Use code generator for cloning responses

Author: alexeyzimarev

gen/SourceGenerator/Extensions.cs

@@ -0,0 +1,44 @@
+// Copyright (c) .NET Foundation and Contributors
+// 
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// 
+// http://www.apache.org/licenses/LICENSE-2.0
+// 
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+namespace SourceGenerator;
+
+static class Extensions {
+    public static IEnumerable<ClassDeclarationSyntax> FindClasses(this Compilation compilation, Func<ClassDeclarationSyntax, bool> predicate)
+        => compilation.SyntaxTrees
+            .Select(tree => compilation.GetSemanticModel(tree))
+            .SelectMany(model => model.SyntaxTree.GetRoot().DescendantNodes().OfType<ClassDeclarationSyntax>())
+            .Where(predicate);
+
+    public static IEnumerable<ClassDeclarationSyntax> FindAnnotatedClass(this Compilation compilation, string attributeName, bool strict) {
+        return compilation.FindClasses(
+            syntax => syntax.AttributeLists.Any(list => list.Attributes.Any(CheckAttribute))
+        );
+
+        bool CheckAttribute(AttributeSyntax attr) {
+            var name = attr.Name.ToString();
+            return strict ? name == attributeName : name.StartsWith(attributeName);
+        }
+    }
+
+    public static IEnumerable<ITypeSymbol> GetBaseTypesAndThis(this ITypeSymbol type) {
+        var current = type;
+
+        while (current != null) {
+            yield return current;
+
+            current = current.BaseType;
+        }
+    }
+}

gen/SourceGenerator/ImmutableGenerator.cs

@@ -13,12 +13,6 @@
 // limitations under the License.
 //
 
-using System.Text;
-using Microsoft.CodeAnalysis;
-using Microsoft.CodeAnalysis.CSharp;
-using Microsoft.CodeAnalysis.CSharp.Syntax;
-using Microsoft.CodeAnalysis.Text;
-
 namespace SourceGenerator;
 
 [Generator]
@@ -28,10 +22,7 @@ public void Initialize(GeneratorInitializationContext context) { }
     public void Execute(GeneratorExecutionContext context) {
         var compilation = context.Compilation;
 
-        var mutableClasses = compilation.SyntaxTrees
-            .Select(tree => compilation.GetSemanticModel(tree))
-            .SelectMany(model => model.SyntaxTree.GetRoot().DescendantNodes().OfType<ClassDeclarationSyntax>())
-            .Where(syntax => syntax.AttributeLists.Any(list => list.Attributes.Any(attr => attr.Name.ToString() == "GenerateImmutable")));
+        var mutableClasses = compilation.FindAnnotatedClass("GenerateImmutable", strict: true);
 
         foreach (var mutableClass in mutableClasses) {
             var immutableClass = GenerateImmutableClass(mutableClass, compilation);

gen/SourceGenerator/InheritedCloneGenerator.cs

@@ -0,0 +1,105 @@
+// Copyright (c) .NET Foundation and Contributors
+// 
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// 
+// http://www.apache.org/licenses/LICENSE-2.0
+// 
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+namespace SourceGenerator;
+
+[Generator]
+public class InheritedCloneGenerator : ISourceGenerator {
+    const string AttributeName = "GenerateClone";
+
+    public void Initialize(GeneratorInitializationContext context) { }
+
+    public void Execute(GeneratorExecutionContext context) {
+        var compilation = context.Compilation;
+
+        var candidates = compilation.FindAnnotatedClass(AttributeName, false);
+
+        foreach (var candidate in candidates) {
+            var semanticModel      = compilation.GetSemanticModel(candidate.SyntaxTree);
+            var genericClassSymbol = semanticModel.GetDeclaredSymbol(candidate);
+            if (genericClassSymbol == null) continue;
+
+            // Get the method name from the attribute Name argument
+            var attributeData = genericClassSymbol.GetAttributes().FirstOrDefault(a => a.AttributeClass?.Name == $"{AttributeName}Attribute");
+            var methodName    = (string)attributeData.NamedArguments.FirstOrDefault(arg => arg.Key == "Name").Value.Value;
+
+            // Get the generic argument type where properties need to be copied from
+            var attributeSyntax = candidate.AttributeLists
+                .SelectMany(l => l.Attributes)
+                .FirstOrDefault(a => a.Name.ToString().StartsWith(AttributeName));
+            if (attributeSyntax == null) continue; // This should never happen
+
+            var typeArgumentSyntax = ((GenericNameSyntax)attributeSyntax.Name).TypeArgumentList.Arguments[0];
+            var typeSymbol         = (INamedTypeSymbol)semanticModel.GetSymbolInfo(typeArgumentSyntax).Symbol;
+
+            var code = GenerateMethod(candidate, genericClassSymbol, typeSymbol, methodName);
+            context.AddSource($"{genericClassSymbol.Name}.Clone.g.cs", SourceText.From(code, Encoding.UTF8));
+        }
+    }
+
+    static string GenerateMethod(
+        TypeDeclarationSyntax classToExtendSyntax,
+        INamedTypeSymbol      classToExtendSymbol,
+        INamedTypeSymbol      classToClone,
+        string                methodName
+    ) {
+        var namespaceName         = classToExtendSymbol.ContainingNamespace.ToDisplayString();
+        var className             = classToExtendSyntax.Identifier.Text;
+        var genericTypeParameters = string.Join(", ", classToExtendSymbol.TypeParameters.Select(tp => tp.Name));
+        var classDeclaration      = classToExtendSymbol.TypeParameters.Length > 0 ? $"{className}<{genericTypeParameters}>" : className;
+
+        var all    = classToClone.GetBaseTypesAndThis();
+        var props  = all.SelectMany(x => x.GetMembers().OfType<IPropertySymbol>()).ToArray();
+        var usings = classToExtendSyntax.SyntaxTree.GetCompilationUnitRoot().Usings.Select(u => u.ToString());
+
+        var constructorParams     = classToExtendSymbol.Constructors.First().Parameters.ToArray();
+        var constructorArgs       = string.Join(", ", constructorParams.Select(p => $"original.{GetPropertyName(p.Name, props)}"));
+        var constructorParamNames = constructorParams.Select(p => p.Name).ToArray();
+
+        var properties = props
+            // ReSharper disable once PossibleUnintendedLinearSearchInSet
+            .Where(prop => !constructorParamNames.Contains(prop.Name, StringComparer.OrdinalIgnoreCase) && prop.SetMethod != null)
+            .Select(prop => $"            {prop.Name} = original.{prop.Name},")
+            .ToArray();
+
+        const string template = """
+                                {Usings}
+
+                                namespace {Namespace};
+
+                                public partial class {ClassDeclaration} {
+                                    public static {ClassDeclaration} {MethodName}({OriginalClassName} original)
+                                        => new {ClassDeclaration}({ConstructorArgs}) {
+                                {Properties}
+                                        };
+                                }
+                                """;
+
+        var code = template
+            .Replace("{Usings}", string.Join("\n", usings))
+            .Replace("{Namespace}", namespaceName)
+            .Replace("{ClassDeclaration}", classDeclaration)
+            .Replace("{OriginalClassName}", classToClone.Name)
+            .Replace("{MethodName}", methodName)
+            .Replace("{ConstructorArgs}", constructorArgs)
+            .Replace("{Properties}", string.Join("\n", properties).TrimEnd(','));
+
+        return code;
+
+        static string GetPropertyName(string parameterName, IPropertySymbol[] properties) {
+            var property = properties.FirstOrDefault(p => string.Equals(p.Name, parameterName, StringComparison.OrdinalIgnoreCase));
+            return property?.Name ?? parameterName;
+        }
+    }
+}

gen/SourceGenerator/Properties/launchSettings.json

@@ -0,0 +1,9 @@
+{
+  "$schema": "http://json.schemastore.org/launchsettings.json",
+  "profiles": {
+    "Generators": {
+      "commandName": "DebugRoslynComponent",
+      "targetProject": "../../src/RestSharp/RestSharp.csproj"
+    }
+  }
+}

gen/SourceGenerator/SourceGenerator.csproj

@@ -9,10 +9,18 @@
         <IsPackable>false</IsPackable>
     </PropertyGroup>
     <ItemGroup>
-        <PackageReference Include="Microsoft.CodeAnalysis.Analyzers" PrivateAssets="All" />
-        <PackageReference Include="Microsoft.CodeAnalysis.CSharp" PrivateAssets="All" />
+        <PackageReference Include="Microsoft.CodeAnalysis.Analyzers" PrivateAssets="All"/>
+        <PackageReference Include="Microsoft.CodeAnalysis.CSharp" PrivateAssets="All"/>
     </ItemGroup>
     <ItemGroup>
-        <None Include="$(OutputPath)\$(AssemblyName).dll" Pack="true" PackagePath="analyzers/dotnet/cs" Visible="false" />
+        <None Include="$(OutputPath)\$(AssemblyName).dll" Pack="true" PackagePath="analyzers/dotnet/cs" Visible="false"/>
+    </ItemGroup>
+    <ItemGroup>
+
+        <Using Include="System.Text"/>
+        <Using Include="Microsoft.CodeAnalysis"/>
+        <Using Include="Microsoft.CodeAnalysis.CSharp"/>
+        <Using Include="Microsoft.CodeAnalysis.CSharp.Syntax"/>
+        <Using Include="Microsoft.CodeAnalysis.Text"/>
     </ItemGroup>
 </Project>

src/RestSharp/Extensions/GenerateImmutableAttribute.cs

@@ -16,7 +16,12 @@
 namespace RestSharp.Extensions;
 
 [AttributeUsage(AttributeTargets.Class)]
-class GenerateImmutableAttribute : Attribute { }
+class GenerateImmutableAttribute : Attribute;
+
+[AttributeUsage(AttributeTargets.Class)]
+class GenerateCloneAttribute<T> : Attribute where T : class {
+    public string? Name { get; set; }
+};
 
 [AttributeUsage(AttributeTargets.Property)]
-class Exclude : Attribute { }
+class Exclude : Attribute;

src/RestSharp/Extensions/HttpResponseExtensions.cs

@@ -27,13 +27,12 @@ static class HttpResponseExtensions {
             : new HttpRequestException($"Request failed with status code {httpResponse.StatusCode}");
 #endif
 
-    public static string GetResponseString(this HttpResponseMessage response, byte[] bytes, Encoding clientEncoding) {
+    public static async Task<string> GetResponseString(this HttpResponseMessage response, byte[] bytes, Encoding clientEncoding) {
         var encodingString = response.Content.Headers.ContentType?.CharSet;
         var encoding       = encodingString != null ? TryGetEncoding(encodingString) : clientEncoding;
 
         using var reader = new StreamReader(new MemoryStream(bytes), encoding);
-        return reader.ReadToEnd();
-
+        return await reader.ReadToEndAsync();
         Encoding TryGetEncoding(string es) {
             try {
                 return Encoding.GetEncoding(es);
@@ -69,4 +68,4 @@ Encoding TryGetEncoding(string es) {
             return original == null ? null : streamWriter(original);
         }
     }
-}
+}

src/RestSharp/Response/RestResponse.cs

@@ -13,7 +13,6 @@
 //   limitations under the License. 
 
 using System.Diagnostics;
-using System.Net;
 using System.Text;
 using RestSharp.Extensions;
 
@@ -25,34 +24,13 @@ namespace RestSharp;
 /// Container for data sent back from API including deserialized data
 /// </summary>
 /// <typeparam name="T">Type of data to deserialize to</typeparam>
-[DebuggerDisplay("{" + nameof(DebuggerDisplay) + "()}")]
-public class RestResponse<T>(RestRequest request) : RestResponse(request) {
+[GenerateClone<RestResponse>(Name = "FromResponse")]
+[DebuggerDisplay($"{{{nameof(DebuggerDisplay)}()}}")]
+public partial class RestResponse<T>(RestRequest request) : RestResponse(request) {
     /// <summary>
     /// Deserialized entity data
     /// </summary>
     public T? Data { get; set; }
-
-    public static RestResponse<T> FromResponse(RestResponse response)
-        => new(response.Request) {
-            Content             = response.Content,
-            ContentEncoding     = response.ContentEncoding,
-            ContentHeaders      = response.ContentHeaders,
-            ContentLength       = response.ContentLength,
-            ContentType         = response.ContentType,
-            Cookies             = response.Cookies,
-            ErrorException      = response.ErrorException,
-            ErrorMessage        = response.ErrorMessage,
-            Headers             = response.Headers,
-            IsSuccessStatusCode = response.IsSuccessStatusCode,
-            RawBytes            = response.RawBytes,
-            ResponseStatus      = response.ResponseStatus,
-            ResponseUri         = response.ResponseUri,
-            RootElement         = response.RootElement,
-            Server              = response.Server,
-            StatusCode          = response.StatusCode,
-            StatusDescription   = response.StatusDescription,
-            Version             = response.Version
-        };
 }
 
 /// <summary>
@@ -78,7 +56,7 @@ async Task<RestResponse> GetDefaultResponse() {
 #endif
 
             var bytes   = stream == null ? null : await stream.ReadAsBytes(cancellationToken).ConfigureAwait(false);
-            var content = bytes  == null ? null : httpResponse.GetResponseString(bytes, encoding);
+            var content = bytes  == null ? null : await httpResponse.GetResponseString(bytes, encoding);
 
             return new RestResponse(request) {
                 Content             = content,

src/RestSharp/Response/RestResponseBase.cs

@@ -13,7 +13,7 @@
 // limitations under the License.
 
 using System.Diagnostics;
-using System.Net;
+// ReSharper disable PropertyCanBeMadeInitOnly.Global
 
 namespace RestSharp;
 
@@ -65,12 +65,13 @@ protected RestResponseBase(RestRequest request) {
     public HttpStatusCode StatusCode { get; set; }
 
     /// <summary>
-    /// Whether or not the HTTP response status code indicates success
+    /// Whether the HTTP response status code indicates success
     /// </summary>
     public bool IsSuccessStatusCode { get; set; }
 
     /// <summary>
-    /// Whether or not the HTTP response status code indicates success and no other error occurred (deserialization, timeout, ...)
+    /// Whether the HTTP response status code indicates success and no other error occurred
+    /// (deserialization, timeout, ...)
     /// </summary>
     public bool IsSuccessful => IsSuccessStatusCode && ResponseStatus == ResponseStatus.Completed;
 

src/RestSharp/RestClient.Async.cs

@@ -43,7 +43,7 @@ public async Task<RestResponse> ExecuteAsync(RestRequest request, CancellationTo
     /// <inheritdoc />
     [PublicAPI]
     public async Task<Stream?> DownloadStreamAsync(RestRequest request, CancellationToken cancellationToken = default) {
-        // Make sure we only read the headers so we can stream the content body efficiently
+        // Make sure we only read the headers, so we can stream the content body efficiently
         request.CompletionOption = HttpCompletionOption.ResponseHeadersRead;
         var response = await ExecuteRequestAsync(request, cancellationToken).ConfigureAwait(false);