chromium/v8/src/base/threaded-list.h

// Copyright 2018 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef V8_BASE_THREADED_LIST_H_
#define V8_BASE_THREADED_LIST_H_

#include <iterator>

#include "src/base/compiler-specific.h"
#include "src/base/macros.h"

namespace v8 {
namespace base {

template <typename T>
struct ThreadedListTraits { … };

// Represents a linked list that threads through the nodes in the linked list.
// Entries in the list are pointers to nodes. By default nodes need to have a
// T** next() method that returns the location where the next value is stored.
// The kSupportsUnsafeInsertion flag defines whether the list supports insertion
// of new elements into the list by just rewiring the next pointers without
// updating the list object itself. Such an insertion might invalidate the
// pointer to list tail and thus requires additional steps to recover the
// pointer to the tail.
// The default can be overwritten by providing a ThreadedTraits class.
template <typename T, typename BaseClass,
          typename TLTraits = ThreadedListTraits<T>,
          bool kSupportsUnsafeInsertion = false>
class ThreadedListBase final : public BaseClass { … };

struct EmptyBase { … };

// Check ThreadedListBase::EnsureValidTail.
static constexpr bool kUnsafeInsertion = …;

template <typename T, typename TLTraits = ThreadedListTraits<T>>
using ThreadedList = ThreadedListBase<T, EmptyBase, TLTraits>;

ThreadedListWithUnsafeInsertions;

}  // namespace base
}  // namespace v8

#endif  // V8_BASE_THREADED_LIST_H_