Add support for internal metadata view interfaces

src/Microsoft.VisualStudio.Composition/Configuration/MetadataViewGenerator.cs

@@ -9,16 +9,14 @@
 namespace Microsoft.VisualStudio.Composition
 {
     using System;
-    using System.Collections;
     using System.Collections.Generic;
-    using System.ComponentModel;
     using System.Globalization;
     using System.Linq;
     using System.Reflection;
     using System.Reflection.Emit;
     using System.Security;
     using System.Threading;
-    using Microsoft.Internal;
+    using Microsoft.VisualStudio.Composition.Reflection;
 
     /// <summary>
     /// Constructs concrete types for metadata view interfaces.
@@ -90,6 +88,7 @@ internal static class MetadataViewGenerator
         private static readonly ConstructorInfo ObjectCtor = typeof(object).GetConstructor(Type.EmptyTypes);
 
         private static ModuleBuilder transparentProxyModuleBuilder;
+        private static SkipClrVisibilityChecks skipClrVisibilityChecks;
 
         public delegate object MetadataViewFactory(IReadOnlyDictionary<string, object> metadata, IReadOnlyDictionary<string, object> defaultMetadata);
 
@@ -106,6 +105,7 @@ private static ModuleBuilder GetProxyModuleBuilder()
                 // make a new assemblybuilder and modulebuilder
                 var assemblyBuilder = CreateProxyAssemblyBuilder(typeof(SecurityTransparentAttribute).GetConstructor(Type.EmptyTypes));
                 transparentProxyModuleBuilder = assemblyBuilder.DefineDynamicModule("MetadataViewProxiesModule");
+                skipClrVisibilityChecks = new SkipClrVisibilityChecks(assemblyBuilder, transparentProxyModuleBuilder);
             }
 
             return transparentProxyModuleBuilder;
@@ -142,6 +142,8 @@ private static Type GenerateInterfaceViewProxyType(Type viewType)
             Type[] interfaces = { viewType };
 
             var proxyModuleBuilder = GetProxyModuleBuilder();
+            skipClrVisibilityChecks.SkipVisibilityChecksFor(viewType.GetTypeInfo());
+
             proxyTypeBuilder = proxyModuleBuilder.DefineType(
                 string.Format(CultureInfo.InvariantCulture, "_proxy_{0}_{1}", viewType.FullName, Guid.NewGuid()),
                 TypeAttributes.Public,

src/Microsoft.VisualStudio.Composition/Reflection/SkipClrVisibilityChecks.cs

@@ -0,0 +1,142 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+namespace Microsoft.VisualStudio.Composition.Reflection
+{
+    using System;
+    using System.Collections.Generic;
+    using System.Reflection;
+    using System.Reflection.Emit;
+
+    /// <summary>
+    /// Gives a dynamic assembly the ability to skip CLR visibility checks,
+    /// allowing the assembly to access private members of another assembly.
+    /// </summary>
+    internal class SkipClrVisibilityChecks
+    {
+        /// <summary>
+        /// The assembly builder that is constructing the dynamic assembly.
+        /// </summary>
+        private readonly AssemblyBuilder assemblyBuilder;
+
+        /// <summary>
+        /// The module builder for the default module of the <see cref="assemblyBuilder"/>.
+        /// This is where the special attribute will be defined.
+        /// </summary>
+        private readonly ModuleBuilder moduleBuilder;
+
+        /// <summary>
+        /// The set of assemblies that already have visibility checks skipped for.
+        /// </summary>
+        private readonly HashSet<string> attributedAssemblyNames = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
+
+        /// <summary>
+        /// The constructor on the special attribute to reference for each skipped assembly.
+        /// </summary>
+        private ConstructorInfo magicAttributeCtor;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="SkipClrVisibilityChecks"/> class.
+        /// </summary>
+        /// <param name="assemblyBuilder">The builder for the dynamic assembly.</param>
+        /// <param name="moduleBuilder">The builder for the default module defined by <see cref="assemblyBuilder"/>.</param>
+        internal SkipClrVisibilityChecks(AssemblyBuilder assemblyBuilder, ModuleBuilder moduleBuilder)
+        {
+            Requires.NotNull(assemblyBuilder, nameof(assemblyBuilder));
+            Requires.NotNull(moduleBuilder, nameof(moduleBuilder));
+            this.assemblyBuilder = assemblyBuilder;
+            this.moduleBuilder = moduleBuilder;
+        }
+
+        /// <summary>
+        /// Ensures the CLR will skip visibility checks when accessing
+        /// the assembly that contains the specified member.
+        /// </summary>
+        /// <param name="memberInfo">The member that may not be publicly accessible.</param>
+        internal void SkipVisibilityChecksFor(MemberInfo memberInfo)
+        {
+            this.SkipVisibilityChecksFor(memberInfo.Module.Assembly);
+        }
+
+        /// <summary>
+        /// Add an attribute to the dynamic assembly so that the CLR will skip visibility checks
+        /// for the specified assembly.
+        /// </summary>
+        /// <param name="assembly">The assembly to skip visibility checks for.</param>
+        private void SkipVisibilityChecksFor(Assembly assembly)
+        {
+            Requires.NotNull(assembly, nameof(assembly));
+            var assemblyName = assembly.GetName();
+            this.SkipVisibilityChecksFor(assemblyName);
+        }
+
+        /// <summary>
+        /// Add an attribute to the dynamic assembly so that the CLR will skip visibility checks
+        /// for the assembly with the specified name.
+        /// </summary>
+        /// <param name="assemblyName">The name of the assembly to skip visibility checks for.</param>
+        private void SkipVisibilityChecksFor(AssemblyName assemblyName)
+        {
+            Requires.NotNull(assemblyName, nameof(assemblyName));
+
+            string assemblyNameArg = assemblyName.Name;
+            if (this.attributedAssemblyNames.Add(assemblyNameArg))
+            {
+                var cab = new CustomAttributeBuilder(this.GetMagicAttributeCtor(), new object[] { assemblyNameArg });
+                this.assemblyBuilder.SetCustomAttribute(cab);
+            }
+        }
+
+        /// <summary>
+        /// Gets the constructor to the IgnoresAccessChecksToAttribute, generating the attribute if necessary.
+        /// </summary>
+        /// <returns>The constructor to the IgnoresAccessChecksToAttribute.</returns>
+        private ConstructorInfo GetMagicAttributeCtor()
+        {
+            if (this.magicAttributeCtor == null)
+            {
+                var magicAttribute = this.EmitMagicAttribute();
+                this.magicAttributeCtor = magicAttribute.GetConstructor(new Type[] { typeof(string) });
+            }
+
+            return this.magicAttributeCtor;
+        }
+
+        /// <summary>
+        /// Defines the special IgnoresAccessChecksToAttribute type in the <see cref="moduleBuilder"/>.
+        /// </summary>
+        /// <returns>The generated attribute type.</returns>
+        private TypeInfo EmitMagicAttribute()
+        {
+            var tb = this.moduleBuilder.DefineType(
+                "System.Runtime.CompilerServices.IgnoresAccessChecksToAttribute",
+                TypeAttributes.NotPublic,
+                typeof(Attribute));
+
+            var attributeUsageCtor = typeof(AttributeUsageAttribute).GetConstructor(
+                new Type[] { typeof(AttributeTargets) });
+            var attributeUsage = new CustomAttributeBuilder(
+                attributeUsageCtor,
+                new object[] { AttributeTargets.Assembly },
+                new PropertyInfo[] { typeof(AttributeUsageAttribute).GetProperty(nameof(AttributeUsageAttribute.AllowMultiple)) },
+                new object[] { false });
+            tb.SetCustomAttribute(attributeUsage);
+
+            var cb = tb.DefineConstructor(
+                MethodAttributes.Public |
+                MethodAttributes.HideBySig |
+                MethodAttributes.SpecialName |
+                MethodAttributes.RTSpecialName,
+                CallingConventions.Standard,
+                new Type[] { typeof(string) });
+            cb.DefineParameter(1, ParameterAttributes.None, "assemblyName");
+
+            var il = cb.GetILGenerator();
+            il.Emit(OpCodes.Ldarg_0);
+            ConstructorInfo attrBaseCtor = typeof(Attribute).GetConstructor(BindingFlags.NonPublic | BindingFlags.Instance, null, new Type[0], null);
+            il.Emit(OpCodes.Call, attrBaseCtor);
+            il.Emit(OpCodes.Ret);
+
+            return tb.CreateTypeInfo();
+        }
+    }
+}

src/tests/Microsoft.VisualStudio.Composition.AssemblyDiscoveryTests/AssemblyInfo.cs

@@ -0,0 +1,8 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using System.Runtime.CompilerServices;
+
+// This is an important part of testing. We need to know that our ability to handle
+// internal types can span assemblies when, for example, an internal type in one assembly
+// references an internal type in another assembly.
+[assembly: InternalsVisibleTo("Microsoft.VisualStudio.Composition.Tests")]

src/tests/Microsoft.VisualStudio.Composition.AssemblyDiscoveryTests/IInternalMetadataView.cs

@@ -0,0 +1,13 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+namespace Microsoft.VisualStudio.Composition.AssemblyDiscoveryTests
+{
+    /// <summary>
+    /// An internal interface that is used as the base interface
+    /// of a metadata view defined in another assembly.
+    /// </summary>
+    internal interface IInternalMetadataView
+    {
+        string MetadataOnInternalInterface { get; }
+    }
+}

src/tests/Microsoft.VisualStudio.Composition.Tests/ExportMetadataTests.cs

@@ -107,6 +107,19 @@ public void ImportManyWithMetadataInterface(IContainer container)
             Assert.IsType<PartWithExportMetadata>(importingPart.ImportingProperty.Single().Value);
         }
 
+        [Trait("Access", "NonPublic")]
+        [MefFact(CompositionEngines.V3EmulatingV1, typeof(ImportManyPartWithInternalMetadataInterface), typeof(PartWithExportMetadata))]
+        public void ImportManyWithInternalMetadataInterface(IContainer container)
+        {
+            var importingPart = container.GetExportedValue<ImportManyPartWithInternalMetadataInterface>();
+            Assert.NotNull(importingPart.ImportingProperty);
+            Assert.Equal(1, importingPart.ImportingProperty.Count());
+            Assert.Equal("b", importingPart.ImportingProperty.Single().Metadata.a);
+            Assert.Equal("internal!", importingPart.ImportingProperty.Single().Metadata.MetadataOnInternalInterface);
+            Assert.False(importingPart.ImportingProperty.Single().IsValueCreated);
+            Assert.IsType<PartWithExportMetadata>(importingPart.ImportingProperty.Single().Value);
+        }
+
         [MefFact(CompositionEngines.Unspecified, typeof(ImportingPartWithMetadataInterface), typeof(PartWithExportMetadata))]
         [Trait("Efficiency", "InstanceReuse")]
         public void MetadataViewInterfaceInstanceSharedAcrossImports(IContainer container)
@@ -552,8 +565,10 @@ public class PartImportingPartWithNamesSingleMetadata
 
         [MefV1.Export, MefV1.PartCreationPolicy(MefV1.CreationPolicy.NonShared)]
         [MefV1.ExportMetadata("a", "b")]
+        [MefV1.ExportMetadata(nameof(AssemblyDiscoveryTests.IInternalMetadataView.MetadataOnInternalInterface), "internal!")]
         [Export]
         [ExportMetadata("a", "b")]
+        [ExportMetadata(nameof(AssemblyDiscoveryTests.IInternalMetadataView.MetadataOnInternalInterface), "internal!")]
         public class PartWithExportMetadata { }
 
         [MefV1.Export, MefV1.PartCreationPolicy(MefV1.CreationPolicy.NonShared)]
@@ -604,6 +619,14 @@ public class ImportManyPartWithMetadataInterface
             public IEnumerable<Lazy<PartWithExportMetadata, IMetadata>> ImportingProperty { get; set; }
         }
 
+        [MefV1.Export, MefV1.PartCreationPolicy(MefV1.CreationPolicy.NonShared)]
+        [Export]
+        public class ImportManyPartWithInternalMetadataInterface
+        {
+            [ImportMany, MefV1.ImportMany]
+            internal IEnumerable<Lazy<PartWithExportMetadata, IMetadataInternal>> ImportingProperty { get; set; }
+        }
+
         [MefV1.Export, MefV1.PartCreationPolicy(MefV1.CreationPolicy.NonShared)]
         [Export]
         public class ImportManyPartWithMetadataClass
@@ -637,6 +660,10 @@ public interface IMetadata : IMetadataBase
             int SomeInt { get; }
         }
 
+        internal interface IMetadataInternal : IMetadata, AssemblyDiscoveryTests.IInternalMetadataView
+        {
+        }
+
         public class MetadataClass
         {
             // Only MEFv1 requires this constructor -- MEFv2 doesn't need it.

src/tests/Microsoft.VisualStudio.Composition.Tests/ExportProviderTests.cs

@@ -54,6 +54,15 @@ public void GetExportWithMetadataView(IContainer container)
             Assert.NotNull(export.Value);
         }
 
+        [Trait("Access", "NonPublic")]
+        [MefFact(CompositionEngines.V3EmulatingV1 | CompositionEngines.V3EmulatingV2, typeof(SomeOtherPart))]
+        public void GetExportWithInternalMetadataView(IContainer container)
+        {
+            var export = container.GetExport<SomeOtherPart, ISomeOtherPartInternalMetadataView>();
+            Assert.Equal(1, export.Metadata.A);
+            Assert.NotNull(export.Value);
+        }
+
         [MefFact(CompositionEngines.V1Compat | CompositionEngines.V3EmulatingV2, typeof(SomeOtherPart))]
         public void GetExportWithFilteringMetadataView(IContainer container)
         {
@@ -118,6 +127,11 @@ public interface ISomeOtherPartMetadataView
             int A { get; }
         }
 
+        internal interface ISomeOtherPartInternalMetadataView
+        {
+            int A { get; }
+        }
+
         public interface IMetadataViewWithBMember
         {
             int B { get; }