Source/WebCore/platform/mac/PublicSuffixMac.mm

/*
 * Copyright (C) 2013 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.
 */

#import "config.h"
#import "PublicSuffix.h"

#if ENABLE(PUBLIC_SUFFIX_LIST)

#import <pal/spi/cf/CFNetworkSPI.h>
#import <wtf/HashMap.h>
#import <wtf/text/StringHash.h>
#import <wtf/URL.h>
#import <wtf/cocoa/NSURLExtras.h>

namespace WebCore {

bool isPublicSuffix(StringView domain)
{
    NSString *host = decodeHostName(domain.createNSString().get());
    return host && _CFHostIsDomainTopLevel((__bridge CFStringRef)host);
}

String topPrivatelyControlledDomain(const String& domain)
{
    if (domain.isEmpty())
        return { };
    if (!domain.isAllASCII())
        return domain;

    static Lock cacheLock;
    Locker locker { cacheLock };

    static NeverDestroyed<HashMap<String, String, ASCIICaseInsensitiveHash>> cache;

    auto isolatedDomain = domain.isolatedCopy();
    
    constexpr auto maximumSizeToPreventUnlimitedGrowth = 128;
    if (cache.get().size() == maximumSizeToPreventUnlimitedGrowth)
        cache.get().remove(cache.get().random());

    return cache.get().ensure(isolatedDomain, [&isolatedDomain] {
        const auto lowercaseDomain = isolatedDomain.convertToASCIILowercase();
        if (lowercaseDomain == "localhost"_s)
            return lowercaseDomain;

        if (URL::hostIsIPAddress(lowercaseDomain))
            return lowercaseDomain;

        size_t separatorPosition;
        for (unsigned labelStart = 0; (separatorPosition = lowercaseDomain.find('.', labelStart)) != notFound; labelStart = separatorPosition + 1) {
            if (isPublicSuffix(StringView(lowercaseDomain).substring(separatorPosition + 1)))
                return lowercaseDomain.substring(labelStart);
        }
        return String();
    }).iterator->value.isolatedCopy();
}

String decodeHostName(const String& domain)
{
    return WTF::decodeHostName(domain);
}

}

#endif