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/*
* Copyright (C) 2009, 2015-2016 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.
*/
#pragma once
#include "DeferGC.h"
#include "Weak.h"
#include "WeakGCHashTable.h"
#include <wtf/HashMap.h>
namespace JSC {
// A UncheckedKeyHashMap with Weak<JSCell> values, which automatically removes values once they're garbage collected.
template<typename KeyArg, typename ValueArg, typename HashArg = DefaultHash<KeyArg>, typename KeyTraitsArg = HashTraits<KeyArg>>
class WeakGCMap final : public WeakGCHashTable {
WTF_MAKE_FAST_ALLOCATED;
typedef Weak<ValueArg> ValueType;
typedef UncheckedKeyHashMap<KeyArg, ValueType, HashArg, KeyTraitsArg> HashMapType;
public:
typedef typename HashMapType::KeyType KeyType;
typedef typename HashMapType::AddResult AddResult;
typedef typename HashMapType::iterator iterator;
typedef typename HashMapType::const_iterator const_iterator;
explicit WeakGCMap(VM&);
~WeakGCMap() final;
ValueArg* get(const KeyType& key) const
{
return m_map.get(key);
}
AddResult set(const KeyType& key, ValueType value)
{
return m_map.set(key, WTFMove(value));
}
template<typename Functor>
ValueArg* ensureValue(const KeyType& key, Functor&& functor)
{
// If functor invokes GC, GC can prune WeakGCMap, and manipulate UncheckedKeyHashMap while we are touching it in ensure function.
// The functor must not invoke GC.
AssertNoGC assertNoGC;
AddResult result = m_map.ensure(key, std::forward<Functor>(functor));
ValueArg* value = result.iterator->value.get();
if (!result.isNewEntry && !value) {
value = functor();
result.iterator->value = WTFMove(value);
}
return value;
}
bool remove(const KeyType& key)
{
return m_map.remove(key);
}
void clear()
{
m_map.clear();
}
bool isEmpty() const
{
const_iterator it = m_map.begin();
const_iterator end = m_map.end();
while (it != end) {
if (it->value)
return true;
}
return false;
}
inline iterator find(const KeyType& key);
inline const_iterator find(const KeyType& key) const;
inline bool contains(const KeyType& key) const;
void pruneStaleEntries() final;
template<typename Func>
void forEach(Func);
private:
HashMapType m_map;
VM& m_vm;
};
} // namespace JSC
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