Source/WebCore/css/typedom/numeric/CSSMathSum.cpp

/*
 * Copyright (C) 2021 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
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#include "config.h"
#include "CSSMathSum.h"

#if ENABLE(CSS_TYPED_OM)

#include "CSSMathNegate.h"
#include "CSSNumericArray.h"
#include "ExceptionOr.h"
#include <wtf/Algorithms.h>
#include <wtf/IsoMallocInlines.h>

namespace WebCore {

WTF_MAKE_ISO_ALLOCATED_IMPL(CSSMathSum);

ExceptionOr<Ref<CSSMathSum>> CSSMathSum::create(FixedVector<CSSNumberish> numberishes)
{
    return create(WTF::map(WTFMove(numberishes), rectifyNumberish));
}

ExceptionOr<Ref<CSSMathSum>> CSSMathSum::create(Vector<Ref<CSSNumericValue>> values)
{
    if (values.isEmpty())
        return Exception { SyntaxError };

    auto type = CSSNumericType::addTypes(values);
    if (!type)
        return Exception { TypeError };

    return adoptRef(*new CSSMathSum(WTFMove(values), WTFMove(*type)));
}

CSSMathSum::CSSMathSum(Vector<Ref<CSSNumericValue>> values, CSSNumericType type)
    : CSSMathValue(WTFMove(type))
    , m_values(CSSNumericArray::create(WTFMove(values)))
{
}

void CSSMathSum::serialize(StringBuilder& builder, OptionSet<SerializationArguments> arguments) const
{
    // https://drafts.css-houdini.org/css-typed-om/#calc-serialization
    if (!arguments.contains(SerializationArguments::WithoutParentheses))
        builder.append(arguments.contains(SerializationArguments::Nested) ? "(" : "calc(");
    m_values->forEach([&](auto& numericValue, bool first) {
        OptionSet<SerializationArguments> operandSerializationArguments { SerializationArguments::Nested };
        operandSerializationArguments.set(SerializationArguments::WithoutParentheses, arguments.contains(SerializationArguments::WithoutParentheses));
        if (!first) {
            if (auto* mathNegate = dynamicDowncast<CSSMathNegate>(numericValue)) {
                builder.append(" - ");
                mathNegate->value().serialize(builder, operandSerializationArguments);
                return;
            }
            builder.append(" + ");
        }
        numericValue.serialize(builder, operandSerializationArguments);
    });
    if (!arguments.contains(SerializationArguments::WithoutParentheses))
        builder.append(')');
}

auto CSSMathSum::toSumValue() const -> std::optional<SumValue>
{
    auto convertToNumericType = [] (const UnitMap& units) -> std::optional<CSSNumericType> {
        // https://drafts.css-houdini.org/css-typed-om/#create-a-type-from-a-unit-map
        CSSNumericType type;
        for (auto& pair : units) {
            auto unit = CSSNumericType::create(pair.key, pair.value);
            if (!unit)
                return std::nullopt;
            auto multipliedType = CSSNumericType::multiplyTypes(type, *unit);
            if (!multipliedType)
                return std::nullopt;
            type = WTFMove(*multipliedType);
        }
        return type;
    };

    // https://drafts.css-houdini.org/css-typed-om/#create-a-sum-value
    SumValue values;
    for (auto& item : m_values->array()) {
        auto value = item->toSumValue();
        if (!value)
            return std::nullopt;
        for (auto& subvalue : *value) {
            auto index = values.findIf([&](auto& value) {
                return value.units == subvalue.units;
            });
            if (index == notFound)
                values.append(WTFMove(subvalue));
            else
                values[index].value += subvalue.value;
        }
    }

    auto type = convertToNumericType(values[0].units);
    if (!type)
        return std::nullopt;
    for (size_t i = 1; i < values.size(); ++i) {
        auto thisType = convertToNumericType(values[i].units);
        if (!thisType)
            return std::nullopt;
        type = CSSNumericType::addTypes(*type, *thisType);
        if (!type)
            return std::nullopt;
    }
    
    return { WTFMove(values) };
}

} // namespace WebCore

#endif