add model serialization method signatures (#3355)

This PR is the first set of PRs to support generation of model
serialization methods. It specifically adds the support for generating
the JSON serialization method signatures for a model.

packages/http-client-csharp/eng/CodeAnalysis.ruleset

@@ -145,8 +145,8 @@
         <Rule Id="SA1505"  Action="None" />          <!-- Opening braces should not be followed by blank line -->
         <Rule Id="SA1506"  Action="None" />          <!-- Element documentation headers should not be followed by blank line -->
         <Rule Id="SA1507"  Action="None" />          <!-- Code should not contain multiple blank lines in a row -->
-        <Rule Id="SA1508"  Action="None" />          <!-- Closing braces should not be preceded by blank line -->
-        <Rule Id="SA1509"  Action="None" />          <!-- Opening braces should not be preceded by blank line -->
+        <Rule Id="SA1508"  Action="Warning" />       <!-- Closing braces should not be preceded by blank line -->
+        <Rule Id="SA1509"  Action="Warning" />       <!-- Opening braces should not be preceded by blank line -->
         <Rule Id="SA1510"  Action="None" />          <!-- Chained statement blocks should not be preceded by blank line -->
         <Rule Id="SA1511"  Action="None" />          <!-- While-do footer should not be preceded by blank line -->
         <Rule Id="SA1512"  Action="None" />          <!-- Single-line comments should not be followed by blank line -->

packages/http-client-csharp/generator/Microsoft.Generator.CSharp.ClientModel/src/ClientModelPlugin.cs

@@ -5,6 +5,7 @@
 using System.ComponentModel.Composition;
 using Microsoft.Generator.CSharp.ClientModel.Expressions;
 using Microsoft.Generator.CSharp.Expressions;
+using Microsoft.Generator.CSharp.Input;
 using Microsoft.Generator.CSharp.Writers;
 
 namespace Microsoft.Generator.CSharp.ClientModel
@@ -25,6 +26,16 @@ public class ClientModelPlugin : CodeModelPlugin
 
         public override ExtensibleSnippets ExtensibleSnippets { get; }
 
+        /// <summary>
+        /// Returns the serialization type providers for the given model type provider.
+        /// </summary>
+        /// <param name="provider">The model type provider.</param>
+        public override TypeProvider[] GetSerializationTypeProviders(ModelTypeProvider provider)
+        {
+            // Add JSON serialization type provider
+            return new TypeProvider[] { new MrwSerializationTypeProvider(provider) };
+        }
+
         [ImportingConstructor]
         public ClientModelPlugin(GeneratorContext context)
             : base(context)

packages/http-client-csharp/generator/Microsoft.Generator.CSharp.ClientModel/src/Expressions/SystemExtensibleSnippets.SystemModelSnippets.cs

@@ -1,4 +1,4 @@
-// Copyright (c) Microsoft Corporation. All rights reserved.
+// Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License.
 
 using System;

packages/http-client-csharp/generator/Microsoft.Generator.CSharp.ClientModel/src/Expressions/SystemSnippets.Serializations.JsonFormat.cs

@@ -0,0 +1,12 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+using Microsoft.Generator.CSharp.Expressions;
+
+namespace Microsoft.Generator.CSharp.ClientModel.Expressions
+{
+    internal static partial class SystemSnippets
+    {
+        internal static StringExpression JsonFormatSerialization = Snippets.Literal("J");
+    }
+}

packages/http-client-csharp/generator/Microsoft.Generator.CSharp.ClientModel/src/Models/Types/MrwSerializationTypeProvider.cs

@@ -0,0 +1,170 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+using System;
+using System.ClientModel.Primitives;
+using System.Linq;
+using System.Text.Json;
+using Microsoft.Generator.CSharp.ClientModel.Expressions;
+using Microsoft.Generator.CSharp.Expressions;
+
+namespace Microsoft.Generator.CSharp.ClientModel
+{
+    /// <summary>
+    /// This class provides the set of serialization models, methods, and interfaces for a given model.
+    /// </summary>
+    internal sealed class MrwSerializationTypeProvider : TypeProvider
+    {
+        private readonly Parameter SerializationOptionsParameter =
+            new("options", null, typeof(ModelReaderWriterOptions), null, ValidationType.None, null);
+        private readonly CSharpType _iJsonModelTInterface;
+        private readonly CSharpType? _iJsonModelObjectInterface;
+        private readonly CSharpType _iPersistableModelTInterface;
+        private readonly CSharpType? _iPersistableModelObjectInterface;
+        private ModelTypeProvider _model;
+
+        public MrwSerializationTypeProvider(ModelTypeProvider model) : base(null)
+        {
+            _model = model;
+            Name = model.Name;
+            // Initialize the serialization interfaces
+            _iJsonModelTInterface = new CSharpType(typeof(IJsonModel<>), _model.Type);
+            _iJsonModelObjectInterface = _model.IsStruct ? (CSharpType)typeof(IJsonModel<object>) : null;
+            _iPersistableModelTInterface = new CSharpType(typeof(IPersistableModel<>), _model.Type);
+            _iPersistableModelObjectInterface = _model.IsStruct ? (CSharpType)typeof(IPersistableModel<object>) : null;
+        }
+
+        public override string Name { get; }
+
+        /// <summary>
+        /// Builds the serialization methods for the model. If the serialization supports JSON, it will build the JSON serialization methods.
+        /// </summary>
+        /// <returns>A list of serialization and deserialization methods for the model.</returns>
+        protected override CSharpMethod[] BuildMethods()
+        {
+            // TO-DO: Add deserialization methods https://github.com/microsoft/typespec/issues/3330
+
+            return new CSharpMethod[]
+            {
+                // Add JSON serialization methods
+                BuildJsonModelWriteMethod(),
+                BuildJsonModelCreateMethod(),
+                // Add IModel methods
+                BuildIModelWriteMethod(),
+                BuildIModelCreateMethod(),
+                BuildIModelGetFormatFromOptionsMethod()
+            };
+        }
+
+        /// <summary>
+        /// Builds the types that the model type serialization implements.
+        /// </summary>
+        /// <returns>An array of <see cref="CSharpType"/> types that the model implements.</returns>
+        protected override CSharpType[] BuildImplements()
+        {
+            int interfaceCount = _iJsonModelObjectInterface != null ? 2 : 1;
+            CSharpType[] interfaces = new CSharpType[interfaceCount];
+            interfaces[0] = _iJsonModelTInterface;
+
+            if (_iJsonModelObjectInterface != null)
+            {
+                interfaces[1] = _iJsonModelObjectInterface;
+            }
+
+            return interfaces;
+        }
+
+        /// <summary>
+        /// Builds the JSON serialization write method for the model.
+        /// </summary>
+        internal CSharpMethod BuildJsonModelWriteMethod()
+        {
+            Parameter utf8JsonWriterParameter = new("writer", null, typeof(Utf8JsonWriter), null, ValidationType.None, null);
+            // void IJsonModel<T>.Write(Utf8JsonWriter writer, ModelReaderWriterOptions options)
+            return new CSharpMethod
+            (
+              new MethodSignature(nameof(IJsonModel<object>.Write), null, null, MethodSignatureModifiers.None, null, null, new[] { utf8JsonWriterParameter, SerializationOptionsParameter }, ExplicitInterface: _iJsonModelTInterface),
+              // TO-DO: Add body for json properties' serialization https://github.com/microsoft/typespec/issues/3330
+              Snippets.EmptyStatement
+            );
+        }
+
+        /// <summary>
+        /// Builds the JSON serialization create method for the model.
+        /// </summary>
+        internal CSharpMethod BuildJsonModelCreateMethod()
+        {
+            Parameter utf8JsonReaderParameter = new("reader", null, typeof(Utf8JsonReader), null, ValidationType.None, null, IsRef: true);
+            // T IJsonModel<T>.Create(ref Utf8JsonReader reader, ModelReaderWriterOptions options)
+            var typeOfT = GetModelArgumentType(_iJsonModelTInterface);
+            return new CSharpMethod
+            (
+              new MethodSignature(nameof(IJsonModel<object>.Create), null, null, MethodSignatureModifiers.None, typeOfT, null, new[] { utf8JsonReaderParameter, SerializationOptionsParameter }, ExplicitInterface: _iJsonModelTInterface),
+              // TO-DO: Call the base model ctor for now until the model properties are serialized https://github.com/microsoft/typespec/issues/3330
+              Snippets.Return(new NewInstanceExpression(typeOfT, Array.Empty<ValueExpression>()))
+            );
+        }
+
+        /// <summary>
+        /// Builds the I model write method.
+        /// </summary>
+        internal CSharpMethod BuildIModelWriteMethod()
+        {
+            // BinaryData IPersistableModel<T>.Write(ModelReaderWriterOptions options)
+            var returnType = typeof(BinaryData);
+            return new CSharpMethod
+            (
+                new MethodSignature(nameof(IPersistableModel<object>.Write), null, null, MethodSignatureModifiers.None, returnType, null, new[] { SerializationOptionsParameter }, ExplicitInterface: _iPersistableModelTInterface),
+                // TO-DO: Call the base model ctor for now until the model properties are serialized https://github.com/microsoft/typespec/issues/3330
+                Snippets.Return(new NewInstanceExpression(returnType, new ValueExpression[] { new StringLiteralExpression(_iPersistableModelTInterface.Name, false) }))
+            );
+        }
+
+        /// <summary>
+        /// Builds the I model create method.
+        /// </summary>
+        internal CSharpMethod BuildIModelCreateMethod()
+        {
+            Parameter dataParameter = new("data", null, typeof(BinaryData), null, ValidationType.None, null);
+            // IPersistableModel<T>.Create(BinaryData data, ModelReaderWriterOptions options)
+            var typeOfT = GetModelArgumentType(_iPersistableModelTInterface);
+            return new CSharpMethod
+            (
+              new MethodSignature(nameof(IPersistableModel<object>.Create), null, null, MethodSignatureModifiers.None, typeOfT, null, new[] { dataParameter, SerializationOptionsParameter }, ExplicitInterface: _iPersistableModelTInterface),
+              // TO-DO: Call the base model ctor for now until the model properties are serialized https://github.com/microsoft/typespec/issues/3330
+              Snippets.Return(new NewInstanceExpression(typeOfT, Array.Empty<ValueExpression>()))
+            );
+        }
+
+        /// <summary>
+        /// Builds the I model GetFormatFromOptions method.
+        /// </summary>
+        internal CSharpMethod BuildIModelGetFormatFromOptionsMethod()
+        {
+            ValueExpression jsonWireFormat = SystemSnippets.JsonFormatSerialization;
+            // ModelReaderWriterFormat IPersistableModel<T>.GetFormatFromOptions(ModelReaderWriterOptions options)
+            return new CSharpMethod
+            (
+              new MethodSignature(nameof(IPersistableModel<object>.GetFormatFromOptions), null, null, MethodSignatureModifiers.None, typeof(string), null, new[] { SerializationOptionsParameter }, ExplicitInterface: _iPersistableModelTInterface),
+              jsonWireFormat
+            );
+        }
+
+        /// <summary>
+        /// Attempts to get the model argument type from the model interface.
+        /// </summary>
+        /// <param name="modelInterface">The <see cref="CSharpType"/> that represents the model interface.</param>
+        /// <returns>The first argument type of <paramref name="modelInterface"/>.</returns>
+        /// <exception cref="InvalidOperationException">Thrown if the <paramref name="modelInterface"/> contains no arguments.</exception>
+        private CSharpType GetModelArgumentType(CSharpType modelInterface)
+        {
+            var interfaceArgs = modelInterface.Arguments;
+            if (!interfaceArgs.Any())
+            {
+                throw new InvalidOperationException($"Expected at least 1 argument for {modelInterface}, but found none.");
+            }
+
+            return interfaceArgs[0];
+        }
+    }
+}

packages/http-client-csharp/generator/Microsoft.Generator.CSharp.ClientModel/src/Properties/AssemblyInfo.cs

@@ -0,0 +1,6 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+using System.Runtime.CompilerServices;
+
+[assembly: InternalsVisibleTo("Microsoft.Generator.CSharp.ClientModel.Tests")]

packages/http-client-csharp/generator/Microsoft.Generator.CSharp.ClientModel/test/Microsoft.Generator.CSharp.ClientModel.Tests.csproj

@@ -0,0 +1,26 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net8.0</TargetFramework>
+    <Nullable>enable</Nullable>
+    <IsPackable>false</IsPackable>
+    <IsTestProject>true</IsTestProject>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.NET.Test.Sdk" />
+    <PackageReference Include="Moq" />
+    <PackageReference Include="NUnit" />
+    <PackageReference Include="NUnit3TestAdapter" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\src\Microsoft.Generator.CSharp.ClientModel.csproj" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <None Update="mocks\Configuration.json">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </None>
+  </ItemGroup>
+</Project>