Source/WebCore/rendering/TextAutoSizing.h

/*
 * Copyright (C) 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple Inc. All rights reserved.
 * Copyright (C) 2026 Samuel Weinig <sam@webkit.org>
 *
 * 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
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 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
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 */

#pragma once

#include "StyleComputedStyle.h"
#include <memory>
#include <wtf/HashMap.h>
#include <wtf/TZoneMalloc.h>

namespace WebCore {

class Text;
class TextAutoSizingValue;

// FIXME: We can probably get rid of this class entirely and use std::unique_ptr<Style::ComputedStyle> as key
// as long as we use the right hash traits.
class TextAutoSizingKey {
public:
    TextAutoSizingKey() = default;
    enum DeletedTag { Deleted };
    explicit TextAutoSizingKey(DeletedTag);
    TextAutoSizingKey(const Style::ComputedStyle&, unsigned hash);

    const Style::ComputedStyle* style() const LIFETIME_BOUND { ASSERT(!isDeleted()); return m_style.get(); }
    bool isDeleted() const { return HashTraits<std::unique_ptr<Style::ComputedStyle>>::isDeletedValue(m_style); }
    static constexpr bool safeToCompareToHashTableEmptyOrDeletedValue = true;

    unsigned hash() const { return m_hash; }
    bool operator==(const TextAutoSizingKey&) const;

private:
    std::unique_ptr<Style::ComputedStyle> m_style;
    unsigned m_hash { 0 };
};

struct TextAutoSizingTraits : HashTraits<TextAutoSizingKey> {
    static const bool emptyValueIsZero = true;
    static void constructDeletedValue(TextAutoSizingKey& slot) { new (NotNull, &slot) TextAutoSizingKey(TextAutoSizingKey::Deleted); }
    static bool isDeletedValue(const TextAutoSizingKey& value) { return value.isDeleted(); }
};

class TextAutoSizing {
    WTF_MAKE_TZONE_ALLOCATED(TextAutoSizing);
public:
    TextAutoSizing();
    ~TextAutoSizing();

    void addTextNode(Text&, float size);
    void updateRenderTree();
    void reset();

private:
    HashMap<TextAutoSizingKey, std::unique_ptr<TextAutoSizingValue>, DefaultHash<TextAutoSizingKey>, TextAutoSizingTraits> m_textNodes;
};

} // namespace WebCore