move proxying to a separate NuGet library

1 files changed, 0 insertions, 405 deletions

diff --git a/src/SMAPI/Framework/Reflection/InterfaceProxyBuilder.cs b/src/SMAPI/Framework/Reflection/InterfaceProxyBuilder.cs
deleted file mode 100644
index 81cfff50..00000000
--- a/src/SMAPI/Framework/Reflection/InterfaceProxyBuilder.cs
+++ /dev/null
@@ -1,405 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Reflection;
-using System.Reflection.Emit;
-using System.Runtime.CompilerServices;
-
-namespace StardewModdingAPI.Framework.Reflection
-{
-    /// <summary>Generates a proxy class to access a mod API through an arbitrary interface.</summary>
-    internal class InterfaceProxyBuilder
-    {
-        /*********
-        ** Consts
-        *********/
-        private static readonly string TargetFieldName = "__Target";
-        private static readonly string GlueFieldName = "__Glue";
-        private static readonly MethodInfo ObtainInstanceForProxyTypeNameMethod = typeof(InterfaceProxyGlue).GetMethod(nameof(InterfaceProxyGlue.ObtainInstanceForProxyTypeName), new Type[] { typeof(string), typeof(object) });
-        private static readonly MethodInfo UnproxyOrObtainInstanceForProxyTypeNameMethod = typeof(InterfaceProxyGlue).GetMethod(nameof(InterfaceProxyGlue.UnproxyOrObtainInstanceForProxyTypeName), new Type[] { typeof(string), typeof(string), typeof(object) });
-
-        /*********
-        ** Fields
-        *********/
-        /// <summary>The target class type.</summary>
-        private readonly Type TargetType;
-
-        /// <summary>The interfce type.</summary>
-        private readonly Type InterfaceType;
-
-        /// <summary>The full name of the generated proxy type.</summary>
-        private readonly string ProxyTypeName;
-
-        /// <summary>The generated proxy type.</summary>
-        private Type ProxyType;
-
-        /// <summary>A cache of all proxies generated by this builder.</summary>
-        private readonly ConditionalWeakTable<object, object> ProxyCache = new();
-
-        /*********
-        ** Public methods
-        *********/
-        /// <summary>Construct an instance.</summary>
-        /// <param name="targetType">The target type.</param>
-        /// <param name="interfaceType">The interface type to implement.</param>
-        /// <param name="proxyTypeName">The type name to generate.</param>
-        public InterfaceProxyBuilder(Type targetType, Type interfaceType, string proxyTypeName)
-        {
-            // validate and store
-            this.TargetType = targetType ?? throw new ArgumentNullException(nameof(targetType));
-            this.InterfaceType = interfaceType ?? throw new ArgumentNullException(nameof(interfaceType));
-            this.ProxyTypeName = proxyTypeName ?? throw new ArgumentNullException(nameof(proxyTypeName));
-            if (!interfaceType.IsInterface)
-                throw new ArgumentException($"{nameof(interfaceType)} is not an interface.");
-        }
-
-
-        /// <summary>Creates and sets up the proxy type.</summary>
-        /// <param name="factory">The <see cref="InterfaceProxyFactory"/> that requested to build a proxy.</param>
-        /// <param name="moduleBuilder">The CLR module in which to create proxy classes.</param>
-        /// <param name="sourceModID">The unique ID of the mod consuming the API.</param>
-        /// <param name="targetModID">The unique ID of the mod providing the API.</param>
-        public void SetupProxyType(InterfaceProxyFactory factory, ModuleBuilder moduleBuilder, string sourceModID, string targetModID)
-        {
-            // define proxy type
-            TypeBuilder proxyBuilder = moduleBuilder.DefineType(this.ProxyTypeName, TypeAttributes.Public | TypeAttributes.Class);
-            proxyBuilder.AddInterfaceImplementation(this.InterfaceType);
-
-            // create fields to store target instance and proxy factory
-            FieldBuilder targetField = proxyBuilder.DefineField(TargetFieldName, this.TargetType, FieldAttributes.Private);
-            FieldBuilder glueField = proxyBuilder.DefineField(GlueFieldName, typeof(InterfaceProxyGlue), FieldAttributes.Private);
-
-            // create constructor which accepts target instance + factory, and sets fields
-            {
-                ConstructorBuilder constructor = proxyBuilder.DefineConstructor(MethodAttributes.Public, CallingConventions.Standard | CallingConventions.HasThis, new[] { this.TargetType, typeof(InterfaceProxyGlue) });
-                ILGenerator il = constructor.GetILGenerator();
-
-                il.Emit(OpCodes.Ldarg_0); // this
-                // ReSharper disable once AssignNullToNotNullAttribute -- never null
-                il.Emit(OpCodes.Call, typeof(object).GetConstructor(Array.Empty<Type>())); // call base constructor
-                il.Emit(OpCodes.Ldarg_0);      // this
-                il.Emit(OpCodes.Ldarg_1);      // load argument
-                il.Emit(OpCodes.Stfld, targetField); // set field to loaded argument
-                il.Emit(OpCodes.Ldarg_0);      // this
-                il.Emit(OpCodes.Ldarg_2);      // load argument
-                il.Emit(OpCodes.Stfld, glueField); // set field to loaded argument
-                il.Emit(OpCodes.Ret);
-            }
-
-            var allTargetMethods = this.TargetType.GetMethods().ToList();
-            foreach (Type targetInterface in this.TargetType.GetInterfaces())
-            {
-                foreach (MethodInfo targetMethod in targetInterface.GetMethods())
-                {
-                    if (!targetMethod.IsAbstract)
-                        allTargetMethods.Add(targetMethod);
-                }
-            }
-
-            MatchingTypesResult AreTypesMatching(Type targetType, Type proxyType, MethodTypeMatchingPart part)
-            {
-                var typeA = part == MethodTypeMatchingPart.Parameter ? targetType : proxyType;
-                var typeB = part == MethodTypeMatchingPart.Parameter ? proxyType : targetType;
-
-                if (typeA.IsGenericMethodParameter != typeB.IsGenericMethodParameter)
-                    return MatchingTypesResult.False;
-                // TODO: decide if "assignable" checking is desired (instead of just 1:1 type equality)
-                if (typeA.IsGenericMethodParameter ? typeA.GenericParameterPosition == typeB.GenericParameterPosition : typeA.IsAssignableFrom(typeB))
-                    return MatchingTypesResult.True;
-
-                if (!proxyType.IsGenericMethodParameter)
-                {
-                    if (proxyType.GetNonRefType().IsInterface)
-                        return MatchingTypesResult.IfProxied;
-                    if (targetType.GetNonRefType().IsInterface)
-                        return MatchingTypesResult.IfProxied;
-                }
-
-                return MatchingTypesResult.False;
-            }
-
-            // proxy methods
-            foreach (MethodInfo proxyMethod in this.InterfaceType.GetMethods())
-            {
-                var proxyMethodParameters = proxyMethod.GetParameters();
-                var proxyMethodGenericArguments = proxyMethod.GetGenericArguments();
-
-                foreach (MethodInfo targetMethod in allTargetMethods)
-                {
-                    // checking if `targetMethod` matches `proxyMethod`
-
-                    if (targetMethod.Name != proxyMethod.Name)
-                        continue;
-                    if (targetMethod.GetGenericArguments().Length != proxyMethodGenericArguments.Length)
-                        continue;
-                    var positionsToProxy = new HashSet<int?>(); // null = return type; anything else = parameter position
-
-                    switch (AreTypesMatching(targetMethod.ReturnType, proxyMethod.ReturnType, MethodTypeMatchingPart.ReturnType))
-                    {
-                        case MatchingTypesResult.False:
-                            continue;
-                        case MatchingTypesResult.True:
-                            break;
-                        case MatchingTypesResult.IfProxied:
-                            positionsToProxy.Add(null);
-                            break;
-                    }
-
-                    var mParameters = targetMethod.GetParameters();
-                    if (mParameters.Length != proxyMethodParameters.Length)
-                        continue;
-                    for (int i = 0; i < mParameters.Length; i++)
-                    {
-                        switch (AreTypesMatching(mParameters[i].ParameterType, proxyMethodParameters[i].ParameterType, MethodTypeMatchingPart.Parameter))
-                        {
-                            case MatchingTypesResult.False:
-                                goto targetMethodLoopContinue;
-                            case MatchingTypesResult.True:
-                                break;
-                            case MatchingTypesResult.IfProxied:
-                                positionsToProxy.Add(i);
-                                break;
-                        }
-                    }
-
-                    // method matched; proxying
-
-                    this.ProxyMethod(factory, proxyBuilder, proxyMethod, targetMethod, targetField, glueField, positionsToProxy, sourceModID, targetModID);
-                    goto proxyMethodLoopContinue;
-                    targetMethodLoopContinue:;
-                }
-
-                throw new InvalidOperationException($"The {this.InterfaceType.FullName} interface defines method {proxyMethod.Name} which doesn't exist in the API.");
-                proxyMethodLoopContinue:;
-            }
-
-            // save info
-            this.ProxyType = proxyBuilder.CreateType();
-        }
-
-        /// <summary>Get an existing or create a new instance of the proxy for a target instance.</summary>
-        /// <param name="targetInstance">The target instance.</param>
-        /// <param name="factory">The <see cref="InterfaceProxyFactory"/> that requested to build a proxy.</param>
-        public object ObtainInstance(object targetInstance, InterfaceProxyFactory factory)
-        {
-            if (this.ProxyCache.TryGetValue(targetInstance, out object proxyInstance))
-                return proxyInstance;
-
-            ConstructorInfo constructor = this.ProxyType.GetConstructor(new[] { this.TargetType, typeof(InterfaceProxyGlue) });
-            if (constructor == null)
-                throw new InvalidOperationException($"Couldn't find the constructor for generated proxy type '{this.ProxyType.Name}'."); // should never happen
-            proxyInstance = constructor.Invoke(new[] { targetInstance, new InterfaceProxyGlue(factory) });
-            this.ProxyCache.Add(targetInstance, proxyInstance);
-            return proxyInstance;
-        }
-
-
-        /*********
-        ** Private methods
-        *********/
-        /// <summary>Define a method which proxies access to a method on the target.</summary>
-        /// <param name="factory">The <see cref="InterfaceProxyFactory"/> that requested to build a proxy.</param>
-        /// <param name="proxyBuilder">The proxy type being generated.</param>
-        /// <param name="proxy">The proxy method.</param>
-        /// <param name="target">The target method.</param>
-        /// <param name="instanceField">The proxy field containing the API instance.</param>
-        /// <param name="glueField">The proxy field containing an <see cref="InterfaceProxyGlue"/>.</param>
-        /// <param name="positionsToProxy">Parameter type positions (or null for the return type) for which types should also be proxied.</param>
-        /// <param name="sourceModID">The unique ID of the mod consuming the API.</param>
-        /// <param name="targetModID">The unique ID of the mod providing the API.</param>
-        private void ProxyMethod(InterfaceProxyFactory factory, TypeBuilder proxyBuilder, MethodInfo proxy, MethodInfo target, FieldBuilder instanceField, FieldBuilder glueField, ISet<int?> positionsToProxy, string sourceModID, string targetModID)
-        {
-            MethodBuilder methodBuilder = proxyBuilder.DefineMethod(proxy.Name, MethodAttributes.Public | MethodAttributes.Final | MethodAttributes.Virtual);
-
-            // set up generic arguments
-            Type[] proxyGenericArguments = proxy.GetGenericArguments();
-            string[] genericArgNames = proxyGenericArguments.Select(a => a.Name).ToArray();
-            GenericTypeParameterBuilder[] genericTypeParameterBuilders = proxyGenericArguments.Length == 0 ? null : methodBuilder.DefineGenericParameters(genericArgNames);
-            for (int i = 0; i < proxyGenericArguments.Length; i++)
-                genericTypeParameterBuilders[i].SetGenericParameterAttributes(proxyGenericArguments[i].GenericParameterAttributes);
-
-            // set up return type
-            Type returnType = proxy.ReturnType.IsGenericMethodParameter ? genericTypeParameterBuilders[proxy.ReturnType.GenericParameterPosition] : proxy.ReturnType;
-            methodBuilder.SetReturnType(returnType);
-
-            // set up parameters
-            var targetParameters = target.GetParameters();
-            Type[] argTypes = proxy.GetParameters()
-                .Select(a => a.ParameterType)
-                .Select(t => t.IsGenericMethodParameter ? genericTypeParameterBuilders[t.GenericParameterPosition] : t)
-                .ToArray();
-
-            // proxy additional types
-            string returnValueProxyTypeName = null;
-            string[] parameterTargetToArgProxyTypeNames = new string[argTypes.Length];
-            string[] parameterArgToTargetUnproxyTypeNames = new string[argTypes.Length];
-            if (positionsToProxy.Count > 0)
-            {
-                foreach (int? position in positionsToProxy)
-                {
-                    // we don't check for generics here, because earlier code does and generic positions won't end up here
-                    if (position == null) // it's the return type
-                    {
-                        var builder = factory.ObtainBuilder(target.ReturnType, proxy.ReturnType, sourceModID, targetModID);
-                        returnType = proxy.ReturnType;
-                        returnValueProxyTypeName = builder.ProxyTypeName;
-                    }
-                    else // it's one of the parameters
-                    {
-                        bool isByRef = argTypes[position.Value].IsByRef;
-                        var targetType = targetParameters[position.Value].ParameterType;
-                        var argType = argTypes[position.Value];
-
-                        var builder = factory.ObtainBuilder(targetType.GetNonRefType(), argType.GetNonRefType(), sourceModID, targetModID);
-                        argTypes[position.Value] = argType;
-                        parameterTargetToArgProxyTypeNames[position.Value] = builder.ProxyTypeName;
-
-                        if (!targetParameters[position.Value].IsOut)
-                        {
-                            var argToTargetBuilder = factory.ObtainBuilder(argType.GetNonRefType(), targetType.GetNonRefType(), sourceModID, targetModID);
-                            parameterArgToTargetUnproxyTypeNames[position.Value] = argToTargetBuilder.ProxyTypeName;
-                        }
-                    }
-                }
-
-                methodBuilder.SetReturnType(returnType);
-            }
-
-            methodBuilder.SetParameters(argTypes);
-            for (int i = 0; i < argTypes.Length; i++)
-                methodBuilder.DefineParameter(i, targetParameters[i].Attributes, targetParameters[i].Name);
-
-            // create method body
-            {
-                ILGenerator il = methodBuilder.GetILGenerator();
-                LocalBuilder[] inputLocals = new LocalBuilder[argTypes.Length];
-                LocalBuilder[] outputLocals = new LocalBuilder[argTypes.Length];
-
-                void ProxyIfNeededAndStore(LocalBuilder inputLocal, LocalBuilder outputLocal, string proxyTypeName, string unproxyTypeName)
-                {
-                    if (proxyTypeName == null)
-                    {
-                        il.Emit(OpCodes.Ldloc, inputLocal);
-                        il.Emit(OpCodes.Stloc, outputLocal);
-                        return;
-                    }
-
-                    var isNullLabel = il.DefineLabel();
-                    il.Emit(OpCodes.Ldloc, inputLocal);
-                    il.Emit(OpCodes.Brfalse, isNullLabel);
-
-                    il.Emit(OpCodes.Ldarg_0);
-                    il.Emit(OpCodes.Ldfld, glueField);
-                    if (unproxyTypeName == null)
-                    {
-                        il.Emit(OpCodes.Ldstr, proxyTypeName);
-                        il.Emit(OpCodes.Ldloc, inputLocal);
-                        il.Emit(OpCodes.Call, ObtainInstanceForProxyTypeNameMethod);
-                    }
-                    else
-                    {
-                        il.Emit(OpCodes.Ldstr, proxyTypeName);
-                        il.Emit(OpCodes.Ldstr, unproxyTypeName);
-                        il.Emit(OpCodes.Ldloc, inputLocal);
-                        il.Emit(OpCodes.Call, UnproxyOrObtainInstanceForProxyTypeNameMethod);
-                    }
-                    il.Emit(OpCodes.Castclass, outputLocal.LocalType);
-                    il.Emit(OpCodes.Stloc, outputLocal);
-
-                    il.MarkLabel(isNullLabel);
-                }
-
-                // calling the proxied method
-                LocalBuilder resultInputLocal = target.ReturnType == typeof(void) ? null : il.DeclareLocal(target.ReturnType);
-                LocalBuilder resultOutputLocal = returnType == typeof(void) ? null : il.DeclareLocal(returnType);
-                il.Emit(OpCodes.Ldarg_0);
-                il.Emit(OpCodes.Ldfld, instanceField);
-                for (int i = 0; i < argTypes.Length; i++)
-                {
-                    if (targetParameters[i].IsOut && parameterTargetToArgProxyTypeNames[i] != null) // out parameter, proxy on the way back
-                    {
-                        inputLocals[i] = il.DeclareLocal(targetParameters[i].ParameterType.GetNonRefType());
-                        outputLocals[i] = il.DeclareLocal(argTypes[i].GetNonRefType());
-                        il.Emit(OpCodes.Ldloca, inputLocals[i]);
-                    }
-                    else if (parameterArgToTargetUnproxyTypeNames[i] != null) // normal parameter, proxy on the way in
-                    {
-                        inputLocals[i] = il.DeclareLocal(argTypes[i].GetNonRefType());
-                        outputLocals[i] = il.DeclareLocal(targetParameters[i].ParameterType.GetNonRefType());
-                        il.Emit(OpCodes.Ldarg, i + 1);
-                        il.Emit(OpCodes.Stloc, inputLocals[i]);
-                        ProxyIfNeededAndStore(inputLocals[i], outputLocals[i], parameterArgToTargetUnproxyTypeNames[i], parameterTargetToArgProxyTypeNames[i]);
-                        il.Emit(OpCodes.Ldloc, outputLocals[i]);
-                    }
-                    else // normal parameter, no proxying
-                    {
-                        il.Emit(OpCodes.Ldarg, i + 1);
-                    }
-                }
-                il.Emit(target.IsVirtual ? OpCodes.Callvirt : OpCodes.Call, target);
-                if (target.ReturnType != typeof(void))
-                    il.Emit(OpCodes.Stloc, resultInputLocal);
-
-                // proxying `out` parameters
-                for (int i = 0; i < argTypes.Length; i++)
-                {
-                    if (parameterTargetToArgProxyTypeNames[i] == null)
-                        continue;
-                    if (!targetParameters[i].IsOut)
-                        continue;
-
-                    ProxyIfNeededAndStore(inputLocals[i], outputLocals[i], parameterTargetToArgProxyTypeNames[i], null);
-                    il.Emit(OpCodes.Ldarg, i + 1);
-                    il.Emit(OpCodes.Ldloc, outputLocals[i]);
-                    il.Emit(OpCodes.Stind_Ref);
-                }
-
-                // proxying return value
-                if (target.ReturnType != typeof(void))
-                    ProxyIfNeededAndStore(resultInputLocal, resultOutputLocal, returnValueProxyTypeName, null);
-
-                // return result
-                if (target.ReturnType != typeof(void))
-                    il.Emit(OpCodes.Ldloc, resultOutputLocal);
-                il.Emit(OpCodes.Ret);
-            }
-        }
-
-        /// <summary>Try to get a target instance for a given proxy instance.</summary>
-        /// <param name="potentialProxyInstance">The proxy instance to look for.</param>
-        /// <param name="targetInstance">The reference to store the found target instance in.</param>
-        public bool TryUnproxy(object potentialProxyInstance, out object targetInstance)
-        {
-            foreach ((object cachedTargetInstance, object cachedProxyInstance) in this.ProxyCache)
-            {
-                if (object.ReferenceEquals(potentialProxyInstance, cachedProxyInstance))
-                {
-                    targetInstance = cachedTargetInstance;
-                    return true;
-                }
-            }
-            targetInstance = null;
-            return false;
-        }
-
-        /// <summary>The part of a method that is being matched.</summary>
-        private enum MethodTypeMatchingPart
-        {
-            ReturnType, Parameter
-        }
-
-        /// <summary>The result of matching a target and a proxy type.</summary>
-        private enum MatchingTypesResult
-        {
-            False, IfProxied, True
-        }
-    }
-
-    internal static class TypeExtensions
-    {
-        internal static Type GetNonRefType(this Type type)
-        {
-            return type.IsByRef ? type.GetElementType() : type;
-        }
-    }
-}