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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 #ifndef ChildListMutationScope_h
     32 #define ChildListMutationScope_h
     33 
     34 #include "core/dom/Document.h"
     35 #include "core/dom/MutationObserver.h"
     36 #include "core/dom/Node.h"
     37 #include "wtf/Noncopyable.h"
     38 #include "wtf/OwnPtr.h"
     39 #include "wtf/RefCounted.h"
     40 
     41 namespace WebCore {
     42 
     43 class MutationObserverInterestGroup;
     44 
     45 // ChildListMutationAccumulator is not meant to be used directly; ChildListMutationScope is the public interface.
     46 class ChildListMutationAccumulator : public RefCounted<ChildListMutationAccumulator> {
     47 public:
     48     static PassRefPtr<ChildListMutationAccumulator> getOrCreate(Node*);
     49     ~ChildListMutationAccumulator();
     50 
     51     void childAdded(PassRefPtr<Node>);
     52     void willRemoveChild(PassRefPtr<Node>);
     53 
     54     bool hasObservers() const { return m_observers; }
     55 
     56 private:
     57     ChildListMutationAccumulator(PassRefPtr<Node>, PassOwnPtr<MutationObserverInterestGroup>);
     58 
     59     void enqueueMutationRecord();
     60     bool isEmpty();
     61     bool isAddedNodeInOrder(Node*);
     62     bool isRemovedNodeInOrder(Node*);
     63 
     64     RefPtr<Node> m_target;
     65 
     66     Vector<RefPtr<Node> > m_removedNodes;
     67     Vector<RefPtr<Node> > m_addedNodes;
     68     RefPtr<Node> m_previousSibling;
     69     RefPtr<Node> m_nextSibling;
     70     Node* m_lastAdded;
     71 
     72     OwnPtr<MutationObserverInterestGroup> m_observers;
     73 };
     74 
     75 class ChildListMutationScope {
     76     WTF_MAKE_NONCOPYABLE(ChildListMutationScope);
     77 public:
     78     explicit ChildListMutationScope(Node* target)
     79     {
     80         if (target->document()->hasMutationObserversOfType(MutationObserver::ChildList))
     81             m_accumulator = ChildListMutationAccumulator::getOrCreate(target);
     82     }
     83 
     84     void childAdded(Node* child)
     85     {
     86         if (m_accumulator && m_accumulator->hasObservers())
     87             m_accumulator->childAdded(child);
     88     }
     89 
     90     void willRemoveChild(Node* child)
     91     {
     92         if (m_accumulator && m_accumulator->hasObservers())
     93             m_accumulator->willRemoveChild(child);
     94     }
     95 
     96 private:
     97     RefPtr<ChildListMutationAccumulator> m_accumulator;
     98 };
     99 
    100 } // namespace WebCore
    101 
    102 #endif // ChildListMutationScope_h
    103