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      1 /*
      2  * Copyright (C) 2011 Google 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 are
      6  * met:
      7  *
      8  *     * Redistributions of source code must retain the above copyright
      9  * notice, this list of conditions and the following disclaimer.
     10  *     * Redistributions in binary form must reproduce the above
     11  * copyright notice, this list of conditions and the following disclaimer
     12  * in the documentation and/or other materials provided with the
     13  * distribution.
     14  *     * Neither the name of Google Inc. nor the names of its
     15  * contributors may be used to endorse or promote products derived from
     16  * this software without specific prior written permission.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     29  */
     30 
     31 #include "config.h"
     32 #include "core/dom/ChildListMutationScope.h"
     33 
     34 #include "core/dom/MutationObserverInterestGroup.h"
     35 #include "core/dom/MutationRecord.h"
     36 #include "core/dom/StaticNodeList.h"
     37 #include "wtf/HashMap.h"
     38 #include "wtf/StdLibExtras.h"
     39 
     40 namespace WebCore {
     41 
     42 typedef HashMap<Node*, ChildListMutationAccumulator*> AccumulatorMap;
     43 static AccumulatorMap& accumulatorMap()
     44 {
     45     DEFINE_STATIC_LOCAL(AccumulatorMap, map, ());
     46     return map;
     47 }
     48 
     49 ChildListMutationAccumulator::ChildListMutationAccumulator(PassRefPtr<Node> target, PassOwnPtr<MutationObserverInterestGroup> observers)
     50     : m_target(target)
     51     , m_lastAdded(0)
     52     , m_observers(observers)
     53 {
     54 }
     55 
     56 ChildListMutationAccumulator::~ChildListMutationAccumulator()
     57 {
     58     if (!isEmpty())
     59         enqueueMutationRecord();
     60     accumulatorMap().remove(m_target.get());
     61 }
     62 
     63 PassRefPtr<ChildListMutationAccumulator> ChildListMutationAccumulator::getOrCreate(Node& target)
     64 {
     65     AccumulatorMap::AddResult result = accumulatorMap().add(&target, 0);
     66     RefPtr<ChildListMutationAccumulator> accumulator;
     67     if (!result.isNewEntry)
     68         accumulator = result.iterator->value;
     69     else {
     70         accumulator = adoptRef(new ChildListMutationAccumulator(PassRefPtr<Node>(target), MutationObserverInterestGroup::createForChildListMutation(target)));
     71         result.iterator->value = accumulator.get();
     72     }
     73     return accumulator.release();
     74 }
     75 
     76 inline bool ChildListMutationAccumulator::isAddedNodeInOrder(Node* child)
     77 {
     78     return isEmpty() || (m_lastAdded == child->previousSibling() && m_nextSibling == child->nextSibling());
     79 }
     80 
     81 void ChildListMutationAccumulator::childAdded(PassRefPtr<Node> prpChild)
     82 {
     83     ASSERT(hasObservers());
     84 
     85     RefPtr<Node> child = prpChild;
     86 
     87     if (!isAddedNodeInOrder(child.get()))
     88         enqueueMutationRecord();
     89 
     90     if (isEmpty()) {
     91         m_previousSibling = child->previousSibling();
     92         m_nextSibling = child->nextSibling();
     93     }
     94 
     95     m_lastAdded = child.get();
     96     m_addedNodes.append(child.release());
     97 }
     98 
     99 inline bool ChildListMutationAccumulator::isRemovedNodeInOrder(Node* child)
    100 {
    101     return isEmpty() || m_nextSibling == child;
    102 }
    103 
    104 void ChildListMutationAccumulator::willRemoveChild(PassRefPtr<Node> prpChild)
    105 {
    106     ASSERT(hasObservers());
    107 
    108     RefPtr<Node> child = prpChild;
    109 
    110     if (!m_addedNodes.isEmpty() || !isRemovedNodeInOrder(child.get()))
    111         enqueueMutationRecord();
    112 
    113     if (isEmpty()) {
    114         m_previousSibling = child->previousSibling();
    115         m_nextSibling = child->nextSibling();
    116         m_lastAdded = child->previousSibling();
    117     } else
    118         m_nextSibling = child->nextSibling();
    119 
    120     m_removedNodes.append(child.release());
    121 }
    122 
    123 void ChildListMutationAccumulator::enqueueMutationRecord()
    124 {
    125     ASSERT(hasObservers());
    126     ASSERT(!isEmpty());
    127 
    128     RefPtr<NodeList> addedNodes = StaticNodeList::adopt(m_addedNodes);
    129     RefPtr<NodeList> removedNodes = StaticNodeList::adopt(m_removedNodes);
    130     RefPtr<MutationRecord> record = MutationRecord::createChildList(m_target, addedNodes.release(), removedNodes.release(), m_previousSibling.release(), m_nextSibling.release());
    131     m_observers->enqueueMutationRecord(record.release());
    132     m_lastAdded = 0;
    133     ASSERT(isEmpty());
    134 }
    135 
    136 bool ChildListMutationAccumulator::isEmpty()
    137 {
    138     bool result = m_removedNodes.isEmpty() && m_addedNodes.isEmpty();
    139 #ifndef NDEBUG
    140     if (result) {
    141         ASSERT(!m_previousSibling);
    142         ASSERT(!m_nextSibling);
    143         ASSERT(!m_lastAdded);
    144     }
    145 #endif
    146     return result;
    147 }
    148 
    149 } // namespace WebCore
    150