root/Source/core/dom/shadow/InsertionPoint.cpp

DEFINITIONS

1. m_registeredWithShadowRoot
2. setDistribution
3. attach
4. detach
5. willRecalcStyle
6. shouldUseFallbackElements
7. canBeActive
8. isActive
9. isShadowInsertionPoint
10. isContentInsertionPoint
11. getDistributedNodes
12. rendererIsNeeded
13. childrenChanged
14. insertedInto
15. removedFrom
16. resolveReprojection
17. collectDestinationInsertionPoints

/*
 * 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.
 *     * 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.
 *     * 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,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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#include "config.h"
#include "core/dom/shadow/InsertionPoint.h"

#include "HTMLNames.h"
#include "core/dom/ElementTraversal.h"
#include "core/dom/QualifiedName.h"
#include "core/dom/StaticNodeList.h"
#include "core/dom/shadow/ElementShadow.h"

namespace WebCore {

using namespace HTMLNames;

InsertionPoint::InsertionPoint(const QualifiedName& tagName, Document& document)
    : HTMLElement(tagName, document, CreateInsertionPoint)
    , m_registeredWithShadowRoot(false)
{
    setHasCustomStyleCallbacks();
}

InsertionPoint::~InsertionPoint()
{
}

void InsertionPoint::setDistribution(ContentDistribution& distribution)
{
    if (shouldUseFallbackElements()) {
        for (Node* child = firstChild(); child; child = child->nextSibling())
            child->lazyReattachIfAttached();
    }

    // Attempt not to reattach nodes that would be distributed to the exact same
    // location by comparing the old and new distributions.

    size_t i = 0;
    size_t j = 0;

    for ( ; i < m_distribution.size() && j < distribution.size(); ++i, ++j) {
        if (m_distribution.size() < distribution.size()) {
            // If the new distribution is larger than the old one, reattach all nodes in
            // the new distribution that were inserted.
            for ( ; j < distribution.size() && m_distribution.at(i) != distribution.at(j); ++j)
                distribution.at(j)->lazyReattachIfAttached();
        } else if (m_distribution.size() > distribution.size()) {
            // If the old distribution is larger than the new one, reattach all nodes in
            // the old distribution that were removed.
            for ( ; i < m_distribution.size() && m_distribution.at(i) != distribution.at(j); ++i)
                m_distribution.at(i)->lazyReattachIfAttached();
        } else if (m_distribution.at(i) != distribution.at(j)) {
            // If both distributions are the same length reattach both old and new.
            m_distribution.at(i)->lazyReattachIfAttached();
            distribution.at(j)->lazyReattachIfAttached();
        }
    }

    // If we hit the end of either list above we need to reattach all remaining nodes.

    for ( ; i < m_distribution.size(); ++i)
        m_distribution.at(i)->lazyReattachIfAttached();

    for ( ; j < distribution.size(); ++j)
        distribution.at(j)->lazyReattachIfAttached();

    m_distribution.swap(distribution);
    m_distribution.shrinkToFit();
}

void InsertionPoint::attach(const AttachContext& context)
{
    // We need to attach the distribution here so that they're inserted in the right order
    // otherwise the n^2 protection inside RenderTreeBuilder will cause them to be
    // inserted in the wrong place later. This also lets distributed nodes benefit from
    // the n^2 protection.
    for (size_t i = 0; i < m_distribution.size(); ++i) {
        if (m_distribution.at(i)->needsAttach())
            m_distribution.at(i)->attach(context);
    }

    HTMLElement::attach(context);
}

void InsertionPoint::detach(const AttachContext& context)
{
    for (size_t i = 0; i < m_distribution.size(); ++i)
        m_distribution.at(i)->lazyReattachIfAttached();

    HTMLElement::detach(context);
}

void InsertionPoint::willRecalcStyle(StyleRecalcChange change)
{
    if (change < Inherit)
        return;
    for (size_t i = 0; i < m_distribution.size(); ++i)
        m_distribution.at(i)->setNeedsStyleRecalc(LocalStyleChange);
}

bool InsertionPoint::shouldUseFallbackElements() const
{
    return isActive() && !hasDistribution();
}

bool InsertionPoint::canBeActive() const
{
    if (!isInShadowTree())
        return false;
    for (Node* node = parentNode(); node; node = node->parentNode()) {
        if (node->isInsertionPoint())
            return false;
    }
    return true;
}

bool InsertionPoint::isActive() const
{
    if (!canBeActive())
        return false;
    ShadowRoot* shadowRoot = containingShadowRoot();
    if (!shadowRoot)
        return false;
    if (!isHTMLShadowElement(*this) || shadowRoot->descendantShadowElementCount() <= 1)
        return true;

    // Slow path only when there are more than one shadow elements in a shadow tree. That should be a rare case.
    const Vector<RefPtr<InsertionPoint> >& insertionPoints = shadowRoot->descendantInsertionPoints();
    for (size_t i = 0; i < insertionPoints.size(); ++i) {
        InsertionPoint* point = insertionPoints[i].get();
        if (isHTMLShadowElement(*point))
            return point == this;
    }
    return true;
}

bool InsertionPoint::isShadowInsertionPoint() const
{
    return isHTMLShadowElement(*this) && isActive();
}

bool InsertionPoint::isContentInsertionPoint() const
{
    return isHTMLContentElement(*this) && isActive();
}

PassRefPtr<NodeList> InsertionPoint::getDistributedNodes()
{
    document().updateDistributionForNodeIfNeeded(this);

    Vector<RefPtr<Node> > nodes;
    nodes.reserveInitialCapacity(m_distribution.size());
    for (size_t i = 0; i < m_distribution.size(); ++i)
        nodes.uncheckedAppend(m_distribution.at(i));

    return StaticNodeList::adopt(nodes);
}

bool InsertionPoint::rendererIsNeeded(const RenderStyle& style)
{
    return !isActive() && HTMLElement::rendererIsNeeded(style);
}

void InsertionPoint::childrenChanged(bool changedByParser, Node* beforeChange, Node* afterChange, int childCountDelta)
{
    HTMLElement::childrenChanged(changedByParser, beforeChange, afterChange, childCountDelta);
    if (ShadowRoot* root = containingShadowRoot()) {
        if (ElementShadow* rootOwner = root->owner())
            rootOwner->setNeedsDistributionRecalc();
    }
}

Node::InsertionNotificationRequest InsertionPoint::insertedInto(ContainerNode* insertionPoint)
{
    HTMLElement::insertedInto(insertionPoint);
    if (ShadowRoot* root = containingShadowRoot()) {
        if (ElementShadow* rootOwner = root->owner()) {
            rootOwner->setNeedsDistributionRecalc();
            if (canBeActive() && !m_registeredWithShadowRoot && insertionPoint->treeScope().rootNode() == root) {
                m_registeredWithShadowRoot = true;
                root->didAddInsertionPoint(this);
                rootOwner->didAffectApplyAuthorStyles();
                if (canAffectSelector())
                    rootOwner->willAffectSelector();
            }
        }
    }

    return InsertionDone;
}

void InsertionPoint::removedFrom(ContainerNode* insertionPoint)
{
    ShadowRoot* root = containingShadowRoot();
    if (!root)
        root = insertionPoint->containingShadowRoot();

    if (root) {
        if (ElementShadow* rootOwner = root->owner())
            rootOwner->setNeedsDistributionRecalc();
    }

    // host can be null when removedFrom() is called from ElementShadow destructor.
    ElementShadow* rootOwner = root ? root->owner() : 0;

    // Since this insertion point is no longer visible from the shadow subtree, it need to clean itself up.
    clearDistribution();

    if (m_registeredWithShadowRoot && insertionPoint->treeScope().rootNode() == root) {
        ASSERT(root);
        m_registeredWithShadowRoot = false;
        root->didRemoveInsertionPoint(this);
        if (rootOwner) {
            rootOwner->didAffectApplyAuthorStyles();
            if (canAffectSelector())
                rootOwner->willAffectSelector();
        }
    }

    HTMLElement::removedFrom(insertionPoint);
}

const InsertionPoint* resolveReprojection(const Node* projectedNode)
{
    ASSERT(projectedNode);
    const InsertionPoint* insertionPoint = 0;
    const Node* current = projectedNode;
    ElementShadow* lastElementShadow = 0;
    while (true) {
        ElementShadow* shadow = shadowWhereNodeCanBeDistributed(*current);
        if (!shadow || shadow == lastElementShadow)
            break;
        lastElementShadow = shadow;
        const InsertionPoint* insertedTo = shadow->finalDestinationInsertionPointFor(projectedNode);
        if (!insertedTo)
            break;
        ASSERT(current != insertedTo);
        current = insertedTo;
        insertionPoint = insertedTo;
    }
    return insertionPoint;
}

void collectDestinationInsertionPoints(const Node& node, Vector<InsertionPoint*, 8>& results)
{
    const Node* current = &node;
    ElementShadow* lastElementShadow = 0;
    while (true) {
        ElementShadow* shadow = shadowWhereNodeCanBeDistributed(*current);
        if (!shadow || shadow == lastElementShadow)
            return;
        lastElementShadow = shadow;
        const DestinationInsertionPoints* insertionPoints = shadow->destinationInsertionPointsFor(&node);
        if (!insertionPoints)
            return;
        for (size_t i = 0; i < insertionPoints->size(); ++i)
            results.append(insertionPoints->at(i).get());
        ASSERT(current != insertionPoints->last().get());
        current = insertionPoints->last().get();
    }
}

} // namespace WebCore