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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 WebCore {
     36 
     37 template<typename T> class LifecycleContext;
     38 
     39 template<typename T>
     40 class LifecycleNotifier {
     41 public:
     42     typedef LifecycleObserver<T> Observer;
     43     typedef T Context;
     44 
     45     static PassOwnPtr<LifecycleNotifier> create(Context* context)
     46     {
     47         return adoptPtr(new LifecycleNotifier(context));
     48     }
     49 
     50 
     51     virtual ~LifecycleNotifier();
     52 
     53 
     54     // FIXME: this won't need to be virtual anymore.
     55     virtual void addObserver(Observer*);
     56     virtual void removeObserver(Observer*);
     57 
     58     bool isIteratingOverObservers() const { return m_iterating != IteratingNone; }
     59 
     60 protected:
     61     explicit LifecycleNotifier(Context* context)
     62         : m_iterating(IteratingNone)
     63         , m_context(context)
     64     {
     65     }
     66 
     67     Context* context() const { return m_context; }
     68 
     69     enum IterationType {
     70         IteratingNone,
     71         IteratingOverAll,
     72         IteratingOverActiveDOMObjects,
     73         IteratingOverContextObservers,
     74         IteratingOverDocumentObservers,
     75         IteratingOverPageObservers,
     76         IteratingOverDOMWindowObservers
     77     };
     78 
     79     IterationType m_iterating;
     80 
     81 private:
     82     typedef HashSet<Observer*> ObserverSet;
     83 
     84     ObserverSet m_observers;
     85     Context* m_context;
     86 };
     87 
     88 template<typename T>
     89 inline LifecycleNotifier<T>::~LifecycleNotifier()
     90 {
     91     TemporaryChange<IterationType> scope(this->m_iterating, IteratingOverAll);
     92     for (typename ObserverSet::iterator it = m_observers.begin(); it != m_observers.end(); it = m_observers.begin()) {
     93         Observer* observer = *it;
     94         m_observers.remove(observer);
     95         ASSERT(observer->lifecycleContext() == m_context);
     96         observer->contextDestroyed();
     97     }
     98 }
     99 
    100 template<typename T>
    101 inline void LifecycleNotifier<T>::addObserver(typename LifecycleNotifier<T>::Observer* observer)
    102 {
    103     RELEASE_ASSERT(m_iterating != IteratingOverAll);
    104     m_observers.add(observer);
    105 }
    106 
    107 template<typename T>
    108 inline void LifecycleNotifier<T>::removeObserver(typename LifecycleNotifier<T>::Observer* observer)
    109 {
    110     RELEASE_ASSERT(m_iterating != IteratingOverAll);
    111     m_observers.remove(observer);
    112 }
    113 
    114 
    115 
    116 } // namespace WebCore
    117 
    118 #endif // LifecycleNotifier_h
    119