Applied Use of LinFu/Cecil and Aspect-Oriented Programming Concepts - A Library

using System;
using System.Reflection;
using System.Windows.Forms;

using System.Collections.Generic;
using System.IO;
using System.ComponentModel;
using System.Collections;
using System.Text;
using System.Threading;
using System.Runtime.Serialization.Formatters.Binary;

using BrainTechLLC.ThreadSafeObjects;
using LinFu.AOP;
using LinFu.AOP.Interfaces;

namespace BrainTechLLC
{
	[Serializable, AttributeUsage(AttributeTargets.Method)]
	public class InvokeIfThenElseAttribute : IfCaseAttribute, IReadableAttribute
	{
		public InvokeIfThenElseAttribute(string ifMethod, string thenMethod, string elseMethod,
			string ifMethodAfter, string thenMethodAfter, string elseMethodAfter)
			: base(ifMethod, thenMethod, elseMethod, ifMethodAfter, thenMethodAfter, elseMethodAfter) { }
	}

	[Serializable, AttributeUsage(AttributeTargets.Method)]
	public class IfCaseAttribute : Attribute, IReadableAttribute
	{
		public string IfMethodName { get; set; }
		public string ThenMethodName { get; set; }
		public string ElseMethodName { get; set; }
		public string IfMethodNameAfter { get; set; }
		public string ThenMethodNameAfter { get; set; }
		public string ElseMethodNameAfter { get; set; }

		public object Value { get { return IfMethodName; } }

		public IfCaseAttribute(string ifMethod, string thenMethod, string elseMethod,
			string ifMethodAfter, string thenMethodAfter, string elseMethodAfter)
		{
			IfMethodName = ifMethod;
			ThenMethodName = thenMethod;
			ElseMethodName = elseMethod;
			IfMethodNameAfter = ifMethodAfter;
			ThenMethodNameAfter = thenMethodAfter;
			ElseMethodNameAfter = elseMethodAfter;
		}

		protected void GetIfThenElseMethodsBefore(Type t, out MethodInfo ifDel, out MethodInfo thenDel, out MethodInfo elseDel)
		{
			ifDel = Lookups.IfLookup[t.Name + "." + IfMethodName];
			thenDel = null;
			elseDel = null;

			if (ifDel == null)
			{
				ifDel = t.GetMethod(IfMethodName);
				Lookups.IfLookup.AddOrSet(t.Name + "." + IfMethodName, ifDel);
			}

			if (!string.IsNullOrEmpty(ThenMethodName))
			{
				thenDel = Lookups.ThenLookup[t.Name + "." + ThenMethodName];

				if (thenDel == null)
				{
					thenDel = t.GetMethod(ThenMethodName);
					Lookups.ThenLookup.AddOrSet(t.Name + "." + ThenMethodName, thenDel);
				}
			}

			if (!string.IsNullOrEmpty(ElseMethodName))
			{
				elseDel = Lookups.ElseLookup[t.Name + "." + ElseMethodName];

				if (elseDel == null)
				{
					elseDel = t.GetMethod(ElseMethodName);
					Lookups.ElseLookup.AddOrSet(t.Name + "." + ElseMethodName, elseDel);
				}
			}
		}

		protected void GetIfThenElseMethodsAfter(Type t, out MethodInfo ifDel, out MethodInfo thenDel, out MethodInfo elseDel)
		{
			ifDel = Lookups.IfLookup[t.Name + "." + IfMethodNameAfter];
			thenDel = null;
			elseDel = null;

			if (!string.IsNullOrEmpty(ThenMethodNameAfter))
			{
				thenDel = Lookups.ThenLookup[t.Name + "." + ThenMethodNameAfter];

				if (thenDel == null)
				{
					thenDel = t.GetMethod(ThenMethodNameAfter);

					if (thenDel != null)
						Lookups.ThenLookup.AddOrSet(t.Name + "." + ThenMethodNameAfter, thenDel);
				}
			}

			if (!string.IsNullOrEmpty(ElseMethodNameAfter))
			{
				elseDel = Lookups.ElseLookup[t.Name + "." + ElseMethodNameAfter];

				if (elseDel == null)
				{
					elseDel = t.GetMethod(ElseMethodNameAfter);

					if (elseDel != null)
						Lookups.ElseLookup.AddOrSet(t.Name + "." + ElseMethodNameAfter, elseDel);
				}
			}

			if (ifDel == null)
			{
				ifDel = t.GetMethod(IfMethodNameAfter);

				if (ifDel != null)
					Lookups.IfLookup.AddOrSet(t.Name + "." + IfMethodNameAfter, ifDel);
			}
		}

		public void DoWorkBefore(IInvocationContext context, object thisObject)
		{
			Type t = thisObject.GetType();
			MethodInfo ifDel;
			MethodInfo thenDel;
			MethodInfo elseDel;
			GetIfThenElseMethodsBefore(t, out ifDel, out thenDel, out elseDel);

			if (ifDel == null)
			{
				if (thenDel != null)
					thenDel.Invoke(thisObject, new object[] { context });
			}
			else
			{
				object result = ifDel.Invoke(thisObject, new object[] { context });

				if (Convert.ToBoolean(result) == true)
				{
					if (thenDel != null)
						thenDel.Invoke(thisObject, new object[] { context });
				}
				else
				{
					if (elseDel != null)
						elseDel.Invoke(thisObject, new object[] { context });
				}
			}
		}

		public void DoWorkAfter(IInvocationContext context, object thisObject)
		{
			Type t = thisObject.GetType();
			MethodInfo ifDel;
			MethodInfo thenDel;
			MethodInfo elseDel;
			GetIfThenElseMethodsAfter(t, out ifDel, out thenDel, out elseDel);
			
			if (ifDel == null)
			{
				if (thenDel != null)
					thenDel.Invoke(thisObject, new object[] { context });
			}
			else
			{
				object result = ifDel.Invoke(thisObject, new object[] { context });

				if (Convert.ToBoolean(result) == true)
				{
					if (thenDel != null)
						thenDel.Invoke(thisObject, new object[] { context });
				}
				else
				{
					if (elseDel != null)
						elseDel.Invoke(thisObject, new object[] { context });
				}
			}
		}
	}
}