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/RenderObject.h"
33#include "core/rendering/RenderView.h"
34#include "core/rendering/style/RenderStyle.h"
35
36namespace WebCore {
37
38void RenderObjectChildList::destroyLeftoverChildren()
39{
40    while (firstChild()) {
41        if (firstChild()->isListMarker() || (firstChild()->style()->styleType() == FIRST_LETTER && !firstChild()->isText())) {
42            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.
43        } else {
44            // 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.
45            if (firstChild()->node())
46                firstChild()->node()->setRenderer(0);
47            firstChild()->destroy();
48        }
49    }
50}
51
52RenderObject* RenderObjectChildList::removeChildNode(RenderObject* owner, RenderObject* oldChild, bool notifyRenderer)
53{
54    ASSERT(oldChild->parent() == owner);
55
56    if (oldChild->isFloatingOrOutOfFlowPositioned())
57        toRenderBox(oldChild)->removeFloatingOrPositionedChildFromBlockLists();
58
59    // So that we'll get the appropriate dirty bit set (either that a normal flow child got yanked or
60    // that a positioned child got yanked). We also repaint, so that the area exposed when the child
61    // disappears gets repainted properly.
62    if (!owner->documentBeingDestroyed() && notifyRenderer && oldChild->everHadLayout()) {
63        oldChild->setNeedsLayoutAndPrefWidthsRecalc();
64        // We only repaint |oldChild| if we have a RenderLayer as its visual overflow may not be tracked by its parent.
65        if (oldChild->isBody())
66            owner->view()->repaint();
67        else
68            oldChild->repaint();
69    }
70
71    // If we have a line box wrapper, delete it.
72    if (oldChild->isBox())
73        toRenderBox(oldChild)->deleteLineBoxWrapper();
74
75    // If oldChild is the start or end of the selection, then clear the selection to
76    // avoid problems of invalid pointers.
77    // FIXME: The FrameSelection should be responsible for this when it
78    // is notified of DOM mutations.
79    if (!owner->documentBeingDestroyed() && oldChild->isSelectionBorder())
80        owner->view()->clearSelection();
81
82    if (!owner->documentBeingDestroyed() && notifyRenderer)
83        oldChild->willBeRemovedFromTree();
84
85    // WARNING: There should be no code running between willBeRemovedFromTree and the actual removal below.
86    // This is needed to avoid race conditions where willBeRemovedFromTree would dirty the tree's structure
87    // and the code running here would force an untimely rebuilding, leaving |oldChild| dangling.
88
89    if (oldChild->previousSibling())
90        oldChild->previousSibling()->setNextSibling(oldChild->nextSibling());
91    if (oldChild->nextSibling())
92        oldChild->nextSibling()->setPreviousSibling(oldChild->previousSibling());
93
94    if (firstChild() == oldChild)
95        setFirstChild(oldChild->nextSibling());
96    if (lastChild() == oldChild)
97        setLastChild(oldChild->previousSibling());
98
99    oldChild->setPreviousSibling(0);
100    oldChild->setNextSibling(0);
101    oldChild->setParent(0);
102
103    // rendererRemovedFromTree walks the whole subtree. We can improve performance
104    // by skipping this step when destroying the entire tree.
105    if (!owner->documentBeingDestroyed())
106        RenderCounter::rendererRemovedFromTree(oldChild);
107
108    if (AXObjectCache* cache = owner->document().existingAXObjectCache())
109        cache->childrenChanged(owner);
110
111    return oldChild;
112}
113
114void RenderObjectChildList::insertChildNode(RenderObject* owner, RenderObject* newChild, RenderObject* beforeChild, bool notifyRenderer)
115{
116    ASSERT(!newChild->parent());
117    ASSERT(!owner->isRenderBlockFlow() || (!newChild->isTableSection() && !newChild->isTableRow() && !newChild->isTableCell()));
118
119    while (beforeChild && beforeChild->parent() && beforeChild->parent() != owner)
120        beforeChild = beforeChild->parent();
121
122    // This should never happen, but if it does prevent render tree corruption
123    // where child->parent() ends up being owner but child->nextSibling()->parent()
124    // is not owner.
125    if (beforeChild && beforeChild->parent() != owner) {
126        ASSERT_NOT_REACHED();
127        return;
128    }
129
130    newChild->setParent(owner);
131
132    if (firstChild() == beforeChild)
133        setFirstChild(newChild);
134
135    if (beforeChild) {
136        RenderObject* previousSibling = beforeChild->previousSibling();
137        if (previousSibling)
138            previousSibling->setNextSibling(newChild);
139        newChild->setPreviousSibling(previousSibling);
140        newChild->setNextSibling(beforeChild);
141        beforeChild->setPreviousSibling(newChild);
142    } else {
143        if (lastChild())
144            lastChild()->setNextSibling(newChild);
145        newChild->setPreviousSibling(lastChild());
146        setLastChild(newChild);
147    }
148
149    if (!owner->documentBeingDestroyed() && notifyRenderer)
150        newChild->insertedIntoTree();
151
152    if (!owner->documentBeingDestroyed()) {
153        RenderCounter::rendererSubtreeAttached(newChild);
154    }
155
156    newChild->setNeedsLayoutAndPrefWidthsRecalc();
157    if (!owner->normalChildNeedsLayout())
158        owner->setChildNeedsLayout(); // We may supply the static position for an absolute positioned child.
159
160    if (AXObjectCache* cache = owner->document().axObjectCache())
161        cache->childrenChanged(owner);
162}
163
164} // namespace WebCore
165