Merge pull request #172 from mono/opt-out-alc

Add host option to disable AssemblyLoadContext

Mono.TextTemplating/Mono.TextTemplating.CodeCompilation/CompiledAssemblyData.cs

@@ -38,7 +38,7 @@ public Assembly LoadInAssemblyLoadContext (AssemblyLoadContext loadContext)
  return loadContext.LoadFromStream (new MemoryStream (Assembly));
  }
  }
-#else
+#endif
  public Assembly LoadInCurrentAppDomain ()
  {
  if (DebugSymbols != null) {
@@ -47,6 +47,5 @@ public Assembly LoadInCurrentAppDomain ()
  return System.Reflection.Assembly.Load (Assembly);
  }
  }
-#endif
  }
 }

Mono.TextTemplating/Mono.TextTemplating/CompiledTemplate.TemplateAssemblyContext.cs

@@ -11,21 +11,51 @@ namespace Mono.TextTemplating;
 
 partial class CompiledTemplate
 {
- [SuppressMessage ("Performance", "CA1822:Mark members as static", Justification = "Same API for ALC and AppDomain build variants of the class")]
- sealed class TemplateAssemblyContext : IDisposable
+ /// <summary>
+ /// Abstracts over loading assemblies into an AssemblyLoadContext or AppDomain
+ /// and resolving assemblies from the host.
+ /// </summary>
+ abstract class TemplateAssemblyContext : IDisposable
  {
+ public abstract Assembly LoadAssemblyFile (string assemblyPath);
+ public abstract Assembly LoadInMemoryAssembly (CompiledAssemblyData assemblyData);
+ public virtual void Dispose () { }
+
+ [SuppressMessage ("Performance", "CA1859:Use concrete types when possible for improved performance", Justification = "Conditionally compiled version of this returns multiple concrete types")]
+
+ public static TemplateAssemblyContext Create (ITextTemplatingEngineHost host, string[] referenceAssemblyFiles)
+ {
+#if FEATURE_ASSEMBLY_LOAD_CONTEXT
+ if (!host.IsAssemblyLoadContextDisabled ()) {
+ return new AssemblyLoadContextTemplateAssemblyContext (host, referenceAssemblyFiles);
+ }
+#endif
+ return new CurrentAppDomainTemplateAssemblyContext (host, referenceAssemblyFiles);
+ }
+ }
+
 #if FEATURE_ASSEMBLY_LOAD_CONTEXT
+ sealed class AssemblyLoadContextTemplateAssemblyContext : TemplateAssemblyContext
+ {
  readonly TemplateAssemblyLoadContext templateContext;
- public TemplateAssemblyContext (ITextTemplatingEngineHost host, string[] referenceAssemblyFiles) => templateContext = new (referenceAssemblyFiles, host);
- public Assembly LoadAssemblyFile (string assemblyPath) => templateContext.LoadFromAssemblyPath (assemblyPath);
- public Assembly LoadInMemoryAssembly (CompiledAssemblyData assemblyData) => assemblyData.LoadInAssemblyLoadContext (templateContext);
- public void Dispose () { }
-#else
- readonly CurrentDomainAssemblyResolver assemblyResolver;
- public TemplateAssemblyContext (ITextTemplatingEngineHost host, string[] referenceAssemblyFiles) => assemblyResolver = new (referenceAssemblyFiles, host.ResolveAssemblyReference);
- public Assembly LoadAssemblyFile (string assemblyPath) => Assembly.LoadFile (assemblyPath);
- public Assembly LoadInMemoryAssembly (CompiledAssemblyData assemblyData) => assemblyData.LoadInCurrentAppDomain ();
- public void Dispose () => assemblyResolver.Dispose ();
+ public AssemblyLoadContextTemplateAssemblyContext (ITextTemplatingEngineHost host, string[] referenceAssemblyFiles)
+ => templateContext = new (referenceAssemblyFiles, host);
+ public override Assembly LoadAssemblyFile (string assemblyPath) => templateContext.LoadFromAssemblyPath (assemblyPath);
+ public override Assembly LoadInMemoryAssembly (CompiledAssemblyData assemblyData) => assemblyData.LoadInAssemblyLoadContext (templateContext);
+ }
 #endif
+
+ sealed class CurrentAppDomainTemplateAssemblyContext : TemplateAssemblyContext
+ {
+ readonly CurrentDomainAssemblyResolver assemblyResolver;
+ public CurrentAppDomainTemplateAssemblyContext (ITextTemplatingEngineHost host, string[] referenceAssemblyFiles)
+ => assemblyResolver = new (referenceAssemblyFiles, host.ResolveAssemblyReference);
+ public override Assembly LoadAssemblyFile (string assemblyPath) => Assembly.LoadFile (assemblyPath);
+ public override Assembly LoadInMemoryAssembly (CompiledAssemblyData assemblyData) => assemblyData.LoadInCurrentAppDomain ();
+ public override void Dispose ()
+ {
+ base.Dispose ();
+ assemblyResolver.Dispose ();
+ }
  }
 }

Mono.TextTemplating/Mono.TextTemplating/CompiledTemplate.TemplateExecutor.cs

@@ -19,7 +19,7 @@ class TemplateProcessor : MarshalByRefObject
  [SuppressMessage ("Performance", "CA1822:Mark members as static", Justification = "Needs to be an instance for MarshalByRefObject")]
  public string CreateAndProcess (ITextTemplatingEngineHost host, CompiledAssemblyData templateAssemblyData, string templateAssemblyFile, string fullName, CultureInfo culture, string[] referencedAssemblyFiles)
  {
- using var context = new TemplateAssemblyContext (host, referencedAssemblyFiles);
+ using var context = TemplateAssemblyContext.Create (host, referencedAssemblyFiles);
 
  Assembly assembly = templateAssemblyData is not null
  ? context.LoadInMemoryAssembly (templateAssemblyData)

Mono.TextTemplating/Mono.TextTemplating/CurrentDomainAssemblyResolver.cs

@@ -1,8 +1,6 @@
 // Copyright (c) Microsoft. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
-#if !FEATURE_ASSEMBLY_LOAD_CONTEXT
-
 using System;
 using System.IO;
 using System.Reflection;
@@ -52,5 +50,3 @@ public void Dispose ()
  }
  }
 }
-
-#endif

Mono.TextTemplating/Mono.TextTemplating/HostOptions.cs

@@ -0,0 +1,16 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System;
+using Microsoft.VisualStudio.TextTemplating;
+
+static class HostOptionExtensions
+{
+ const string DisableAlcOptionName = "DisableAssemblyLoadContext";
+
+ static bool IsOptionTrue (this ITextTemplatingEngineHost host, string optionName) =>
+ host.GetHostOption(optionName) is string optionVal
+ && (optionVal == "1" || optionVal.Equals("true", StringComparison.OrdinalIgnoreCase));
+
+ public static bool IsAssemblyLoadContextDisabled (this ITextTemplatingEngineHost host) => host.IsOptionTrue (DisableAlcOptionName);
+}