Source/WebCore/style/RenderTreePosition.cpp

/*
 * Copyright (C) 2015 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 "RenderTreePosition.h"

#include "NodeRenderingTraversal.h"
#include "PseudoElement.h"
#include "RenderObject.h"
#include "ShadowRoot.h"

namespace WebCore {

void RenderTreePosition::computeNextSibling(const Node& node)
{
    ASSERT(!node.renderer());
    if (m_hasValidNextSibling) {
        // Stop validating at some point so the assert doesn't make us O(N^2) on debug builds.
        ASSERT(m_parent.isRenderView() || ++m_assertionLimitCounter > 20 || nextSiblingRenderer(node, m_parent) == m_nextSibling);
        return;
    }
    m_nextSibling = nextSiblingRenderer(node, m_parent);
    m_hasValidNextSibling = true;
}

void RenderTreePosition::invalidateNextSibling(const RenderObject& siblingRenderer)
{
    if (!m_hasValidNextSibling)
        return;
    if (m_nextSibling == &siblingRenderer)
        m_hasValidNextSibling = false;
}

RenderObject* RenderTreePosition::previousSiblingRenderer(const Text& textNode)
{
    if (textNode.renderer())
        return textNode.renderer()->previousSibling();
    for (Node* sibling = NodeRenderingTraversal::previousSibling(&textNode); sibling; sibling = NodeRenderingTraversal::previousSibling(sibling)) {
        RenderObject* renderer = sibling->renderer();
        if (renderer && !RenderTreePosition::isRendererReparented(*renderer))
            return renderer;
    }
    if (PseudoElement* before = textNode.parentElement()->beforePseudoElement())
        return before->renderer();
    return nullptr;
}

RenderObject* RenderTreePosition::nextSiblingRenderer(const Node& node, const RenderElement& parentRenderer)
{
    if (!parentRenderer.element())
        return nullptr;
    if (node.isAfterPseudoElement())
        return nullptr;
    Node* sibling = node.isBeforePseudoElement() ? NodeRenderingTraversal::firstChild(parentRenderer.element()) : NodeRenderingTraversal::nextSibling(&node);
    for (; sibling; sibling = NodeRenderingTraversal::nextSibling(sibling)) {
        RenderObject* renderer = sibling->renderer();
        if (renderer && !isRendererReparented(*renderer))
            return renderer;
    }
    if (PseudoElement* after = parentRenderer.element()->afterPseudoElement())
        return after->renderer();
    return nullptr;
}

bool RenderTreePosition::isRendererReparented(const RenderObject& renderer)
{
    if (!renderer.node()->isElementNode())
        return false;
    if (renderer.style().hasFlowInto())
        return true;
    return false;
}

}