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      1 /*
      2  * Copyright (C) 2008 Apple Inc. All Rights Reserved.
      3  * Copyright (C) 2013 Google Inc. All Rights Reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  * 1. Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  * 2. Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in the
     12  *    documentation and/or other materials provided with the distribution.
     13  *
     14  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
     15  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     17  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
     18  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     19  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     20  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     21  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
     22  * 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 LifecycleNotifier_h
     28 #define LifecycleNotifier_h
     29 
     30 #include "platform/LifecycleObserver.h"
     31 #include "wtf/HashSet.h"
     32 #include "wtf/PassOwnPtr.h"
     33 #include "wtf/TemporaryChange.h"
     34 
     35 namespace blink {
     36 
     37 template<typename T>
     38 class LifecycleNotifier {
     39 public:
     40     typedef LifecycleObserver<T> Observer;
     41     typedef T Context;
     42 
     43     static PassOwnPtr<LifecycleNotifier> create(Context* context)
     44     {
     45         return adoptPtr(new LifecycleNotifier(context));
     46     }
     47 
     48 
     49     virtual ~LifecycleNotifier();
     50 
     51 
     52     // FIXME: this won't need to be virtual anymore.
     53     virtual void addObserver(Observer*);
     54     virtual void removeObserver(Observer*);
     55 
     56     bool isIteratingOverObservers() const { return m_iterating != IteratingNone; }
     57 
     58 protected:
     59     explicit LifecycleNotifier(Context* context)
     60         : m_iterating(IteratingNone)
     61         , m_context(context)
     62     {
     63     }
     64 
     65     Context* context() const { return m_context; }
     66 
     67     enum IterationType {
     68         IteratingNone,
     69         IteratingOverAll,
     70         IteratingOverActiveDOMObjects,
     71         IteratingOverContextObservers,
     72         IteratingOverDocumentObservers,
     73         IteratingOverPageObservers,
     74         IteratingOverDOMWindowObservers
     75     };
     76 
     77     IterationType m_iterating;
     78 
     79 private:
     80     typedef HashSet<Observer*> ObserverSet;
     81 
     82     ObserverSet m_observers;
     83     Context* m_context;
     84 };
     85 
     86 template<typename T>
     87 inline LifecycleNotifier<T>::~LifecycleNotifier()
     88 {
     89     TemporaryChange<IterationType> scope(this->m_iterating, IteratingOverAll);
     90     for (typename ObserverSet::iterator it = m_observers.begin(); it != m_observers.end(); it = m_observers.begin()) {
     91         Observer* observer = *it;
     92         m_observers.remove(observer);
     93         ASSERT(observer->lifecycleContext() == m_context);
     94         observer->contextDestroyed();
     95     }
     96 }
     97 
     98 template<typename T>
     99 inline void LifecycleNotifier<T>::addObserver(typename LifecycleNotifier<T>::Observer* observer)
    100 {
    101     RELEASE_ASSERT(m_iterating != IteratingOverAll);
    102     m_observers.add(observer);
    103 }
    104 
    105 template<typename T>
    106 inline void LifecycleNotifier<T>::removeObserver(typename LifecycleNotifier<T>::Observer* observer)
    107 {
    108     RELEASE_ASSERT(m_iterating != IteratingOverAll);
    109     m_observers.remove(observer);
    110 }
    111 
    112 
    113 
    114 } // namespace blink
    115 
    116 #endif // LifecycleNotifier_h
    117