| /* |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| namespace DotPulsar.Internal |
| { |
| using Abstractions; |
| using System.Threading; |
| using System.Threading.Tasks; |
| |
| public sealed class StateManager<TState> : IStateManager<TState> where TState : notnull |
| { |
| private readonly object _lock; |
| private readonly StateTaskCollection<TState> _stateTasks; |
| private readonly TState[] _finalStates; |
| |
| public StateManager(TState initialState, params TState[] finalStates) |
| { |
| _lock = new object(); |
| _stateTasks = new StateTaskCollection<TState>(); |
| _finalStates = finalStates; |
| CurrentState = initialState; |
| } |
| |
| public TState CurrentState { get; private set; } |
| |
| public TState SetState(TState state) |
| { |
| lock (_lock) |
| { |
| if (IsFinalState(CurrentState) || CurrentState.Equals(state)) |
| return CurrentState; |
| |
| var formerState = CurrentState; |
| CurrentState = state; |
| |
| if (IsFinalState(CurrentState)) |
| _stateTasks.CompleteAllTasks(CurrentState); |
| else |
| _stateTasks.CompleteTasksAwaiting(CurrentState); |
| |
| return formerState; |
| } |
| } |
| |
| public ValueTask<TState> StateChangedTo(TState state, CancellationToken cancellationToken) |
| { |
| lock (_lock) |
| { |
| if (IsFinalState(CurrentState) || CurrentState.Equals(state)) |
| return new ValueTask<TState>(CurrentState); |
| return new ValueTask<TState>(_stateTasks.CreateTaskFor(state, StateChanged.To, cancellationToken)); |
| } |
| } |
| |
| public ValueTask<TState> StateChangedFrom(TState state, CancellationToken cancellationToken) |
| { |
| lock (_lock) |
| { |
| if (IsFinalState(CurrentState) || !CurrentState.Equals(state)) |
| return new ValueTask<TState>(CurrentState); |
| return new ValueTask<TState>(_stateTasks.CreateTaskFor(state, StateChanged.From, cancellationToken)); |
| } |
| } |
| |
| public bool IsFinalState(TState state) |
| { |
| for (var i = 0; i < _finalStates.Length; ++i) |
| { |
| if (_finalStates[i].Equals(state)) |
| return true; |
| } |
| |
| return false; |
| } |
| |
| public bool IsFinalState() |
| => IsFinalState(CurrentState); |
| } |
| } |