Source/WebCore/css/FontFace.cpp - WebKit - Git at Google

 /*
  * Copyright (C) 2016 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 "FontFace.h"

 #include "CSSComputedStyleDeclaration.h"
 #include "CSSFontFaceSource.h"
 #include "CSSFontFeatureValue.h"
 #include "CSSFontStyleValue.h"
 #include "CSSParser.h"
 #include "CSSPrimitiveValueMappings.h"
 #include "CSSUnicodeRangeValue.h"
 #include "CSSValueList.h"
 #include "CSSValuePool.h"
 #include "Document.h"
 #include "FontVariantBuilder.h"
 #include "JSFontFace.h"
 #include "StyleProperties.h"
 #include <JavaScriptCore/ArrayBuffer.h>
 #include <JavaScriptCore/ArrayBufferView.h>
 #include <JavaScriptCore/JSCInlines.h>
 #include <wtf/text/StringBuilder.h>

 namespace WebCore {

 static bool populateFontFaceWithArrayBuffer(CSSFontFace& fontFace, Ref<JSC::ArrayBufferView>&& arrayBufferView)
 {
     auto source = std::make_unique<CSSFontFaceSource>(fontFace, String(), nullptr, nullptr, WTFMove(arrayBufferView));
     fontFace.adoptSource(WTFMove(source));
     return false;
 }

 ExceptionOr<Ref<FontFace>> FontFace::create(Document& document, const String& family, Source&& source, const Descriptors& descriptors)
 {
     auto result = adoptRef(*new FontFace(document.fontSelector()));

     bool dataRequiresAsynchronousLoading = true;

     auto setFamilyResult = result->setFamily(family);
     if (setFamilyResult.hasException())
         return setFamilyResult.releaseException();

     auto sourceConversionResult = WTF::switchOn(source,
         [&] (String& string) -> ExceptionOr<void> {
             auto value = FontFace::parseString(string, CSSPropertySrc);
             if (!is<CSSValueList>(value))
                 return Exception { SyntaxError };
             CSSFontFace::appendSources(result->backing(), downcast<CSSValueList>(*value), &document, false);
             return { };
         },
         [&] (RefPtr<ArrayBufferView>& arrayBufferView) -> ExceptionOr<void> {
             dataRequiresAsynchronousLoading = populateFontFaceWithArrayBuffer(result->backing(), arrayBufferView.releaseNonNull());
             return { };
         },
         [&] (RefPtr<ArrayBuffer>& arrayBuffer) -> ExceptionOr<void> {
             unsigned byteLength = arrayBuffer->byteLength();
             auto arrayBufferView = JSC::Uint8Array::create(WTFMove(arrayBuffer), 0, byteLength);
             dataRequiresAsynchronousLoading = populateFontFaceWithArrayBuffer(result->backing(), WTFMove(arrayBufferView));
             return { };
         }
     );

     if (sourceConversionResult.hasException())
         return sourceConversionResult.releaseException();

     // These ternaries match the default strings inside the FontFaceDescriptors dictionary inside FontFace.idl.
     auto setStyleResult = result->setStyle(descriptors.style.isEmpty() ? "normal"_s : descriptors.style);
     if (setStyleResult.hasException())
         return setStyleResult.releaseException();
     auto setWeightResult = result->setWeight(descriptors.weight.isEmpty() ? "normal"_s : descriptors.weight);
     if (setWeightResult.hasException())
         return setWeightResult.releaseException();
     auto setStretchResult = result->setStretch(descriptors.stretch.isEmpty() ? "normal"_s : descriptors.stretch);
     if (setStretchResult.hasException())
         return setStretchResult.releaseException();
     auto setUnicodeRangeResult = result->setUnicodeRange(descriptors.unicodeRange.isEmpty() ? "U+0-10FFFF"_s : descriptors.unicodeRange);
     if (setUnicodeRangeResult.hasException())
         return setUnicodeRangeResult.releaseException();
     auto setVariantResult = result->setVariant(descriptors.variant.isEmpty() ? "normal"_s : descriptors.variant);
     if (setVariantResult.hasException())
         return setVariantResult.releaseException();
     auto setFeatureSettingsResult = result->setFeatureSettings(descriptors.featureSettings.isEmpty() ? "normal"_s : descriptors.featureSettings);
     if (setFeatureSettingsResult.hasException())
         return setFeatureSettingsResult.releaseException();
     auto setDisplayResult = result->setDisplay(descriptors.display.isEmpty() ? "auto"_s : descriptors.display);
     if (setDisplayResult.hasException())
         return setDisplayResult.releaseException();

     if (!dataRequiresAsynchronousLoading) {
         result->backing().load();
         auto status = result->backing().status();
         ASSERT_UNUSED(status, status == CSSFontFace::Status::Success || status == CSSFontFace::Status::Failure);
     }

     return result;
 }

 Ref<FontFace> FontFace::create(CSSFontFace& face)
 {
     return adoptRef(*new FontFace(face));
 }

 FontFace::FontFace(CSSFontSelector& fontSelector)
     : m_backing(CSSFontFace::create(&fontSelector, nullptr, this))
     , m_loadedPromise(*this, &FontFace::loadedPromiseResolve)
 {
     m_backing->addClient(*this);
 }

 FontFace::FontFace(CSSFontFace& face)
     : m_backing(face)
     , m_loadedPromise(*this, &FontFace::loadedPromiseResolve)
 {
     m_backing->addClient(*this);
 }

 FontFace::~FontFace()
 {
     m_backing->removeClient(*this);
 }

 RefPtr<CSSValue> FontFace::parseString(const String& string, CSSPropertyID propertyID)
 {
     // FIXME: Should use the Document to get the right parsing mode.
     return CSSParser::parseFontFaceDescriptor(propertyID, string, HTMLStandardMode);
 }

 ExceptionOr<void> FontFace::setFamily(const String& family)
 {
     if (family.isEmpty())
         return Exception { SyntaxError };

     // FIXME: https://bugs.webkit.org/show_bug.cgi?id=196381 Don't use a list here.
     // See consumeFontFamilyDescriptor() in CSSPropertyParser.cpp for why we're using it.
     auto list = CSSValueList::createCommaSeparated();
     list->append(CSSValuePool::singleton().createFontFamilyValue(family));
     bool success = m_backing->setFamilies(list);
     if (!success)
         return Exception { SyntaxError };
     return { };
 }

 ExceptionOr<void> FontFace::setStyle(const String& style)
 {
     if (style.isEmpty())
         return Exception { SyntaxError };

     if (auto value = parseString(style, CSSPropertyFontStyle)) {
         m_backing->setStyle(*value);
         return { };
     }
     return Exception { SyntaxError };
 }

 ExceptionOr<void> FontFace::setWeight(const String& weight)
 {
     if (weight.isEmpty())
         return Exception { SyntaxError };

     if (auto value = parseString(weight, CSSPropertyFontWeight)) {
         m_backing->setWeight(*value);
         return { };
     }
     return Exception { SyntaxError };
 }

 ExceptionOr<void> FontFace::setStretch(const String& stretch)
 {
     if (stretch.isEmpty())
         return Exception { SyntaxError };

     if (auto value = parseString(stretch, CSSPropertyFontStretch)) {
         m_backing->setStretch(*value);
         return { };
     }
     return Exception { SyntaxError };
 }

 ExceptionOr<void> FontFace::setUnicodeRange(const String& unicodeRange)
 {
     if (unicodeRange.isEmpty())
         return Exception { SyntaxError };

     bool success = false;
     if (auto value = parseString(unicodeRange, CSSPropertyUnicodeRange))
         success = m_backing->setUnicodeRange(*value);
     if (!success)
         return Exception { SyntaxError };
     return { };
 }

 ExceptionOr<void> FontFace::setVariant(const String& variant)
 {
     if (variant.isEmpty())
         return Exception { SyntaxError };

     auto style = MutableStyleProperties::create();
     auto result = CSSParser::parseValue(style, CSSPropertyFontVariant, variant, true, HTMLStandardMode);
     if (result == CSSParser::ParseResult::Error)
         return Exception { SyntaxError };

     // FIXME: Would be much better to stage the new settings and set them all at once
     // instead of this dance where we make a backup and revert to it if something fails.
     FontVariantSettings backup = m_backing->variantSettings();

     auto normal = CSSValuePool::singleton().createIdentifierValue(CSSValueNormal);
     bool success = true;

     if (auto value = style->getPropertyCSSValue(CSSPropertyFontVariantLigatures))
         success &= m_backing->setVariantLigatures(*value);
     else
         m_backing->setVariantLigatures(normal);

     if (auto value = style->getPropertyCSSValue(CSSPropertyFontVariantPosition))
         success &= m_backing->setVariantPosition(*value);
     else
         m_backing->setVariantPosition(normal);

     if (auto value = style->getPropertyCSSValue(CSSPropertyFontVariantCaps))
         success &= m_backing->setVariantCaps(*value);
     else
         m_backing->setVariantCaps(normal);

     if (auto value = style->getPropertyCSSValue(CSSPropertyFontVariantNumeric))
         success &= m_backing->setVariantNumeric(*value);
     else
         m_backing->setVariantNumeric(normal);

     if (auto value = style->getPropertyCSSValue(CSSPropertyFontVariantAlternates))
         success &= m_backing->setVariantAlternates(*value);
     else
         m_backing->setVariantAlternates(normal);

     if (auto value = style->getPropertyCSSValue(CSSPropertyFontVariantEastAsian))
         success &= m_backing->setVariantEastAsian(*value);
     else
         m_backing->setVariantEastAsian(normal);

     if (!success) {
         m_backing->setVariantSettings(backup);
         return Exception { SyntaxError };
     }

     return { };
 }

 ExceptionOr<void> FontFace::setFeatureSettings(const String& featureSettings)
 {
     if (featureSettings.isEmpty())
         return Exception { SyntaxError };

     auto value = parseString(featureSettings, CSSPropertyFontFeatureSettings);
     if (!value)
         return Exception { SyntaxError };
     m_backing->setFeatureSettings(*value);
     return { };
 }

 ExceptionOr<void> FontFace::setDisplay(const String& display)
 {
     if (display.isEmpty())
         return Exception { SyntaxError };

     if (auto value = parseString(display, CSSPropertyFontDisplay)) {
         m_backing->setLoadingBehavior(*value);
         return { };
     }

     return Exception { SyntaxError };
 }

 String FontFace::family() const
 {
     m_backing->updateStyleIfNeeded();

     // FIXME: https://bugs.webkit.org/show_bug.cgi?id=196381 This is only here because CSSFontFace erroneously uses a list of values instead of a single value.
     // See consumeFontFamilyDescriptor() in CSSPropertyParser.cpp.
     if (m_backing->families()->length() == 1) {
         if (m_backing->families()->item(0)) {
             auto& item = *m_backing->families()->item(0);
             if (item.isPrimitiveValue()) {
                 auto& primitiveValue = downcast<CSSPrimitiveValue>(item);
                 if (primitiveValue.isFontFamily()) {
                     auto& fontFamily = primitiveValue.fontFamily();
                     return fontFamily.familyName;
                 }
             }
         }
     }
     return m_backing->families()->cssText();
 }

 String FontFace::style() const
 {
     m_backing->updateStyleIfNeeded();
     auto style = m_backing->italic();

     auto minimum = ComputedStyleExtractor::fontStyleFromStyleValue(style.minimum, FontStyleAxis::ital);
     auto maximum = ComputedStyleExtractor::fontStyleFromStyleValue(style.maximum, FontStyleAxis::ital);

     if (minimum.get().equals(maximum.get()))
         return minimum->cssText();

     auto minimumNonKeyword = ComputedStyleExtractor::fontNonKeywordStyleFromStyleValue(style.minimum);
     auto maximumNonKeyword = ComputedStyleExtractor::fontNonKeywordStyleFromStyleValue(style.maximum);

     ASSERT(minimumNonKeyword->fontStyleValue->valueID() == CSSValueOblique);
     ASSERT(maximumNonKeyword->fontStyleValue->valueID() == CSSValueOblique);

     StringBuilder builder;
     builder.append(minimumNonKeyword->fontStyleValue->cssText());
     builder.append(' ');
     if (minimum->obliqueValue.get() == maximum->obliqueValue.get())
         builder.append(minimumNonKeyword->obliqueValue->cssText());
     else {
         builder.append(minimumNonKeyword->obliqueValue->cssText());
         builder.append(' ');
         builder.append(maximumNonKeyword->obliqueValue->cssText());
     }
     return builder.toString();
 }

 String FontFace::weight() const
 {
     m_backing->updateStyleIfNeeded();
     auto weight = m_backing->weight();

     auto minimum = ComputedStyleExtractor::fontWeightFromStyleValue(weight.minimum);
     auto maximum = ComputedStyleExtractor::fontWeightFromStyleValue(weight.maximum);

     if (minimum.get().equals(maximum.get()))
         return minimum->cssText();

     auto minimumNonKeyword = ComputedStyleExtractor::fontNonKeywordWeightFromStyleValue(weight.minimum);
     auto maximumNonKeyword = ComputedStyleExtractor::fontNonKeywordWeightFromStyleValue(weight.maximum);

     StringBuilder builder;
     builder.append(minimumNonKeyword->cssText());
     builder.append(' ');
     builder.append(maximumNonKeyword->cssText());
     return builder.toString();
 }

 String FontFace::stretch() const
 {
     m_backing->updateStyleIfNeeded();
     auto stretch = m_backing->stretch();

     auto minimum = ComputedStyleExtractor::fontStretchFromStyleValue(stretch.minimum);
     auto maximum = ComputedStyleExtractor::fontStretchFromStyleValue(stretch.maximum);

     if (minimum.get().equals(maximum.get()))
         return minimum->cssText();

     auto minimumNonKeyword = ComputedStyleExtractor::fontNonKeywordStretchFromStyleValue(stretch.minimum);
     auto maximumNonKeyword = ComputedStyleExtractor::fontNonKeywordStretchFromStyleValue(stretch.maximum);

     StringBuilder builder;
     builder.append(minimumNonKeyword->cssText());
     builder.append(' ');
     builder.append(maximumNonKeyword->cssText());
     return builder.toString();
 }

 String FontFace::unicodeRange() const
 {
     m_backing->updateStyleIfNeeded();
     if (!m_backing->ranges().size())
         return "U+0-10FFFF"_s;
     auto values = CSSValueList::createCommaSeparated();
     for (auto& range : m_backing->ranges())
         values->append(CSSUnicodeRangeValue::create(range.from, range.to));
     return values->cssText();
 }

 String FontFace::variant() const
 {
     m_backing->updateStyleIfNeeded();
     return computeFontVariant(m_backing->variantSettings())->cssText();
 }

 String FontFace::featureSettings() const
 {
     m_backing->updateStyleIfNeeded();
     if (!m_backing->featureSettings().size())
         return "normal"_s;
     auto list = CSSValueList::createCommaSeparated();
     for (auto& feature : m_backing->featureSettings())
         list->append(CSSFontFeatureValue::create(FontTag(feature.tag()), feature.value()));
     return list->cssText();
 }

 String FontFace::display() const
 {
     m_backing->updateStyleIfNeeded();
     return CSSValuePool::singleton().createValue(m_backing->loadingBehavior())->cssText();
 }

 auto FontFace::status() const -> LoadStatus
 {
     switch (m_backing->status()) {
     case CSSFontFace::Status::Pending:
         return LoadStatus::Unloaded;
     case CSSFontFace::Status::Loading:
         return LoadStatus::Loading;
     case CSSFontFace::Status::TimedOut:
         return LoadStatus::Error;
     case CSSFontFace::Status::Success:
         return LoadStatus::Loaded;
     case CSSFontFace::Status::Failure:
         return LoadStatus::Error;
     }
     ASSERT_NOT_REACHED();
     return LoadStatus::Error;
 }

 void FontFace::adopt(CSSFontFace& newFace)
 {
     m_backing->removeClient(*this);
     m_backing = newFace;
     m_backing->addClient(*this);
     newFace.setWrapper(*this);
 }

 void FontFace::fontStateChanged(CSSFontFace& face, CSSFontFace::Status, CSSFontFace::Status newState)
 {
     ASSERT_UNUSED(face, &face == m_backing.ptr());
     switch (newState) {
     case CSSFontFace::Status::Loading:
         // We still need to resolve promises when loading completes, even if all references to use have fallen out of scope.
         ref();
         break;
     case CSSFontFace::Status::TimedOut:
         break;
     case CSSFontFace::Status::Success:
         // FIXME: This check should not be needed, but because FontFace's are sometimes adopted after they have already
         // gone through a load cycle, we can sometimes come back through here and try to resolve the promise again.
         if (!m_loadedPromise.isFulfilled())
             m_loadedPromise.resolve(*this);
         deref();
         return;
     case CSSFontFace::Status::Failure:
         // FIXME: This check should not be needed, but because FontFace's are sometimes adopted after they have already
         // gone through a load cycle, we can sometimes come back through here and try to resolve the promise again.
         if (!m_loadedPromise.isFulfilled())
             m_loadedPromise.reject(Exception { NetworkError });
         deref();
         return;
     case CSSFontFace::Status::Pending:
         ASSERT_NOT_REACHED();
         return;
     }
 }

 auto FontFace::load() -> LoadedPromise&
 {
     m_backing->load();
     return m_loadedPromise;
 }

 FontFace& FontFace::loadedPromiseResolve()
 {
     return *this;
 }

 }
	/*
	* Copyright (C) 2016 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 "FontFace.h"

	#include "CSSComputedStyleDeclaration.h"
	#include "CSSFontFaceSource.h"
	#include "CSSFontFeatureValue.h"
	#include "CSSFontStyleValue.h"
	#include "CSSParser.h"
	#include "CSSPrimitiveValueMappings.h"
	#include "CSSUnicodeRangeValue.h"
	#include "CSSValueList.h"
	#include "CSSValuePool.h"
	#include "Document.h"
	#include "FontVariantBuilder.h"
	#include "JSFontFace.h"
	#include "StyleProperties.h"
	#include <JavaScriptCore/ArrayBuffer.h>
	#include <JavaScriptCore/ArrayBufferView.h>
	#include <JavaScriptCore/JSCInlines.h>
	#include <wtf/text/StringBuilder.h>

	namespace WebCore {

	static bool populateFontFaceWithArrayBuffer(CSSFontFace& fontFace, Ref<JSC::ArrayBufferView>&& arrayBufferView)
	{
	auto source = std::make_unique<CSSFontFaceSource>(fontFace, String(), nullptr, nullptr, WTFMove(arrayBufferView));
	fontFace.adoptSource(WTFMove(source));
	return false;
	}

	ExceptionOr<Ref<FontFace>> FontFace::create(Document& document, const String& family, Source&& source, const Descriptors& descriptors)
	{
	auto result = adoptRef(*new FontFace(document.fontSelector()));

	bool dataRequiresAsynchronousLoading = true;

	auto setFamilyResult = result->setFamily(family);
	if (setFamilyResult.hasException())
	return setFamilyResult.releaseException();

	auto sourceConversionResult = WTF::switchOn(source,
	[&] (String& string) -> ExceptionOr<void> {
	auto value = FontFace::parseString(string, CSSPropertySrc);
	if (!is<CSSValueList>(value))
	return Exception { SyntaxError };
	CSSFontFace::appendSources(result->backing(), downcast<CSSValueList>(*value), &document, false);
	return { };
	},
	[&] (RefPtr<ArrayBufferView>& arrayBufferView) -> ExceptionOr<void> {
	dataRequiresAsynchronousLoading = populateFontFaceWithArrayBuffer(result->backing(), arrayBufferView.releaseNonNull());
	return { };
	},
	[&] (RefPtr<ArrayBuffer>& arrayBuffer) -> ExceptionOr<void> {
	unsigned byteLength = arrayBuffer->byteLength();
	auto arrayBufferView = JSC::Uint8Array::create(WTFMove(arrayBuffer), 0, byteLength);
	dataRequiresAsynchronousLoading = populateFontFaceWithArrayBuffer(result->backing(), WTFMove(arrayBufferView));
	return { };
	}
	);

	if (sourceConversionResult.hasException())
	return sourceConversionResult.releaseException();

	// These ternaries match the default strings inside the FontFaceDescriptors dictionary inside FontFace.idl.
	auto setStyleResult = result->setStyle(descriptors.style.isEmpty() ? "normal"_s : descriptors.style);
	if (setStyleResult.hasException())
	return setStyleResult.releaseException();
	auto setWeightResult = result->setWeight(descriptors.weight.isEmpty() ? "normal"_s : descriptors.weight);
	if (setWeightResult.hasException())
	return setWeightResult.releaseException();
	auto setStretchResult = result->setStretch(descriptors.stretch.isEmpty() ? "normal"_s : descriptors.stretch);
	if (setStretchResult.hasException())
	return setStretchResult.releaseException();
	auto setUnicodeRangeResult = result->setUnicodeRange(descriptors.unicodeRange.isEmpty() ? "U+0-10FFFF"_s : descriptors.unicodeRange);
	if (setUnicodeRangeResult.hasException())
	return setUnicodeRangeResult.releaseException();
	auto setVariantResult = result->setVariant(descriptors.variant.isEmpty() ? "normal"_s : descriptors.variant);
	if (setVariantResult.hasException())
	return setVariantResult.releaseException();
	auto setFeatureSettingsResult = result->setFeatureSettings(descriptors.featureSettings.isEmpty() ? "normal"_s : descriptors.featureSettings);
	if (setFeatureSettingsResult.hasException())
	return setFeatureSettingsResult.releaseException();
	auto setDisplayResult = result->setDisplay(descriptors.display.isEmpty() ? "auto"_s : descriptors.display);
	if (setDisplayResult.hasException())
	return setDisplayResult.releaseException();

	if (!dataRequiresAsynchronousLoading) {
	result->backing().load();
	auto status = result->backing().status();
	ASSERT_UNUSED(status, status == CSSFontFace::Status::Success \|\| status == CSSFontFace::Status::Failure);
	}

	return result;
	}

	Ref<FontFace> FontFace::create(CSSFontFace& face)
	{
	return adoptRef(*new FontFace(face));
	}

	FontFace::FontFace(CSSFontSelector& fontSelector)
	: m_backing(CSSFontFace::create(&fontSelector, nullptr, this))
	, m_loadedPromise(*this, &FontFace::loadedPromiseResolve)
	{
	m_backing->addClient(*this);
	}

	FontFace::FontFace(CSSFontFace& face)
	: m_backing(face)
	, m_loadedPromise(*this, &FontFace::loadedPromiseResolve)
	{
	m_backing->addClient(*this);
	}

	FontFace::~FontFace()
	{
	m_backing->removeClient(*this);
	}

	RefPtr<CSSValue> FontFace::parseString(const String& string, CSSPropertyID propertyID)
	{
	// FIXME: Should use the Document to get the right parsing mode.
	return CSSParser::parseFontFaceDescriptor(propertyID, string, HTMLStandardMode);
	}

	ExceptionOr<void> FontFace::setFamily(const String& family)
	{
	if (family.isEmpty())
	return Exception { SyntaxError };

	// FIXME: https://bugs.webkit.org/show_bug.cgi?id=196381 Don't use a list here.
	// See consumeFontFamilyDescriptor() in CSSPropertyParser.cpp for why we're using it.
	auto list = CSSValueList::createCommaSeparated();
	list->append(CSSValuePool::singleton().createFontFamilyValue(family));
	bool success = m_backing->setFamilies(list);
	if (!success)
	return Exception { SyntaxError };
	return { };
	}

	ExceptionOr<void> FontFace::setStyle(const String& style)
	{
	if (style.isEmpty())
	return Exception { SyntaxError };

	if (auto value = parseString(style, CSSPropertyFontStyle)) {
	m_backing->setStyle(*value);
	return { };
	}
	return Exception { SyntaxError };
	}

	ExceptionOr<void> FontFace::setWeight(const String& weight)
	{
	if (weight.isEmpty())
	return Exception { SyntaxError };

	if (auto value = parseString(weight, CSSPropertyFontWeight)) {
	m_backing->setWeight(*value);
	return { };
	}
	return Exception { SyntaxError };
	}

	ExceptionOr<void> FontFace::setStretch(const String& stretch)
	{
	if (stretch.isEmpty())
	return Exception { SyntaxError };

	if (auto value = parseString(stretch, CSSPropertyFontStretch)) {
	m_backing->setStretch(*value);
	return { };
	}
	return Exception { SyntaxError };
	}

	ExceptionOr<void> FontFace::setUnicodeRange(const String& unicodeRange)
	{
	if (unicodeRange.isEmpty())
	return Exception { SyntaxError };

	bool success = false;
	if (auto value = parseString(unicodeRange, CSSPropertyUnicodeRange))
	success = m_backing->setUnicodeRange(*value);
	if (!success)
	return Exception { SyntaxError };
	return { };
	}

	ExceptionOr<void> FontFace::setVariant(const String& variant)
	{
	if (variant.isEmpty())
	return Exception { SyntaxError };

	auto style = MutableStyleProperties::create();
	auto result = CSSParser::parseValue(style, CSSPropertyFontVariant, variant, true, HTMLStandardMode);
	if (result == CSSParser::ParseResult::Error)
	return Exception { SyntaxError };

	// FIXME: Would be much better to stage the new settings and set them all at once
	// instead of this dance where we make a backup and revert to it if something fails.
	FontVariantSettings backup = m_backing->variantSettings();

	auto normal = CSSValuePool::singleton().createIdentifierValue(CSSValueNormal);
	bool success = true;

	if (auto value = style->getPropertyCSSValue(CSSPropertyFontVariantLigatures))
	success &= m_backing->setVariantLigatures(*value);
	else
	m_backing->setVariantLigatures(normal);

	if (auto value = style->getPropertyCSSValue(CSSPropertyFontVariantPosition))
	success &= m_backing->setVariantPosition(*value);
	else
	m_backing->setVariantPosition(normal);

	if (auto value = style->getPropertyCSSValue(CSSPropertyFontVariantCaps))
	success &= m_backing->setVariantCaps(*value);
	else
	m_backing->setVariantCaps(normal);

	if (auto value = style->getPropertyCSSValue(CSSPropertyFontVariantNumeric))
	success &= m_backing->setVariantNumeric(*value);
	else
	m_backing->setVariantNumeric(normal);

	if (auto value = style->getPropertyCSSValue(CSSPropertyFontVariantAlternates))
	success &= m_backing->setVariantAlternates(*value);
	else
	m_backing->setVariantAlternates(normal);

	if (auto value = style->getPropertyCSSValue(CSSPropertyFontVariantEastAsian))
	success &= m_backing->setVariantEastAsian(*value);
	else
	m_backing->setVariantEastAsian(normal);

	if (!success) {
	m_backing->setVariantSettings(backup);
	return Exception { SyntaxError };
	}

	return { };
	}

	ExceptionOr<void> FontFace::setFeatureSettings(const String& featureSettings)
	{
	if (featureSettings.isEmpty())
	return Exception { SyntaxError };

	auto value = parseString(featureSettings, CSSPropertyFontFeatureSettings);
	if (!value)
	return Exception { SyntaxError };
	m_backing->setFeatureSettings(*value);
	return { };
	}

	ExceptionOr<void> FontFace::setDisplay(const String& display)
	{
	if (display.isEmpty())
	return Exception { SyntaxError };

	if (auto value = parseString(display, CSSPropertyFontDisplay)) {
	m_backing->setLoadingBehavior(*value);
	return { };
	}

	return Exception { SyntaxError };
	}

	String FontFace::family() const
	{
	m_backing->updateStyleIfNeeded();

	// FIXME: https://bugs.webkit.org/show_bug.cgi?id=196381 This is only here because CSSFontFace erroneously uses a list of values instead of a single value.
	// See consumeFontFamilyDescriptor() in CSSPropertyParser.cpp.
	if (m_backing->families()->length() == 1) {
	if (m_backing->families()->item(0)) {
	auto& item = *m_backing->families()->item(0);
	if (item.isPrimitiveValue()) {
	auto& primitiveValue = downcast<CSSPrimitiveValue>(item);
	if (primitiveValue.isFontFamily()) {
	auto& fontFamily = primitiveValue.fontFamily();
	return fontFamily.familyName;
	}
	}
	}
	}
	return m_backing->families()->cssText();
	}

	String FontFace::style() const
	{
	m_backing->updateStyleIfNeeded();
	auto style = m_backing->italic();

	auto minimum = ComputedStyleExtractor::fontStyleFromStyleValue(style.minimum, FontStyleAxis::ital);
	auto maximum = ComputedStyleExtractor::fontStyleFromStyleValue(style.maximum, FontStyleAxis::ital);

	if (minimum.get().equals(maximum.get()))
	return minimum->cssText();

	auto minimumNonKeyword = ComputedStyleExtractor::fontNonKeywordStyleFromStyleValue(style.minimum);
	auto maximumNonKeyword = ComputedStyleExtractor::fontNonKeywordStyleFromStyleValue(style.maximum);

	ASSERT(minimumNonKeyword->fontStyleValue->valueID() == CSSValueOblique);
	ASSERT(maximumNonKeyword->fontStyleValue->valueID() == CSSValueOblique);

	StringBuilder builder;
	builder.append(minimumNonKeyword->fontStyleValue->cssText());
	builder.append(' ');
	if (minimum->obliqueValue.get() == maximum->obliqueValue.get())
	builder.append(minimumNonKeyword->obliqueValue->cssText());
	else {
	builder.append(minimumNonKeyword->obliqueValue->cssText());
	builder.append(' ');
	builder.append(maximumNonKeyword->obliqueValue->cssText());
	}
	return builder.toString();
	}

	String FontFace::weight() const
	{
	m_backing->updateStyleIfNeeded();
	auto weight = m_backing->weight();

	auto minimum = ComputedStyleExtractor::fontWeightFromStyleValue(weight.minimum);
	auto maximum = ComputedStyleExtractor::fontWeightFromStyleValue(weight.maximum);

	if (minimum.get().equals(maximum.get()))
	return minimum->cssText();

	auto minimumNonKeyword = ComputedStyleExtractor::fontNonKeywordWeightFromStyleValue(weight.minimum);
	auto maximumNonKeyword = ComputedStyleExtractor::fontNonKeywordWeightFromStyleValue(weight.maximum);

	StringBuilder builder;
	builder.append(minimumNonKeyword->cssText());
	builder.append(' ');
	builder.append(maximumNonKeyword->cssText());
	return builder.toString();
	}

	String FontFace::stretch() const
	{
	m_backing->updateStyleIfNeeded();
	auto stretch = m_backing->stretch();

	auto minimum = ComputedStyleExtractor::fontStretchFromStyleValue(stretch.minimum);
	auto maximum = ComputedStyleExtractor::fontStretchFromStyleValue(stretch.maximum);

	if (minimum.get().equals(maximum.get()))
	return minimum->cssText();

	auto minimumNonKeyword = ComputedStyleExtractor::fontNonKeywordStretchFromStyleValue(stretch.minimum);
	auto maximumNonKeyword = ComputedStyleExtractor::fontNonKeywordStretchFromStyleValue(stretch.maximum);

	StringBuilder builder;
	builder.append(minimumNonKeyword->cssText());
	builder.append(' ');
	builder.append(maximumNonKeyword->cssText());
	return builder.toString();
	}

	String FontFace::unicodeRange() const
	{
	m_backing->updateStyleIfNeeded();
	if (!m_backing->ranges().size())
	return "U+0-10FFFF"_s;
	auto values = CSSValueList::createCommaSeparated();
	for (auto& range : m_backing->ranges())
	values->append(CSSUnicodeRangeValue::create(range.from, range.to));
	return values->cssText();
	}

	String FontFace::variant() const
	{
	m_backing->updateStyleIfNeeded();
	return computeFontVariant(m_backing->variantSettings())->cssText();
	}

	String FontFace::featureSettings() const
	{
	m_backing->updateStyleIfNeeded();
	if (!m_backing->featureSettings().size())
	return "normal"_s;
	auto list = CSSValueList::createCommaSeparated();
	for (auto& feature : m_backing->featureSettings())
	list->append(CSSFontFeatureValue::create(FontTag(feature.tag()), feature.value()));
	return list->cssText();
	}

	String FontFace::display() const
	{
	m_backing->updateStyleIfNeeded();
	return CSSValuePool::singleton().createValue(m_backing->loadingBehavior())->cssText();
	}

	auto FontFace::status() const -> LoadStatus
	{
	switch (m_backing->status()) {
	case CSSFontFace::Status::Pending:
	return LoadStatus::Unloaded;
	case CSSFontFace::Status::Loading:
	return LoadStatus::Loading;
	case CSSFontFace::Status::TimedOut:
	return LoadStatus::Error;
	case CSSFontFace::Status::Success:
	return LoadStatus::Loaded;
	case CSSFontFace::Status::Failure:
	return LoadStatus::Error;
	}
	ASSERT_NOT_REACHED();
	return LoadStatus::Error;
	}

	void FontFace::adopt(CSSFontFace& newFace)
	{
	m_backing->removeClient(*this);
	m_backing = newFace;
	m_backing->addClient(*this);
	newFace.setWrapper(*this);
	}

	void FontFace::fontStateChanged(CSSFontFace& face, CSSFontFace::Status, CSSFontFace::Status newState)
	{
	ASSERT_UNUSED(face, &face == m_backing.ptr());
	switch (newState) {
	case CSSFontFace::Status::Loading:
	// We still need to resolve promises when loading completes, even if all references to use have fallen out of scope.
	ref();
	break;
	case CSSFontFace::Status::TimedOut:
	break;
	case CSSFontFace::Status::Success:
	// FIXME: This check should not be needed, but because FontFace's are sometimes adopted after they have already
	// gone through a load cycle, we can sometimes come back through here and try to resolve the promise again.
	if (!m_loadedPromise.isFulfilled())
	m_loadedPromise.resolve(*this);
	deref();
	return;
	case CSSFontFace::Status::Failure:
	// FIXME: This check should not be needed, but because FontFace's are sometimes adopted after they have already
	// gone through a load cycle, we can sometimes come back through here and try to resolve the promise again.
	if (!m_loadedPromise.isFulfilled())
	m_loadedPromise.reject(Exception { NetworkError });
	deref();
	return;
	case CSSFontFace::Status::Pending:
	ASSERT_NOT_REACHED();
	return;
	}
	}

	auto FontFace::load() -> LoadedPromise&
	{
	m_backing->load();
	return m_loadedPromise;
	}

	FontFace& FontFace::loadedPromiseResolve()
	{
	return *this;
	}

	}