JisolGame/JNFrame2/Assets/JNGame/Util/UnityMainThreadDispatcher.cs

using System;
using System.Collections;
using System.Collections.Generic;
using System.Threading.Tasks;

namespace JNGame.Util
{
    /// Author: Pim de Witte (pimdewitte.com) and contributors, https://github.com/PimDeWitte/UnityMainThreadDispatcher
	/// <summary>
	/// A thread-safe class which holds a queue with actions to execute on the next Update() method. It can be used to make calls to the main thread for
	/// things such as UI Manipulation in Unity. It was developed for use in combination with the Firebase Unity plugin, which uses separate threads for event handling
	/// </summary>
	public class UnityMainThreadDispatcher : SingletonScene<UnityMainThreadDispatcher> {

		private readonly Queue<Action> _executionQueue = new Queue<Action>();

		public void Update() {
			lock(_executionQueue) {
				while (_executionQueue.Count > 0) {
					_executionQueue.Dequeue().Invoke();
				}
			}
		}

		/// <summary>
		/// Locks the queue and adds the IEnumerator to the queue
		/// </summary>
		/// <param name="action">IEnumerator function that will be executed from the main thread.</param>
		public void Enqueue(IEnumerator action) {
			lock (_executionQueue) {
				_executionQueue.Enqueue (() => {
					StartCoroutine(action);
				});
			}
		}

		/// <summary>
		/// Locks the queue and adds the Action to the queue
		/// </summary>
		/// <param name="action">function that will be executed from the main thread.</param>
		public void Enqueue(Action action)
		{
			Enqueue(ActionWrapper(action));
		}

		/// <summary>
		/// Locks the queue and adds the Action to the queue, returning a Task which is completed when the action completes
		/// </summary>
		/// <param name="action">function that will be executed from the main thread.</param>
		/// <returns>A Task that can be awaited until the action completes</returns>
		public Task EnqueueAsync(Action action)
		{
			var tcs = new TaskCompletionSource<bool>();

			void WrappedAction() {
				try 
				{
					action();
					tcs.TrySetResult(true);
				} catch (Exception ex) 
				{
					tcs.TrySetException(ex);
				}
			}

			Enqueue(ActionWrapper(WrappedAction));
			return tcs.Task;
		}


		IEnumerator ActionWrapper(Action a)
		{
			a();
			yield return null;
		}

    }
}