update download system

优化资源文件下载流程。

Assets/YooAsset/Runtime/CacheSystem/CacheSystem.cs

@@ -73,9 +73,9 @@ namespace YooAsset
 		}
 
 		/// <summary>
-		/// 验证并缓存补丁包文件
+		/// 验证并缓存本地文件
 		/// </summary>
-		public static EVerifyResult VerifyAndCacheBundle(PatchBundle patchBundle, EVerifyLevel verifyLevel)
+		public static EVerifyResult VerifyAndCacheLocalBundleFile(PatchBundle patchBundle, EVerifyLevel verifyLevel)
 		{
 			var verifyResult = VerifyContentInternal(patchBundle.CachedFilePath, patchBundle.FileSize, patchBundle.FileCRC, verifyLevel);
 			if (verifyResult == EVerifyResult.Succeed)
@@ -83,10 +83,41 @@ namespace YooAsset
 			return verifyResult;
 		}
 
+		/// <summary>
+		/// 验证并缓存下载文件
+		/// </summary>
+		public static EVerifyResult VerifyAndCacheDownloadBundleFile(PatchBundle patchBundle, EVerifyLevel verifyLevel)
+		{
+			string tempFilePath = patchBundle.CachedFilePath + ".temp";
+			var verifyResult = VerifyContentInternal(tempFilePath, patchBundle.FileSize, patchBundle.FileCRC, verifyLevel);
+			if (verifyResult == EVerifyResult.Succeed)
+			{
+				try
+				{
+					string destFilePath = patchBundle.CachedFilePath;
+					if (File.Exists(destFilePath))
+						File.Delete(destFilePath);
+
+					FileInfo fileInfo = new FileInfo(tempFilePath);
+					fileInfo.MoveTo(destFilePath);
+				}
+				catch (Exception)
+				{
+					verifyResult = EVerifyResult.FileMoveFailed;
+				}
+
+				if (verifyResult == EVerifyResult.Succeed)
+				{
+					CacheBundle(patchBundle);
+				}
+			}
+			return verifyResult;
+		}
+
 		/// <summary>
 		/// 验证文件完整性
 		/// </summary>
-		public static EVerifyResult VerifyContentInternal(string filePath, long fileSize, string fileCRC, EVerifyLevel verifyLevel)
+		private static EVerifyResult VerifyContentInternal(string filePath, long fileSize, string fileCRC, EVerifyLevel verifyLevel)
 		{
 			try
 			{

Assets/YooAsset/Runtime/CacheSystem/CacheVerifier.cs

@@ -161,7 +161,7 @@ namespace YooAsset
 
 		private void VerifyFileWithoutThread(VerifyInfo verifyIno)
 		{
-			var verifyResult = CacheSystem.VerifyAndCacheBundle(verifyIno.VerifyBundle, CacheSystem.InitVerifyLevel);
+			var verifyResult = CacheSystem.VerifyAndCacheLocalBundleFile(verifyIno.VerifyBundle, CacheSystem.InitVerifyLevel);
 			if (verifyResult == EVerifyResult.Succeed)
 			{
 				VerifySuccessList.Add(verifyIno);

Assets/YooAsset/Runtime/CacheSystem/EVerifyResult.cs

@@ -9,7 +9,12 @@ namespace YooAsset
 		/// <summary>
 		/// 文件不存在
 		/// </summary>
-		FileNotExisted = -4,
+		FileNotExisted = -5,
+
+		/// <summary>
+		/// 文件移动失败（重命名失败）
+		/// </summary>
+		FileMoveFailed = -4,
 
 		/// <summary>
 		/// 文件内容不足（小于正常大小）

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

@@ -6,9 +6,12 @@ namespace YooAsset
 		protected enum ESteps
 		{
 			None,
-			CheckLocalFile,
+			CheckTempFile,
-			CreateDownload,
+			PrepareDownload,
+			CreateResumeDownloader,
+			CreateGeneralDownloader,
 			CheckDownload,
+			VerifyDownload,
 			TryAgain,
 			Succeed,
 			Failed,
@@ -56,7 +59,7 @@ namespace YooAsset
 			{
 				_failedTryAgain = failedTryAgain;
 				_timeout = timeout;
-				_steps = ESteps.CheckLocalFile;
+				_steps = ESteps.CheckTempFile;
 			}
 		}
 		public abstract void Update();

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

@@ -10,6 +10,7 @@ namespace YooAsset
 	internal sealed class FileDownloader : DownloaderBase
 	{
 		private readonly bool _breakResume;
+		private readonly string _tempFilePath;
 		private UnityWebRequest _webRequest = null;
 		private DownloadHandlerFileRange _downloadHandle = null;
 
@@ -24,6 +25,7 @@ namespace YooAsset
 		public FileDownloader(BundleInfo bundleInfo, bool breakResume) : base(bundleInfo)
 		{
 			_breakResume = breakResume;
+			_tempFilePath = bundleInfo.Bundle.CachedFilePath + ".temp";
 		}
 		public override void Update()
 		{
@@ -33,9 +35,9 @@ namespace YooAsset
 				return;
 
 			// 检测本地文件
-			if (_steps == ESteps.CheckLocalFile)
+			if (_steps == ESteps.CheckTempFile)
 			{
-				var verifyResult = CacheSystem.VerifyAndCacheBundle(_bundleInfo.Bundle, EVerifyLevel.High);
+				var verifyResult = CacheSystem.VerifyAndCacheDownloadBundleFile(_bundleInfo.Bundle, EVerifyLevel.High);
 				if (verifyResult == EVerifyResult.Succeed)
 				{
 					_steps = ESteps.Succeed;
@@ -44,19 +46,16 @@ namespace YooAsset
 				{
 					if (verifyResult == EVerifyResult.FileOverflow)
 					{
-						string cacheFilePath = _bundleInfo.Bundle.CachedFilePath;
+						if (File.Exists(_tempFilePath))
-						if (File.Exists(cacheFilePath))
+							File.Delete(_tempFilePath);
-							File.Delete(cacheFilePath);
 					}
-					_steps = ESteps.CreateDownload;
+					_steps = ESteps.PrepareDownload;
 				}
 			}
 
 			// 创建下载器
-			if (_steps == ESteps.CreateDownload)
+			if (_steps == ESteps.PrepareDownload)
 			{
-				string fileSavePath = _bundleInfo.Bundle.CachedFilePath;
-
 				// 重置变量
 				_downloadProgress = 0f;
 				_downloadedBytes = 0;
@@ -66,28 +65,28 @@ namespace YooAsset
 				_latestDownloadRealtime = Time.realtimeSinceStartup;
 				_tryAgainTimer = 0f;
 
-				// 是否开启断点续传下载	
+				// 获取请求地址
+				_requestURL = GetRequestURL();
+
 				if (_breakResume)
-				{
+					_steps = ESteps.CreateResumeDownloader;
-					long fileLength = -1;
+				else
-					if (File.Exists(fileSavePath))
+					_steps = ESteps.CreateGeneralDownloader;
-					{
-						FileInfo fileInfo = new FileInfo(fileSavePath);
-						fileLength = fileInfo.Length;
-						_fileOriginLength = (ulong)fileLength;
-						_downloadedBytes = _fileOriginLength;
 			}
 
-					_requestURL = GetRequestURL();
+			// 创建普通的下载器
-					_webRequest = UnityWebRequest.Get(_requestURL);
+			if (_steps == ESteps.CreateGeneralDownloader)
+			{
+				if (File.Exists(_tempFilePath))
+				{
+					File.Delete(_tempFilePath);
+				}
 
-#if UNITY_2019_4_OR_NEWER
+				_webRequest = new UnityWebRequest(_requestURL, UnityWebRequest.kHttpVerbGET);
-					var handler = new DownloadHandlerFile(fileSavePath, true);
+				DownloadHandlerFile handler = new DownloadHandlerFile(_tempFilePath);
-					handler.removeFileOnAbort = false;
+				handler.removeFileOnAbort = true;
-#else
+				_webRequest.downloadHandler = handler;
-					var handler = new DownloadHandlerFileRange(fileSavePath, _bundleInfo.Bundle.FileSize, _webRequest);
+				_webRequest.disposeDownloadHandlerOnDispose = true;
-					_downloadHandle = handler;
-#endif
 
 				if (DownloadSystem.CertificateHandlerInstance != null)
 				{
@@ -95,25 +94,45 @@ namespace YooAsset
 					_webRequest.disposeCertificateHandlerOnDispose = false;
 				}
 
+				_webRequest.SendWebRequest();
+				_steps = ESteps.CheckDownload;
+			}
+
+			// 创建断点续传下载器
+			if (_steps == ESteps.CreateResumeDownloader)
+			{
+				long fileLength = -1;
+				if (File.Exists(_tempFilePath))
+				{
+					FileInfo fileInfo = new FileInfo(_tempFilePath);
+					fileLength = fileInfo.Length;
+					_fileOriginLength = (ulong)fileLength;
+					_downloadedBytes = _fileOriginLength;
+				}
+
+#if UNITY_2019_4_OR_NEWER
+				_webRequest = new UnityWebRequest(_requestURL, UnityWebRequest.kHttpVerbGET);
+				var handler = new DownloadHandlerFile(_tempFilePath, true);
+				handler.removeFileOnAbort = false;
+#else
+				_webRequest = new UnityWebRequest(_requestURL, UnityWebRequest.kHttpVerbGET);
+				var handler = new DownloadHandlerFileRange(_tempFilePath, _bundleInfo.Bundle.FileSize, _webRequest);
+				_downloadHandle = handler;
+#endif
 				_webRequest.downloadHandler = handler;
 				_webRequest.disposeDownloadHandlerOnDispose = true;
 				if (fileLength > 0)
 					_webRequest.SetRequestHeader("Range", $"bytes={fileLength}-");
-					_webRequest.SendWebRequest();
+
-					_steps = ESteps.CheckDownload;
+				if (DownloadSystem.CertificateHandlerInstance != null)
-				}
-				else
 				{
-					_requestURL = GetRequestURL();
+					_webRequest.certificateHandler = DownloadSystem.CertificateHandlerInstance;
-					_webRequest = new UnityWebRequest(_requestURL, UnityWebRequest.kHttpVerbGET);
+					_webRequest.disposeCertificateHandlerOnDispose = false;
-					DownloadHandlerFile handler = new DownloadHandlerFile(fileSavePath);
+				}
-					handler.removeFileOnAbort = true;
+
-					_webRequest.downloadHandler = handler;
-					_webRequest.disposeDownloadHandlerOnDispose = true;
 				_webRequest.SendWebRequest();
 				_steps = ESteps.CheckDownload;
 			}
-			}
 
 			// 检测下载结果
 			if (_steps == ESteps.CheckDownload)
@@ -145,78 +164,77 @@ namespace YooAsset
 				}
 #endif
 
-				// 检查文件完整性
+				// 如果网络异常
-				if (hasError == false)
-				{
-					var verifyResult = CacheSystem.VerifyAndCacheBundle(_bundleInfo.Bundle, EVerifyLevel.High);
-					if (verifyResult != EVerifyResult.Succeed)
-					{
-						hasError = true;
-						_lastError = $"Verify bundle content failed : {_bundleInfo.Bundle.FileName}";
-						_lastCode = _webRequest.responseCode;
-
-						// 验证失败后删除文件
-						string cacheFilePath = _bundleInfo.Bundle.CachedFilePath;
-						if (File.Exists(cacheFilePath))
-							File.Delete(cacheFilePath);
-					}
-				}
-
-				// 如果下载失败
 				if (hasError)
 				{
-					// 注意：非断点续传下载失败之后删除文件
+					if (_breakResume)
-					if (_breakResume == false)
-					{
-						string cacheFilePath = _bundleInfo.Bundle.CachedFilePath;
-						if (File.Exists(cacheFilePath))
-							File.Delete(cacheFilePath);
-					}
-					else
 					{
 						// 注意：下载断点续传文件发生特殊错误码之后删除文件
 						if (DownloadSystem.ClearFileResponseCodes != null)
 						{
 							if (DownloadSystem.ClearFileResponseCodes.Contains(_webRequest.responseCode))
 							{
-								string cacheFilePath = _bundleInfo.Bundle.CachedFilePath;
+								if (File.Exists(_tempFilePath))
-								if (File.Exists(cacheFilePath))
+									File.Delete(_tempFilePath);
-									File.Delete(cacheFilePath);
 							}
 						}
 					}
+					else
+					{
+						// 注意：非断点续传下载失败之后删除文件
+						if (File.Exists(_tempFilePath))
+							File.Delete(_tempFilePath);
+					}
 
-					// 失败后重新尝试
-					if (_failedTryAgain > 0)
-					{
-						ReportWarning();
 					_steps = ESteps.TryAgain;
 				}
 				else
 				{
-						ReportError();
+					_steps = ESteps.VerifyDownload;
-						_steps = ESteps.Failed;
-					}
-				}
-				else
-				{
-					_lastError = string.Empty;
-					_lastCode = 0;
-					_steps = ESteps.Succeed;
 				}
 
 				// 释放下载器
 				DisposeWebRequest();
 			}
 
+			// 验证下载文件
+			if (_steps == ESteps.VerifyDownload)
+			{
+				var verifyResult = CacheSystem.VerifyAndCacheDownloadBundleFile(_bundleInfo.Bundle, EVerifyLevel.High);
+				if (verifyResult == EVerifyResult.Succeed)
+				{
+					_lastError = string.Empty;
+					_lastCode = 0;
+					_steps = ESteps.Succeed;
+				}
+				else
+				{
+					_lastError = $"Verify bundle content failed : {_bundleInfo.Bundle.FileName}";
+
+					// 验证失败后删除文件
+					if (File.Exists(_tempFilePath))
+						File.Delete(_tempFilePath);
+
+					_steps = ESteps.TryAgain;
+				}
+			}
+
 			// 重新尝试下载
 			if (_steps == ESteps.TryAgain)
 			{
+				if (_failedTryAgain <= 0)
+				{
+					ReportError();
+					_steps = ESteps.Failed;
+					return;
+				}
+
 				_tryAgainTimer += Time.unscaledDeltaTime;
 				if (_tryAgainTimer > 1f)
 				{
 					_failedTryAgain--;
-					_steps = ESteps.CreateDownload;
+					_steps = ESteps.PrepareDownload;
+					ReportWarning();
 					YooLogger.Warning($"Try again download : {_requestURL}");
 				}
 			}