From 08002efea277e3bfe36e6c8bd51f8eb8391290ae Mon Sep 17 00:00:00 2001
From: Spike Curtis <spike@coder.com>
Date: Tue, 29 Apr 2025 15:45:17 +0400
Subject: [PATCH 1/2] fix: fix Downloader to always dispose of temp file stream

---
 Vpn.Service/Downloader.cs | 27 +++++++++++++--------------
 1 file changed, 13 insertions(+), 14 deletions(-)

diff --git a/Vpn.Service/Downloader.cs b/Vpn.Service/Downloader.cs
index 467c9af..4ad826c 100644
--- a/Vpn.Service/Downloader.cs
+++ b/Vpn.Service/Downloader.cs
@@ -453,27 +453,26 @@ private async Task Start(CancellationToken ct = default)
         if (res.Content.Headers.ContentLength >= 0)
             TotalBytes = (ulong)res.Content.Headers.ContentLength;
 
-        FileStream tempFile;
-        try
-        {
-            tempFile = File.Create(TempDestinationPath, BufferSize,
-                FileOptions.Asynchronous | FileOptions.SequentialScan);
-        }
-        catch (Exception e)
-        {
-            _logger.LogError(e, "Failed to create temporary file '{TempDestinationPath}'", TempDestinationPath);
-            throw;
-        }
-
-        await Download(res, tempFile, ct);
+        await Download(res, ct);
         return;
     }
 
-    private async Task Download(HttpResponseMessage res, FileStream tempFile, CancellationToken ct)
+    private async Task Download(HttpResponseMessage res, CancellationToken ct)
     {
         try
         {
             var sha1 = res.Headers.Contains("ETag") ? SHA1.Create() : null;
+            FileStream tempFile;
+            try
+            {
+                tempFile = File.Create(TempDestinationPath, BufferSize,
+                    FileOptions.Asynchronous | FileOptions.SequentialScan);
+            }
+            catch (Exception e)
+            {
+                _logger.LogError(e, "Failed to create temporary file '{TempDestinationPath}'", TempDestinationPath);
+                throw;
+            }
             await using (tempFile)
             {
                 var stream = await res.Content.ReadAsStreamAsync(ct);

From 31b43f6af3ac8baf26cd109d09cd58490a2405ed Mon Sep 17 00:00:00 2001
From: Spike Curtis <spike@coder.com>
Date: Wed, 30 Apr 2025 10:18:06 +0400
Subject: [PATCH 2/2] chore: change temp file I/O to not overlap

---
 Tests.Vpn.Service/DownloaderTest.cs | 17 +++++++++++------
 Vpn.Service/Downloader.cs           |  3 +--
 2 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/Tests.Vpn.Service/DownloaderTest.cs b/Tests.Vpn.Service/DownloaderTest.cs
index b30e3e4..986ce46 100644
--- a/Tests.Vpn.Service/DownloaderTest.cs
+++ b/Tests.Vpn.Service/DownloaderTest.cs
@@ -442,23 +442,28 @@ public async Task CancelledWaitingForOther(CancellationToken ct)
     [CancelAfter(30_000)]
     public async Task CancelledInner(CancellationToken ct)
     {
+        var httpCts = CancellationTokenSource.CreateLinkedTokenSource(ct);
+        var taskCts = CancellationTokenSource.CreateLinkedTokenSource(ct);
         using var httpServer = new TestHttpServer(async ctx =>
         {
             ctx.Response.StatusCode = 200;
-            await ctx.Response.OutputStream.WriteAsync("test"u8.ToArray(), ct);
-            await ctx.Response.OutputStream.FlushAsync(ct);
-            await Task.Delay(TimeSpan.FromSeconds(5), ct);
+            await ctx.Response.OutputStream.WriteAsync("test"u8.ToArray(), httpCts.Token);
+            await ctx.Response.OutputStream.FlushAsync(httpCts.Token);
+            // wait up to 5 seconds.
+            await Task.Delay(TimeSpan.FromSeconds(5), httpCts.Token);
         });
         var url = new Uri(httpServer.BaseUrl + "/test");
         var destPath = Path.Combine(_tempDir, "test");
 
         var manager = new Downloader(NullLogger<Downloader>.Instance);
         // The "inner" Task should fail.
-        var smallerCt = new CancellationTokenSource(TimeSpan.FromSeconds(1)).Token;
+        var taskCt = taskCts.Token;
         var dlTask = await manager.StartDownloadAsync(new HttpRequestMessage(HttpMethod.Get, url), destPath,
-            NullDownloadValidator.Instance, smallerCt);
+            NullDownloadValidator.Instance, taskCt);
+        await taskCts.CancelAsync();
         var ex = Assert.ThrowsAsync<TaskCanceledException>(async () => await dlTask.Task);
-        Assert.That(ex.CancellationToken, Is.EqualTo(smallerCt));
+        Assert.That(ex.CancellationToken, Is.EqualTo(taskCt));
+        await httpCts.CancelAsync();
     }
 
     [Test(Description = "Validation failure")]
diff --git a/Vpn.Service/Downloader.cs b/Vpn.Service/Downloader.cs
index 4ad826c..c7b94c6 100644
--- a/Vpn.Service/Downloader.cs
+++ b/Vpn.Service/Downloader.cs
@@ -465,8 +465,7 @@ private async Task Download(HttpResponseMessage res, CancellationToken ct)
             FileStream tempFile;
             try
             {
-                tempFile = File.Create(TempDestinationPath, BufferSize,
-                    FileOptions.Asynchronous | FileOptions.SequentialScan);
+                tempFile = File.Create(TempDestinationPath, BufferSize, FileOptions.SequentialScan);
             }
             catch (Exception e)
             {