Source/WebCore/platform/graphics/cocoa/FontDescriptionCocoa.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. ``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 "FontCascadeDescription.h"

#include "SystemFontDatabaseCoreText.h"
#include <mutex>

namespace WebCore {

template<typename T, typename U, std::size_t size, std::size_t... indices> std::array<T, size> convertArray(U (&array)[size], std::index_sequence<indices...>)
{
    return { { array[indices]... } };
}

template<typename T, typename U, std::size_t size> inline std::array<T, size> convertArray(U (&array)[size])
{
    return convertArray<T>(array, std::make_index_sequence<size> { });
}

static inline std::optional<SystemFontKind> matchSystemFontUse(const AtomString& string)
{
    if (equalLettersIgnoringASCIICase(string, "-webkit-system-font")
        || equalLettersIgnoringASCIICase(string, "-apple-system")
        || equalLettersIgnoringASCIICase(string, "-apple-system-font")
        || equalLettersIgnoringASCIICase(string, "system-ui")
        || equalLettersIgnoringASCIICase(string, "ui-sans-serif"))
        return SystemFontKind::SystemUI;

#if HAVE(DESIGN_SYSTEM_UI_FONTS)
    if (equalLettersIgnoringASCIICase(string, "ui-serif"))
        return SystemFontKind::UISerif;
    if (equalLettersIgnoringASCIICase(string, "ui-monospace"))
        return SystemFontKind::UIMonospace;
    if (equalLettersIgnoringASCIICase(string, "ui-rounded"))
        return SystemFontKind::UIRounded;
#endif

    static const CFStringRef styles[] = {
        kCTUIFontTextStyleHeadline,
        kCTUIFontTextStyleBody,
        kCTUIFontTextStyleTitle1,
        kCTUIFontTextStyleTitle2,
        kCTUIFontTextStyleTitle3,
        kCTUIFontTextStyleSubhead,
        kCTUIFontTextStyleFootnote,
        kCTUIFontTextStyleCaption1,
        kCTUIFontTextStyleCaption2,
        kCTUIFontTextStyleShortHeadline,
        kCTUIFontTextStyleShortBody,
        kCTUIFontTextStyleShortSubhead,
        kCTUIFontTextStyleShortFootnote,
        kCTUIFontTextStyleShortCaption1,
        kCTUIFontTextStyleTallBody,
        kCTUIFontTextStyleTitle0,
        kCTUIFontTextStyleTitle4,
    };

    auto compareAsPointer = [](const AtomString& lhs, const AtomString& rhs) {
        return lhs.impl() < rhs.impl();
    };
    static auto strings = makeNeverDestroyed([&compareAsPointer] {
        auto result = convertArray<AtomString>(styles);
        std::sort(result.begin(), result.end(), compareAsPointer);
        return result;
    }());
    if (std::binary_search(strings.get().begin(), strings.get().end(), string, compareAsPointer))
        return SystemFontKind::TextStyle;

    return std::nullopt;
}

static inline Vector<RetainPtr<CTFontDescriptorRef>> systemFontCascadeList(const FontDescription& description, const AtomString& cssFamily, SystemFontKind systemFontKind, AllowUserInstalledFonts allowUserInstalledFonts)
{
    return SystemFontDatabaseCoreText::singleton().cascadeList(description, cssFamily, systemFontKind, allowUserInstalledFonts);
}

unsigned FontCascadeDescription::effectiveFamilyCount() const
{
    // FIXME: Move all the other system font keywords from fontWithFamilySpecialCase() to here.
    unsigned result = 0;
    for (unsigned i = 0; i < familyCount(); ++i) {
        const auto& cssFamily = familyAt(i);
        if (auto use = matchSystemFontUse(cssFamily))
            result += systemFontCascadeList(*this, cssFamily, *use, shouldAllowUserInstalledFonts()).size();
        else
            ++result;
    }
    return result;
}

FontFamilySpecification FontCascadeDescription::effectiveFamilyAt(unsigned index) const
{
    // The special cases in this function need to match the behavior in FontCacheCoreText.cpp. This code
    // is used for regular (element style) lookups, and the code in FontDescriptionCocoa.cpp is used when
    // src:local(special-cased-name) is specified inside an @font-face block.
    // FIXME: Currently, an @font-face block corresponds to a single item in the font-family: fallback list, which
    // means that "src:local(system-ui)" can't follow the Core Text cascade list (the way it does for regular lookups).
    // These two behaviors should be unified, which would hopefully allow us to delete this duplicate code.
    for (unsigned i = 0; i < familyCount(); ++i) {
        const auto& cssFamily = familyAt(i);
        if (auto use = matchSystemFontUse(cssFamily)) {
            auto cascadeList = systemFontCascadeList(*this, cssFamily, *use, shouldAllowUserInstalledFonts());
            if (index < cascadeList.size())
                return FontFamilySpecification(cascadeList[index].get());
            index -= cascadeList.size();
        }
        else if (!index)
            return cssFamily;
        else
            --index;
    }
    ASSERT_NOT_REACHED();
    return nullAtom();
}

AtomString FontDescription::platformResolveGenericFamily(UScriptCode script, const AtomString& locale, const AtomString& familyName)
{
    ASSERT((locale.isNull() && script == USCRIPT_COMMON) || !locale.isNull());
    if (script == USCRIPT_COMMON)
        return nullAtom();

    // FIXME: Use the system font database to handle standardFamily
    if (familyName == serifFamily)
        return SystemFontDatabaseCoreText::singleton().serifFamily(locale.string());
    if (familyName == sansSerifFamily)
        return SystemFontDatabaseCoreText::singleton().sansSerifFamily(locale.string());
    if (familyName == cursiveFamily)
        return SystemFontDatabaseCoreText::singleton().cursiveFamily(locale.string());
    if (familyName == fantasyFamily)
        return SystemFontDatabaseCoreText::singleton().fantasyFamily(locale.string());
    if (familyName == monospaceFamily)
        return SystemFontDatabaseCoreText::singleton().monospaceFamily(locale.string());

    return nullAtom();
}

}