Introducing Mono.Cecil

This change modifies a little the architecture around Reflection.

- Using Mono.Cecil for reflecting assemblies
- Added assembly abstraction layer in order to limit the use of Cecil to
one single project only (avoiding dep spreading across the product and
tests)
- Added layer for assembly loading strategies

Verified that assemblies are correctly loaded without any need to load
external dependencies on that one. IL parsing executed fine and
attribute info available.

Unfortunately `System.Reflection` triggers many problems:
- If the assembly is loaded in reflection-only-context,
custom-attributes are not available.
- In order to have custom-attributes available, tried loading assembly
in normal exec context. Failure occurs as the assembly references other
assemblies (`mscorlib` and `Script.Import.dll`) which cannot be found.

src/Reflection.ScriptSharp/ASTBuilder.cs

@@ -6,8 +6,9 @@
 namespace Rosetta.Reflection.ScriptSharp
 {
     using System;
-    using System.Reflection;
+    using System.IO;
 
+    using Rosetta.Reflection.Proxies;
     using Rosetta.Reflection.ScriptSharp.Helpers;
 
     /// <summary>
@@ -21,12 +22,17 @@ public class ASTBuilder : Rosetta.Reflection.ASTBuilder
         /// This class builds a plain tree from all the types in the assembly and considers the ScriptSharp 
         /// namespace substitution attribute <code>ScriptNamespace</code>.
         /// </summary>
-        /// <param name="assembly">The path to the assembly.</param>
-        public ASTBuilder(Assembly assembly) : base(assembly)
+        /// <param name="assembly">The assembly.</param>
+        /// <param name="rawAssembly">
+        /// The raw assembly to be used to create the <see cref="Compilation"/> object. 
+        /// If not provided, the builder will return an <see cref="ASTInfo"/> where <see cref="ASTInfo.CompilationUnit"/> is <code>null</code>.
+        /// </param>
+        public ASTBuilder(IAssemblyProxy assembly, Stream rawAssembly = null) 
+            : base(assembly, rawAssembly)
         {
         }
 
-        protected override Rosetta.Reflection.Helpers.Namespace CreateNamespaceHelper(System.Reflection.TypeInfo type)
+        protected override Rosetta.Reflection.Helpers.Namespace CreateNamespaceHelper(ITypeInfoProxy type)
         {
             return new Namespace(type);
         }

src/Reflection.ScriptSharp/ProgramWrapper.cs

@@ -6,7 +6,9 @@
 namespace Rosetta.Reflection.ScriptSharp
 {
     using System;
-    using System.Reflection;
+    using System.IO;
+
+    using Rosetta.Reflection.Proxies;
 
     /// <summary>
     /// Initiates the translation.
@@ -22,6 +24,6 @@ public ProgramWrapper(string assemblyPath)
         {
         }
 
-        protected override IASTBuilder CreateASTBuilder(Assembly assembly) => new ASTBuilder(assembly);
+        protected override IASTBuilder CreateASTBuilder(IAssemblyProxy assembly, Stream rawAssembly) => new ASTBuilder(assembly, rawAssembly);
     }
 }

src/Reflection.ScriptSharp/Reflection.ScriptSharp.csproj

@@ -85,7 +85,7 @@
       <Private>True</Private>
     </Reference>
     <Reference Include="System.Configuration" />
-    <Reference Include="System.Reflection.Metadata, Version=1.2.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
+	<Reference Include="System.Reflection.Metadata, Version=1.2.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
       <HintPath>..\..\packages\System.Reflection.Metadata.1.2.0\lib\portable-net45+win8\System.Reflection.Metadata.dll</HintPath>
       <Private>True</Private>
     </Reference>
@@ -113,7 +113,9 @@
       <Name>Reflection</Name>
     </ProjectReference>
   </ItemGroup>
-  <ItemGroup />
+  <ItemGroup>
+    <None Include="app.config" />
+  </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
        Other similar extension points exist, see Microsoft.Common.targets.

src/Reflection.ScriptSharp/app.config

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="utf-8"?>
+<configuration>
+  <runtime>
+    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
+      <dependentAssembly>
+        <assemblyIdentity name="System.Reflection" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
+        <bindingRedirect oldVersion="0.0.0.0-4.1.1.0" newVersion="4.1.1.0" />
+      </dependentAssembly>
+    </assemblyBinding>
+  </runtime>
+</configuration>

src/Reflection.ScriptSharp/helpers/Namespace.cs

@@ -7,7 +7,8 @@ namespace Rosetta.Reflection.ScriptSharp.Helpers
 {
     using System;
     using System.Collections.Generic;
-    using System.Reflection;
+
+    using Rosetta.Reflection.Proxies;
 
     /// <summary>
     /// Helper for <see cref="TypeInfo"/> in order to retrieve information about its namespace.
@@ -21,7 +22,7 @@ public class Namespace : Rosetta.Reflection.Helpers.Namespace
         /// Initializes a new instance of the <see cref="Namespace"/> class.
         /// </summary>
         /// <param name="type"></param>
-        public Namespace(TypeInfo type) : base(type)
+        public Namespace(ITypeInfoProxy type) : base(type)
         {
         }
 
@@ -40,7 +41,17 @@ public override string FullName
                 {
                     this.fullName = base.FullName;
 
-                    foreach (CustomAttributeData attribute in this.Type.CustomAttributes)
+                    IEnumerable<ICustomAttributeDataProxy> customAttributes = null;
+                    try
+                    {
+                        customAttributes = this.Type.CustomAttributes;
+                    } catch (TypeLoadException e)
+                    {
+                        // Could not access the attributes NEEDED???
+                        return this.fullName;
+                    }
+
+                    foreach (ICustomAttributeDataProxy attribute in customAttributes)
                     {
                         if (ScriptNamespaceAttributeDecoration.IsScriptNamespaceAttributeDecoration(attribute.AttributeType))
                         {

src/Reflection.ScriptSharp/helpers/ScriptNamespaceAttributeDecoration.cs

@@ -6,9 +6,8 @@
 namespace Rosetta.Reflection.ScriptSharp.Helpers
 {
     using System;
-    using System.Collections.Generic;
-    using System.Linq;
-    using System.Reflection;
+
+    using Rosetta.Reflection.Proxies;
 
     /// <summary>
     /// Abstraction for building an AST from an assembly.
@@ -18,7 +17,7 @@ public class ScriptNamespaceAttributeDecoration
         public const string ScriptNamespaceName = "ScriptNamespace";
         public const string ScriptNamespaceFullName = "ScriptNamespace"; // TODO: Find namespace used by ScriptSharp for this class
 
-        private readonly CustomAttributeData attributeData;
+        private readonly ICustomAttributeDataProxy attributeData;
 
         // Cached values
         private string overridenNamespace;
@@ -27,7 +26,7 @@ public class ScriptNamespaceAttributeDecoration
         /// Initializes a new instance of the <see cref="Namespace"/> class.
         /// </summary>
         /// <param name="attributeData"></param>
-        public ScriptNamespaceAttributeDecoration(CustomAttributeData attributeData)
+        public ScriptNamespaceAttributeDecoration(ICustomAttributeDataProxy attributeData)
         {
             if (attributeData == null)
             {
@@ -71,7 +70,7 @@ public string OverridenNamespace
         /// </summary>
         /// <param name="attribute"></param>
         /// <returns></returns>
-        public static bool IsScriptNamespaceAttributeDecoration(Type attribute)
+        public static bool IsScriptNamespaceAttributeDecoration(ITypeProxy attribute)
         {
             return attribute.Name == ScriptNamespaceFullName;
         }

src/Reflection/ASTBuilder.cs

@@ -8,15 +8,14 @@ namespace Rosetta.Reflection
     using System;
     using System.Collections.Generic;
     using System.IO;
-    using System.Linq;
-    using System.Reflection;
-    using System.Text;
+    using System.Runtime.Serialization.Formatters.Binary;
 
     using Microsoft.CodeAnalysis;
     using Microsoft.CodeAnalysis.CSharp;
     using Microsoft.CodeAnalysis.CSharp.Syntax;
 
     using Rosetta.Reflection.Helpers;
+    using Rosetta.Reflection.Proxies;
 
     /// <summary>
     /// Builds an AST from an assembly.
@@ -29,7 +28,8 @@ namespace Rosetta.Reflection
     /// </remarks>
     public class ASTBuilder : IASTBuilder
     {
-        private readonly Assembly assembly;
+        private readonly IAssemblyProxy assembly;
+        private readonly Stream rawAssembly;
 
         // Cached quantities
         private ASTInfo astInfo;
@@ -39,14 +39,19 @@ public class ASTBuilder : IASTBuilder
         /// This class builds a plain tree from all the types in the assembly.
         /// </summary>
         /// <param name="assembly">The path to the assembly.</param>
-        public ASTBuilder(Assembly assembly)
+        /// <param name="rawAssembly">
+        /// The raw assembly to be used to create the <see cref="Compilation"/> object. 
+        /// If not provided, the builder will return an <see cref="ASTInfo"/> where <see cref="ASTInfo.CompilationUnit"/> is <code>null</code>.
+        /// </param>
+        public ASTBuilder(IAssemblyProxy assembly, Stream rawAssembly = null)
         {
             if (assembly == null)
             {
                 throw new ArgumentNullException(nameof(assembly));
             }
 
             this.assembly = assembly;
+            this.rawAssembly = rawAssembly;
         }
 
         /// <summary>
@@ -60,29 +65,14 @@ public ASTInfo Build()
                 return this.astInfo;
             }
 
-            IEnumerable<System.Reflection.TypeInfo> types = null;
+            IEnumerable<ITypeInfoProxy> types = null;
             try
             {
                 types = this.assembly.DefinedTypes;
             }
-            catch(ReflectionTypeLoadException ex)
+            catch(Exception ex)
             {
-                var errorMessage = new StringBuilder();
-                errorMessage.AppendLine($"Error loading defined types in assembly {this.assembly.FullName}. Found {ex.LoaderExceptions.Length} errors:");
-
-                foreach (var innerException in ex.LoaderExceptions)
-                {
-                    errorMessage.AppendLine($"{innerException.GetType().Name} - {innerException.HResult}: {innerException.Message}");
-                }
-
-                // Try to get all the available types
-                types = ex.Types.Where(t => t != null).Select(IntrospectionExtensions.GetTypeInfo);
-
-                if (types == null || types.Count() == 0)
-                {
-                    // Rethrow by emitting all errors
-                    throw new InvalidOperationException(errorMessage.ToString(), ex);
-                }
+                throw new InvalidOperationException("An error occurred while trying to load defined types", ex);
             }
 
             var nodes = new List<MemberDeclarationSyntax>();
@@ -117,43 +107,42 @@ public ASTInfo Build()
             };
         }
 
-        private MemberDeclarationSyntax BuildClassNode(System.Reflection.TypeInfo type)
+        private MemberDeclarationSyntax BuildClassNode(ITypeInfoProxy type)
         {
             return this.BuildNode(type, SyntaxFactory.ClassDeclaration);
         }
 
-        private MemberDeclarationSyntax BuildStructNode(System.Reflection.TypeInfo type)
+        private MemberDeclarationSyntax BuildStructNode(ITypeInfoProxy type)
         {
             return this.BuildNode(type, SyntaxFactory.StructDeclaration);
         }
 
-        private MemberDeclarationSyntax BuildEnumNode(System.Reflection.TypeInfo type)
+        private MemberDeclarationSyntax BuildEnumNode(ITypeInfoProxy type)
         {
             return this.BuildNode(type, SyntaxFactory.EnumDeclaration);
         }
 
-        private MemberDeclarationSyntax BuildInterfaceNode(System.Reflection.TypeInfo type)
+        private MemberDeclarationSyntax BuildInterfaceNode(ITypeInfoProxy type)
         {
             return this.BuildNode(type, SyntaxFactory.InterfaceDeclaration);
         }
 
         private Compilation BuildCompilationUnit(SyntaxTree tree)
         {
-            var references = new List<MetadataReference>();
-
-            using (var stream = new MemoryStream())
+            if (this.rawAssembly == null)
             {
-                var bf = new System.Runtime.Serialization.Formatters.Binary.BinaryFormatter();
-                bf.Serialize(stream, this.assembly);
-
-                var metadataReference = MetadataReference.CreateFromStream(stream);
-                references.Add(metadataReference);
+                return null;
             }
-
+
+            var references = new List<MetadataReference>();
+
+            var metadataReference = MetadataReference.CreateFromStream(this.rawAssembly);
+            references.Add(metadataReference);
+
             return CSharpCompilation.Create("GeneratedCompilation", new[] { tree }, references);
         }
 
-        private MemberDeclarationSyntax BuildNode(System.Reflection.TypeInfo type, RoslynNodeFactory factory)
+        private MemberDeclarationSyntax BuildNode(ITypeInfoProxy type, RoslynNodeFactory factory)
         {
             var helper = this.CreateNamespaceHelper(type);
 
@@ -175,7 +164,7 @@ private MemberDeclarationSyntax BuildNode(System.Reflection.TypeInfo type, Rosly
             return node;
         }
 
-        protected virtual Namespace CreateNamespaceHelper(System.Reflection.TypeInfo type)
+        protected virtual Namespace CreateNamespaceHelper(ITypeInfoProxy type)
         {
             return new Namespace(type);
         }