Add AutoPatch Harmony attribute

Author: MrBlue

src/Oxide.Core.csproj

@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <Project>
   <Import Project="Sdk.props" Sdk="Microsoft.NET.Sdk" />
   <Import Project="..\netfx.props" />
@@ -17,6 +17,7 @@
     <NoWarn>NU1701</NoWarn>
   </PropertyGroup>
   <ItemGroup>
+    <PackageReference Include="Lib.Harmony" Version="2.3.3" />
     <PackageReference Include="Oxide.Common" Version="2.0.21-develop" />
     <PackageReference Include="Oxide.References" Version="2.0.*">
       <PrivateAssets>contentfiles;analyzers;build</PrivateAssets>

src/Plugins/CSPlugin.cs

@@ -3,6 +3,7 @@
 using System.Collections.Generic;
 using System.Reflection;
 using Oxide.Pooling;
+using HarmonyLib;
 
 namespace Oxide.Core.Plugins
 {
@@ -27,6 +28,17 @@ public HookMethodAttribute(string name)
         }
     }
 
+    /// <summary>
+    /// Indicates that the specified class should automatically apply it's harmony patches
+    /// </summary>
+    [AttributeUsage(AttributeTargets.Class)]
+    public class AutoPatchAttribute : Attribute
+    {
+        public AutoPatchAttribute()
+        {
+        }
+    }
+
     /// <summary>
     /// Represents a plugin implemented in .NET
     /// </summary>
@@ -42,6 +54,22 @@ public abstract class CSPlugin : Plugin
         // All hooked methods
         protected Dictionary<string, List<HookMethod>> Hooks = new Dictionary<string, List<HookMethod>>();
 
+        // Harmony
+        private Harmony _harmonyInstance;
+        protected string HarmonyId => $"com.oxidemod.{Name}";
+        protected Harmony HarmonyInstance
+        {
+            get
+            {
+                if (_harmonyInstance == null)
+                {
+                    _harmonyInstance = new Harmony(HarmonyId);
+                }
+
+                return _harmonyInstance;
+            }
+        }
+
         // All matched hooked methods
         protected HookCache HooksCache = new HookCache();
 
@@ -97,6 +125,29 @@ public override void HandleAddedToManager(PluginManager manager)
                 Subscribe(hookname);
             }
 
+            // Find all classes with the AutoPatch attribute and apply the patches
+            foreach (Type nestedType in GetType().GetNestedTypes(BindingFlags.DeclaredOnly | BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Static))
+            {
+                object[] attr = nestedType.GetCustomAttributes(typeof(AutoPatchAttribute), false);
+                if (attr.Length < 1)
+                {
+                    continue;
+                }
+
+                List<MethodInfo> harmonyMethods = HarmonyInstance.CreateClassProcessor(nestedType)?.Patch();
+
+                if (harmonyMethods == null || harmonyMethods.Count == 0)
+                {
+                    Interface.Oxide.LogWarning($"[{Title}] AutoPatch attribute found on '{nestedType.Name}' but no HarmonyPatch methods found. Skipping.");
+                    continue;
+                }
+
+                foreach (MethodInfo method in harmonyMethods)
+                {
+                    Interface.Oxide.LogInfo($"[{Title}] Automatically Harmony patched '{method.Name}' method. ({nestedType.Name})");
+                }
+            }
+
             try
             {
                 // Let the plugin know that it is loading
@@ -112,6 +163,19 @@ public override void HandleAddedToManager(PluginManager manager)
             }
         }
 
+        /// <summary>
+        /// Called when this plugin has been removed from a manager
+        /// </summary>
+        /// <param name="manager"></param>
+        public override void HandleRemovedFromManager(PluginManager manager)
+        {
+            // Unpatch all automatically patched Harmony patches
+            _harmonyInstance?.UnpatchAll(HarmonyId);
+
+            // Let base work
+            base.HandleRemovedFromManager(manager);
+        }
+
         protected void AddHookMethod(string name, MethodInfo method)
         {
             if (!Hooks.TryGetValue(name, out List<HookMethod> hookMethods))