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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/Node.h"
     37 #include "core/dom/StaticNodeList.h"
     38 #include "wtf/HashMap.h"
     39 #include "wtf/OwnPtr.h"
     40 #include "wtf/StdLibExtras.h"
     41 
     42 namespace WebCore {
     43 
     44 typedef HashMap<Node*, ChildListMutationAccumulator*> AccumulatorMap;
     45 static AccumulatorMap& accumulatorMap()
     46 {
     47     DEFINE_STATIC_LOCAL(AccumulatorMap, map, ());
     48     return map;
     49 }
     50 
     51 ChildListMutationAccumulator::ChildListMutationAccumulator(PassRefPtr<Node> target, PassOwnPtr<MutationObserverInterestGroup> observers)
     52     : m_target(target)
     53     , m_lastAdded(0)
     54     , m_observers(observers)
     55 {
     56 }
     57 
     58 ChildListMutationAccumulator::~ChildListMutationAccumulator()
     59 {
     60     if (!isEmpty())
     61         enqueueMutationRecord();
     62     accumulatorMap().remove(m_target.get());
     63 }
     64 
     65 PassRefPtr<ChildListMutationAccumulator> ChildListMutationAccumulator::getOrCreate(Node* target)
     66 {
     67     AccumulatorMap::AddResult result = accumulatorMap().add(target, 0);
     68     RefPtr<ChildListMutationAccumulator> accumulator;
     69     if (!result.isNewEntry)
     70         accumulator = result.iterator->value;
     71     else {
     72         accumulator = adoptRef(new ChildListMutationAccumulator(target, MutationObserverInterestGroup::createForChildListMutation(target)));
     73         result.iterator->value = accumulator.get();
     74     }
     75     return accumulator.release();
     76 }
     77 
     78 inline bool ChildListMutationAccumulator::isAddedNodeInOrder(Node* child)
     79 {
     80     return isEmpty() || (m_lastAdded == child->previousSibling() && m_nextSibling == child->nextSibling());
     81 }
     82 
     83 void ChildListMutationAccumulator::childAdded(PassRefPtr<Node> prpChild)
     84 {
     85     ASSERT(hasObservers());
     86 
     87     RefPtr<Node> child = prpChild;
     88 
     89     if (!isAddedNodeInOrder(child.get()))
     90         enqueueMutationRecord();
     91 
     92     if (isEmpty()) {
     93         m_previousSibling = child->previousSibling();
     94         m_nextSibling = child->nextSibling();
     95     }
     96 
     97     m_lastAdded = child.get();
     98     m_addedNodes.append(child.release());
     99 }
    100 
    101 inline bool ChildListMutationAccumulator::isRemovedNodeInOrder(Node* child)
    102 {
    103     return isEmpty() || m_nextSibling == child;
    104 }
    105 
    106 void ChildListMutationAccumulator::willRemoveChild(PassRefPtr<Node> prpChild)
    107 {
    108     ASSERT(hasObservers());
    109 
    110     RefPtr<Node> child = prpChild;
    111 
    112     if (!m_addedNodes.isEmpty() || !isRemovedNodeInOrder(child.get()))
    113         enqueueMutationRecord();
    114 
    115     if (isEmpty()) {
    116         m_previousSibling = child->previousSibling();
    117         m_nextSibling = child->nextSibling();
    118         m_lastAdded = child->previousSibling();
    119     } else
    120         m_nextSibling = child->nextSibling();
    121 
    122     m_removedNodes.append(child.release());
    123 }
    124 
    125 void ChildListMutationAccumulator::enqueueMutationRecord()
    126 {
    127     ASSERT(hasObservers());
    128     ASSERT(!isEmpty());
    129 
    130     RefPtr<NodeList> addedNodes = StaticNodeList::adopt(m_addedNodes);
    131     RefPtr<NodeList> removedNodes = StaticNodeList::adopt(m_removedNodes);
    132     RefPtr<MutationRecord> record = MutationRecord::createChildList(m_target, addedNodes.release(), removedNodes.release(), m_previousSibling.release(), m_nextSibling.release());
    133     m_observers->enqueueMutationRecord(record.release());
    134     m_lastAdded = 0;
    135     ASSERT(isEmpty());
    136 }
    137 
    138 bool ChildListMutationAccumulator::isEmpty()
    139 {
    140     bool result = m_removedNodes.isEmpty() && m_addedNodes.isEmpty();
    141 #ifndef NDEBUG
    142     if (result) {
    143         ASSERT(!m_previousSibling);
    144         ASSERT(!m_nextSibling);
    145         ASSERT(!m_lastAdded);
    146     }
    147 #endif
    148     return result;
    149 }
    150 
    151 } // namespace WebCore
    152