Enable PersistentProxyBuilder on .NET 9+ (albeit without type cache)

Author: stakx

src/Castle.Core/DynamicProxy/DefaultProxyBuilder.cs

@@ -20,6 +20,11 @@ namespace Castle.DynamicProxy
 	using System.Collections.Generic;
 	using System.Linq;
 	using System.Reflection;
+#if NET9_0_OR_GREATER
+	using System.IO;
+	using System.Reflection.Emit;
+	using System.Runtime.Loader;
+#endif
 
 	using Castle.Core.Internal;
 	using Castle.Core.Logging;
@@ -30,9 +35,14 @@ namespace Castle.DynamicProxy
 	/// </summary>
 	public class DefaultProxyBuilder : IProxyBuilder
 	{
-		private readonly ModuleScope scope;
+		private ModuleScope scope;
 		private ILogger logger = NullLogger.Instance;
 
+#if NET9_0_OR_GREATER
+		protected ModuleScope lastScope;
+		protected MemoryStream lastAssemblyGenerated;
+#endif
+
 		/// <summary>
 		///   Initializes a new instance of the <see cref = "DefaultProxyBuilder" /> class with new <see cref = "ModuleScope" />.
 		/// </summary>
@@ -68,7 +78,7 @@ public Type CreateClassProxyType(Type classToProxy, Type[]? additionalInterfaces
 			AssertValidMixins(options, nameof(options));
 
 			var generator = new ClassProxyGenerator(scope, classToProxy, additionalInterfacesToProxy, options) { Logger = logger };
-			return generator.GetProxyType();
+			return ToInstantiableType(generator.GetProxyType(), generator);
 		}
 
 		public Type CreateClassProxyTypeWithTarget(Type classToProxy, Type[]? additionalInterfacesToProxy,
@@ -80,7 +90,7 @@ public Type CreateClassProxyTypeWithTarget(Type classToProxy, Type[]? additional
 
 			var generator = new ClassProxyWithTargetGenerator(scope, classToProxy, additionalInterfacesToProxy, options)
 			{ Logger = logger };
-			return generator.GetProxyType();
+			return ToInstantiableType(generator.GetProxyType(), generator);
 		}
 
 		public Type CreateInterfaceProxyTypeWithTarget(Type interfaceToProxy, Type[]? additionalInterfacesToProxy,
@@ -92,7 +102,7 @@ public Type CreateInterfaceProxyTypeWithTarget(Type interfaceToProxy, Type[]? ad
 			AssertValidMixins(options, nameof(options));
 
 			var generator = new InterfaceProxyWithTargetGenerator(scope, interfaceToProxy, additionalInterfacesToProxy, targetType, options) { Logger = logger };
-			return generator.GetProxyType();
+			return ToInstantiableType(generator.GetProxyType(), generator);
 		}
 
 		public Type CreateInterfaceProxyTypeWithTargetInterface(Type interfaceToProxy, Type[]? additionalInterfacesToProxy,
@@ -103,7 +113,7 @@ public Type CreateInterfaceProxyTypeWithTargetInterface(Type interfaceToProxy, T
 			AssertValidMixins(options, nameof(options));
 
 			var generator = new InterfaceProxyWithTargetInterfaceGenerator(scope, interfaceToProxy, additionalInterfacesToProxy, interfaceToProxy, options) { Logger = logger };
-			return generator.GetProxyType();
+			return ToInstantiableType(generator.GetProxyType(), generator);
 		}
 
 		public Type CreateInterfaceProxyTypeWithoutTarget(Type interfaceToProxy, Type[]? additionalInterfacesToProxy,
@@ -114,7 +124,28 @@ public Type CreateInterfaceProxyTypeWithoutTarget(Type interfaceToProxy, Type[]?
 			AssertValidMixins(options, nameof(options));
 
 			var generator = new InterfaceProxyWithoutTargetGenerator(scope, interfaceToProxy, additionalInterfacesToProxy, typeof(object), options) { Logger = logger };
-			return generator.GetProxyType();
+			return ToInstantiableType(generator.GetProxyType(), generator);
+		}
+
+		private Type ToInstantiableType(Type type, BaseProxyGenerator generator)
+		{
+#if NET9_0_OR_GREATER
+			if (type.Assembly is PersistedAssemblyBuilder persistedAssemblyBuilder)
+			{
+				lastAssemblyGenerated?.Dispose();
+				var stream = new MemoryStream();
+				persistedAssemblyBuilder.Save(stream);
+				stream.Seek(0, SeekOrigin.Begin);
+				var assembly = AssemblyLoadContext.Default.LoadFromStream(stream);
+				type = assembly.GetType(type.FullName!)!;
+				lastAssemblyGenerated = stream;
+				lastScope = scope;
+				scope = scope.Recycle();
+			}
+
+			generator.InitializeStaticFields(type);
+#endif
+			return type;
 		}
 
 		private void AssertValidMixins(ProxyGenerationOptions options, string paramName)

src/Castle.Core/DynamicProxy/Generators/BaseClassProxyGenerator.cs

@@ -102,7 +102,9 @@ protected sealed override Type GenerateType(string name, INamingScope namingScop
 			// Crosses fingers and build type
 
 			var proxyType = emitter.BuildType();
+#if !NET9_0_OR_GREATER
 			InitializeStaticFields(proxyType);
+#endif
 			return proxyType;
 		}
 

src/Castle.Core/DynamicProxy/Generators/BaseInterfaceProxyGenerator.cs

@@ -137,8 +137,9 @@ protected override Type GenerateType(string typeName, INamingScope namingScope)
 
 			// Crosses fingers and build type
 			var generatedType = emitter.BuildType();
-
+#if !NET9_0_OR_GREATER
 			InitializeStaticFields(generatedType);
+#endif
 			return generatedType;
 		}
 

src/Castle.Core/DynamicProxy/Generators/BaseProxyGenerator.cs

@@ -384,7 +384,7 @@ protected void HandleExplicitlyPassedProxyTargetAccessor(ICollection<Type> targe
 			}
 		}
 
-		protected void InitializeStaticFields(Type builtType)
+		internal void InitializeStaticFields(Type builtType)
 		{
 			builtType.SetStaticField("proxyGenerationOptions", BindingFlags.NonPublic, ProxyGenerationOptions);
 		}

src/Castle.Core/DynamicProxy/ModuleScope.cs

@@ -150,6 +150,13 @@ internal INamingScope NamingScope
 
 		internal SynchronizedDictionary<CacheKey, Type> TypeCache => typeCache;
 
+#if NET9_0_OR_GREATER
+		internal ModuleScope Recycle()
+		{
+			return new ModuleScope(savePhysicalAssembly, disableSignedModule, strongAssemblyName, strongModulePath, weakAssemblyName, weakModulePath);
+		}
+#endif
+
 		/// <summary>
 		///   Gets the key pair used to sign the strong-named assembly generated by this <see cref = "ModuleScope" />.
 		/// </summary>
@@ -336,6 +343,14 @@ private ModuleBuilder CreateModule(bool signStrongName)
 				return module;
 			}
 			else
+#elif NET9_0_OR_GREATER
+			if (savePhysicalAssembly)
+			{
+				AssemblyBuilder assemblyBuilder = new PersistedAssemblyBuilder(assemblyName, typeof(object).Assembly);
+				var module = assemblyBuilder.DefineDynamicModule(moduleName);
+				return module;
+			}
+			else
 #endif
 			{
 #if FEATURE_APPDOMAIN
@@ -368,7 +383,7 @@ private AssemblyName GetAssemblyName(bool signStrongName)
 			return assemblyName;
 		}
 
-#if FEATURE_ASSEMBLYBUILDER_SAVE
+#if FEATURE_ASSEMBLYBUILDER_SAVE || NET9_0_OR_GREATER
 		/// <summary>
 		///   Saves the generated assembly with the name and directory information given when this <see cref = "ModuleScope" /> instance was created (or with
 		///   the <see cref = "DEFAULT_FILE_NAME" /> and current directory if none was given).
@@ -450,7 +465,11 @@ private AssemblyName GetAssemblyName(bool signStrongName)
 				}
 				assemblyBuilder = (AssemblyBuilder)StrongNamedModule.Assembly;
 				assemblyFileName = StrongNamedModuleName;
+#if NET9_0_OR_GREATER
+				assemblyFilePath = weakModulePath;
+#else
 				assemblyFilePath = StrongNamedModule.FullyQualifiedName;
+#endif
 			}
 			else
 			{
@@ -460,7 +479,11 @@ private AssemblyName GetAssemblyName(bool signStrongName)
 				}
 				assemblyBuilder = (AssemblyBuilder)WeakNamedModule.Assembly;
 				assemblyFileName = WeakNamedModuleName;
+#if NET9_0_OR_GREATER
+				assemblyFilePath = weakModulePath;
+#else
 				assemblyFilePath = WeakNamedModule.FullyQualifiedName;
+#endif
 			}
 
 			if (File.Exists(assemblyFilePath))
@@ -472,7 +495,12 @@ private AssemblyName GetAssemblyName(bool signStrongName)
 			AddCacheMappings(assemblyBuilder);
 #endif
 
+#if FEATURE_ASSEMBLYBUILDER_SAVE
 			assemblyBuilder.Save(assemblyFileName);
+#elif NET9_0_OR_GREATER
+			var persistedAssemblyBuilder = (PersistedAssemblyBuilder)assemblyBuilder;
+			persistedAssemblyBuilder.Save(assemblyFilePath);
+#endif
 			return assemblyFilePath;
 		}
 #endif

src/Castle.Core/DynamicProxy/PersistentProxyBuilder.cs

@@ -12,12 +12,16 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#if FEATURE_ASSEMBLYBUILDER_SAVE
+#if FEATURE_ASSEMBLYBUILDER_SAVE || NET9_0_OR_GREATER
 
 #nullable enable
 
 namespace Castle.DynamicProxy
 {
+#if NET9_0_OR_GREATER
+	using System.IO;
+#endif
+
 	/// <summary>
 	///   ProxyBuilder that persists the generated type.
 	/// </summary>
@@ -43,7 +47,17 @@ public PersistentProxyBuilder() : base(new ModuleScope(true))
 		/// </remarks>
 		public string? SaveAssembly()
 		{
+#if NET9_0_OR_GREATER
+			var assemblyPath = lastScope.WeakNamedModule != null ? lastScope.WeakNamedModuleName : lastScope.StrongNamedModuleName;
+			using var file = File.Create(assemblyPath);
+			lastAssemblyGenerated.Seek(0, SeekOrigin.Begin);
+			lastAssemblyGenerated.CopyTo(file);
+			file.Flush();
+			file.Close();
+			return assemblyPath;
+#else
 			return ModuleScope.SaveAssembly();
+#endif
 		}
 	}
 }