YooAssetScene/Assets/YooAsset/Runtime/AssetSystem/AssetOperationHandle.cs

using System.Collections;
using UnityEngine;

namespace YooAsset
{
	public struct AssetOperationHandle : IEnumerator
	{
		private IAssetProvider _provider;

		internal AssetOperationHandle(IAssetProvider provider)
		{
			_provider = provider;
		}

		/// <summary>
		/// 句柄是否有效（AssetFileLoader销毁会导致所有句柄失效）
		/// </summary>
		public bool IsValid
		{
			get
			{
				return _provider != null && _provider.IsValid;
			}
		}

		/// <summary>
		/// 当前的加载状态
		/// </summary>
		public EAssetStates States
		{
			get
			{
				if (IsValid == false)
					return EAssetStates.None;
				return _provider.States;
			}
		}

		/// <summary>
		/// 加载进度
		/// </summary>
		public float Progress
		{
			get
			{
				if (IsValid == false)
					return 0;
				return _provider.Progress;
			}
		}

		/// <summary>
		/// 是否加载完毕
		/// </summary>
		public bool IsDone
		{
			get
			{
				if (IsValid == false)
					return false;
				return _provider.IsDone;
			}
		}

		/// <summary>
		/// 完成委托
		/// </summary>
		public event System.Action<AssetOperationHandle> Completed
		{
			add
			{
				if (IsValid == false)
					throw new System.Exception($"{nameof(AssetOperationHandle)} is invalid");
				if (_provider.IsDone)
					value.Invoke(this);
				else
					_provider.Callback += value;
			}
			remove
			{
				if (IsValid == false)
					throw new System.Exception($"{nameof(AssetOperationHandle)} is invalid");
				_provider.Callback -= value;
			}
		}

		/// <summary>
		/// 资源对象
		/// </summary>
		public UnityEngine.Object AssetObject
		{
			get
			{
				if (IsValid == false)
					return null;
				return _provider.AssetObject;
			}
		}

		/// <summary>
		/// 资源对象集合
		/// </summary>
		public UnityEngine.Object[] AllAssets
		{
			get
			{
				if (IsValid == false)
					return null;
				return _provider.AllAssets;
			}
		}

		/// <summary>
		/// 扩展的实例对象
		/// </summary>
		public IAssetInstance AssetInstance
		{
			get
			{
				if (IsValid == false)
					return null;
				return _provider.AssetInstance;
			}
		}
		
		/// <summary>
		/// 初始化的游戏对象（只限于请求的资源对象类型为GameObject）
		/// </summary>
		public GameObject InstantiateObject
		{
			get
			{
				if (IsValid == false)
					return null;
				if (_provider.AssetObject == null)
					return null;
				return UnityEngine.Object.Instantiate(_provider.AssetObject as GameObject);
			}
		}

		/// <summary>
		/// 释放资源句柄
		/// </summary>
		public void Release()
		{
			if (IsValid == false)
				return;
			_provider.Release();
			_provider = null;
		}

		/// <summary>
		/// 等待异步执行完毕
		/// </summary>
		public void WaitForAsyncComplete()
		{
			if (IsValid == false)
				return;
			_provider.WaitForAsyncComplete();
		}

		#region 异步操作相关
		/// <summary>
		/// 异步操作任务
		/// </summary>
		public System.Threading.Tasks.Task<object> Task
		{
			get { return _provider.Task; }
		}

		// 协程相关
		bool IEnumerator.MoveNext()
		{
			return !IsDone;
		}
		void IEnumerator.Reset()
		{
		}
		object IEnumerator.Current
		{
			get { return AssetObject; }
		}
		#endregion
	}
}