Wasm marshaler API for user-defined types; migrate Uri and DateTime to new API

eng/testing/tests.wasm.targets

@@ -163,6 +163,11 @@
       <_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/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 +32,10 @@
     <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" />
+    <Compile Include="System\Runtime\InteropServices\JavaScript\Types.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/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;
                 }