1*d9f75844SAndroid Build Coastguard Worker /* 2*d9f75844SAndroid Build Coastguard Worker * Copyright (c) 2021 The WebRTC project authors. All Rights Reserved. 3*d9f75844SAndroid Build Coastguard Worker * 4*d9f75844SAndroid Build Coastguard Worker * Use of this source code is governed by a BSD-style license 5*d9f75844SAndroid Build Coastguard Worker * that can be found in the LICENSE file in the root of the source 6*d9f75844SAndroid Build Coastguard Worker * tree. An additional intellectual property rights grant can be found 7*d9f75844SAndroid Build Coastguard Worker * in the file PATENTS. All contributing project authors may 8*d9f75844SAndroid Build Coastguard Worker * be found in the AUTHORS file in the root of the source tree. 9*d9f75844SAndroid Build Coastguard Worker */ 10*d9f75844SAndroid Build Coastguard Worker 11*d9f75844SAndroid Build Coastguard Worker // This implementation is borrowed from Chromium. 12*d9f75844SAndroid Build Coastguard Worker 13*d9f75844SAndroid Build Coastguard Worker #ifndef RTC_BASE_CONTAINERS_IDENTITY_H_ 14*d9f75844SAndroid Build Coastguard Worker #define RTC_BASE_CONTAINERS_IDENTITY_H_ 15*d9f75844SAndroid Build Coastguard Worker 16*d9f75844SAndroid Build Coastguard Worker #include <utility> 17*d9f75844SAndroid Build Coastguard Worker 18*d9f75844SAndroid Build Coastguard Worker namespace webrtc { 19*d9f75844SAndroid Build Coastguard Worker 20*d9f75844SAndroid Build Coastguard Worker // Implementation of C++20's std::identity. 21*d9f75844SAndroid Build Coastguard Worker // 22*d9f75844SAndroid Build Coastguard Worker // Reference: 23*d9f75844SAndroid Build Coastguard Worker // - https://en.cppreference.com/w/cpp/utility/functional/identity 24*d9f75844SAndroid Build Coastguard Worker // - https://wg21.link/func.identity 25*d9f75844SAndroid Build Coastguard Worker struct identity { 26*d9f75844SAndroid Build Coastguard Worker template <typename T> operatoridentity27*d9f75844SAndroid Build Coastguard Worker constexpr T&& operator()(T&& t) const noexcept { 28*d9f75844SAndroid Build Coastguard Worker return std::forward<T>(t); 29*d9f75844SAndroid Build Coastguard Worker } 30*d9f75844SAndroid Build Coastguard Worker 31*d9f75844SAndroid Build Coastguard Worker using is_transparent = void; 32*d9f75844SAndroid Build Coastguard Worker }; 33*d9f75844SAndroid Build Coastguard Worker 34*d9f75844SAndroid Build Coastguard Worker } // namespace webrtc 35*d9f75844SAndroid Build Coastguard Worker 36*d9f75844SAndroid Build Coastguard Worker #endif // RTC_BASE_CONTAINERS_IDENTITY_H_ 37