
                       && [scrollerImpPairClass instancesRespondToSelector:@selector(scrollerStyle)];
    }
    return apiAvailable;
}

NSScrollerStyle recommendedScrollerStyle() {
    if (RuntimeEnabledFeatures::overlayScrollbarsEnabled())
        return NSScrollerStyleOverlay;
    if ([NSScroller respondsToSelector:@selector(preferredScrollerStyle)])
        return [NSScroller preferredScrollerStyle];
    return NSScrollerStyleLegacy;
}

}