Update DownloadSystem

Assets/YooAsset/Runtime/DownloadSystem/Downloader/DownloaderBase.cs

@@ -0,0 +1,119 @@
+
+namespace YooAsset
+{
+	internal abstract class DownloaderBase
+	{
+		protected enum ESteps
+		{
+			None,
+			CreateDownload,
+			CheckDownload,
+			TryAgain,
+			Succeed,
+			Failed,
+		}
+
+		protected readonly BundleInfo _bundleInfo;
+
+		protected ESteps _steps = ESteps.None;
+
+		protected int _timeout;
+		protected int _failedTryAgain;
+		protected int _requestCount;
+		protected string _requestURL;
+
+		protected string _lastError = string.Empty;
+		protected float _downloadProgress = 0f;
+		protected ulong _downloadedBytes = 0;
+
+
+		/// <summary>
+		/// 下载进度（0-100f）
+		/// </summary>
+		public float DownloadProgress
+		{
+			get { return _downloadProgress; }
+		}
+
+		/// <summary>
+		/// 已经下载的总字节数
+		/// </summary>
+		public ulong DownloadedBytes
+		{
+			get { return _downloadedBytes; }
+		}
+
+
+		public DownloaderBase(BundleInfo bundleInfo)
+		{
+			_bundleInfo = bundleInfo;
+		}
+		public void SendRequest(int failedTryAgain, int timeout)
+		{
+			if (string.IsNullOrEmpty(_bundleInfo.LocalPath))
+				throw new System.ArgumentNullException();
+
+			if (_steps == ESteps.None)
+			{
+				_failedTryAgain = failedTryAgain;
+				_timeout = timeout;
+				_steps = ESteps.CreateDownload;
+			}
+		}
+		public abstract void Update();
+		public abstract void Abort();
+		
+		/// <summary>
+		/// 获取网络请求地址
+		/// </summary>
+		protected string GetRequestURL()
+		{
+			// 轮流返回请求地址
+			_requestCount++;
+			if (_requestCount % 2 == 0)
+				return _bundleInfo.RemoteFallbackURL;
+			else
+				return _bundleInfo.RemoteMainURL;
+		}
+
+		/// <summary>
+		/// 获取资源包信息
+		/// </summary>
+		public BundleInfo GetBundleInfo()
+		{
+			return _bundleInfo;
+		}
+
+		/// <summary>
+		/// 检测下载器是否已经完成（无论成功或失败）
+		/// </summary>
+		public bool IsDone()
+		{
+			return _steps == ESteps.Succeed || _steps == ESteps.Failed;
+		}
+
+		/// <summary>
+		/// 下载过程是否发生错误
+		/// </summary>
+		public bool HasError()
+		{
+			return _steps == ESteps.Failed;
+		}
+
+		/// <summary>
+		/// 报告错误信息
+		/// </summary>
+		public void ReportError()
+		{
+			YooLogger.Error($"Failed to download : {_requestURL} Error : {_lastError}");
+		}
+
+		/// <summary>
+		/// 获取最近一条错误日志
+		/// </summary>
+		public string GetLastError()
+		{
+			return _lastError;
+		}
+	}
+}