Fix AR and PE output stream flushing

Author: xoofx

src/LibObjectFile.Tests/Ar/ArTests.cs

@@ -313,6 +313,22 @@ public void CheckLibraryWithELF()
         }
     }
 
+    [TestMethod]
+    public void TestWriteFlushesOutputStream()
+    {
+        var archive = new ArArchiveFile();
+        archive.AddFile(new ArBinaryFile
+        {
+            Name = "file.txt",
+            Stream = new MemoryStream(Encoding.UTF8.GetBytes("content"))
+        });
+        using var output = new FlushTrackingStream();
+
+        archive.Write(output);
+
+        Assert.IsTrue(output.WasFlushed);
+    }
+
     [TestMethod]
     public async Task CheckCreateArLibrary()
     {
@@ -427,4 +443,4 @@ private static void CompareArFiles(ArArchiveFile archiveFile, ArArchiveFile file
             }
         }
     }
-}
+}

src/LibObjectFile.Tests/Elf/ElfSimpleTests.cs

@@ -673,15 +673,4 @@ public async Task TestElf(string name)
     {
         await LoadAndVerifyElf(name);
     }
-
-    private sealed class FlushTrackingStream : MemoryStream
-    {
-        public bool WasFlushed { get; private set; }
-
-        public override void Flush()
-        {
-            WasFlushed = true;
-            base.Flush();
-        }
-    }
 }

src/LibObjectFile.Tests/FlushTrackingStream.cs

@@ -0,0 +1,18 @@
+// Copyright (c) Alexandre Mutel. All rights reserved.
+// This file is licensed under the BSD-Clause 2 license.
+// See the license.txt file in the project root for more information.
+
+using System.IO;
+
+namespace LibObjectFile.Tests;
+
+internal sealed class FlushTrackingStream : MemoryStream
+{
+    public bool WasFlushed { get; private set; }
+
+    public override void Flush()
+    {
+        WasFlushed = true;
+        base.Flush();
+    }
+}

src/LibObjectFile.Tests/PE/PEReaderTests.cs

@@ -181,6 +181,17 @@ public void TestReadShortDosStub()
         Assert.AreEqual(56, readPE.DosStub.Length);
     }
 
+    [TestMethod]
+    public void TestWriteFlushesOutputStream()
+    {
+        var pe = new PEFile();
+        using var output = new FlushTrackingStream();
+
+        pe.Write(output);
+
+        Assert.IsTrue(output.WasFlushed);
+    }
+
     [TestMethod]
     public void TestPrinterUsesStableDateFormat()
     {

src/LibObjectFile/Ar/ArArchiveFile.cs

@@ -318,11 +318,13 @@ public static bool TryRead(Stream stream, ArArchiveFileReaderOptions options, ou
     /// Writes this 'ar' archive file to the specified stream.
     /// </summary>
     /// <param name="stream">The stream to write to.</param>
+    /// <remarks>The stream is flushed before this method returns but is not disposed.</remarks>
     public void Write(Stream stream)
     {
         if (stream == null) throw new ArgumentNullException(nameof(stream));
         var writer = new ArArchiveFileWriter(this, stream);
         writer.Write();
+        stream.Flush();
     }
 
     protected override void UpdateLayoutCore(ArVisitorContext context)
@@ -400,4 +402,4 @@ public void UpdateLayout(DiagnosticBag diagnostics)
 
         Size = size;
     }
-}
+}

src/LibObjectFile/PE/PEFile.Write.cs

@@ -21,6 +21,7 @@ partial class PEFile
     /// Writes this PE file to the specified stream.
     /// </summary>
     /// <param name="stream">The stream to write to.</param>
+    /// <remarks>The stream is flushed before this method returns but is not disposed.</remarks>
     public void Write(Stream stream, PEImageWriterOptions? options = null)
     {
         if (!TryWrite(stream, out var diagnostics, options))
@@ -35,6 +36,7 @@ public void Write(Stream stream, PEImageWriterOptions? options = null)
     /// <param name="stream">The stream to write to.</param>
     /// <param name="diagnostics">The output diagnostics</param>
     /// <returns><c>true</c> if writing was successful. otherwise <c>false</c></returns>
+    /// <remarks>The stream is flushed after a successful write but is not disposed.</remarks>
     public bool TryWrite(Stream stream, out DiagnosticBag diagnostics, PEImageWriterOptions? options = null)
     {
         if (stream == null) throw new ArgumentNullException(nameof(stream));
@@ -67,6 +69,7 @@ public bool TryWrite(Stream stream, out DiagnosticBag diagnostics, PEImageWriter
 
         // Write the PE file
         Write(peWriter);
+        stream.Flush();
 
         return !diagnostics.HasErrors;
     }