Source/WebCore/dom/PseudoElement.cpp

/*
 * Copyright (C) 2012 Google 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:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 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 THE COPYRIGHT
 * OWNER 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,
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#include "config.h"
#include "PseudoElement.h"

#include "ContentData.h"
#include "InspectorInstrumentation.h"
#include "RenderElement.h"
#include "RenderImage.h"
#include "RenderQuote.h"
#include "StyleResolver.h"

namespace WebCore {

const QualifiedName& pseudoElementTagName()
{
    static NeverDestroyed<QualifiedName> name(nullAtom, "<pseudo>", nullAtom);
    return name;
}

String PseudoElement::pseudoElementNameForEvents(PseudoId pseudoId)
{
    static NeverDestroyed<const String> after(ASCIILiteral("::after"));
    static NeverDestroyed<const String> before(ASCIILiteral("::before"));
    switch (pseudoId) {
    case AFTER:
        return after;
    case BEFORE:
        return before;
    default:
        return emptyString();
    }
}

PseudoElement::PseudoElement(Element& host, PseudoId pseudoId)
    : Element(pseudoElementTagName(), host.document(), CreatePseudoElement)
    , m_hostElement(&host)
    , m_pseudoId(pseudoId)
{
    ASSERT(pseudoId == BEFORE || pseudoId == AFTER);
    setHasCustomStyleResolveCallbacks();
}

PseudoElement::~PseudoElement()
{
    ASSERT(!m_hostElement);
}

void PseudoElement::clearHostElement()
{
    InspectorInstrumentation::pseudoElementDestroyed(document().page(), *this);

    m_hostElement = nullptr;
}

Optional<ElementStyle> PseudoElement::resolveCustomStyle(const RenderStyle& parentStyle, const RenderStyle*)
{
    auto* style = m_hostElement->renderer()->getCachedPseudoStyle(m_pseudoId, &parentStyle);
    if (!style)
        return Nullopt;
    return ElementStyle(RenderStyle::clonePtr(*style));
}

void PseudoElement::didAttachRenderers()
{
    RenderElement* renderer = this->renderer();
    if (!renderer || renderer->style().hasFlowFrom())
        return;

    const RenderStyle& style = renderer->style();
    ASSERT(style.contentData());

    for (const ContentData* content = style.contentData(); content; content = content->next()) {
        auto child = content->createContentRenderer(document(), style);
        if (renderer->isChildAllowed(*child, style))
            renderer->addChild(child.leakPtr());
    }
}

bool PseudoElement::rendererIsNeeded(const RenderStyle& style)
{
    return pseudoElementRendererIsNeeded(&style);
}

void PseudoElement::didRecalcStyle(Style::Change)
{
    if (!renderer())
        return;

    // The renderers inside pseudo elements are anonymous so they don't get notified of recalcStyle and must have
    // the style propagated downward manually similar to RenderObject::propagateStyleToAnonymousChildren.
    RenderElement& renderer = *this->renderer();
    for (RenderObject* child = renderer.nextInPreOrder(&renderer); child; child = child->nextInPreOrder(&renderer)) {
        // We only manage the style for the generated content which must be images or text.
        if (!is<RenderImage>(*child) && !is<RenderQuote>(*child))
            continue;
        auto createdStyle = RenderStyle::createStyleInheritingFromPseudoStyle(renderer.style());
        downcast<RenderElement>(*child).setStyle(WTFMove(createdStyle));
    }
}

} // namespace