private static Type EnsureDelegateType(BuildContext context, MethodInfo method)
{
// The delegate should be defined as inner type of context.TypeBuilder.
// It's possible, but we can not define and use newly defined type as Emit target in its owner type.
// To solve this problem, we should create a top level delegate and make sure its name is unique.
//
string delegateName = context.TypeBuilder.TypeBuilder.FullName + "$" + method.Name + "$Delegate";
Type delegateType = (Type)context.Items[delegateName];
if (delegateType == null)
{
ParameterInfo[] pi = method.GetParameters();
Type[] parameters = new Type[pi.Length];
for (int i = 0; i < pi.Length; i++)
{
parameters[i] = pi[i].ParameterType;
}
const MethodImplAttributes mia = MethodImplAttributes.Runtime | MethodImplAttributes.Managed;
const MethodAttributes ma = MethodAttributes.Public | MethodAttributes.HideBySig | MethodAttributes.NewSlot | MethodAttributes.Virtual;
TypeBuilderHelper delegateBuilder = context.AssemblyBuilder.DefineType(delegateName,
TypeAttributes.Class | TypeAttributes.NotPublic | TypeAttributes.Sealed | TypeAttributes.AnsiClass | TypeAttributes.AutoClass,
typeof(MulticastDelegate));
// Create constructor
//
ConstructorBuilderHelper ctorBuilder = delegateBuilder.DefineConstructor(
MethodAttributes.Public | MethodAttributes.HideBySig | MethodAttributes.RTSpecialName, CallingConventions.Standard,
typeof(object), typeof(IntPtr));
ctorBuilder.ConstructorBuilder.SetImplementationFlags(mia);
MethodBuilderHelper methodBuilder;
// Define the BeginInvoke method for the delegate
//
Type[] beginParameters = new Type[parameters.Length + 2];
Array.Copy(parameters, 0, beginParameters, 0, parameters.Length);
beginParameters[parameters.Length] = typeof(AsyncCallback);
beginParameters[parameters.Length + 1] = typeof(object);
methodBuilder = delegateBuilder.DefineMethod("BeginInvoke", ma, typeof(IAsyncResult), beginParameters);
methodBuilder.MethodBuilder.SetImplementationFlags(mia);
// Define the EndInvoke method for the delegate
//
methodBuilder = delegateBuilder.DefineMethod("EndInvoke", ma, method.ReturnType, typeof(IAsyncResult));
methodBuilder.MethodBuilder.SetImplementationFlags(mia);
// Define the Invoke method for the delegate
//
methodBuilder = delegateBuilder.DefineMethod("Invoke", ma, method.ReturnType, parameters);
methodBuilder.MethodBuilder.SetImplementationFlags(mia);
context.Items[delegateName] = delegateType = delegateBuilder.Create();
}
return(delegateType);
}
