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/*
* Copyright (C) 2012,2013 Google Inc. All rights reserved.
* Copyright (C) 2014 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:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * 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.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 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 THE COPYRIGHT
* OWNER 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 CollectionItemsCache_h
#define CollectionItemsCache_h
#include "core/html/CollectionIndexCache.h"
#include "wtf/Vector.h"
#include <v8.h>
namespace blink {
template <typename Collection, typename NodeType>
class CollectionItemsCache : public CollectionIndexCache<Collection, NodeType> {
typedef CollectionIndexCache<Collection, NodeType> Base;
public:
CollectionItemsCache();
~CollectionItemsCache();
unsigned nodeCount(const Collection&);
NodeType* nodeAt(const Collection&, unsigned index);
void invalidate();
private:
ptrdiff_t allocationSize() const { return m_cachedList.capacity() * sizeof(NodeType*); }
static void reportExtraMemoryCostForCollectionItemsCache(ptrdiff_t diff)
{
v8::Isolate::GetCurrent()->AdjustAmountOfExternalAllocatedMemory(diff);
}
bool m_listValid;
Vector<NodeType*> m_cachedList;
};
template <typename Collection, typename NodeType>
CollectionItemsCache<Collection, NodeType>::CollectionItemsCache()
: m_listValid(false)
{
}
template <typename Collection, typename NodeType>
CollectionItemsCache<Collection, NodeType>::~CollectionItemsCache()
{
if (ptrdiff_t diff = allocationSize())
reportExtraMemoryCostForCollectionItemsCache(-diff);
}
template <typename Collection, typename NodeType>
void CollectionItemsCache<Collection, NodeType>::invalidate()
{
Base::invalidate();
if (m_listValid) {
m_cachedList.shrink(0);
m_listValid = false;
}
}
template <class Collection, class NodeType>
unsigned CollectionItemsCache<Collection, NodeType>::nodeCount(const Collection& collection)
{
if (this->isCachedNodeCountValid())
return this->cachedNodeCount();
NodeType* currentNode = collection.traverseToFirst();
unsigned currentIndex = 0;
ptrdiff_t oldCapacity = allocationSize();
while (currentNode) {
m_cachedList.append(currentNode);
currentNode = collection.traverseForwardToOffset(currentIndex + 1, *currentNode, currentIndex);
}
if (ptrdiff_t diff = allocationSize() - oldCapacity)
reportExtraMemoryCostForCollectionItemsCache(diff);
this->setCachedNodeCount(m_cachedList.size());
m_listValid = true;
return this->cachedNodeCount();
}
template <typename Collection, typename NodeType>
inline NodeType* CollectionItemsCache<Collection, NodeType>::nodeAt(const Collection& collection, unsigned index)
{
if (m_listValid) {
ASSERT(this->isCachedNodeCountValid());
return index < this->cachedNodeCount() ? m_cachedList[index] : 0;
}
return Base::nodeAt(collection, index);
}
} // namespace blink
#endif // CollectionItemsCache_h
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