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/*
* Copyright (C) 2008 Apple Inc. All Rights Reserved.
* Copyright (C) 2013 Google Inc. All Rights Reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE COMPUTER, INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#ifndef LifecycleNotifier_h
#define LifecycleNotifier_h
#include "platform/LifecycleObserver.h"
#include "wtf/HashSet.h"
#include "wtf/PassOwnPtr.h"
#include "wtf/TemporaryChange.h"
namespace blink {
template<typename T>
class LifecycleNotifier {
public:
typedef LifecycleObserver<T> Observer;
typedef T Context;
static PassOwnPtr<LifecycleNotifier> create(Context* context)
{
return adoptPtr(new LifecycleNotifier(context));
}
virtual ~LifecycleNotifier();
// notifyContextDestroyed() should be explicitly dispatched from an
// observed context to notify observers contextDestroyed().
// At the point of contextDestroyed() is called, m_context is still
// valid and thus it is safe to use m_context during the notification.
virtual void notifyContextDestroyed();
// FIXME: this won't need to be virtual anymore.
virtual void addObserver(Observer*);
virtual void removeObserver(Observer*);
bool isIteratingOverObservers() const { return m_iterating != IteratingNone; }
protected:
explicit LifecycleNotifier(Context* context)
: m_iterating(IteratingNone)
, m_context(context)
, m_didCallContextDestroyed(false)
{
}
Context* context() const { return m_context; }
enum IterationType {
IteratingNone,
IteratingOverAll,
IteratingOverActiveDOMObjects,
IteratingOverDocumentObservers,
IteratingOverPageObservers,
IteratingOverDOMWindowObservers
};
IterationType m_iterating;
private:
typedef HashSet<Observer*> ObserverSet;
ObserverSet m_observers;
Context* m_context;
bool m_didCallContextDestroyed;
};
template<typename T>
inline LifecycleNotifier<T>::~LifecycleNotifier()
{
// FIXME: Enable the following ASSERT. Also see a FIXME in Document::detach().
// ASSERT(!m_observers.size() || m_didCallContextDestroyed);
TemporaryChange<IterationType> scope(this->m_iterating, IteratingOverAll);
for (Observer* observer : m_observers) {
ASSERT(observer->lifecycleContext() == m_context);
observer->clearLifecycleContext();
}
}
template<typename T>
inline void LifecycleNotifier<T>::notifyContextDestroyed()
{
// Don't notify contextDestroyed() twice.
if (m_didCallContextDestroyed)
return;
TemporaryChange<IterationType> scope(this->m_iterating, IteratingOverAll);
Vector<Observer*> snapshotOfObservers;
copyToVector(m_observers, snapshotOfObservers);
for (Observer* observer : snapshotOfObservers) {
// FIXME: Oilpan: At the moment, it's possible that the Observer is
// destructed during the iteration. Once we enable Oilpan by default
// for Observers, we can remove the hack by making m_observers
// a HeapHashSet<WeakMember<Observers>>. (i.e., we can just iterate
// m_observers without taking a snapshot).
if (m_observers.contains(observer)) {
ASSERT(observer->lifecycleContext() == m_context);
observer->contextDestroyed();
}
}
m_didCallContextDestroyed = true;
}
template<typename T>
inline void LifecycleNotifier<T>::addObserver(typename LifecycleNotifier<T>::Observer* observer)
{
RELEASE_ASSERT(m_iterating != IteratingOverAll);
m_observers.add(observer);
}
template<typename T>
inline void LifecycleNotifier<T>::removeObserver(typename LifecycleNotifier<T>::Observer* observer)
{
m_observers.remove(observer);
}
} // namespace blink
#endif // LifecycleNotifier_h
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