/*
* Copyright (C) 2008 Apple 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 LifecycleObserver_h
#define LifecycleObserver_h
#include "wtf/Assertions.h"
namespace WebCore {
template<typename T>
class LifecycleObserver {
public:
typedef T Context;
enum Type {
ActiveDOMObjectType,
DocumentLifecycleObserverType,
GenericType,
PageLifecycleObserverType,
DOMWindowLifecycleObserverType
};
explicit LifecycleObserver(Context* context, Type type = GenericType)
: m_lifecycleContext(context)
, m_observerType(type)
{
observeContext(context);
}
virtual ~LifecycleObserver()
{
observeContext(0);
}
virtual void contextDestroyed() { m_lifecycleContext = 0; }
Context* lifecycleContext() const { return m_lifecycleContext; }
Type observerType() const { return m_observerType; }
protected:
void observeContext(Context*);
Context* m_lifecycleContext;
Type m_observerType;
};
//
// These functions should be specialized for each LifecycleObserver instances.
//
template<typename T> void observerContext(T*, LifecycleObserver<T>*) { ASSERT_NOT_REACHED(); }
template<typename T> void unobserverContext(T*, LifecycleObserver<T>*) { ASSERT_NOT_REACHED(); }
template<typename T>
inline void LifecycleObserver<T>::observeContext(typename LifecycleObserver<T>::Context* context)
{
if (m_lifecycleContext)
unobserverContext(m_lifecycleContext, this);
m_lifecycleContext = context;
if (m_lifecycleContext)
observerContext(m_lifecycleContext, this);
}
} // namespace WebCore
#endif // LifecycleObserver_h