From 39dc55bac314a50613c49deffd389e997764d54b Mon Sep 17 00:00:00 2001
From: shawnnqin <shawnnqin@tencent.com>
Date: Mon, 29 Nov 2021 21:31:36 +0800
Subject: [PATCH] bug fix

---
 .../COSXML/Network/ResponseBody.cs            | 13 ++++-
 QCloudCSharpSDK/COSXMLTests/ObjectTest.cs     | 50 +++++++++++++------
 2 files changed, 47 insertions(+), 16 deletions(-)

diff --git a/QCloudCSharpSDK/COSXML/Network/ResponseBody.cs b/QCloudCSharpSDK/COSXML/Network/ResponseBody.cs
index b3b3281..4f5bf9e 100644
--- a/QCloudCSharpSDK/COSXML/Network/ResponseBody.cs
+++ b/QCloudCSharpSDK/COSXML/Network/ResponseBody.cs
@@ -92,7 +92,7 @@ public void HandleResponseBody(Stream inputStream)
                 {
                     if (File.Exists(filePath) && new FileInfo(filePath).Length > fileOffset)
                     {
-                        // 写脏文件了，直接Truncate掉
+                        // 写脏文件了，直接 Truncate
                         fileStream = new FileStream(filePath, FileMode.Truncate, FileAccess.Write);
                     }
                     else 
@@ -190,7 +190,16 @@ public void StartHandleResponseBody(Stream inputStream, EndResponseBody endRespo
 
                 if (isDownload)
                 {
-                    fileStream = new FileStream(filePath, FileMode.OpenOrCreate, FileAccess.Write);
+                    if (File.Exists(filePath) && new FileInfo(filePath).Length > fileOffset)
+                    {
+                        // 写脏文件了，直接 Truncate
+                        fileStream = new FileStream(filePath, FileMode.Truncate, FileAccess.Write);
+                    }
+                    else 
+                    {
+                        // 正常文件或者追加写场景，直接写入
+                        fileStream = new FileStream(filePath, FileMode.OpenOrCreate, FileAccess.Write);
+                    }
                     fileStream.Seek(fileOffset, SeekOrigin.Begin);
                     responseBodyState.inputStream.BeginRead(responseBodyState.buffer, 0, responseBodyState.buffer.Length, AsyncStreamCallback, responseBodyState);
                 }
diff --git a/QCloudCSharpSDK/COSXMLTests/ObjectTest.cs b/QCloudCSharpSDK/COSXMLTests/ObjectTest.cs
index d3f7876..bf668d3 100644
--- a/QCloudCSharpSDK/COSXMLTests/ObjectTest.cs
+++ b/QCloudCSharpSDK/COSXMLTests/ObjectTest.cs
@@ -1507,21 +1507,43 @@ public void TestDownloadTaskCancelled()
         [Test()]
         public void TestDownloadTaskOverwriteSameFile()
         {
+            try {
+                GetObjectRequest request = new GetObjectRequest(bucket, multiKey, localDir, localFileName);
+                
+                COSXMLDownloadTask downloadTask = new COSXMLDownloadTask(request);
+                var asyncTask = transferManager.DownloadAsync(downloadTask);
+                asyncTask.Wait();
+                
+                //GetObjectResult result = cosXml.GetObject(request);
+                //Assert.AreEqual(200, result.httpCode);
+                long bigLength = new FileInfo(localFileName).Length;
+                // 再下载一个小文件
+                // 存在一致性问题，把小文件重新上传一下
+                PutObject();
+                request = new GetObjectRequest(bucket, commonKey, localDir, localFileName);
+                
+                downloadTask = new COSXMLDownloadTask(request);
+                asyncTask = transferManager.DownloadAsync(downloadTask);
+                asyncTask.Wait();
+                
+                //result = cosXml.GetObject(request);
+                //Assert.AreEqual(200, result.httpCode);
+                // 检查文件长度，是否覆盖写
+                long smallLength = new FileInfo(localFileName).Length;
+                
+                Assert.True(smallLength < bigLength);
+            }
+            catch (COSXML.CosException.CosClientException clientEx)
+            {
+                Console.WriteLine("CosClientException: " + clientEx.Message);
+                Assert.Fail();
+            }
+            catch (COSXML.CosException.CosServerException serverEx)
+            {
+                Console.WriteLine("CosServerException: " + serverEx.GetInfo());
+                Assert.Fail();
+            }
             // 先下载一个大文件
-            GetObjectRequest request = new GetObjectRequest(bucket, multiKey, localDir, localFileName);
-            COSXMLDownloadTask downloadTask = new COSXMLDownloadTask(request);
-            var asyncTask = transferManager.DownloadAsync(downloadTask);
-            asyncTask.Wait();
-            long bigLength = new FileInfo(localFileName).Length;
-            // 再下载一个小文件
-            request = new GetObjectRequest(bucket, commonKey, localDir, localFileName);
-            downloadTask = new COSXMLDownloadTask(request);
-            asyncTask = transferManager.DownloadAsync(downloadTask);
-            asyncTask.Wait();
-
-            // 检查文件长度，是否覆盖写
-            long smallLength = new FileInfo(localFileName).Length;
-            Assert.True(smallLength < bigLength);
         }
 
         [Test()]