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      1 /*
      2  * Copyright (C) 2009, 2010 Apple Inc. All rights reserved.
      3  * Copyright (C) Research In Motion Limited 2010. All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  * 1. Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  * 2. Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in the
     12  *    documentation and/or other materials provided with the distribution.
     13  *
     14  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
     15  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     17  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
     18  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     19  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     20  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     21  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
     22  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     24  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     25  */
     26 
     27 #include "config.h"
     28 #include "core/rendering/RenderObjectChildList.h"
     29 
     30 #include "core/accessibility/AXObjectCache.h"
     31 #include "core/rendering/RenderCounter.h"
     32 #include "core/rendering/RenderLayer.h"
     33 #include "core/rendering/RenderObject.h"
     34 #include "core/rendering/RenderView.h"
     35 #include "core/rendering/style/RenderStyle.h"
     36 
     37 namespace blink {
     38 
     39 void RenderObjectChildList::trace(Visitor* visitor)
     40 {
     41     visitor->trace(m_firstChild);
     42     visitor->trace(m_lastChild);
     43 }
     44 
     45 void RenderObjectChildList::destroyLeftoverChildren()
     46 {
     47     while (firstChild()) {
     48         if (firstChild()->isListMarker() || (firstChild()->style()->styleType() == FIRST_LETTER && !firstChild()->isText())) {
     49             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.
     50         } else {
     51             // 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.
     52             if (firstChild()->node())
     53                 firstChild()->node()->setRenderer(0);
     54             firstChild()->destroy();
     55         }
     56     }
     57 }
     58 
     59 RenderObject* RenderObjectChildList::removeChildNode(RenderObject* owner, RenderObject* oldChild, bool notifyRenderer)
     60 {
     61     ASSERT(oldChild->parent() == owner);
     62 
     63     if (oldChild->isFloatingOrOutOfFlowPositioned())
     64         toRenderBox(oldChild)->removeFloatingOrPositionedChildFromBlockLists();
     65 
     66     {
     67         // FIXME: We should not be allowing paint invalidation during layout. crbug.com/336250
     68         AllowPaintInvalidationScope scoper(owner->frameView());
     69 
     70         // So that we'll get the appropriate dirty bit set (either that a normal flow child got yanked or
     71         // that a positioned child got yanked). We also issue paint invalidations, so that the area exposed when the child
     72         // disappears gets paint invalidated properly.
     73         if (!owner->documentBeingDestroyed() && notifyRenderer && oldChild->everHadLayout()) {
     74             oldChild->setNeedsLayoutAndPrefWidthsRecalc();
     75             invalidatePaintOnRemoval(*oldChild);
     76         }
     77     }
     78 
     79     // If we have a line box wrapper, delete it.
     80     if (oldChild->isBox())
     81         toRenderBox(oldChild)->deleteLineBoxWrapper();
     82 
     83     // If oldChild is the start or end of the selection, then clear the selection to
     84     // avoid problems of invalid pointers.
     85     // FIXME: The FrameSelection should be responsible for this when it
     86     // is notified of DOM mutations.
     87     if (!owner->documentBeingDestroyed() && oldChild->isSelectionBorder())
     88         owner->view()->clearSelection();
     89 
     90     if (!owner->documentBeingDestroyed() && notifyRenderer)
     91         oldChild->willBeRemovedFromTree();
     92 
     93     // WARNING: There should be no code running between willBeRemovedFromTree and the actual removal below.
     94     // This is needed to avoid race conditions where willBeRemovedFromTree would dirty the tree's structure
     95     // and the code running here would force an untimely rebuilding, leaving |oldChild| dangling.
     96 
     97     if (oldChild->previousSibling())
     98         oldChild->previousSibling()->setNextSibling(oldChild->nextSibling());
     99     if (oldChild->nextSibling())
    100         oldChild->nextSibling()->setPreviousSibling(oldChild->previousSibling());
    101 
    102     if (firstChild() == oldChild)
    103         setFirstChild(oldChild->nextSibling());
    104     if (lastChild() == oldChild)
    105         setLastChild(oldChild->previousSibling());
    106 
    107     oldChild->setPreviousSibling(0);
    108     oldChild->setNextSibling(0);
    109     oldChild->setParent(0);
    110 
    111     // rendererRemovedFromTree walks the whole subtree. We can improve performance
    112     // by skipping this step when destroying the entire tree.
    113     if (!owner->documentBeingDestroyed())
    114         RenderCounter::rendererRemovedFromTree(oldChild);
    115 
    116     if (AXObjectCache* cache = owner->document().existingAXObjectCache())
    117         cache->childrenChanged(owner);
    118 
    119     return oldChild;
    120 }
    121 
    122 void RenderObjectChildList::insertChildNode(RenderObject* owner, RenderObject* newChild, RenderObject* beforeChild, bool notifyRenderer)
    123 {
    124     ASSERT(!newChild->parent());
    125     ASSERT(!owner->isRenderBlockFlow() || (!newChild->isTableSection() && !newChild->isTableRow() && !newChild->isTableCell()));
    126 
    127     while (beforeChild && beforeChild->parent() && beforeChild->parent() != owner)
    128         beforeChild = beforeChild->parent();
    129 
    130     // This should never happen, but if it does prevent render tree corruption
    131     // where child->parent() ends up being owner but child->nextSibling()->parent()
    132     // is not owner.
    133     if (beforeChild && beforeChild->parent() != owner) {
    134         ASSERT_NOT_REACHED();
    135         return;
    136     }
    137 
    138     newChild->setParent(owner);
    139 
    140     if (firstChild() == beforeChild)
    141         setFirstChild(newChild);
    142 
    143     if (beforeChild) {
    144         RenderObject* previousSibling = beforeChild->previousSibling();
    145         if (previousSibling)
    146             previousSibling->setNextSibling(newChild);
    147         newChild->setPreviousSibling(previousSibling);
    148         newChild->setNextSibling(beforeChild);
    149         beforeChild->setPreviousSibling(newChild);
    150     } else {
    151         if (lastChild())
    152             lastChild()->setNextSibling(newChild);
    153         newChild->setPreviousSibling(lastChild());
    154         setLastChild(newChild);
    155     }
    156 
    157     if (!owner->documentBeingDestroyed() && notifyRenderer)
    158         newChild->insertedIntoTree();
    159 
    160     if (!owner->documentBeingDestroyed()) {
    161         RenderCounter::rendererSubtreeAttached(newChild);
    162     }
    163 
    164     newChild->setNeedsLayoutAndPrefWidthsRecalcAndFullPaintInvalidation();
    165     if (!owner->normalChildNeedsLayout())
    166         owner->setChildNeedsLayout(); // We may supply the static position for an absolute positioned child.
    167 
    168     if (AXObjectCache* cache = owner->document().axObjectCache())
    169         cache->childrenChanged(owner);
    170 }
    171 
    172 void RenderObjectChildList::invalidatePaintOnRemoval(const RenderObject& oldChild)
    173 {
    174     if (!oldChild.isRooted())
    175         return;
    176     if (oldChild.isBody()) {
    177         oldChild.view()->setShouldDoFullPaintInvalidation(true);
    178         return;
    179     }
    180     if (oldChild.isText()) {
    181         oldChild.parent()->setShouldDoFullPaintInvalidation(true);
    182         return;
    183     }
    184     DisableCompositingQueryAsserts disabler;
    185     oldChild.invalidatePaintUsingContainer(oldChild.containerForPaintInvalidation(), oldChild.previousPaintInvalidationRect(), InvalidationRendererRemoval);
    186 }
    187 
    188 } // namespace blink
    189