Source/WebCore/layout/layouttree/LayoutContainerBox.cpp

/*
 * Copyright (C) 2018 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. 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
 * 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 "LayoutContainerBox.h"

#if ENABLE(LAYOUT_FORMATTING_CONTEXT)

#include "RenderStyle.h"
#include <wtf/IsoMallocInlines.h>

namespace WebCore {
namespace Layout {

WTF_MAKE_ISO_ALLOCATED_IMPL(ContainerBox);

ContainerBox::ContainerBox(std::optional<ElementAttributes> attributes, RenderStyle&& style, std::unique_ptr<RenderStyle>&& firstLineStyle, OptionSet<BaseTypeFlag> baseTypeFlags)
    : Box(attributes, WTFMove(style), WTFMove(firstLineStyle), baseTypeFlags | ContainerBoxFlag)
{
}

ContainerBox::~ContainerBox()
{
    destroyChildren();
}

const Box* ContainerBox::firstInFlowChild() const
{
    if (auto* firstChild = this->firstChild()) {
        if (firstChild->isInFlow())
            return firstChild;
        return firstChild->nextInFlowSibling();
    }
    return nullptr;
}

const Box* ContainerBox::firstInFlowOrFloatingChild() const
{
    if (auto* firstChild = this->firstChild()) {
        if (firstChild->isInFlow() || firstChild->isFloatingPositioned())
            return firstChild;
        return firstChild->nextInFlowOrFloatingSibling();
    }
    return nullptr;
}

const Box* ContainerBox::lastInFlowChild() const
{
    if (auto* lastChild = this->lastChild()) {
        if (lastChild->isInFlow())
            return lastChild;
        return lastChild->previousInFlowSibling();
    }
    return nullptr;
}

const Box* ContainerBox::lastInFlowOrFloatingChild() const
{
    if (auto* lastChild = this->lastChild()) {
        if (lastChild->isInFlow() || lastChild->isFloatingPositioned())
            return lastChild;
        return lastChild->previousInFlowOrFloatingSibling();
    }
    return nullptr;
}

void ContainerBox::appendChild(UniqueRef<Box> childRef)
{
    auto childBox = childRef.moveToUniquePtr();

    childBox->setParent(this);

    if (m_lastChild) {
        m_lastChild->setNextSibling(childBox.get());
        childBox->setPreviousSibling(m_lastChild.get());
    } else
        m_firstChild = childBox.get();

    // Ownership has been transferred.
    m_lastChild = childBox.release();
}

void ContainerBox::destroyChildren()
{
    std::unique_ptr<Box> childToDestroy { m_firstChild.get() };
    
    m_firstChild = nullptr;
    m_lastChild = nullptr;

    while (childToDestroy) {
        childToDestroy->setParent(nullptr);

        std::unique_ptr<Box> nextSibling { childToDestroy->nextSibling() };

        if (nextSibling) {
            childToDestroy->setNextSibling(nullptr);
            nextSibling->setPreviousSibling(nullptr);
        }

        childToDestroy = WTFMove(nextSibling);
    }
}

}
}
#endif