chromium/base/threading/sequence_local_storage_map.h

// Copyright 2017 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef BASE_THREADING_SEQUENCE_LOCAL_STORAGE_MAP_H_
#define BASE_THREADING_SEQUENCE_LOCAL_STORAGE_MAP_H_

#include "base/auto_reset.h"
#include "base/base_export.h"
#include "base/containers/flat_map.h"
#include "base/memory/raw_ptr_exclusion.h"
#include "third_party/abseil-cpp/absl/meta/type_traits.h"

namespace base {
namespace internal {

// A SequenceLocalStorageMap holds (slot_id) -> (value, destructor) items for a
// sequence. When a task runs, it is expected that a pointer to its sequence's
// SequenceLocalStorageMap is set in TLS using
// ScopedSetSequenceLocalStorageMapForCurrentThread. When a
// SequenceLocalStorageMap is destroyed, it invokes the destructors associated
// with values stored within it.
// The Get() and Set() methods should not be accessed directly.
// Use SequenceLocalStorageSlot to Get() and Set() values in the current
// sequence's SequenceLocalStorageMap.
class BASE_EXPORT SequenceLocalStorageMap { … };

// Within the scope of this object,
// SequenceLocalStorageMap::GetForCurrentThread() will return a reference to the
// SequenceLocalStorageMap object passed to the constructor. There can be only
// one ScopedSetSequenceLocalStorageMapForCurrentThread instance per scope.
class BASE_EXPORT
    [[maybe_unused,
      nodiscard]] ScopedSetSequenceLocalStorageMapForCurrentThread { … };
}  // namespace internal
}  // namespace base

#endif  // BASE_THREADING_SEQUENCE_LOCAL_STORAGE_MAP_H_