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       1                 :             : /*
       2                 :             :  * Copyright 2025 Jinwoo Sung
       3                 :             :  *
       4                 :             :  * Licensed under the Apache License, Version 2.0 (the "License");
       5                 :             :  * you may not use this file except in compliance with the License.
       6                 :             :  * You may obtain a copy of the License at
       7                 :             :  *
       8                 :             :  *     http://www.apache.org/licenses/LICENSE-2.0
       9                 :             :  *
      10                 :             :  * Unless required by applicable law or agreed to in writing, software
      11                 :             :  * distributed under the License is distributed on an "AS IS" BASIS,
      12                 :             :  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
      13                 :             :  * See the License for the specific language governing permissions and
      14                 :             :  * limitations under the License.
      15                 :             :  */
      16                 :             : 
      17                 :             : #pragma once
      18                 :             : 
      19                 :             : #include <atomic>
      20                 :             : 
      21                 :             : #include "wirestead/base/common.hpp"
      22                 :             : 
      23                 :             : namespace wirestead {
      24                 :             : namespace concurrency {
      25                 :             : 
      26                 :             : /**
      27                 :             :  * @brief Thread-safe atomic state wrapper
      28                 :             :  *
      29                 :             :  * Lightweight wrapper for atomic state management.
      30                 :             :  */
      31                 :             : template <typename StateType>
      32                 :             : class AtomicState {
      33                 :             :  public:
      34                 :             :   using State = StateType;
      35                 :             : 
      36                 :             :   explicit AtomicState(const State& initial_state = State{});
      37                 :             : 
      38                 :             :   State get() const noexcept;
      39                 :             :   void set(const State& new_state) noexcept;
      40                 :             :   void set(State&& new_state) noexcept;
      41                 :             : 
      42                 :             :   bool compare_and_set(const State& expected, const State& desired) noexcept;
      43                 :             :   State exchange(const State& new_state) noexcept;
      44                 :             : 
      45                 :             :   bool is_state(const State& expected_state) const noexcept;
      46                 :             : 
      47                 :             :  private:
      48                 :             :   std::atomic<State> state_;
      49                 :             : };
      50                 :             : 
      51                 :             : // Specialization for LinkState
      52                 :             : using AtomicLinkState = AtomicState<base::LinkState>;
      53                 :             : 
      54                 :             : // AtomicState template implementations
      55                 :             : template <typename StateType>
      56                 :        2108 : AtomicState<StateType>::AtomicState(const State& initial_state) : state_(initial_state) {}
      57                 :             : 
      58                 :             : template <typename StateType>
      59                 :        9132 : StateType AtomicState<StateType>::get() const noexcept {
      60                 :        9132 :   return state_.load();
      61                 :             : }
      62                 :             : 
      63                 :             : template <typename StateType>
      64                 :        4515 : void AtomicState<StateType>::set(const State& new_state) noexcept {
      65                 :        4515 :   state_.store(new_state);
      66                 :        4515 : }
      67                 :             : 
      68                 :             : template <typename StateType>
      69                 :        4891 : void AtomicState<StateType>::set(State&& new_state) noexcept {
      70                 :        4891 :   state_.store(new_state);
      71                 :        4891 : }
      72                 :             : 
      73                 :             : template <typename StateType>
      74                 :             : bool AtomicState<StateType>::compare_and_set(const State& expected, const State& desired) noexcept {
      75                 :             :   State expected_copy = expected;
      76                 :             :   return state_.compare_exchange_strong(expected_copy, desired);
      77                 :             : }
      78                 :             : 
      79                 :             : template <typename StateType>
      80                 :             : StateType AtomicState<StateType>::exchange(const State& new_state) noexcept {
      81                 :             :   return state_.exchange(new_state);
      82                 :             : }
      83                 :             : 
      84                 :             : template <typename StateType>
      85                 :     1143022 : bool AtomicState<StateType>::is_state(const State& expected_state) const noexcept {
      86                 :     1143022 :   return state_.load() == expected_state;
      87                 :             : }
      88                 :             : 
      89                 :             : }  // namespace concurrency
      90                 :             : }  // namespace wirestead