Home | History | Annotate | Download | only in platform 
      1 
      2 /*
      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 
     28 #ifndef LifecycleContext_h
     29 #define LifecycleContext_h
     30 
     31 #include "platform/LifecycleNotifier.h"
     32 #include "platform/LifecycleObserver.h"
     33 #include "wtf/HashSet.h"
     34 #include "wtf/OwnPtr.h"
     35 #include "wtf/PassOwnPtr.h"
     36 
     37 namespace WebCore {
     38 
     39 template <typename T>
     40 class LifecycleContext {
     41 public:
     42     typedef LifecycleNotifier<T> Notifier;
     43     typedef LifecycleObserver<T> Observer;
     44 
     45     LifecycleContext() { }
     46     virtual ~LifecycleContext() { }
     47 
     48     virtual bool isContextThread() const { return true; }
     49 
     50     // Called from the constructor of observers.
     51     void wasObservedBy(Observer*);
     52 
     53     // Called from the destructor of observers.
     54     void wasUnobservedBy(Observer*);
     55 
     56 protected:
     57     Notifier& lifecycleNotifier();
     58 
     59 private:
     60     PassOwnPtr<Notifier> createLifecycleNotifier();
     61 
     62     OwnPtr<Notifier> m_lifecycleNotifier;
     63 };
     64 
     65 template<typename T>
     66 inline void LifecycleContext<T>::wasObservedBy(typename LifecycleContext<T>::Observer* observer)
     67 {
     68     ASSERT(isContextThread());
     69     lifecycleNotifier().addObserver(observer);
     70 }
     71 
     72 template<typename T>
     73 inline void LifecycleContext<T>::wasUnobservedBy(typename LifecycleContext<T>::Observer* observer)
     74 {
     75     ASSERT(isContextThread());
     76     lifecycleNotifier().removeObserver(observer);
     77 }
     78 
     79 template<typename T>
     80 inline typename LifecycleContext<T>::Notifier& LifecycleContext<T>::lifecycleNotifier()
     81 {
     82     if (!m_lifecycleNotifier)
     83         m_lifecycleNotifier = static_cast<T*>(this)->createLifecycleNotifier();
     84     return *m_lifecycleNotifier;
     85 }
     86 
     87 template<typename T>
     88 inline PassOwnPtr<typename LifecycleContext<T>::Notifier> LifecycleContext<T>::createLifecycleNotifier()
     89 {
     90     return LifecycleContext<T>::Notifier::create(static_cast<T*>(this));
     91 }
     92 
     93 } // namespace WebCore
     94 
     95 #endif // LifecycleContext_h
     96