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