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/*
* Copyright (C) 2009 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 INC. AND ITS CONTRIBUTORS ``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 INC. OR ITS 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 WeakGCMap_h
#define WeakGCMap_h
#include "Handle.h"
#include "JSGlobalData.h"
#include <wtf/HashMap.h>
namespace JSC {
// A HashMap for GC'd values that removes entries when the associated value
// dies.
template <typename KeyType, typename MappedType> struct DefaultWeakGCMapFinalizerCallback {
static void* finalizerContextFor(KeyType key)
{
return reinterpret_cast<void*>(key);
}
static KeyType keyForFinalizer(void* context, typename HandleTypes<MappedType>::ExternalType)
{
return reinterpret_cast<KeyType>(context);
}
};
template<typename KeyType, typename MappedType, typename FinalizerCallback = DefaultWeakGCMapFinalizerCallback<KeyType, MappedType>, typename HashArg = typename DefaultHash<KeyType>::Hash, typename KeyTraitsArg = HashTraits<KeyType> >
class WeakGCMap : private WeakHandleOwner {
WTF_MAKE_FAST_ALLOCATED;
WTF_MAKE_NONCOPYABLE(WeakGCMap);
typedef HashMap<KeyType, WeakImpl*, HashArg, KeyTraitsArg> MapType;
typedef typename HandleTypes<MappedType>::ExternalType ExternalType;
public:
WeakGCMap()
{
}
void clear()
{
typename MapType::iterator end = m_map.end();
for (typename MapType::iterator ptr = m_map.begin(); ptr != end; ++ptr)
WeakSet::deallocate(ptr->second);
m_map.clear();
}
ExternalType get(const KeyType& key) const
{
WeakImpl* impl = m_map.get(key);
if (!impl || impl->state() != WeakImpl::Live)
return ExternalType();
return HandleTypes<MappedType>::getFromSlot(const_cast<JSValue*>(&impl->jsValue()));
}
void set(JSGlobalData&, const KeyType& key, ExternalType value)
{
typename MapType::AddResult result = m_map.add(key, 0);
if (!result.isNewEntry)
WeakSet::deallocate(result.iterator->second);
result.iterator->second = WeakSet::allocate(value, this, FinalizerCallback::finalizerContextFor(key));
}
void remove(const KeyType& key)
{
WeakImpl* impl = m_map.take(key);
if (!impl)
return;
WeakSet::deallocate(impl);
}
~WeakGCMap()
{
clear();
}
private:
virtual void finalize(Handle<Unknown> handle, void* context)
{
WeakImpl* impl = m_map.take(FinalizerCallback::keyForFinalizer(context, HandleTypes<MappedType>::getFromSlot(handle.slot())));
ASSERT(impl);
WeakSet::deallocate(impl);
}
MapType m_map;
};
} // namespace JSC
#endif // WeakGCMap_h
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