src/third_party/WebKit/Source/core/editing/SimplifyMarkupCommand.cpp

   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
  35 namespace blink {
  36
  37 SimplifyMarkupCommand::SimplifyMarkupCommand(Document& document, Node* firstNode, Node* nodeAfterLast)
  38     : CompositeEditCommand(document), m_firstNode(firstNode), m_nodeAfterLast(nodeAfterLast)
  39 {
  40 }
  41
  42 void 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 = nullptr;
  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
 100 int 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
 124 void SimplifyMarkupCommand::trace(Visitor* visitor)
 125 {
 126     visitor->trace(m_firstNode);
 127     visitor->trace(m_nodeAfterLast);
 128     CompositeEditCommand::trace(visitor);
 129 }
 130
 131 } // namespace blink