LayoutState.cpp   [plain text]

/*
 * Copyright (C) 2018 Apple Inc. All rights reserved.
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 *
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 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
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#include "config.h"
#include "LayoutState.h"

#if ENABLE(LAYOUT_FORMATTING_CONTEXT)

#include "DisplayBox.h"
#include "LayoutBox.h"
#include "LayoutContainer.h"
#include "RuntimeEnabledFeatures.h"
#include <wtf/IsoMallocInlines.h>

namespace WebCore {
namespace Layout {

WTF_MAKE_ISO_ALLOCATED_IMPL(LayoutState);

LayoutState::LayoutState(const LayoutTreeContent& layoutTreeContent)
    : m_layoutTreeContent(makeWeakPtr(layoutTreeContent))
{
    // It makes absolutely no sense to construct a dedicated layout state for a non-formatting context root (layout would be a no-op).
    ASSERT(m_layoutTreeContent->rootLayoutBox().establishesFormattingContext());

    auto quirksMode = [&] {
        auto& document = m_layoutTreeContent->rootRenderer().document();
        if (document.inLimitedQuirksMode())
            return LayoutState::QuirksMode::Limited;
        if (document.inQuirksMode())
            return LayoutState::QuirksMode::Yes;
        return LayoutState::QuirksMode::No;
    };
    setQuirksMode(quirksMode());
}

LayoutState::~LayoutState() = default;

Display::Box& LayoutState::displayBoxForRootLayoutBox()
{
    return displayBoxForLayoutBox(m_layoutTreeContent->rootLayoutBox());
}

Display::Box& LayoutState::displayBoxForLayoutBox(const Box& layoutBox)
{
    return *m_layoutToDisplayBox.ensure(&layoutBox, [] {
        return makeUnique<Display::Box>();
    }).iterator->value;
}

const Display::Box& LayoutState::displayBoxForLayoutBox(const Box& layoutBox) const
{
    ASSERT(hasDisplayBox(layoutBox));
    return *m_layoutToDisplayBox.get(&layoutBox);
}

FormattingState& LayoutState::formattingStateForBox(const Box& layoutBox) const
{
    auto& root = layoutBox.formattingContextRoot();
    RELEASE_ASSERT(m_formattingStates.contains(&root));
    return *m_formattingStates.get(&root);
}

FormattingState& LayoutState::establishedFormattingState(const Container& formattingRoot) const
{
    ASSERT(formattingRoot.establishesFormattingContext());
    RELEASE_ASSERT(m_formattingStates.contains(&formattingRoot));
    return *m_formattingStates.get(&formattingRoot);
}

FormattingState& LayoutState::createFormattingStateForFormattingRootIfNeeded(const Container& formattingContextRoot)
{
    ASSERT(formattingContextRoot.establishesFormattingContext());

    if (formattingContextRoot.establishesInlineFormattingContext()) {
        return *m_formattingStates.ensure(&formattingContextRoot, [&] {

            // If the block container box that initiates this inline formatting context also establishes a block context, the floats outside of the formatting root
            // should not interfere with the content inside.
            // <div style="float: left"></div><div style="overflow: hidden"> <- is a non-intrusive float, because overflow: hidden triggers new block formatting context.</div>
            if (formattingContextRoot.establishesBlockFormattingContext())
                return makeUnique<InlineFormattingState>(FloatingState::create(*this, formattingContextRoot), *this);

            // Otherwise, the formatting context inherits the floats from the parent formatting context.
            // Find the formatting state in which this formatting root lives, not the one it creates and use its floating state.
            auto& parentFormattingState = createFormattingStateForFormattingRootIfNeeded(formattingContextRoot.formattingContextRoot()); 
            auto& parentFloatingState = parentFormattingState.floatingState();
            return makeUnique<InlineFormattingState>(parentFloatingState, *this);
        }).iterator->value;
    }

    if (formattingContextRoot.establishesBlockFormattingContext()) {
        return *m_formattingStates.ensure(&formattingContextRoot, [&] {

            // Block formatting context always establishes a new floating state.
            return makeUnique<BlockFormattingState>(FloatingState::create(*this, formattingContextRoot), *this);
        }).iterator->value;
    }

    if (formattingContextRoot.establishesTableFormattingContext()) {
        return *m_formattingStates.ensure(&formattingContextRoot, [&] {

            // Table formatting context always establishes a new floating state -and it stays empty.
            return makeUnique<TableFormattingState>(FloatingState::create(*this, formattingContextRoot), *this);
        }).iterator->value;
    }

    CRASH();
}

void LayoutState::setViewportSize(const LayoutSize& viewportSize)
{
    if (RuntimeEnabledFeatures::sharedFeatures().layoutFormattingContextIntegrationEnabled()) {
        m_viewportSize = viewportSize;
        return;
    }
    ASSERT_NOT_REACHED();
}

LayoutSize LayoutState::viewportSize() const
{
    if (RuntimeEnabledFeatures::sharedFeatures().layoutFormattingContextIntegrationEnabled())
        return m_viewportSize;
    ASSERT_NOT_REACHED();
    return { };
}

bool LayoutState::isIntegratedRootBoxFirstChild() const
{
    if (RuntimeEnabledFeatures::sharedFeatures().layoutFormattingContextIntegrationEnabled()) {
        auto& rootRenderer = m_layoutTreeContent->rootRenderer();
        ASSERT(rootRenderer.parent());
        return rootRenderer.parent()->firstChild() == &rootRenderer;
    }
    ASSERT_NOT_REACHED();
    return false;
}

}
}

#endif