1 files changed, 175 insertions, 0 deletions
diff --git a/Mono.Cecil/GenericParameterResolver.cs b/Mono.Cecil/GenericParameterResolver.cs
new file mode 100644
index 0000000..86525c5
--- /dev/null
+++ b/Mono.Cecil/GenericParameterResolver.cs
@@ -0,0 +1,175 @@
+using Mono.Cecil.Cil;
+using System;
+
+namespace Mono.Cecil {
+	internal sealed class GenericParameterResolver {
+		internal static TypeReference ResolveReturnTypeIfNeeded (MethodReference methodReference)
+		{
+			if (methodReference.DeclaringType.IsArray && methodReference.Name == "Get")
+				return methodReference.ReturnType;
+
+			var genericInstanceMethod = methodReference as GenericInstanceMethod;
+			var declaringGenericInstanceType = methodReference.DeclaringType as GenericInstanceType;
+
+			if (genericInstanceMethod == null && declaringGenericInstanceType == null)
+				return methodReference.ReturnType;
+
+			return ResolveIfNeeded (genericInstanceMethod, declaringGenericInstanceType, methodReference.ReturnType);
+		}
+
+		internal static TypeReference ResolveFieldTypeIfNeeded (FieldReference fieldReference)
+		{
+			return ResolveIfNeeded (null, fieldReference.DeclaringType as GenericInstanceType, fieldReference.FieldType);
+		}
+
+		internal static TypeReference ResolveParameterTypeIfNeeded (MethodReference method, ParameterReference parameter)
+		{
+			var genericInstanceMethod = method as GenericInstanceMethod;
+			var declaringGenericInstanceType = method.DeclaringType as GenericInstanceType;
+
+			if (genericInstanceMethod == null && declaringGenericInstanceType == null)
+				return parameter.ParameterType;
+
+			return ResolveIfNeeded (genericInstanceMethod, declaringGenericInstanceType, parameter.ParameterType);
+		}
+
+		internal static TypeReference ResolveVariableTypeIfNeeded (MethodReference method, VariableReference variable)
+		{
+			var genericInstanceMethod = method as GenericInstanceMethod;
+			var declaringGenericInstanceType = method.DeclaringType as GenericInstanceType;
+
+			if (genericInstanceMethod == null && declaringGenericInstanceType == null)
+				return variable.VariableType;
+
+			return ResolveIfNeeded (genericInstanceMethod, declaringGenericInstanceType, variable.VariableType);
+		}
+
+		private static TypeReference ResolveIfNeeded (IGenericInstance genericInstanceMethod, IGenericInstance declaringGenericInstanceType, TypeReference parameterType)
+		{
+			var byRefType = parameterType as ByReferenceType;
+			if (byRefType != null)
+				return ResolveIfNeeded (genericInstanceMethod, declaringGenericInstanceType, byRefType);
+
+			var arrayType = parameterType as ArrayType;
+			if (arrayType != null)
+				return ResolveIfNeeded (genericInstanceMethod, declaringGenericInstanceType, arrayType);
+
+			var genericInstanceType = parameterType as GenericInstanceType;
+			if (genericInstanceType != null)
+				return ResolveIfNeeded (genericInstanceMethod, declaringGenericInstanceType, genericInstanceType);
+
+			var genericParameter = parameterType as GenericParameter;
+			if (genericParameter != null)
+				return ResolveIfNeeded (genericInstanceMethod, declaringGenericInstanceType, genericParameter);
+
+			var requiredModifierType = parameterType as RequiredModifierType;
+			if (requiredModifierType != null && ContainsGenericParameters (requiredModifierType))
+				return ResolveIfNeeded (genericInstanceMethod, declaringGenericInstanceType, requiredModifierType.ElementType);
+
+			if (ContainsGenericParameters (parameterType))
+				throw new Exception ("Unexpected generic parameter.");
+
+			return parameterType;
+		}
+
+		private static TypeReference ResolveIfNeeded (IGenericInstance genericInstanceMethod, IGenericInstance genericInstanceType, GenericParameter genericParameterElement)
+		{
+			return (genericParameterElement.MetadataType == MetadataType.MVar)
+				? (genericInstanceMethod != null ? genericInstanceMethod.GenericArguments[genericParameterElement.Position] : genericParameterElement)
+				: genericInstanceType.GenericArguments[genericParameterElement.Position];
+		}
+
+		private static ArrayType ResolveIfNeeded (IGenericInstance genericInstanceMethod, IGenericInstance genericInstanceType, ArrayType arrayType)
+		{
+			return new ArrayType (ResolveIfNeeded (genericInstanceMethod, genericInstanceType, arrayType.ElementType), arrayType.Rank);
+		}
+
+		private static ByReferenceType ResolveIfNeeded (IGenericInstance genericInstanceMethod, IGenericInstance genericInstanceType, ByReferenceType byReferenceType)
+		{
+			return new ByReferenceType (ResolveIfNeeded (genericInstanceMethod, genericInstanceType, byReferenceType.ElementType));
+		}
+
+		private static GenericInstanceType ResolveIfNeeded (IGenericInstance genericInstanceMethod, IGenericInstance genericInstanceType, GenericInstanceType genericInstanceType1)
+		{
+			if (!ContainsGenericParameters (genericInstanceType1))
+				return genericInstanceType1;
+
+			var newGenericInstance = new GenericInstanceType (genericInstanceType1.ElementType);
+
+			foreach (var genericArgument in genericInstanceType1.GenericArguments) {
+				if (!genericArgument.IsGenericParameter) {
+					newGenericInstance.GenericArguments.Add (ResolveIfNeeded (genericInstanceMethod, genericInstanceType, genericArgument));
+					continue;
+				}
+
+				var genParam = (GenericParameter)genericArgument;
+
+				switch (genParam.Type) {
+					case GenericParameterType.Type: {
+							if (genericInstanceType == null)
+								throw new NotSupportedException ();
+
+							newGenericInstance.GenericArguments.Add (genericInstanceType.GenericArguments[genParam.Position]);
+						}
+						break;
+
+					case GenericParameterType.Method: {
+							if (genericInstanceMethod == null)
+								newGenericInstance.GenericArguments.Add (genParam);
+							else
+								newGenericInstance.GenericArguments.Add (genericInstanceMethod.GenericArguments[genParam.Position]);
+						}
+						break;
+				}
+			}
+
+			return newGenericInstance;
+		}
+
+		private static bool ContainsGenericParameters (TypeReference typeReference)
+		{
+			var genericParameter = typeReference as GenericParameter;
+			if (genericParameter != null)
+				return true;
+
+			var arrayType = typeReference as ArrayType;
+			if (arrayType != null)
+				return ContainsGenericParameters (arrayType.ElementType);
+
+			var pointerType = typeReference as PointerType;
+			if (pointerType != null)
+				return ContainsGenericParameters (pointerType.ElementType);
+
+			var byRefType = typeReference as ByReferenceType;
+			if (byRefType != null)
+				return ContainsGenericParameters (byRefType.ElementType);
+
+			var sentinelType = typeReference as SentinelType;
+			if (sentinelType != null)
+				return ContainsGenericParameters (sentinelType.ElementType);
+
+			var pinnedType = typeReference as PinnedType;
+			if (pinnedType != null)
+				return ContainsGenericParameters (pinnedType.ElementType);
+
+			var requiredModifierType = typeReference as RequiredModifierType;
+			if (requiredModifierType != null)
+				return ContainsGenericParameters (requiredModifierType.ElementType);
+
+			var genericInstance = typeReference as GenericInstanceType;
+			if (genericInstance != null) {
+				foreach (var genericArgument in genericInstance.GenericArguments) {
+					if (ContainsGenericParameters (genericArgument))
+						return true;
+				}
+
+				return false;
+			}
+
+			if (typeReference is TypeSpecification)
+				throw new NotSupportedException ();
+
+			return false;
+		}
+	}
+}