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      1 /*
      2  * Copyright (C) 2013 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  *     * Neither the name of Google Inc. nor the names of its
     11  * contributors may be used to endorse or promote products derived from
     12  * this software without specific prior written permission.
     13  *
     14  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     15  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     16  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     17  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     18  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     19  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     20  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     24  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     25  */
     26 
     27 #ifndef NodeChildRemovalTracker_h
     28 #define NodeChildRemovalTracker_h
     29 
     30 #include "core/dom/Node.h"
     31 #include "platform/heap/Handle.h"
     32 
     33 namespace blink {
     34 
     35 class NodeChildRemovalTracker {
     36     STACK_ALLOCATED();
     37 public:
     38     explicit NodeChildRemovalTracker(Node&);
     39     ~NodeChildRemovalTracker();
     40 
     41     static bool isBeingRemoved(Node*);
     42 
     43 private:
     44     Node& node() const { return *m_node; }
     45     NodeChildRemovalTracker* previous() { return m_previous; }
     46 
     47     RawPtrWillBeMember<Node> m_node;
     48     // Using raw pointers are safe because these NodeChildRemovalTrackers are
     49     // guaranteed to be on a stack.
     50     NodeChildRemovalTracker* m_previous;
     51     static NodeChildRemovalTracker* s_last;
     52 };
     53 
     54 inline NodeChildRemovalTracker::NodeChildRemovalTracker(Node& node)
     55     : m_node(node)
     56     , m_previous(s_last)
     57 {
     58     s_last = this;
     59 }
     60 
     61 inline NodeChildRemovalTracker::~NodeChildRemovalTracker()
     62 {
     63     s_last = m_previous;
     64 }
     65 
     66 inline bool NodeChildRemovalTracker::isBeingRemoved(Node* node)
     67 {
     68     for (NodeChildRemovalTracker* removal = s_last; removal; removal = removal->previous()) {
     69         if (removal->node().containsIncludingShadowDOM(node))
     70             return true;
     71     }
     72 
     73     return false;
     74 }
     75 
     76 } // namespace
     77 
     78 #endif
     79