/// <summary>
/// Creates a method that matches the signature defined in the
/// <paramref name="method"/> parameter.
/// </summary>
/// <param name="targetType">The type that will host the new method.</param>
/// <param name="method">The method from which the signature will be derived.</param>
public virtual MethodDefinition CreateMethod(TypeDefinition targetType, MethodInfo method)
{
#region Match the method signature
ModuleDefinition module = targetType.Module;
string methodName = method.Name;
// If the method is a member defined on an interface type,
// we need to rename the method to avoid
// any naming conflicts in the type itself
if (method.DeclaringType.IsInterface)
{
string parentName = method.DeclaringType.FullName;
// Rename the parent type to its fully qualified name
// if it is a generic type
methodName = string.Format("{0}.{1}", parentName, methodName);
}
MethodAttributes baseAttributes = MethodAttributes.Virtual |
MethodAttributes.HideBySig;
MethodAttributes attributes = default(MethodAttributes);
#region Match the visibility of the target method
if (method.IsFamilyOrAssembly)
attributes = baseAttributes | MethodAttributes.FamORAssem;
if (method.IsFamilyAndAssembly)
attributes = baseAttributes | MethodAttributes.FamANDAssem;
if (method.IsPublic)
attributes = baseAttributes | MethodAttributes.Public;
#endregion
// Build the list of parameter types
Type[] parameterTypes = (from param in method.GetParameters()
let type = param.ParameterType
let importedType = type
select importedType).ToArray();
//Build the list of generic parameter types
Type[] genericParameterTypes = method.GetGenericArguments();
MethodDefinition newMethod = targetType.DefineMethod(methodName, attributes,
method.ReturnType, parameterTypes,
genericParameterTypes);
newMethod.Body.InitLocals = true;
newMethod.ImplAttributes = MethodImplAttributes.IL | MethodImplAttributes.Managed;
newMethod.HasThis = true;
// Match the generic type arguments
Type[] typeArguments = method.GetGenericArguments();
if (typeArguments != null || typeArguments.Length > 0)
MatchGenericArguments(newMethod, typeArguments);
MethodReference originalMethodRef = module.Import(method);
newMethod.Overrides.Add(originalMethodRef);
#endregion
// Define the method body
if (Emitter != null)
Emitter.Emit(method, newMethod);
return newMethod;
}
/// <summary>
/// Defines the factory method on the singleton type.
/// </summary>
/// <param name="singletonType">The singleton type that will be generated by the emitter.</param>
/// <param name="il">The <see cref="ILProcessor"/> instance that points to the target method body.</param>
/// <param name="instanceField">The static field that holds the singleton instance.</param>
/// <returns>The singleton type's GetInstance method.</returns>
private MethodDefinition DefineGetInstance(TypeDefinition singletonType, ILProcessor il, FieldDefinition instanceField)
{
// Define the GetInstance method on the singleton type
var getInstanceMethodAttributes = MethodAttributes.Public | MethodAttributes.Static | MethodAttributes.HideBySig;
var getInstanceMethod = singletonType.DefineMethod("GetInstance", getInstanceMethodAttributes, typeof(object), new System.Type[0], new System.Type[0]);
var singletonWorker = getInstanceMethod.GetILGenerator();
singletonWorker.Emit(OpCodes.Ldsfld, instanceField);
singletonWorker.Emit(OpCodes.Ret);
return getInstanceMethod;
}
