[SUPER DRAFT] New API for invoking JS functions from C#

eng/testing/tests.wasm.targets

@@ -150,6 +150,11 @@
       <_WasmVFSFilesToCopy Include="@(WasmFilesToIncludeInFileSystem)" />
       <_WasmVFSFilesToCopy TargetPath="%(FileName)%(Extension)" Condition="'%(TargetPath)' == ''" />
 
+      <!-- the custom marshaler support requires the .csproj to include a list of custom marshalers and types
+          that will get included in the generated mono-config so that the runtime knows about them. Without this
+          any application or test relying on custom marshalers will break -->
+      <_WasmItemsToPass Include="@(WasmMarshaledType)" OriginalItemName__="WasmMarshaledType" />
+
       <!-- Example of passing items to the project
 
           <_WasmItemsToPass Include="@(BundleFiles)" OriginalItemName__="BundleFiles" ConditionToUse__="'$(Foo)' != 'true'" />

src/libraries/Common/src/Interop/Browser/Interop.Runtime.cs

@@ -59,6 +59,14 @@ internal static partial class Runtime
         [MethodImplAttribute(MethodImplOptions.InternalCall)]
         internal static extern string CancelPromise(int promiseJSHandle, out int exceptionalResult);
 
+        [MethodImplAttribute(MethodImplOptions.InternalCall)]
+        internal static extern int InvokeJSFunction(
+            string internedFunctionName, int argumentCount,
+            IntPtr type1, IntPtr arg1,
+            IntPtr type2, IntPtr arg2,
+            IntPtr type3, IntPtr arg3
+        );
+
         // / <summary>
         // / Execute the provided string in the JavaScript context
         // / </summary>

src/libraries/System.Private.Runtime.InteropServices.JavaScript/src/ILLink/ILLink.Descriptors.LibraryBuild.xml

@@ -0,0 +1,9 @@
+<linker>
+  <assembly fullname="System.Private.Runtime.InteropServices.JavaScript">
+    <!-- We need to preserve these marshalers during the library build, because whether they are used is not known -->
+    <!--  until end users' applications are built. At that point they can be linked out -->
+    <type fullname="System.Runtime.InteropServices.JavaScript.UriMarshaler" />
+    <type fullname="System.Runtime.InteropServices.JavaScript.DateTimeMarshaler" />
+    <type fullname="System.Runtime.InteropServices.JavaScript.DateTimeOffsetMarshaler" />
+  </assembly>
+</linker>

src/libraries/System.Private.Runtime.InteropServices.JavaScript/src/ILLink/ILLink.Descriptors.xml

@@ -0,0 +1,8 @@
+<linker>
+  <assembly fullname="System.Private.Runtime.InteropServices.JavaScript">
+    <!-- HACK: Hard-coded preserve for all custom marshalers until we implement the msbuild task to generate this on-demand -->
+    <type fullname="System.Runtime.InteropServices.JavaScript.UriMarshaler" />
+    <type fullname="System.Runtime.InteropServices.JavaScript.DateTimeMarshaler" />
+    <type fullname="System.Runtime.InteropServices.JavaScript.DateTimeOffsetMarshaler" />
+  </assembly>
+</linker>

src/libraries/System.Private.Runtime.InteropServices.JavaScript/src/System.Private.Runtime.InteropServices.JavaScript.csproj

@@ -7,6 +7,7 @@
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetsBrowser)' == 'true'">
     <Compile Include="$(CommonPath)Interop\Browser\Interop.Runtime.cs" Link="Common\Interop\Browser\Interop.Runtime.cs" />
+    <Compile Include="System\Runtime\InteropServices\JavaScript\Codegen.cs" />
     <Compile Include="System\Runtime\InteropServices\JavaScript\Runtime.cs" />
     <Compile Include="System\Runtime\InteropServices\JavaScript\Runtime.CS.Owned.cs" />
     <Compile Include="System\Runtime\InteropServices\JavaScript\Runtime.JS.Owned.cs" />
@@ -31,6 +32,9 @@
     <Compile Include="System\Runtime\InteropServices\JavaScript\HostObject.cs" />
     <Compile Include="System\Runtime\InteropServices\JavaScript\Function.cs" />
     <Compile Include="System\Runtime\InteropServices\JavaScript\JSObject.References.cs" />
+    <Compile Include="System\Runtime\InteropServices\JavaScript\DateTimeMarshaler.cs" />
+    <Compile Include="System\Runtime\InteropServices\JavaScript\DateTimeOffsetMarshaler.cs" />
+    <Compile Include="System\Runtime\InteropServices\JavaScript\UriMarshaler.cs" />
   </ItemGroup>
   <ItemGroup>
     <Reference Include="System.Runtime" />

src/libraries/System.Private.Runtime.InteropServices.JavaScript/src/System/Runtime/InteropServices/JavaScript/DateTimeMarshaler.cs

@@ -0,0 +1,36 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
+using System.Runtime.CompilerServices;
+
+namespace System.Runtime.InteropServices.JavaScript
+{
+    public static class DateTimeMarshaler
+    {
+        public static string JavaScriptToInterchangeTransform => @"
+    switch (typeof (value)) {
+        case 'number':
+            return value;
+        default:
+            if (value instanceof Date) {
+                return value.valueOf();
+            } else
+                throw new Error('Value must be a number (msecs since unix epoch), or a Date');
+    }
+";
+        public static string InterchangeToJavaScriptTransform => "return new Date(value)";
+
+        public static DateTime FromJavaScript (double msecsSinceEpoch)
+        {
+            return DateTimeOffset.FromUnixTimeMilliseconds((long)msecsSinceEpoch).UtcDateTime;
+        }
+
+        public static double ToJavaScript (in DateTime dt)
+        {
+            return (double)new DateTimeOffset(dt).ToUnixTimeMilliseconds();
+        }
+    }
+}

src/libraries/System.Private.Runtime.InteropServices.JavaScript/src/System/Runtime/InteropServices/JavaScript/DateTimeOffsetMarshaler.cs

@@ -0,0 +1,26 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
+using System.Runtime.CompilerServices;
+
+namespace System.Runtime.InteropServices.JavaScript
+{
+    public static class DateTimeOffsetMarshaler
+    {
+        public static string JavaScriptToInterchangeTransform => DateTimeMarshaler.JavaScriptToInterchangeTransform;
+        public static string InterchangeToJavaScriptTransform => DateTimeMarshaler.InterchangeToJavaScriptTransform;
+
+        public static DateTimeOffset FromJavaScript (double msecsSinceEpoch)
+        {
+            return DateTimeOffset.FromUnixTimeMilliseconds((long)msecsSinceEpoch);
+        }
+
+        public static double ToJavaScript (in DateTimeOffset dto)
+        {
+            return (double)dto.ToUnixTimeMilliseconds();
+        }
+    }
+}

src/libraries/System.Private.Runtime.InteropServices.JavaScript/src/System/Runtime/InteropServices/JavaScript/JSException.cs

@@ -10,6 +10,12 @@ namespace System.Runtime.InteropServices.JavaScript
     /// </summary>
     public class JSException : Exception
     {
+        public string? Stack;
+
         public JSException(string msg) : base(msg) { }
+
+        public JSException(string msg, string? stack) : base(msg) {
+            Stack = stack;
+        }
     }
 }

src/libraries/System.Private.Runtime.InteropServices.JavaScript/src/System/Runtime/InteropServices/JavaScript/JSObject.References.cs

@@ -48,7 +48,7 @@ internal void AddInFlight()
                 InFlightCounter++;
                 if (InFlightCounter == 1)
                 {
-                    Debug.Assert(InFlight == null);
+                    Debug.Assert(InFlight == null, "InFlight == null");
                     InFlight = GCHandle.Alloc(this, GCHandleType.Normal);
                 }
             }
@@ -61,12 +61,12 @@ internal void ReleaseInFlight()
         {
             lock (this)
             {
-                Debug.Assert(InFlightCounter != 0);
+                Debug.Assert(InFlightCounter != 0, "InFlightCounter != 0");
 
                 InFlightCounter--;
                 if (InFlightCounter == 0)
                 {
-                    Debug.Assert(InFlight.HasValue);
+                    Debug.Assert(InFlight.HasValue, "InFlight.HasValue");
                     InFlight.Value.Free();
                     InFlight = null;
                 }

src/libraries/System.Private.Runtime.InteropServices.JavaScript/src/System/Runtime/InteropServices/JavaScript/JSObject.cs

@@ -1,6 +1,11 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System.Diagnostics.CodeAnalysis;
+using Console = System.Diagnostics.Debug;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
 namespace System.Runtime.InteropServices.JavaScript
 {
     public interface IJSObject
@@ -15,6 +20,30 @@ public interface IJSObject
     /// </summary>
     public partial class JSObject : IJSObject, IDisposable
     {
+        [StructLayout(LayoutKind.Sequential)]
+        private struct InvokeRecord {
+            public object?[] Arguments;
+            // FIXME: Make this object? and update Invoke
+            public object Result;
+            public string? ErrorMessage;
+            public string? ErrorStack;
+        }
+
+        [StructLayout(LayoutKind.Sequential)]
+        private struct GetPropertyRecord {
+            public object Value;
+            public string? ErrorMessage;
+            public string? ErrorStack;
+        }
+
+        [StructLayout(LayoutKind.Sequential)]
+        private struct SetPropertyRecord {
+            public object? Value;
+            public string? ErrorMessage;
+            public string? ErrorStack;
+            public int CreateIfNotExists;
+        }
+
         /// <summary>
         ///   Invoke a named method of the object, or throws a JSException on error.
         /// </summary>
@@ -34,15 +63,23 @@ public partial class JSObject : IJSObject, IDisposable
         ///     valuews.
         ///   </para>
         /// </returns>
-        public object Invoke(string method, params object?[] args)
+        // FIXME: This should be object?, but if we correct it lots of stuff breaks
+        public unsafe object Invoke(string method, params object?[] args)
         {
-            AssertNotDisposed();
-
-            object res = Interop.Runtime.InvokeJSWithArgs(JSHandle, method, args, out int exception);
-            if (exception != 0)
-                throw new JSException((string)res);
-            Interop.Runtime.ReleaseInFlight(res);
-            return res;
+            var record = new InvokeRecord {
+                Arguments = args
+            };
+            var pRecord = (IntPtr)Unsafe.AsPointer(ref record);
+            var invokeResult = Runtime.InvokeJSFunctionByName("INTERNAL._JSObject_Invoke", (IntPtr)JSHandle, method, pRecord);
+            if (invokeResult != InvokeJSResult.Success)
+                throw new JSException($"Invoke result was {invokeResult}");
+            else if (record.ErrorMessage != null)
+                throw new JSException(record.ErrorMessage, record.ErrorStack);
+            else {
+                var result = record.Result;
+                Interop.Runtime.ReleaseInFlight(result);
+                return result;
+            }
         }
 
         public struct EventListenerOptions {
@@ -128,15 +165,21 @@ public void RemoveEventListener(string name, int listenerGCHandle, EventListener
         ///     valuews.
         ///   </para>
         /// </returns>
-        public object GetObjectProperty(string name)
+        public unsafe object GetObjectProperty(string name)
         {
-            AssertNotDisposed();
-
-            object propertyValue = Interop.Runtime.GetObjectProperty(JSHandle, name, out int exception);
-            if (exception != 0)
-                throw new JSException((string)propertyValue);
-            Interop.Runtime.ReleaseInFlight(propertyValue);
-            return propertyValue;
+            var record = new GetPropertyRecord {
+            };
+            var pRecord = (IntPtr)Unsafe.AsPointer(ref record);
+            var invokeResult = Runtime.InvokeJSFunctionByName("INTERNAL._JSObject_GetProperty", (IntPtr)JSHandle, name, pRecord);
+            if (invokeResult != InvokeJSResult.Success)
+                throw new JSException($"Invoke result was {invokeResult}");
+            else if (record.ErrorMessage != null)
+                throw new JSException(record.ErrorMessage, record.ErrorStack);
+            else {
+                var result = record.Value;
+                Interop.Runtime.ReleaseInFlight(result);
+                return result;
+            }
         }
 
         /// <summary>
@@ -149,14 +192,20 @@ public object GetObjectProperty(string name)
         /// array that will be surfaced as a typed ArrayBuffer (byte[], sbyte[], short[], ushort[],
         /// float[], double[]) </param>
         /// <param name="createIfNotExists">Defaults to <see langword="true"/> and creates the property on the javascript object if not found, if set to <see langword="false"/> it will not create the property if it does not exist.  If the property exists, the value is updated with the provided value.</param>
-        /// <param name="hasOwnProperty"></param>
-        public void SetObjectProperty(string name, object value, bool createIfNotExists = true, bool hasOwnProperty = false)
+        /// <param name="hasOwnProperty">does nothing</param>
+        // FIXME: hasOwnProperty is unused.
+        public unsafe void SetObjectProperty(string name, object value, bool createIfNotExists = true, bool hasOwnProperty = false)
         {
-            AssertNotDisposed();
-
-            object setPropResult = Interop.Runtime.SetObjectProperty(JSHandle, name, value, createIfNotExists, hasOwnProperty, out int exception);
-            if (exception != 0)
-                throw new JSException($"Error setting {name} on (js-obj js '{JSHandle}')");
+            var record = new SetPropertyRecord {
+                Value = value,
+                CreateIfNotExists = createIfNotExists ? 1 : 0
+            };
+            var pRecord = (IntPtr)Unsafe.AsPointer(ref record);
+            var invokeResult = Runtime.InvokeJSFunctionByName("INTERNAL._JSObject_SetProperty", (IntPtr)JSHandle, name, pRecord);
+            if (invokeResult != InvokeJSResult.Success)
+                throw new JSException($"Invoke result was {invokeResult}");
+            else if (record.ErrorMessage != null)
+                throw new JSException(record.ErrorMessage, record.ErrorStack);
         }
 
         /// <summary>