#ifndef WeakGCMap_h
#define WeakGCMap_h
#include <heap/Weak.h>
#include <heap/WeakInlines.h>
#include <wtf/HashMap.h>
namespace JSC {
template<typename KeyArg, typename RawMappedArg, typename HashArg = typename DefaultHash<KeyArg>::Hash,
typename KeyTraitsArg = HashTraits<KeyArg> >
class WeakGCMap : public HashMap<KeyArg, Weak<RawMappedArg>, HashArg, KeyTraitsArg> {
typedef Weak<RawMappedArg> MappedType;
typedef HashMap<KeyArg, MappedType, HashArg, KeyTraitsArg> Base;
typedef WeakGCMap<KeyArg, RawMappedArg, HashArg, KeyTraitsArg> Self;
typedef HashTraits<MappedType> MappedTraits;
typedef typename MappedTraits::PassInType MappedPassInType;
public:
typedef typename Base::KeyType KeyType;
typedef typename Base::AddResult AddResult;
typedef typename Base::iterator iterator;
typedef typename Base::const_iterator const_iterator;
using Base::begin;
using Base::end;
using Base::size;
using Base::remove;
WeakGCMap()
: m_gcThreshold(minGCThreshold)
{
}
AddResult set(const KeyType& key, MappedPassInType value)
{
gcMapIfNeeded();
return Base::set(key, value);
}
AddResult add(const KeyType& key, MappedPassInType value)
{
gcMapIfNeeded();
AddResult addResult = Base::add(key, nullptr);
if (!addResult.iterator->value) { addResult.isNewEntry = true;
addResult.iterator->value = value;
}
return addResult;
}
iterator find(const KeyType& key)
{
iterator it = Base::find(key);
iterator end = Base::end();
if (it != end && !it->value) return end;
return it;
}
const_iterator find(const KeyType& key) const
{
return const_cast<Self*>(this)->find(key);
}
bool contains(const KeyType& key) const
{
return find(key) != end();
}
private:
static const int minGCThreshold = 3;
void gcMap()
{
Vector<KeyType, 4> zombies;
iterator end = this->end();
for (iterator it = begin(); it != end; ++it) {
if (!it->value)
zombies.append(it->key);
}
for (size_t i = 0; i < zombies.size(); ++i)
remove(zombies[i]);
}
void gcMapIfNeeded()
{
if (size() < m_gcThreshold)
return;
gcMap();
m_gcThreshold = std::max(minGCThreshold, size() * 2 - 1);
}
int m_gcThreshold;
};
template<typename KeyArg, typename RawMappedArg, typename HashArg, typename KeyTraitsArg>
const int WeakGCMap<KeyArg, RawMappedArg, HashArg, KeyTraitsArg>::minGCThreshold;
}
#endif // WeakGCMap_h