Fix issue with ABI delegates in collections for .NET Standard project…

…ion (#1330)

* Most of the changes to remove use of Expression.GetDelegateType for .NET standard projections

* Fix build

* Address issues to get test passing

* Fix tests

* Rearranage which files the delegates are generated in and scoping it to .NET Standard

* Add tests

* Enable test for Net Framework

* Scope delegates to NET Standard

* Update UnitTestEmbedded.csproj

* Handle edge case of generic type referencing another generic type.

* Minor clarifications

src/Samples/TestEmbedded/C++ Components/Alpha/Alpha.cpp

@@ -4,4 +4,24 @@
 
 namespace winrt::Alpha::implementation
 {
+    template <typename T, typename Allocator = std::allocator<T>>
+    Windows::Foundation::Collections::IVectorView<T> single_threaded_vector_view(std::vector<T, Allocator>&& values = {})
+    {
+        return make<impl::input_vector_view<T, std::vector<T, Allocator>>>(std::move(values));
+    }
+
+    winrt::Windows::Foundation::Collections::IVector<hstring> Class::GetStringList()
+    {
+        return winrt::single_threaded_vector<hstring>({ L"alpha", L"beta" });
+    }
+
+    winrt::Windows::Foundation::Collections::IVector<int> Class::GetIntList()
+    {
+        return winrt::single_threaded_vector<int>({ 4, 3, 2, 1 });
+    }
+
+    winrt::Windows::Foundation::Collections::IVectorView<winrt::Alpha::Class> Class::GetObjectList()
+    {
+        return single_threaded_vector_view<winrt::Alpha::Class>({ *this, *this });
+    }
 }

src/Samples/TestEmbedded/C++ Components/Alpha/Alpha.h

@@ -7,6 +7,10 @@ namespace winrt::Alpha::implementation
     struct Class : ClassT<Class>
     {
         Class() = default;
+
+        winrt::Windows::Foundation::Collections::IVector<hstring> GetStringList();
+        winrt::Windows::Foundation::Collections::IVector<int> GetIntList();
+        winrt::Windows::Foundation::Collections::IVectorView<winrt::Alpha::Class> GetObjectList();
     };
 }
 

src/Samples/TestEmbedded/C++ Components/Alpha/Alpha.idl

@@ -4,6 +4,10 @@ namespace Alpha
     runtimeclass Class
     {
         Class();
+
+        Windows.Foundation.Collections.IVector<String> GetStringList();
+        Windows.Foundation.Collections.IVector<Int32> GetIntList();
+        Windows.Foundation.Collections.IVectorView<Class> GetObjectList();
     }
 
     interface IAlpha

src/Samples/TestEmbedded/TestEmbeddedLibrary/TestLib.cs

@@ -69,6 +69,48 @@ public int Test5()
             {
                 return (int)abuff.Capacity;
             }
+        }
+
+        public int Test6()
+        {
+            Alpha.Class a = new();
+
+            int success = 0;
+            var stringList = a.GetStringList();
+            if (stringList.Count == 2)
+            {
+                success++;
+            }
+
+            if (stringList[0] == "alpha" && stringList[1] == "beta")
+            {
+                success++;
+            }
+
+            var intList = a.GetIntList();
+            if (intList.Count == 4)
+            {
+                success++;
+            }
+
+            int sum = 0;
+            foreach (var i in intList)
+            {
+                sum += i;
+            }
+
+            if (sum == 10)
+            {
+                success++;
+            }
+
+            var objList = a.GetObjectList();
+            if ((objList[0] == objList[1]))
+            {
+                success++;
+            }
+
+            return success;
         }
     }
 

src/Samples/TestEmbedded/UnitTestEmbedded/TestClass.cs

@@ -37,6 +37,12 @@ public void Test4()
         public void Test5()
         {
             Assert.Equal(20, TestLib.Test5());
+        }
+
+        [Fact]
+        public void Test6()
+        {
+            Assert.Equal(5, TestLib.Test6());
         }
     }
 }

src/Tests/UnitTest/TestModuleInitializer.cs

@@ -0,0 +1,40 @@
+using System;
+using WinRT;
+
+#if !NET
+
+namespace UnitTest
+{
+    // In our .NET standard support, we generate most of the delegates needed by generic types as part of the projection.  But for the ones
+    // passed or obtained as an Object, we are not able to statically detect that.  On .NET Core, we are able to utilize Expression.GetDelegateType
+    // to dynamically create one in this case, but on .NET Framework we are not able to do that for ones with pointers in their parameters.
+    // This tests that scenario where the ABI delegates need to be manually declared and registered by the caller.
+    internal static class ProjectionTypesInitializer
+    {
+        [System.Runtime.CompilerServices.ModuleInitializer]
+        internal static void InitalizeProjectionTypes()
+        {
+            Projections.RegisterAbiDelegate(new Type[] { typeof(void*), typeof(ABI.TestComponent.NonBlittable).MakeByRefType(), typeof(int) }, typeof(_get_Value_NonBlittable));
+            Projections.RegisterAbiDelegate(new Type[] { typeof(void*), typeof(TestComponentCSharp.EnumValue).MakeByRefType(), typeof(int) }, typeof(_get_Value_EnumValue));
+            Projections.RegisterAbiDelegate(new Type[] { typeof(void*), typeof(uint), typeof(ABI.TestComponent.Composable).MakeByRefType(), typeof(int) }, typeof(_get_at_Composable));
+            Projections.RegisterAbiDelegate(new Type[] { typeof(void*), typeof(ABI.TestComponent.Composable), typeof(uint).MakeByRefType(), typeof(byte).MakeByRefType(), typeof(int) }, typeof(_index_of_Composable));
+            Projections.RegisterAbiDelegate(new Type[] { typeof(void*), typeof(uint), typeof(ABI.TestComponent.Composable), typeof(int) }, typeof(_set_at_Composable));
+            Projections.RegisterAbiDelegate(new Type[] { typeof(void*), typeof(ABI.TestComponent.Composable), typeof(int) }, typeof(_append_Composable));
+        }
+
+        internal unsafe delegate int _get_Value_NonBlittable(void* thisPtr, out ABI.TestComponent.NonBlittable __return_value__);
+        internal unsafe delegate int _get_Value_EnumValue(void* thisPtr, out TestComponentCSharp.EnumValue __return_value__);
+        internal unsafe delegate int _get_at_Composable(void* thisPtr, uint index, out ABI.TestComponent.Composable __return_value__);
+        internal unsafe delegate int _index_of_Composable(void* thisPtr, ABI.TestComponent.Composable value, out uint index, out byte found);
+        internal unsafe delegate int _set_at_Composable(void* thisPtr, uint index, ABI.TestComponent.Composable value);
+        internal unsafe delegate int _append_Composable(void* thisPtr, ABI.TestComponent.Composable value);
+    }
+}
+
+namespace System.Runtime.CompilerServices
+{
+    [AttributeUsage(AttributeTargets.Method)]
+    internal sealed class ModuleInitializerAttribute : Attribute { }
+}
+
+#endif

src/WinRT.Runtime/FundamentalMarshalers.cs

@@ -7,28 +7,26 @@ namespace ABI.System
 {
     internal struct Boolean
     {
-        byte value;
         public static bool CreateMarshaler(bool value) => value;
-        public static Boolean GetAbi(bool value) => new Boolean() { value = (byte)(value ? 1 : 0) };
-        public static bool FromAbi(Boolean abi) => abi.value != 0;
-        public static unsafe void CopyAbi(bool value, IntPtr dest) => *(byte*)dest.ToPointer() = GetAbi(value).value;
-        public static Boolean FromManaged(bool value) => GetAbi(value);
-        public static unsafe void CopyManaged(bool arg, IntPtr dest) => *(byte*)dest.ToPointer() = FromManaged(arg).value;
+        public static byte GetAbi(bool value) => (byte)(value ? 1 : 0);
+        public static bool FromAbi(byte abi) => abi != 0;
+        public static unsafe void CopyAbi(bool value, IntPtr dest) => *(byte*)dest.ToPointer() = GetAbi(value);
+        public static byte FromManaged(bool value) => GetAbi(value);
+        public static unsafe void CopyManaged(bool arg, IntPtr dest) => *(byte*)dest.ToPointer() = FromManaged(arg);
         public static void DisposeMarshaler(bool m) { }
-        public static void DisposeAbi(Boolean abi) { }
+        public static void DisposeAbi(byte abi) { }
     }
 
     internal struct Char
     {
-        ushort value;
         public static char CreateMarshaler(char value) => value;
-        public static Char GetAbi(char value) => new Char() { value = (ushort)value };
-        public static char FromAbi(Char abi) => (char)abi.value;
-        public static unsafe void CopyAbi(char value, IntPtr dest) => *(ushort*)dest.ToPointer() = GetAbi(value).value;
-        public static Char FromManaged(char value) => GetAbi(value);
-        public static unsafe void CopyManaged(char arg, IntPtr dest) => *(ushort*)dest.ToPointer() = FromManaged(arg).value;
+        public static ushort GetAbi(char value) => (ushort)value;
+        public static char FromAbi(ushort abi) => (char)abi;
+        public static unsafe void CopyAbi(char value, IntPtr dest) => *(ushort*)dest.ToPointer() = GetAbi(value);
+        public static ushort FromManaged(char value) => GetAbi(value);
+        public static unsafe void CopyManaged(char arg, IntPtr dest) => *(ushort*)dest.ToPointer() = FromManaged(arg);
         public static void DisposeMarshaler(char m) { }
-        public static void DisposeAbi(Char abi) { }
+        public static void DisposeAbi(ushort abi) { }
     }
 }
 

src/WinRT.Runtime/Interop/StandardDelegates.cs

@@ -231,4 +231,34 @@ namespace WinRT.Interop
     public 
 #endif 
     delegate int _remove_EventHandler(IntPtr thisPtr, EventRegistrationToken token);
-}
+
+#if !NET
+    internal unsafe delegate int _get_Current_IntPtr(void* thisPtr, out IntPtr __return_value__);
+    internal unsafe delegate int _get_Current_Type(void* thisPtr, out ABI.System.Type __return_value__);
+
+    internal unsafe delegate int _get_At_IntPtr(void* thisPtr, uint index, out IntPtr __return_value__);
+    internal unsafe delegate int _get_At_Type(void* thisPtr, uint index, out ABI.System.Type __return_value__);
+    internal unsafe delegate int _index_Of_IntPtr(void* thisPtr, IntPtr value, out uint index, out byte found);
+    internal unsafe delegate int _index_Of_Type(void* thisPtr, ABI.System.Type value, out uint index, out byte found);
+    internal unsafe delegate int _set_At_IntPtr(void* thisPtr, uint index, IntPtr value);
+    internal unsafe delegate int _set_At_Type(void* thisPtr, uint index, ABI.System.Type value);
+    internal unsafe delegate int _append_IntPtr(void* thisPtr, IntPtr value);
+    internal unsafe delegate int _append_Type(void* thisPtr, ABI.System.Type value);
+
+    internal unsafe delegate int _lookup_IntPtr_IntPtr(void* thisPtr, IntPtr key, out IntPtr value);
+    internal unsafe delegate int _lookup_Type_Type(void* thisPtr, ABI.System.Type key, out ABI.System.Type value);
+    internal unsafe delegate int _lookup_IntPtr_Type(void* thisPtr, IntPtr key, out ABI.System.Type value);
+    internal unsafe delegate int _lookup_Type_IntPtr(void* thisPtr, ABI.System.Type key, out IntPtr value);
+    internal unsafe delegate int _has_key_IntPtr(void* thisPtr, IntPtr key, out byte found);
+    internal unsafe delegate int _has_key_Type(void* thisPtr, ABI.System.Type key, out byte found);
+    internal unsafe delegate int _insert_IntPtr_IntPtr(void* thisPtr, IntPtr key, IntPtr value, out byte replaced);
+    internal unsafe delegate int _insert_Type_Type(void* thisPtr, ABI.System.Type key, ABI.System.Type value, out byte replaced);
+    internal unsafe delegate int _insert_IntPtr_Type(void* thisPtr, IntPtr key, ABI.System.Type value, out byte replaced);
+    internal unsafe delegate int _insert_Type_IntPtr(void* thisPtr, ABI.System.Type key, IntPtr value, out byte replaced);
+
+    internal unsafe delegate int _invoke_IntPtr_IntPtr(void* thisPtr, IntPtr sender, IntPtr args);
+    internal unsafe delegate int _invoke_IntPtr_Type(void* thisPtr, IntPtr sender, ABI.System.Type args);
+    internal unsafe delegate int _invoke_Type_IntPtr(void* thisPtr, ABI.System.Type sender, IntPtr args);
+    internal unsafe delegate int _invoke_Type_Type(void* thisPtr, ABI.System.Type sender, ABI.System.Type args);
+#endif
+}

src/WinRT.Runtime/Marshalers.cs

@@ -1519,13 +1519,24 @@ static Marshaler()
             }
             else if (type.IsValueType)
             {
-                AbiType = type.FindHelperType();
-                if (AbiType != null)
+                if (type == typeof(bool))
                 {
-                    // Could still be blittable and the 'ABI.*' type exists for other reasons (e.g. it's a mapped type)
-                    if (AbiType.GetMethod("FromAbi", BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Static) == null)
+                    AbiType = typeof(byte);
+                }
+                else if (type == typeof(char))
+                {
+                    AbiType = typeof(ushort);
+                }
+                else
+                {
+                    AbiType = type.FindHelperType();
+                    if (AbiType != null)
                     {
-                        AbiType = null;
+                        // Could still be blittable and the 'ABI.*' type exists for other reasons (e.g. it's a mapped type)
+                        if (AbiType.GetMethod("FromAbi", BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Static) == null)
+                        {
+                            AbiType = null;
+                        }
                     }
                 }
 

src/WinRT.Runtime/Projections.cs

@@ -9,6 +9,7 @@
 using System.ComponentModel;
 using System.Diagnostics.CodeAnalysis;
 using System.Linq;
+using System.Linq.Expressions;
 using System.Numerics;
 using System.Reflection;
 using System.Threading;
@@ -541,5 +542,79 @@ internal static bool TryGetMarshalerTypeForProjectedRuntimeClass<T>(IObjectRefer
             type = null;
             return false;
         }
+
+#if NET
+        internal static Type GetAbiDelegateType(params Type[] typeArgs) => Expression.GetDelegateType(typeArgs);
+#else
+        private class DelegateTypeComparer : IEqualityComparer<Type[]>
+        {
+            public bool Equals(Type[] x, Type[] y)
+            {
+                return x.SequenceEqual(y);
+            }
+
+            public int GetHashCode(Type[] obj)
+            {
+                int hashCode = 0;
+                for (int idx = 0; idx < obj.Length; idx++)
+                {
+                    hashCode ^= obj[idx].GetHashCode();
+                }
+                return hashCode;
+            }
+        }
+
+        private static readonly ConcurrentDictionary<Type[], Type> abiDelegateCache = new(new DelegateTypeComparer())
+        {
+            // IEnumerable
+            [new Type[] { typeof(void*), typeof(IntPtr).MakeByRefType(), typeof(int) }] = typeof(Interop._get_Current_IntPtr),
+            [new Type[] { typeof(void*), typeof(ABI.System.Type).MakeByRefType(), typeof(int) }] = typeof(Interop._get_Current_Type),
+            // IList / IReadOnlyList
+            [new Type[] { typeof(void*), typeof(uint), typeof(IntPtr).MakeByRefType(), typeof(int) }] = typeof(Interop._get_At_IntPtr),
+            [new Type[] { typeof(void*), typeof(uint), typeof(ABI.System.Type).MakeByRefType(), typeof(int) }] = typeof(Interop._get_At_Type),
+            [new Type[] { typeof(void*), typeof(IntPtr), typeof(uint).MakeByRefType(), typeof(byte).MakeByRefType(), typeof(int) }] = typeof(Interop._index_Of_IntPtr),
+            [new Type[] { typeof(void*), typeof(ABI.System.Type), typeof(uint).MakeByRefType(), typeof(byte).MakeByRefType(), typeof(int) }] = typeof(Interop._index_Of_Type),
+            [new Type[] { typeof(void*), typeof(uint), typeof(IntPtr), typeof(int) }] = typeof(Interop._set_At_IntPtr),
+            [new Type[] { typeof(void*), typeof(uint), typeof(ABI.System.Type), typeof(int) }] = typeof(Interop._set_At_Type),
+            [new Type[] { typeof(void*), typeof(IntPtr), typeof(int) }] = typeof(Interop._append_IntPtr),
+            [new Type[] { typeof(void*), typeof(ABI.System.Type), typeof(int) }] = typeof(Interop._append_Type),
+            // IDictionary / IReadOnlyDictionary
+            [new Type[] { typeof(void*), typeof(IntPtr), typeof(IntPtr).MakeByRefType(), typeof(int) }] = typeof(Interop._lookup_IntPtr_IntPtr),
+            [new Type[] { typeof(void*), typeof(ABI.System.Type), typeof(ABI.System.Type).MakeByRefType(), typeof(int) }] = typeof(Interop._lookup_Type_Type),
+            [new Type[] { typeof(void*), typeof(IntPtr), typeof(ABI.System.Type).MakeByRefType(), typeof(int) }] = typeof(Interop._lookup_IntPtr_Type),
+            [new Type[] { typeof(void*), typeof(ABI.System.Type), typeof(IntPtr).MakeByRefType(), typeof(int) }] = typeof(Interop._lookup_Type_IntPtr),
+            [new Type[] { typeof(void*), typeof(IntPtr), typeof(byte).MakeByRefType(), typeof(int) }] = typeof(Interop._has_key_IntPtr),
+            [new Type[] { typeof(void*), typeof(ABI.System.Type), typeof(byte).MakeByRefType(), typeof(int) }] = typeof(Interop._has_key_Type),
+            [new Type[] { typeof(void*), typeof(IntPtr), typeof(IntPtr), typeof(byte).MakeByRefType(), typeof(int) }] = typeof(Interop._insert_IntPtr_IntPtr),
+            [new Type[] { typeof(void*), typeof(ABI.System.Type), typeof(ABI.System.Type), typeof(byte).MakeByRefType(), typeof(int) }] = typeof(Interop._insert_Type_Type),
+            [new Type[] { typeof(void*), typeof(IntPtr), typeof(ABI.System.Type), typeof(byte).MakeByRefType(), typeof(int) }] = typeof(Interop._insert_IntPtr_Type),
+            [new Type[] { typeof(void*), typeof(ABI.System.Type), typeof(IntPtr), typeof(byte).MakeByRefType(), typeof(int) }] = typeof(Interop._insert_Type_IntPtr),
+            // EventHandler
+            [new Type[] { typeof(void*), typeof(IntPtr), typeof(IntPtr), typeof(int) }] = typeof(Interop._invoke_IntPtr_IntPtr),
+            [new Type[] { typeof(void*), typeof(IntPtr), typeof(ABI.System.Type), typeof(int) }] = typeof(Interop._invoke_IntPtr_Type),
+            [new Type[] { typeof(void*), typeof(ABI.System.Type), typeof(IntPtr), typeof(int) }] = typeof(Interop._invoke_Type_IntPtr),
+            [new Type[] { typeof(void*), typeof(ABI.System.Type), typeof(ABI.System.Type), typeof(int) }] = typeof(Interop._invoke_Type_Type),
+        };
+
+        public static void RegisterAbiDelegate(Type[] delegateSignature, Type delegateType)
+        {
+            abiDelegateCache.TryAdd(delegateSignature, delegateType);
+        }
+
+        // The .NET Standard projection can be used in both .NET Core and .NET Framework scenarios.
+        // With the latter, using Expression.GetDelegateType to create custom delegates with void* parameters
+        // doesn't seem to be supported.  So we handle that by pregenerating all the ABI delegates that we need
+        // based on the WinMD and also by allowing apps to register their own if there are any
+        // that we couldn't detect (i.e. types passed as object in WinMD).
+        public static Type GetAbiDelegateType(params Type[] typeArgs)
+        {
+            if (abiDelegateCache.TryGetValue(typeArgs, out var delegateType))
+            {
+                return delegateType;
+            }
+
+            return Expression.GetDelegateType(typeArgs);
+        }
+#endif
     }
 }

src/WinRT.Runtime/Projections/EventHandler.cs

@@ -22,7 +22,7 @@ namespace ABI.System
     static class EventHandler<T>
     {
         public static Guid PIID = GuidGenerator.CreateIID(typeof(global::System.EventHandler<T>));
-        private static readonly global::System.Type Abi_Invoke_Type = Expression.GetDelegateType(new global::System.Type[] { typeof(void*), typeof(IntPtr), Marshaler<T>.AbiType, typeof(int) });
+        private static readonly global::System.Type Abi_Invoke_Type = Projections.GetAbiDelegateType(new global::System.Type[] { typeof(void*), typeof(IntPtr), Marshaler<T>.AbiType, typeof(int) });
 
         private static readonly global::WinRT.Interop.IDelegateVftbl AbiToProjectionVftable;
         public static readonly IntPtr AbiToProjectionVftablePtr;