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/*
* Copyright (C) 2003-2020 Apple Inc. All rights reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public License
* along with this library; see the file COPYING.LIB. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*
*/
#pragma once
#include <wtf/HashTraits.h>
#include <wtf/Ref.h>
namespace WTF {
template <typename T>
class DataRef {
public:
DataRef(Ref<T>&& data)
: m_data(WTFMove(data))
{
}
DataRef(const DataRef& other)
: m_data(other.m_data.copyRef())
{
}
DataRef& operator=(const DataRef& other)
{
m_data = other.m_data.copyRef();
return *this;
}
DataRef(DataRef&&) = default;
DataRef& operator=(DataRef&&) = default;
DataRef replace(DataRef&& other)
{
return m_data.replace(WTFMove(other.m_data));
}
operator const T&() const
{
return m_data;
}
const T* ptr() const
{
return m_data.ptr();
}
const T& get() const
{
return m_data;
}
const T& operator*() const
{
return m_data;
}
const T* operator->() const
{
return m_data.ptr();
}
T& access()
{
if (!m_data->hasOneRef())
m_data = m_data->copy();
return m_data;
}
bool operator==(const DataRef& other) const
{
return m_data.ptr() == other.m_data.ptr() || m_data.get() == other.m_data.get();
}
DataRef(HashTableDeletedValueType)
: m_data(HashTableDeletedValue)
{
}
bool isHashTableDeletedValue() const { return m_data.isHashTableDeletedValue(); }
DataRef(HashTableEmptyValueType)
: m_data(HashTableEmptyValue)
{
}
bool isHashTableEmptyValue() const { return m_data.isHashTableEmptyValue(); }
static T* hashTableEmptyValue() { return nullptr; }
private:
Ref<T> m_data;
};
template<typename T> struct HashTraits<DataRef<T>> : SimpleClassHashTraits<DataRef<T>> {
static constexpr bool emptyValueIsZero = true;
static DataRef<T> emptyValue() { return HashTableEmptyValue; }
template <typename>
static void constructEmptyValue(DataRef<T>& slot)
{
new (NotNull, std::addressof(slot)) DataRef<T>(HashTableEmptyValue);
}
static constexpr bool hasIsEmptyValueFunction = true;
static bool isEmptyValue(const DataRef<T>& value) { return value.isHashTableEmptyValue(); }
};
} // namespace WTF
using WTF::DataRef;
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