chromium/third_party/blink/renderer/platform/peerconnection/two_keys_adapter_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 THIRD_PARTY_BLINK_RENDERER_PLATFORM_PEERCONNECTION_TWO_KEYS_ADAPTER_MAP_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_PEERCONNECTION_TWO_KEYS_ADAPTER_MAP_H_

#include <memory>
#include <optional>
#include <utility>

#include "base/check.h"
#include "base/containers/contains.h"
#include "base/not_fatal_until.h"
#include "third_party/blink/renderer/platform/wtf/hash_map.h"

namespace blink {

// A map with up to two keys per entry. An element is inserted with a key, this
// is the primary key. A secondary key can optionally be set to the same entry
// and it may be set at a later point in time than the element was inserted. For
// lookup and erasure both keys can be used.
//
// This was designed to assist the implementation of adapter maps. The adapters
// are the glue between the blink and webrtc layer objects. The adapter maps
// keep track of which blink and webrtc layer objects have which associated
// adapter. This requires two keys per adapter entry: something that can be used
// for lookup based on a webrtc layer object and something that can be used for
// lookup based on a blink layer object. The primary key is based on the
// webrtc/blink object that was used to create the adapter and the secondary key
// is based on the resulting blink/webrtc object after the adapter has been
// initialized.
template <typename PrimaryKey, typename SecondaryKey, typename Value>
class TwoKeysAdapterMap { … };

}  // namespace blink

#endif  // THIRD_PARTY_BLINK_RENDERER_PLATFORM_PEERCONNECTION_TWO_KEYS_ADAPTER_MAP_H_