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/*
* Copyright (C) 2013-2019 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/DumbPtrTraits.h>
#include <wtf/FastMalloc.h>
#include <wtf/Noncopyable.h>
#include <wtf/Packed.h>
namespace WTF {
namespace Private {
template<typename T, typename PassedPtrTraits = DumbPtrTraits<T>>
class BagNode {
WTF_MAKE_FAST_ALLOCATED;
public:
using PtrTraits = typename PassedPtrTraits::template RebindTraits<BagNode>;
template<typename... Args>
BagNode(Args&&... args)
: m_item(std::forward<Args>(args)...)
{ }
T m_item;
typename PtrTraits::StorageType m_next { nullptr };
};
} // namespace Private
template<typename T, typename PassedPtrTraits = DumbPtrTraits<T>>
class Bag final {
WTF_MAKE_NONCOPYABLE(Bag);
WTF_MAKE_FAST_ALLOCATED;
using Node = Private::BagNode<T, PassedPtrTraits>;
using PtrTraits = typename PassedPtrTraits::template RebindTraits<Node>;
public:
Bag() = default;
template<typename U>
Bag(Bag<T, U>&& other)
{
ASSERT(!m_head);
m_head = other.unwrappedHead();
other.m_head = nullptr;
}
~Bag()
{
clear();
}
void clear()
{
Node* head = this->unwrappedHead();
while (head) {
Node* current = head;
head = Node::PtrTraits::unwrap(current->m_next);
delete current;
}
m_head = nullptr;
}
template<typename... Args>
T* add(Args&&... args)
{
Node* newNode = new Node(std::forward<Args>(args)...);
newNode->m_next = unwrappedHead();
m_head = newNode;
return &newNode->m_item;
}
class iterator {
WTF_MAKE_FAST_ALLOCATED;
public:
iterator()
: m_node(0)
{
}
// This is sort of cheating; it's equivalent to iter == end().
bool operator!() const { return !m_node; }
T* operator*() const { return &m_node->m_item; }
iterator& operator++()
{
m_node = Node::PtrTraits::unwrap(m_node->m_next);
return *this;
}
bool operator==(const iterator& other) const
{
return m_node == other.m_node;
}
bool operator!=(const iterator& other) const
{
return !(*this == other);
}
private:
template<typename, typename> friend class WTF::Bag;
Node* m_node;
};
iterator begin()
{
iterator result;
result.m_node = unwrappedHead();
return result;
}
const iterator begin() const
{
iterator result;
result.m_node = unwrappedHead();
return result;
}
iterator end() const { return iterator(); }
bool isEmpty() const { return !m_head; }
private:
Node* unwrappedHead() const { return PtrTraits::unwrap(m_head); }
typename PtrTraits::StorageType m_head { nullptr };
};
template<typename T>
using PackedBag = Bag<T, PackedPtrTraits<T>>;
} // namespace WTF
using WTF::Bag;
using WTF::PackedBag;