Harmony12Interop/Harmony12Interop/Tools/PatchTools.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;

namespace Harmony
{
	public static class PatchTools
	{
		public static MethodInfo GetPatchMethod<T>(Type patchType, string name, Type[] parameters = null)
		{
			var method = patchType.GetMethods(AccessTools.all)
				.FirstOrDefault(m => m.GetCustomAttributes(typeof(T), true).Any());
			if (method == null)
				method = AccessTools.Method(patchType, name, parameters);
			return method;
		}

		public static void GetPatches(Type patchType, out MethodInfo prefix, out MethodInfo postfix, out MethodInfo transpiler)
		{
			prefix = GetPatchMethod<HarmonyPrefix>(patchType, "Prefix");
			postfix = GetPatchMethod<HarmonyPostfix>(patchType, "Postfix");
			transpiler = GetPatchMethod<HarmonyTranspiler>(patchType, "Transpiler");
		}
	}
}