Re-implement TypeReader override liogic

src/Discord.Net.Commands/Attributes/TypeReaderAttribute.cs

@@ -0,0 +1,21 @@
+using System;
+using System.Reflection;
+
+namespace Discord.Commands.Attributes
+{
+    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Parameter, AllowMultiple = true)]
+    public class TypeReaderAttribute : Attribute
+    {
+        public Type Type { get; }
+        public TypeInfo OverridingTypeReader { get; }
+
+        public TypeReaderAttribute(Type forType, Type typeReader)
+        {
+            if (!typeof(TypeReader).GetTypeInfo().IsAssignableFrom(typeReader.GetTypeInfo()))
+                throw new ArgumentException($"Type of argument {nameof(typeReader)} must derive from {nameof(TypeReader)}", nameof(typeReader));
+
+            Type = forType;
+            OverridingTypeReader = typeReader.GetTypeInfo();
+        }
+    }
+}

src/Discord.Net.Commands/CommandInfo.cs

@@ -6,6 +6,7 @@ using System.Diagnostics;
 using System.Linq;
 using System.Reflection;
 using System.Threading.Tasks;
+using Discord.Commands.Attributes;
 
 namespace Discord.Commands
 {
@@ -30,7 +31,7 @@ namespace Discord.Commands
         public IReadOnlyList<CommandParameter> Parameters { get; }
         public IReadOnlyList<PreconditionAttribute> Preconditions { get; }
 
-        internal CommandInfo(MethodInfo source, ModuleInfo module, CommandAttribute attribute, string groupPrefix)
+        internal CommandInfo(MethodInfo source, ModuleInfo module, CommandAttribute attribute, string groupPrefix, IDependencyMap dependencyMap = null)
         {
             try
             {
@@ -74,7 +75,7 @@ namespace Discord.Commands
                 var priorityAttr = source.GetCustomAttribute<PriorityAttribute>();
                 Priority = priorityAttr?.Priority ?? 0;
 
-                Parameters = BuildParameters(source);
+                Parameters = BuildParameters(source, dependencyMap);
                 HasVarArgs = Parameters.Count > 0 ? Parameters[Parameters.Count - 1].IsMultiple : false;
                 Preconditions = BuildPreconditions(source);
                 _action = BuildAction(source);
@@ -184,7 +185,7 @@ namespace Discord.Commands
             return methodInfo.GetCustomAttributes<PreconditionAttribute>().ToImmutableArray();
         }
 
-        private IReadOnlyList<CommandParameter> BuildParameters(MethodInfo methodInfo)
+        private IReadOnlyList<CommandParameter> BuildParameters(MethodInfo methodInfo, IDependencyMap dependencyMap = null)
         {
             var parameters = methodInfo.GetParameters();
 
@@ -199,7 +200,13 @@ namespace Discord.Commands
                 if (isMultiple)
                     type = type.GetElementType();
 
-                var reader = Module.Service.GetTypeReader(type);
+                var trAttr = parameter.GetCustomAttribute<TypeReaderAttribute>();
+
+                var reader = (trAttr != null && trAttr.Type == type) ?
+                    ReflectionUtils.CreateObject<TypeReader>(trAttr.OverridingTypeReader, Module.Service, dependencyMap) :
+                    (Module.OverridingTypeReaders.ContainsKey(type) ?
+                        Module.OverridingTypeReaders[type] :
+                        Module.Service.GetTypeReader(type));
                 var typeInfo = type.GetTypeInfo();
 
                 //Detect enums

src/Discord.Net.Commands/CommandService.cs

@@ -65,7 +65,7 @@ namespace Discord.Commands
         }
 
         //Modules
-        public async Task<ModuleInfo> AddModule<T>()
+        public async Task<ModuleInfo> AddModule<T>(IDependencyMap dependencyMap = null)
         {
             await _moduleLock.WaitAsync().ConfigureAwait(false);
             try
@@ -80,14 +80,14 @@ namespace Discord.Commands
                 if (_moduleDefs.ContainsKey(typeof(T)))
                     throw new ArgumentException($"This module has already been added.");
 
-                return AddModuleInternal(typeInfo);
+                return AddModuleInternal(typeInfo, dependencyMap);
             }
             finally
             {
                 _moduleLock.Release();
             }
         }
-        public async Task<IEnumerable<ModuleInfo>> AddModules(Assembly assembly)
+        public async Task<IEnumerable<ModuleInfo>> AddModules(Assembly assembly, IDependencyMap dependencyMap = null)
         {
             var moduleDefs = ImmutableArray.CreateBuilder<ModuleInfo>();
             await _moduleLock.WaitAsync().ConfigureAwait(false);
@@ -102,7 +102,7 @@ namespace Discord.Commands
                         {
                             var dontAutoLoad = typeInfo.GetCustomAttribute<DontAutoLoadAttribute>();
                             if (dontAutoLoad == null && !typeInfo.IsAbstract)
-                                moduleDefs.Add(AddModuleInternal(typeInfo));
+                                moduleDefs.Add(AddModuleInternal(typeInfo, dependencyMap));
                         }
                     }
                 }
@@ -113,9 +113,9 @@ namespace Discord.Commands
                 _moduleLock.Release();
             }
         }
-        private ModuleInfo AddModuleInternal(TypeInfo typeInfo)
+        private ModuleInfo AddModuleInternal(TypeInfo typeInfo, IDependencyMap dependencyMap = null)
         {
-            var moduleDef = new ModuleInfo(typeInfo, this);
+            var moduleDef = new ModuleInfo(typeInfo, this, dependencyMap);
             _moduleDefs[typeInfo.AsType()] = moduleDef;
 
             foreach (var cmd in moduleDef.Commands)

src/Discord.Net.Commands/ModuleInfo.cs

@@ -3,6 +3,7 @@ using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Diagnostics;
 using System.Reflection;
+using Discord.Commands.Attributes;
 
 namespace Discord.Commands
 {
@@ -19,8 +20,9 @@ namespace Discord.Commands
         public string Remarks { get; }
         public IEnumerable<CommandInfo> Commands { get; }
         public IReadOnlyList<PreconditionAttribute> Preconditions { get; }
+        public ImmutableDictionary<Type, TypeReader> OverridingTypeReaders { get; }
 
-        internal ModuleInfo(TypeInfo source, CommandService service)
+        internal ModuleInfo(TypeInfo source, CommandService service, IDependencyMap dependencyMap = null)
         {
             Source = source;
             Service = service;
@@ -45,19 +47,31 @@ namespace Discord.Commands
             if (remarksAttr != null)
                 Remarks = remarksAttr.Text;
 
+            var typeReaders = new Dictionary<Type, TypeReader>();
+
+            var trAttrs = source.GetCustomAttributes<TypeReaderAttribute>();
+            foreach (var trAttr in trAttrs)
+                typeReaders[trAttr.Type] = GetOverridingTypeReader(trAttr, dependencyMap);
+
+            OverridingTypeReaders = typeReaders.ToImmutableDictionary();
+
             List<CommandInfo> commands = new List<CommandInfo>();
-            SearchClass(source, commands, Prefix);
+            SearchClass(source, commands, Prefix, dependencyMap);
             Commands = commands;
 
             Preconditions = Source.GetCustomAttributes<PreconditionAttribute>().ToImmutableArray();
         }
-        private void SearchClass(TypeInfo parentType, List<CommandInfo> commands, string groupPrefix)
+
+        private TypeReader GetOverridingTypeReader(TypeReaderAttribute trAttr, IDependencyMap dependencyMap = null)
+            => ReflectionUtils.CreateObject<TypeReader>(trAttr.OverridingTypeReader, Service, dependencyMap);
+
+        private void SearchClass(TypeInfo parentType, List<CommandInfo> commands, string groupPrefix, IDependencyMap dependencyMap = null)
         {
             foreach (var method in parentType.DeclaredMethods)
             {
                 var cmdAttr = method.GetCustomAttribute<CommandAttribute>();
                 if (cmdAttr != null)
-                    commands.Add(new CommandInfo(method, this, cmdAttr, groupPrefix));
+                    commands.Add(new CommandInfo(method, this, cmdAttr, groupPrefix, dependencyMap));
             }
             foreach (var type in parentType.DeclaredNestedTypes)
             {
@@ -71,7 +85,7 @@ namespace Discord.Commands
                     else
                         nextGroupPrefix = groupAttrib.Prefix ?? type.Name.ToLowerInvariant();
 
-                    SearchClass(type, commands, nextGroupPrefix);
+                    SearchClass(type, commands, nextGroupPrefix, dependencyMap);
                 }
             }
         }