src/third_party/WebKit/Source/core/rendering/RenderObjectChildList.cpp

   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,
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  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