1/*
2 * Copyright (C) 2012 Apple Computer, Inc.  All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#include "config.h"
27#include "core/editing/SimplifyMarkupCommand.h"
28
29#include "core/dom/NodeRenderStyle.h"
30#include "core/dom/NodeTraversal.h"
31#include "core/rendering/RenderInline.h"
32#include "core/rendering/RenderObject.h"
33#include "core/rendering/style/RenderStyle.h"
34
35namespace blink {
36
37SimplifyMarkupCommand::SimplifyMarkupCommand(Document& document, Node* firstNode, Node* nodeAfterLast)
38    : CompositeEditCommand(document), m_firstNode(firstNode), m_nodeAfterLast(nodeAfterLast)
39{
40}
41
42void SimplifyMarkupCommand::doApply()
43{
44    ContainerNode* rootNode = m_firstNode->parentNode();
45    WillBeHeapVector<RefPtrWillBeMember<ContainerNode> > nodesToRemove;
46
47    // Walk through the inserted nodes, to see if there are elements that could be removed
48    // without affecting the style. The goal is to produce leaner markup even when starting
49    // from a verbose fragment.
50    // We look at inline elements as well as non top level divs that don't have attributes.
51    for (Node* node = m_firstNode.get(); node && node != m_nodeAfterLast; node = NodeTraversal::next(*node)) {
52        if (node->hasChildren() || (node->isTextNode() && node->nextSibling()))
53            continue;
54
55        ContainerNode* startingNode = node->parentNode();
56        if (!startingNode)
57            continue;
58        RenderStyle* startingStyle = startingNode->renderStyle();
59        if (!startingStyle)
60            continue;
61        ContainerNode* currentNode = startingNode;
62        ContainerNode* topNodeWithStartingStyle = 0;
63        while (currentNode != rootNode) {
64            if (currentNode->parentNode() != rootNode && isRemovableBlock(currentNode))
65                nodesToRemove.append(currentNode);
66
67            currentNode = currentNode->parentNode();
68            if (!currentNode)
69                break;
70
71            if (!currentNode->renderer() || !currentNode->renderer()->isRenderInline() || toRenderInline(currentNode->renderer())->alwaysCreateLineBoxes())
72                continue;
73
74            if (currentNode->firstChild() != currentNode->lastChild()) {
75                topNodeWithStartingStyle = 0;
76                break;
77            }
78
79            if (!currentNode->renderStyle()->visualInvalidationDiff(*startingStyle).hasDifference())
80                topNodeWithStartingStyle = currentNode;
81
82        }
83        if (topNodeWithStartingStyle) {
84            for (ContainerNode* node = startingNode; node != topNodeWithStartingStyle; node = node->parentNode())
85                nodesToRemove.append(node);
86        }
87    }
88
89    // we perform all the DOM mutations at once.
90    for (size_t i = 0; i < nodesToRemove.size(); ++i) {
91        // FIXME: We can do better by directly moving children from nodesToRemove[i].
92        int numPrunedAncestors = pruneSubsequentAncestorsToRemove(nodesToRemove, i);
93        if (numPrunedAncestors < 0)
94            continue;
95        removeNodePreservingChildren(nodesToRemove[i], AssumeContentIsAlwaysEditable);
96        i += numPrunedAncestors;
97    }
98}
99
100int SimplifyMarkupCommand::pruneSubsequentAncestorsToRemove(WillBeHeapVector<RefPtrWillBeMember<ContainerNode> >& nodesToRemove, size_t startNodeIndex)
101{
102    size_t pastLastNodeToRemove = startNodeIndex + 1;
103    for (; pastLastNodeToRemove < nodesToRemove.size(); ++pastLastNodeToRemove) {
104        if (nodesToRemove[pastLastNodeToRemove - 1]->parentNode() != nodesToRemove[pastLastNodeToRemove])
105            break;
106        ASSERT(nodesToRemove[pastLastNodeToRemove]->firstChild() == nodesToRemove[pastLastNodeToRemove]->lastChild());
107    }
108
109    ContainerNode* highestAncestorToRemove = nodesToRemove[pastLastNodeToRemove - 1].get();
110    RefPtrWillBeRawPtr<ContainerNode> parent = highestAncestorToRemove->parentNode();
111    if (!parent) // Parent has already been removed.
112        return -1;
113
114    if (pastLastNodeToRemove == startNodeIndex + 1)
115        return 0;
116
117    removeNode(nodesToRemove[startNodeIndex], AssumeContentIsAlwaysEditable);
118    insertNodeBefore(nodesToRemove[startNodeIndex], highestAncestorToRemove, AssumeContentIsAlwaysEditable);
119    removeNode(highestAncestorToRemove, AssumeContentIsAlwaysEditable);
120
121    return pastLastNodeToRemove - startNodeIndex - 1;
122}
123
124void SimplifyMarkupCommand::trace(Visitor* visitor)
125{
126    visitor->trace(m_firstNode);
127    visitor->trace(m_nodeAfterLast);
128    CompositeEditCommand::trace(visitor);
129}
130
131} // namespace blink
132