From a240d61e0e056d6bda118936f4ff16c5d2e6de36 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Manuel=20Le=C3=9Fmann?= <mlessmann@users.noreply.github.com>
Date: Mon, 18 Sep 2023 14:23:50 +0200
Subject: [PATCH] feat: Load exported assembly in separated AssemblyLoadContext
 (#192)
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* Load exported assembly in separated AssemblyLoadContext

* Fix warning

---------

Co-authored-by: Manuel Leßmann <MLessmann@dspace.de>
---
 src/dscom.client/AssemblyResolver.cs | 44 ++++++++++++++++++----------
 src/dscom.client/Program.cs          |  9 +++---
 2 files changed, 33 insertions(+), 20 deletions(-)

diff --git a/src/dscom.client/AssemblyResolver.cs b/src/dscom.client/AssemblyResolver.cs
index 6c53ab7..0b0a50b 100644
--- a/src/dscom.client/AssemblyResolver.cs
+++ b/src/dscom.client/AssemblyResolver.cs
@@ -1,11 +1,11 @@
 // Copyright 2022 dSPACE GmbH, Mark Lechtermann, Matthias Nissen and Contributors
-// 
+//
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
-// 
+//
 //     http://www.apache.org/licenses/LICENSE-2.0
-// 
+//
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -13,6 +13,7 @@
 // limitations under the License.
 
 using System.Reflection;
+using System.Runtime.Loader;
 
 namespace dSPACE.Runtime.InteropServices;
 
@@ -21,46 +22,59 @@ namespace dSPACE.Runtime.InteropServices;
 /// </summary>
 internal sealed class AssemblyResolver : IDisposable
 {
+    private readonly AssemblyLoadContext _context;
     private bool _disposedValue;
 
     internal AssemblyResolver(TypeLibConverterOptions options)
     {
         Options = options;
-        AppDomain.CurrentDomain.AssemblyResolve += ResolveEventHandler;
+        _context = new AssemblyLoadContext("dscom", true);
+        _context.Resolving += Context_Resolving;
     }
 
-    public TypeLibConverterOptions Options { get; }
-
-    private Assembly? ResolveEventHandler(object? sender, ResolveEventArgs args)
+    private Assembly? Context_Resolving(AssemblyLoadContext context, AssemblyName name)
     {
-        var name = args.Name;
-        var fileNameWithoutExtension = new AssemblyName(name).Name;
+        var dir = Path.GetDirectoryName(Options.Assembly);
+
+        var asmPaths = Options.ASMPath;
+        if (Directory.Exists(dir))
+        {
+            asmPaths = asmPaths.Prepend(dir).ToArray();
+        }
 
-        foreach (var path in Options.ASMPath)
+        foreach (var path in asmPaths)
         {
-            var dllToLoad = Path.Combine(path, $"{fileNameWithoutExtension}.dll");
+            var dllToLoad = Path.Combine(path, $"{name.Name}.dll");
             if (File.Exists(dllToLoad))
             {
-                return Assembly.LoadFrom(dllToLoad);
+                return _context.LoadFromAssemblyPath(dllToLoad);
             }
 
-            var exeToLoad = Path.Combine(path, $"{fileNameWithoutExtension}.exe");
+            var exeToLoad = Path.Combine(path, $"{name.Name}.exe");
             if (File.Exists(exeToLoad))
             {
-                return Assembly.LoadFrom(exeToLoad);
+                return _context.LoadFromAssemblyPath(exeToLoad);
             }
         }
 
         return null;
     }
 
+    public Assembly LoadAssembly(string path)
+    {
+        return _context.LoadFromAssemblyPath(path);
+    }
+
+    public TypeLibConverterOptions Options { get; }
+
     private void Dispose(bool disposing)
     {
         if (!_disposedValue)
         {
             if (disposing)
             {
-                AppDomain.CurrentDomain.ReflectionOnlyAssemblyResolve -= ResolveEventHandler;
+                _context.Resolving -= Context_Resolving;
+                _context.Unload();
             }
 
             _disposedValue = true;
diff --git a/src/dscom.client/Program.cs b/src/dscom.client/Program.cs
index 5710d20..7b5ec88 100644
--- a/src/dscom.client/Program.cs
+++ b/src/dscom.client/Program.cs
@@ -1,11 +1,11 @@
 // Copyright 2022 dSPACE GmbH, Mark Lechtermann, Matthias Nissen and Contributors
-// 
+//
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
-// 
+//
 //     http://www.apache.org/licenses/LICENSE-2.0
-// 
+//
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -16,7 +16,6 @@
 using System.CommandLine.NamingConventionBinder;
 using System.CommandLine.Parsing;
 using System.Diagnostics;
-using System.Reflection;
 using System.Runtime.InteropServices;
 
 namespace dSPACE.Runtime.InteropServices;
@@ -161,7 +160,7 @@ private static void ConfigureTLBExportHandler(Command tlbexportCommand)
                     throw new FileNotFoundException($"File {options.Assembly} not found.");
                 }
 
-                var assembly = Assembly.LoadFrom(options.Assembly);
+                var assembly = assemblyResolver.LoadAssembly(options.Assembly);
                 var typeLibConverter = new TypeLibConverter();
                 var nameResolver = options.Names.Any() ? NameResolver.Create(options.Names) : NameResolver.Create(assembly);
                 var typeLib = typeLibConverter.ConvertAssemblyToTypeLib(assembly, options, new TypeLibExporterNotifySink(options, nameResolver));