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/*
* Copyright (C) 2017-2020 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 <wtf/Algorithms.h>
#include <wtf/HashSet.h>
#include <wtf/WeakPtr.h>
namespace WTF {
template<typename T, typename Counter = EmptyCounter>
class WeakHashSet final {
WTF_MAKE_FAST_ALLOCATED;
public:
typedef HashSet<Ref<WeakPtrImpl<Counter>>> WeakPtrImplSet;
typedef typename WeakPtrImplSet::AddResult AddResult;
class WeakHashSetConstIterator {
public:
using iterator_category = std::forward_iterator_tag;
using value_type = T;
using difference_type = ptrdiff_t;
using pointer = const value_type*;
using reference = const value_type&;
private:
WeakHashSetConstIterator(const WeakPtrImplSet& set, typename WeakPtrImplSet::const_iterator position)
: m_position(position), m_endPosition(set.end())
{
skipEmptyBuckets();
}
public:
T* get() const { return static_cast<T*>((*m_position)->template get<T>()); }
T& operator*() const { return *get(); }
T* operator->() const { return get(); }
WeakHashSetConstIterator& operator++()
{
ASSERT(m_position != m_endPosition);
++m_position;
skipEmptyBuckets();
return *this;
}
void skipEmptyBuckets()
{
while (m_position != m_endPosition && !get())
++m_position;
}
bool operator==(const WeakHashSetConstIterator& other) const
{
return m_position == other.m_position;
}
bool operator!=(const WeakHashSetConstIterator& other) const
{
return m_position != other.m_position;
}
private:
template <typename, typename> friend class WeakHashSet;
typename WeakPtrImplSet::const_iterator m_position;
typename WeakPtrImplSet::const_iterator m_endPosition;
};
typedef WeakHashSetConstIterator const_iterator;
WeakHashSet() { }
const_iterator begin() const { return WeakHashSetConstIterator(m_set, m_set.begin()); }
const_iterator end() const { return WeakHashSetConstIterator(m_set, m_set.end()); }
template <typename U>
AddResult add(const U& value)
{
return m_set.add(*static_cast<const T&>(value).weakPtrFactory().template createWeakPtr<T>(const_cast<U&>(value)).m_impl);
}
template <typename U>
bool remove(const U& value)
{
auto& weakPtrImpl = value.weakPtrFactory().m_impl;
if (!weakPtrImpl || !*weakPtrImpl)
return false;
return m_set.remove(*weakPtrImpl);
}
void clear() { m_set.clear(); }
template <typename U>
bool contains(const U& value) const
{
auto& weakPtrImpl = value.weakPtrFactory().m_impl;
if (!weakPtrImpl || !*weakPtrImpl)
return false;
return m_set.contains(*weakPtrImpl);
}
unsigned capacity() const { return m_set.capacity(); }
bool computesEmpty() const { return begin() == end(); }
bool hasNullReferences() const
{
return WTF::anyOf(m_set, [] (auto& value) { return !value.get(); });
}
unsigned computeSize() const
{
const_cast<WeakPtrImplSet&>(m_set).removeIf([] (auto& value) { return !value.get(); });
return m_set.size();
}
void forEach(const Function<void(T&)>& callback)
{
auto items = map(m_set, [](const Ref<WeakPtrImpl<Counter>>& item) {
auto* pointer = static_cast<T*>(item->template get<T>());
return WeakPtr { pointer };
});
for (auto& item : items) {
if (item && m_set.contains(*item.m_impl))
callback(*item);
}
}
#if ASSERT_ENABLED
void checkConsistency() const { m_set.checkConsistency(); }
#else
void checkConsistency() const { }
#endif
private:
WeakPtrImplSet m_set;
};
template<typename MapFunction, typename T>
struct Mapper<MapFunction, const WeakHashSet<T> &, void> {
using SourceItemType = T&;
using DestinationItemType = typename std::invoke_result<MapFunction, SourceItemType&>::type;
static Vector<DestinationItemType> map(const WeakHashSet<T>& source, const MapFunction& mapFunction)
{
Vector<DestinationItemType> result;
result.reserveInitialCapacity(source.computeSize());
for (auto& item : source)
result.uncheckedAppend(mapFunction(item));
return result;
}
};
template<typename T>
inline auto copyToVector(const WeakHashSet<T>& collection) -> Vector<WeakPtr<T>>
{
return WTF::map(collection, [] (auto& v) -> WeakPtr<T> { return WeakPtr<T> { v }; });
}
} // namespace WTF
using WTF::WeakHashSet;