Source/WebCore/layout/integration/LayoutIntegrationBoxTree.cpp

/*
 * Copyright (C) 2020-2022 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
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 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
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 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
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 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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#include "config.h"
#include "LayoutIntegrationBoxTree.h"

#if ENABLE(LAYOUT_FORMATTING_CONTEXT)

#include "InlineWalker.h"
#include "LayoutContainerBox.h"
#include "LayoutInlineTextBox.h"
#include "LayoutLineBreakBox.h"
#include "LayoutReplacedBox.h"
#include "RenderBlockFlow.h"
#include "RenderChildIterator.h"
#include "RenderImage.h"
#include "RenderLineBreak.h"
#include "TextUtil.h"

#if ENABLE(TREE_DEBUGGING)
#include "LayoutIntegrationLineLayout.h"
#endif

namespace WebCore {
namespace LayoutIntegration {

static constexpr size_t smallTreeThreshold = 8;

// FIXME: see webkit.org/b/230964
#define CAN_USE_FIRST_LINE_STYLE_RESOLVE 1

static RenderStyle rootBoxStyle(const RenderStyle& style)
{
    auto clonedStyle = RenderStyle::clone(style);
    clonedStyle.setEffectiveDisplay(DisplayType::Block);
    return clonedStyle;
}

static std::unique_ptr<RenderStyle> rootBoxFirstLineStyle(const RenderBlockFlow& root)
{
#if CAN_USE_FIRST_LINE_STYLE_RESOLVE
    auto& firstLineStyle = root.firstLineStyle();
    if (root.style() == firstLineStyle)
        return { };
    auto clonedStyle = RenderStyle::clonePtr(firstLineStyle);
    clonedStyle->setEffectiveDisplay(DisplayType::Block);
    return clonedStyle;
#else
    UNUSED_PARAM(root);
    return { };
#endif
}

BoxTree::BoxTree(RenderBlockFlow& flow)
    : m_flow(flow)
    , m_root(Layout::Box::ElementAttributes { }, rootBoxStyle(flow.style()), rootBoxFirstLineStyle(flow))
{
    m_root.setIsIntegrationBlockContainer();

    if (flow.isAnonymous())
        m_root.setIsAnonymous();

    buildTree();
}

void BoxTree::buildTree()
{
    auto createChildBox = [&](RenderObject& childRenderer) -> std::unique_ptr<Layout::Box> {
        std::unique_ptr<RenderStyle> firstLineStyle;
#if CAN_USE_FIRST_LINE_STYLE_RESOLVE
        if (&childRenderer.style() != &childRenderer.firstLineStyle())
            firstLineStyle = RenderStyle::clonePtr(childRenderer.firstLineStyle());
#endif
        if (is<RenderText>(childRenderer)) {
            auto& textRenderer = downcast<RenderText>(childRenderer);
            auto style = RenderStyle::createAnonymousStyleWithDisplay(textRenderer.style(), DisplayType::Inline);
            auto text = style.textSecurity() == TextSecurity::None ? textRenderer.text() : RenderBlock::updateSecurityDiscCharacters(style, textRenderer.text());
            auto useSimplifiedTextMeasuring = textRenderer.canUseSimplifiedTextMeasuring() && (!firstLineStyle || firstLineStyle->fontCascade() == style.fontCascade());
            return makeUnique<Layout::InlineTextBox>(text, useSimplifiedTextMeasuring, textRenderer.canUseSimpleFontCodePath(), WTFMove(style), WTFMove(firstLineStyle));
        }

        auto style = RenderStyle::clone(childRenderer.style());
        if (childRenderer.isLineBreak()) {
            auto adjustStyle = [&] (auto& styleToAdjust) {
                styleToAdjust.setDisplay(DisplayType::Inline);
                styleToAdjust.setFloating(Float::None);
                styleToAdjust.setPosition(PositionType::Static);
            };
            adjustStyle(style);
            if (firstLineStyle)
                adjustStyle(*firstLineStyle);

            return makeUnique<Layout::LineBreakBox>(downcast<RenderLineBreak>(childRenderer).isWBR(), WTFMove(style), WTFMove(firstLineStyle));
        }

        if (is<RenderReplaced>(childRenderer))
            return makeUnique<Layout::ReplacedBox>(Layout::Box::ElementAttributes { is<RenderImage>(childRenderer) ? Layout::Box::ElementType::Image : Layout::Box::ElementType::GenericElement }, WTFMove(style), WTFMove(firstLineStyle));

        if (is<RenderBlock>(childRenderer))
            return makeUnique<Layout::ReplacedBox>(Layout::Box::ElementAttributes { Layout::Box::ElementType::GenericElement }, WTFMove(style), WTFMove(firstLineStyle));

        if (is<RenderInline>(childRenderer)) {
            // This looks like continuation renderer.
            auto& renderInline = downcast<RenderInline>(childRenderer);
            auto shouldNotRetainBorderPaddingAndMarginStart = renderInline.isContinuation();
            auto shouldNotRetainBorderPaddingAndMarginEnd = !renderInline.isContinuation() && renderInline.inlineContinuation();
            auto adjustStyleForContinuation = [&] (auto& styleToAdjust) {
                if (shouldNotRetainBorderPaddingAndMarginStart) {
                    styleToAdjust.setMarginStart(RenderStyle::initialMargin());
                    styleToAdjust.resetBorderLeft();
                    styleToAdjust.setPaddingLeft(RenderStyle::initialPadding());
                }
                if (shouldNotRetainBorderPaddingAndMarginEnd) {
                    styleToAdjust.setMarginEnd(RenderStyle::initialMargin());
                    styleToAdjust.resetBorderRight();
                    styleToAdjust.setPaddingRight(RenderStyle::initialPadding());
                }
            };
            adjustStyleForContinuation(style);
            if (firstLineStyle)
                adjustStyleForContinuation(*firstLineStyle);
            return makeUnique<Layout::ContainerBox>(Layout::Box::ElementAttributes { Layout::Box::ElementType::GenericElement }, WTFMove(style), WTFMove(firstLineStyle));
        }

        ASSERT_NOT_REACHED();
        return nullptr;
    };

    for (auto walker = InlineWalker(m_flow); !walker.atEnd(); walker.advance()) {
        auto& childRenderer = *walker.current();
        auto childBox = createChildBox(childRenderer);
        appendChild(makeUniqueRefFromNonNullUniquePtr(WTFMove(childBox)), childRenderer);
    }
}

void BoxTree::appendChild(UniqueRef<Layout::Box> childBox, RenderObject& childRenderer)
{
    auto& parentBox = downcast<Layout::ContainerBox>(layoutBoxForRenderer(*childRenderer.parent()));

    m_boxes.append({ childBox.get(), &childRenderer });

    parentBox.appendChild(WTFMove(childBox));

    if (m_boxes.size() > smallTreeThreshold) {
        if (m_rendererToBoxMap.isEmpty()) {
            for (auto& entry : m_boxes)
                m_rendererToBoxMap.add(entry.renderer, entry.box.get());
        } else
            m_rendererToBoxMap.add(&childRenderer, m_boxes.last().box.get());
    }
}

void BoxTree::updateStyle(const RenderBoxModelObject& renderer)
{
    auto& layoutBox = layoutBoxForRenderer(renderer);
    auto& style = renderer.style();
    auto firstLineStyle = [&] () -> std::unique_ptr<RenderStyle> {
#if CAN_USE_FIRST_LINE_STYLE_RESOLVE
        if (&renderer.style() != &renderer.firstLineStyle())
            return RenderStyle::clonePtr(renderer.firstLineStyle());
        return nullptr;
#else
        return nullptr;
#endif
    };

    if (&layoutBox == &rootLayoutBox())
        layoutBox.updateStyle(rootBoxStyle(style), rootBoxFirstLineStyle(downcast<RenderBlockFlow>(renderer)));
    else
        layoutBox.updateStyle(style, firstLineStyle());

    if (is<Layout::ContainerBox>(layoutBox)) {
        for (auto* child = downcast<Layout::ContainerBox>(layoutBox).firstChild(); child; child = child->nextSibling()) {
            if (child->isInlineTextBox())
                child->updateStyle(RenderStyle::createAnonymousStyleWithDisplay(style, DisplayType::Inline), firstLineStyle());
        }
    }
}

Layout::Box& BoxTree::layoutBoxForRenderer(const RenderObject& renderer)
{
    if (&renderer == &m_flow)
        return m_root;

    if (m_boxes.size() <= smallTreeThreshold) {
        auto index = m_boxes.findIf([&](auto& entry) {
            return entry.renderer == &renderer;
        });
        RELEASE_ASSERT(index != notFound);
        return m_boxes[index].box;
    }

    return *m_rendererToBoxMap.get(&renderer);
}

const Layout::Box& BoxTree::layoutBoxForRenderer(const RenderObject& renderer) const
{
    return const_cast<BoxTree&>(*this).layoutBoxForRenderer(renderer);
}

RenderObject& BoxTree::rendererForLayoutBox(const Layout::Box& box)
{
    if (&box == &m_root)
        return m_flow;

    if (m_boxes.size() <= smallTreeThreshold) {
        auto index = m_boxes.findIf([&](auto& entry) {
            return entry.box.ptr() == &box;
        });
        RELEASE_ASSERT(index != notFound);
        return *m_boxes[index].renderer;
    }

    if (m_boxToRendererMap.isEmpty()) {
        for (auto& entry : m_boxes)
            m_boxToRendererMap.add(entry.box.get(), entry.renderer);
    }
    return *m_boxToRendererMap.get(&box);
}

const RenderObject& BoxTree::rendererForLayoutBox(const Layout::Box& box) const
{
    return const_cast<BoxTree&>(*this).rendererForLayoutBox(box);
}

#if ENABLE(TREE_DEBUGGING)
void showInlineContent(TextStream& stream, const InlineContent& inlineContent, size_t depth)
{
    auto& lines = inlineContent.lines;
    auto& boxes = inlineContent.boxes;

    for (size_t lineIndex = 0; lineIndex < lines.size(); ++lineIndex) {
        auto addSpacing = [&] {
            size_t printedCharacters = 0;
            stream << "-------- --";
            while (++printedCharacters <= depth * 2)
                stream << " ";

        };
        addSpacing();
        auto& line = lines[lineIndex];
        stream << "line at (" << line.lineBoxLeft() << "," << line.lineBoxTop() << ") size (" << line.lineBoxRight() - line.lineBoxLeft() << "x" << line.lineBoxBottom() - line.lineBoxTop() << ") baseline (" << line.baseline() << ") enclosing top (" << line.enclosingContentTop() << ") bottom (" << line.enclosingContentBottom() << ")";
        stream.nextLine();

        addSpacing();
        stream << "  Inline level boxes:";
        stream.nextLine();

        auto outputInlineLevelBox = [&](const auto& inlineLevelBox) {
            addSpacing();
            stream << "    ";
            auto rect = inlineLevelBox.rect();
            auto& layoutBox = inlineLevelBox.layoutBox();
            if (layoutBox.isAtomicInlineLevelBox())
                stream << "Atomic inline level box";
            else if (layoutBox.isLineBreakBox())
                stream << "Line break box";
            else if (layoutBox.isInlineBox())
                stream << "Inline box";
            else
                stream << "Generic inline level box";
            stream
                << " at (" << rect.x() << "," << rect.y() << ")"
                << " size (" << rect.width() << "x" << rect.height() << ")";
            stream.nextLine();
        };
        for (auto& box : boxes) {
            if (box.lineIndex() != lineIndex)
                continue;
            if (!box.layoutBox().isInlineLevelBox())
                continue;
            outputInlineLevelBox(box);
        }

        addSpacing();
        stream << "  Runs:";
        stream.nextLine();
        for (auto& box : boxes) {
            if (box.lineIndex() != lineIndex)
                continue;
            addSpacing();
            stream << "    ";
            if (box.text())
                stream << "text box";
            else
                stream << "box box";
            stream << " at (" << box.left() << "," << box.top() << ") size " << box.width() << "x" << box.height();
            if (box.text())
                stream << " box(" << box.text()->start() << ", " << box.text()->end() << ")";
            stream.nextLine();
        }

    }
}
#endif

}
}

#endif