renderobjectchildlist.cpp

linux下开源浏览器WebKit的源码,市面上的很多商用浏览器都是移植自WebKit

/*
 * Copyright (C) 2009 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 COMPUTER, INC. ``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 COMPUTER, INC. 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
 * (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 "RenderObjectChildList.h"

#include "AXObjectCache.h"
#include "RenderBlock.h"
#include "RenderCounter.h"
#include "RenderImageGeneratedContent.h"
#include "RenderInline.h"
#include "RenderLayer.h"
#include "RenderListItem.h"
#include "RenderStyle.h"
#include "RenderTextFragment.h"
#include "RenderView.h"

namespace WebCore {

static void updateListMarkerNumbers(RenderObject* child)
{
    for (RenderObject* r = child; r; r = r->nextSibling()) {
        if (r->isListItem())
            static_cast<RenderListItem*>(r)->updateValue();
    }
}


void RenderObjectChildList::destroyLeftoverChildren()
{
    while (firstChild()) {
        if (firstChild()->isListMarker() || (firstChild()->style()->styleType() == FIRST_LETTER && !firstChild()->isText()))
            firstChild()->remove();  // List markers are owned by their enclosing list and so don't get destroyed by this container. Similarly, first letters are destroyed by their remaining text fragment.
        else {
            // Destroy any anonymous children remaining in the render tree, as well as implicit (shadow) DOM elements like those used in the engine-based text fields.
            if (firstChild()->node())
                firstChild()->node()->setRenderer(0);
            firstChild()->destroy();
        }
    }
}

RenderObject* RenderObjectChildList::removeChildNode(RenderObject* owner, RenderObject* oldChild, bool fullRemove)
{
    ASSERT(oldChild->parent() == owner);

    // So that we'll get the appropriate dirty bit set (either that a normal flow child got yanked or
    // that a positioned child got yanked).  We also repaint, so that the area exposed when the child
    // disappears gets repainted properly.
    if (!owner->documentBeingDestroyed() && fullRemove && oldChild->m_everHadLayout) {
        oldChild->setNeedsLayoutAndPrefWidthsRecalc();
        oldChild->repaint();
    }
        
    // If we have a line box wrapper, delete it.
    if (oldChild->isBox())
        toRenderBox(oldChild)->deleteLineBoxWrapper();

    if (!owner->documentBeingDestroyed() && fullRemove) {
        // if we remove visible child from an invisible parent, we don't know the layer visibility any more
        RenderLayer* layer = 0;
        if (owner->style()->visibility() != VISIBLE && oldChild->style()->visibility() == VISIBLE && !oldChild->hasLayer()) {
            layer = owner->enclosingLayer();
            layer->dirtyVisibleContentStatus();
        }

         // Keep our layer hierarchy updated.
        if (oldChild->firstChild() || oldChild->hasLayer()) {
            if (!layer)
                layer = owner->enclosingLayer();
            oldChild->removeLayers(layer);
        }
        
        // renumber ordered lists
        if (oldChild->isListItem())
            updateListMarkerNumbers(oldChild->nextSibling());
        
        if (oldChild->isPositioned() && owner->childrenInline())
            owner->dirtyLinesFromChangedChild(oldChild);
    }
    
    // If oldChild is the start or end of the selection, then clear the selection to
    // avoid problems of invalid pointers.
    // FIXME: The SelectionController should be responsible for this when it
    // is notified of DOM mutations.
    if (!owner->documentBeingDestroyed() && oldChild->isSelectionBorder())
        owner->view()->clearSelection();

    // remove the child
    if (oldChild->previousSibling())
        oldChild->previousSibling()->setNextSibling(oldChild->nextSibling());
    if (oldChild->nextSibling())
        oldChild->nextSibling()->setPreviousSibling(oldChild->previousSibling());

    if (firstChild() == oldChild)
        setFirstChild(oldChild->nextSibling());
    if (lastChild() == oldChild)
        setLastChild(oldChild->previousSibling());

    oldChild->setPreviousSibling(0);
    oldChild->setNextSibling(0);
    oldChild->setParent(0);

    if (AXObjectCache::accessibilityEnabled())
        owner->document()->axObjectCache()->childrenChanged(owner);

    return oldChild;
}

void RenderObjectChildList::appendChildNode(RenderObject* owner, RenderObject* newChild, bool fullAppend)
{
    ASSERT(newChild->parent() == 0);
    ASSERT(!owner->isBlockFlow() || (!newChild->isTableSection() && !newChild->isTableRow() && !newChild->isTableCell()));

    newChild->setParent(owner);
    RenderObject* lChild = lastChild();

    if (lChild) {
        newChild->setPreviousSibling(lChild);
        lChild->setNextSibling(newChild);
    } else
        setFirstChild(newChild);

    setLastChild(newChild);
    
    if (fullAppend) {
        // Keep our layer hierarchy updated.  Optimize for the common case where we don't have any children
        // and don't have a layer attached to ourselves.
        RenderLayer* layer = 0;
        if (newChild->firstChild() || newChild->hasLayer()) {
            layer = owner->enclosingLayer();
            newChild->addLayers(layer, newChild);
        }

        // if the new child is visible but this object was not, tell the layer it has some visible content
        // that needs to be drawn and layer visibility optimization can't be used
        if (owner->style()->visibility() != VISIBLE && newChild->style()->visibility() == VISIBLE && !newChild->hasLayer()) {
            if (!layer)
                layer = owner->enclosingLayer();
            if (layer)
                layer->setHasVisibleContent(true);
        }
        
        if (!newChild->isFloatingOrPositioned() && owner->childrenInline())
            owner->dirtyLinesFromChangedChild(newChild);
    }

    newChild->setNeedsLayoutAndPrefWidthsRecalc(); // Goes up the containing block hierarchy.
    if (!owner->normalChildNeedsLayout())
        owner->setChildNeedsLayout(true); // We may supply the static position for an absolute positioned child.
    
    if (AXObjectCache::accessibilityEnabled())
        owner->document()->axObjectCache()->childrenChanged(owner);
}

void RenderObjectChildList::insertChildNode(RenderObject* owner, RenderObject* child, RenderObject* beforeChild, bool fullInsert)
{
    if (!beforeChild) {
        appendChildNode(owner, child);
        return;
    }

    ASSERT(!child->parent());
    while (beforeChild->parent() != owner && beforeChild->parent()->isAnonymousBlock())
        beforeChild = beforeChild->parent();
    ASSERT(beforeChild->parent() == owner);

    ASSERT(!owner->isBlockFlow() || (!child->isTableSection() && !child->isTableRow() && !child->isTableCell()));

    if (beforeChild == firstChild())
        setFirstChild(child);

    RenderObject* prev = beforeChild->previousSibling();
    child->setNextSibling(beforeChild);
    beforeChild->setPreviousSibling(child);
    if (prev)
        prev->setNextSibling(child);
    child->setPreviousSibling(prev);

    child->setParent(owner);
    
    if (fullInsert) {
        // Keep our layer hierarchy updated.  Optimize for the common case where we don't have any children
        // and don't have a layer attached to ourselves.
        RenderLayer* layer = 0;
        if (child->firstChild() || child->hasLayer()) {
            layer = owner->enclosingLayer();
            child->addLayers(layer, child);
        }

        // if the new child is visible but this object was not, tell the layer it has some visible content
        // that needs to be drawn and layer visibility optimization can't be used